/* 科技日报 - 主样式 */
:root {
  --bg: #0f1117;
  --bg2: #1a1d27;
  --bg3: #22263a;
  --accent: #4f8ef7;
  --accent2: #7c3aed;
  --text: #e2e8f0;
  --text2: #94a3b8;
  --border: #2d3748;
  --card-bg: #1e2235;
  --radius: 12px;
  --shadow: 0 4px 24px rgba(0,0,0,0.4);
}

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

body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC",
    "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
  background: var(--bg);
  color: var(--text);
  line-height: 1.7;
  min-height: 100vh;
}

/* ── Header ── */
.site-header {
  background: linear-gradient(135deg, #1a1d27 0%, #0f1117 100%);
  border-bottom: 1px solid var(--border);
  padding: 2rem 0 1.5rem;
}
.header-inner {
  max-width: 1100px;
  margin: 0 auto;
  padding: 0 1.5rem;
}
.logo {
  font-size: 2rem;
  font-weight: 800;
  background: linear-gradient(90deg, var(--accent), var(--accent2));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  letter-spacing: -0.5px;
}
.tagline {
  color: var(--text2);
  font-size: 0.9rem;
  margin-top: 0.3rem;
}

/* ── Date Nav ── */
.date-nav {
  background: var(--bg2);
  border-bottom: 1px solid var(--border);
  padding: 0.75rem 0;
  position: sticky;
  top: 0;
  z-index: 100;
  backdrop-filter: blur(8px);
}
.nav-inner {
  max-width: 1100px;
  margin: 0 auto;
  padding: 0 1.5rem;
  display: flex;
  align-items: center;
  gap: 0.5rem;
  flex-wrap: wrap;
}
.nav-label {
  color: var(--text2);
  font-size: 0.8rem;
  white-space: nowrap;
}
.date-nav a {
  color: var(--text2);
  text-decoration: none;
  font-size: 0.82rem;
  padding: 0.25rem 0.6rem;
  border-radius: 6px;
  border: 1px solid transparent;
  transition: all 0.2s;
}
.date-nav a:hover {
  color: var(--accent);
  border-color: var(--accent);
  background: rgba(79,142,247,0.08);
}
.date-nav a.active {
  color: var(--accent);
  border-color: var(--accent);
  background: rgba(79,142,247,0.12);
  font-weight: 600;
}

/* ── Main ── */
.main-content {
  max-width: 1100px;
  margin: 0 auto;
  padding: 2rem 1.5rem 4rem;
}
.page-meta {
  margin-bottom: 2rem;
  padding-bottom: 1.5rem;
  border-bottom: 1px solid var(--border);
}
.page-date {
  font-size: 1.6rem;
  font-weight: 700;
  color: var(--text);
}
.meta-info {
  color: var(--text2);
  font-size: 0.88rem;
  margin-top: 0.4rem;
}
.meta-info strong { color: var(--accent); }

/* ── Category Section ── */
.category-section { margin-bottom: 2.5rem; }
.category-title {
  font-size: 1.1rem;
  font-weight: 700;
  color: var(--text);
  margin-bottom: 1rem;
  padding: 0.5rem 0.8rem;
  background: var(--bg3);
  border-left: 3px solid var(--accent);
  border-radius: 0 8px 8px 0;
  display: flex;
  align-items: center;
  gap: 0.5rem;
}
.count {
  font-size: 0.8rem;
  color: var(--text2);
  font-weight: 400;
}

/* ── Cards ── */
.cards-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(320px, 1fr));
  gap: 1rem;
}
.card {
  background: var(--card-bg);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1.2rem;
  transition: transform 0.2s, border-color 0.2s, box-shadow 0.2s;
  display: flex;
  flex-direction: column;
  gap: 0.6rem;
}
.card:hover {
  transform: translateY(-2px);
  border-color: var(--accent);
  box-shadow: var(--shadow);
}
.card h3 {
  font-size: 0.95rem;
  font-weight: 600;
  line-height: 1.5;
}
.card h3 a {
  color: var(--text);
  text-decoration: none;
  transition: color 0.2s;
}
.card h3 a:hover { color: var(--accent); }
.summary {
  font-size: 0.82rem;
  color: var(--text2);
  line-height: 1.6;
  flex: 1;
  display: -webkit-box;
  -webkit-line-clamp: 3;
  -webkit-box-orient: vertical;
  overflow: hidden;
}
.card footer { margin-top: auto; }
.source-badge {
  font-size: 0.75rem;
  color: var(--text2);
  background: var(--bg3);
  padding: 0.2rem 0.5rem;
  border-radius: 4px;
}

/* ── Footer ── */
.site-footer {
  background: var(--bg2);
  border-top: 1px solid var(--border);
  padding: 1.5rem;
  text-align: center;
  color: var(--text2);
  font-size: 0.82rem;
  line-height: 2;
}
.site-footer a { color: var(--accent); text-decoration: none; }
.site-footer a:hover { text-decoration: underline; }

/* ── Responsive ── */
@media (max-width: 640px) {
  .logo { font-size: 1.5rem; }
  .cards-grid { grid-template-columns: 1fr; }
  .page-date { font-size: 1.2rem; }
}