/* ═══════════════════════════════════════
PAGES — homepage, learn, play, about
═══════════════════════════════════════ */
body.page {
padding: 80px 24px 40px;
line-height: 1.7;
}
/* ── Scroll progress indicator ──────────────────────────────────────────
A 2px bar at the top of the viewport that fills as the user scrolls.
Pure CSS (no JS) using the new `animation-timeline: scroll()` where
supported, with a JS-driven fallback hooked from index.html. */
body.page::before {
content: '';
position: fixed;
top: 0; left: 0;
height: 2px;
width: 0;
background: linear-gradient(90deg, var(--accent) 0%, var(--accent-2) 100%);
z-index: 9000;
transform-origin: 0 50%;
transition: width 80ms linear;
pointer-events: none;
}
body.page[data-scroll]::before { width: var(--scroll-progress, 0%); }
.page-wrap {
max-width: 760px;
margin: 0 auto;
}
.page-wrap h1 {
font-size: 1.6rem;
letter-spacing: .12em;
color: var(--accent);
text-transform: uppercase;
margin-bottom: 8px;
}
.keep-lower {
text-transform: lowercase;
}
.page-wrap h2 {
font-size: 1.15rem;
/* No text-transform: uppercase here — it converts the lowercase λ glyph
to Λ which is both visually unwanted and prone to apex-clipping. h2 is
sentence-case, h1 stays uppercase as the dominant heading. */
line-height: 1.4;
letter-spacing: .02em;
color: var(--text);
margin-top: 40px;
margin-bottom: 14px;
font-weight: 500;
}
.page-wrap h3 {
font-size: 0.92rem;
color: var(--accent);
margin-top: 24px;
margin-bottom: 8px;
font-weight: 500;
}
.page-wrap .lede {
color: var(--muted);
font-size: 0.9rem;
margin-bottom: 32px;
}
.page-wrap p { margin-bottom: 14px; font-size: 0.88rem; color: var(--text); }
.page-wrap ul, .page-wrap ol { margin: 12px 0 16px 24px; }
.page-wrap li { margin-bottom: 6px; font-size: 0.88rem; }
.page-wrap code, .page-wrap kbd {
background: var(--surface);
border: 1px solid var(--border);
padding: 2px 6px;
font-family: 'IBM Plex Mono', monospace;
font-size: 0.85em;
color: var(--accent);
}
.page-wrap pre {
background: var(--surface);
border: 1px solid var(--border);
padding: 14px 18px;
overflow-x: auto;
margin: 12px 0;
font-size: 0.85rem;
}
.page-wrap pre code {
background: transparent;
border: none;
padding: 0;
color: var(--text);
}
/* Section divider: instead of a flat 1px line, a subtle horizontal gradient
that fades in from edge to edge — feels more designed than a plain rule. */
.page-wrap hr {
border: none;
height: 1px;
background: linear-gradient(90deg,
transparent 0%,
var(--border) 20%,
var(--border) 80%,
transparent 100%);
margin: 48px 0;
opacity: 0.7;
}
.hero {
text-align: center;
padding: 60px 0 40px;
}
.hero-eyebrow {
/* Project name displayed above the main title — small, monospace,
low-key. Pairs with the same `λ.bar` mark used as the faint
background title in the 3D scrollytelling section below. */
font-family: 'IBM Plex Mono', monospace;
font-size: 0.78rem;
letter-spacing: 0.32em;
color: var(--accent-2);
text-transform: lowercase;
margin-bottom: 12px;
opacity: 0.85;
}
.hero h1 {
/* Larger and more confident — scales fluidly from mobile to desktop. */
font-size: clamp(2rem, 5.5vw, 3.4rem);
letter-spacing: .14em;
margin-bottom: 18px;
font-weight: 300;
line-height: 1.05;
}
.hero .subtitle {
font-size: clamp(0.9rem, 1.5vw, 1.05rem);
color: var(--muted);
margin-bottom: 32px;
letter-spacing: .02em;
}
.hero .cta {
display: inline-flex;
gap: 12px;
margin-top: 12px;
flex-wrap: wrap;
justify-content: center;
}
.hero .cta a {
position: relative;
padding: 14px 26px;
border: 1px solid var(--accent);
color: var(--accent);
text-transform: uppercase;
letter-spacing: .14em;
font-size: 0.78rem;
text-decoration: none;
transition: background .18s ease-out, color .18s ease-out, transform .18s ease-out, box-shadow .18s ease-out;
overflow: hidden;
}
.hero .cta a:hover {
background: var(--accent);
color: var(--bg);
transform: translateY(-2px);
box-shadow: 0 8px 22px rgba(160, 224, 255, 0.18);
}
.hero .cta a.primary { background: var(--accent); color: var(--bg); }
.hero .cta a.primary:hover {
background: transparent;
color: var(--accent);
box-shadow: 0 8px 22px rgba(160, 224, 255, 0.22);
}
.tile-grid {
display: grid;
grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
gap: 16px;
margin: 30px 0;
}
.tile {
background: var(--surface);
border: 1px solid var(--border);
padding: 22px;
text-decoration: none;
color: var(--text);
transition: border-color .22s ease-out, transform .22s ease-out, box-shadow .22s ease-out, background .22s ease-out;
display: block;
}
.tile:hover {
border-color: var(--accent);
transform: translateY(-3px);
text-decoration: none;
box-shadow: 0 14px 32px rgba(0, 0, 0, 0.35), 0 0 0 1px var(--accent);
background: linear-gradient(180deg, var(--surface), #181828);
}
.tile h3 {
color: var(--accent);
font-size: 0.85rem;
letter-spacing: .1em;
text-transform: uppercase;
margin-bottom: 10px;
}
.tile p {
font-size: 0.78rem;
color: var(--muted);
margin: 0;
}
/* ── Learn page ─────────────────────────────────── */
/* Top-of-viewport progress bar that tracks lesson index. */
.lesson-progress-bar {
position: fixed;
top: 0; left: 0; right: 0;
height: 2px;
background: rgba(255, 255, 255, 0.04);
z-index: 4500;
}
.lesson-progress-fill {
height: 100%;
background: var(--accent);
width: 0%;
transition: width 450ms cubic-bezier(0.4, 0, 0.2, 1);
}
/* Sticky lesson-number nav: stays at the top of the viewport while reading
long lessons. top:50px keeps it clear of the 44px topnav burger. */
.lesson-nav-wrap {
position: sticky;
top: 0;
background: rgba(10, 10, 18, 0.92);
backdrop-filter: blur(8px);
-webkit-backdrop-filter: blur(8px);
padding: 12px 24px 0;
margin: 0 -24px 24px;
z-index: 50;
/* Subtle drop-shadow appears once the nav sticks against the viewport
top — gives users a visual cue that the nav is now floating. */
box-shadow: 0 6px 14px -8px rgba(0, 0, 0, 0.5);
}
.lesson-nav {
display: flex;
gap: 4px;
flex-wrap: wrap;
border-bottom: 1px solid var(--border);
padding-bottom: 12px;
}
.lesson-nav button {
background: transparent;
border: 1px solid var(--border);
color: var(--muted);
padding: 6px 12px;
font-family: inherit;
font-size: 0.72rem;
cursor: pointer;
letter-spacing: .06em;
transition: color 150ms, border-color 150ms;
}
.lesson-nav button.active {
color: var(--bg);
background: var(--accent);
border-color: var(--accent);
}
.lesson-nav button:hover:not(.active) {
color: var(--accent);
border-color: var(--accent);
}
/* Lesson body fades during transitions. */
.lesson-content {
min-height: 400px;
transition: opacity 200ms ease-out, transform 200ms ease-out;
}
.lesson-content.lesson-fading {
opacity: 0;
transform: translateY(-6px);
pointer-events: none;
}
/* Inline Tromp diagrams injected next to EXPR
. */
.lesson-diagram-wrap {
display: flex;
justify-content: center;
align-items: center;
padding: 20px 14px;
margin: -8px 0 18px;
background: var(--surface);
border: 1px solid var(--border);
border-top: none;
}
.lesson-diagram {
display: block;
width: auto;
height: 110px;
max-width: 100%;
filter: drop-shadow(0 0 10px rgba(160, 224, 255, 0.10));
}
/* ── Practice block (per-lesson exercises) ─────────── */
.practice-block {
margin-top: 44px;
padding: 26px 24px 22px;
background: var(--surface);
border: 1px solid var(--border);
border-left: 2px solid var(--accent-2);
}
.practice-heading {
font-size: 0.7rem;
letter-spacing: .22em;
text-transform: uppercase;
color: var(--accent-2);
margin: 0 0 16px;
padding-bottom: 12px;
border-bottom: 1px solid var(--border);
font-weight: 500;
}
.exercise {
position: relative;
padding: 18px 0;
border-bottom: 1px solid var(--border);
transition: opacity 220ms ease-out;
}
.exercise:first-of-type { padding-top: 4px; }
.exercise:last-child { border-bottom: none; padding-bottom: 4px; }
.exercise-prompt {
font-size: 0.88rem;
line-height: 1.7;
margin-bottom: 14px;
color: var(--text);
}
.exercise-prompt code {
font-size: 0.9em;
}
/* Free-form expression answer field */
.exercise-input-row {
display: flex;
gap: 8px;
margin-bottom: 8px;
}
.exercise-input-row input {
flex: 1;
background: var(--bg);
border: 1px solid var(--border);
color: var(--text);
padding: 10px 14px;
font-family: 'IBM Plex Mono', monospace;
font-size: 0.86rem;
outline: none;
transition: border-color .15s;
}
.exercise-input-row input:focus { border-color: var(--accent-2); }
.exercise-input-row input:disabled {
opacity: 0.7;
cursor: not-allowed;
border-color: var(--accent-2);
}
.exercise-input-row .btn {
padding: 8px 18px;
font-size: 0.7rem;
}
/* Multiple-choice options */
.exercise-options {
display: flex;
flex-direction: column;
gap: 6px;
margin-bottom: 10px;
}
.exercise-option {
display: flex;
align-items: center;
gap: 12px;
padding: 10px 14px;
background: var(--surface-2);
border: 1px solid var(--border);
cursor: pointer;
transition: border-color .15s, background .15s;
font-size: 0.84rem;
}
.exercise-option:hover { border-color: var(--accent-2); }
.exercise-option input[type="radio"] {
accent-color: var(--accent-2);
flex-shrink: 0;
}
.exercise-option input[type="radio"]:disabled {
cursor: not-allowed;
}
.exercise-option code {
background: transparent;
border: none;
padding: 0;
color: var(--text);
}
.exercise-actions {
display: flex;
gap: 8px;
margin-bottom: 6px;
}
.exercise-actions .btn {
padding: 6px 14px;
font-size: 0.66rem;
}
.exercise-feedback {
font-size: 0.8rem;
min-height: 1.3em;
padding: 6px 0 0;
font-style: italic;
line-height: 1.5;
}
.exercise-feedback.ok { color: var(--accent-2); font-style: normal; font-weight: 500; }
.exercise-feedback.bad { color: var(--danger); font-style: normal; }
.exercise-feedback.hint { color: var(--warn); font-style: normal; }
/* Solved exercise: subtle dimming + checkmark in the top-right corner. */
.exercise.solved::after {
content: '✓';
position: absolute;
top: 16px;
right: 0;
color: var(--accent-2);
font-size: 1.1rem;
font-weight: 500;
animation: solved-pop 360ms cubic-bezier(0.34, 1.56, 0.64, 1);
}
@keyframes solved-pop {
from { opacity: 0; transform: scale(0.4); }
to { opacity: 1; transform: scale(1); }
}
/* ── Cheatsheet page ─────────────────────────────── */
.page-wrap.cheatsheet { max-width: 1200px; }
.page-wrap.cheatsheet .lede { display: flex; align-items: center; flex-wrap: wrap; gap: 8px; }
.cheat-grid {
display: grid;
grid-template-columns: repeat(auto-fit, minmax(340px, 1fr));
gap: 18px;
margin: 28px 0 12px;
}
.cheat-card {
background: var(--surface);
border: 1px solid var(--border);
padding: 20px 22px 18px;
break-inside: avoid;
page-break-inside: avoid;
}
.cheat-card h2 {
font-size: 0.78rem;
letter-spacing: .14em;
text-transform: uppercase;
color: var(--accent);
margin: 0 0 14px;
padding-bottom: 8px;
border-bottom: 1px solid var(--border);
font-weight: 500;
}
.cheat-card h3 {
font-size: 0.66rem;
letter-spacing: .14em;
text-transform: uppercase;
color: var(--muted);
margin: 18px 0 10px;
font-weight: 500;
}
.cheat-table {
width: 100%;
border-collapse: collapse;
font-size: 0.78rem;
}
.cheat-table td {
padding: 5px 6px;
vertical-align: top;
line-height: 1.5;
}
.cheat-table td:first-child {
white-space: nowrap;
color: var(--text);
font-weight: 500;
}
.cheat-table td:not(:first-child) {
color: var(--muted);
}
.cheat-table code {
font-size: 0.95em;
}
.cheat-card kbd {
background: var(--bg);
border: 1px solid var(--border);
padding: 1px 6px;
border-radius: 2px;
font-family: 'IBM Plex Mono', monospace;
font-size: 0.72rem;
color: var(--accent);
}
.cheat-subtle {
font-size: 0.74rem !important;
color: var(--muted);
line-height: 1.6;
margin: 0 0 10px !important;
font-style: italic;
}
.cheat-subtle code { font-style: normal; }
/* Print: drop the dark theme, render two-column on A4, fit on as few
pages as possible without crowding. */
@media print {
@page { size: A4 portrait; margin: 12mm; }
body.page {
background: white;
color: black;
padding: 0;
line-height: 1.35;
font-size: 9pt;
}
.topnav, .nav-drawer, .nav-overlay, footer.page-footer { display: none !important; }
.page-wrap.cheatsheet {
max-width: none;
margin: 0;
padding: 0;
}
.page-wrap.cheatsheet h1 {
font-size: 16pt;
color: #000;
border-bottom: 1.5pt solid #000;
padding-bottom: 4pt;
margin-bottom: 8pt;
}
.page-wrap.cheatsheet .lede {
font-size: 8pt;
color: #444;
margin-bottom: 8pt;
}
.lede .btn { display: none; }
/* Two columns of cards, tightly packed; let the browser break the
grid across pages naturally — but never split a card. */
.cheat-grid { grid-template-columns: 1fr 1fr; gap: 8pt; }
.cheat-card {
background: white;
border: 0.5pt solid #999;
padding: 6pt 8pt;
box-shadow: none;
color: black;
page-break-inside: avoid;
break-inside: avoid;
}
.cheat-card h2 {
color: #000;
font-size: 10pt;
border-bottom: 0.5pt solid #999;
padding-bottom: 2pt;
margin-bottom: 4pt;
}
.cheat-card h3 {
color: #444;
font-size: 9pt;
margin-top: 4pt;
margin-bottom: 2pt;
}
.cheat-card p,
.cheat-card li { font-size: 8.5pt; line-height: 1.35; }
.cheat-table { font-size: 8pt; }
.cheat-table td { color: #000; padding: 2pt 4pt; }
.cheat-table td:not(:first-child) { color: #444; }
.cheat-card code,
.cheat-table code {
color: #000;
background: transparent;
border: none;
padding: 0;
font-size: 8pt;
}
.cheat-card kbd { background: #f5f5f5; border-color: #999; color: #000; }
.cheat-subtle { color: #555; font-size: 7.5pt; }
/* Hide anything that's interactive-only. */
.cheat-card button,
.cheat-card .btn { display: none !important; }
}
.lesson-content .demo {
background: var(--surface-2);
border: 1px solid var(--border);
padding: 14px;
margin: 16px 0;
}
.lesson-content .demo .demo-label {
font-size: 0.68rem;
color: var(--muted);
text-transform: uppercase;
letter-spacing: .12em;
margin-bottom: 8px;
}
.lesson-content .try {
background: var(--surface);
border: 1px solid var(--accent);
padding: 14px 18px;
margin: 16px 0;
}
.lesson-content .try a {
color: var(--accent);
font-weight: 500;
}
/* ── Play page ─────────────────────────────────── */
.play-frame {
display: flex;
flex-direction: column;
gap: 18px;
max-width: 900px;
margin: 0 auto;
}
.play-status {
display: flex;
justify-content: space-between;
align-items: center;
gap: 14px;
padding: 12px 16px;
background: var(--surface);
border: 1px solid var(--border);
font-size: 0.8rem;
flex-wrap: wrap;
}
.play-status .score { color: var(--accent-2); }
.play-status .level { color: var(--accent); }
.play-status .timer { color: var(--warn); }
/* Difficulty rendered as filled / hollow stars instead of "Difficulty: ★…" */
/* 10-star difficulty strip. The bigger glyph (1.15rem) lets star count
read at a glance — the old 0.85rem version was readable but felt
weightless. `.extreme` styles the all-10-filled strip in a vivid
accent so a level the player should brace for stands out. */
.diff-stars { display: inline-flex; gap: 3px; letter-spacing: 0; }
.diff-stars .star { font-size: 1.15rem; line-height: 1; }
.diff-stars .star.filled { color: var(--warn); text-shadow: 0 0 6px rgba(255, 208, 96, 0.45); }
.diff-stars .star.hollow { color: var(--border); }
.diff-stars.extreme .star.filled {
color: #ff6080;
text-shadow: 0 0 8px rgba(255, 96, 128, 0.55);
}
/* Progress through all puzzles. */
.play-progress {
height: 3px;
background: rgba(255, 255, 255, 0.05);
margin: -8px 0 0;
}
.play-progress-fill {
height: 100%;
background: var(--accent);
width: 0%;
transition: width 450ms cubic-bezier(0.4, 0, 0.2, 1);
}
/* Bigger, more "stage"-y diagram zone with a subtle glow gradient. */
.play-diagram {
background: radial-gradient(ellipse at center,
rgba(160, 224, 255, 0.05) 0%, var(--surface) 70%);
border: 1px solid var(--border);
padding: 50px 30px;
display: flex;
align-items: center;
justify-content: center;
min-height: 360px;
position: relative;
overflow: hidden;
}
.play-diagram svg {
display: block;
max-width: 100%;
max-height: 320px;
width: auto;
height: auto;
filter: drop-shadow(0 0 12px rgba(160, 224, 255, 0.10));
transition: opacity 280ms cubic-bezier(0.4, 0, 0.2, 1),
transform 280ms cubic-bezier(0.4, 0, 0.2, 1);
}
.play-diagram.puzzle-out svg {
opacity: 0;
transform: translateX(-32px);
}
.play-diagram.puzzle-in svg {
animation: puzzle-in 350ms cubic-bezier(0.4, 0, 0.2, 1);
}
@keyframes puzzle-in {
from { opacity: 0; transform: translateX(32px); }
to { opacity: 1; transform: translateX(0); }
}
/* Success: gentle green pulse + drop-shadow flash. */
.play-diagram.flash-success svg {
animation: flash-success 700ms cubic-bezier(0.25, 0.1, 0.25, 1);
}
@keyframes flash-success {
0% { filter: drop-shadow(0 0 12px rgba(160, 224, 255, 0.10)); transform: scale(1); }
35% { filter: drop-shadow(0 0 22px rgba(128, 224, 160, 0.55)); transform: scale(1.04); }
100% { filter: drop-shadow(0 0 12px rgba(160, 224, 255, 0.10)); transform: scale(1); }
}
/* Failure: input shakes side to side. */
.play-input-row {
display: flex;
gap: 8px;
}
.play-input-row input { flex: 1; }
.play-input-row.error-shake {
animation: input-shake 380ms cubic-bezier(0.36, 0.07, 0.19, 0.97);
}
@keyframes input-shake {
0%, 100% { transform: translateX(0); }
15%, 65% { transform: translateX(-7px); }
30%, 80% { transform: translateX(7px); }
45% { transform: translateX(-4px); }
}
.play-feedback {
min-height: 24px;
font-size: 0.84rem;
padding: 8px 0;
transition: color 200ms ease-out;
}
.play-feedback.ok { color: var(--accent-2); }
.play-feedback.bad { color: var(--danger); }
.play-feedback.hint { color: var(--warn); }
/* ── Mode bar (top of the play page) ─────────────────
Lives above the puzzle so picking a mode is the
first decision. The active button gets a filled
accent background so the player can't lose track of
which mode they're in. */
.play-mode-bar {
display: flex;
flex-wrap: wrap;
align-items: center;
gap: 8px;
padding: 10px 14px;
margin: 14px 0 18px;
background: var(--surface);
border: 1px solid var(--border);
border-radius: 6px;
}
.play-mode-btn {
background: transparent;
border: 1px solid var(--border);
color: var(--muted);
font-family: inherit;
font-size: 0.78rem;
letter-spacing: .06em;
padding: 7px 14px;
height: 32px;
display: inline-flex;
align-items: center;
gap: 7px;
cursor: pointer;
transition: color .15s, border-color .15s, background .15s;
}
.play-mode-btn:hover { color: var(--accent); border-color: var(--accent); }
.play-mode-btn.active {
background: var(--accent);
color: var(--bg);
border-color: var(--accent);
}
/* Mode buttons that lead with a vector icon (currently just Daily —
matches the visualiser's monochrome stroke icons). The icon picks up
currentColor so it inverts to bg on `.active`. */
.play-mode-btn--icon svg {
width: 14px;
height: 14px;
display: block;
flex-shrink: 0;
}
.play-mode-chip {
margin-left: auto;
font-size: 0.7rem;
letter-spacing: .14em;
text-transform: uppercase;
color: var(--muted);
}
.play-mode-chip b {
color: var(--accent);
font-weight: 500;
}
/* Action row at the bottom of the puzzle frame. */
.play-action-bar {
display: flex;
gap: 8px;
flex-wrap: wrap;
align-items: center;
}
/* Push the abandon button to the right edge on wide screens so it sits
apart from the per-puzzle controls (Hint/Color/Skip/Reveal). The
mobile breakpoint below resets this so all action buttons share the
same wrap row. */
.play-action-bar .play-abandon-spacer { margin-left: auto; }
/* ── Abandon modal ───────────────────────────────────
Two-step: confirm popup, then score popup. Both
use the same card styling. */
.play-modal {
position: fixed;
inset: 0;
z-index: 9500;
display: flex;
align-items: center;
justify-content: center;
padding: 24px;
}
.play-modal[hidden] { display: none; }
.play-modal-backdrop {
position: absolute;
inset: 0;
background: rgba(10, 10, 18, 0.78);
backdrop-filter: blur(4px);
-webkit-backdrop-filter: blur(4px);
}
.play-modal-card {
position: relative;
background: var(--surface);
border: 1px solid var(--border);
border-radius: 6px;
padding: 22px 26px;
max-width: 420px;
width: 100%;
box-shadow: 0 18px 48px rgba(0, 0, 0, 0.45);
}
.play-modal-title {
font-size: 0.74rem;
letter-spacing: .18em;
text-transform: uppercase;
color: var(--accent);
margin-bottom: 12px;
}
.play-modal-body {
font-size: 0.84rem;
color: var(--text);
line-height: 1.55;
margin: 0 0 18px;
}
.play-modal-scores {
display: flex;
gap: 24px;
margin: 4px 0 22px;
font-family: 'IBM Plex Mono', monospace;
}
.play-modal-scores > div {
display: flex;
flex-direction: column;
gap: 4px;
}
.play-modal-scores b {
font-size: 1.4rem;
color: var(--accent-2);
font-weight: 400;
}
.play-modal-label {
font-size: 0.62rem;
letter-spacing: .14em;
text-transform: uppercase;
color: var(--muted);
}
.play-modal-actions {
display: flex;
gap: 8px;
justify-content: flex-end;
}
/* ── Pre-game overlay ─────────────────────────────────
Sits over the diagram while phase==='pregame'. The
diagram below stays in the DOM (so the play-frame
doesn't reflow when we transition to playing) but
gets blurred & dimmed; the overlay card on top
carries the difficulty picker + Start button. */
.play-diagram-zone {
position: relative;
}
.play-diagram-zone.pregame .play-diagram > svg,
.play-diagram-zone.daily-solved .play-diagram > svg {
filter: blur(8px) brightness(0.55);
transition: filter 220ms ease-out;
}
.play-pregame {
position: absolute;
inset: 0;
display: flex;
align-items: center;
justify-content: center;
z-index: 5;
padding: 24px;
}
.play-pregame[hidden] { display: none; }
/* Daily-solved overlay reuses the pre-game card's positioning + card
styling. The headline + stats are bespoke. */
.play-daily-solved {
position: absolute;
inset: 0;
display: flex;
align-items: center;
justify-content: center;
z-index: 5;
padding: 24px;
}
.play-daily-solved[hidden] { display: none; }
.play-daily-solved-headline {
font-family: 'IBM Plex Mono', monospace;
font-size: 1.6rem;
letter-spacing: .12em;
color: var(--accent-2);
margin: 4px 0 16px;
text-align: center;
}
.play-daily-solved-stats {
display: flex;
gap: 28px;
justify-content: center;
margin: 4px 0 20px;
font-family: 'IBM Plex Mono', monospace;
}
.play-daily-solved-stats > div {
display: flex;
flex-direction: column;
gap: 4px;
align-items: center;
}
.play-daily-solved-stats b {
font-size: 1.4rem;
color: var(--accent);
font-weight: 400;
}
.play-pregame-card {
background: rgba(10, 10, 18, 0.78);
border: 1px solid var(--border);
border-radius: 6px;
padding: 22px 28px;
text-align: center;
max-width: 460px;
width: 100%;
backdrop-filter: blur(6px);
-webkit-backdrop-filter: blur(6px);
box-shadow: 0 18px 48px rgba(0, 0, 0, 0.5);
}
.play-pregame-title {
font-size: 0.74rem;
letter-spacing: .18em;
text-transform: uppercase;
color: var(--accent);
margin-bottom: 14px;
}
.play-pregame-diff {
display: flex;
flex-wrap: wrap;
gap: 6px;
justify-content: center;
margin-bottom: 14px;
}
.play-diff-btn {
background: transparent;
border: 1px solid var(--border);
color: var(--muted);
font-family: inherit;
font-size: 0.72rem;
letter-spacing: .08em;
text-transform: uppercase;
padding: 7px 14px;
cursor: pointer;
transition: color .15s, border-color .15s, background .15s;
}
.play-diff-btn:hover { color: var(--accent); border-color: var(--accent); }
.play-diff-btn.active {
background: var(--accent);
border-color: var(--accent);
color: var(--bg);
}
.play-diff-btn--extreme {
color: #ff8aa0;
border-color: rgba(255, 138, 160, 0.4);
}
.play-diff-btn--extreme:hover { color: #ff6080; border-color: #ff6080; }
.play-diff-btn--extreme.active {
background: #ff6080;
border-color: #ff6080;
color: var(--bg);
}
.play-pregame-blurb {
font-size: 0.78rem;
color: var(--muted);
line-height: 1.55;
margin: 0 0 18px;
}
.play-pregame-start {
font-size: 0.86rem;
letter-spacing: .12em;
text-transform: uppercase;
padding: 10px 24px;
}
/* Run-counter row (hint / skip / colour-active chip). */
.play-counters {
display: flex;
gap: 14px;
flex-wrap: wrap;
font-size: 0.72rem;
letter-spacing: .08em;
color: var(--muted);
padding: 4px 0;
font-variant-numeric: tabular-nums;
}
.play-counters[hidden] { display: none; }
.play-counters #playColorState { color: var(--warn); }
/* Reveal-locked state: only Abandon and Skip stay clickable. The
`.play-locked` class on the frame is added on Reveal and cleared
on next puzzle / Abandon. */
.play-frame.play-locked #playInput,
.play-frame.play-locked #playSubmitBtn,
.play-frame.play-locked #playHintBtn,
.play-frame.play-locked #playColorBtn,
.play-frame.play-locked #playRevealBtn {
opacity: 0.4;
pointer-events: none;
}
.play-frame.play-locked #playInput { background: var(--surface-2); }
/* Clear-data section at the bottom of the page. Sits below the play
frame so it's never in the way of an active run. */
.play-clear-data {
display: flex;
align-items: center;
gap: 14px;
flex-wrap: wrap;
margin: 32px 0 8px;
padding-top: 20px;
border-top: 1px solid var(--border);
}
.play-clear-data-note {
font-size: 0.7rem;
color: var(--muted);
letter-spacing: .04em;
}
/* ── Calendar (past dailies) ─────────────────────────
Replaces the diagram visually while in calendar mode.
Each cell is colour-coded by its history entry:
green = on-time solve, yellow = late solve, blue =
today, dim = future / never solved. */
.play-calendar {
position: absolute;
inset: 0;
z-index: 4;
background: var(--surface);
border: 1px solid var(--border);
display: flex;
flex-direction: column;
padding: 14px 18px 16px;
gap: 10px;
}
.play-calendar[hidden] { display: none; }
.play-calendar-head {
display: flex;
align-items: center;
justify-content: center;
gap: 16px;
}
.play-cal-month {
font-family: 'IBM Plex Mono', monospace;
font-size: 0.92rem;
letter-spacing: .14em;
text-transform: uppercase;
color: var(--accent);
min-width: 180px;
text-align: center;
}
.play-cal-nav {
background: transparent;
border: 1px solid var(--border);
color: var(--muted);
width: 28px; height: 28px;
cursor: pointer;
font-size: 1rem;
font-family: inherit;
line-height: 0;
display: inline-flex;
align-items: center;
justify-content: center;
}
.play-cal-nav:hover { color: var(--accent); border-color: var(--accent); }
.play-cal-dow {
display: grid;
grid-template-columns: repeat(7, 1fr);
gap: 4px;
font-size: 0.62rem;
letter-spacing: .14em;
text-transform: uppercase;
color: var(--muted);
text-align: center;
}
.play-cal-grid {
display: grid;
grid-template-columns: repeat(7, 1fr);
gap: 4px;
flex: 1;
}
.play-cal-cell {
background: var(--bg);
border: 1px solid var(--border);
color: var(--text);
font-family: 'IBM Plex Mono', monospace;
font-size: 0.78rem;
cursor: pointer;
display: flex;
align-items: center;
justify-content: center;
min-height: 32px;
transition: background .15s, border-color .15s, color .15s;
}
.play-cal-cell:hover { border-color: var(--accent); }
.play-cal-cell.empty { background: transparent; border-color: transparent; cursor: default; }
.play-cal-cell.future { color: var(--muted); cursor: not-allowed; opacity: 0.4; }
.play-cal-cell.today {
border-color: var(--accent-2);
color: var(--accent-2);
}
.play-cal-cell.ontime {
background: rgba(128, 224, 160, 0.18);
border-color: rgba(128, 224, 160, 0.55);
color: #a0e8b8;
}
.play-cal-cell.late {
background: rgba(255, 208, 96, 0.16);
border-color: rgba(255, 208, 96, 0.5);
color: #ffd060;
}
.play-cal-legend {
display: flex;
flex-wrap: wrap;
gap: 14px;
font-size: 0.68rem;
color: var(--muted);
align-items: center;
justify-content: center;
}
.play-cal-dot {
display: inline-block;
width: 10px; height: 10px;
margin-right: 5px;
vertical-align: middle;
border: 1px solid currentColor;
}
.play-cal-dot.ontime { background: rgba(128, 224, 160, 0.4); color: #a0e8b8; }
.play-cal-dot.late { background: rgba(255, 208, 96, 0.4); color: #ffd060; }
.play-cal-dot.today { background: transparent; color: var(--accent-2); }
/* ── Daily-solved overlay extras ───────────────────────────── */
.play-daily-streak-emoji {
display: block;
font-size: 1.6rem;
margin: 6px 0 -2px;
letter-spacing: .12em;
}
.play-daily-countdown {
margin-top: 14px;
font-size: 0.74rem;
color: var(--muted);
letter-spacing: .08em;
}
.play-daily-countdown b {
color: var(--text);
font-variant-numeric: tabular-nums;
font-weight: 500;
}
/* ── Confetti (10-streak daily) ────────────────────────────── */
.confetti-host {
position: fixed;
inset: 0;
pointer-events: none;
overflow: hidden;
z-index: 9999;
}
.confetti-piece {
position: absolute;
top: -20px;
width: 10px; height: 14px;
opacity: 0.95;
animation: confetti-fall linear forwards;
will-change: transform;
}
@keyframes confetti-fall {
to {
transform: translateY(110vh) rotate(720deg);
opacity: 0.4;
}
}
@media (prefers-reduced-motion: reduce) {
.confetti-host { display: none; }
}
/* ── Difficulty stars get a tooltip via .tt ────────────────── */
.diff-stars.tt { cursor: help; }
/* Animated underline on inline body links — line draws in left → right.
Targets paragraphs and lists (not navigation, not buttons). */
.page-wrap p a:not(.btn),
.page-wrap li a:not(.btn) {
position: relative;
text-decoration: none;
background-image: linear-gradient(var(--accent), var(--accent));
background-size: 0% 1px;
background-repeat: no-repeat;
background-position: 0 100%;
transition: background-size 320ms cubic-bezier(0.4, 0, 0.2, 1), color 200ms;
padding-bottom: 2px;
}
.page-wrap p a:not(.btn):hover,
.page-wrap li a:not(.btn):hover {
background-size: 100% 1px;
}
footer.page-footer {
margin-top: 80px;
padding-top: 32px;
position: relative;
text-align: center;
font-size: 0.72rem;
color: var(--muted);
letter-spacing: .04em;
line-height: 2;
}
/* Tiny λ-bar ornament above the footer text. */
footer.page-footer::before {
content: '';
position: absolute;
top: 0;
left: 50%;
transform: translateX(-50%);
width: 60px;
height: 2px;
background: linear-gradient(90deg, transparent, var(--accent), transparent);
opacity: 0.6;
}
footer.page-footer a { color: var(--muted); }
footer.page-footer a:hover { color: var(--accent); }
/* ═══════════════════════════════════════
HOME PAGE — graphics, scroll-reveal, illustrations
═══════════════════════════════════════ */
/* Hero positioning context for the background λ filigree.
min-height ensures the lambda has room to be displayed centered without
being clipped by overflow: hidden. */
.page-home .hero {
position: relative;
overflow: hidden;
min-height: 560px;
display: flex;
flex-direction: column;
align-items: center;
justify-content: center;
gap: 14px;
padding: 80px 0 60px;
}
.page-home .hero > * { position: relative; z-index: 1; }
/* Hero background decoration deliberately omitted — both the soft
gradient and the more-defined orb attempts read as visual noise
around the title. The hero keeps its faint λ filigree and the Y
diagram, which carry it on their own. */
/* Background λ — fills the hero box with flex-centering so the glyph is
always centered in the actual visible area, regardless of font-specific
glyph offset. font-size uses clamp() so the lambda scales with viewport
width and never overflows the hero on smaller screens. */
.hero-bg-lambda {
position: absolute;
inset: 0;
display: flex;
align-items: center;
justify-content: center;
font-family: 'IBM Plex Mono', monospace;
font-weight: 300;
font-size: clamp(7rem, 26vw, 13rem);
line-height: 1;
/* Bumped from 0.05 → 0.12 so the stacked shadow below is actually
visible; under 0.05 there's no glyph contrast for a shadow to
read against. */
color: color-mix(in srgb, var(--accent) 12%, transparent);
pointer-events: none;
user-select: none;
z-index: 0;
letter-spacing: 0;
animation: bg-lambda-float 16s ease-in-out infinite;
/* --lx / --ly are unit-vector components (-1..1) set by JS from
mouse position relative to the lambda's centre. The text-shadow
stack uses them to push the shadow in the OPPOSITE direction of
the cursor (i.e. away from the light), with each successive
layer pushed further out for a stair-stepped extrusion. The
transition smooths small mouse jitter without dragging behind
deliberate motion. */
--lx: 0;
--ly: 0;
text-shadow:
calc(var(--lx) * -2px) calc(var(--ly) * -2px) 0 rgba(0, 0, 0, 0.18),
calc(var(--lx) * -4px) calc(var(--ly) * -4px) 0 rgba(0, 0, 0, 0.15),
calc(var(--lx) * -7px) calc(var(--ly) * -7px) 0 rgba(0, 0, 0, 0.12),
calc(var(--lx) * -11px) calc(var(--ly) * -11px) 0 rgba(0, 0, 0, 0.09),
calc(var(--lx) * -16px) calc(var(--ly) * -16px) 0 rgba(0, 0, 0, 0.06),
calc(var(--lx) * -24px) calc(var(--ly) * -24px) 18px rgba(0, 0, 0, 0.22);
transition: text-shadow .25s ease-out;
}
@keyframes bg-lambda-float {
0%, 100% { transform: scale(1); }
50% { transform: scale(1.03); }
}
@media (prefers-reduced-motion: reduce) {
.hero-bg-lambda { transition: none; }
}
/* Hero illustration (real Tromp diagram of Y). */
.hero-illustration {
margin: 28px auto 18px;
display: flex;
flex-direction: column;
align-items: center;
gap: 10px;
}
.hero-illustration svg {
display: block;
width: 100%;
max-width: 360px;
max-height: 320px;
height: auto;
filter: drop-shadow(0 0 18px rgba(160, 224, 255, 0.18));
}
.hero-illust-caption {
font-size: 0.66rem;
letter-spacing: .22em;
color: var(--muted);
text-transform: uppercase;
}
/* Hero entrance: title, subtitle, illustration, CTAs rise in sequence. */
.hero > h1,
.hero > .subtitle,
.hero > .hero-illustration,
.hero > .cta {
opacity: 0;
transform: translateY(14px);
animation: hero-rise 700ms cubic-bezier(0.4, 0, 0.2, 1) forwards;
}
.hero > h1 { animation-delay: 80ms; }
.hero > .subtitle { animation-delay: 240ms; }
.hero > .hero-illustration { animation-delay: 380ms; }
.hero > .cta { animation-delay: 880ms; }
@keyframes hero-rise {
from { opacity: 0; transform: translateY(14px); }
to { opacity: 1; transform: translateY(0); }
}
/* Scroll-reveal: section starts faded + offset, slides in when visible. */
.scroll-reveal {
opacity: 0;
transform: translateY(22px);
transition: opacity 700ms cubic-bezier(0.4, 0, 0.2, 1),
transform 700ms cubic-bezier(0.4, 0, 0.2, 1);
will-change: opacity, transform;
}
.scroll-reveal.revealed {
opacity: 1;
transform: translateY(0);
}
/* Tighten the empty space at the top of each Explore tile so the heading
sits closer to the upper edge — the default 22px all-around padding made
the tiles feel airy on top while the body text crowded the bottom. */
.explore-section .tile { padding: 12px 22px 20px; }
.explore-section .tile h3 { margin-bottom: 6px; }
/* Three primitives row inside "What is the λ-calculus?" */
.primitives-row {
display: flex;
justify-content: space-around;
align-items: flex-end;
gap: 24px;
margin: 26px 0 22px;
padding: 24px 18px;
background: var(--surface);
border: 1px solid var(--border);
}
.primitive {
display: flex;
flex-direction: column;
align-items: center;
gap: 10px;
flex: 1;
min-width: 0;
}
.primitive svg {
height: 78px;
width: auto;
max-width: 100%;
filter: drop-shadow(0 0 6px rgba(232, 232, 240, 0.08));
}
.primitive .primitive-label code {
font-size: 0.82rem;
background: transparent;
border: none;
padding: 0;
}
.primitive small {
font-size: 0.64rem;
letter-spacing: .14em;
color: var(--muted);
text-transform: uppercase;
}
/* β-reduction demo inside "Tromp diagrams" */
.reduction-demo {
display: flex;
align-items: center;
justify-content: center;
gap: 30px;
margin: 28px 0 8px;
padding: 28px 18px;
background: var(--surface);
border: 1px solid var(--border);
}
.reduction-step {
display: flex;
flex-direction: column;
align-items: center;
gap: 14px;
flex-shrink: 0;
}
.reduction-step svg {
display: block;
width: auto;
height: 130px;
max-width: 100%;
filter: drop-shadow(0 0 10px rgba(160, 224, 255, 0.12));
}
.reduction-label code {
font-size: 0.78rem;
background: transparent;
border: none;
padding: 0;
}
.reduction-arrow {
font-size: 1.7rem;
color: var(--accent);
font-weight: 300;
align-self: center;
line-height: 1;
/* The arrow gently glides right then back, like a heartbeat for the
reduction's direction. Pure CSS, looped, very subtle. */
animation: reduction-arrow-slide 2.4s cubic-bezier(0.45, 0, 0.55, 1) infinite;
}
@keyframes reduction-arrow-slide {
0%, 100% { transform: translateX(0); opacity: 0.8; }
50% { transform: translateX(8px); opacity: 1; }
}
/* Scroll-driven 3D viewer (scrollytelling pattern).
The outer section is 220vh tall — short enough that the user never feels
blocked, but tall enough that scrolling through it visibly slows the
perceived rate of page advancement (an intentional cue: "look at me,
then keep scrolling"). The inner .scroll-3d-pinned uses sticky to lock
to the viewport for that duration. JS reads the section's bounding
rect to derive 0→1 progress and rotates a single, randomly-chosen
model. */
.scroll-3d-section {
position: relative;
/* No more sticky pinning. The section is just a tall-ish full-bleed
block that scrolls past normally — the JS spin is driven by how
far the section has traveled through the viewport, so the model
rotates while the user scrolls without the page freezing. */
/* Full-bleed: break out of the page-wrap's 760px column so the
model block can use the entire viewport width. */
width: 100vw;
margin-left: calc(50% - 50vw);
margin-right: calc(50% - 50vw);
margin-top: 80px;
margin-bottom: 80px;
}
.scroll-3d-pinned {
/* Was position: sticky; now a normal block. The element keeps its
old class name to avoid churn; "pinned" is just historical. */
position: relative;
height: 80vh;
width: 100%;
overflow: hidden;
/* Soft radial spotlight behind the 3D model. Uses color-mix so the
centre glow follows the active theme accent, and falls off to
var(--bg) at the edges instead of hardcoding the dark hex —
keeps the effect working on light themes too. */
background: radial-gradient(ellipse at center,
color-mix(in srgb, var(--accent) 6%, var(--bg)) 0%,
var(--bg) 70%);
display: flex;
align-items: center;
justify-content: center;
}
/* Big faint header + blurb behind the canvas. Provides context without
competing visually with the rotating model. */
.scroll-3d-bg {
position: absolute;
inset: 0;
display: flex;
flex-direction: column;
align-items: center;
justify-content: center;
text-align: center;
z-index: 1;
pointer-events: none;
padding: 0 32px;
}
.scroll-3d-bg-title {
font-family: 'IBM Plex Mono', monospace;
font-size: clamp(5rem, 18vw, 14rem);
font-weight: 300;
letter-spacing: .12em;
color: var(--accent);
opacity: 0.06;
margin: 0;
line-height: 1;
}
.scroll-3d-bg-blurb {
max-width: 520px;
margin: 24px auto 0;
font-size: 0.92rem;
line-height: 1.6;
color: var(--text);
opacity: 0.18;
}
/* The 3D canvas sits in front of the bg text, behind the meta labels. */
.scroll-3d-stage {
position: absolute;
inset: 0;
z-index: 2;
}
.scroll-3d-stage canvas {
width: 100% !important;
height: 100% !important;
display: block;
background: transparent;
}
/* The current term's name + one-line description, fading on cycle. */
.scroll-3d-meta {
position: absolute;
left: 50%;
bottom: 64px;
transform: translateX(-50%);
text-align: center;
z-index: 3;
pointer-events: none;
transition: opacity 350ms ease-out;
}
.scroll-3d-name {
font-family: 'IBM Plex Mono', monospace;
font-size: 1.4rem;
letter-spacing: .2em;
text-transform: uppercase;
color: var(--accent);
margin-bottom: 6px;
}
.scroll-3d-desc {
font-family: 'IBM Plex Mono', monospace;
font-size: 0.74rem;
letter-spacing: .14em;
text-transform: uppercase;
color: var(--muted);
white-space: nowrap;
}
.scroll-3d-hint {
position: absolute;
bottom: 22px;
left: 50%;
transform: translateX(-50%);
font-size: 0.62rem;
letter-spacing: .26em;
text-transform: uppercase;
color: var(--muted);
opacity: 0.6;
z-index: 3;
animation: scroll-hint-bob 2.4s ease-in-out infinite;
}
@keyframes scroll-hint-bob {
0%, 100% { transform: translateX(-50%) translateY(0); opacity: 0.6; }
50% { transform: translateX(-50%) translateY(4px); opacity: 0.3; }
}
/* When the user has begun scrolling past the section, hide the hint. */
.scroll-3d-section.engaged .scroll-3d-hint { opacity: 0; transition: opacity 300ms; }
/* Reduced-motion: collapse the section so it doesn't waste 4 viewports of
scroll, and skip rendering 3D from JS. */
@media (prefers-reduced-motion: reduce) {
.scroll-3d-section { height: auto; }
.scroll-3d-pinned { position: relative; height: 60vh; }
}
@media (max-width: 600px) {
.scroll-3d-bg-blurb { font-size: 0.82rem; }
.scroll-3d-meta { bottom: 50px; }
.scroll-3d-name { font-size: 1.1rem; }
/* Full-bleed via `100vw + calc(50% - 50vw)` can be a hair wider than
the actual scroll-viewport width when a scrollbar is present, which
gives the page horizontal scroll on phones. Pin the section flush
to the body's edge instead, undoing the body's side padding. */
.scroll-3d-section {
width: auto;
margin-left: -14px;
margin-right: -14px;
}
.scroll-3d-desc { white-space: normal; padding: 0 16px; }
}
/* Combinator gallery — grid of cards, each a real Tromp diagram of a
classic λ-term. Cards link to the visualizer with that expression. */
.combinator-grid {
display: grid;
grid-template-columns: repeat(auto-fit, minmax(140px, 1fr));
gap: 14px;
margin: 28px 0 12px;
}
.combinator-card {
background: var(--surface);
border: 1px solid var(--border);
padding: 22px 14px 18px;
display: flex;
flex-direction: column;
align-items: center;
gap: 12px;
text-align: center;
text-decoration: none;
color: inherit;
transition: border-color 180ms ease-out, transform 180ms ease-out, box-shadow 180ms ease-out;
min-height: 180px;
}
.combinator-card:hover {
border-color: var(--accent);
transform: translateY(-2px);
box-shadow: 0 8px 24px rgba(160, 224, 255, 0.08);
text-decoration: none;
}
.combinator-card .card-svg-wrap {
flex: 1;
width: 100%;
height: 90px;
display: flex;
align-items: center;
justify-content: center;
}
/* Size the SVG by its intrinsic aspect ratio (height fixed, width auto),
then center it horizontally in the flex wrap. Avoids the previous
`width: 100%` which forced the SVG box to 110px regardless of the
diagram's actual width — short narrow shapes (I, K, 0) ended up
visually offset because the diagram inside the over-wide SVG had
most of its painted pixels off-axis once stroke-width was layered in. */
.combinator-card svg {
display: block;
height: 90px;
width: auto;
max-width: 100%;
margin: 0 auto;
filter: drop-shadow(0 0 8px rgba(232, 232, 240, 0.06));
}
.combinator-card .combinator-name {
font-size: 0.92rem;
color: var(--accent);
font-weight: 500;
letter-spacing: .08em;
}
.combinator-card .combinator-label {
font-size: 0.62rem;
letter-spacing: .14em;
color: var(--muted);
text-transform: uppercase;
}
/* Tile hover gets a subtle accent gradient + glow ring. */
.tile {
position: relative;
overflow: hidden;
}
.tile::before {
content: '';
position: absolute;
inset: 0;
background: linear-gradient(135deg, transparent 55%, rgba(160, 224, 255, 0.06) 100%);
opacity: 0;
transition: opacity 280ms ease-out;
pointer-events: none;
}
.tile:hover::before { opacity: 1; }
.tile:hover {
box-shadow: 0 0 0 1px var(--accent), 0 6px 24px rgba(160, 224, 255, 0.08);
}
/* Generic class for inline Tromp illustration SVGs (rendered by the same
layout/render code as the visualizer). No `vector-effect` here: we rely on
CSS scaling the SVG proportionally so stroke-width and stroke-dasharray
stay in sync (the draw-in animation needs that). */
/* ── Mobile: stack the demo blocks ───────────────── */
@media (max-width: 600px) {
.primitives-row {
flex-direction: column;
align-items: center;
gap: 24px;
}
.primitive { flex: 0 0 auto; }
.reduction-demo { flex-direction: column; gap: 18px; }
.reduction-arrow { transform: rotate(90deg); }
.hero-bg-lambda { font-size: 9rem; }
.page-home .hero { min-height: 460px; padding: 50px 0 40px; }
.combinator-grid { grid-template-columns: repeat(auto-fit, minmax(110px, 1fr)); }
}
/* ── Reduced motion: still readable, just no movement ─ */
@media (prefers-reduced-motion: reduce) {
.scroll-reveal,
.hero > h1,
.hero > .subtitle,
.hero > .hero-illustration,
.hero > .cta {
animation: none !important;
transition: none !important;
opacity: 1 !important;
transform: none !important;
}
/* The bg-lambda keeps its faint opacity — only its float animation stops. */
.hero-bg-lambda { animation: none !important; }
}
/* ═══════════════════════════════════════════════════════════════
TREE PAGE — multi-strategy reduction DAG
═══════════════════════════════════════════════════════════════ */
.tree-page .page-wrap.tree-wrap {
max-width: 1400px;
}
.tree-toolbar {
display: flex;
align-items: center;
gap: 10px;
flex-wrap: wrap;
padding: 10px 14px;
margin: 18px 0 10px;
background: var(--panel);
border: 1px solid var(--border);
border-radius: 6px;
}
.tree-expr-input {
flex: 1;
min-width: 200px;
background: var(--bg);
color: var(--fg);
border: 1px solid var(--border);
border-radius: 4px;
padding: 7px 10px;
font-family: 'IBM Plex Mono', monospace;
font-size: 0.78rem;
outline: none;
}
.tree-expr-input:focus {
border-color: var(--accent-2);
}
.tree-toolbar .scr {
display: flex;
align-items: center;
gap: 6px;
}
.tree-toolbar .scr input[type="range"] {
width: 80px;
}
.tree-zoom {
display: flex;
gap: 4px;
}
.tree-stats {
margin-left: auto;
font-size: 0.7rem;
color: var(--muted);
font-family: 'IBM Plex Mono', monospace;
}
.tree-legend {
display: flex;
flex-wrap: wrap;
gap: 14px;
font-size: 0.7rem;
color: var(--muted);
padding: 0 4px 10px;
}
.tree-legend .lg-item { display: flex; align-items: center; gap: 6px; }
.tree-legend .lg-dot {
display: inline-block;
width: 9px; height: 9px;
border-radius: 50%;
}
.tree-legend .lg-sep { opacity: 0.4; }
.tree-canvas-wrap {
position: relative;
width: 100%;
/* Sized so the entire frame fits in the viewport without scrolling.
The deduction (~340px) covers the page padding, h1, lede, toolbar,
legend and footer that sit above and below the canvas. */
height: calc(100vh - 340px);
min-height: 380px;
background:
radial-gradient(circle at 20% 10%, rgba(160, 224, 255, 0.04), transparent 60%),
radial-gradient(circle at 80% 90%, rgba(128, 224, 160, 0.03), transparent 60%),
var(--panel);
border: 1px solid var(--border);
border-radius: 8px;
overflow: hidden;
cursor: grab;
}
.tree-canvas-wrap:active { cursor: grabbing; }
/* CSS-driven fullscreen (matches the visualizer's pane fullscreen):
we don't use the browser's native Fullscreen API because that would
break our document-level keyboard shortcuts and conflict with the
topnav. Instead, .fullscreen pins the wrap to the viewport with
position:fixed and body.has-fullscreen-pane hides everything else
(topnav, drawer, toolbar, legend, footer). Esc and the in-canvas
⛶ button both un-toggle. */
.tree-canvas-wrap.fullscreen {
position: fixed;
inset: 0;
z-index: 9000;
width: 100vw;
height: 100vh;
max-width: none;
min-height: 0;
border-radius: 0;
border: none;
}
body.has-fullscreen-pane { overflow: hidden; }
body.has-fullscreen-pane .topnav,
body.has-fullscreen-pane .nav-drawer,
body.has-fullscreen-pane .nav-overlay,
body.has-fullscreen-pane .tree-toolbar,
body.has-fullscreen-pane .tree-legend,
body.has-fullscreen-pane .page-footer,
body.has-fullscreen-pane .fun-fact,
body.has-fullscreen-pane #funFact,
body.has-fullscreen-pane .tree-wrap > h1,
body.has-fullscreen-pane .tree-wrap > p.lede {
display: none !important;
}
/* Fullscreen toggle: a single button pinned to the top-right corner
of the canvas-wrap that toggles fullscreen in both directions. By
sitting inside the wrap it travels with it when fullscreen kicks
in (the wrap goes position:fixed inset:0). */
.tree-fs-exit {
position: absolute;
top: 14px;
right: 14px;
z-index: 10;
display: inline-flex;
width: 36px;
height: 36px;
align-items: center;
justify-content: center;
background: rgba(20, 26, 32, 0.9);
border: 1px solid var(--border);
border-radius: 4px;
color: var(--text);
font-size: 1.1rem;
cursor: pointer;
font-family: inherit;
}
.tree-fs-exit:hover { color: var(--accent); border-color: var(--accent); }
/* ── Corner zoom controls (tree) ─────────────────────
Mirrors the visualizer's pane zoom widget (.zoom-controls).
Defined here because tree.html doesn't load visualizer.css. */
.zoom-controls {
position: absolute;
bottom: 10px; right: 10px;
display: flex;
gap: 4px;
background: var(--surface);
border: 1px solid var(--border);
padding: 3px;
z-index: 10;
font-size: 0.7rem;
border-radius: 4px;
}
.zoom-btn {
background: transparent;
border: none;
color: var(--muted);
width: 26px; height: 26px;
cursor: pointer;
font-size: 0.95rem;
line-height: 1;
font-family: inherit;
display: inline-flex;
align-items: center;
justify-content: center;
}
.zoom-btn:hover { color: var(--accent); }
.zoom-level {
color: var(--muted);
padding: 0 6px;
align-self: center;
min-width: 42px;
text-align: center;
font-variant-numeric: tabular-nums;
}
/* ── Square glyph button (?) for the tree toolbar ────
Same shape/size treatment as the visualizer's ⚙ / ? buttons so a
single character glyph sits cleanly in a square instead of being
stretched by the default .btn padding/letter-spacing. */
.btn-glyph {
width: 36px;
height: 36px;
padding: 0;
font-size: 1.1rem;
font-weight: 500;
letter-spacing: 0;
text-transform: none;
display: inline-flex;
align-items: center;
justify-content: center;
line-height: 1;
}
/* ── Achievements page ───────────────────────────────
Badge grid where each card is a square-ish tile with an icon on
the left and a title + hint on the right. Locked cards desaturate
the icon and hide it behind a ? glyph; unlocked cards glow with
the accent colour. */
.ach-summary {
margin: 18px 0 24px;
font-size: 0.85rem;
color: var(--muted);
}
.ach-summary .ach-count {
color: var(--accent);
font-variant-numeric: tabular-nums;
font-weight: 500;
}
.ach-progress {
margin-top: 10px;
width: 100%;
height: 4px;
background: var(--surface-2);
border: 1px solid var(--border);
overflow: hidden;
border-radius: 2px;
}
.ach-progress-fill {
height: 100%;
background: linear-gradient(90deg, var(--accent), var(--accent-2));
transition: width .4s var(--ease);
}
.ach-grid {
display: grid;
grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
gap: 14px;
}
.ach-card {
display: flex;
gap: 14px;
padding: 14px 16px;
background: var(--surface);
border: 1px solid var(--border);
border-radius: 6px;
align-items: center;
transition: border-color .18s, transform .18s, box-shadow .18s;
}
.ach-card.unlocked {
border-color: var(--accent);
/* color-mix lets the glow follow the active theme accent instead
of being hard-coded cyan — keeps unlocked cards readable on
light, dracula, monokai, rose, etc. */
box-shadow:
0 0 0 1px color-mix(in srgb, var(--accent) 8%, transparent),
0 4px 20px color-mix(in srgb, var(--accent) 14%, transparent);
}
.ach-card.unlocked:hover { transform: translateY(-2px); }
.ach-card.locked { opacity: 0.55; }
.ach-icon {
flex: 0 0 auto;
width: 56px;
height: 56px;
border-radius: 50%;
display: inline-flex;
align-items: center;
justify-content: center;
font-size: 1.7rem;
font-family: Georgia, 'Times New Roman', serif;
background: var(--surface-2);
border: 1px solid var(--border);
color: var(--muted);
}
.ach-card.unlocked .ach-icon {
background: linear-gradient(135deg,
color-mix(in srgb, var(--accent) 18%, transparent),
color-mix(in srgb, var(--accent-2) 10%, transparent));
border-color: var(--accent);
color: var(--accent);
}
/* ── Gold-tier achievements ─────────────────────────
Reserved for the genuinely hard ones (100k-step reductions, 7-day
streaks, full-combinator marathons, etc.). Theme-agnostic warm
palette — gold reads as "rare" against every theme accent, even
the light one. A slow, subtle shimmer on the unlocked icon
reinforces the rarity without being noisy. Locked gold cards
still hide their info; the gold frame is the only hint that one
of them exists. */
.ach-card.gold {
border-color: #c89740;
background: linear-gradient(180deg,
color-mix(in srgb, #c89740 6%, var(--surface)),
var(--surface));
}
.ach-card.gold .ach-icon {
background: linear-gradient(135deg,
color-mix(in srgb, #ffd866 22%, transparent),
color-mix(in srgb, #c89740 12%, transparent));
border-color: #c89740;
color: #ffd866;
}
.ach-card.gold.unlocked {
border-color: #ffd866;
box-shadow:
0 0 0 1px color-mix(in srgb, #ffd866 10%, transparent),
0 6px 28px color-mix(in srgb, #ffd866 22%, transparent);
}
.ach-card.gold.unlocked .ach-icon {
background: linear-gradient(135deg,
color-mix(in srgb, #ffd866 36%, transparent),
color-mix(in srgb, #c89740 22%, transparent));
border-color: #ffd866;
color: #fff1c0;
animation: gold-shimmer 4.5s ease-in-out infinite;
}
.ach-card.gold.unlocked .ach-title { color: #ffd866; }
@keyframes gold-shimmer {
0%, 100% { box-shadow: 0 0 0 0 color-mix(in srgb, #ffd866 0%, transparent); }
50% { box-shadow: 0 0 24px 2px color-mix(in srgb, #ffd866 40%, transparent); }
}
@media (prefers-reduced-motion: reduce) {
.ach-card.gold.unlocked .ach-icon { animation: none; }
}
.ach-body { min-width: 0; flex: 1 1 auto; }
.ach-title {
font-size: 0.92rem;
font-weight: 500;
letter-spacing: .04em;
color: var(--text);
margin-bottom: 4px;
}
.ach-card.locked .ach-title { color: var(--muted); }
.ach-hint {
font-size: 0.74rem;
color: var(--muted);
line-height: 1.45;
}
/* ── Keyboard shortcuts modal (mirrors visualizer.css so the dialog
actually styles itself on pages that don't load visualizer.css —
tree, halting, etc.) ───────────────────────────────────────── */
.shortcuts-overlay {
position: fixed;
inset: 0;
background: rgba(10, 10, 18, 0.78);
backdrop-filter: blur(6px);
-webkit-backdrop-filter: blur(6px);
display: none;
align-items: center;
justify-content: center;
z-index: 9500;
padding: 24px;
}
.shortcuts-overlay.open {
display: flex;
animation: shortcuts-fade 180ms ease-out;
}
@keyframes shortcuts-fade { from { opacity: 0; } to { opacity: 1; } }
.shortcuts-card {
background: var(--surface);
border: 1px solid var(--border);
max-width: 700px;
width: 100%;
max-height: calc(100vh - 80px);
display: flex;
flex-direction: column;
box-shadow: 0 20px 60px rgba(0, 0, 0, 0.55);
}
.shortcuts-head {
display: flex;
justify-content: space-between;
align-items: center;
padding: 16px 20px;
border-bottom: 1px solid var(--border);
font-size: 0.78rem;
letter-spacing: .14em;
text-transform: uppercase;
color: var(--accent);
}
.shortcuts-close {
background: transparent;
border: 1px solid var(--border);
color: var(--muted);
width: 28px; height: 28px;
cursor: pointer;
font-size: 1rem;
font-family: inherit;
line-height: 1;
}
.shortcuts-close:hover {
color: var(--danger);
border-color: var(--danger);
}
.shortcuts-body {
padding: 18px 22px 20px;
overflow-y: auto;
display: grid;
grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
gap: 14px 26px;
}
.shortcuts-body section h4 {
font-size: 0.66rem;
letter-spacing: .14em;
text-transform: uppercase;
color: var(--muted);
margin: 0 0 10px;
font-weight: 500;
}
.shortcuts-body dl {
display: grid;
grid-template-columns: max-content 1fr;
column-gap: 14px;
row-gap: 7px;
font-size: 0.78rem;
margin: 0;
}
.shortcuts-body dt {
display: flex;
align-items: center;
gap: 4px;
white-space: nowrap;
color: var(--text);
}
.shortcuts-body dd {
margin: 0;
color: var(--muted);
line-height: 1.5;
}
.shortcuts-body kbd {
background: var(--bg);
border: 1px solid var(--border);
padding: 2px 7px;
font-family: 'IBM Plex Mono', monospace;
font-size: 0.74em;
color: var(--fg);
border-radius: 3px;
}
#treeSVG {
display: block;
width: 100%;
height: 100%;
}
/* Nodes */
.tn { cursor: pointer; }
.tn-bg {
fill: rgba(20, 26, 32, 0.9);
stroke: var(--border);
stroke-width: 1;
transition: stroke 120ms, fill 120ms;
}
.tn:hover .tn-bg {
stroke: var(--accent-2);
fill: rgba(28, 36, 44, 0.95);
}
.tn.terminal .tn-bg {
stroke: var(--accent-2);
stroke-dasharray: 3 2;
}
.tn-depth {
fill: var(--muted);
font-family: 'IBM Plex Mono', monospace;
font-size: 8px;
pointer-events: none;
user-select: none;
}
.tn-dot.terminal { stroke: #fff; stroke-width: 1; }
/* Edges */
.te {
pointer-events: visibleStroke;
cursor: help;
transition: stroke-width 120ms, stroke-opacity 120ms;
}
.te:hover {
stroke-opacity: 1 !important;
stroke-width: 4 !important;
}
.tree-edge-tip {
position: absolute;
display: none;
background: rgba(15, 18, 22, 0.96);
color: var(--fg);
border: 1px solid var(--border);
border-radius: 4px;
padding: 4px 8px;
font-family: 'IBM Plex Mono', monospace;
font-size: 0.66rem;
pointer-events: none;
z-index: 10;
white-space: nowrap;
}
.tree-empty {
position: absolute;
inset: 0;
display: flex;
flex-direction: column;
align-items: center;
justify-content: center;
color: var(--muted);
font-size: 0.86rem;
pointer-events: none;
text-align: center;
}
.tree-empty code {
background: var(--bg);
padding: 2px 6px;
border-radius: 3px;
border: 1px solid var(--border);
margin: 0 2px;
}
/* Fullscreen overlay */
.tree-fs {
position: fixed;
inset: 0;
background: rgba(8, 10, 14, 0.92);
backdrop-filter: blur(4px);
z-index: 9000;
display: none;
align-items: center;
justify-content: center;
padding: 30px;
}
.tree-fs.open { display: flex; }
.tree-fs-inner {
background: var(--panel);
border: 1px solid var(--border);
border-radius: 8px;
padding: 18px 22px 22px;
max-width: 95vw;
max-height: 92vh;
display: flex;
flex-direction: column;
gap: 12px;
}
.tree-fs-head {
display: flex;
align-items: center;
gap: 12px;
font-size: 0.86rem;
}
.tree-fs-head > span:first-child {
font-weight: 500;
color: var(--accent-2);
}
.tree-fs-strats {
display: flex;
gap: 6px;
flex-wrap: wrap;
}
.tree-fs-chip {
display: inline-block;
padding: 2px 8px;
background: rgba(255,255,255,0.05);
border: 1px solid var(--c, var(--border));
border-radius: 999px;
color: var(--c, var(--fg));
font-size: 0.65rem;
font-family: 'IBM Plex Mono', monospace;
}
.tree-fs-close {
margin-left: auto;
background: transparent;
border: 1px solid var(--border);
color: var(--fg);
width: 28px; height: 28px;
border-radius: 4px;
cursor: pointer;
font-size: 1.1rem;
line-height: 1;
}
.tree-fs-close:hover { background: var(--bg); border-color: var(--accent-2); }
#treeFsSVG {
display: block;
max-width: 100%;
max-height: 60vh;
background: var(--bg);
border: 1px solid var(--border);
border-radius: 4px;
}
.tree-fs-code {
font-family: 'IBM Plex Mono', monospace;
font-size: 0.78rem;
background: var(--bg);
border: 1px solid var(--border);
padding: 10px 12px;
border-radius: 4px;
white-space: pre-wrap;
word-break: break-word;
max-height: 18vh;
overflow: auto;
color: var(--fg);
}
.tree-fs-actions {
display: flex;
gap: 8px;
justify-content: flex-end;
flex-wrap: wrap;
}
@media (max-width: 700px) {
.tree-canvas-wrap { height: 60vh; min-height: 380px; }
.tree-toolbar { padding: 8px; gap: 6px; }
.tree-stats { width: 100%; margin-left: 0; }
}
/* ── Spawn-in animation ──────────────────────────────────────── */
@keyframes tn-spawn-anim {
0% { transform: scale(0.4); opacity: 0; }
60% { transform: scale(1.05); opacity: 1; }
100% { transform: scale(1); opacity: 1; }
}
.tn-content {
transform-box: fill-box;
transform-origin: center;
}
.tn-content.spawning {
animation: tn-spawn-anim 260ms cubic-bezier(0.34, 1.56, 0.64, 1);
}
/* ── Strategy-path highlight (hover a legend chip) ───────────── */
.lg-strat { cursor: pointer; transition: opacity 120ms; }
.lg-strat:hover { color: var(--fg); }
.tree-canvas-wrap.path-mode .tn,
.tree-canvas-wrap.path-mode .te {
opacity: 0.18;
transition: opacity 120ms;
}
.tree-canvas-wrap.path-mode .tn.path-on,
.tree-canvas-wrap.path-mode .te.path-on {
opacity: 1;
}
.tree-canvas-wrap.path-mode .tn.path-on .tn-bg {
stroke: var(--path-color, var(--accent-2));
stroke-width: 2.4;
fill: rgba(28, 36, 44, 1);
}
.tree-canvas-wrap.path-mode .te.path-on {
stroke: var(--path-color, var(--accent-2)) !important;
stroke-width: 4 !important;
stroke-opacity: 1 !important;
}
.tree-legend kbd {
display: inline-block;
padding: 1px 5px;
border: 1px solid var(--border);
border-radius: 3px;
background: var(--bg);
font-family: 'IBM Plex Mono', monospace;
font-size: 0.62rem;
color: var(--fg);
}
/* ── Minimap ─────────────────────────────────────────────────── */
.tree-minimap {
position: absolute;
right: 12px;
bottom: 12px;
width: 180px;
height: 130px;
border: 1px solid var(--border);
border-radius: 6px;
cursor: pointer;
z-index: 5;
box-shadow: 0 4px 12px rgba(0, 0, 0, 0.4);
}
.tree-minimap .tm-bg {
fill: rgba(15, 18, 22, 0.95);
}
.tree-minimap .tm-node {
fill: rgba(255, 255, 255, 0.85);
}
.tree-minimap .tm-edge {
stroke: rgba(255, 255, 255, 0.35);
stroke-width: 0.8;
fill: none;
}
.tree-minimap .tm-vp {
fill: rgba(160, 224, 255, 0.08);
pointer-events: none;
}
#treeMinimapBtn.active {
border-color: var(--accent-2);
color: var(--accent-2);
}
/* ═══════════════════════════════════════════════════════════════
HISTORY PAGE — vertical timeline scrollytelling
═══════════════════════════════════════════════════════════════ */
.hist-wrap {
max-width: 980px;
}
.hist-wrap > h1 { margin-top: 16px; }
/* Floating year+progress pill (top-right). */
.hist-pill {
position: fixed;
top: 80px;
right: 24px;
z-index: 50;
background: rgba(15, 18, 22, 0.92);
border: 1px solid var(--border);
border-radius: 24px;
padding: 10px 18px 12px;
font-family: 'IBM Plex Mono', monospace;
backdrop-filter: blur(6px);
box-shadow: 0 4px 14px rgba(0, 0, 0, 0.4);
pointer-events: none;
min-width: 130px;
text-align: center;
}
.hist-pill-year {
font-size: 0.86rem;
font-weight: 500;
color: var(--accent-2);
letter-spacing: 0.06em;
white-space: nowrap;
}
.hist-pill-progress {
margin-top: 8px;
height: 2px;
background: rgba(255, 255, 255, 0.08);
border-radius: 1px;
overflow: hidden;
}
.hist-pill-progress-fill {
height: 100%;
background: var(--accent-2);
transition: width 80ms linear;
}
@media (max-width: 700px) {
.hist-pill { top: 64px; right: 12px; padding: 6px 12px 8px; min-width: 100px; }
.hist-pill-year { font-size: 0.7rem; }
}
/* Each historical section. Two-column grid: marker dot + content. */
.hist-section {
display: grid;
grid-template-columns: 64px 1fr;
gap: 24px;
padding: 60px 0;
border-left: 1px dashed transparent;
position: relative;
}
.hist-section::before {
/* The vertical timeline line lives on the page-wrap, but we draw a
subtle local segment within each section so there's continuity even
when sections grow tall. */
content: '';
position: absolute;
left: 31px;
top: 0;
bottom: 0;
width: 1px;
background: linear-gradient(to bottom,
transparent, rgba(160, 224, 255, 0.18) 12%, rgba(160, 224, 255, 0.18) 88%, transparent);
}
.hist-section + .hist-section { padding-top: 32px; }
.hist-marker {
display: flex;
align-items: flex-start;
justify-content: center;
}
.hist-marker > span {
display: inline-block;
position: sticky;
top: 18vh;
background: var(--bg);
border: 1.5px solid var(--accent-2);
color: var(--accent-2);
border-radius: 50%;
width: 60px;
height: 60px;
line-height: 56px;
text-align: center;
font-family: 'IBM Plex Mono', monospace;
font-size: 0.78rem;
font-weight: 500;
letter-spacing: 0.02em;
z-index: 2;
box-shadow: 0 0 0 6px var(--bg);
}
.hist-content {
min-width: 0;
}
.hist-content h2 {
margin: 0 0 16px;
font-family: 'IBM Plex Mono', monospace;
font-weight: 400;
font-size: 1.6rem;
letter-spacing: 0.01em;
color: var(--fg);
text-transform: none;
padding-top: 4px;
line-height: 1.25;
}
.hist-content p {
font-size: 0.94rem;
line-height: 1.72;
color: var(--text);
margin: 0 0 14px;
}
.hist-content p b {
color: var(--accent-2);
font-weight: 500;
}
.hist-content p code,
.hist-content pre code {
font-family: 'IBM Plex Mono', monospace;
font-size: 0.86em;
background: rgba(160, 224, 255, 0.06);
border: 1px solid rgba(160, 224, 255, 0.12);
padding: 1px 6px;
border-radius: 3px;
color: var(--accent);
}
.hist-content pre {
background: var(--panel);
border: 1px solid var(--border);
border-radius: 4px;
padding: 12px 16px;
margin: 16px 0;
overflow-x: auto;
font-size: 0.84rem;
line-height: 1.55;
}
.hist-content pre code {
background: transparent;
border: none;
padding: 0;
color: var(--fg);
}
.hist-aside {
margin: 16px 0 !important;
padding-left: 14px;
border-left: 2px solid var(--border);
font-style: italic;
color: var(--muted) !important;
font-size: 0.86rem !important;
}
.hist-content a {
color: var(--accent);
text-decoration: underline;
text-decoration-color: rgba(160, 224, 255, 0.3);
}
/* Diagram row inside a section. */
.hist-diagram-row {
display: flex;
flex-wrap: wrap;
gap: 16px;
margin: 24px 0 18px;
justify-content: flex-start;
}
.hist-diagram-card {
display: flex;
flex-direction: column;
align-items: center;
background: var(--panel);
border: 1px solid var(--border);
border-radius: 6px;
padding: 14px 16px 12px;
max-width: 100%;
}
.hist-diagram-card svg {
display: block;
max-width: 100%;
height: auto;
}
.hist-diagram-cap {
margin-top: 10px;
font-size: 0.74rem;
text-align: center;
color: var(--muted);
line-height: 1.5;
max-width: 280px;
}
.hist-diagram-cap code {
background: transparent !important;
border: none !important;
padding: 0 !important;
color: var(--accent) !important;
}
.hist-diagram-err {
color: #ff8a8a;
font-family: 'IBM Plex Mono', monospace;
font-size: 0.78rem;
}
@media (max-width: 700px) {
.hist-section { grid-template-columns: 40px 1fr; gap: 14px; padding: 40px 0; }
.hist-section::before { left: 19px; }
.hist-marker > span {
width: 40px; height: 40px; line-height: 36px;
font-size: 0.6rem; top: 10vh;
}
.hist-content h2 { font-size: 1.25rem; }
}
/* ═══════════════════════════════════════════════════════════════
COMBINATOR ZOO
═══════════════════════════════════════════════════════════════ */
.zoo-wrap { max-width: 1200px; }
.zoo-filter {
display: flex;
flex-wrap: wrap;
gap: 6px;
margin: 18px 0 26px;
}
.zoo-cat-btn {
font-size: 0.66rem;
padding: 5px 11px;
text-transform: lowercase;
letter-spacing: 0.04em;
}
.zoo-cat-btn.active {
border-color: var(--accent-2);
color: var(--accent-2);
}
.zoo-grid {
display: grid;
grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
gap: 14px;
}
.zoo-card {
background: var(--panel);
border: 1px solid var(--border);
border-radius: 6px;
padding: 16px 18px 14px;
display: flex;
flex-direction: column;
gap: 10px;
transition: border-color 120ms, transform 120ms;
}
.zoo-card:hover {
border-color: rgba(160, 224, 255, 0.45);
transform: translateY(-1px);
}
.zoo-head {
display: flex;
align-items: baseline;
gap: 12px;
}
.zoo-sym {
font-family: 'IBM Plex Mono', monospace;
font-size: 1.6rem;
font-weight: 400;
color: var(--accent-2);
letter-spacing: 0.02em;
min-width: 1.5em;
}
.zoo-meta { flex: 1; min-width: 0; }
.zoo-bird {
font-family: 'IBM Plex Mono', monospace;
font-size: 0.78rem;
color: var(--fg);
font-style: italic;
}
.zoo-cat-tag {
font-size: 0.6rem;
color: var(--muted);
text-transform: uppercase;
letter-spacing: 0.1em;
margin-top: 2px;
}
.zoo-diag {
display: block;
margin: 6px auto 4px;
max-width: 100%;
height: auto;
}
.zoo-expr {
background: var(--bg);
border: 1px solid var(--border);
border-radius: 3px;
padding: 6px 9px;
margin: 0;
font-size: 0.75rem;
line-height: 1.4;
overflow-x: auto;
color: var(--accent);
font-family: 'IBM Plex Mono', monospace;
}
.zoo-expr code { font-family: inherit; color: inherit; }
.zoo-desc {
font-size: 0.78rem;
line-height: 1.55;
color: var(--text);
margin: 0;
}
.zoo-example {
font-size: 0.72rem;
color: var(--muted);
font-family: 'IBM Plex Mono', monospace;
background: rgba(255, 255, 255, 0.02);
border-left: 2px solid var(--accent-2);
padding: 5px 9px;
margin: 0;
}
.zoo-example code { color: var(--fg); font-family: inherit; }
.zoo-actions {
display: flex;
justify-content: flex-end;
margin-top: auto;
padding-top: 4px;
}
.zoo-actions .btn {
font-size: 0.66rem;
padding: 5px 10px;
}
.zoo-empty {
grid-column: 1 / -1;
text-align: center;
color: var(--muted);
padding: 60px 20px;
font-style: italic;
}
.zoo-note {
font-size: 0.78rem;
color: var(--muted);
margin-top: 32px;
line-height: 1.6;
}
/* ═══════════════════════════════════════════════════════════════
ENCODING LAB
═══════════════════════════════════════════════════════════════ */
.enc-wrap { max-width: 1200px; }
.enc-tabs {
display: flex;
gap: 4px;
margin: 18px 0 0;
border-bottom: 1px solid var(--border);
}
.enc-tab {
background: transparent;
border: 1px solid transparent;
border-bottom: none;
color: var(--muted);
font-family: 'IBM Plex Mono', monospace;
font-size: 0.78rem;
padding: 9px 16px 7px;
cursor: pointer;
border-radius: 6px 6px 0 0;
letter-spacing: 0.04em;
transition: color 120ms, background 120ms;
}
.enc-tab:hover { color: var(--fg); background: rgba(255, 255, 255, 0.02); }
.enc-tab.active {
color: var(--accent-2);
border-color: var(--border);
background: var(--panel);
margin-bottom: -1px;
border-bottom: 1px solid var(--panel);
}
.enc-intro { margin: 22px 0 18px; }
.enc-intro h2 {
font-family: 'IBM Plex Mono', monospace;
font-weight: 400;
font-size: 1.4rem;
margin: 0 0 10px;
text-transform: none;
letter-spacing: 0;
}
.enc-blurb {
color: var(--text);
line-height: 1.7;
font-size: 0.88rem;
margin: 0;
max-width: 880px;
}
.enc-blurb code {
font-size: 0.86em;
background: rgba(160, 224, 255, 0.06);
border: 1px solid rgba(160, 224, 255, 0.12);
padding: 1px 5px;
border-radius: 3px;
color: var(--accent);
}
.enc-encodings {
display: grid;
grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
gap: 12px;
margin: 22px 0 26px;
}
.enc-encoding-card {
background: var(--panel);
border: 1px solid var(--border);
border-radius: 6px;
padding: 14px 16px;
}
.enc-name {
font-family: 'IBM Plex Mono', monospace;
font-size: 0.86rem;
color: var(--accent-2);
margin-bottom: 8px;
letter-spacing: 0.02em;
}
.enc-formula {
background: var(--bg);
border: 1px solid var(--border);
border-radius: 3px;
padding: 7px 10px;
margin: 0 0 8px;
font-size: 0.74rem;
line-height: 1.5;
color: var(--accent);
overflow-x: auto;
}
.enc-tradeoff {
font-size: 0.74rem;
color: var(--muted);
line-height: 1.5;
}
.enc-grid {
display: grid;
grid-template-columns: 90px repeat(calc(var(--cols, 4) - 1), minmax(180px, 1fr));
gap: 1px;
/* Lower-contrast separators — the previous border-coloured gap made the
table read as a bright grid against the dark page. Now the separators
are barely-there, matching the rest of the site's visual rhythm. */
background: rgba(255, 255, 255, 0.04);
border: 1px solid rgba(255, 255, 255, 0.06);
border-radius: 6px;
overflow: hidden;
}
.enc-grid-h,
.enc-grid-vl,
.enc-grid-d {
background: var(--bg);
padding: 10px 12px;
}
.enc-grid-h {
font-family: 'IBM Plex Mono', monospace;
font-size: 0.7rem;
color: var(--muted);
text-transform: uppercase;
letter-spacing: 0.1em;
background: rgba(255, 255, 255, 0.02);
}
.enc-grid-vl {
font-family: 'IBM Plex Mono', monospace;
font-size: 0.78rem;
color: var(--accent-2);
display: flex;
align-items: center;
background: var(--bg);
}
.enc-grid-vl code {
background: transparent;
border: none;
padding: 0;
color: inherit;
}
.enc-grid-d {
position: relative;
display: flex;
align-items: center;
justify-content: center;
min-height: 80px;
}
.enc-grid-d svg {
display: block;
max-width: 100%;
max-height: 220px;
height: auto;
}
.enc-open {
position: absolute;
top: 6px;
right: 8px;
font-size: 0.78rem;
color: var(--muted);
text-decoration: none;
opacity: 0;
transition: opacity 120ms;
}
.enc-grid-d:hover .enc-open { opacity: 1; }
.enc-open:hover { color: var(--accent-2); }
.enc-elide {
font-size: 0.7rem;
color: var(--muted);
font-style: italic;
}
@media (max-width: 800px) {
.enc-grid {
grid-template-columns: 70px repeat(calc(var(--cols, 4) - 1), 1fr);
}
.enc-grid-d { min-height: 60px; padding: 6px; }
.enc-grid-h, .enc-grid-vl { padding: 6px 8px; font-size: 0.66rem; }
}
/* ═══════════════════════════════════════════════════════════════
HALTING PROBLEM — step-by-step reveal
═══════════════════════════════════════════════════════════════ */
.halt-wrap { max-width: 880px; }
.halt-progress {
height: 3px;
background: rgba(255, 255, 255, 0.05);
border-radius: 2px;
margin: 18px 0 28px;
overflow: hidden;
}
.halt-progress-fill {
height: 100%;
background: linear-gradient(90deg, var(--accent) 0%, var(--accent-2) 100%);
width: 0%;
transition: width 320ms cubic-bezier(0.4, 0, 0.2, 1);
}
.halt-steps {
display: flex;
flex-direction: column;
gap: 0;
margin-bottom: 40px;
}
/* Unrevealed steps are removed from layout entirely (display: none).
Revealed steps animate in via the keyframes below — no max-height
tricks, so verdict pills at the bottom can't get clipped. */
.halt-step {
display: none;
grid-template-columns: 56px 1fr;
gap: 20px;
}
.halt-step.revealed {
display: grid;
animation: halt-step-in 360ms cubic-bezier(0.25, 0.9, 0.3, 1);
}
.halt-step.revealed + .halt-step.revealed { margin-top: 32px; }
@keyframes halt-step-in {
from { opacity: 0; transform: translateY(14px); }
to { opacity: 1; transform: translateY(0); }
}
/* The numbered circle. Single rule: a flex container that centers its
text content both axes. The earlier two-rule version had a stale
`align-items: flex-start` from the prototype that pushed the digit
to the top of the circle. */
.halt-step .halt-step-num {
display: flex;
align-items: center;
justify-content: center;
width: 36px;
height: 36px;
border: 1.5px solid var(--accent-2);
border-radius: 50%;
background: var(--bg);
font-family: 'IBM Plex Mono', monospace;
font-size: 0.78rem;
color: var(--accent-2);
}
.halt-step-body {
min-width: 0;
}
.halt-step-body h2 {
margin: 0 0 12px;
font-family: 'IBM Plex Mono', monospace;
font-weight: 400;
font-size: 1.3rem;
color: var(--fg);
text-transform: none;
letter-spacing: 0;
line-height: 1.3;
}
.halt-step-body p {
font-size: 0.92rem;
line-height: 1.7;
color: var(--text);
margin: 0 0 12px;
}
.halt-step-body p code {
font-size: 0.86em;
background: rgba(160, 224, 255, 0.06);
border: 1px solid rgba(160, 224, 255, 0.12);
padding: 1px 5px;
border-radius: 3px;
color: var(--accent);
}
.halt-step-body pre {
background: var(--panel);
border: 1px solid var(--border);
border-left: 2px solid var(--accent);
border-radius: 3px;
padding: 11px 16px;
margin: 14px 0;
font-size: 0.84rem;
line-height: 1.55;
overflow-x: auto;
}
.halt-step-body pre code {
background: transparent;
border: none;
padding: 0;
color: var(--fg);
}
.halt-step-body a {
color: var(--accent);
text-decoration: underline;
text-decoration-color: rgba(160, 224, 255, 0.3);
}
.halt-diag-row {
display: flex;
gap: 14px;
margin: 18px 0 8px;
flex-wrap: wrap;
}
.halt-diag-card {
background: var(--panel);
border: 1px solid var(--border);
border-radius: 6px;
padding: 14px 16px 10px;
display: flex;
flex-direction: column;
align-items: center;
}
.halt-diag-card svg {
display: block;
max-width: 100%;
height: auto;
}
.halt-diag-cap {
margin-top: 8px;
font-size: 0.72rem;
color: var(--muted);
font-family: 'IBM Plex Mono', monospace;
}
.halt-verdict {
display: inline-block;
margin-top: 6px;
padding: 6px 14px;
font-family: 'IBM Plex Mono', monospace;
font-size: 0.82rem;
letter-spacing: 0.04em;
border-radius: 3px;
}
.halt-verdict-bad {
color: #ff8a8a;
background: rgba(255, 138, 138, 0.08);
border: 1px solid rgba(255, 138, 138, 0.3);
}
.halt-verdict-good {
color: var(--accent-2);
background: rgba(128, 224, 160, 0.08);
border: 1px solid rgba(128, 224, 160, 0.3);
}
.halt-controls {
position: sticky;
bottom: 18px;
display: flex;
align-items: center;
gap: 12px;
padding: 12px 16px;
background: rgba(15, 18, 22, 0.94);
border: 1px solid var(--border);
border-radius: 28px;
backdrop-filter: blur(8px);
margin-top: 32px;
box-shadow: 0 6px 20px rgba(0, 0, 0, 0.4);
}
.halt-controls .btn:disabled {
opacity: 0.35;
cursor: not-allowed;
}
.halt-counter {
font-family: 'IBM Plex Mono', monospace;
font-size: 0.78rem;
color: var(--muted);
letter-spacing: 0.06em;
}
@media (max-width: 700px) {
.halt-step { grid-template-columns: 36px 1fr; gap: 12px; }
.halt-step .halt-step-num {
width: 28px; height: 28px; line-height: 24px; font-size: 0.66rem;
}
.halt-step-body h2 { font-size: 1.1rem; }
.halt-controls { flex-wrap: wrap; }
}
/* ═══════════════════════════════════════════════════════════════════════
MOBILE BREAKPOINTS — shared across home, learn, play and content pages.
Sized so the layout works down to ~360px (iPhone SE / small Androids).
═══════════════════════════════════════════════════════════════════════ */
@media (max-width: 700px) {
body.page {
/* The 80px top room was reserved for the fixed burger nav; on a phone
the burger is smaller (48px) so 60px is enough — and the 24px side
padding ate too much horizontal room when paragraphs had to wrap
inside `code` spans. */
padding: 60px 14px 32px;
line-height: 1.65;
}
.page-wrap h1 { font-size: 1.3rem; letter-spacing: .08em; }
.page-wrap h2 { font-size: 1.05rem; margin-top: 28px; }
.page-wrap h3 { font-size: 0.9rem; }
.page-wrap pre {
padding: 12px 14px;
font-size: 0.78rem;
/* Long expressions inside the playground / cheat-sheet would otherwise
force the whole page to scroll sideways. Keep the horizontal scroll
contained to the . */
max-width: 100%;
}
.page-wrap hr { margin: 32px 0; }
/* Home: hero + tiles + CTAs all tighten and the scroll-3D section
gets a shorter pin so the burger doesn't permanently shadow it. */
.hero { padding: 24px 0 24px; }
.hero .cta { gap: 8px; }
.hero .cta a { padding: 11px 18px; font-size: 0.72rem; letter-spacing: .12em; }
.tile-grid { grid-template-columns: 1fr; gap: 12px; margin: 22px 0; }
.tile { padding: 18px; }
/* Learn page: lesson nav becomes scrollable horizontally instead of
wrapping into 4-5 rows that push the lesson body offscreen. */
.lesson-nav-wrap { padding: 10px 14px 0; margin: 0 -14px 20px; }
.lesson-nav {
flex-wrap: nowrap;
overflow-x: auto;
-webkit-overflow-scrolling: touch;
padding-bottom: 10px;
}
.lesson-nav button { flex: 0 0 auto; padding: 6px 10px; font-size: 0.68rem; }
/* ── Play page ─────────────────────────────────────────────────── */
.play-frame { gap: 14px; }
.play-mode-bar {
gap: 6px;
padding: 8px 10px;
margin: 10px 0 14px;
/* All four mode buttons (Normal / Daily / Calendar / Speedrun) plus
the active-mode chip don't fit in one line at 360px; keep them in
a scrollable horizontal track so the player can swipe between
them instead of wrapping into a tall stack that pushes the
diagram below the fold. */
flex-wrap: nowrap;
overflow-x: auto;
-webkit-overflow-scrolling: touch;
}
.play-mode-btn { flex: 0 0 auto; padding: 7px 11px; font-size: 0.74rem; }
.play-mode-chip {
/* On a wrap-nowrap container the chip would scroll off-screen with
the buttons. Push it to its own row underneath. */
margin-left: 0;
flex-basis: 100%;
text-align: left;
padding-top: 4px;
}
.play-status {
padding: 10px 12px;
font-size: 0.74rem;
gap: 8px;
}
.diff-stars .star { font-size: 0.95rem; }
.play-diagram {
padding: 24px 12px;
min-height: 240px;
}
.play-diagram svg { max-height: 220px; }
.play-input-row { flex-direction: column; }
.play-input-row input { width: 100%; }
.play-action-bar { gap: 6px; }
.play-action-bar .btn { font-size: 0.7rem; padding: 9px 12px; }
.play-action-bar .play-abandon-spacer { margin-left: 0; }
.play-pregame, .play-daily-solved { padding: 14px; }
.play-pregame-card { padding: 18px 16px; }
.play-pregame-diff { gap: 5px; }
.play-diff-btn { padding: 7px 10px; font-size: 0.68rem; }
.play-pregame-title { font-size: 0.7rem; }
.play-pregame-blurb { font-size: 0.74rem; }
.play-daily-solved-headline { font-size: 1.25rem; margin: 4px 0 12px; }
.play-daily-solved-stats { gap: 20px; }
.play-counters { gap: 10px; font-size: 0.68rem; }
.play-modal { padding: 14px; }
.play-modal-card { padding: 18px 18px; }
.play-modal-scores { gap: 16px; }
.play-modal-scores b { font-size: 1.15rem; }
.play-clear-data { gap: 10px; margin-top: 22px; }
.play-clear-data .btn { font-size: 0.7rem; padding: 9px 12px; }
/* Calendar: shrink to fit 7 narrow columns at ~50px each. Numbers
stay readable; the dot-row underneath wraps if needed. */
.play-calendar { padding: 10px 10px 12px; }
}
@media (max-width: 420px) {
/* iPhone SE / small Android — the calendar legend would otherwise
wrap into 3 rows and shove the day grid out of view. Hide the
status legend on the smallest screens; the cell colours still
communicate state. */
.play-cal-legend { display: none; }
.play-mode-btn span { font-size: 0.72rem; }
.hero h1 { font-size: clamp(1.6rem, 8vw, 2.2rem); }
}