/* Katsuyō — site identity, from the app's design tokens (DESIGN.md §2).
   和紙 washi paper, 藍 ai indigo for action, 朱 shu vermilion for brand and the 判子 stamp.
   System rounded type only: no web fonts, no scripts. */

:root {
  --bg: #fbf8f3;
  --surface: #ffffff;
  --sunk: #f1ece3;
  --border: #e6dfd3;
  --ink: #1e2230;
  --ink-muted: #6b7080;

  --ai: #3b5bdb;
  --ai-lip: #2b44a8;
  --ai-soft: #e5eaff;
  --ai-ink: #2b44a8;
  --ai-on: #ffffff;

  --shu: #f05a28;
  --shu-lip: #c2410c;
  --shu-soft: #ffe8de;
  --shu-ink: #c2410c;
  --shu-on: #ffffff;

  --take-soft: #dcf5e8;
  --take-ink: #0b7a4c;
  --kin-soft: #fff2d1;
  --kin-ink: #8a5a00;

  --font: ui-rounded, "SF Pro Rounded", "Hiragino Maru Gothic ProN", "Hiragino Sans",
          "Yu Gothic UI", "Noto Sans JP", system-ui, -apple-system, "Segoe UI", sans-serif;
  --font-ja: "Hiragino Maru Gothic ProN", "Hiragino Sans", "Yu Gothic UI", "Noto Sans JP",
             "Noto Sans CJK JP", sans-serif;

  color-scheme: light dark;
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg: #121419;
    --surface: #1c1f27;
    --sunk: #262a34;
    --border: #313645;
    --ink: #eef0f5;
    --ink-muted: #9aa0b2;

    --ai: #5c7cfa;
    --ai-lip: #3b5bdb;
    --ai-soft: #1d2650;
    --ai-ink: #a9b9ff;

    --shu: #ff7043;
    --shu-lip: #d9541f;
    --shu-soft: #3a1d12;
    --shu-ink: #ffa584;
    --shu-on: #2a0e04;

    --take-soft: #0e2e21;
    --take-ink: #6ee0ae;
    --kin-soft: #3a2c0b;
    --kin-ink: #ffd27a;
  }
}

* { box-sizing: border-box; }

body {
  margin: 0;
  background: var(--bg);
  color: var(--ink);
  font-family: var(--font);
  font-size: 17px;
  font-weight: 500;
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
  -webkit-text-size-adjust: 100%;
}

[lang="ja"] { font-family: var(--font-ja); }

.wrap { max-width: 880px; margin: 0 auto; padding: 0 20px; }

a { color: var(--ai-ink); text-underline-offset: 3px; }
a:hover { text-decoration-thickness: 2px; }

:focus-visible { outline: 3px solid var(--ai); outline-offset: 2px; border-radius: 6px; }

.skip { position: absolute; left: -9999px; }
.skip:focus { left: 16px; top: 12px; background: var(--surface); padding: 8px 12px; z-index: 1; }

h1, h2, h3 { line-height: 1.2; font-weight: 800; letter-spacing: -0.01em; }
h2 { font-size: clamp(22px, 3.6vw, 28px); margin: 0 0 14px; }
h3 { font-size: 18px; margin: 0 0 6px; }

/* ── Header / footer ────────────────────────────────────────────────── */

.site-header {
  display: flex; align-items: center; justify-content: space-between;
  flex-wrap: wrap; gap: 12px 20px; padding: 20px 0;
}

.wordmark {
  display: flex; align-items: center; gap: 10px;
  color: var(--ink); text-decoration: none; font-weight: 800; font-size: 18px;
}

/* 判子 hanko: the brand stamp. */
.hanko {
  display: inline-grid; place-items: center;
  width: 36px; height: 36px; border-radius: 9px;
  background: var(--shu); color: var(--shu-on);
  font-family: var(--font-ja); font-size: 20px; font-weight: 700;
  box-shadow: inset 0 0 0 2px var(--shu-lip);
  transform: rotate(-4deg);
}
.hanko.big { width: 76px; height: 76px; border-radius: 18px; font-size: 30px; letter-spacing: -0.02em; }

.site-nav { display: flex; gap: 18px; font-size: 15px; }
.site-nav a { color: var(--ink-muted); text-decoration: none; }
.site-nav a:hover, .site-nav a[aria-current="page"] { color: var(--ink); }

.site-footer {
  margin-top: 72px; padding: 24px 0 40px; border-top: 2px solid var(--border);
  display: flex; flex-wrap: wrap; gap: 10px 24px; justify-content: space-between;
  font-size: 14px; color: var(--ink-muted);
}
.site-footer nav { display: flex; flex-wrap: wrap; gap: 18px; }
.site-footer a { color: var(--ink-muted); }

/* ── Buttons: a lip means pressable ─────────────────────────────────── */

.btn {
  display: inline-flex; align-items: center; gap: 10px;
  padding: 14px 22px; border-radius: 16px;
  background: var(--ai); color: var(--ai-on);
  border-bottom: 4px solid var(--ai-lip);
  font-weight: 800; font-size: 19px; letter-spacing: 0.04em; text-transform: uppercase;
  text-decoration: none;
  transition: transform 150ms ease, border-bottom-width 150ms ease;
}
.btn:hover { color: var(--ai-on); }
.btn:active { transform: translateY(3px); border-bottom-width: 1px; }
.btn small { display: block; font-size: 11px; letter-spacing: 0.08em; opacity: 0.85; }

/* ── Hero ───────────────────────────────────────────────────────────── */

.hero { padding: 36px 0 8px; }
.hero .brand { display: flex; align-items: center; gap: 16px; margin-bottom: 22px; }
.hero .brand div b { display: block; font-size: 22px; }
.hero .brand div span { color: var(--ink-muted); font-size: 15px; }
.hero h1 { font-size: clamp(30px, 6vw, 50px); margin: 0 0 14px; max-width: 16ch; }
.hero h1 em { font-style: normal; color: var(--shu-ink); }
.hero .sub { color: var(--ink-muted); font-size: 18px; max-width: 56ch; margin: 0 0 24px; }
.hero .cta { display: flex; flex-wrap: wrap; align-items: center; gap: 14px 20px; }
.hero .cta p { margin: 0; color: var(--ink-muted); font-size: 14px; }

/* Signature: the godan vowel row of 書く. */
.rows {
  margin: 40px 0 0; padding: 22px 20px; border-radius: 22px;
  background: var(--surface); border: 2px solid var(--border);
}
.rows-head { display: flex; flex-wrap: wrap; align-items: baseline; gap: 4px 12px; margin-bottom: 14px; }
.rows-head h2 { font-size: 18px; margin: 0; }
.rows-head p { margin: 0; color: var(--ink-muted); font-size: 14px; }
.rows ol { list-style: none; margin: 0; padding: 0; display: grid; grid-template-columns: repeat(5, 1fr); gap: 8px; }
.rows li {
  text-align: center; padding: 12px 4px 10px; border-radius: 12px;
  background: var(--bg); border-bottom: 3px solid var(--border);
}
.rows li.dict { background: var(--ai-soft); border-color: var(--ai); }
.rows .kana { display: block; font-family: var(--font-ja); font-size: clamp(26px, 6vw, 38px); line-height: 1.2; }
.rows .row { display: block; font-size: 12px; font-weight: 700; color: var(--ink-muted); text-transform: uppercase; letter-spacing: 0.06em; }
.rows .ex { display: block; font-family: var(--font-ja); font-size: 14px; margin-top: 6px; color: var(--ai-ink); }
.rows .use { display: block; font-size: 12px; color: var(--ink-muted); line-height: 1.3; }

/* ── Sections ───────────────────────────────────────────────────────── */

section { padding: 48px 0 0; }

.eyebrow {
  margin: 0 0 6px; font-size: 13px; font-weight: 800;
  letter-spacing: 0.12em; text-transform: uppercase; color: var(--shu-ink);
}

.grid { display: grid; gap: 14px; grid-template-columns: repeat(auto-fit, minmax(240px, 1fr)); }

/* Info cards are flat: no lip. */
.card {
  background: var(--surface); border: 2px solid var(--border); border-radius: 16px;
  padding: 18px 18px 16px;
}
.card p { margin: 0; color: var(--ink-muted); font-size: 15px; }
.card .tag {
  display: inline-block; margin-bottom: 10px; padding: 2px 10px; border-radius: 999px;
  font-size: 13px; font-weight: 700; background: var(--ai-soft); color: var(--ai-ink);
}
.card .tag.shu { background: var(--shu-soft); color: var(--ink); }
.card .tag.take { background: var(--take-soft); color: var(--take-ink); }
.card .tag.kin { background: var(--kin-soft); color: var(--kin-ink); }

.drills { list-style: none; padding: 0; margin: 0; display: grid; gap: 10px; grid-template-columns: repeat(auto-fit, minmax(240px, 1fr)); }
.drills li { padding: 12px 14px; border-radius: 12px; background: var(--surface); border: 2px solid var(--border); font-size: 15px; color: var(--ink-muted); }
.drills b { display: block; color: var(--ink); font-size: 16px; }

.promise {
  display: grid; gap: 12px; grid-template-columns: repeat(auto-fit, minmax(180px, 1fr));
  margin: 0; padding: 0; list-style: none;
}
.promise li { border-left: 4px solid var(--shu); padding: 2px 0 2px 14px; }
.promise b { display: block; }
.promise span { color: var(--ink-muted); font-size: 15px; }

/* ── Document pages ─────────────────────────────────────────────────── */

.doc { max-width: 720px; }
.doc h1 { font-size: clamp(28px, 5vw, 38px); margin: 32px 0 6px; }
.doc h2 { font-size: 21px; margin: 40px 0 10px; }
.doc .updated { color: var(--ink-muted); font-size: 14px; margin: 0 0 24px; }
.doc .lede {
  background: var(--shu-soft); border-radius: 16px; padding: 16px 18px; margin: 0 0 24px;
}
.doc li { margin: 6px 0; }
.doc code { font-size: 0.92em; background: var(--sunk); padding: 1px 6px; border-radius: 6px; }

.table-wrap { overflow-x: auto; }
table { border-collapse: collapse; width: 100%; font-size: 15px; }
th, td { text-align: left; vertical-align: top; padding: 10px 12px; border-bottom: 2px solid var(--border); }
th { font-weight: 800; }

details {
  background: var(--surface); border: 2px solid var(--border); border-radius: 16px;
  padding: 2px 18px; margin: 10px 0;
}
summary {
  cursor: pointer; font-weight: 700; padding: 14px 0; list-style: none;
  display: flex; justify-content: space-between; gap: 12px;
}
summary::-webkit-details-marker { display: none; }
summary::after { content: "+"; color: var(--ai-ink); font-weight: 800; flex-shrink: 0; }
details[open] summary::after { content: "−"; }
details p, details ul { margin-top: 0; color: var(--ink-muted); }

.contact {
  margin: 36px 0 0; padding: 22px 22px; border-radius: 22px;
  background: var(--ai-soft); border: 2px solid var(--ai);
}
.contact h2 { margin: 0 0 6px; font-size: 21px; }
.contact p { margin: 6px 0; }

@media (prefers-reduced-motion: reduce) {
  .btn { transition: none; }
}

@media (max-width: 560px) {
  .rows { padding: 16px 12px; }
  .rows ol { gap: 5px; }
  .rows li { padding: 10px 2px 8px; }
  .rows .row { font-size: 10px; letter-spacing: 0; }
  .rows .ex { font-size: 11px; white-space: nowrap; }
  .rows .use { display: none; }
}