/* ============================================
   AI知識の泉 — Academic Journal Design
   ============================================ */

@import url('https://fonts.googleapis.com/css2?family=Noto+Serif+JP:wght@400;500;600;700;900&family=Inter:wght@300;400;500;600;700&display=swap');

:root {
  --bg-primary: #faf8f5;
  --bg-secondary: #f0ece4;
  --bg-card: #ffffff;
  --bg-code: #f5f0e8;
  --bg-callout: #f8f5ef;
  --bg-header: rgba(250, 248, 245, 0.95);

  --color-primary: #1a1a2e;
  --color-accent: #b8860b;
  --color-accent-light: #d4a337;
  --color-accent-dark: #8b6508;
  --color-accent-bg: rgba(184, 134, 11, 0.08);
  --color-text: #2c2c2c;
  --color-text-secondary: #5a6c7d;
  --color-text-muted: #8a95a3;
  --color-border: #e0dbd3;
  --color-border-light: #ebe7e0;
  --color-link: #1a5276;
  --color-link-hover: #b8860b;

  --font-serif: 'Noto Serif JP', 'Georgia', serif;
  --font-sans: 'Inter', 'Noto Serif JP', sans-serif;

  --shadow-sm: 0 1px 3px rgba(0,0,0,0.06);
  --shadow-md: 0 4px 12px rgba(0,0,0,0.08);
  --shadow-lg: 0 8px 30px rgba(0,0,0,0.1);
  --shadow-card: 0 2px 8px rgba(0,0,0,0.05), 0 1px 2px rgba(0,0,0,0.04);

  --radius-sm: 4px;
  --radius-md: 8px;
  --radius-lg: 12px;

  --transition: 0.25s ease;
  --max-width: 1200px;
  --content-width: 820px;
}

/* ---- Dark Mode ---- */
@media (prefers-color-scheme: dark) {
  :root {
    --bg-primary: #1a1a2e;
    --bg-secondary: #16213e;
    --bg-card: #1e2a45;
    --bg-code: #243047;
    --bg-callout: #1e2a45;
    --bg-header: rgba(26, 26, 46, 0.95);
    --color-primary: #faf8f5;
    --color-accent: #d4a337;
    --color-accent-light: #e8be5a;
    --color-accent-bg: rgba(212, 163, 55, 0.12);
    --color-text: #e0dbd3;
    --color-text-secondary: #a8b4c2;
    --color-text-muted: #7a8696;
    --color-border: #2a3a52;
    --color-border-light: #243047;
    --color-link: #7db8d4;
    --color-link-hover: #e8be5a;
    --shadow-sm: 0 1px 3px rgba(0,0,0,0.2);
    --shadow-md: 0 4px 12px rgba(0,0,0,0.3);
    --shadow-lg: 0 8px 30px rgba(0,0,0,0.4);
    --shadow-card: 0 2px 8px rgba(0,0,0,0.2);
  }
}

/* ---- Reset ---- */
*, *::before, *::after { margin: 0; padding: 0; box-sizing: border-box; }
html { scroll-behavior: smooth; font-size: 16px; }

body {
  font-family: var(--font-serif);
  background: var(--bg-primary);
  color: var(--color-text);
  line-height: 1.9;
  overflow-x: hidden;
  min-height: 100vh;
}

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

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

/* ---- Reading Progress Bar ---- */
.reading-progress {
  position: fixed; top: 0; left: 0;
  width: 0%; height: 3px;
  background: linear-gradient(90deg, var(--color-accent), var(--color-accent-light));
  z-index: 1000;
  transition: width 0.1s linear;
}

/* ---- Container ---- */
.container { max-width: var(--max-width); margin: 0 auto; padding: 0 2rem; }
.content-container { max-width: var(--content-width); margin: 0 auto; }

/* ============ HEADER ============ */
.header {
  position: sticky; top: 0; z-index: 100;
  background: var(--bg-header);
  backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--color-border-light);
  padding: 0;
}
.header-inner {
  display: flex; align-items: center; justify-content: space-between;
  height: 72px;
}
.logo { display: flex; flex-direction: column; text-decoration: none; }
.logo-main {
  font-family: var(--font-serif);
  font-size: 1.35rem; font-weight: 700;
  color: var(--color-primary);
  letter-spacing: 0.03em;
}
.logo-main span { color: var(--color-accent); }
.logo-sub {
  font-family: var(--font-sans);
  font-size: 0.7rem; color: var(--color-text-muted);
  letter-spacing: 0.08em; text-transform: uppercase;
}

.nav { display: flex; gap: 0.25rem; align-items: center; }
.nav-link {
  font-family: var(--font-sans);
  font-size: 0.88rem; font-weight: 500;
  color: var(--color-text-secondary);
  padding: 0.5rem 0.85rem; border-radius: var(--radius-sm);
  transition: all var(--transition);
}
.nav-link:hover, .nav-link.active {
  color: var(--color-accent);
  background: var(--color-accent-bg);
}

.hamburger {
  display: none; flex-direction: column; gap: 5px;
  cursor: pointer; padding: 8px; z-index: 200;
}
.hamburger span {
  width: 24px; height: 2px;
  background: var(--color-text); border-radius: 2px;
  transition: all var(--transition);
}
.hamburger.active span:nth-child(1) { transform: rotate(45deg) translate(5px, 5px); }
.hamburger.active span:nth-child(2) { opacity: 0; }
.hamburger.active span:nth-child(3) { transform: rotate(-45deg) translate(5px, -5px); }

/* ============ HERO ============ */
.hero {
  background: linear-gradient(135deg, var(--color-primary) 0%, #16213e 50%, #0f3460 100%);
  color: #fff;
  padding: 5rem 0 4rem;
  position: relative;
  overflow: hidden;
}
.hero::before {
  content: '';
  position: absolute; top: 0; left: 0; width: 100%; height: 100%;
  background: url("data:image/svg+xml,%3Csvg width='60' height='60' viewBox='0 0 60 60' xmlns='http://www.w3.org/2000/svg'%3E%3Cg fill='none' fill-rule='evenodd'%3E%3Cg fill='%23ffffff' fill-opacity='0.03'%3E%3Cpath d='M36 34v-4h-2v4h-4v2h4v4h2v-4h4v-2h-4zm0-30V0h-2v4h-4v2h4v4h2V6h4V4h-4zM6 34v-4H4v4H0v2h4v4h2v-4h4v-2H6zM6 4V0H4v4H0v2h4v4h2V6h4V4H6z'/%3E%3C/g%3E%3C/g%3E%3C/svg%3E");
  opacity: 0.5;
}
.hero-content {
  position: relative; z-index: 1;
  text-align: center;
  max-width: 800px; margin: 0 auto;
}
.hero-badge {
  display: inline-block;
  font-family: var(--font-sans);
  font-size: 0.75rem; font-weight: 600;
  letter-spacing: 0.15em; text-transform: uppercase;
  color: var(--color-accent-light);
  border: 1px solid rgba(212, 163, 55, 0.4);
  padding: 0.35rem 1.2rem;
  border-radius: 20px;
  margin-bottom: 1.5rem;
}
.hero h1 {
  font-family: var(--font-serif);
  font-size: 2.8rem; font-weight: 900;
  line-height: 1.3;
  margin-bottom: 1rem;
}
.hero h1 .accent { color: var(--color-accent-light); }
.hero-tagline {
  font-size: 1.15rem; font-weight: 400;
  color: rgba(255,255,255,0.8);
  line-height: 1.7;
  margin-bottom: 2rem;
}
.hero-stats {
  display: flex; justify-content: center; gap: 3rem;
  margin-top: 2.5rem;
}
.hero-stat { text-align: center; }
.hero-stat-number {
  display: block;
  font-family: var(--font-sans);
  font-size: 2rem; font-weight: 700;
  color: var(--color-accent-light);
}
.hero-stat-label {
  font-family: var(--font-sans);
  font-size: 0.8rem;
  color: rgba(255,255,255,0.6);
  letter-spacing: 0.05em;
}

/* ============ SECTIONS ============ */
.section {
  padding: 4rem 0;
}
.section-header {
  text-align: center;
  margin-bottom: 3rem;
}
.section-title {
  font-family: var(--font-serif);
  font-size: 1.8rem; font-weight: 700;
  color: var(--color-primary);
  margin-bottom: 0.5rem;
}
.section-title::after {
  content: '';
  display: block;
  width: 50px; height: 3px;
  background: var(--color-accent);
  margin: 0.75rem auto 0;
  border-radius: 2px;
}
.section-desc {
  font-size: 1rem;
  color: var(--color-text-secondary);
  max-width: 600px; margin: 1rem auto 0;
}

/* ============ CATEGORY CARDS ============ */
.category-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 1.5rem;
}
.category-card {
  background: var(--bg-card);
  border: 1px solid var(--color-border-light);
  border-radius: var(--radius-lg);
  padding: 2rem;
  transition: all var(--transition);
  text-decoration: none;
  color: inherit;
  display: block;
  position: relative;
  overflow: hidden;
}
.category-card::before {
  content: '';
  position: absolute; top: 0; left: 0;
  width: 100%; height: 4px;
  background: var(--color-accent);
  transform: scaleX(0);
  transform-origin: left;
  transition: transform 0.4s ease;
}
.category-card:hover {
  box-shadow: var(--shadow-lg);
  border-color: var(--color-accent);
  transform: translateY(-3px);
}
.category-card:hover::before { transform: scaleX(1); }

.category-icon {
  width: 52px; height: 52px;
  background: var(--color-accent-bg);
  border-radius: var(--radius-md);
  display: flex; align-items: center; justify-content: center;
  margin-bottom: 1.2rem;
  color: var(--color-accent);
}
.category-icon svg { width: 26px; height: 26px; }
.category-card h3 {
  font-family: var(--font-serif);
  font-size: 1.15rem; font-weight: 700;
  color: var(--color-primary);
  margin-bottom: 0.5rem;
}
.category-card p {
  font-size: 0.92rem; line-height: 1.7;
  color: var(--color-text-secondary);
  margin-bottom: 1rem;
}
.category-meta {
  font-family: var(--font-sans);
  font-size: 0.78rem;
  color: var(--color-text-muted);
  display: flex; align-items: center; gap: 0.5rem;
}
.category-count {
  background: var(--color-accent-bg);
  color: var(--color-accent);
  padding: 0.2rem 0.6rem;
  border-radius: 10px;
  font-weight: 600;
}

/* ============ ARTICLE LIST (Category Pages) ============ */
.article-list { display: flex; flex-direction: column; gap: 1rem; }
.article-item {
  background: var(--bg-card);
  border: 1px solid var(--color-border-light);
  border-radius: var(--radius-md);
  padding: 1.5rem 2rem;
  display: flex; justify-content: space-between; align-items: center;
  transition: all var(--transition);
  text-decoration: none; color: inherit;
}
.article-item:hover {
  border-color: var(--color-accent);
  box-shadow: var(--shadow-md);
  transform: translateX(4px);
}
.article-item-number {
  font-family: var(--font-sans);
  font-size: 0.75rem; font-weight: 700;
  color: var(--color-accent);
  letter-spacing: 0.05em;
  margin-bottom: 0.25rem;
}
.article-item h3 {
  font-family: var(--font-serif);
  font-size: 1.05rem; font-weight: 600;
  color: var(--color-primary);
  margin-bottom: 0.3rem;
}
.article-item p {
  font-size: 0.88rem; color: var(--color-text-secondary);
  line-height: 1.6;
}
.article-item-meta {
  font-family: var(--font-sans);
  font-size: 0.78rem;
  color: var(--color-text-muted);
  white-space: nowrap;
  margin-left: 2rem;
}

/* ============ ARTICLE PAGE LAYOUT ============ */
.article-layout {
  display: grid;
  grid-template-columns: 1fr 260px;
  gap: 3rem;
  max-width: 1120px;
  margin: 0 auto;
  padding: 2.5rem 2rem;
}
.article-main { max-width: var(--content-width); }

/* Breadcrumb */
.breadcrumb {
  font-family: var(--font-sans);
  font-size: 0.82rem;
  color: var(--color-text-muted);
  margin-bottom: 2rem;
  display: flex; flex-wrap: wrap; gap: 0.3rem;
}
.breadcrumb a { color: var(--color-text-secondary); }
.breadcrumb a:hover { color: var(--color-accent); }
.breadcrumb span { color: var(--color-border); }

/* Article Header */
.article-header { margin-bottom: 2.5rem; }
.article-category-badge {
  display: inline-block;
  font-family: var(--font-sans);
  font-size: 0.72rem; font-weight: 600;
  letter-spacing: 0.08em; text-transform: uppercase;
  color: var(--color-accent);
  background: var(--color-accent-bg);
  padding: 0.3rem 0.8rem;
  border-radius: 4px;
  margin-bottom: 1rem;
}
.article-title {
  font-family: var(--font-serif);
  font-size: 2rem; font-weight: 900;
  color: var(--color-primary);
  line-height: 1.4;
  margin-bottom: 1rem;
}
.article-meta {
  font-family: var(--font-sans);
  font-size: 0.85rem;
  color: var(--color-text-muted);
  display: flex; gap: 1.5rem; flex-wrap: wrap;
}
.article-meta-item { display: flex; align-items: center; gap: 0.35rem; }
.article-meta-item svg { width: 15px; height: 15px; opacity: 0.6; }

/* Article Body */
.article-body { font-size: 1.05rem; line-height: 1.95; }
.article-body h2 {
  font-family: var(--font-serif);
  font-size: 1.5rem; font-weight: 700;
  color: var(--color-primary);
  margin: 3rem 0 1.2rem;
  padding-bottom: 0.5rem;
  border-bottom: 2px solid var(--color-accent);
}
.article-body h3 {
  font-family: var(--font-serif);
  font-size: 1.2rem; font-weight: 600;
  color: var(--color-primary);
  margin: 2rem 0 0.8rem;
}
.article-body h4 {
  font-family: var(--font-serif);
  font-size: 1.05rem; font-weight: 600;
  color: var(--color-text-secondary);
  margin: 1.5rem 0 0.6rem;
}
.article-body p { margin-bottom: 1.2rem; }
.article-body ul, .article-body ol {
  margin: 1rem 0 1.5rem 1.5rem;
}
.article-body li { margin-bottom: 0.4rem; }
.article-body blockquote {
  border-left: 4px solid var(--color-accent);
  padding: 1rem 1.5rem;
  margin: 1.5rem 0;
  background: var(--bg-callout);
  border-radius: 0 var(--radius-sm) var(--radius-sm) 0;
  font-style: italic;
  color: var(--color-text-secondary);
}
.article-body code {
  font-family: 'Fira Code', monospace;
  font-size: 0.9em;
  background: var(--bg-code);
  padding: 0.15em 0.4em;
  border-radius: 3px;
}
.article-body pre {
  background: var(--color-primary);
  color: #e0dbd3;
  padding: 1.5rem;
  border-radius: var(--radius-md);
  overflow-x: auto;
  margin: 1.5rem 0;
  font-size: 0.9rem;
  line-height: 1.6;
}
.article-body pre code {
  background: none; padding: 0; color: inherit;
}

/* Article tables */
.article-body table {
  width: 100%;
  border-collapse: collapse;
  margin: 1.5rem 0;
  font-size: 0.95rem;
}
.article-body th {
  background: var(--color-primary);
  color: #fff;
  font-family: var(--font-sans);
  font-weight: 600;
  padding: 0.8rem 1rem;
  text-align: left;
}
.article-body td {
  padding: 0.7rem 1rem;
  border-bottom: 1px solid var(--color-border-light);
}
.article-body tr:hover td {
  background: var(--color-accent-bg);
}

/* ---- TOC (Table of Contents Sidebar) ---- */
.toc {
  position: sticky; top: 90px;
  font-family: var(--font-sans);
}
.toc-title {
  font-size: 0.75rem; font-weight: 700;
  color: var(--color-text-muted);
  letter-spacing: 0.1em; text-transform: uppercase;
  margin-bottom: 1rem;
}
.toc-list { list-style: none; }
.toc-list li { margin-bottom: 0.2rem; }
.toc-list a {
  font-size: 0.82rem; line-height: 1.5;
  color: var(--color-text-muted);
  display: block;
  padding: 0.3rem 0 0.3rem 1rem;
  border-left: 2px solid var(--color-border-light);
  transition: all var(--transition);
}
.toc-list a:hover, .toc-list a.active {
  color: var(--color-accent);
  border-left-color: var(--color-accent);
}
.toc-list a.active { font-weight: 600; }

/* ============ CALLOUT BOXES ============ */
.info-box, .warning-box, .research-note {
  padding: 1.2rem 1.5rem;
  border-radius: var(--radius-md);
  margin: 1.5rem 0;
  font-size: 0.95rem;
  line-height: 1.7;
}
.info-box {
  background: #eef5fc;
  border-left: 4px solid #3a86c9;
}
.warning-box {
  background: #fef7ec;
  border-left: 4px solid #e6a817;
}
.research-note {
  background: var(--bg-callout);
  border-left: 4px solid var(--color-accent);
}
.callout-title {
  font-family: var(--font-sans);
  font-weight: 700;
  font-size: 0.85rem;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  margin-bottom: 0.4rem;
}
.info-box .callout-title { color: #3a86c9; }
.warning-box .callout-title { color: #c8920d; }
.research-note .callout-title { color: var(--color-accent); }

@media (prefers-color-scheme: dark) {
  .info-box { background: #1a2a3a; border-left-color: #5a9fd4; }
  .warning-box { background: #2a2518; border-left-color: #d4a337; }
  .research-note { background: var(--bg-callout); }
  .info-box .callout-title { color: #5a9fd4; }
}

/* ============ SVG CHART / INFOGRAPHIC ============ */
.chart-container {
  background: var(--bg-card);
  border: 1px solid var(--color-border-light);
  border-radius: var(--radius-lg);
  padding: 2rem;
  margin: 2rem 0;
  text-align: center;
}
.chart-container svg { max-width: 100%; height: auto; }
.chart-caption {
  font-family: var(--font-sans);
  font-size: 0.82rem;
  color: var(--color-text-muted);
  margin-top: 1rem;
  font-style: italic;
}

.infographic {
  background: linear-gradient(135deg, var(--bg-card) 0%, var(--bg-secondary) 100%);
  border: 1px solid var(--color-border-light);
  border-radius: var(--radius-lg);
  padding: 2.5rem;
  margin: 2.5rem 0;
}

/* ============ REFERENCE LIST ============ */
.reference-list {
  background: var(--bg-callout);
  border-radius: var(--radius-md);
  padding: 1.5rem 2rem;
  margin: 3rem 0 1rem;
}
.reference-list h3 {
  font-family: var(--font-sans);
  font-size: 0.85rem; font-weight: 700;
  color: var(--color-text-muted);
  text-transform: uppercase;
  letter-spacing: 0.08em;
  margin-bottom: 1rem;
  padding-bottom: 0.5rem;
  border-bottom: 1px solid var(--color-border);
}
.reference-list ol {
  list-style: decimal;
  margin-left: 1.2rem;
  font-size: 0.88rem; line-height: 1.8;
  color: var(--color-text-secondary);
}
.reference-list li { margin-bottom: 0.3rem; }

/* ============ READING TIME / AUTHOR ============ */
.reading-time {
  font-family: var(--font-sans);
  font-size: 0.82rem;
  color: var(--color-text-muted);
}

.author-info {
  display: flex; align-items: center; gap: 1rem;
  padding: 1.5rem;
  background: var(--bg-callout);
  border-radius: var(--radius-md);
  margin: 2rem 0;
}
.author-avatar {
  width: 48px; height: 48px;
  border-radius: 50%;
  background: var(--color-accent-bg);
  display: flex; align-items: center; justify-content: center;
  color: var(--color-accent);
  font-family: var(--font-sans);
  font-weight: 700;
}
.author-name {
  font-family: var(--font-sans);
  font-weight: 600; font-size: 0.95rem;
  color: var(--color-primary);
}
.author-role {
  font-size: 0.82rem;
  color: var(--color-text-muted);
}

/* ============ ABOUT SECTION ============ */
.about-section {
  background: var(--bg-secondary);
  border-radius: var(--radius-lg);
  padding: 3rem;
  margin: 2rem 0;
}
.about-section h2 {
  font-family: var(--font-serif);
  font-size: 1.5rem;
  margin-bottom: 1rem;
}
.about-section p {
  color: var(--color-text-secondary);
  line-height: 1.9;
}

/* ============ LATEST ARTICLES ============ */
.latest-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 1.5rem;
}
.latest-card {
  background: var(--bg-card);
  border: 1px solid var(--color-border-light);
  border-radius: var(--radius-md);
  padding: 1.5rem;
  transition: all var(--transition);
  text-decoration: none; color: inherit;
  display: block;
}
.latest-card:hover {
  box-shadow: var(--shadow-md);
  transform: translateY(-2px);
}
.latest-card-category {
  font-family: var(--font-sans);
  font-size: 0.7rem; font-weight: 600;
  color: var(--color-accent);
  letter-spacing: 0.06em;
  text-transform: uppercase;
  margin-bottom: 0.5rem;
}
.latest-card h3 {
  font-family: var(--font-serif);
  font-size: 1rem; font-weight: 600;
  color: var(--color-primary);
  line-height: 1.5;
  margin-bottom: 0.5rem;
}
.latest-card p {
  font-size: 0.85rem;
  color: var(--color-text-secondary);
  line-height: 1.6;
}

/* ============ FOOTER ============ */
.footer {
  background: var(--color-primary);
  color: rgba(255,255,255,0.7);
  padding: 3rem 0 2rem;
  margin-top: 4rem;
}
.footer-inner {
  display: grid;
  grid-template-columns: 2fr 1fr 1fr 1fr;
  gap: 2rem;
}
.footer-brand .logo-main { color: #fff; font-size: 1.2rem; }
.footer-brand .logo-main span { color: var(--color-accent-light); }
.footer-brand p {
  font-size: 0.88rem; line-height: 1.7;
  margin-top: 0.8rem; color: rgba(255,255,255,0.5);
}
.footer h4 {
  font-family: var(--font-sans);
  font-size: 0.78rem; font-weight: 700;
  letter-spacing: 0.1em; text-transform: uppercase;
  color: var(--color-accent-light);
  margin-bottom: 1rem;
}
.footer ul { list-style: none; }
.footer li { margin-bottom: 0.4rem; }
.footer a {
  color: rgba(255,255,255,0.6);
  font-size: 0.88rem;
  transition: color var(--transition);
}
.footer a:hover { color: var(--color-accent-light); }
.footer-bottom {
  margin-top: 2rem;
  padding-top: 1.5rem;
  border-top: 1px solid rgba(255,255,255,0.1);
  text-align: center;
  font-family: var(--font-sans);
  font-size: 0.78rem;
  color: rgba(255,255,255,0.4);
}

/* ============ BACK TO TOP ============ */
.back-to-top {
  position: fixed; bottom: 2rem; right: 2rem;
  width: 44px; height: 44px;
  background: var(--color-accent);
  color: #fff;
  border: none; border-radius: 50%;
  cursor: pointer;
  display: flex; align-items: center; justify-content: center;
  opacity: 0; visibility: hidden;
  transition: all var(--transition);
  box-shadow: var(--shadow-md);
  z-index: 50;
}
.back-to-top.visible { opacity: 1; visibility: visible; }
.back-to-top:hover { background: var(--color-accent-dark); transform: translateY(-2px); }
.back-to-top svg { width: 20px; height: 20px; }

/* ============ MOBILE TOC ============ */
.toc-mobile-toggle {
  display: none;
  width: 100%;
  background: var(--bg-card);
  border: 1px solid var(--color-border-light);
  border-radius: var(--radius-md);
  padding: 0.8rem 1.2rem;
  font-family: var(--font-sans);
  font-size: 0.88rem;
  font-weight: 600;
  color: var(--color-text);
  cursor: pointer;
  margin-bottom: 1.5rem;
  text-align: left;
}

/* ============ RESPONSIVE ============ */
@media (max-width: 1024px) {
  .article-layout {
    grid-template-columns: 1fr;
  }
  .toc { display: none; }
  .toc-mobile-toggle { display: block; }
  .toc.mobile-open {
    display: block;
    position: static;
    margin-bottom: 1.5rem;
    padding: 1rem;
    background: var(--bg-card);
    border: 1px solid var(--color-border-light);
    border-radius: var(--radius-md);
  }
}
@media (max-width: 768px) {
  .hero { padding: 3rem 0 2.5rem; }
  .hero h1 { font-size: 1.8rem; }
  .hero-stats { gap: 1.5rem; }
  .hero-stat-number { font-size: 1.5rem; }
  .category-grid { grid-template-columns: 1fr; }
  .latest-grid { grid-template-columns: 1fr; }
  .footer-inner { grid-template-columns: 1fr 1fr; }
  .container { padding: 0 1rem; }
  .nav {
    display: none;
    position: fixed; top: 72px; left: 0;
    width: 100%; background: var(--bg-header);
    flex-direction: column;
    padding: 1rem;
    border-bottom: 1px solid var(--color-border-light);
    box-shadow: var(--shadow-lg);
  }
  .nav.open { display: flex; }
  .hamburger { display: flex; }
  .section { padding: 2.5rem 0; }
  .article-item { flex-direction: column; align-items: flex-start; }
  .article-item-meta { margin-left: 0; margin-top: 0.5rem; }
  .article-title { font-size: 1.5rem; }
}
@media (max-width: 480px) {
  .hero h1 { font-size: 1.5rem; }
  .hero-stats { flex-direction: column; gap: 1rem; }
  .footer-inner { grid-template-columns: 1fr; }
  .article-layout { padding: 1.5rem 1rem; }
}

/* ============ PRINT ============ */
@media print {
  .header, .footer, .toc, .back-to-top, .reading-progress, .hamburger { display: none !important; }
  body { background: #fff; color: #000; font-size: 11pt; }
  .article-layout { display: block; max-width: 100%; }
  .article-body h2 { border-bottom: 1pt solid #000; }
  a { color: #000; text-decoration: underline; }
  a[href]::after { content: " (" attr(href) ")"; font-size: 0.8em; }
  .reference-list { break-inside: avoid; }
}