/* OptiV 文章合集页 · OPV-30 / OPV-50 共用 */
:root {
  --primary: #6cbbf2;
  --primary-dark: #0c5c9c;
  --dark: #0a0f1c;
  --dark-card: rgba(15, 23, 41, 0.85);
  --text: #b8d4f0;
  --text-muted: #94a3b8;
  --border: rgba(108, 187, 242, 0.14);
  --glow: rgba(108, 187, 242, 0.22);
}

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

body {
  font-family: 'Segoe UI', 'PingFang SC', 'Microsoft YaHei', sans-serif;
  background: var(--dark);
  color: var(--text);
  line-height: 1.6;
  min-height: 100vh;
}

body::before {
  content: '';
  position: fixed;
  inset: 0;
  background:
    radial-gradient(ellipse 80% 50% at 50% -10%, rgba(108, 187, 242, 0.12), transparent),
    radial-gradient(circle at 90% 80%, rgba(12, 92, 156, 0.08), transparent);
  pointer-events: none;
  z-index: 0;
}

.hub-header {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 1000;
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0.85rem 6%;
  background: rgba(10, 15, 28, 0.92);
  backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border);
}

.hub-brand {
  display: flex;
  align-items: center;
  gap: 10px;
  text-decoration: none;
  color: #fff;
  font-weight: 600;
  font-size: 15px;
}

.hub-brand img {
  width: 28px;
  height: 28px;
  border-radius: 6px;
}

.hub-nav {
  display: flex;
  align-items: center;
  gap: 6px;
  flex-wrap: wrap;
}

.hub-nav a {
  color: var(--text-muted);
  text-decoration: none;
  font-size: 13px;
  padding: 6px 12px;
  border-radius: 8px;
  transition: 0.2s;
}

.hub-nav a:hover,
.hub-nav a.active {
  color: var(--primary);
  background: rgba(108, 187, 242, 0.1);
}

.hub-hero {
  position: relative;
  z-index: 1;
  padding: 110px 6% 36px;
  text-align: center;
}

.hub-badge {
  display: inline-block;
  padding: 5px 14px;
  margin-bottom: 16px;
  font-size: 11px;
  font-weight: 600;
  letter-spacing: 2px;
  text-transform: uppercase;
  color: var(--primary);
  background: rgba(108, 187, 242, 0.1);
  border: 1px solid rgba(108, 187, 242, 0.25);
  border-radius: 20px;
}

.hub-hero h1 {
  font-size: clamp(1.6rem, 4vw, 2.25rem);
  font-weight: 700;
  color: #fff;
  letter-spacing: 0.5px;
  margin-bottom: 18px;
  line-height: 1.3;
}

.hub-hero h1 span {
  background: linear-gradient(135deg, #fff 0%, var(--primary) 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.hub-stats {
  display: flex;
  justify-content: center;
  gap: 12px;
  flex-wrap: wrap;
}

.hub-stat {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 8px 16px;
  font-size: 13px;
  color: var(--text);
  background: var(--dark-card);
  border: 1px solid var(--border);
  border-radius: 10px;
}

.hub-stat i {
  color: var(--primary);
  font-size: 12px;
}

.hub-toolbar {
  position: relative;
  z-index: 1;
  max-width: 720px;
  margin: 0 auto 28px;
  padding: 0 6%;
}

.hub-search {
  position: relative;
}

.hub-search i {
  position: absolute;
  left: 18px;
  top: 50%;
  transform: translateY(-50%);
  color: var(--text-muted);
  font-size: 14px;
}

.hub-search input {
  width: 100%;
  padding: 14px 18px 14px 44px;
  border-radius: 14px;
  border: 1px solid var(--border);
  background: rgba(255, 255, 255, 0.04);
  color: #fff;
  font-size: 14px;
  outline: none;
  transition: 0.2s;
}

.hub-search input:focus {
  border-color: var(--primary);
  box-shadow: 0 0 0 3px rgba(108, 187, 242, 0.12);
}

.hub-search input::placeholder {
  color: #64748b;
}

.hub-filters {
  position: relative;
  z-index: 1;
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  justify-content: center;
  padding: 0 6% 28px;
  max-width: 1200px;
  margin: 0 auto;
}

.filter-btn {
  padding: 7px 14px;
  border: 1px solid var(--border);
  background: rgba(255, 255, 255, 0.03);
  color: var(--text-muted);
  border-radius: 20px;
  cursor: pointer;
  font-size: 12px;
  transition: 0.22s;
  white-space: nowrap;
}

.filter-btn:hover {
  color: var(--primary);
  border-color: rgba(108, 187, 242, 0.35);
}

.filter-btn.active {
  background: linear-gradient(135deg, var(--primary), var(--primary-dark));
  color: #fff;
  border-color: transparent;
  box-shadow: 0 4px 16px var(--glow);
}

.hub-grid {
  position: relative;
  z-index: 1;
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(320px, 1fr));
  gap: 18px;
  padding: 0 6% 64px;
  max-width: 1400px;
  margin: 0 auto;
}

.hub-card {
  position: relative;
  background: linear-gradient(145deg, rgba(255, 255, 255, 0.05), rgba(255, 255, 255, 0.02));
  border: 1px solid var(--border);
  border-radius: 16px;
  padding: 22px;
  transition: 0.28s;
}

.hub-card:hover {
  border-color: rgba(108, 187, 242, 0.35);
  transform: translateY(-3px);
  box-shadow: 0 10px 32px rgba(0, 0, 0, 0.22), 0 0 20px var(--glow);
}

.hub-card-top {
  display: flex;
  justify-content: space-between;
  align-items: flex-start;
  gap: 10px;
  margin-bottom: 10px;
}

.hub-card .series {
  font-size: 11px;
  color: var(--primary);
  letter-spacing: 0.5px;
  line-height: 1.4;
  flex: 1;
}

.hub-num {
  flex-shrink: 0;
  font-size: 11px;
  font-weight: 700;
  color: var(--primary);
  background: rgba(108, 187, 242, 0.12);
  padding: 3px 8px;
  border-radius: 6px;
}

.hub-card h2 {
  font-size: 15px;
  font-weight: 600;
  color: #fff;
  margin-bottom: 10px;
  line-height: 1.5;
}

.hub-card h2 a {
  color: inherit;
  text-decoration: none;
}

.hub-card h2 a:hover {
  color: var(--primary);
}

.hub-card p {
  font-size: 12px;
  color: var(--text-muted);
  margin-bottom: 14px;
  line-height: 1.65;
  display: -webkit-box;
  -webkit-line-clamp: 3;
  -webkit-box-orient: vertical;
  overflow: hidden;
}

.hub-card .tags span {
  display: inline-block;
  font-size: 10px;
  padding: 3px 8px;
  margin: 2px 4px 2px 0;
  background: rgba(108, 187, 242, 0.08);
  border: 1px solid rgba(108, 187, 242, 0.15);
  border-radius: 8px;
  color: var(--primary);
}

.hub-empty {
  grid-column: 1 / -1;
  text-align: center;
  padding: 48px 20px;
  color: var(--text-muted);
}

.hub-empty i {
  font-size: 2rem;
  color: var(--primary);
  opacity: 0.5;
  margin-bottom: 12px;
}

.hub-footer {
  position: relative;
  z-index: 1;
  text-align: center;
  padding: 28px 6% 36px;
  border-top: 1px solid var(--border);
  font-size: 12px;
  color: #64748b;
}

.hub-footer a {
  color: var(--primary);
  text-decoration: none;
}

.hub-footer a:hover {
  text-decoration: underline;
}

@media (max-width: 640px) {
  .hub-header { padding: 0.75rem 4%; }
  .hub-nav a { padding: 5px 8px; font-size: 12px; }
  .hub-grid { grid-template-columns: 1fr; padding: 0 4% 48px; }
  .hub-filters { padding: 0 4% 20px; }
}