/* MANDATORY: Apply color-scheme to :root for viewport-wide theming */
:root {
  --bg-canvas-light: #f8fafc;
  --bg-canvas-dark: #090d16;
  --bg-surface-light: #ffffff;
  --bg-surface-dark: #111827;
  --bg-elevated-light: #f1f5f9;
  --bg-elevated-dark: #1e293b;
  --text-primary-light: #0f172a;
  --text-primary-dark: #f8fafc;
  --text-secondary-light: #475569;
  --text-secondary-dark: #94a3b8;
  --text-muted-light: #64748b;
  --text-muted-dark: #64748b;
  --border-color-light: #e2e8f0;
  --border-color-dark: #1e293b;
  --brand-accent-light: #2563eb;
  --brand-accent-dark: #38bdf8;
  --scrollbar-thumb-light: #94a3b8;
  --scrollbar-thumb-dark: #475569;
  --scrollbar-track-light: #f1f5f9;
  --scrollbar-track-dark: #0f172a;

  /* Source brand accents */
  --color-hn: #ff6600;
  --color-anthropic: #d97757;
  --color-openai: #10a37f;
  --color-grok: #8b5cf6;
  --color-deepseek: #3b82f6;

  /* Default light tokens */
  --bg-canvas: var(--bg-canvas-light);
  --bg-surface: var(--bg-surface-light);
  --bg-elevated: var(--bg-elevated-light);
  --text-primary: var(--text-primary-light);
  --text-secondary: var(--text-secondary-light);
  --text-muted: var(--text-muted-light);
  --border-color: var(--border-color-light);
  --accent-color: var(--brand-accent-light);
  --scrollbar-thumb: var(--scrollbar-thumb-light);
  --scrollbar-track: var(--scrollbar-track-light);

  /* MANDATORY: Fallback for browsers without light-dark support */
  @media (prefers-color-scheme: dark) {
    --bg-canvas: var(--bg-canvas-dark);
    --bg-surface: var(--bg-surface-dark);
    --bg-elevated: var(--bg-elevated-dark);
    --text-primary: var(--text-primary-dark);
    --text-secondary: var(--text-secondary-dark);
    --text-muted: var(--text-muted-dark);
    --border-color: var(--border-color-dark);
    --accent-color: var(--brand-accent-dark);
    --scrollbar-thumb: var(--scrollbar-thumb-dark);
    --scrollbar-track: var(--scrollbar-track-dark);
  }

  /* Use light-dark() when supported */
  @supports (color: light-dark(white, black)) {
    --bg-canvas: light-dark(var(--bg-canvas-light), var(--bg-canvas-dark));
    --bg-surface: light-dark(var(--bg-surface-light), var(--bg-surface-dark));
    --bg-elevated: light-dark(var(--bg-elevated-light), var(--bg-elevated-dark));
    --text-primary: light-dark(var(--text-primary-light), var(--text-primary-dark));
    --text-secondary: light-dark(var(--text-secondary-light), var(--text-secondary-dark));
    --text-muted: light-dark(var(--text-muted-light), var(--text-muted-dark));
    --border-color: light-dark(var(--border-color-light), var(--border-color-dark));
    --accent-color: light-dark(var(--brand-accent-light), var(--brand-accent-dark));
    --scrollbar-thumb: light-dark(var(--scrollbar-thumb-light), var(--scrollbar-thumb-dark));
    --scrollbar-track: light-dark(var(--scrollbar-track-light), var(--scrollbar-track-dark));
  }

  color-scheme: light dark;
  accent-color: var(--accent-color);
  scrollbar-width: thin;
  scrollbar-color: var(--scrollbar-thumb) var(--scrollbar-track);
}

:root.theme-light {
  color-scheme: light;
  --bg-canvas: var(--bg-canvas-light);
  --bg-surface: var(--bg-surface-light);
  --bg-elevated: var(--bg-elevated-light);
  --text-primary: var(--text-primary-light);
  --text-secondary: var(--text-secondary-light);
  --border-color: var(--border-color-light);
  --accent-color: var(--brand-accent-light);
}

:root.theme-dark {
  color-scheme: dark;
  --bg-canvas: var(--bg-canvas-dark);
  --bg-surface: var(--bg-surface-dark);
  --bg-elevated: var(--bg-elevated-dark);
  --text-primary: var(--text-primary-dark);
  --text-secondary: var(--text-secondary-dark);
  --border-color: var(--border-color-dark);
  --accent-color: var(--brand-accent-dark);
}

/* Legacy fallback for WebKit/Blink browsers without scrollbar-color */
@supports not (scrollbar-color: auto) {
  ::-webkit-scrollbar {
    width: 10px;
    height: 10px;
  }
  ::-webkit-scrollbar-thumb {
    background: var(--scrollbar-thumb);
  }
  ::-webkit-scrollbar-track {
    background: var(--scrollbar-track);
  }
}

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

body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Inter, Roboto, sans-serif;
  background-color: var(--bg-canvas);
  color: var(--text-primary);
  line-height: 1.5;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
}

/* Header */
.site-header {
  position: sticky;
  top: 0;
  z-index: 30;
  background-color: var(--bg-surface);
  border-bottom: 1px solid var(--border-color);
}

.header-inner {
  max-width: 1440px;
  margin: 0 auto;
  padding: 0.9rem 1.5rem;
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
}

.brand-group {
  display: flex;
  align-items: center;
  gap: 0.85rem;
}

.brand-logo {
  width: 38px;
  height: 38px;
  border-radius: 10px;
  background: linear-gradient(135deg, #2563eb, #7c3aed);
  display: flex;
  align-items: center;
  justify-content: center;
  box-shadow: 0 4px 12px rgba(37, 99, 235, 0.25);
}

.pulse-dot {
  width: 12px;
  height: 12px;
  border-radius: 50%;
  background: #ffffff;
  box-shadow: 0 0 0 4px rgba(255, 255, 255, 0.3);
}

.brand-title {
  font-size: 1.2rem;
  font-weight: 700;
  letter-spacing: -0.02em;
}

.brand-subtitle {
  font-size: 0.8rem;
  color: var(--text-secondary);
}

.header-actions {
  display: flex;
  align-items: center;
  gap: 0.65rem;
  flex-wrap: wrap;
}

.sync-status {
  display: inline-flex;
  align-items: center;
  gap: 0.45rem;
  font-size: 0.78rem;
  color: var(--text-secondary);
  background: var(--bg-elevated);
  padding: 0.4rem 0.75rem;
  border-radius: 999px;
  border: 1px solid var(--border-color);
}

.sync-indicator {
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background-color: #10b981;
}

.btn-action,
.btn-icon {
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
  font-size: 0.82rem;
  font-weight: 600;
  padding: 0.45rem 0.85rem;
  border-radius: 8px;
  border: 1px solid var(--border-color);
  background: var(--bg-surface);
  color: var(--text-primary);
  cursor: pointer;
  transition: background-color 0.15s ease, border-color 0.15s ease;
}

.btn-action:hover,
.btn-icon:hover {
  background: var(--bg-elevated);
  border-color: var(--accent-color);
}

.btn-action:disabled {
  opacity: 0.6;
  cursor: wait;
}

/* Main & Controls */
.main-container {
  max-width: 1440px;
  width: 100%;
  margin: 0 auto;
  padding: 1.25rem 1.5rem 3rem;
  flex: 1;
}

.controls-bar {
  display: flex;
  flex-direction: column;
  gap: 1rem;
  margin-bottom: 1.5rem;
}

.source-tabs {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
}

.source-tab {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.5rem 0.9rem;
  border-radius: 999px;
  border: 1px solid var(--border-color);
  background: var(--bg-surface);
  color: var(--text-secondary);
  font-size: 0.84rem;
  font-weight: 600;
  cursor: pointer;
  transition: all 0.15s ease;
}

.source-tab:hover {
  color: var(--text-primary);
  background: var(--bg-elevated);
}

.source-tab.active {
  background: var(--text-primary);
  color: var(--bg-surface);
  border-color: var(--text-primary);
}

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

.dot-all { background: linear-gradient(135deg, #ff6600, #3b82f6); }
.dot-hackernews { background: var(--color-hn); }
.dot-anthropic { background: var(--color-anthropic); }
.dot-openai { background: var(--color-openai); }
.dot-grok { background: var(--color-grok); }
.dot-deepseek { background: var(--color-deepseek); }

.tab-count {
  font-size: 0.72rem;
  padding: 0.1rem 0.45rem;
  border-radius: 999px;
  background: rgba(148, 163, 184, 0.2);
  color: inherit;
}

.filter-tools {
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem;
  align-items: center;
  justify-content: space-between;
}

.search-box {
  position: relative;
  flex: 1;
  min-width: 240px;
}

.search-icon {
  position: absolute;
  left: 0.85rem;
  top: 50%;
  transform: translateY(-50%);
  color: var(--text-muted);
  pointer-events: none;
}

#search-input {
  width: 100%;
  padding: 0.58rem 0.9rem 0.58rem 2.4rem;
  border-radius: 8px;
  border: 1px solid var(--border-color);
  background: var(--bg-surface);
  color: var(--text-primary);
  font-size: 0.88rem;
}

#search-input:focus {
  outline: 2px solid var(--accent-color);
  outline-offset: 1px;
}

.view-controls {
  display: flex;
  align-items: center;
  gap: 0.6rem;
}

.select-control {
  padding: 0.52rem 0.8rem;
  border-radius: 8px;
  border: 1px solid var(--border-color);
  background: var(--bg-surface);
  color: var(--text-primary);
  font-size: 0.84rem;
  font-weight: 500;
}

.layout-switch {
  display: inline-flex;
  border: 1px solid var(--border-color);
  border-radius: 8px;
  overflow: hidden;
  background: var(--bg-surface);
}

.layout-btn {
  padding: 0.5rem 0.75rem;
  border: none;
  background: transparent;
  color: var(--text-secondary);
  font-size: 0.8rem;
  font-weight: 600;
  cursor: pointer;
}

.layout-btn.active {
  background: var(--bg-elevated);
  color: var(--text-primary);
}

/* Feed Grid & Radar Columns */
.feed-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(330px, 1fr));
  gap: 1rem;
}

.feed-columns {
  display: grid;
  grid-template-columns: repeat(5, minmax(260px, 1fr));
  gap: 1rem;
  overflow-x: auto;
  padding-bottom: 0.75rem;
}

.radar-column {
  background: var(--bg-elevated);
  border: 1px solid var(--border-color);
  border-radius: 12px;
  padding: 0.85rem;
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
  min-width: 265px;
}

.radar-column-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding-bottom: 0.55rem;
  border-bottom: 1px solid var(--border-color);
  font-weight: 700;
  font-size: 0.92rem;
}

.radar-column-title {
  display: flex;
  align-items: center;
  gap: 0.45rem;
}

/* Size-aware card container (Container Queries) */
.card-container {
  container-type: inline-size;
}

/* Defer rendering strictly for off-screen cards below the fold */
.card-container.deferred-card {
  content-visibility: auto;
  contain-intrinsic-size: auto none auto 210px;
}

/* Default safe stacked card layout */
.article-card {
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  gap: 0.75rem;
  height: 100%;
  padding: 1.05rem;
  border-radius: 10px;
  background: var(--bg-surface);
  border: 1px solid var(--border-color);
  transition: transform 0.12s ease, border-color 0.12s ease, box-shadow 0.12s ease;
  position: relative;
}

.article-card:hover {
  transform: translateY(-2px);
  border-color: var(--accent-color);
  box-shadow: 0 8px 20px rgba(0, 0, 0, 0.08);
}

.card-meta-row {
  display: flex;
  flex-direction: column;
  align-items: flex-start;
  gap: 0.35rem;
  font-size: 0.75rem;
  color: var(--text-muted);
}

/* Fallback using media queries for older browsers */
@media (min-width: 600px) {
  .card-meta-row {
    flex-direction: row;
    align-items: center;
    justify-content: space-between;
  }
}

/* Overwrite with container queries where supported */
@supports (container-type: inline-size) {
  @media (min-width: 600px) {
    .card-meta-row {
      flex-direction: column;
      align-items: flex-start;
    }
  }

  @container (min-width: 300px) {
    .card-meta-row {
      flex-direction: row;
      align-items: center;
      justify-content: space-between;
    }
  }
}

.source-badge {
  display: inline-flex;
  align-items: center;
  gap: 0.35rem;
  font-weight: 700;
  font-size: 0.72rem;
  text-transform: uppercase;
  letter-spacing: 0.04em;
  padding: 0.18rem 0.55rem;
  border-radius: 6px;
}

.badge-hackernews {
  color: #ff6600;
  background: rgba(255, 102, 0, 0.12);
}
.badge-anthropic {
  color: #d97757;
  background: rgba(217, 119, 87, 0.14);
}
.badge-openai {
  color: #10a37f;
  background: rgba(16, 163, 127, 0.14);
}
.badge-grok {
  color: #8b5cf6;
  background: rgba(139, 92, 246, 0.14);
}
.badge-deepseek {
  color: #3b82f6;
  background: rgba(59, 130, 246, 0.14);
}

.card-title-link {
  color: var(--text-primary);
  text-decoration: none;
  font-size: 0.98rem;
  font-weight: 650;
  line-height: 1.38;
  display: block;
}

.card-title-link:hover {
  color: var(--accent-color);
  text-decoration: underline;
}

.card-summary {
  font-size: 0.83rem;
  color: var(--text-secondary);
  line-height: 1.48;
  display: -webkit-box;
  -webkit-line-clamp: 3;
  -webkit-box-orient: vertical;
  overflow: hidden;
}

.card-footer {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 0.5rem;
  padding-top: 0.55rem;
  border-top: 1px solid var(--border-color);
  font-size: 0.75rem;
  color: var(--text-muted);
}

.card-author {
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
  max-width: 160px;
}

.card-links {
  display: inline-flex;
  align-items: center;
  gap: 0.55rem;
}

.hn-discuss-link {
  color: var(--text-secondary);
  text-decoration: none;
  font-weight: 600;
  padding: 0.15rem 0.45rem;
  border-radius: 4px;
  background: var(--bg-elevated);
}

.hn-discuss-link:hover {
  color: var(--color-hn);
}

.open-link-pill {
  color: var(--accent-color);
  text-decoration: none;
  font-weight: 600;
  display: inline-flex;
  align-items: center;
  gap: 0.2rem;
}

/* Loading & Empty States */
.loading-state,
.empty-state {
  text-align: center;
  padding: 4rem 1rem;
  color: var(--text-secondary);
}

.spinner {
  width: 32px;
  height: 32px;
  border: 3px solid var(--border-color);
  border-top-color: var(--accent-color);
  border-radius: 50%;
  margin: 0 auto 1rem;
  animation: spin 0.8s linear infinite;
}

@keyframes spin {
  to { transform: rotate(360deg); }
}

/* Footer */
.site-footer {
  border-top: 1px solid var(--border-color);
  background: var(--bg-surface);
  padding: 1rem 1.5rem;
  font-size: 0.8rem;
  color: var(--text-secondary);
}

.footer-inner {
  max-width: 1440px;
  margin: 0 auto;
  display: flex;
  flex-wrap: wrap;
  justify-content: space-between;
  gap: 0.5rem;
}