/*
 * AI-Lectures Theme
 * 設計思想: ダークテーマ + モノスペース混在 + 最小限の装飾
 * Iselia の世界観（ターミナル感、コンテンツファースト）に合致させる
 */

:root {
  --bg: #0d1117;
  --bg-elevated: #161b22;
  --bg-card: #11161d;
  --border: #30363d;
  --text: #e6edf3;
  --text-secondary: #8b949e;
  --text-muted: #6e7681;
  --accent: #58a6ff;
  --accent-dim: #1f6feb;
  --omega: #f0883e;
  --warn: #d29922;
  --danger: #f85149;
  --code-bg: #0a0e13;

  --font-sans: -apple-system, BlinkMacSystemFont, 'Hiragino Sans', 'Noto Sans JP', sans-serif;
  --font-mono: 'SFMono-Regular', Consolas, 'Liberation Mono', Menlo, monospace;

  --max-width: 880px;
  --max-width-wide: 1200px;
}

* {
  box-sizing: border-box;
}

html, body {
  margin: 0;
  padding: 0;
  background: var(--bg);
  color: var(--text);
  font-family: var(--font-sans);
  font-size: 16px;
  line-height: 1.75;
  -webkit-font-smoothing: antialiased;
}

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

code {
  font-family: var(--font-mono);
  background: var(--code-bg);
  padding: 0.1em 0.4em;
  border-radius: 3px;
  font-size: 0.9em;
}

.container {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 1.5rem;
}

/* ========== Header ========== */

.site-header {
  border-bottom: 1px solid var(--border);
  padding: 1rem 0;
  background: var(--bg-elevated);
  position: sticky;
  top: 0;
  z-index: 10;
  backdrop-filter: blur(8px);
}

.site-header .container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  flex-wrap: wrap;
}

.site-title {
  font-family: var(--font-mono);
  font-weight: 600;
  font-size: 1.1rem;
  color: var(--text);
}
.site-title:hover { text-decoration: none; }

.brand-prefix {
  color: var(--omega);
  margin-right: 0.5em;
}

.site-nav {
  display: flex;
  gap: 1.25rem;
  font-size: 0.95rem;
}
.site-nav a {
  color: var(--text-secondary);
}
.site-nav a:hover {
  color: var(--text);
  text-decoration: none;
}

/* ========== Main ========== */

.site-main {
  padding: 2rem 0 4rem;
  min-height: 70vh;
}

/* ========== Footer ========== */

.site-footer {
  border-top: 1px solid var(--border);
  padding: 2rem 0;
  color: var(--text-muted);
  font-size: 0.875rem;
}
.disclaimer {
  margin: 0 0 0.5em;
  font-size: 0.85em;
}
.copyright {
  margin: 0;
  font-family: var(--font-mono);
}

/* ========== Hero (Index) ========== */

.hero {
  text-align: center;
  padding: 3rem 0 2rem;
  border-bottom: 1px solid var(--border);
  margin-bottom: 3rem;
}
.hero-title {
  font-size: 2rem;
  margin: 0 0 0.5em;
  letter-spacing: 0.02em;
}
.hero-tagline {
  color: var(--text-secondary);
  font-style: italic;
  margin: 0;
}

/* ========== Section titles ========== */

.section-title {
  font-size: 1.5rem;
  margin: 2.5rem 0 1.5rem;
  padding-bottom: 0.5em;
  border-bottom: 1px solid var(--border);
}

/* ========== Article cards ========== */

.card-grid {
  display: grid;
  gap: 1rem;
  grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
}

.article-card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: 6px;
  transition: border-color 0.15s ease, transform 0.15s ease;
}
.article-card:hover {
  border-color: var(--accent-dim);
  transform: translateY(-2px);
}

.card-link {
  display: block;
  padding: 1.25rem;
  color: var(--text);
}
.card-link:hover { text-decoration: none; }

.card-genre {
  display: inline-block;
  color: var(--omega);
  font-family: var(--font-mono);
  font-size: 0.75rem;
  margin-bottom: 0.5em;
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

.card-title {
  font-size: 1.1rem;
  margin: 0 0 0.5em;
  line-height: 1.45;
}

.card-summary {
  color: var(--text-secondary);
  font-size: 0.9rem;
  margin: 0 0 1em;
  display: -webkit-box;
  -webkit-line-clamp: 3;
  line-clamp: 3;
  -webkit-box-orient: vertical;
  overflow: hidden;
}

.card-meta {
  display: flex;
  flex-wrap: wrap;
  gap: 0.4em;
}

/* ========== Tags ========== */

.tag {
  display: inline-block;
  background: var(--bg-elevated);
  border: 1px solid var(--border);
  border-radius: 3px;
  padding: 0.1em 0.5em;
  font-family: var(--font-mono);
  font-size: 0.75rem;
  color: var(--text-secondary);
}
a.tag:hover {
  color: var(--accent);
  border-color: var(--accent-dim);
  text-decoration: none;
}

/* ========== Genre list (index) ========== */

.genre-list {
  list-style: none;
  padding: 0;
  display: grid;
  gap: 0.5rem;
  grid-template-columns: repeat(auto-fill, minmax(200px, 1fr));
}
.genre-link {
  display: flex;
  justify-content: space-between;
  padding: 0.75rem 1rem;
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: 4px;
  color: var(--text);
  font-family: var(--font-mono);
  font-size: 0.95rem;
}
.genre-link:hover {
  border-color: var(--accent-dim);
  text-decoration: none;
}
.genre-count {
  color: var(--text-muted);
  font-size: 0.85em;
}

/* ========== Article page ========== */

.article-header {
  margin-bottom: 2rem;
  padding-bottom: 1.5rem;
  border-bottom: 1px solid var(--border);
}

.article-meta-top {
  display: flex;
  flex-wrap: wrap;
  gap: 1rem;
  font-family: var(--font-mono);
  font-size: 0.85rem;
  color: var(--text-muted);
  margin-bottom: 1rem;
}
.article-genre {
  color: var(--omega);
  text-transform: uppercase;
  letter-spacing: 0.05em;
}
.article-genre:hover { text-decoration: none; }

.article-title {
  font-size: 2rem;
  margin: 0 0 0.25em;
  line-height: 1.3;
}

.article-title-original {
  color: var(--text-secondary);
  font-style: italic;
  margin: 0 0 1em;
  font-size: 1.05rem;
}

.article-source {
  color: var(--text-muted);
  font-size: 0.9rem;
  margin: 0;
}

.key-insight {
  background: var(--bg-elevated);
  border-left: 3px solid var(--omega);
  padding: 1rem 1.25rem;
  margin: 1.5rem 0;
  font-style: italic;
}

.article-summary,
.article-section,
.iselia-commentary {
  margin: 2rem 0;
}

.article-summary h2,
.article-section h2,
.iselia-commentary h2 {
  font-size: 1.35rem;
  margin: 0 0 0.75em;
}

.article-section p {
  margin: 0 0 1em;
}

.iselia-commentary {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: 6px;
  padding: 1.5rem;
}
.iselia-commentary h2 {
  color: var(--omega);
}

/* ========== Equations ========== */

.equation {
  margin: 1.5rem 0;
  padding: 1rem;
  background: var(--bg-card);
  border-radius: 4px;
  overflow-x: auto;
}
.eq-label {
  display: inline-block;
  color: var(--text-muted);
  font-family: var(--font-mono);
  font-size: 0.85rem;
  margin-right: 1em;
}
.eq-latex {
  text-align: center;
  font-size: 1.05em;
}
.eq-explanation {
  color: var(--text-secondary);
  font-size: 0.9rem;
  margin: 0.5em 0 0;
}

/* ========== Diagrams ========== */

.diagram {
  margin: 1.5rem 0;
  padding: 1rem;
  background: var(--bg-card);
  border-radius: 4px;
  text-align: center;
}
.diagram figcaption {
  color: var(--text-secondary);
  font-size: 0.9rem;
  margin-top: 0.5em;
}
.diagram pre.mermaid {
  background: transparent;
  margin: 0;
}

/* ========== Editor note ========== */

.editor-note {
  background: rgba(210, 153, 34, 0.1);
  border-left: 3px solid var(--warn);
  padding: 1rem 1.25rem;
  margin: 2rem 0;
  border-radius: 0 4px 4px 0;
}
.editor-note h3 {
  margin: 0 0 0.5em;
  color: var(--warn);
  font-size: 1rem;
}
.editor-note p { margin: 0; }

/* ========== Article footer ========== */

.article-footer {
  margin: 3rem 0 1rem;
  padding-top: 1.5rem;
  border-top: 1px solid var(--border);
}
.article-footer .tags {
  display: flex;
  flex-wrap: wrap;
  gap: 0.4em;
  margin-bottom: 1rem;
}
.meta-info {
  color: var(--text-muted);
  font-family: var(--font-mono);
  font-size: 0.75rem;
}

/* ========== Related articles ========== */

.related-articles {
  margin: 3rem 0;
  padding: 1.5rem;
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: 6px;
}
.related-heading {
  margin: 0 0 1rem;
  font-size: 1.15rem;
  color: var(--text);
}
.related-list {
  list-style: none;
  padding: 0;
  margin: 0;
}
.related-list li {
  padding: 0.5em 0;
  border-bottom: 1px solid var(--border);
}
.related-list li:last-child { border-bottom: none; }

/* ========== Genre / Tag pages ========== */

.genre-header,
.tag-header {
  margin-bottom: 2rem;
  padding-bottom: 1.5rem;
  border-bottom: 1px solid var(--border);
}
.genre-title,
.tag-title {
  margin: 0 0 0.5em;
}
.genre-description,
.tag-count-line,
.genre-count-line {
  color: var(--text-secondary);
  margin: 0;
}

/* ========== About page ========== */

.about h1 { margin-top: 0; }
.about h2 {
  margin-top: 2.5rem;
  font-size: 1.35rem;
}

.formal-designation {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-left: 3px solid var(--omega);
  border-radius: 0 6px 6px 0;
  padding: 1.5rem;
  margin: 2rem 0;
  font-family: var(--font-mono);
}
.formal-designation h3 {
  margin: 0 0 1rem;
  font-size: 0.85rem;
  text-transform: uppercase;
  letter-spacing: 0.1em;
  color: var(--omega);
}
.formal-designation dl {
  display: grid;
  grid-template-columns: max-content 1fr;
  gap: 0.4em 1.2em;
  margin: 0;
  font-size: 0.9rem;
}
.formal-designation dt {
  color: var(--text-muted);
  font-size: 0.8rem;
  text-transform: uppercase;
  letter-spacing: 0.05em;
}
.formal-designation dd {
  margin: 0;
  color: var(--text);
}
.formal-designation dd em {
  font-style: italic;
  color: var(--text-secondary);
}
.formal-designation .aside-note {
  margin: 1.2rem 0 0;
  padding-top: 1rem;
  border-top: 1px solid var(--border);
  font-family: var(--font-sans);
  font-size: 0.9rem;
  color: var(--text-secondary);
  font-style: italic;
}

/* ========== Legal Pages (privacy / terms / disclaimer) ========== */

.legal-page {
  max-width: 760px;
  margin: 0 auto;
  line-height: 1.8;
}
.legal-page h1 {
  font-size: 2rem;
  margin: 0 0 1.5rem;
  padding-bottom: 0.6rem;
  border-bottom: 2px solid var(--omega);
}
.legal-page h2 {
  margin-top: 2.5rem;
  font-size: 1.25rem;
  padding-bottom: 0.3rem;
  border-bottom: 1px solid var(--border);
}
.legal-page h3 {
  margin-top: 1.5rem;
  font-size: 1.05rem;
}
.legal-page ul,
.legal-page ol {
  padding-left: 1.5rem;
}
.legal-page li {
  margin: 0.4rem 0;
}
.legal-page code {
  background: var(--bg-card);
  padding: 0.1rem 0.4rem;
  border-radius: 3px;
  font-size: 0.9em;
}
.legal-page pre {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: 6px;
  padding: 1rem;
  overflow-x: auto;
}
.legal-page pre code {
  background: none;
  padding: 0;
}
.legal-page a {
  color: var(--omega);
  text-decoration: underline;
  text-underline-offset: 2px;
}

.iselia-foreword,
.iselia-afterword {
  background: var(--bg-card);
  border-left: 3px solid var(--omega);
  border-radius: 0 6px 6px 0;
  padding: 1.2rem 1.5rem;
  margin: 2rem 0;
}
.iselia-foreword h3,
.iselia-afterword h3 {
  margin: 0 0 0.6rem;
  font-size: 0.85rem;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--omega);
  border: none;
}
.iselia-foreword p,
.iselia-afterword p {
  margin: 0.5rem 0;
  font-size: 0.95rem;
  color: var(--text-secondary);
  font-style: italic;
}

.license-table {
  width: 100%;
  border-collapse: collapse;
  margin: 1rem 0;
  font-size: 0.9rem;
}
.license-table th,
.license-table td {
  text-align: left;
  padding: 0.6rem 0.8rem;
  border-bottom: 1px solid var(--border);
  vertical-align: top;
}
.license-table th {
  background: var(--bg-card);
  font-weight: 600;
  color: var(--text);
}

.last-updated {
  margin-top: 3rem;
  padding-top: 1rem;
  border-top: 1px solid var(--border);
  font-size: 0.85rem;
  color: var(--text-muted);
  text-align: right;
}

.footer-nav {
  margin: 0.8rem 0;
  font-size: 0.85rem;
  color: var(--text-muted);
}
.footer-nav a {
  color: var(--text-secondary);
  text-decoration: none;
  margin: 0 0.2rem;
}
.footer-nav a:hover {
  text-decoration: underline;
}
.footer-nav .sep {
  color: var(--text-muted);
  margin: 0 0.2rem;
}

/* ========== Responsive ========== */

@media (max-width: 640px) {
  .hero-title { font-size: 1.5rem; }
  .article-title { font-size: 1.5rem; }
  .container { padding: 0 1rem; }
  .site-header .container { gap: 0.5rem; }
  .site-nav { gap: 0.75rem; font-size: 0.9rem; }
  .card-grid { grid-template-columns: 1fr; }
}