/* Claude Tutorials JP - Official Style */
:root {
  --color-bg: #FAFAF8;
  --color-surface: #FFFFFF;
  --color-text: #1A1A1A;
  --color-text-secondary: #6B6B6B;
  --color-text-tertiary: #999999;
  --color-border: #E8E5E0;
  --color-accent: #D97706;
  --color-accent-bg: #FEF3C7;
  --color-link: #1A1A1A;
  --color-link-hover: #D97706;
  --color-tag-bg: #F3F2EF;
  --color-tag-text: #6B6B6B;
  --font-sans: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', 'Hiragino Kaku Gothic ProN', 'Noto Sans JP', sans-serif;
  --font-mono: 'JetBrains Mono', 'Fira Code', monospace;
  --max-width: 1200px;
  --max-width-article: 760px;
  --radius: 8px;
  --shadow-sm: 0 1px 2px rgba(0,0,0,0.04);
  --shadow-md: 0 4px 12px rgba(0,0,0,0.06);
  --transition: 0.2s ease;
}

*, *::before, *::after {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

html {
  font-size: 16px;
  scroll-behavior: smooth;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

body {
  font-family: var(--font-sans);
  color: var(--color-text);
  background: var(--color-bg);
  line-height: 1.7;
}

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;
}

/* Header */
.site-header {
  background: var(--color-surface);
  border-bottom: 1px solid var(--color-border);
  position: sticky;
  top: 0;
  z-index: 100;
}

.header-inner {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 24px;
  height: 60px;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.site-logo {
  display: flex;
  align-items: center;
  gap: 10px;
  font-size: 1.1rem;
  font-weight: 600;
  color: var(--color-text);
  text-decoration: none;
}

.site-logo:hover {
  color: var(--color-text);
}

.logo-icon {
  width: 28px;
  height: 28px;
  background: var(--color-accent);
  border-radius: 6px;
  display: flex;
  align-items: center;
  justify-content: center;
  color: white;
  font-size: 16px;
  font-weight: 700;
}

.header-nav {
  display: flex;
  align-items: center;
  gap: 24px;
}

.header-nav a {
  font-size: 0.875rem;
  font-weight: 500;
  color: var(--color-text-secondary);
}

.header-nav a:hover {
  color: var(--color-text);
}

.badge-unofficial {
  font-size: 0.7rem;
  background: var(--color-accent-bg);
  color: var(--color-accent);
  padding: 2px 8px;
  border-radius: 12px;
  font-weight: 600;
  white-space: nowrap;
}

/* Hero */
.hero {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 64px 24px 48px;
}

.hero h1 {
  font-size: 2.5rem;
  font-weight: 700;
  line-height: 1.2;
  letter-spacing: -0.02em;
  margin-bottom: 16px;
}

.hero p {
  font-size: 1.125rem;
  color: var(--color-text-secondary);
  max-width: 640px;
  line-height: 1.6;
}

/* Filter */
.filter-bar {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 24px 32px;
  display: flex;
  gap: 12px;
  flex-wrap: wrap;
}

.filter-btn {
  padding: 6px 16px;
  border: 1px solid var(--color-border);
  border-radius: 20px;
  background: var(--color-surface);
  color: var(--color-text-secondary);
  font-size: 0.85rem;
  font-weight: 500;
  cursor: pointer;
  transition: all var(--transition);
  font-family: var(--font-sans);
}

.filter-btn:hover,
.filter-btn.active {
  background: var(--color-text);
  color: var(--color-surface);
  border-color: var(--color-text);
}

/* Tutorial Grid */
.tutorials-grid {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 24px 80px;
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(340px, 1fr));
  gap: 24px;
}

.tutorial-card {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  padding: 28px;
  transition: all var(--transition);
  display: flex;
  flex-direction: column;
  text-decoration: none;
  color: inherit;
}

.tutorial-card:hover {
  box-shadow: var(--shadow-md);
  border-color: #ccc;
  transform: translateY(-2px);
  color: inherit;
}

.card-meta {
  display: flex;
  align-items: center;
  gap: 8px;
  margin-bottom: 14px;
  flex-wrap: wrap;
}

.card-tag {
  font-size: 0.75rem;
  font-weight: 500;
  color: var(--color-tag-text);
  background: var(--color-tag-bg);
  padding: 3px 10px;
  border-radius: 12px;
}

.card-tag.product {
  background: #E8F0FE;
  color: #1967D2;
}

.card-time {
  font-size: 0.75rem;
  color: var(--color-text-tertiary);
  margin-left: auto;
}

.tutorial-card h2 {
  font-size: 1.125rem;
  font-weight: 600;
  line-height: 1.4;
  margin-bottom: 10px;
}

.tutorial-card p {
  font-size: 0.9rem;
  color: var(--color-text-secondary);
  line-height: 1.6;
  flex: 1;
}

.card-arrow {
  margin-top: 16px;
  color: var(--color-text-tertiary);
  font-size: 0.85rem;
  font-weight: 500;
  display: flex;
  align-items: center;
  gap: 4px;
  transition: color var(--transition);
}

.tutorial-card:hover .card-arrow {
  color: var(--color-accent);
}

/* Article Page */
.article-header {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 48px 24px 0;
}

.breadcrumb {
  font-size: 0.85rem;
  color: var(--color-text-tertiary);
  margin-bottom: 24px;
}

.breadcrumb a {
  color: var(--color-text-secondary);
}

.breadcrumb a:hover {
  color: var(--color-accent);
}

.article-header h1 {
  font-size: 2.25rem;
  font-weight: 700;
  line-height: 1.25;
  letter-spacing: -0.02em;
  max-width: var(--max-width-article);
  margin-bottom: 16px;
}

.article-meta {
  display: flex;
  align-items: center;
  gap: 12px;
  margin-bottom: 40px;
  flex-wrap: wrap;
}

.article-content {
  max-width: var(--max-width-article);
  margin: 0 auto;
  padding: 0 24px 80px;
}

.article-content h2 {
  font-size: 1.5rem;
  font-weight: 650;
  margin: 48px 0 16px;
  letter-spacing: -0.01em;
}

.article-content h3 {
  font-size: 1.2rem;
  font-weight: 600;
  margin: 32px 0 12px;
}

.article-content h4 {
  font-size: 1.05rem;
  font-weight: 600;
  margin: 24px 0 8px;
}

.article-content p {
  margin-bottom: 16px;
  font-size: 1rem;
  line-height: 1.8;
}

.article-content ul,
.article-content ol {
  margin-bottom: 16px;
  padding-left: 24px;
}

.article-content li {
  margin-bottom: 8px;
  line-height: 1.7;
}

.article-content blockquote {
  border-left: 3px solid var(--color-accent);
  padding: 16px 20px;
  margin: 24px 0;
  background: var(--color-tag-bg);
  border-radius: 0 var(--radius) var(--radius) 0;
  font-size: 0.95rem;
  color: var(--color-text-secondary);
}

.article-content code {
  font-family: var(--font-mono);
  font-size: 0.875em;
  background: var(--color-tag-bg);
  padding: 2px 6px;
  border-radius: 4px;
}

.article-content pre {
  background: #1E1E1E;
  color: #D4D4D4;
  padding: 20px;
  border-radius: var(--radius);
  overflow-x: auto;
  margin: 24px 0;
  font-size: 0.875rem;
  line-height: 1.6;
}

.article-content pre code {
  background: none;
  padding: 0;
  color: inherit;
}

.article-content table {
  width: 100%;
  border-collapse: collapse;
  margin: 24px 0;
  font-size: 0.9rem;
}

.article-content th,
.article-content td {
  border: 1px solid var(--color-border);
  padding: 12px 16px;
  text-align: left;
}

.article-content th {
  background: var(--color-tag-bg);
  font-weight: 600;
}

.tip-box {
  border: 1px solid #BEE3F8;
  background: #EBF8FF;
  border-radius: var(--radius);
  padding: 20px;
  margin: 24px 0;
}

.tip-box .tip-title {
  font-weight: 600;
  font-size: 0.9rem;
  margin-bottom: 8px;
  color: #2B6CB0;
}

.warning-box {
  border: 1px solid #FEEBC8;
  background: #FFFBEB;
  border-radius: var(--radius);
  padding: 20px;
  margin: 24px 0;
}

.warning-box .warning-title {
  font-weight: 600;
  font-size: 0.9rem;
  margin-bottom: 8px;
  color: #C05621;
}

/* Related Articles */
.related-section {
  max-width: var(--max-width-article);
  margin: 0 auto;
  padding: 0 24px 80px;
  border-top: 1px solid var(--color-border);
  padding-top: 40px;
}

.related-section h3 {
  font-size: 1.2rem;
  font-weight: 600;
  margin-bottom: 20px;
}

.related-list {
  display: flex;
  flex-direction: column;
  gap: 12px;
}

.related-list a {
  display: flex;
  align-items: center;
  gap: 8px;
  padding: 12px 16px;
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  font-size: 0.9rem;
  font-weight: 500;
  transition: all var(--transition);
}

.related-list a:hover {
  background: var(--color-tag-bg);
  border-color: #ccc;
}

/* Footer */
.site-footer {
  background: var(--color-text);
  color: var(--color-surface);
  padding: 48px 24px;
}

.footer-inner {
  max-width: var(--max-width);
  margin: 0 auto;
  display: flex;
  justify-content: space-between;
  align-items: flex-start;
  gap: 40px;
  flex-wrap: wrap;
}

.footer-brand {
  font-size: 0.95rem;
  color: #999;
  max-width: 360px;
  line-height: 1.6;
}

.footer-brand strong {
  color: var(--color-surface);
  display: block;
  margin-bottom: 8px;
  font-size: 1rem;
}

.footer-links {
  display: flex;
  gap: 48px;
}

.footer-col h4 {
  font-size: 0.8rem;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: #999;
  margin-bottom: 12px;
  font-weight: 600;
}

.footer-col a {
  display: block;
  font-size: 0.875rem;
  color: #CCC;
  margin-bottom: 8px;
}

.footer-col a:hover {
  color: var(--color-surface);
}

.footer-bottom {
  max-width: var(--max-width);
  margin: 32px auto 0;
  padding-top: 24px;
  border-top: 1px solid #333;
  font-size: 0.8rem;
  color: #666;
  text-align: center;
}

/* Flow Diagram */
.flow-diagram {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 0;
  margin: 32px 0;
  padding: 24px 16px;
  background: linear-gradient(135deg, #F8FAFC 0%, #EFF6FF 100%);
  border-radius: 12px;
  border: 1px solid #DBEAFE;
  overflow-x: auto;
}

.flow-step {
  display: flex;
  flex-direction: column;
  align-items: center;
  text-align: center;
  min-width: 110px;
  flex-shrink: 0;
}

.flow-icon {
  width: 56px;
  height: 56px;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.5rem;
  margin-bottom: 10px;
  box-shadow: 0 2px 8px rgba(0,0,0,0.08);
  border: 3px solid white;
}

.flow-icon.blue { background: linear-gradient(135deg, #3B82F6, #2563EB); color: white; }
.flow-icon.green { background: linear-gradient(135deg, #10B981, #059669); color: white; }
.flow-icon.purple { background: linear-gradient(135deg, #8B5CF6, #7C3AED); color: white; }
.flow-icon.orange { background: linear-gradient(135deg, #F59E0B, #D97706); color: white; }
.flow-icon.red { background: linear-gradient(135deg, #EF4444, #DC2626); color: white; }
.flow-icon.teal { background: linear-gradient(135deg, #14B8A6, #0D9488); color: white; }
.flow-icon.pink { background: linear-gradient(135deg, #EC4899, #DB2777); color: white; }

.flow-label {
  font-size: 0.8rem;
  font-weight: 600;
  color: var(--color-text);
  line-height: 1.3;
}

.flow-sublabel {
  font-size: 0.7rem;
  color: var(--color-text-secondary);
  margin-top: 2px;
}

.flow-arrow {
  font-size: 1.5rem;
  color: #93C5FD;
  flex-shrink: 0;
  margin: 0 4px;
  padding-bottom: 24px;
}

/* Vertical Flow */
.flow-vertical {
  flex-direction: column;
  gap: 0;
}

.flow-vertical .flow-arrow {
  transform: rotate(90deg);
  margin: 4px 0;
  padding-bottom: 0;
}

/* Feature Cards Grid */
.feature-cards {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: 16px;
  margin: 24px 0;
}

.feature-card {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: 10px;
  padding: 20px;
  transition: all var(--transition);
  position: relative;
  overflow: hidden;
}

.feature-card::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 3px;
}

.feature-card.card-blue::before { background: linear-gradient(90deg, #3B82F6, #60A5FA); }
.feature-card.card-green::before { background: linear-gradient(90deg, #10B981, #34D399); }
.feature-card.card-purple::before { background: linear-gradient(90deg, #8B5CF6, #A78BFA); }
.feature-card.card-orange::before { background: linear-gradient(90deg, #F59E0B, #FBBF24); }
.feature-card.card-red::before { background: linear-gradient(90deg, #EF4444, #F87171); }
.feature-card.card-teal::before { background: linear-gradient(90deg, #14B8A6, #2DD4BF); }
.feature-card.card-pink::before { background: linear-gradient(90deg, #EC4899, #F472B6); }

.feature-card:hover {
  transform: translateY(-2px);
  box-shadow: var(--shadow-md);
}

.feature-card-icon {
  font-size: 1.8rem;
  margin-bottom: 12px;
}

.feature-card h4 {
  font-size: 0.95rem;
  font-weight: 600;
  margin-bottom: 6px;
  margin-top: 0;
}

.feature-card p {
  font-size: 0.85rem;
  color: var(--color-text-secondary);
  line-height: 1.5;
  margin-bottom: 0;
}

/* Comparison Blocks */
.compare-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 16px;
  margin: 24px 0;
}

.compare-block {
  border-radius: 10px;
  padding: 20px;
  border: 1px solid;
}

.compare-block.block-good {
  background: #F0FDF4;
  border-color: #BBF7D0;
}

.compare-block.block-caution {
  background: #FFFBEB;
  border-color: #FDE68A;
}

.compare-block.block-info {
  background: #EFF6FF;
  border-color: #BFDBFE;
}

.compare-block.block-neutral {
  background: #F8FAFC;
  border-color: #E2E8F0;
}

.compare-block h4 {
  font-size: 0.95rem;
  font-weight: 600;
  margin: 0 0 10px 0;
  display: flex;
  align-items: center;
  gap: 6px;
}

.compare-block ul {
  margin: 0;
  padding-left: 18px;
}

.compare-block li {
  font-size: 0.88rem;
  line-height: 1.6;
  margin-bottom: 4px;
}

/* Info/Tip/Warning/Note Boxes */
.info-box {
  border-radius: 10px;
  padding: 20px 24px;
  margin: 24px 0;
  border-left: 4px solid;
  display: flex;
  gap: 14px;
}

.info-box .info-icon {
  font-size: 1.4rem;
  flex-shrink: 0;
  margin-top: 2px;
}

.info-box .info-content {
  flex: 1;
}

.info-box .info-content strong {
  display: block;
  margin-bottom: 4px;
  font-size: 0.9rem;
}

.info-box .info-content p {
  margin: 0;
  font-size: 0.9rem;
  line-height: 1.6;
}

.info-box.box-tip {
  background: #EFF6FF;
  border-color: #3B82F6;
}

.info-box.box-tip .info-content strong { color: #1D4ED8; }

.info-box.box-warning {
  background: #FFFBEB;
  border-color: #F59E0B;
}

.info-box.box-warning .info-content strong { color: #B45309; }

.info-box.box-success {
  background: #F0FDF4;
  border-color: #10B981;
}

.info-box.box-success .info-content strong { color: #047857; }

.info-box.box-note {
  background: #FAF5FF;
  border-color: #8B5CF6;
}

.info-box.box-note .info-content strong { color: #6D28D9; }

/* Model Cards (for model comparison) */
.model-cards {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 16px;
  margin: 24px 0;
}

.model-card {
  border-radius: 12px;
  padding: 24px;
  border: 2px solid;
  text-align: center;
  position: relative;
}

.model-card.model-haiku {
  background: linear-gradient(135deg, #ECFDF5 0%, #D1FAE5 100%);
  border-color: #6EE7B7;
}

.model-card.model-sonnet {
  background: linear-gradient(135deg, #EFF6FF 0%, #DBEAFE 100%);
  border-color: #93C5FD;
}

.model-card.model-opus {
  background: linear-gradient(135deg, #FAF5FF 0%, #EDE9FE 100%);
  border-color: #C4B5FD;
}

.model-card .model-emoji {
  font-size: 2.2rem;
  margin-bottom: 10px;
}

.model-card h4 {
  font-size: 1.1rem;
  font-weight: 700;
  margin: 0 0 4px 0;
}

.model-card .model-version {
  font-size: 0.75rem;
  color: var(--color-text-tertiary);
  margin-bottom: 10px;
}

.model-card .model-desc {
  font-size: 0.85rem;
  color: var(--color-text-secondary);
  line-height: 1.5;
  margin-bottom: 12px;
}

.model-card .model-badge {
  display: inline-block;
  padding: 3px 12px;
  border-radius: 12px;
  font-size: 0.75rem;
  font-weight: 600;
}

.model-haiku .model-badge {
  background: #D1FAE5;
  color: #047857;
}

.model-sonnet .model-badge {
  background: #DBEAFE;
  color: #1D4ED8;
}

.model-opus .model-badge {
  background: #EDE9FE;
  color: #6D28D9;
}

/* Stepped Process */
.step-list {
  margin: 24px 0;
  padding: 0;
  list-style: none;
  counter-reset: step-counter;
}

.step-item {
  display: flex;
  gap: 16px;
  margin-bottom: 20px;
  position: relative;
}

.step-item::before {
  counter-increment: step-counter;
  content: counter(step-counter);
  width: 36px;
  height: 36px;
  border-radius: 50%;
  background: linear-gradient(135deg, #3B82F6, #2563EB);
  color: white;
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 700;
  font-size: 0.9rem;
  flex-shrink: 0;
  box-shadow: 0 2px 6px rgba(59,130,246,0.3);
}

.step-item:not(:last-child)::after {
  content: '';
  position: absolute;
  left: 17px;
  top: 40px;
  bottom: -16px;
  width: 2px;
  background: linear-gradient(to bottom, #93C5FD, #DBEAFE);
}

.step-content h4 {
  font-size: 1rem;
  font-weight: 600;
  margin: 4px 0 6px 0;
}

.step-content p {
  font-size: 0.9rem;
  color: var(--color-text-secondary);
  line-height: 1.6;
  margin: 0;
}

/* Architecture Diagram */
.arch-diagram {
  background: linear-gradient(135deg, #F8FAFC 0%, #F1F5F9 100%);
  border: 1px solid #E2E8F0;
  border-radius: 12px;
  padding: 32px 24px;
  margin: 32px 0;
  text-align: center;
}

.arch-diagram .arch-title {
  font-size: 0.85rem;
  font-weight: 600;
  color: var(--color-text-secondary);
  text-transform: uppercase;
  letter-spacing: 0.05em;
  margin-bottom: 20px;
}

.arch-row {
  display: flex;
  justify-content: center;
  gap: 12px;
  margin-bottom: 12px;
  flex-wrap: wrap;
}

.arch-box {
  padding: 10px 20px;
  border-radius: 8px;
  font-size: 0.85rem;
  font-weight: 600;
  border: 2px solid;
  min-width: 120px;
}

.arch-box.box-primary {
  background: #EFF6FF;
  border-color: #3B82F6;
  color: #1D4ED8;
}

.arch-box.box-secondary {
  background: #F0FDF4;
  border-color: #10B981;
  color: #047857;
}

.arch-box.box-tertiary {
  background: #FAF5FF;
  border-color: #8B5CF6;
  color: #6D28D9;
}

.arch-box.box-accent {
  background: #FFFBEB;
  border-color: #F59E0B;
  color: #B45309;
}

.arch-connector {
  font-size: 1.2rem;
  color: #94A3B8;
  margin: 4px 0;
}

/* Stat Highlights */
.stat-row {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(140px, 1fr));
  gap: 16px;
  margin: 24px 0;
}

.stat-item {
  text-align: center;
  padding: 20px 12px;
  border-radius: 10px;
  background: var(--color-surface);
  border: 1px solid var(--color-border);
}

.stat-number {
  font-size: 1.8rem;
  font-weight: 800;
  letter-spacing: -0.02em;
  line-height: 1;
  margin-bottom: 4px;
}

.stat-number.text-blue { color: #2563EB; }
.stat-number.text-green { color: #059669; }
.stat-number.text-purple { color: #7C3AED; }
.stat-number.text-orange { color: #D97706; }

.stat-label {
  font-size: 0.8rem;
  color: var(--color-text-secondary);
  font-weight: 500;
}

/* Colorful Table */
.article-content table.styled-table {
  border: none;
  border-radius: 10px;
  overflow: hidden;
  box-shadow: var(--shadow-sm);
}

.article-content table.styled-table th {
  background: linear-gradient(135deg, #1E293B, #334155);
  color: white;
  border: none;
  font-size: 0.85rem;
  padding: 14px 16px;
}

.article-content table.styled-table td {
  border: none;
  border-bottom: 1px solid #F1F5F9;
  padding: 14px 16px;
  font-size: 0.88rem;
}

.article-content table.styled-table tr:nth-child(even) {
  background: #F8FAFC;
}

.article-content table.styled-table tr:hover {
  background: #EFF6FF;
}

/* Badge Inline */
.badge {
  display: inline-block;
  padding: 2px 10px;
  border-radius: 12px;
  font-size: 0.75rem;
  font-weight: 600;
}

.badge-blue { background: #DBEAFE; color: #1D4ED8; }
.badge-green { background: #D1FAE5; color: #047857; }
.badge-purple { background: #EDE9FE; color: #6D28D9; }
.badge-orange { background: #FEF3C7; color: #B45309; }
.badge-red { background: #FEE2E2; color: #B91C1C; }

/* Responsive adjustments for new components */
@media (max-width: 768px) {
  .model-cards {
    grid-template-columns: 1fr;
  }

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

  .flow-diagram {
    justify-content: flex-start;
    padding: 16px 12px;
  }

  .feature-cards {
    grid-template-columns: 1fr;
  }

  .stat-row {
    grid-template-columns: repeat(2, 1fr);
  }

  .arch-row {
    flex-direction: column;
    align-items: center;
  }
}

/* Responsive */
@media (max-width: 768px) {
  .hero h1 {
    font-size: 1.75rem;
  }

  .hero p {
    font-size: 1rem;
  }

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

  .article-header h1 {
    font-size: 1.65rem;
  }

  .header-nav {
    gap: 12px;
  }

  .footer-links {
    gap: 24px;
  }

  .footer-inner {
    flex-direction: column;
  }

  .filter-bar {
    overflow-x: auto;
    flex-wrap: nowrap;
    -webkit-overflow-scrolling: touch;
  }

  .filter-btn {
    white-space: nowrap;
    flex-shrink: 0;
  }
}

@media (max-width: 480px) {
  .header-inner {
    padding: 0 16px;
  }

  .hero {
    padding: 40px 16px 32px;
  }

  .tutorials-grid {
    padding: 0 16px 60px;
  }

  .article-content {
    padding: 0 16px 60px;
  }

  .article-header {
    padding: 32px 16px 0;
  }
}

/* ===== Table of Contents (目次) ===== */
.toc {
  margin: 32px 0 8px;
  padding: 20px 24px;
  background: var(--color-tag-bg);
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
}
.toc-title {
  font-size: 0.8rem;
  font-weight: 700;
  letter-spacing: 0.04em;
  text-transform: uppercase;
  color: var(--color-text-secondary);
  margin: 0 0 12px;
}
.toc ol {
  margin: 0;
  padding-left: 1.2em;
  display: flex;
  flex-direction: column;
  gap: 6px;
}
.toc ol li {
  font-size: 0.92rem;
  line-height: 1.5;
}
.toc ol li a {
  color: var(--color-text-secondary);
  text-decoration: none;
  transition: color var(--transition);
}
.toc ol li a:hover {
  color: var(--color-accent);
  text-decoration: underline;
}
html { scroll-behavior: smooth; }
.article-content h2[id] { scroll-margin-top: 80px; }

/* ===== Prev / Next article navigation ===== */
.article-nav {
  max-width: var(--max-width-article);
  margin: 0 auto;
  padding: 0 24px;
  display: flex;
  gap: 16px;
  justify-content: space-between;
}
.article-nav a {
  flex: 1 1 0;
  display: flex;
  flex-direction: column;
  gap: 4px;
  padding: 16px 18px;
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  text-decoration: none;
  transition: all var(--transition);
  background: var(--color-surface);
  min-width: 0;
}
.article-nav a:hover {
  border-color: var(--color-accent);
  box-shadow: var(--shadow-md);
}
.article-nav .nav-next { text-align: right; }
.article-nav .nav-dir {
  font-size: 0.78rem;
  font-weight: 600;
  color: var(--color-accent);
}
.article-nav .nav-title {
  font-size: 0.92rem;
  font-weight: 600;
  color: var(--color-text);
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}
.article-nav .nav-empty {
  flex: 1 1 0;
  border: none;
  background: none;
  box-shadow: none;
}

@media (max-width: 640px) {
  .article-nav { flex-direction: column; }
  .article-nav .nav-next { text-align: left; }
  .article-nav .nav-empty { display: none; }
}
@media (max-width: 480px) {
  .toc { padding: 16px; margin-left: 0; margin-right: 0; }
  .article-nav { padding: 0 16px; }
}