/* ===== 科技前沿博客 - 主样式 ===== */

/* --- CSS 变量（支持暗色模式） --- */
:root {
  --bg: #f1f5f9;
  --surface: #ffffff;
  --text: #1e293b;
  --text-secondary: #64748b;
  --primary: #2563eb;
  --primary-hover: #1d4ed8;
  --border: #e2e8f0;
  --shadow: 0 1px 3px rgba(0,0,0,0.08);
  --shadow-hover: 0 4px 12px rgba(0,0,0,0.12);
  --radius: 8px;
  --header-bg: #ffffff;
  --card-bg: #ffffff;
  --code-bg: #f1f5f9;
}

/* 暗色模式 */
@media (prefers-color-scheme: dark) {
  :root {
    --bg: #0f172a;
    --surface: #1e293b;
    --text: #e2e8f0;
    --text-secondary: #94a3b8;
    --border: #334155;
    --shadow: 0 1px 3px rgba(0,0,0,0.3);
    --shadow-hover: 0 4px 12px rgba(0,0,0,0.4);
    --header-bg: #1e293b;
    --card-bg: #1e293b;
    --code-bg: #0f172a;
  }
}

/* --- Reset --- */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
html { scroll-behavior: smooth; }
body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Noto Sans SC", sans-serif;
  background: var(--bg);
  color: var(--text);
  line-height: 1.7;
  min-height: 100vh;
}

/* --- 头部导航 --- */
header {
  background: var(--header-bg);
  border-bottom: 1px solid var(--border);
  padding: 0 24px;
  position: sticky;
  top: 0;
  z-index: 100;
  box-shadow: var(--shadow);
}
header .header-inner {
  max-width: 1200px;
  margin: 0 auto;
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 60px;
}
header h1 {
  font-size: 1.3rem;
  font-weight: 700;
}
header h1 a {
  color: var(--primary);
  text-decoration: none;
}
header nav {
  display: flex;
  gap: 20px;
  align-items: center;
}
header nav a {
  color: var(--text-secondary);
  text-decoration: none;
  font-size: 0.95rem;
  font-weight: 500;
  transition: color 0.2s;
}
header nav a:hover {
  color: var(--primary);
}

/* --- 主布局（文章 + 侧边栏） --- */
main {
  max-width: 1200px;
  margin: 32px auto;
  padding: 0 24px;
  display: grid;
  grid-template-columns: 1fr 300px;
  gap: 32px;
}
@media (max-width: 860px) {
  main { grid-template-columns: 1fr; }
}

/* --- 文章卡片 --- */
.post-list { display: flex; flex-direction: column; gap: 20px; }

.post-card {
  background: var(--card-bg);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 24px;
  transition: box-shadow 0.2s, transform 0.2s;
}
.post-card:hover {
  box-shadow: var(--shadow-hover);
  transform: translateY(-2px);
}
.post-card h2 {
  font-size: 1.2rem;
  font-weight: 600;
  margin-bottom: 8px;
}
.post-card h2 a {
  color: var(--text);
  text-decoration: none;
}
.post-card h2 a:hover {
  color: var(--primary);
}
.post-card .post-meta {
  font-size: 0.85rem;
  color: var(--text-secondary);
  margin-bottom: 10px;
  display: flex;
  align-items: center;
  gap: 12px;
  flex-wrap: wrap;
}
.post-card .tag {
  background: var(--code-bg);
  color: var(--primary);
  padding: 2px 8px;
  border-radius: 4px;
  font-size: 0.8rem;
  font-weight: 500;
}
.post-card .excerpt {
  color: var(--text-secondary);
  font-size: 0.95rem;
  line-height: 1.6;
}

/* --- 侧边栏 --- */
.sidebar {
  display: flex;
  flex-direction: column;
  gap: 20px;
}
@media (max-width: 860px) {
  .sidebar { order: -1; }
}

.sidebar-box {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 20px;
}
.sidebar-box h3 {
  font-size: 1rem;
  font-weight: 600;
  margin-bottom: 12px;
  color: var(--text);
}

/* 广告位 */
.ad-box {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 16px;
  text-align: center;
  min-height: 250px;
  display: flex;
  align-items: center;
  justify-content: center;
  flex-direction: column;
  gap: 8px;
}
.ad-box .ad-label {
  font-size: 0.75rem;
  color: var(--text-secondary);
  text-transform: uppercase;
  letter-spacing: 0.05em;
}
.ad-placeholder {
  width: 100%;
  min-height: 200px;
  background: var(--code-bg);
  border-radius: 4px;
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--text-secondary);
  font-size: 0.85rem;
}

/* --- Hero 区域 --- */
.hero-section {
  background: linear-gradient(135deg, var(--primary) 0%, #7c3aed 100%);
  color: white;
  padding: 48px 32px;
  border-radius: var(--radius);
  margin-bottom: 32px;
  text-align: center;
}
.hero-section h1 {
  font-size: 1.8rem;
  font-weight: 700;
  margin-bottom: 8px;
}
.hero-section .post-count {
  font-size: 1.1rem;
  opacity: 0.9;
}

/* --- 分页 --- */
.pagination-note {
  text-align: center;
  color: var(--text-secondary);
  font-size: 0.9rem;
  padding: 20px 0;
}

/* --- 文章页（post.html） --- */
.post-header {
  background: var(--surface);
  border-bottom: 1px solid var(--border);
  padding: 32px 0 24px;
  margin-bottom: 32px;
}
.post-header h1 {
  max-width: 800px;
  margin: 0 auto 12px;
  padding: 0 24px;
  font-size: 2rem;
  font-weight: 700;
  line-height: 1.3;
}
.post-header .post-meta {
  max-width: 800px;
  margin: 0 auto;
  padding: 0 24px;
  color: var(--text-secondary);
  font-size: 0.9rem;
  display: flex;
  gap: 16px;
  flex-wrap: wrap;
}
.post-content {
  max-width: 800px;
  margin: 0 auto;
  padding: 0 24px 64px;
  line-height: 1.8;
  font-size: 1.05rem;
}
.post-content h2 { font-size: 1.4rem; margin: 32px 0 16px; }
.post-content h3 { font-size: 1.2rem; margin: 24px 0 12px; }
.post-content p { margin-bottom: 16px; }
.post-content code {
  background: var(--code-bg);
  padding: 2px 6px;
  border-radius: 4px;
  font-size: 0.9em;
}
.post-content pre {
  background: var(--code-bg);
  padding: 16px;
  border-radius: var(--radius);
  overflow-x: auto;
  margin-bottom: 16px;
}

/* --- Footer --- */
footer {
  background: var(--surface);
  border-top: 1px solid var(--border);
  padding: 32px 24px;
  text-align: center;
  color: var(--text-secondary);
  font-size: 0.9rem;
}

/* --- 响应式 --- */
@media (max-width: 640px) {
  header .header-inner { flex-direction: column; height: auto; padding: 12px 0; gap: 8px; }
  main { padding: 0 12px; }
  .hero-section { padding: 32px 16px; }
  .hero-section h1 { font-size: 1.4rem; }
  .post-card { padding: 16px; }
  .post-header h1 { font-size: 1.5rem; }
}