:root {
  --color-primary: #6366f1;
  --color-primary-hover: #818cf8;
  --color-primary-light: rgba(99, 102, 241, 0.08);
  --color-bg: #f8fafc;
  --color-bg-card: #ffffff;
  --color-bg-card-hover: #f1f5f9;
  --color-bg-section: #f1f5f9;
  --color-border: #e2e8f0;
  --color-text: #1e293b;
  --color-text-secondary: #64748b;
  --color-text-muted: #94a3b8;
}

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

html {
  scroll-behavior: smooth;
  scroll-padding-top: 80px;
}

body {
  font-family: 'Noto Sans TC', 'Segoe UI', system-ui, -apple-system, sans-serif;
  background-color: var(--color-bg);
  color: var(--color-text);
  line-height: 1.7;
}

::-webkit-scrollbar {
  width: 8px;
}
::-webkit-scrollbar-track {
  background: var(--color-bg);
}
::-webkit-scrollbar-thumb {
  background: #cbd5e1;
  border-radius: 4px;
}
::-webkit-scrollbar-thumb:hover {
  background: var(--color-primary);
}

a {
  color: var(--color-primary);
  text-decoration: none;
  transition: color 0.2s;
}
a:hover {
  color: var(--color-primary-hover);
}

.card {
  background: var(--color-bg-card);
  border: 1px solid var(--color-border);
  border-radius: 12px;
  transition: transform 0.2s, border-color 0.2s, box-shadow 0.2s;
  overflow: hidden;
}
.card:hover {
  transform: translateY(-4px);
  border-color: var(--color-primary);
  box-shadow: 0 8px 30px rgba(99, 102, 241, 0.12);
}

.card-image {
  width: 100%;
  aspect-ratio: 16 / 9;
  object-fit: cover;
  background: linear-gradient(135deg, #eef2ff, #ede9fe);
}

.badge {
  display: inline-block;
  padding: 2px 10px;
  border-radius: 9999px;
  font-size: 0.75rem;
  font-weight: 600;
  line-height: 1.6;
}

.badge-purple {
  background: rgba(99, 102, 241, 0.12);
  color: var(--color-primary);
  border: 1px solid rgba(99, 102, 241, 0.25);
}

.badge-green {
  background: rgba(16, 185, 129, 0.12);
  color: #059669;
  border: 1px solid rgba(16, 185, 129, 0.25);
}

.badge-blue {
  background: rgba(59, 130, 246, 0.12);
  color: #2563eb;
  border: 1px solid rgba(59, 130, 246, 0.25);
}

.badge-orange {
  background: rgba(245, 158, 11, 0.12);
  color: #d97706;
  border: 1px solid rgba(245, 158, 11, 0.25);
}

.navbar {
  background: rgba(255, 255, 255, 0.9);
  backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--color-border);
  position: sticky;
  top: 0;
  z-index: 100;
  transition: box-shadow 0.3s;
}

.navbar.scrolled {
  box-shadow: 0 4px 20px rgba(0, 0, 0, 0.06);
}

.nav-link {
  color: var(--color-text-secondary);
  padding: 8px 16px;
  border-radius: 8px;
  font-size: 0.9rem;
  font-weight: 500;
  transition: color 0.2s, background 0.2s;
}

.nav-link:hover,
.nav-link.active {
  color: var(--color-primary);
  background: rgba(99, 102, 241, 0.08);
}

.nav-link.active {
  font-weight: 600;
}

.mobile-menu {
  transform: translateX(100%);
  transition: transform 0.3s ease;
}

.mobile-menu.open {
  transform: translateX(0);
}

.hero {
  position: relative;
  overflow: hidden;
  background: linear-gradient(135deg, #eef2ff 0%, #ede9fe 50%, #f0fdf4 100%);
}

.hero::before {
  content: '';
  position: absolute;
  inset: 0;
  background:
    radial-gradient(ellipse at 20% 50%, rgba(99, 102, 241, 0.08) 0%, transparent 50%),
    radial-gradient(ellipse at 80% 50%, rgba(139, 92, 246, 0.06) 0%, transparent 50%);
  pointer-events: none;
}

.hero-glow {
  position: absolute;
  width: 400px;
  height: 400px;
  border-radius: 50%;
  filter: blur(100px);
  opacity: 0.15;
  pointer-events: none;
}

.toc {
  position: sticky;
  top: 80px;
}

.toc-item {
  display: block;
  padding: 6px 12px;
  border-left: 2px solid var(--color-border);
  color: var(--color-text-muted);
  font-size: 0.85rem;
  transition: all 0.2s;
}

.toc-item:hover {
  color: var(--color-text);
  border-left-color: var(--color-text-muted);
}

.toc-item.active {
  color: var(--color-primary);
  border-left-color: var(--color-primary);
  background: rgba(99, 102, 241, 0.06);
  border-radius: 0 6px 6px 0;
}

.article-content h2 {
  font-size: 1.5rem;
  font-weight: 700;
  margin-top: 2.5rem;
  margin-bottom: 1rem;
  padding-bottom: 0.5rem;
  border-bottom: 1px solid var(--color-border);
  color: var(--color-text);
}

.article-content h3 {
  font-size: 1.2rem;
  font-weight: 600;
  margin-top: 2rem;
  margin-bottom: 0.75rem;
  color: #334155;
}

.article-content p {
  margin-bottom: 1rem;
  color: var(--color-text);
}

.article-content ul,
.article-content ol {
  margin-bottom: 1rem;
  padding-left: 1.5rem;
}

.article-content li {
  margin-bottom: 0.4rem;
}

.article-content strong {
  color: #0f172a;
}

.article-content code {
  background: rgba(99, 102, 241, 0.1);
  padding: 2px 6px;
  border-radius: 4px;
  font-size: 0.88em;
  color: var(--color-primary);
}

.article-content blockquote {
  border-left: 3px solid var(--color-primary);
  padding: 12px 16px;
  margin: 1rem 0;
  background: rgba(99, 102, 241, 0.04);
  border-radius: 0 8px 8px 0;
  color: var(--color-text-secondary);
  font-style: italic;
}

.article-content table {
  width: 100%;
  border-collapse: collapse;
  margin: 1rem 0;
  font-size: 0.9rem;
}

.article-content th,
.article-content td {
  padding: 10px 14px;
  border: 1px solid var(--color-border);
  text-align: left;
}

.article-content th {
  background: rgba(99, 102, 241, 0.06);
  color: var(--color-text);
  font-weight: 600;
}

.article-content tr:hover td {
  background: rgba(99, 102, 241, 0.03);
}

.ad-slot {
  background: linear-gradient(135deg, #f1f5f9, #e2e8f0);
  border: 2px dashed var(--color-border);
  border-radius: 12px;
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--color-text-muted);
  font-size: 0.8rem;
  letter-spacing: 2px;
  min-height: 90px;
  transition: border-color 0.3s;
}

.ad-slot:hover {
  border-color: var(--color-primary);
}

footer {
  background: #ffffff;
  border-top: 1px solid var(--color-border);
}

.breadcrumb-item + .breadcrumb-item::before {
  content: '\203A';
  color: var(--color-text-muted);
  margin: 0 8px;
}

.category-pill {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 6px 14px;
  border-radius: 9999px;
  background: var(--color-bg-card);
  border: 1px solid var(--color-border);
  color: var(--color-text-secondary);
  font-size: 0.85rem;
  font-weight: 500;
  transition: all 0.2s;
  cursor: pointer;
}

.category-pill:hover,
.category-pill.active {
  background: rgba(99, 102, 241, 0.1);
  border-color: var(--color-primary);
  color: var(--color-primary);
}

.back-to-top {
  position: fixed;
  bottom: 24px;
  right: 24px;
  width: 44px;
  height: 44px;
  border-radius: 12px;
  background: var(--color-primary);
  color: #fff;
  display: flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  opacity: 0;
  visibility: hidden;
  transform: translateY(10px);
  transition: all 0.3s;
  z-index: 50;
  border: none;
  box-shadow: 0 4px 15px rgba(99, 102, 241, 0.3);
}

.back-to-top.visible {
  opacity: 1;
  visibility: visible;
  transform: translateY(0);
}

.back-to-top:hover {
  background: var(--color-primary-hover);
}

@keyframes fadeInUp {
  from { opacity: 0; transform: translateY(20px); }
  to { opacity: 1; transform: translateY(0); }
}

.animate-fade-in-up {
  animation: fadeInUp 0.5s ease forwards;
}

@media (max-width: 1024px) {
  .toc { display: none; }
}

@media (max-width: 768px) {
  .hero h1 { font-size: 1.75rem !important; }
  .article-content h2 { font-size: 1.25rem; }
  .article-content h3 { font-size: 1.05rem; }
}