/* =========================================================
   CONTENTS PAGE / COLOR SETTINGS
   次巻へ流用するときは、まずこのブロックだけ確認してください。
   ========================================================= */
:root {
  /* ===== 背景 ===== */

  --color-bg: #07090a;
  /* ページ全体とHEROの基本背景。
     各セクションの最も暗い基準色にも使います。 */

  --color-bg-deep: #050607;
  /* フッター、ゲーム画面の余白、最暗部に使う背景色。 */

  --color-surface: #0b0e10;
  /* カード、比較表、ボタンなど「背景の上に載る面」の色。 */


  /* ===== 文字 ===== */

  --color-text: #f1eee8;
  /* 見出し、価格、主要テキスト、ボタン文字などの基本文字色。 */

  --color-text-soft: #c9c5be;
  /* あらすじ・説明文・フッター作品名など、本文向けの落ち着いた文字色。 */

  --color-text-muted: #8c9193;
  /* ナビ、注記、比較表ラベルなど補助情報の文字色。 */


  /* ===== 線・枠 ===== */

  --color-line: #293035;
  /* セクション境界、カード内部、比較表の横線などの基本ライン。 */

  --color-line-strong: #3a4348;
  /* 画像枠、カード外枠、比較表外枠、ライトボックス画像枠など強めのライン。 */


  /* ===== 巻ごとのテーマ色 ===== */

  --color-season: #8fa4ad;
  /* 巻の空気感を担う補助色。
     ヘッダー線、体験版側、補助文字、薄い背景色などに広く反映。 */

  --color-accent: #d87a1f;
  /* 巻の主アクセント色。
     HERO英字、製品版側、注意書きライン、販売ボタンなどに使用。 */

  --color-accent-soft: #d99553;
  /* アクセントの明るい色。
     見出しシンボル、製品版の数値・ラベルなどに使用。 */


  /* ===== 固定色：通常は変更しない ===== */

  --color-white: #ffffff;
  /* hover時などの完全な白。 */

  --color-black: #000000;
  /* シャドウ、暗幕、ライトボックス背景などの基準色。 */
}

/* =========================================================
   LAYOUT / TYPOGRAPHY
   ここから下は巻をまたいで共通利用する想定です。
   ========================================================= */
:root {
  --max: 1160px;
  --current-hero-height: min(820px, calc(100vh - 58px));
  --current-title-width: 900px;
  --current-bg-position: center 15%;
  --current-hero-padding-top: 36px;
  --current-hero-padding-bottom: 36px;
  --current-content-offset-y: -20px;
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  background:
    radial-gradient(circle at 78% 8%, color-mix(in srgb, var(--color-season) 9%, transparent), transparent 25%),
    linear-gradient(180deg, var(--color-bg) 0%, var(--color-surface) 35%, var(--color-bg-deep) 100%);
  color: var(--color-text);
  font-family: "Yu Mincho","Hiragino Mincho ProN","Noto Serif JP",serif;
  letter-spacing: .035em;
  font-size: 18px;
  line-height: 2;
}

a {
  color: inherit;
}

img {
  display: block;
  max-width: 100%;
}

button {
  font: inherit;
}

.svg-sprite {
  position: absolute;
  overflow: hidden;
}

.wrap {
  width: min(var(--max), calc(100% - 44px));
  margin: auto;
}

/* ===== HEADER ===== */
.site-header {
  position: sticky;
  top: 0;
  z-index: 50;
  background: color-mix(in srgb, var(--color-bg) 92%, transparent);
  backdrop-filter: blur(9px);
  border-bottom: 1px solid color-mix(in srgb, var(--color-season) 20%, transparent);
}

.header-inner {
  min-height: 58px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 24px;
}

.back,
.header-links a {
  text-decoration: none;
  letter-spacing: .06em;
}

.back {
  color: color-mix(in srgb, var(--color-text) 74%, var(--color-season));
  font-size: 18px;
}

.back:hover,
.header-links a:hover {
  color: var(--color-white);
}

.header-links {
  display: flex;
  gap: 18px;
  align-items: center;
}

.header-links a {
  color: color-mix(in srgb, var(--color-text-muted) 78%, var(--color-season));
  font-size: 17px;
}

/* ===== HERO ===== */
.hero.hero-centered {
  position: relative;
  min-height: var(--current-hero-height);
  display: flex;
  align-items: center;
  overflow: hidden;
  isolation: isolate;
  border-bottom: 1px solid var(--color-line);
  background: var(--color-bg);
}

.hero.hero-centered::before {
  content: "";
  position: absolute;
  inset: 0;
  z-index: -3;
  background:
    url("../assets/umikara/umikara-hero-bg.webp")
    var(--current-bg-position) / cover no-repeat;
}

.hero.hero-centered::after {
  content: "";
  position: absolute;
  inset: 0;
  z-index: -2;
  background: color-mix(in srgb, var(--color-bg) 68%, transparent);
}

.hero.hero-centered .hero-inner::before {
  content: "";
  position: absolute;
  left: 50%;
  top: 50%;
  width: min(900px, 90vw);
  height: 82%;
  transform: translate(-50%, -50%);
  z-index: -1;
  pointer-events: none;
  background: radial-gradient(
    ellipse at center,
    color-mix(in srgb, var(--color-black) 30%, transparent) 0%,
    color-mix(in srgb, var(--color-black) 12%, transparent) 54%,
    transparent 80%
  );
}

.hero.hero-centered .hero-inner {
  position: relative;
  width: min(var(--max), calc(100% - 44px));
  min-height: var(--current-hero-height);
  margin: 0 auto;
  padding: var(--current-hero-padding-top) 0 var(--current-hero-padding-bottom);
  display: flex;
  align-items: center;
  justify-content: center;
}

.hero.hero-centered .hero-copy-wrap {
  transform: translateY(var(--current-content-offset-y));
  position: relative;
  z-index: 1;
  width: min(920px, 100%);
  margin: 0 auto;
  text-align: center;
  display: flex;
  flex-direction: column;
  align-items: center;
}

.book-label {
  margin-bottom: 5px;
  color: var(--color-accent);
  font: 700 17px/1.45 Arial,sans-serif;
  letter-spacing: .16em;
}

.hero-series {
  margin-bottom: 4px;
  color: color-mix(in srgb, var(--color-text-muted) 80%, var(--color-season));
  letter-spacing: .12em;
  font-size: 20px;
  line-height: 1.6;
}

.hero-volume-meta {
  position: relative;
  z-index: 2;
  display: flex;
  flex-direction: column;
  align-items: center;
  margin-bottom: 8px;
  opacity: 1;
  visibility: visible;
}

.hero-title-text {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0,0,0,0);
  white-space: nowrap;
  border: 0;
}

.hero-title-art {
  width: min(var(--current-title-width), 82vw);
  margin: 4px auto 12px;
}

.hero-title-art img {
  width: 100%;
  height: auto;
  object-fit: contain;
  filter: drop-shadow(0 4px 18px color-mix(in srgb, var(--color-black) 42%, transparent));
}

.hero-lead {
  max-width: 780px;
  margin: 0 auto;
  color: color-mix(in srgb, var(--color-text) 50%, var(--color-text-soft));
  text-align: center;
  font-size: clamp(19px,2.15vw,26px);
  line-height: 2.05;
  text-shadow: 0 2px 10px color-mix(in srgb, var(--color-black) 72%, transparent);
}

/* ===== SECTIONS / HEADINGS ===== */
section:not(.hero) {
  padding: 94px 0;
  border-bottom: 1px solid var(--color-line);
}

.section-head {
  display: grid;
  grid-template-columns: 78px 1fr;
  gap: 18px;
  align-items: start;
  margin-bottom: 42px;
}

.section-icon {
  width: 72px;
  height: 72px;
  display: grid;
  place-items: center;
  margin-top: 0;
  color: var(--color-accent-soft);
}

.section-icon svg {
  width: 62px;
  height: 62px;
}

h2 {
  margin: 0 0 12px;
  color: var(--color-text);
  font-weight: 500;
  letter-spacing: .05em;
  font-size: clamp(40px,5.2vw,62px);
  line-height: 1.3;
}

.section-lead {
  margin: 0;
  max-width: 860px;
  color: color-mix(in srgb, var(--color-text-muted) 84%, var(--color-season));
  font-size: clamp(18px,1.55vw,22px);
  line-height: 1.95;
}

/* ===== THIS BOOK ===== */
.about-book {
  background: linear-gradient(
    180deg,
    color-mix(in srgb, var(--color-surface) 92%, var(--color-season)),
    var(--color-bg)
  );
  padding-bottom: 72px;
}

.about-book-copy {
  width: calc(100% - 96px);
  margin: 0 0 0 96px;
  color: var(--color-text-soft);
  font-size: clamp(18px,1.5vw,22px);
  line-height: 2.05;
  letter-spacing: .035em;
}

/* ===== GALLERY ===== */
.book-gallery {
  background:
    radial-gradient(circle at 82% 10%, color-mix(in srgb, var(--color-accent) 4%, transparent), transparent 25%),
    var(--color-bg);
}

.gallery-grid {
  display: grid;
  grid-template-columns: repeat(6, minmax(0,1fr));
  gap: 16px;
  align-items: start;
}

.gallery-card {
  margin: 0;
  position: relative;
  overflow: hidden;
  border: 1px solid var(--color-line-strong);
  background: var(--color-surface);
  box-shadow: 0 16px 36px color-mix(in srgb, var(--color-black) 20%, transparent);
  cursor: zoom-in;
}

.gallery-card--portrait {
  grid-column: span 2;
}

.gallery-card--wide {
  grid-column: span 3;
}

.gallery-card img {
  width: 100%;
  height: auto;
  transition: transform .28s ease, filter .28s ease;
}

.gallery-card--portrait img {
  aspect-ratio: 2 / 3;
  object-fit: cover;
}

.gallery-card--wide img {
  aspect-ratio: 16 / 9;
  object-fit: contain;
  background: var(--color-bg-deep);
}

.gallery-card:hover img,
.gallery-card:focus-visible img {
  transform: scale(1.012);
  filter: brightness(1.04);
}

.gallery-card:focus-visible {
  outline: 1px solid var(--color-accent-soft);
  outline-offset: 4px;
}

/* ===== PURCHASE =====
   体験版側の濃色は --color-season から自動生成。
   販売ボタンの濃色は --color-accent から自動生成。
   次巻で専用の「濃い色」を別途指定する必要はありません。
   ===== */
.purchase {
  background: linear-gradient(
    180deg,
    color-mix(in srgb, var(--color-surface) 92%, var(--color-season)),
    var(--color-bg)
  );
}

.purchase-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 18px;
  align-items: stretch;
}

.purchase-box {
  position: relative;
  min-height: 390px;
  display: flex;
  flex-direction: column;
  border: 1px solid var(--color-line-strong);
  padding: 34px 38px 30px;
  background:
    linear-gradient(
      180deg,
      color-mix(in srgb, var(--color-season) 4%, transparent),
      transparent 28%
    ),
    var(--color-surface);
  overflow: hidden;
}

.purchase-box::before {
  content: "";
  position: absolute;
  top: 0;
  left: 0;
  width: 180px;
  height: 3px;
  background: linear-gradient(90deg,color-mix(in srgb, var(--color-season) 70%, var(--color-bg)),transparent);
}

.purchase-box--full::before {
  background: linear-gradient(90deg,var(--color-accent),transparent);
}

.edition-label {
  display: inline-flex;
  align-self: flex-start;
  align-items: center;
  min-height: 30px;
  padding: 0 12px;
  margin-bottom: 22px;
  border-left: 2px solid var(--color-season);
  background: color-mix(in srgb, color-mix(in srgb, var(--color-season) 70%, var(--color-bg)) 10%, transparent);
  color: color-mix(in srgb, var(--color-season) 86%, var(--color-text));
  font: 700 16px/1.4 Arial,sans-serif;
  letter-spacing: .16em;
}

.purchase-box--full .edition-label {
  border-left-color: var(--color-accent);
  background: color-mix(in srgb, var(--color-accent) 7%, transparent);
  color: var(--color-accent-soft);
}

.purchase-box h3 {
  margin: 0 0 16px;
  color: var(--color-text);
  font-weight: 500;
  letter-spacing: .05em;
  font-size: clamp(30px,2.8vw,36px);
  line-height: 1.4;
}

.purchase-box p {
  margin: 0;
  max-width: 560px;
  color: color-mix(in srgb, var(--color-text-soft) 80%, var(--color-season));
  font-size: clamp(17px,1.4vw,20px);
  line-height: 2.05;
}

.purchase-footer {
  margin-top: auto;
  padding-top: 26px;
  border-top: 1px solid var(--color-line);
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 22px;
}

.purchase-status {
  color: var(--color-text);
  font-weight: 600;
  letter-spacing: .04em;
  white-space: nowrap;
  font-size: 17px;
}

.purchase-price {
  color: var(--color-text);
  font: 700 28px/1 Arial,sans-serif;
  white-space: nowrap;
}

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  text-align: center;
  min-width: 236px;
  min-height: 60px;
  padding: 0 22px;
  text-decoration: none;
  border: 1px solid color-mix(in srgb, var(--color-season) 45%, var(--color-line-strong));
  color: var(--color-text);
  background: var(--color-surface);
  font: 700 16px/1.35 Arial,sans-serif;
  letter-spacing: .06em;
}

.btn:hover {
  border-color: var(--color-season);
  color: var(--color-white);
}

.btn--store {
  background: color-mix(in srgb, var(--color-accent) 85%, var(--color-bg));
  border-color: var(--color-accent);
  color: var(--color-white);
}

/* ===== VERSION COMPARISON ===== */
.edition-compare {
  margin-top: 46px;
  padding-top: 38px;
  border-top: 1px solid var(--color-line-strong);
}

.edition-compare__label {
  margin-bottom: 8px;
  color: var(--color-text-muted);
  font: 700 12px/1.4 Arial,sans-serif;
  letter-spacing: .16em;
}

.edition-compare__head h3 {
  margin: 0 0 10px;
  color: var(--color-text);
  font-size: clamp(26px,2.8vw,36px);
  line-height: 1.45;
  font-weight: 500;
  letter-spacing: .05em;
}

.edition-compare__head p {
  max-width: none;
  margin: 0;
  color: color-mix(in srgb, var(--color-text-muted) 88%, var(--color-season));
  font-size: 20px;
  line-height: 1.95;
}

.edition-compare__table-wrap {
  overflow-x: auto;
  border-top: 1px solid var(--color-line-strong);
  border-bottom: 1px solid var(--color-line-strong);
  background:
    linear-gradient(
      180deg,
      color-mix(in srgb, var(--color-season) 3%, transparent),
      transparent 32%
    ),
    var(--color-surface);
}

.edition-compare__table {
  width: 100%;
  min-width: 640px;
  border-collapse: collapse;
  table-layout: fixed;
  font-size: 16px;
}

.edition-compare__table th,
.edition-compare__table td {
  padding: 17px 20px;
  border-bottom: 1px solid var(--color-line);
  text-align: center;
  vertical-align: middle;
}

.edition-compare__table thead th {
  color: color-mix(in srgb, var(--color-text-soft) 82%, var(--color-season));
  font-size: 18px;
  font-weight: 500;
  letter-spacing: .08em;
}

.edition-compare__table thead th:first-child {
  width: 28%;
  text-align: left;
  color: var(--color-text-muted);
}

.edition-compare__table tbody th {
  text-align: left;
  color: color-mix(in srgb, var(--color-text-soft) 72%, var(--color-season));
  font-size: 22px;
  font-weight: 400;
}

.edition-compare__table tbody td {
  color: var(--color-text-soft);
}

.edition-compare__table tbody tr:last-child th,
.edition-compare__table tbody tr:last-child td {
  border-bottom: 0;
}

.edition-compare__table strong {
  font-size: 20px;
  font-weight: 600;
  letter-spacing: .025em;
}

.edition-compare__table thead th:nth-child(2),
.edition-compare__table tbody td:nth-child(2) strong {
  color: var(--color-season);
}

.edition-compare__table thead th:nth-child(3),
.edition-compare__table tbody td:nth-child(3) strong {
  color: var(--color-accent-soft);
}

.edition-compare__note {
  margin-top: 18px;
  padding: 17px 20px 18px;
  border-left: 2px solid var(--color-accent);
  background: linear-gradient(
    90deg,
    color-mix(in srgb, var(--color-accent) 7%, transparent),
    transparent 80%
  );
}

.edition-compare__note p {
  margin: 0;
}

.edition-compare__note-main,
.edition-compare__note-main strong {
  color: color-mix(in srgb, var(--color-text-soft) 88%, var(--color-accent-soft));
  font-size: 20px;
  line-height: 1.9;
}

.edition-compare__note-main strong {
  color: var(--color-accent-soft);
  font-weight: 500;
}

.edition-compare__note-main + p {
  margin-top: 5px;
  color: var(--color-text-muted);
  font-size: 18px;
  line-height: 1.9;
}

.guide-link {
  margin-top: 26px;
  color: color-mix(in srgb, var(--color-text-soft) 80%, var(--color-season));
  font-size: 19px;
  line-height: 1.9;
}

.guide-link a {
  color: color-mix(in srgb, var(--color-text) 86%, var(--color-season));
  text-underline-offset: 3px;
}

/* ===== FOOTER ===== */
footer {
  background: var(--color-bg-deep);
  color: color-mix(in srgb, var(--color-text-muted) 82%, var(--color-bg-deep));
  padding: 38px 0 48px;
}

.footer-inner {
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: 30px;
}

.footer-book {
  color: var(--color-text-soft);
  font-size: 18px;
  line-height: 1.7;
}

.footer-links {
  display: flex;
  flex-wrap: wrap;
  gap: 20px;
}

.footer-links a {
  text-decoration: none;
  color: color-mix(in srgb, var(--color-text-soft) 78%, var(--color-season));
  font-size: 17px;
  line-height: 1.7;
}

.footer-links a:hover {
  color: var(--color-white);
}

/* ===== LIGHTBOX ===== */
.image-lightbox {
  position: fixed;
  inset: 0;
  z-index: 9999;
  display: none;
  place-items: center;
  padding: 24px;
  background: color-mix(in srgb, var(--color-black) 94%, transparent);
}

.image-lightbox.open {
  display: grid;
}

.image-lightbox img {
  display: block;
  max-width: min(1600px,95vw);
  max-height: 90vh;
  width: auto;
  height: auto;
  object-fit: contain;
  border: 1px solid var(--color-line-strong);
  box-shadow: 0 24px 80px color-mix(in srgb, var(--color-black) 66%, transparent);
}

.image-lightbox-close {
  position: fixed;
  right: 20px;
  top: 18px;
  width: 44px;
  height: 44px;
  border: 1px solid var(--color-line-strong);
  background: var(--color-surface);
  color: var(--color-text);
  font-size: 24px;
  line-height: 1;
  cursor: pointer;
}

.image-lightbox-hint {
  position: fixed;
  left: 50%;
  bottom: 14px;
  transform: translateX(-50%);
  margin: 0;
  color: var(--color-text-muted);
  font: 12px/1.5 Arial,sans-serif;
  letter-spacing: .06em;
  white-space: nowrap;
}

/* ===== RESPONSIVE ===== */
@media (max-width: 980px) {
  .about-book-copy {
    width: 100%;
    margin-left: 0;
  }

  .gallery-grid {
    gap: 14px;
  }

  :root {
    --current-title-width: 640px;
    --current-hero-padding-top: 52px;
    --current-hero-padding-bottom: 56px;
  }

  .hero.hero-centered,
  .hero.hero-centered .hero-inner {
    min-height: auto;
  }
}

@media (max-width: 760px) {
  .header-links {
    display: none;
  }

  .section-head {
    grid-template-columns: 66px 1fr;
    gap: 15px;
  }

  .section-icon {
    width: 60px;
    height: 60px;
    margin-top: 0;
  }

  .section-icon svg {
    width: 52px;
    height: 52px;
  }

  .gallery-card--portrait {
    grid-column: span 2;
  }

  .gallery-card--wide {
    grid-column: span 3;
  }
}

@media (max-width: 620px) {
  body {
    font-size: 16px;
  }

  .wrap {
    width: min(100% - 28px,var(--max));
  }

  .back {
    font-size: 16px;
  }

  :root {
    --current-title-width: 520px;
    --current-hero-padding-top: 42px;
    --current-hero-padding-bottom: 48px;
  }

  .hero.hero-centered .hero-inner {
    width: min(100% - 24px,var(--max));
  }

  .hero-title-art {
    width: min(var(--current-title-width),94vw);
    margin-bottom: 14px;
  }

  .hero-lead {
    font-size: 14px;
    line-height: 1.95;
  }

  section:not(.hero) {
    padding: 68px 0;
  }

  .section-head {
    grid-template-columns: 54px 1fr;
    gap: 12px;
    margin-bottom: 32px;
  }

  .section-icon {
    width: 50px;
    height: 50px;
    margin-top: 0;
  }

  .section-icon svg {
    width: 44px;
    height: 44px;
  }

  h2 {
    font-size: clamp(34px,9vw,42px);
  }

  .section-lead,
  .about-book-copy,
  .purchase-box p {
    font-size: 16px;
  }

  .gallery-grid {
    grid-template-columns: 1fr;
    gap: 14px;
  }

  .gallery-card--portrait,
  .gallery-card--wide {
    grid-column: auto;
  }

  .gallery-card--portrait img {
    aspect-ratio: auto;
  }

  .purchase-grid {
    grid-template-columns: 1fr;
  }

  .purchase-box {
    min-height: auto;
    padding: 26px 22px;
  }

  .purchase-footer {
    align-items: stretch;
    flex-direction: column;
  }

  .btn {
    width: 100%;
    min-width: 0;
  }

  .edition-compare__head p {
    font-size: 14px;
  }

  .edition-compare__table th,
  .edition-compare__table td {
    padding: 14px;
  }

  .guide-link {
    font-size: 16px;
  }

  .footer-book {
    font-size: 16px;
  }

  .footer-links a {
    font-size: 15px;
  }

  .image-lightbox {
    padding: 14px;
  }

  .image-lightbox-close {
    right: 10px;
    top: 10px;
    width: 40px;
    height: 40px;
  }

  .image-lightbox-hint {
    font-size: 11px;
  }
}