/* === SaoAI News — Professional UI v3 === */
:root {
  --primary: #2563eb;
  --primary-dark: #1d4ed8;
  --secondary: #7c3aed;
  --accent: #f59e0b;
  --bg: #f8fafc;
  --surface: #ffffff;
  --text: #0f172a;
  --text-muted: #475569;
  --text-light: #94a3b8;
  --border: #e2e8f0;
  --border-light: #f1f5f9;
  --shadow: 0 1px 2px rgba(0,0,0,0.04);
  --shadow-card: 0 1px 3px rgba(0,0,0,0.06), 0 1px 2px rgba(0,0,0,0.03);
  --shadow-hover: 0 8px 24px rgba(0,0,0,0.08), 0 2px 8px rgba(0,0,0,0.04);
  --radius: 10px;
  --radius-lg: 14px;
}

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

body {
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'Inter', system-ui, sans-serif;
  background: var(--bg);
  color: var(--text);
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
}

/* ===== HEADER ===== */
header {
  background: rgba(255,255,255,0.88);
  backdrop-filter: blur(16px) saturate(180%);
  -webkit-backdrop-filter: blur(16px) saturate(180%);
  border-bottom: 1px solid var(--border);
  position: sticky;
  top: 0;
  z-index: 100;
}
.header-inner {
  max-width: 1240px;
  margin: 0 auto;
  padding: 16px 24px;
  display: flex;
  justify-content: space-between;
  align-items: center;
}
.logo {
  display: flex;
  align-items: center;
  gap: 14px;
  text-decoration: none;
  color: var(--text);
}
.logo-icon {
  height: 52px;
  width: auto;
  display: block;
  flex-shrink: 0;
}
.logo-text {
  display: flex;
  flex-direction: column;
  gap: 0;
  line-height: 1.15;
}
.logo-text .brand {
  font-size: 1.65rem;
  font-weight: 800;
  letter-spacing: -0.03em;
  color: var(--text);
}
.logo-text .tagline {
  font-size: 0.78rem;
  font-weight: 400;
  color: var(--text-muted);
  letter-spacing: 0.01em;
}

.header-nav {
  display: flex;
  align-items: center;
  gap: 14px;
}
.nav-stat {
  font-size: 0.78rem;
  font-weight: 600;
  color: var(--text-muted);
  background: var(--border-light);
  padding: 6px 15px;
  border-radius: 100px;
}
.lang-toggle {
  display: flex;
  gap: 3px;
  background: var(--border-light);
  border-radius: 10px;
  padding: 3px;
}
.lang-toggle button {
  padding: 6px 14px;
  border: none;
  background: transparent;
  color: var(--text-muted);
  border-radius: 8px;
  cursor: pointer;
  font-size: 0.8rem;
  font-weight: 600;
  transition: all 0.2s;
}
.lang-toggle button.active {
  background: var(--surface);
  color: var(--primary);
  box-shadow: 0 1px 3px rgba(0,0,0,0.06);
}

/* ===== HERO ===== */
.hero {
  text-align: center;
  padding: 52px 24px 44px;
  background: linear-gradient(160deg, #eff6ff 0%, #f5f3ff 40%, #fefce8 100%);
  border-bottom: 1px solid var(--border);
}
.hero-badge {
  display: inline-block;
  padding: 4px 14px;
  background: rgba(37,99,235,0.08);
  color: var(--primary);
  border-radius: 100px;
  font-size: 0.78rem;
  font-weight: 700;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  margin-bottom: 16px;
}
.hero h1 {
  font-size: 2.2rem;
  font-weight: 800;
  letter-spacing: -0.03em;
  background: linear-gradient(135deg, var(--primary), var(--secondary));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  margin-bottom: 8px;
  line-height: 1.25;
}
.hero p {
  color: var(--text-muted);
  font-size: 1rem;
}

/* ===== FILTERS ===== */
.filters {
  max-width: 1240px;
  margin: 0 auto;
  padding: 20px 24px 8px;
}
.filter-section {
  margin-bottom: 14px;
}
.filter-section-title {
  font-size: 0.7rem;
  font-weight: 800;
  text-transform: uppercase;
  letter-spacing: 0.1em;
  color: var(--text-light);
  margin-bottom: 8px;
}
.filter-row {
  display: flex;
  flex-wrap: wrap;
  gap: 7px;
}
.filter-chip {
  padding: 7px 16px;
  border: 1px solid var(--border);
  background: var(--surface);
  color: var(--text-muted);
  border-radius: 100px;
  cursor: pointer;
  font-size: 0.8rem;
  font-weight: 500;
  transition: all 0.2s ease;
  white-space: nowrap;
  user-select: none;
}
.filter-chip:hover {
  border-color: var(--primary);
  color: var(--primary);
  background: #f0f7ff;
}
.filter-chip.active {
  background: var(--primary);
  border-color: var(--primary);
  color: #fff;
  box-shadow: 0 2px 8px rgba(37,99,235,0.2);
}
.filter-chip .count {
  font-size: 0.7rem;
  opacity: 0.55;
  margin-left: 2px;
}
.filter-chip.active .count { opacity: 0.85; }

/* Category chips (primary) */
.cat-chip:hover { border-color: var(--primary); color: var(--primary); background: #eff6ff; }
.cat-chip.active { background: var(--primary); border-color: var(--primary); color: #fff; box-shadow: 0 2px 8px rgba(37,99,235,0.2); }

/* Source chips (secondary) */
.src-chip:hover { border-color: var(--secondary); color: var(--secondary); background: #f5f3ff; }
.src-chip.active { background: var(--secondary); border-color: var(--secondary); color: #fff; box-shadow: 0 2px 8px rgba(124,58,237,0.2); }

/* Separator */
.filter-sep {
  display: inline-flex;
  align-items: center;
  color: var(--border);
  font-weight: 300;
  font-size: 1.2rem;
  margin: 0 4px;
  user-select: none;
}

.source-toggle {
  display: inline-flex;
  align-items: center;
  gap: 4px;
  padding: 7px 16px;
  border: 1px dashed var(--border);
  background: transparent;
  color: var(--text-light);
  border-radius: 100px;
  cursor: pointer;
  font-size: 0.8rem;
  font-weight: 500;
  transition: all 0.2s;
}
.source-toggle:hover { border-color: var(--secondary); color: var(--secondary); }
.source-more { display: none; }
.source-more.show { display: contents; }

/* ===== ARTICLES ===== */
.articles {
  max-width: 1240px;
  margin: 0 auto;
  padding: 20px 24px 48px;
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(370px, 1fr));
  gap: 22px;
}

.loading, .empty, .error {
  grid-column: 1 / -1;
  text-align: center;
  padding: 80px 24px;
  color: var(--text-muted);
}

/* ===== CARD ===== */
.card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  overflow: hidden;
  cursor: pointer;
  box-shadow: var(--shadow-card);
  transition: all 0.25s ease;
  display: flex;
  flex-direction: column;
}
.card:hover {
  transform: translateY(-2px);
  box-shadow: var(--shadow-hover);
  border-color: #cbd5e1;
}
.card-img {
  width: 100%;
  height: 190px;
  overflow: hidden;
  background: linear-gradient(135deg, #f0f4ff, #f5f0ff);
}
.card-img img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  transition: transform 0.4s ease;
}
.card:hover .card-img img { transform: scale(1.03); }
.card-img-placeholder {
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 2.5rem;
  opacity: 0.4;
}
.card-body {
  padding: 16px 18px 14px;
  flex: 1;
  display: flex;
  flex-direction: column;
}
.card-top {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 6px;
  gap: 8px;
}
.card-source {
  font-size: 0.68rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  color: var(--primary);
}
.card-category {
  font-size: 0.65rem;
  font-weight: 600;
  padding: 3px 10px;
  border-radius: 100px;
  background: linear-gradient(135deg, #eff6ff, #f5f3ff);
  color: var(--secondary);
  white-space: nowrap;
}
.card-body h3 {
  font-size: 1rem;
  font-weight: 700;
  line-height: 1.45;
  margin-bottom: 6px;
  color: var(--text);
  display: -webkit-box;
  -webkit-line-clamp: 3;
  -webkit-box-orient: vertical;
  overflow: hidden;
}
.card-summary {
  font-size: 0.83rem;
  color: var(--text-muted);
  line-height: 1.55;
  display: -webkit-box;
  -webkit-line-clamp: 3;
  -webkit-box-orient: vertical;
  overflow: hidden;
  flex: 1;
  margin-bottom: 12px;
}
.card-meta {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding-top: 12px;
  border-top: 1px solid var(--border-light);
  font-size: 0.73rem;
  color: var(--text-light);
}
.badge-vi {
  font-size: 0.65rem;
  font-weight: 600;
  padding: 3px 9px;
  border-radius: 100px;
  background: #ecfdf5;
  color: #059669;
}

/* ===== DETAIL ===== */
.detail {
  grid-column: 1 / -1;
  max-width: 760px;
  margin: 0 auto;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: 32px 36px;
  box-shadow: var(--shadow-card);
}
.detail-back {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 8px 16px;
  border: 1px solid var(--border);
  background: var(--surface);
  color: var(--text-muted);
  border-radius: 100px;
  cursor: pointer;
  font-size: 0.83rem;
  font-weight: 500;
  margin-bottom: 24px;
  transition: all 0.2s;
}
.detail-back:hover { border-color: var(--primary); color: var(--primary); }
.detail-meta { display: flex; gap: 10px; align-items: center; margin-bottom: 12px; }
.detail h2 {
  font-size: 1.55rem;
  font-weight: 800;
  margin-bottom: 8px;
  line-height: 1.4;
  letter-spacing: -0.02em;
}
.detail-date { font-size: 0.85rem; color: var(--text-muted); margin-bottom: 24px; }
.detail-content {
  font-size: 0.98rem;
  line-height: 1.85;
  color: var(--text);
}
.detail-link {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  margin-top: 24px;
  padding: 10px 22px;
  background: var(--primary);
  color: #fff;
  text-decoration: none;
  border-radius: 100px;
  font-size: 0.85rem;
  font-weight: 600;
  transition: all 0.2s;
}
.detail-link:hover { background: var(--primary-dark); }
.detail-lang {
  display: flex;
  gap: 8px;
  margin-top: 28px;
  padding-top: 22px;
  border-top: 1px solid var(--border);
}
.detail-lang button {
  padding: 7px 18px;
  border: 1px solid var(--border);
  background: var(--surface);
  color: var(--text-muted);
  border-radius: 100px;
  cursor: pointer;
  font-size: 0.83rem;
  font-weight: 500;
  transition: all 0.2s;
}
.detail-lang button.active { background: var(--primary); border-color: var(--primary); color: #fff; }

/* ===== PAGINATION ===== */
.pagination {
  display: flex;
  justify-content: center;
  gap: 5px;
  padding: 0 24px 44px;
}
.page-btn {
  min-width: 38px;
  height: 38px;
  padding: 0 12px;
  border: 1px solid var(--border);
  background: var(--surface);
  color: var(--text-muted);
  border-radius: 9px;
  cursor: pointer;
  font-size: 0.83rem;
  font-weight: 600;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  transition: all 0.2s;
}
.page-btn:hover { border-color: var(--primary); color: var(--primary); }
.page-btn.active {
  background: var(--primary);
  border-color: var(--primary);
  color: #fff;
  box-shadow: 0 2px 6px rgba(37,99,235,0.2);
}
.page-dots {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-width: 38px;
  height: 38px;
  color: var(--text-light);
  font-weight: 700;
  font-size: 0.85rem;
}

/* ===== SPINNER ===== */
.spinner {
  width: 32px; height: 32px;
  border: 3px solid var(--border);
  border-top-color: var(--primary);
  border-radius: 50%;
  animation: spin 0.7s linear infinite;
  margin: 0 auto 12px;
}
@keyframes spin { to { transform: rotate(360deg); } }

/* ===== FOOTER ===== */
footer {
  text-align: center;
  padding: 24px;
  color: var(--text-light);
  font-size: 0.78rem;
  border-top: 1px solid var(--border);
  background: var(--surface);
}

/* ===== MOBILE ===== */
@media (max-width: 640px) {
  .header-inner { padding: 10px 16px; }
  .logo-icon { height: 40px; }
  .logo-text .brand { font-size: 1.3rem; }
  .logo-text .tagline { font-size: 0.7rem; }
  .hero { padding: 36px 16px 28px; }
  .hero h1 { font-size: 1.45rem; }
  .articles { grid-template-columns: 1fr; padding: 16px; gap: 16px; }
  .filters { padding: 14px 16px 6px; }
  .detail { padding: 22px 18px; }
}

/* Beautiful placeholders per category */
.card-img-placeholder {
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 3rem;
}
.card-img-placeholder.cat-AI { background: linear-gradient(135deg, #dbeafe, #ede9fe); }
.card-img-placeholder.cat-Robotics { background: linear-gradient(135deg, #c7d2fe, #bae6fd); }
.card-img-placeholder.cat-Research { background: linear-gradient(135deg, #e0f2fe, #e0e7ff); }
.card-img-placeholder.cat-Investment { background: linear-gradient(135deg, #fef3c7, #fce7f3); }
.card-img-placeholder.cat-Corporate { background: linear-gradient(135deg, #dcfce7, #dbeafe); }
.card-img-placeholder.cat-Infrastructure { background: linear-gradient(135deg, #fee2e2, #fed7aa); }
.card-img-placeholder.cat-Startups { background: linear-gradient(135deg, #d1fae5, #cffafe); }
.card-img-placeholder.cat-Policy { background: linear-gradient(135deg, #fce7f3, #ede9fe); }
.card-img-placeholder.cat-Models { background: linear-gradient(135deg, #e0e7ff, #fae8ff); }
.card-img-placeholder.cat-Competition { background: linear-gradient(135deg, #fee2e2, #fef2f2); }
.card-img-placeholder.cat-Partnerships { background: linear-gradient(135deg, #dbeafe, #d1fae5); }
.card-img-placeholder.default { background: linear-gradient(135deg, #f1f5f9, #e2e8f0); }