/* Smart Sudoku Zen, the website. Paper and ink, four seasons, a night mode. */

:root {
  --paper: #f7efe3;
  --paper-raised: #fbf8f2;
  --paper-sunken: #efe4d3;
  --ink: #28241f;
  --ink-soft: #6e645c;
  --line: rgba(40, 36, 33, 0.12);
  --moss: #5b7a4a;
  --vermilion: #c44a34;
  --gold: #b8892f;
  --sky-top: #fdeee9;
  --sky-bottom: #f3d9da;
  --sun: #d6563a;
  --sun-halo: rgba(255, 186, 136, 0.55);
  --ridge-far: rgba(196, 160, 168, 0.35);
  --ridge-mid: rgba(160, 120, 132, 0.28);
  --ridge-near: rgba(128, 92, 104, 0.22);
  --serif: ui-serif, "New York", "Iowan Old Style", "Palatino", Georgia, serif;
  --sans: ui-rounded, -apple-system, BlinkMacSystemFont, "SF Pro Rounded", system-ui, sans-serif;
  --radius: 22px;
  --shadow: 0 18px 50px rgba(70, 45, 20, 0.16);
  color-scheme: light;
}

body[data-season="summer"] { --sky-top: #f3f6e4; --sky-bottom: #dfe9cf; --ridge-far: rgba(140, 170, 140, 0.35); --ridge-mid: rgba(110, 140, 112, 0.28); --ridge-near: rgba(84, 112, 88, 0.22); }
body[data-season="autumn"] { --sky-top: #fceedd; --sky-bottom: #f0d4b4; --ridge-far: rgba(196, 160, 130, 0.35); --ridge-mid: rgba(160, 120, 96, 0.28); --ridge-near: rgba(128, 92, 72, 0.22); }
body[data-season="winter"] { --sky-top: #eef2f6; --sky-bottom: #dbe3ec; --sun: #e9e4da; --sun-halo: rgba(255, 255, 255, 0.6); --ridge-far: rgba(150, 165, 185, 0.35); --ridge-mid: rgba(120, 136, 158, 0.28); --ridge-near: rgba(96, 110, 132, 0.22); }

/* Night: the system setting, or ?theme=dark / ?theme=light to choose. */
:root[data-theme="dark"] {
    --paper: #141a30;
    --paper-raised: #1d2440;
    --paper-sunken: #10152a;
    --ink: #f2ece0;
    --ink-soft: #b4b8c8;
    --line: rgba(242, 236, 224, 0.14);
    --moss: #9cc28a;
    --vermilion: #e2715c;
    --gold: #e0b45c;
    --sky-top: #0f1428;
    --sky-bottom: #222a4a;
    --sun: #f4ecd6;
    --sun-halo: rgba(180, 200, 255, 0.35);
    --ridge-far: rgba(90, 104, 150, 0.35);
    --ridge-mid: rgba(70, 82, 124, 0.35);
    --ridge-near: rgba(52, 62, 98, 0.4);
    --shadow: 0 18px 50px rgba(0, 0, 0, 0.45);
    color-scheme: dark;
  }
:root[data-theme="dark"] body[data-season] { --sky-top: #0f1428; --sky-bottom: #222a4a; --sun: #f4ecd6; }
@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) {
    --paper: #141a30;
    --paper-raised: #1d2440;
    --paper-sunken: #10152a;
    --ink: #f2ece0;
    --ink-soft: #b4b8c8;
    --line: rgba(242, 236, 224, 0.14);
    --moss: #9cc28a;
    --vermilion: #e2715c;
    --gold: #e0b45c;
    --sky-top: #0f1428;
    --sky-bottom: #222a4a;
    --sun: #f4ecd6;
    --sun-halo: rgba(180, 200, 255, 0.35);
    --ridge-far: rgba(90, 104, 150, 0.35);
    --ridge-mid: rgba(70, 82, 124, 0.35);
    --ridge-near: rgba(52, 62, 98, 0.4);
    --shadow: 0 18px 50px rgba(0, 0, 0, 0.45);
    color-scheme: dark;
  }
  :root:not([data-theme="light"]) body[data-season] { --sky-top: #0f1428; --sky-bottom: #222a4a; --sun: #f4ecd6; }
}

* { box-sizing: border-box; }
[hidden] { display: none !important; }
html { scroll-behavior: smooth; }
body {
  margin: 0;
  background: var(--paper);
  color: var(--ink);
  font: 17px/1.55 var(--sans);
  -webkit-font-smoothing: antialiased;
  overflow-x: hidden;
}
img, video { max-width: 100%; height: auto; display: block; }
a { color: inherit; }
h1, h2, h3 { font-family: var(--serif); font-weight: 600; line-height: 1.08; margin: 0; letter-spacing: -0.01em; }
p { margin: 0; }
.visually-hidden { position: absolute; width: 1px; height: 1px; overflow: hidden; clip: rect(0 0 0 0); }
.skip { position: absolute; left: -999px; top: 8px; z-index: 30; background: var(--ink); color: var(--paper); padding: 8px 14px; border-radius: 99px; }
.skip:focus { left: 12px; }
:focus-visible { outline: 3px solid var(--vermilion); outline-offset: 3px; }

/* MARK: - Top bar */

.topbar {
  position: fixed; inset: 0 0 auto 0; z-index: 20;
  display: flex; align-items: center; gap: 16px;
  padding: 14px clamp(16px, 4vw, 40px);
  backdrop-filter: blur(14px) saturate(1.2);
  -webkit-backdrop-filter: blur(14px) saturate(1.2);
  background: color-mix(in srgb, var(--paper) 62%, transparent);
  border-bottom: 1px solid var(--line);
}
.brand { display: flex; align-items: center; gap: 10px; text-decoration: none; font-family: var(--serif); font-size: 19px; }
.brand__name em { font-style: italic; color: var(--vermilion); }
.seasons { display: flex; gap: 4px; margin-inline: auto; background: var(--paper-sunken); padding: 4px; border-radius: 99px; }
.seasons button {
  border: 0; background: none; color: var(--ink-soft); font: 600 14px var(--sans);
  padding: 7px 14px; border-radius: 99px; cursor: pointer; transition: background 0.3s, color 0.3s;
}
.seasons button[aria-pressed="true"] { background: var(--paper-raised); color: var(--ink); box-shadow: 0 2px 8px rgba(0, 0, 0, 0.08); }
.topbar__end { display: flex; gap: 8px; }
.pill {
  border: 1px solid var(--line); background: var(--paper-raised); color: var(--ink);
  font: 600 14px var(--sans); padding: 8px 14px; border-radius: 99px; text-decoration: none; cursor: pointer;
}
.pill--ink { background: var(--ink); color: var(--paper); border-color: transparent; }
.pill--round { width: 38px; padding: 8px 0; font-size: 16px; line-height: 1; }
.seasons__icon { display: none; }
@media (max-width: 900px) {
  .brand__name { display: none; }
}
@media (max-width: 720px) {
  .seasons button { padding: 6px 9px; font-size: 13px; }
  .topbar__end .pill--ink { display: none; }
}
/* Phones: the seasons shrink to symbols, their names stay for screen readers. */
@media (max-width: 560px) {
  .topbar { gap: 8px; }
  .seasons { gap: 2px; }
  .seasons button { padding: 6px 8px; font-size: 16px; line-height: 1; }
  .seasons__icon { display: inline; }
  .seasons__name { position: absolute; width: 1px; height: 1px; overflow: hidden; clip-path: inset(50%); white-space: nowrap; }
  .topbar__end { gap: 6px; }
  .topbar__end .pill:not(.pill--round) { padding-inline: 11px; }
}

/* MARK: - Seal */

.seal {
  display: inline-grid; place-items: center;
  background: var(--vermilion); color: #fbf6ee;
  font: 700 24px/1 "Songti SC", "Hiragino Mincho ProN", var(--serif);
  width: 40px; height: 40px; border-radius: 7px; transform: rotate(-4deg);
  box-shadow: 0 0 0 1px rgba(255, 255, 255, 0.08) inset;
}
.seal--small { width: 30px; height: 30px; font-size: 18px; border-radius: 6px; }
.seal--large { width: 96px; height: 96px; font-size: 60px; border-radius: 14px; margin-bottom: 26px; }
.seal--stamp { width: 34px; height: 34px; font-size: 20px; animation: stamp 900ms 600ms cubic-bezier(0.2, 1.4, 0.4, 1) both; }
@keyframes stamp {
  0% { transform: rotate(-24deg) scale(2.4); opacity: 0; filter: blur(4px); }
  60% { transform: rotate(-4deg) scale(0.92); opacity: 1; filter: blur(0); box-shadow: 0 0 0 18px color-mix(in srgb, var(--vermilion) 18%, transparent); }
  100% { transform: rotate(-4deg) scale(1); box-shadow: 0 0 0 0 transparent; }
}

/* MARK: - Garden story */

.garden-story { height: 360vh; position: relative; }
.stage { position: sticky; top: 0; height: 100vh; height: 100svh; overflow: hidden; }
.sky { position: absolute; inset: 0; background: linear-gradient(var(--sky-top), var(--sky-bottom)); transition: background 1.2s; }
.sun {
  position: absolute; width: min(30vw, 340px); aspect-ratio: 1; right: 14%; top: 14%;
  border-radius: 50%; background: var(--sun);
  box-shadow: 0 0 0 40px color-mix(in srgb, var(--sun-halo) 40%, transparent), 0 0 120px 60px var(--sun-halo);
  transition: background 1.2s, box-shadow 1.2s;
}
.ridges { position: absolute; inset: auto 0 0 0; width: 100%; height: 55%; }
.ridge { transition: fill 1.2s; }
.ridge--far { fill: var(--ridge-far); }
.ridge--mid { fill: var(--ridge-mid); }
.ridge--near { fill: var(--ridge-near); }
.weather { position: absolute; inset: 0; width: 100%; height: 100%; pointer-events: none; z-index: 3; }

.garden { position: absolute; inset: 0; z-index: 2; }
.garden__canvas { width: 100%; height: 100%; display: block; cursor: grab; touch-action: pan-y; }
.garden__canvas:active { cursor: grabbing; }
.garden__still { position: absolute; width: min(56vw, 820px); right: 3vw; bottom: 4vh; }

.hero-copy {
  position: absolute; z-index: 4; left: clamp(20px, 7vw, 120px); top: 19vh; max-width: min(640px, 86vw);
}
.soon {
  display: inline-block; margin: 0 0 18px; padding: 6px 14px; border-radius: 99px; font: 700 14px var(--sans);
  color: var(--vermilion); background: color-mix(in srgb, var(--vermilion) 10%, var(--paper-raised));
  border: 1px solid color-mix(in srgb, var(--vermilion) 32%, transparent);
}
.finale .soon { margin: 0; }
.eyebrow { display: flex; align-items: center; gap: 12px; color: var(--ink-soft); font-weight: 600; letter-spacing: 0.02em; margin-bottom: 20px; }
h1 { font-size: clamp(50px, 7.2vw, 104px); }
.lede { font-size: clamp(18px, 1.6vw, 22px); color: var(--ink-soft); margin-top: 22px; max-width: 30ch; }
.actions { display: flex; flex-wrap: wrap; align-items: center; gap: 12px; margin-top: 32px; }
.actions--center { justify-content: center; margin-top: 0; }
/* Apple's badges unchanged, at least 40 px high, with a quarter of their height as clear space. */
.store-badge { display: block; border-radius: 9px; transition: transform 0.2s; }
.store-badge:hover { transform: translateY(-2px); }
.store-badge img { display: block; height: 48px; width: auto; }
.button {
  display: inline-flex; align-items: center; gap: 10px; border: 0; cursor: pointer;
  font: 600 16px var(--sans); text-decoration: none; padding: 14px 22px; border-radius: 99px;
  transition: transform 0.2s, box-shadow 0.2s, background 0.3s;
}
.button svg { width: 20px; height: 20px; fill: currentColor; }
.button--primary { background: var(--ink); color: var(--paper); box-shadow: var(--shadow); }
.button--primary:hover { transform: translateY(-2px); }
.button--quiet { background: var(--paper-raised); color: var(--ink); border: 1px solid var(--line); }
.button--quiet:hover { background: var(--paper-sunken); }

.counter {
  position: absolute; z-index: 4; right: clamp(20px, 6vw, 90px); bottom: 5vh;
  font: 600 15px var(--sans); color: var(--ink-soft);
  background: color-mix(in srgb, var(--paper-raised) 80%, transparent); padding: 8px 16px; border-radius: 99px;
  border: 1px solid var(--line);
}
.garden-hint {
  position: absolute; z-index: 4; right: clamp(20px, 6vw, 90px); bottom: calc(5vh + 52px); margin: 0;
  font: 600 13px var(--sans); color: var(--ink-soft); opacity: 0.8; pointer-events: none;
}
.garden-tip {
  position: fixed; z-index: 30; width: max-content; max-width: 280px; padding: 12px 16px; border-radius: 16px;
  background: color-mix(in srgb, var(--paper-raised) 92%, transparent); border: 1px solid var(--line); box-shadow: var(--shadow);
  backdrop-filter: blur(10px); -webkit-backdrop-filter: blur(10px);
  font-size: 14px; line-height: 1.45; color: var(--ink-soft); pointer-events: none;
  opacity: 0; transform: translate(-50%, calc(-100% - 6px)) scale(0.96); transition: opacity 0.3s, transform 0.3s;
}
.garden-tip.visible { opacity: 1; transform: translate(-50%, calc(-100% - 14px)); }
.garden-tip strong { display: block; font-family: var(--serif); font-size: 18px; color: var(--ink); margin-bottom: 2px; }
.counter__value { font-family: var(--serif); font-size: 22px; color: var(--ink); font-variant-numeric: tabular-nums; }

.story { list-style: none; margin: 0; padding: 0; position: absolute; z-index: 4; left: clamp(20px, 7vw, 120px); top: 54vh; width: min(420px, calc(100vw - 40px)); }
.story li {
  position: absolute; inset: 0 auto auto 0; opacity: 0; transform: translateY(20px); pointer-events: none;
  transition: opacity 0.6s, transform 0.6s;
  background: color-mix(in srgb, var(--paper-raised) 86%, transparent);
  border: 1px solid var(--line); border-radius: var(--radius); padding: 20px 22px; box-shadow: var(--shadow);
  backdrop-filter: blur(10px); -webkit-backdrop-filter: blur(10px);
}
.story li.visible { opacity: 1; transform: none; pointer-events: auto; }
.story h2 { font-size: 24px; margin-bottom: 8px; }
.story p { color: var(--ink-soft); }
@media (max-width: 820px) {
  .hero-copy { top: 13vh; }
  .store-badge img { height: 40px; }
  .sun { width: 46vw; top: auto; bottom: 30vh; right: 10%; }
  .garden__still { width: 100vw; right: 0; bottom: 8vh; }
  /* Cards stand on the bottom edge and grow upwards, so a long one never runs out of the stage. */
  .story { top: auto; bottom: 14vh; }
  .story li { inset: auto auto 0 0; }
  .counter { bottom: 4vh; }
}
/* Short phones and phones held sideways: the copy gets compact, the garden moves down (garden3d.js) and the
   drag hint gives way. */
@media (max-width: 820px) and (max-height: 760px), (max-height: 500px) {
  .hero-copy { top: max(10vh, 74px); }
  .soon { font-size: 12px; padding: 4px 11px; margin-bottom: 10px; }
  .eyebrow { font-size: 14px; margin-bottom: 10px; }
  h1 { font-size: clamp(34px, 11vw, 50px); }
  .lede { font-size: 16px; line-height: 1.45; margin-top: 12px; }
  .hero-copy .actions { margin-top: 16px; gap: 10px; }
  .hero-copy .button { padding: 10px 16px; font-size: 15px; }
  .garden-hint { display: none; }
  /* Without WebGL the still of the whole garden sits small and centered below the copy. */
  .garden__still { width: auto; height: 30vh; right: 50%; bottom: 3vh; transform: translateX(50%); }
}
/* Phones held sideways: the eyebrow gives way to the update note, so both buttons stay on the stage. */
@media (max-height: 500px) {
  .hero-copy .eyebrow { display: none; }
  h1 { font-size: clamp(30px, 9vh, 40px); }
}
@media (max-height: 500px) and (orientation: landscape) {
  .garden__still { height: 60vh; right: 4vw; bottom: 4vh; transform: none; }
}

/* MARK: - Sections */

.section { padding: clamp(80px, 12vw, 160px) clamp(20px, 6vw, 80px); position: relative; }
.section__head { max-width: 720px; margin: 0 auto 48px; text-align: center; }
.section__head p:last-child { color: var(--ink-soft); margin-top: 16px; }
.kicker { font: 700 13px var(--sans); letter-spacing: 0.14em; text-transform: uppercase; color: var(--vermilion); margin-bottom: 14px; }
.section h2 { font-size: clamp(34px, 5vw, 60px); }
.split { display: grid; grid-template-columns: minmax(200px, 280px) minmax(0, 560px); gap: clamp(32px, 6vw, 90px); align-items: center; justify-content: center; }
.split--reverse { grid-template-columns: minmax(0, 560px) minmax(200px, 280px); }
.split--reverse .phone { order: 2; }
.split p { color: var(--ink-soft); margin-top: 18px; }
@media (max-width: 820px) {
  .split, .split--reverse { grid-template-columns: 1fr; }
  .split--reverse .phone { order: 0; }
  .phone { max-width: 240px; margin: 0 auto; }
}
.phone { margin: 0; border-radius: 34px; overflow: hidden; aspect-ratio: 660 / 1434; box-shadow: var(--shadow), 0 0 0 10px var(--paper-raised), 0 0 0 11px var(--line); }
.learn__more { margin-top: 26px; }

/* MARK: - Mini sudoku */

.play { background: var(--paper-sunken); }
.mini {
  display: grid; grid-template-columns: min(88vw, 480px) min(88vw, 300px); grid-template-areas: "board garden" "board side";
  gap: 18px clamp(24px, 4vw, 56px); justify-content: center; align-items: center;
}
.mini__garden { grid-area: garden; height: 250px; align-self: end; }
.mini__garden canvas { width: 100%; height: 100%; display: block; cursor: grab; touch-action: pan-y; }
.mini__side { grid-area: side; align-self: start; }
@media (max-width: 860px) {
  .mini { grid-template-columns: min(88vw, 480px); grid-template-areas: "garden" "board" "side"; }
  .mini__garden { height: 180px; }
}
.mini__board {
  grid-area: board; display: grid; grid-template: repeat(6, 1fr) / repeat(6, 1fr); width: min(88vw, 480px); aspect-ratio: 1;
  background: var(--paper-raised); border-radius: var(--radius); overflow: hidden; box-shadow: var(--shadow);
  border: 2px solid color-mix(in srgb, var(--ink) 55%, transparent);
}
.cell {
  border: 0; margin: 0; padding: 0; background: transparent; color: var(--ink);
  font: 500 clamp(26px, 6vw, 40px) var(--serif); cursor: pointer; position: relative;
  border-right: 1px solid var(--line); border-bottom: 1px solid var(--line);
  transition: background 0.25s;
}
.cell:nth-child(6n + 3) { border-right: 2px solid color-mix(in srgb, var(--ink) 50%, transparent); }
.cell:nth-child(6n) { border-right: 0; }
.cell:nth-child(n + 7):nth-child(-n + 12), .cell:nth-child(n + 19):nth-child(-n + 24) { border-bottom: 2px solid color-mix(in srgb, var(--ink) 50%, transparent); }
.cell:nth-child(n + 31) { border-bottom: 0; }
.cell.given { font-weight: 700; cursor: default; }
.cell.entered { color: #3a55a4; }
:root[data-theme="dark"] .cell.entered { color: #9fb4f0; }
@media (prefers-color-scheme: dark) { :root:not([data-theme="light"]) .cell.entered { color: #9fb4f0; } }
.cell.peer { background: color-mix(in srgb, var(--moss) 8%, transparent); }
.cell.same { background: color-mix(in srgb, #3a55a4 14%, transparent); }
.cell.selected { background: color-mix(in srgb, var(--gold) 28%, transparent); }
.cell.wrong { color: var(--vermilion); }
.cell.hinted { animation: hinted 1.6s ease-in-out 2; }
@keyframes hinted { 50% { background: color-mix(in srgb, var(--moss) 30%, transparent); } }
.cell.ripple::after {
  content: ""; position: absolute; inset: 15%; border-radius: 50%; border: 2px solid var(--moss);
  animation: ripple 0.9s ease-out forwards; pointer-events: none;
}
@keyframes ripple { from { transform: scale(0.4); opacity: 0.9; } to { transform: scale(1.6); opacity: 0; } }
.cell.glow { animation: glow 1s ease-out; }
@keyframes glow { 30% { background: color-mix(in srgb, var(--gold) 35%, transparent); } }
.mini__side { display: grid; gap: 18px; width: min(88vw, 300px); }
.mini__pad { display: grid; grid-template-columns: repeat(3, 1fr); gap: 10px; }
.mini__pad button {
  border: 1px solid var(--line); background: var(--paper-raised); color: var(--ink); border-radius: 16px;
  font: 500 32px var(--serif); padding: 12px 0; cursor: pointer; box-shadow: 0 4px 14px rgba(0, 0, 0, 0.06);
  transition: transform 0.15s;
}
.mini__pad button:active { transform: scale(0.95); }
.mini__pad button small { display: block; font: 600 11px var(--sans); color: var(--ink-soft); }
.mini__tools { display: flex; flex-wrap: wrap; gap: 8px; }
.mini__tools .button { padding: 10px 16px; font-size: 14px; }
.mini__message { min-height: 3em; color: var(--ink-soft); font-family: var(--serif); font-size: 19px; font-style: italic; }

/* MARK: - Patterns */

.patterns { background: var(--paper-sunken); --pt-link: #3a55a4; }
:root[data-theme="dark"] .patterns { --pt-link: #9fb4f0; }
@media (prefers-color-scheme: dark) { :root:not([data-theme="light"]) .patterns { --pt-link: #9fb4f0; } }
.pt { max-width: 1120px; margin: 0 auto; display: grid; gap: clamp(28px, 4vw, 52px); }
.pt__list { position: relative; display: grid; grid-template-columns: repeat(4, minmax(0, 1fr)); gap: 16px 28px; }
.pt__group-title, .pt__level {
  display: flex; align-items: center; gap: 8px; margin-bottom: 10px;
  font: 700 12px var(--sans); letter-spacing: 0.14em; text-transform: uppercase; color: var(--ink-soft);
}
.pt__group-title::before, .pt__level::before { content: ""; width: 8px; height: 8px; border-radius: 50%; background: var(--level); }
[data-level="easy"] { --level: var(--moss); }
[data-level="medium"] { --level: var(--gold); }
[data-level="hard"] { --level: var(--vermilion); }
[data-level="expert"] { --level: var(--ink); }
.pt__chips { display: flex; flex-wrap: wrap; gap: 8px; }
.pt__chip {
  border: 1px solid var(--line); background: var(--paper-raised); color: var(--ink); border-radius: 99px;
  padding: 7px 13px; font: 600 14px var(--sans); cursor: pointer; white-space: nowrap;
  transition: background 0.25s, color 0.25s, transform 0.2s;
}
.pt__chip:hover { transform: translateY(-1px); background: var(--paper); }
.pt__chip[aria-pressed="true"] { background: var(--ink); color: var(--paper); border-color: transparent; }
.pt__stage {
  display: grid; grid-template-columns: minmax(0, 540px) minmax(0, 400px); gap: clamp(28px, 5vw, 64px);
  justify-content: center; align-items: center;
}
.pt__figure { margin: 0; }
.pt__board {
  width: 100%; height: auto; aspect-ratio: 1; display: block; overflow: hidden; border-radius: var(--radius);
  box-shadow: var(--shadow); background: var(--paper-raised); border: 2px solid color-mix(in srgb, var(--ink) 55%, transparent);
  scroll-margin: 84px 0 16px;
}
.pt__legend { display: flex; flex-wrap: wrap; justify-content: center; gap: 6px 18px; margin-top: 14px; font-size: 13px; color: var(--ink-soft); }
.pt__key { display: inline-flex; align-items: center; gap: 7px; }
.pt__key::before { content: ""; width: 14px; height: 14px; border-radius: 50%; }
.pt__key--pattern::before { background: color-mix(in srgb, var(--gold) 60%, transparent); }
.pt__key--placed::before { background: color-mix(in srgb, var(--moss) 45%, transparent); }
.pt__key--out::before { background: linear-gradient(135deg, transparent 44%, var(--vermilion) 44% 58%, transparent 58%); border-radius: 0; }
.pt__key--strong::before, .pt__key--weak::before { width: 22px; height: 0; border-radius: 0; border-top: 3px solid var(--pt-link); }
.pt__key--weak::before { border-top-style: dashed; }
.pt__text h3 { font-size: clamp(30px, 3.6vw, 44px); }
.pt__alias { font: 600 15px var(--sans); color: var(--ink-soft); vertical-align: middle; }
.pt__lesson { margin-top: 16px; font-size: 18px; }
.pt__example { margin-top: 14px; color: var(--ink-soft); }
.pt__example strong { color: var(--ink); }
.pt__result { margin-top: 12px; font: italic 19px/1.45 var(--serif); }
.pt__replay { margin-top: 24px; }
@media (max-width: 1000px) { .pt__list { grid-template-columns: repeat(2, minmax(0, 1fr)); } }
@media (max-width: 820px) { .pt__stage { grid-template-columns: minmax(0, 540px); } }
/* Phones: the techniques become one rail that scrolls sideways above the board. */
@media (max-width: 640px) {
  .pt__list {
    display: flex; gap: 22px; overflow-x: auto; scroll-snap-type: x proximity; scroll-padding-inline: clamp(20px, 6vw, 80px); scrollbar-width: none;
    margin-inline: calc(-1 * clamp(20px, 6vw, 80px)); padding: 4px clamp(20px, 6vw, 80px) 8px;
  }
  .pt__list::-webkit-scrollbar { display: none; }
  .pt__group { flex: none; scroll-snap-align: start; }
  .pt__chips { flex-wrap: nowrap; }
}

/* The board, a 900 x 900 SVG. Stages appear in turn: houses, pattern, links, result. */
.pt-paper { fill: var(--paper-raised); }
.pt-unit--base { fill: color-mix(in srgb, var(--moss) 15%, transparent); }
.pt-unit--cover { fill: color-mix(in srgb, var(--gold) 13%, transparent); }
.pt-cell { fill: color-mix(in srgb, var(--gold) 26%, transparent); }
.pt-target { fill: color-mix(in srgb, var(--vermilion) 12%, transparent); }
.pt-placed-cell { fill: color-mix(in srgb, var(--moss) 26%, transparent); }
.pt-grid { stroke: var(--line); stroke-width: 2; }
.pt-grid--box { stroke: color-mix(in srgb, var(--ink) 55%, transparent); stroke-width: 5; }
.pt-digit { fill: var(--ink); font: 500 58px var(--serif); text-anchor: middle; dominant-baseline: central; }
.pt-digit--placed { fill: var(--moss); font-weight: 700; transform-box: fill-box; transform-origin: center; }
.pt-mark { fill: var(--ink-soft); font: 600 25px var(--sans); text-anchor: middle; dominant-baseline: central; }
.pt-mark--dim { opacity: 0.35; }
.pt-mark--key { fill: var(--ink); font-weight: 800; }
.pt-key { fill: color-mix(in srgb, var(--gold) 55%, transparent); }
.pt-blocker { fill: none; stroke: var(--gold); stroke-width: 5; }
.pt-ray { stroke: var(--gold); stroke-width: 4; stroke-dasharray: 10 9; stroke-linecap: round; }
.pt-link { stroke: var(--pt-link); stroke-width: 5; stroke-linecap: round; fill: none; }
.pt-link--strong { stroke-dasharray: 1; stroke-dashoffset: 1; }
.pt-link--weak { stroke-dasharray: 0.03 0.025; }
.pt-link--frame { stroke: var(--gold); stroke-width: 4; stroke-dasharray: 0.02 0.02; }
.pt-strike { stroke: var(--vermilion); stroke-width: 4; stroke-linecap: round; stroke-dasharray: 1; stroke-dashoffset: 1; }
.pt__board :is(.s1, .s2, .s3, .s4) { opacity: 0; transition: opacity 0.5s; }
.pt__board.play :is(.s1, .s2, .s3, .s4) { opacity: 1; }
.pt__board.play .s1 { transition-delay: 0.1s; }
.pt__board.play .s2 { transition-delay: 0.7s; }
.pt__board.play .s3 { transition-delay: 1.3s; }
.pt__board.play .s4 { transition-delay: 2.1s; }
.pt__board.play .pt-link--strong { stroke-dashoffset: 0; transition: stroke-dashoffset 0.7s 1.3s ease-in-out, opacity 0s 1.3s; }
.pt__board.play .pt-strike { stroke-dashoffset: 0; transition: stroke-dashoffset 0.35s 2.2s ease-out, opacity 0s 2.2s; }
.pt-mark--out { transition: fill 0.4s; }
.pt__board.play .pt-mark--out { fill: var(--vermilion); transition-delay: 2.1s; }
.pt__board .pt-digit--placed { transform: scale(0.5); transition: opacity 0.5s, transform 0.6s cubic-bezier(0.2, 1.5, 0.4, 1); }
.pt__board.play .pt-digit--placed { transform: none; transition-delay: 2.1s; }
.pt__board.play .pt-gone { animation: pt-gone 0.3s 2.1s forwards; }
@keyframes pt-gone { to { opacity: 0; } }
@media (prefers-reduced-motion: reduce) { .pt__board * { transition-delay: 0s !important; animation-delay: 0s !important; } }

/* MARK: - Journey and daily */

.seasons-row { display: grid; grid-template-columns: repeat(4, minmax(0, 1fr)); gap: 18px; max-width: 1180px; margin: 0 auto; }
@media (max-width: 900px) { .seasons-row { grid-template-columns: repeat(2, minmax(0, 1fr)); } }
@media (max-width: 520px) { .seasons-row { grid-template-columns: 1fr; } }
.season-card {
  border-radius: var(--radius); padding: 28px 24px 32px; min-height: 240px; border: 1px solid var(--line);
  background: linear-gradient(160deg, var(--card-top), var(--card-bottom)); box-shadow: var(--shadow);
  transition: transform 0.4s;
}
.season-card:hover { transform: translateY(-6px) rotate(-0.6deg); }
.season-card[data-season="spring"] { --card-top: #fdf0f1; --card-bottom: #f5d7dc; }
.season-card[data-season="summer"] { --card-top: #f2f7e6; --card-bottom: #d9e8c9; }
.season-card[data-season="autumn"] { --card-top: #fdf0e1; --card-bottom: #f1d0ac; }
.season-card[data-season="winter"] { --card-top: #f3f6fa; --card-bottom: #d9e2ed; }
:root[data-theme="dark"] .season-card { --card-top: #1f2644 !important; --card-bottom: #161c34 !important; }
@media (prefers-color-scheme: dark) { :root:not([data-theme="light"]) .season-card { --card-top: #1f2644 !important; --card-bottom: #161c34 !important; } }
.season-card h3 { font-size: 28px; margin-bottom: 18px; }
.haiku { font-family: var(--serif); font-style: italic; font-size: 19px; line-height: 1.6; color: var(--ink-soft); }
.countdown { font-family: var(--serif); font-size: 22px; color: var(--ink) !important; }
.countdown time { font-variant-numeric: tabular-nums; color: var(--gold); }

.film { display: grid; place-items: center; }
.film video { width: min(100%, 1100px); aspect-ratio: 16 / 9; border-radius: var(--radius); box-shadow: var(--shadow); background: var(--paper-sunken); }

.finale { text-align: center; display: grid; justify-items: center; gap: 18px; }
.finale p { color: var(--ink-soft); max-width: 40ch; }
.footer { text-align: center; padding: 40px 20px 60px; color: var(--ink-soft); font-size: 14px; }

/* MARK: - Reveal on scroll */

.reveal { opacity: 0; transform: translateY(30px); transition: opacity 0.9s, transform 0.9s cubic-bezier(0.2, 0.8, 0.2, 1); }
.reveal.in { opacity: 1; transform: none; }

@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after { animation-duration: 0.01ms !important; transition-duration: 0.01ms !important; }
  html { scroll-behavior: auto; }
}