/* Ensō Sudoku: washi paper, sumi ink, indigo (藍) for the player, one vermilion (朱) accent.
   Colors mirror EnsoSudoku/Theme.swift; dark mode is ink-stone, not inverted paper. */
:root {
  --paper: #F4F1EA;
  --board-paper: #FBFAF6;
  --ink: #1F1D1B;
  --ink-secondary: #6F6B64;
  --note-ink: #7C7770;
  --player-ink: #2B4C7E;
  --grid-thin: #DDD8CE;
  --grid-thick: #3B3834;
  --seal: #C0402C;
  --grain-opacity: .07;
  --serif: ui-serif, "New York", "Iowan Old Style", Georgia, "Times New Roman", serif;
  --mincho: "Hiragino Mincho ProN", "Yu Mincho", "YuMincho", "Noto Serif JP", "Noto Serif CJK JP", serif;
  --sans: -apple-system, BlinkMacSystemFont, "Segoe UI", system-ui, sans-serif;
  color-scheme: light dark;
}
@media (prefers-color-scheme: dark) {
  :root {
    --paper: #151413;
    --board-paper: #1D1C1A;
    --ink: #EAE6DE;
    --ink-secondary: #A29D94;
    --note-ink: #8E897F;
    --player-ink: #92ACD8;
    --grid-thin: #2F2D2A;
    --grid-thick: #8A857C;
    --seal: #E47561;
    --grain-opacity: .05;
  }
}

* { box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; }
body {
  margin: 0;
  background: var(--paper);
  color: var(--ink);
  font: 17px/1.6 var(--sans);
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}
/* Barely-there paper grain, like printed stock. */
body::before {
  content: "";
  position: fixed;
  inset: 0;
  pointer-events: none;
  opacity: var(--grain-opacity);
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='160' height='160'%3E%3Cfilter id='n'%3E%3CfeTurbulence type='fractalNoise' baseFrequency='.85' numOctaves='3' stitchTiles='stitch'/%3E%3CfeColorMatrix type='saturate' values='0'/%3E%3C/filter%3E%3Crect width='100%25' height='100%25' filter='url(%23n)'/%3E%3C/svg%3E");
  mix-blend-mode: multiply;
}
@media (prefers-color-scheme: dark) { body::before { mix-blend-mode: screen; } }

a { color: var(--player-ink); text-underline-offset: 3px; text-decoration-thickness: 1px; }
a:hover { text-decoration-thickness: 2px; }
:focus-visible { outline: 2px solid var(--player-ink); outline-offset: 3px; border-radius: 2px; }

.wrap { width: 100%; max-width: 680px; margin: 0 auto; padding: 0 20px; }
main { flex: 1; }

/* Header */
.site-header { padding: 22px 0; }
.site-header .wrap { display: flex; align-items: center; justify-content: space-between; gap: 16px; }
.brand { display: flex; align-items: center; gap: 10px; color: var(--ink); text-decoration: none; font: 600 19px/1 var(--serif); }
.brand img { width: 30px; height: 30px; border-radius: 7px; }
.site-header nav { display: flex; gap: 20px; font-size: 15px; }
.site-header nav a { color: var(--ink-secondary); text-decoration: none; }
.site-header nav a:hover, .site-header nav a[aria-current] { color: var(--ink); }

/* Seal */
.seal {
  display: inline-grid; place-items: center;
  width: 48px; height: 48px; border-radius: 7px;
  background: var(--seal); color: var(--board-paper);
  font: 600 30px/1 var(--mincho);
}

/* Home hero */
.hero { text-align: center; padding-block: 32px 56px; }
.enso {
  position: relative;
  width: min(300px, 72vw); aspect-ratio: 1; margin: 0 auto 28px;
}
.enso::before {
  content: ""; position: absolute; inset: 0;
  background: var(--ink);
  -webkit-mask: url("assets/enso.png") center / contain no-repeat;
          mask: url("assets/enso.png") center / contain no-repeat;
}
.enso .seal { position: absolute; right: 6%; bottom: 8%; }
h1 { font: 600 clamp(36px, 7vw, 48px)/1.1 var(--serif); margin: 0; letter-spacing: -.01em; }
.kanji { font-family: var(--mincho); color: var(--ink-secondary); letter-spacing: .4em; margin: 10px 0 0 .4em; font-size: 16px; }
.tagline { color: var(--ink-secondary); font-size: 19px; margin: 14px 0 30px; }
.store-badge {
  display: inline-flex; align-items: center; gap: 10px;
  padding: 11px 22px; border-radius: 12px;
  background: var(--ink); color: var(--paper);
  font: 500 16px/1 var(--sans); text-decoration: none;
}
.store-badge svg { width: 18px; height: 18px; fill: currentColor; }
.store-badge[aria-disabled="true"] { background: transparent; color: var(--ink-secondary); border: 1px solid var(--grid-thin); cursor: default; }

/* Screenshot gallery: full-bleed strip that scrolls sideways when it doesn't fit. */
.gallery { margin: 0 0 64px; }
.shots {
  display: flex; gap: 22px;
  overflow-x: auto; scroll-snap-type: x mandatory; scrollbar-width: none;
  padding: 8px max(20px, calc((100vw - 1340px) / 2)) 16px;
}
.shots::-webkit-scrollbar { display: none; }
.shots figure { flex: none; width: 240px; margin: 0; scroll-snap-align: center; }
.shots img {
  display: block; width: 100%; height: auto;
  border: 1px solid var(--grid-thin);
  border-radius: 30px;
  box-shadow: 0 18px 40px -24px rgba(0,0,0,.35);
}
.shots figcaption { text-align: center; color: var(--ink-secondary); font-size: 14px; margin-top: 12px; }
@media (min-width: 1360px) { .shots { justify-content: center; } }

/* Sections */
.section { padding-block: 8px 48px; }
h2 { font: 600 26px/1.25 var(--serif); margin: 0 0 18px; }
h3 { font: 600 19px/1.3 var(--serif); margin: 28px 0 6px; }
.rule { border: 0; height: 1px; background: var(--grid-thin); margin: 0 0 48px; }

.features { list-style: none; padding: 0; margin: 0; display: grid; gap: 22px; }
.features li { display: grid; grid-template-columns: 28px 1fr; gap: 14px; }
.features .mark { font: 600 18px/1.6 var(--mincho); color: var(--seal); text-align: center; }
.features strong { font: 600 18px/1.4 var(--serif); display: block; }
.features p { margin: 2px 0 0; color: var(--ink-secondary); }

.tiers { display: grid; grid-template-columns: repeat(4, 1fr); gap: 10px; margin-top: 8px; }
.tier { text-align: center; padding: 14px 6px; border: 1px solid var(--grid-thin); border-radius: 10px; background: var(--board-paper); }
.tier span { display: block; font: 600 22px/1.2 var(--mincho); }
.tier small { color: var(--ink-secondary); font-size: 14px; }

/* Prose pages */
.page { padding-block: 24px 64px; }
.page h1 { font-size: clamp(32px, 6vw, 40px); margin-bottom: 6px; }
.page .meta { color: var(--ink-secondary); font-size: 15px; margin: 0 0 32px; }
.page .lede { font: 400 20px/1.55 var(--serif); margin: 0 0 8px; }
.page p, .page li { color: var(--ink); }
.page ul { padding-left: 1.2em; }
.page li { margin: 6px 0; }
.callout {
  border-left: 3px solid var(--seal);
  background: var(--board-paper);
  padding: 14px 18px; margin: 24px 0; border-radius: 0 8px 8px 0;
}
.callout p { margin: 0; }
details { border-bottom: 1px solid var(--grid-thin); padding: 14px 0; }
details summary { cursor: pointer; font: 600 18px/1.4 var(--serif); list-style: none; display: flex; justify-content: space-between; gap: 12px; }
details summary::-webkit-details-marker { display: none; }
details summary::after { content: "+"; color: var(--ink-secondary); font-family: var(--sans); font-weight: 400; }
details[open] summary::after { content: "−"; }
details p { margin: 10px 0 0; color: var(--ink-secondary); }

/* Footer */
.site-footer { padding: 28px 0 36px; color: var(--ink-secondary); font-size: 14px; }
.site-footer .wrap { display: flex; flex-wrap: wrap; gap: 8px 20px; justify-content: space-between; border-top: 1px solid var(--grid-thin); padding-top: 22px; }
.site-footer nav { display: flex; gap: 18px; }
.site-footer a { color: var(--ink-secondary); text-decoration: none; }
.site-footer a:hover { color: var(--ink); }

@media (max-width: 480px) {
  .site-header nav { gap: 14px; }
  .tiers { grid-template-columns: repeat(2, 1fr); }
}