/* =====================================================
   Books — site styles
   public-pages/assets/style.css

   構成:
     1. テーマトークン（CSS 変数）
     2. ベース / リセット
     3. サイトヘッダー
     4. メイン / フッター
     5. ホーム（ルート index）
     6. セクション index
     7. カード
     8. 記事ページ
     9. 参考リンク
    10. レスポンシブ
   ===================================================== */

/* ─── 1. テーマトークン ─── */

:root,
[data-theme="light"] {
  --color-bg:               #fafaf9;
  --color-surface:          #ffffff;
  --color-surface-hover:    #f5f5f4;
  --color-text:             #1c1917;
  --color-text-muted:       #57534e;
  --color-text-faint:       #a8a29e;
  --color-border:           #e7e5e4;
  --color-border-strong:    #d6d3d1;
  --color-link:             #0969da;
  --color-link-hover:       #0550ae;
  --color-tag-bg:           #f0f6fc;
  --color-tag-text:         #0969da;
  --color-category-bg:      #fef3c7;
  --color-category-text:    #92400e;
  --color-header-bg:        rgba(250, 250, 249, 0.85);

  --shadow-card:            0 1px 2px rgba(0, 0, 0, 0.04);
  --shadow-card-hover:      0 6px 20px rgba(0, 0, 0, 0.08);

  --radius-card:            12px;
  --radius-pill:            999px;

  --font-sans:              -apple-system, BlinkMacSystemFont, "Segoe UI",
                            "Hiragino Sans", "Hiragino Kaku Gothic ProN",
                            "Noto Sans JP", "Yu Gothic UI", Meiryo, sans-serif;
  --font-serif:             ui-serif, Georgia, "Times New Roman",
                            "Hiragino Mincho ProN", "Yu Mincho", serif;

  --content-width:          820px;
  --header-width:           1080px;
}

[data-theme="dark"] {
  --color-bg:               #0d1117;
  --color-surface:          #161b22;
  --color-surface-hover:    #1c2128;
  --color-text:             #e6edf3;
  --color-text-muted:       #7d8590;
  --color-text-faint:       #6e7681;
  --color-border:           #30363d;
  --color-border-strong:    #484f58;
  --color-link:             #58a6ff;
  --color-link-hover:       #79c0ff;
  --color-tag-bg:           rgba(56, 139, 253, 0.12);
  --color-tag-text:         #79c0ff;
  --color-category-bg:      rgba(187, 128, 9, 0.15);
  --color-category-text:    #d29922;
  --color-header-bg:        rgba(13, 17, 23, 0.85);

  --shadow-card:            0 1px 2px rgba(0, 0, 0, 0.3);
  --shadow-card-hover:      0 6px 20px rgba(0, 0, 0, 0.4);
}

/* ─── 2. ベース / リセット ─── */

*,
*::before,
*::after { box-sizing: border-box; }

html { color-scheme: light dark; }

body {
  margin: 0;
  background: var(--color-bg);
  color: var(--color-text);
  font-family: var(--font-sans);
  font-size: 16px;
  line-height: 1.7;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
  transition: background-color 0.15s ease, color 0.15s ease;
}

a {
  color: var(--color-link);
  text-decoration: none;
}
a:hover { text-decoration: underline; }

/* github-markdown-css は .markdown-body に白/黒の背景を付けるので、
   ページ背景に溶け込ませるために透過に上書き */
.markdown-body { background: transparent; }

/* ─── 3. サイトヘッダー ─── */

.site-header {
  position: sticky;
  top: 0;
  z-index: 50;
  background: var(--color-header-bg);
  backdrop-filter: saturate(180%) blur(12px);
  -webkit-backdrop-filter: saturate(180%) blur(12px);
  border-bottom: 1px solid var(--color-border);
}

.site-header-inner {
  max-width: var(--header-width);
  margin: 0 auto;
  padding: 0.875rem 1.25rem;
  display: flex;
  align-items: center;
  gap: 1.5rem;
}

.site-brand {
  display: inline-flex;
  align-items: baseline;
  gap: 0.4rem;
  color: var(--color-text);
  font-weight: 600;
  letter-spacing: -0.01em;
}
.site-brand:hover { text-decoration: none; }

.site-brand-mark {
  color: var(--color-link);
  font-size: 1.1em;
}

.site-brand-name {
  font-family: var(--font-serif);
  font-size: 1.25rem;
  letter-spacing: 0.02em;
}

.site-nav {
  display: flex;
  flex-wrap: wrap;
  gap: 0.25rem;
  margin-left: auto;
  margin-right: 0.5rem;
}

.site-nav-link {
  padding: 0.35rem 0.8rem;
  border-radius: var(--radius-pill);
  color: var(--color-text-muted);
  font-size: 0.875rem;
  font-weight: 500;
  transition: background-color 0.15s ease, color 0.15s ease;
}
.site-nav-link:hover {
  background: var(--color-surface-hover);
  color: var(--color-text);
  text-decoration: none;
}
.site-nav-link.is-current {
  background: var(--color-surface);
  color: var(--color-text);
  box-shadow: inset 0 0 0 1px var(--color-border);
}

.theme-toggle {
  width: 36px;
  height: 36px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-pill);
  background: var(--color-surface);
  color: var(--color-text);
  cursor: pointer;
  transition: background-color 0.15s ease, transform 0.1s ease;
}
.theme-toggle:hover { background: var(--color-surface-hover); }
.theme-toggle:active { transform: scale(0.94); }

.theme-toggle-icon {
  font-size: 1rem;
  line-height: 1;
}
[data-theme="light"] .theme-toggle-icon[data-theme-show="dark"],
[data-theme="dark"]  .theme-toggle-icon[data-theme-show="light"] {
  display: none;
}

/* ─── 4. メイン / フッター ─── */

.site-main {
  max-width: var(--content-width);
  margin: 0 auto;
  padding: 2.5rem 1.25rem 4rem;
}

.site-footer {
  border-top: 1px solid var(--color-border);
  margin-top: 4rem;
}
.site-footer-inner {
  max-width: var(--header-width);
  margin: 0 auto;
  padding: 1.5rem 1.25rem;
  color: var(--color-text-faint);
  font-size: 0.875rem;
}
.site-footer-inner p { margin: 0; }

/* ─── 5. ホーム（ルート index）─── */

.home-header {
  margin-bottom: 3rem;
}
.home-title {
  font-family: var(--font-serif);
  font-size: 3rem;
  font-weight: 600;
  letter-spacing: -0.02em;
  line-height: 1.1;
  margin: 0 0 0.5rem;
}
.home-lead {
  color: var(--color-text-muted);
  font-size: 1.1rem;
  margin: 0;
}

.home-section { margin-bottom: 3rem; }

.home-section-header {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: 1rem;
  padding-bottom: 0.75rem;
  margin-bottom: 1rem;
  border-bottom: 1px solid var(--color-border);
}
.home-section-header h2 {
  margin: 0;
  font-size: 1.5rem;
  font-weight: 600;
  letter-spacing: -0.01em;
}
.home-section-header h2 a { color: inherit; }
.home-section-header h2 a:hover {
  color: var(--color-link);
  text-decoration: none;
}
.home-section-more {
  font-size: 0.875rem;
  color: var(--color-text-muted);
  white-space: nowrap;
}
.home-section-more:hover { color: var(--color-link); }

/* ─── 6. セクション index ─── */

.section-index-header {
  margin-bottom: 2rem;
  padding-bottom: 1rem;
  border-bottom: 1px solid var(--color-border);
}
.section-index-header h1 {
  font-family: var(--font-serif);
  font-size: 2.25rem;
  font-weight: 600;
  letter-spacing: -0.02em;
  margin: 0 0 0.25rem;
}
.section-index-count {
  margin: 0;
  color: var(--color-text-faint);
  font-size: 0.875rem;
}

/* ─── 7. カード ─── */

.card-list {
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
}

.card {
  display: block;
  padding: 1.25rem 1.5rem;
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-card);
  color: inherit;
  box-shadow: var(--shadow-card);
  transition: border-color 0.15s ease, box-shadow 0.2s ease, transform 0.15s ease;
}
.card:hover {
  border-color: var(--color-border-strong);
  box-shadow: var(--shadow-card-hover);
  transform: translateY(-1px);
  text-decoration: none;
}

.card-category {
  display: inline-block;
  font-size: 0.7rem;
  font-weight: 600;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  color: var(--color-category-text);
  background: var(--color-category-bg);
  padding: 0.2rem 0.55rem;
  border-radius: 4px;
  margin-bottom: 0.5rem;
}

.card-title {
  margin: 0 0 0.5rem;
  font-size: 1.15rem;
  font-weight: 600;
  letter-spacing: -0.005em;
  line-height: 1.4;
}

.card-excerpt {
  margin: 0 0 0.875rem;
  color: var(--color-text-muted);
  font-size: 0.925rem;
  line-height: 1.6;
  display: -webkit-box;
  -webkit-line-clamp: 2;
  -webkit-box-orient: vertical;
  overflow: hidden;
}

.card-footer {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 0.5rem;
  font-size: 0.8rem;
  color: var(--color-text-faint);
}
.card-meta {
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
}
.card-sep {
  color: var(--color-text-faint);
  opacity: 0.5;
}

.card-tags {
  list-style: none;
  padding: 0;
  margin: 0;
  display: flex;
  flex-wrap: wrap;
  gap: 0.3rem;
}
.card-tags li {
  font-size: 0.72rem;
  color: var(--color-tag-text);
  background: var(--color-tag-bg);
  padding: 0.15rem 0.5rem;
  border-radius: 4px;
}

/* ─── 8. 記事ページ ─── */

.article-header {
  margin-bottom: 2rem;
  padding-bottom: 1.5rem;
  border-bottom: 1px solid var(--color-border);
}
/* github-markdown-css の h1 下線を上書き */
.article-header h1 {
  border-bottom: none;
  padding-bottom: 0;
  margin-bottom: 0.75rem;
}
.article-meta {
  display: flex;
  align-items: center;
  flex-wrap: wrap;
  gap: 0.75rem;
  margin: 0 0 1rem;
  font-size: 0.9rem;
  color: var(--color-text-muted);
}
.meta-category {
  display: inline-block;
  padding: 0.15rem 0.6rem;
  border: 1px solid var(--color-border-strong);
  border-radius: var(--radius-pill);
  font-size: 0.75rem;
}

/* 記事ヘッダー内の tags */
ul.tags {
  list-style: none;
  padding: 0;
  margin: 0;
  display: flex;
  flex-wrap: wrap;
  gap: 0.4rem;
}
ul.tags li {
  font-size: 0.78rem;
  color: var(--color-tag-text);
  background: var(--color-tag-bg);
  padding: 0.2rem 0.6rem;
  border-radius: 4px;
}

/* ─── 9. 参考リンク ─── */

.sources {
  margin-top: 3rem;
  padding-top: 1.5rem;
  border-top: 1px solid var(--color-border);
}
.sources h2 {
  font-size: 0.875rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--color-text-muted);
  border-bottom: none;
  padding-bottom: 0;
  margin: 0 0 0.75rem;
}
.sources ul {
  list-style: none;
  padding: 0;
  margin: 0;
  display: flex;
  flex-direction: column;
  gap: 0.3rem;
}
.sources a {
  display: inline-flex;
  align-items: baseline;
  gap: 0.4rem;
  padding: 0.25rem 0;
  font-size: 0.9rem;
}
.sources .src-host {
  color: var(--color-text);
  font-weight: 500;
}
.sources .src-path {
  color: var(--color-text-faint);
  font-size: 0.85em;
}

/* ─── 10. レスポンシブ ─── */

@media (max-width: 640px) {
  .site-header-inner {
    padding: 0.75rem 1rem;
    gap: 0.75rem;
  }
  .site-brand-name { font-size: 1.1rem; }
  .site-nav {
    margin-left: 0;
    flex: 1;
    justify-content: flex-end;
    overflow-x: auto;
    -webkit-overflow-scrolling: touch;
    scrollbar-width: none;
  }
  .site-nav::-webkit-scrollbar { display: none; }
  .site-nav-link { white-space: nowrap; }

  .home-title { font-size: 2.25rem; }
  .section-index-header h1 { font-size: 1.75rem; }
  .card { padding: 1rem 1.1rem; }
  .home-section-header {
    flex-direction: column;
    align-items: flex-start;
    gap: 0.25rem;
  }
}