/* オルカンに勝てん！ フロントページ
   表紙の「夕暮れの丸の内」から、ビューアの「紙」の色へつながる配色。外部フォント・外部スクリプトなし。 */
:root {
  color-scheme: light;
  --dusk: #1f1d33;        /* 表紙の空の濃紺 */
  --dusk-2: #2c2a48;
  --lamp: #e7b46a;        /* 街灯の金色 */
  --lamp-ink: #2a1e10;
  --cream: #f7eedd;       /* 夕暮れの文字色 */
  --cream-dim: #cdbfa8;
  --paper: #f6f4ed;       /* ビューアと同じ紙色 */
  --ink: #243746;         /* ビューアと同じ文字色 */
  --muted: #62707a;
  --line: #d7d9d4;
  --blue: #1f43b8;        /* 怜先生のブラウスの青 */
  --mincho: "Yu Mincho", "YuMincho", "Hiragino Mincho ProN", "Noto Serif JP", "Noto Serif CJK JP", serif;
  --gothic: system-ui, -apple-system, "Segoe UI", "Noto Sans JP", "Hiragino Kaku Gothic ProN", Meiryo, sans-serif;
  font-family: var(--gothic);
  font-size: 16px;
  line-height: 1.8;
  color: var(--ink);
  background: var(--paper);
}
* { box-sizing: border-box; }
body { margin: 0; background: var(--paper); }
img { display: block; max-width: 100%; height: auto; }
[hidden] { display: none !important; }
a { color: var(--blue); text-underline-offset: .22em; }
a:focus-visible { outline: 3px solid var(--lamp); outline-offset: 3px; border-radius: 4px; }

.skip {
  position: absolute; left: 12px; top: -60px; z-index: 10;
  background: var(--lamp); color: var(--lamp-ink); padding: 10px 16px; border-radius: 6px; font-weight: 700;
}
.skip:focus { top: 12px; }

/* ───────── 夕暮れの帯（ヘッダー＋表紙） ───────── */
.masthead, .hero { background: var(--dusk); color: var(--cream); }
.masthead { padding: 18px 20px 0; }
.masthead-label {
  max-width: 1040px; margin: 0 auto;
  font-size: .78rem; letter-spacing: .18em; color: var(--cream-dim);
}

.hero {
  position: relative;
  padding: 28px 20px 64px;
  background:
    radial-gradient(120% 70% at 50% 108%, rgba(231,180,106,.38), transparent 60%),
    linear-gradient(180deg, var(--dusk) 0%, var(--dusk-2) 62%, #4a3a4a 100%);
  display: grid;
  gap: 36px;
  justify-items: center;
}
/* 紙へ移るところを、本の小口のように細い線で区切る */
.hero::after {
  content: ""; position: absolute; left: 0; right: 0; bottom: 0; height: 6px;
  background: linear-gradient(180deg, rgba(231,180,106,.55), rgba(231,180,106,0));
}

.hero-book {
  display: flex; align-items: flex-start; gap: 18px;
  width: 100%; max-width: 440px; justify-content: center;
}
.cover {
  flex: 0 1 300px;
  border-radius: 4px;
  box-shadow: 0 2px 0 rgba(255,255,255,.08), 0 24px 50px rgba(0,0,0,.45), 0 0 0 1px rgba(255,255,255,.06);
  transition: transform .25s ease, box-shadow .25s ease;
  animation: arrive .7s ease-out both;
}
/* 表紙画像の左右の白い余白（各31px/1200px）を隠す */
.cover { display: block; overflow: hidden; aspect-ratio: 1138 / 1698; }
.cover img { width: 105.45%; max-width: none; margin-left: -2.72%; }
.cover:hover { transform: translateY(-3px); box-shadow: 0 30px 60px rgba(0,0,0,.5), 0 0 0 1px rgba(231,180,106,.35); }

/* 表紙の横に置く縦書きのキャッチコピー */
.catch {
  margin: 4px 0 0;
  writing-mode: vertical-rl;
  font-family: var(--mincho);
  font-weight: 700;
  font-size: clamp(1.15rem, 5.4vw, 1.75rem);
  line-height: 1.75;
  letter-spacing: .14em;
  color: var(--cream);
  text-shadow: 0 1px 12px rgba(0,0,0,.35);
  animation: arrive .7s .15s ease-out both;
}

.catch-flat {
  position: absolute; width: 1px; height: 1px; overflow: hidden; clip: rect(0 0 0 0); white-space: nowrap;
}

.hero-text { width: 100%; max-width: 440px; }
.hero h1 {
  font-family: var(--mincho);
  font-size: clamp(1.9rem, 7vw, 2.6rem);
  font-weight: 800; line-height: 1.3; letter-spacing: .03em;
  margin: 0 0 6px;
}
.meta { margin: 0 0 26px; font-size: .86rem; color: var(--cream-dim); }
.meta span { padding: 0 .4em; opacity: .7; }

.actions { display: grid; gap: 12px; scroll-margin-top: 16px; }
.btn {
  display: grid; gap: 2px;
  padding: 14px 18px;
  border-radius: 10px;
  text-decoration: none;
  transition: background .2s ease, border-color .2s ease, transform .15s ease;
}
.btn:active { transform: translateY(1px); }
.btn-label { font-weight: 700; font-size: 1.06rem; letter-spacing: .04em; }
.btn-note { font-size: .78rem; line-height: 1.6; }

.btn-primary { background: var(--lamp); color: var(--lamp-ink); box-shadow: 0 8px 24px rgba(231,180,106,.25); }
.btn-primary .btn-label::after { content: "  →"; }
.btn-primary .btn-note { color: #5a4326; }
.btn-primary:hover { background: #f0c27e; }

.btn-quiet {
  padding: 8px 4px; color: var(--cream);
}
.btn-quiet .btn-label { font-size: .88rem; font-weight: 600; text-decoration: underline; text-underline-offset: .25em; }

.btn-secondary {
  border: 1px solid rgba(247,238,221,.35);
  color: var(--cream);
  background: rgba(255,255,255,.03);
}
.btn-secondary .btn-label { font-size: .96rem; }
.btn-secondary .btn-label::after { content: "  ↓"; color: var(--lamp); }
.btn-secondary .btn-note { color: var(--cream-dim); }
.btn-secondary:hover { border-color: var(--lamp); background: rgba(231,180,106,.08); }

/* ───────── 紙のセクション ───────── */
main > section:not(.hero) {
  max-width: 760px; margin: 0 auto; padding: 56px 20px 0;
}
.section-title {
  display: flex; align-items: center; gap: 12px;
  font-family: var(--mincho);
  font-size: 1.25rem; font-weight: 700; letter-spacing: .08em;
  margin: 0 0 18px;
}
.section-title::before {
  content: ""; width: 22px; height: 2px; background: var(--lamp); flex: none;
}

.about-text p, .note-text p { margin: 0 0 1em; }
.about-text { font-size: 1.02rem; }
.about-text p:first-child {
  font-family: var(--mincho); font-size: 1.12rem; line-height: 1.9;
}
.about-text .about-question {
  font-family: var(--mincho); font-weight: 700; font-size: 1.3rem; letter-spacing: .06em;
  margin: 1.4em 0; padding-left: .2em;
}

/* 最初の数ページ */
.peek-row {
  list-style: none; margin: 0; padding: 4px 2px 12px;
  display: grid; grid-auto-flow: column; grid-auto-columns: minmax(150px, 1fr);
  gap: 14px; overflow-x: auto; scroll-snap-type: x mandatory;
}
.peek-row li { scroll-snap-align: start; }
.peek-row a { display: block; text-decoration: none; color: var(--muted); }
.peek-row img {
  background: #fff; border-radius: 2px;
  box-shadow: 0 1px 2px rgba(36,55,70,.08), 0 8px 22px rgba(36,55,70,.10);
  transition: transform .2s ease, box-shadow .2s ease;
}
.peek-row a:hover img { transform: translateY(-3px); box-shadow: 0 14px 30px rgba(36,55,70,.16); }
.peek-row span { display: block; margin-top: 8px; font-size: .78rem; letter-spacing: .06em; font-variant-numeric: tabular-nums; }
.peek-more { margin: 6px 0 0; text-align: right; font-weight: 600; }

/* 目次 */
.toc-cols { display: grid; gap: 28px; }
.toc h3 {
  font-size: .8rem; letter-spacing: .16em; color: var(--muted); font-weight: 600; margin: 0 0 4px;
}
.toc ol { list-style: none; margin: 0; padding: 0; }
.toc li { border-bottom: 1px solid var(--line); }
.toc li a {
  display: flex; justify-content: space-between; align-items: baseline; gap: 16px;
  padding: 11px 2px; min-height: 48px;
  color: var(--ink); text-decoration: none; font-size: .93rem; line-height: 1.5;
}
.toc li a:hover { color: var(--blue); }
.toc small { color: var(--muted); font-size: .76rem; font-variant-numeric: tabular-nums; flex: none; }
.toc-note { font-size: .8rem; color: var(--muted); margin: 14px 0 0; }

/* 作者から */
.note-text {
  font-family: var(--mincho);
  font-size: 1.02rem; line-height: 2;
  padding-left: 18px; border-left: 2px solid var(--line);
}
.sign { text-align: right; font-family: var(--mincho); font-weight: 700; letter-spacing: .12em; margin: 4px 0 0; }

/* フッター */
.footer {
  margin-top: 72px; padding: 32px 20px 48px;
  border-top: 1px solid var(--line);
  text-align: center; font-size: .78rem; color: var(--muted);
}
.footer p { margin: 6px auto; max-width: 640px; }
.footer-read { font-size: .92rem; margin-bottom: 18px !important; }
.footer-read span { padding: 0 .6em; }

/* ───────── 広い画面 ───────── */
@media (min-width: 880px) {
  .masthead { padding: 26px 40px 0; }
  .hero {
    grid-template-columns: auto minmax(0, 400px);
    justify-content: center; align-items: center;
    gap: 64px; padding: 36px 40px 84px;
  }
  .hero-book { max-width: none; width: auto; gap: 26px; }
  .cover { flex-basis: 360px; width: 360px; }
  .catch { font-size: 1.9rem; margin-top: 10px; }
  .hero-text { max-width: 400px; }
  main > section:not(.hero) { padding-top: 76px; }
  .toc-cols { grid-template-columns: 1fr 1fr; gap: 40px; }
  .peek-row { grid-auto-columns: 1fr; overflow: visible; }
}

/* とても狭い画面：縦書きが窮屈なら表紙の下へ */
@media (max-width: 340px) {
  .hero-book { flex-direction: column; align-items: center; }
  .catch { writing-mode: horizontal-tb; text-align: center; }
  .catch br { display: none; }
}

@keyframes arrive { from { opacity: 0; transform: translateY(10px); } to { opacity: 1; transform: none; } }
@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after { animation: none !important; transition: none !important; }
}