/* Happy AI 科技日报 - 站点样式 */
:root {
  --bg: #0b1120;
  --bg-soft: #121a2e;
  --card: #161f38;
  --card-hover: #1c2745;
  --border: #26314f;
  --text: #e6ebf5;
  --text-dim: #93a1c0;
  --accent: #6ee7f5;
  --accent2: #a78bfa;
  --accent3: #f472b6;
  --tag-model: #6ee7f5;
  --tag-product: #a78bfa;
  --tag-science: #34d399;
  --tag-chip: #fbbf24;
  --tag-agent: #f472b6;
  --tag-safety: #f87171;
  --tag-industry: #60a5fa;
  --radius: 14px;
}

* { box-sizing: border-box; }

body {
  margin: 0;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Microsoft YaHei", Helvetica, Arial, sans-serif;
  background: radial-gradient(circle at 20% -10%, #1c2b52 0%, var(--bg) 45%), var(--bg);
  color: var(--text);
  line-height: 1.6;
  min-height: 100vh;
}

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

.container {
  max-width: 1080px;
  margin: 0 auto;
  padding: 0 20px;
}

/* 顶部导航 */
header.site-header {
  position: sticky;
  top: 0;
  z-index: 50;
  background: rgba(11, 17, 32, 0.85);
  backdrop-filter: blur(10px);
  border-bottom: 1px solid var(--border);
}

.nav-bar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 14px 20px;
  max-width: 1080px;
  margin: 0 auto;
}

.brand {
  display: flex;
  align-items: center;
  gap: 10px;
  font-weight: 700;
  font-size: 1.15rem;
}

.brand .dot {
  width: 10px;
  height: 10px;
  border-radius: 50%;
  background: linear-gradient(135deg, var(--accent), var(--accent2));
  box-shadow: 0 0 10px var(--accent);
}

.nav-links {
  display: flex;
  gap: 22px;
  font-size: 0.94rem;
  color: var(--text-dim);
}

.nav-links a:hover, .nav-links a.active { color: var(--accent); }

/* Hero */
.hero {
  padding: 56px 0 32px;
  text-align: center;
}

.hero h1 {
  font-size: 2.1rem;
  margin: 0 0 10px;
  background: linear-gradient(120deg, var(--accent), var(--accent2), var(--accent3));
  -webkit-background-clip: text;
  background-clip: text;
  -webkit-text-fill-color: transparent;
  font-weight: 800;
}

.hero p {
  color: var(--text-dim);
  font-size: 1.02rem;
  max-width: 640px;
  margin: 0 auto;
}

.hero .meta-row {
  margin-top: 18px;
  display: flex;
  justify-content: center;
  gap: 28px;
  color: var(--text-dim);
  font-size: 0.88rem;
}

.hero .meta-row b { color: var(--accent); font-size: 1.1rem; }

/* Section 标题 */
.section-title {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  margin: 40px 0 18px;
}

.section-title h2 {
  font-size: 1.3rem;
  margin: 0;
  display: flex;
  align-items: center;
  gap: 8px;
}

.section-title h2::before {
  content: "";
  width: 4px;
  height: 18px;
  border-radius: 2px;
  background: linear-gradient(180deg, var(--accent), var(--accent2));
  display: inline-block;
}

.section-title .more {
  font-size: 0.86rem;
  color: var(--text-dim);
}
.section-title .more:hover { color: var(--accent); }

/* 卡片 */
.card-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
  gap: 16px;
}

.news-card {
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 18px;
  display: flex;
  flex-direction: column;
  gap: 10px;
  transition: transform .15s ease, border-color .15s ease, background .15s ease;
}

.news-card:hover {
  transform: translateY(-3px);
  border-color: var(--accent);
  background: var(--card-hover);
}

.tag-row { display: flex; gap: 8px; align-items: center; flex-wrap: wrap; }

.tag {
  font-size: 0.72rem;
  padding: 3px 9px;
  border-radius: 999px;
  border: 1px solid currentColor;
  opacity: 0.9;
}

.tag.model { color: var(--tag-model); }
.tag.product { color: var(--tag-product); }
.tag.science { color: var(--tag-science); }
.tag.chip { color: var(--tag-chip); }
.tag.agent { color: var(--tag-agent); }
.tag.safety { color: var(--tag-safety); }
.tag.industry { color: var(--tag-industry); }

.news-card h3 {
  margin: 0;
  font-size: 1.04rem;
  line-height: 1.4;
}

.news-card p.summary {
  margin: 0;
  color: var(--text-dim);
  font-size: 0.9rem;
  flex-grow: 1;
  display: -webkit-box;
  -webkit-line-clamp: 3;
  -webkit-box-orient: vertical;
  overflow: hidden;
}

.card-footer {
  display: flex;
  justify-content: space-between;
  align-items: center;
  font-size: 0.78rem;
  color: var(--text-dim);
  border-top: 1px solid var(--border);
  padding-top: 10px;
}

.card-footer .source { color: var(--accent); }

/* 今日焦点大卡 */
.featured {
  background: linear-gradient(135deg, rgba(110,231,245,0.08), rgba(167,139,250,0.08));
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 24px;
  margin-bottom: 10px;
}

.featured .tag-row { margin-bottom: 10px; }
.featured h3 { font-size: 1.3rem; margin: 0 0 8px; }
.featured p { color: var(--text-dim); margin: 0 0 10px; }

/* 按天分组（周报/归档） */
.day-group { margin-bottom: 30px; }
.day-group .day-title {
  font-size: 1rem;
  color: var(--accent);
  margin-bottom: 12px;
  padding-bottom: 6px;
  border-bottom: 1px dashed var(--border);
}

/* 归档索引列表 */
.archive-list { list-style: none; padding: 0; margin: 0; }
.archive-list li {
  display: flex;
  justify-content: space-between;
  padding: 14px 4px;
  border-bottom: 1px solid var(--border);
}
.archive-list li:hover { background: rgba(255,255,255,0.02); }
.archive-list .date { color: var(--accent); font-weight: 600; }
.archive-list .count { color: var(--text-dim); font-size: 0.86rem; }

/* 页脚 */
footer.site-footer {
  margin-top: 60px;
  border-top: 1px solid var(--border);
  padding: 28px 0 40px;
  text-align: center;
  color: var(--text-dim);
  font-size: 0.84rem;
}

.empty-state {
  text-align: center;
  color: var(--text-dim);
  padding: 60px 20px;
}

@media (max-width: 640px) {
  .nav-links { gap: 14px; font-size: 0.86rem; }
  .hero h1 { font-size: 1.6rem; }
  .hero .meta-row { gap: 16px; flex-wrap: wrap; }
}