/* ═══════════════════════════════════════
   LAYOUT · 页面布局
   ═══════════════════════════════════════ */

/* ── Navbar ── */
.navbar {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  height: var(--navbar-height);
  z-index: var(--z-nav);
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0 var(--space-2xl);
  background: var(--color-bg-primary);
  border-bottom: 1px solid transparent;
  transition: border-color var(--duration-normal), background var(--duration-normal), backdrop-filter var(--duration-normal);
}

.navbar.scrolled {
  border-bottom-color: var(--color-border);
  background: rgba(250, 248, 245, 0.85);
  backdrop-filter: blur(20px) saturate(180%);
  -webkit-backdrop-filter: blur(20px) saturate(180%);
}

[data-theme="dark"] .navbar.scrolled {
  background: rgba(18, 18, 18, 0.85);
  backdrop-filter: blur(20px) saturate(180%);
}

.nav-brand {
  font-family: var(--font-display);
  font-size: var(--text-xl);
  font-weight: 900;
  letter-spacing: 0.08em;
  color: var(--color-text-primary);
  white-space: nowrap;
}

.nav-brand-dot {
  color: var(--color-accent);
}

.nav-categories {
  display: flex;
  gap: var(--space-xs);
  align-items: center;
}

.nav-controls {
  display: flex;
  align-items: center;
  gap: var(--space-md);
}

/* ── Hero Section (compact banner) ── */
.hero {
  margin-top: var(--navbar-height);
  padding: var(--space-3xl) var(--space-2xl);
  border-bottom: 1px solid var(--color-border);
  background: var(--color-bg-primary);
}

.hero-inner {
  max-width: var(--content-max-width);
  margin: 0 auto;
}

.hero-label {
  display: inline-block;
  font-family: var(--font-sans);
  font-size: var(--text-xs);
  font-weight: 600;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--color-accent);
  margin-bottom: var(--space-md);
}

.hero-title {
  font-family: var(--font-display);
  font-size: var(--text-3xl);
  font-weight: 900;
  line-height: var(--leading-tight);
  color: var(--color-text-primary);
  margin-bottom: var(--space-md);
  max-width: 900px;
}

.hero-title a:hover {
  color: var(--color-accent);
  transition: color 0.2s;
}

.hero-sub {
  font-size: var(--text-lg);
  line-height: var(--leading-relaxed);
  color: var(--color-text-secondary);
  max-width: 700px;
  margin-bottom: var(--space-lg);
}

.hero-meta {
  display: flex;
  align-items: center;
  gap: var(--space-sm);
  font-family: var(--font-sans);
  font-size: var(--text-sm);
  color: var(--color-text-tertiary);
}

/* ── Main Content Layout ── */
.content-wrapper {
  max-width: var(--content-max-width);
  margin: 0 auto;
  padding: var(--space-3xl) var(--space-2xl);
  display: grid;
  grid-template-columns: var(--sidebar-width) 1fr;
  gap: var(--space-3xl);
  align-items: start;
}

/* ── Sidebar ── */
.sidebar {
  position: sticky;
  top: calc(var(--navbar-height) + var(--space-2xl));
}

.sidebar-section {
  margin-bottom: var(--space-2xl);
}

.sidebar-title {
  font-family: var(--font-sans);
  font-size: var(--text-xs);
  font-weight: 600;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--color-text-tertiary);
  margin-bottom: var(--space-md);
  padding-bottom: var(--space-sm);
  border-bottom: 1px solid var(--color-border);
}

.sidebar-categories {
  display: flex;
  flex-direction: column;
  gap: 2px;
}

.category-item {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 10px 14px;
  border-radius: var(--radius-sm);
  font-family: var(--font-sans);
  font-size: var(--text-sm);
  font-weight: 500;
  color: var(--color-text-secondary);
  cursor: pointer;
  transition: all var(--duration-fast);
}

.category-item:hover {
  background: var(--color-accent-subtle);
  color: var(--color-text-primary);
}

.category-item.active {
  background: var(--color-accent);
  color: #FFFFFF;
  font-weight: 600;
}

.category-count {
  font-size: var(--text-xs);
  color: var(--color-text-tertiary);
  min-width: 24px;
  text-align: center;
}

.category-item.active .category-count {
  color: rgba(255, 255, 255, 0.8);
}

/* ── Source Legend ── */
.source-legend {
  display: flex;
  flex-direction: column;
  gap: 6px;
}

.source-item {
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 6px 0;
  font-size: var(--text-sm);
  color: var(--color-text-secondary);
}

.source-dot {
  width: 8px;
  height: 8px;
  border-radius: 50%;
  flex-shrink: 0;
}

/* ── News Grid ── */
.news-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: var(--grid-gap);
}

.news-grid-header {
  grid-column: 1 / -1;
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: var(--space-md);
}

.section-title {
  font-family: var(--font-display);
  font-size: var(--text-2xl);
  font-weight: 700;
  color: var(--color-text-primary);
}

.section-title::after {
  content: '';
  display: block;
  width: 40px;
  height: 3px;
  background: var(--color-accent);
  margin-top: var(--space-sm);
}

/* ── Stats Bar ── */
.stats-bar {
  max-width: var(--content-max-width);
  margin: 0 auto;
  padding: var(--space-xl) var(--space-2xl);
  border-top: 1px solid var(--color-border);
  display: flex;
  justify-content: center;
  gap: var(--space-3xl);
}

.stat-item {
  text-align: center;
}

.stat-value {
  font-family: var(--font-display);
  font-size: var(--text-2xl);
  font-weight: 700;
  color: var(--color-accent);
}

.stat-label {
  font-family: var(--font-sans);
  font-size: var(--text-xs);
  color: var(--color-text-tertiary);
  margin-top: var(--space-xs);
  text-transform: uppercase;
  letter-spacing: 0.08em;
}

/* ── Footer ── */
.site-footer {
  border-top: 1px solid var(--color-border);
  padding: var(--space-3xl) var(--space-2xl);
  text-align: center;
}

.footer-inner {
  max-width: var(--content-max-width);
  margin: 0 auto;
}

.footer-brand {
  font-family: var(--font-display);
  font-size: var(--text-lg);
  font-weight: 700;
  margin-bottom: var(--space-sm);
}

.footer-tagline {
  font-size: var(--text-sm);
  color: var(--color-text-tertiary);
  margin-bottom: var(--space-lg);
}

.footer-disclaimer {
  font-size: var(--text-xs);
  color: var(--color-text-tertiary);
  opacity: 0.6;
}

/* ── Empty State ── */
.empty-state {
  grid-column: 1 / -1;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  padding: var(--space-4xl) var(--space-2xl);
  text-align: center;
}

.empty-icon {
  font-size: 4rem;
  margin-bottom: var(--space-lg);
  opacity: 0.3;
}

.empty-title {
  font-family: var(--font-display);
  font-size: var(--text-xl);
  font-weight: 600;
  margin-bottom: var(--space-sm);
}

.empty-desc {
  font-size: var(--text-base);
  color: var(--color-text-tertiary);
  max-width: 400px;
}

/* ── Loading State ── */
.loading-shimmer {
  grid-column: 1 / -1;
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: var(--grid-gap);
}

.shimmer-card {
  border-radius: var(--radius-md);
  overflow: hidden;
  background: var(--color-bg-secondary);
}

.shimmer-image {
  width: 100%;
  aspect-ratio: 16/10;
  background: linear-gradient(90deg, var(--color-bg-tertiary) 25%, var(--color-bg-secondary) 50%, var(--color-bg-tertiary) 75%);
  background-size: 200% 100%;
  animation: shimmer 1.5s infinite;
}

.shimmer-body {
  padding: var(--space-lg);
}

.shimmer-line {
  height: 14px;
  margin-bottom: 10px;
  border-radius: 4px;
  background: linear-gradient(90deg, var(--color-bg-tertiary) 25%, var(--color-bg-secondary) 50%, var(--color-bg-tertiary) 75%);
  background-size: 200% 100%;
  animation: shimmer 1.5s infinite;
}

.shimmer-line:first-child { width: 80%; }
.shimmer-line:nth-child(2) { width: 100%; }
.shimmer-line:nth-child(3) { width: 60%; }

@keyframes shimmer {
  0% { background-position: 200% 0; }
  100% { background-position: -200% 0; }
}

/* ── Offline Banner ── */
.offline-banner {
  position: fixed;
  top: var(--navbar-height);
  left: 0;
  right: 0;
  z-index: calc(var(--z-nav) - 1);
  background: var(--color-accent);
  color: #FFFFFF;
  text-align: center;
  padding: 8px var(--space-md);
  font-family: var(--font-sans);
  font-size: var(--text-xs);
  font-weight: 500;
  letter-spacing: 0.04em;
  transform: translateY(-100%);
  transition: transform var(--duration-normal);
}

.offline-banner.show {
  transform: translateY(0);
}