:root {
  --bg: #09111f;
  --panel: rgba(11, 22, 40, 0.82);
  --panel-border: rgba(255, 255, 255, 0.08);
  --panel-soft: rgba(255, 255, 255, 0.05);
  --text: #eef4ff;
  --text-soft: #9fb1d2;
  --accent: #7aa2ff;
  --accent-strong: #8b5cf6;
  --shadow: 0 24px 60px rgba(0, 0, 0, 0.35);
  --radius-xl: 28px;
  --radius-lg: 20px;
  --radius-md: 14px;
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  min-height: 100vh;
  color: var(--text);
  font-family: "Microsoft YaHei", "PingFang SC", sans-serif;
  background:
    radial-gradient(circle at top left, rgba(122, 162, 255, 0.22), transparent 28%),
    radial-gradient(circle at top right, rgba(139, 92, 246, 0.18), transparent 24%),
    linear-gradient(180deg, #0a1426 0%, #08101d 100%);
}

a {
  color: inherit;
  text-decoration: none;
}

.page-shell {
  width: min(1380px, calc(100% - 32px));
  margin: 0 auto;
  padding: 28px 0 40px;
}

.hero {
  display: grid;
  grid-template-columns: minmax(0, 1.25fr) minmax(300px, 420px);
  gap: 24px;
  align-items: stretch;
  margin-bottom: 24px;
}

.hero__content,
.hero__panel-card,
.sidebar,
.content-panel {
  border: 1px solid var(--panel-border);
  background: var(--panel);
  backdrop-filter: blur(16px);
  box-shadow: var(--shadow);
}

.hero__content {
  border-radius: var(--radius-xl);
  padding: 32px;
}

.hero__eyebrow,
.toolbar__eyebrow,
.sidebar__label,
.stat-card__label,
.hero__panel-title {
  margin: 0;
  color: var(--text-soft);
  font-size: 13px;
  letter-spacing: 0.16em;
  text-transform: uppercase;
}

.hero h1 {
  margin: 12px 0;
  font-size: clamp(2rem, 4vw, 3.2rem);
  line-height: 1.1;
}

.hero__desc {
  max-width: 760px;
  margin: 0;
  color: #d4def2;
  font-size: 16px;
  line-height: 1.8;
}

.hero__stats {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 14px;
  margin-top: 28px;
}

.stat-card {
  padding: 18px;
  border: 1px solid var(--panel-border);
  border-radius: var(--radius-lg);
  background: var(--panel-soft);
}

.stat-card strong {
  display: block;
  margin-top: 10px;
  font-size: 28px;
}

.hero__panel {
  display: flex;
}

.hero__panel-card {
  width: 100%;
  border-radius: var(--radius-xl);
  padding: 28px;
}

.structure-list {
  margin: 18px 0 0;
  padding: 0;
  list-style: none;
  display: grid;
  gap: 14px;
}

.structure-list li {
  padding: 14px 16px;
  border-radius: var(--radius-md);
  background: rgba(255, 255, 255, 0.04);
  border: 1px solid rgba(255, 255, 255, 0.06);
  color: #dce7ff;
}

.app-shell {
  display: grid;
  grid-template-columns: 280px minmax(0, 1fr);
  gap: 24px;
}

.sidebar,
.content-panel {
  border-radius: var(--radius-xl);
}

.sidebar {
  padding: 20px;
}

.sidebar__section + .sidebar__section {
  margin-top: 24px;
}

.channel-tabs,
.category-tabs {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  margin-top: 14px;
}

.channel-tab,
.category-tab {
  border: 1px solid rgba(255, 255, 255, 0.08);
  background: rgba(255, 255, 255, 0.04);
  color: var(--text);
  border-radius: 999px;
  cursor: pointer;
  transition: 0.2s ease;
}

.channel-tab {
  width: 100%;
  padding: 12px 16px;
  text-align: left;
  font-size: 15px;
}

.category-tab {
  padding: 10px 14px;
  font-size: 14px;
}

.channel-tab:hover,
.category-tab:hover,
.channel-tab.is-active,
.category-tab.is-active {
  border-color: rgba(122, 162, 255, 0.4);
  background: linear-gradient(135deg, rgba(122, 162, 255, 0.28), rgba(139, 92, 246, 0.2));
  transform: translateY(-1px);
}

.tips-list {
  margin: 14px 0 0;
  padding-left: 18px;
  color: #d1dcf5;
  line-height: 1.9;
}

.content-panel {
  padding: 24px;
}

.toolbar {
  display: flex;
  justify-content: space-between;
  align-items: end;
  gap: 16px;
  margin-bottom: 24px;
}

.toolbar h2 {
  margin: 10px 0 0;
  font-size: clamp(1.5rem, 3vw, 2.2rem);
}

.toolbar__meta {
  color: var(--text-soft);
  font-size: 14px;
}

.cover-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(170px, 1fr));
  gap: 18px;
}

.cover-card {
  position: relative;
  overflow: hidden;
  border-radius: 22px;
  aspect-ratio: 3 / 4.2;
  background: rgba(255, 255, 255, 0.04);
  border: 1px solid rgba(255, 255, 255, 0.08);
  box-shadow: 0 16px 32px rgba(0, 0, 0, 0.22);
  transition: transform 0.22s ease, box-shadow 0.22s ease;
}

.cover-card img {
  width: 100%;
  height: 100%;
  display: block;
  object-fit: cover;
}

.cover-card__mask {
  position: absolute;
  inset: auto 0 0 0;
  padding: 16px;
  display: flex;
  justify-content: space-between;
  align-items: center;
  color: #fff;
  background: linear-gradient(180deg, transparent, rgba(0, 0, 0, 0.76));
  opacity: 0;
  transition: opacity 0.22s ease;
}

.cover-card__badge {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-width: 42px;
  height: 42px;
  padding: 0 10px;
  border-radius: 999px;
  border: 1px solid rgba(255, 255, 255, 0.18);
  background: rgba(255, 255, 255, 0.12);
  font-size: 13px;
}

.cover-card__action {
  font-size: 14px;
  letter-spacing: 0.08em;
}

.cover-card:hover {
  transform: translateY(-6px);
  box-shadow: 0 24px 40px rgba(0, 0, 0, 0.35);
}

.cover-card:hover .cover-card__mask {
  opacity: 1;
}

.empty-state {
  padding: 54px 20px;
  border-radius: var(--radius-lg);
  border: 1px dashed rgba(255, 255, 255, 0.14);
  text-align: center;
  color: var(--text-soft);
}

@media (max-width: 1040px) {
  .hero,
  .app-shell {
    grid-template-columns: 1fr;
  }

  .channel-tab {
    width: auto;
  }
}

@media (max-width: 720px) {
  .page-shell {
    width: min(100% - 20px, 100%);
    padding-top: 16px;
  }

  .hero__content,
  .hero__panel-card,
  .sidebar,
  .content-panel {
    padding: 20px;
  }

  .hero__stats {
    grid-template-columns: 1fr;
  }

  .toolbar {
    flex-direction: column;
    align-items: start;
  }

  .cover-grid {
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 14px;
  }
}