/* ===== 机电学习站 样式 ===== */
* { margin: 0; padding: 0; box-sizing: border-box; }
:root {
  --primary: #1e3a5f;
  --accent: #f59e0b;
  --bg: #f5f7fa;
  --card: #ffffff;
  --text: #2d3748;
  --muted: #718096;
  --border: #e2e8f0;
}
html { scroll-behavior: smooth; }
body {
  font-family: "Microsoft YaHei", "PingFang SC", "Helvetica Neue", Arial, sans-serif;
  background: var(--bg);
  color: var(--text);
  line-height: 1.75;
}
.container { max-width: 1080px; margin: 0 auto; padding: 0 16px; }

/* ===== 顶部导航 ===== */
.site-header {
  background: var(--primary);
  color: #fff;
  position: sticky;
  top: 0;
  z-index: 100;
  box-shadow: 0 2px 8px rgba(0,0,0,.15);
}
.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 60px;
}
.logo { color: #fff; font-size: 1.25rem; font-weight: 700; text-decoration: none; }
.site-nav { display: flex; gap: 4px; }
.site-nav a {
  color: #cbd5e1;
  text-decoration: none;
  padding: 8px 14px;
  border-radius: 6px;
  font-size: .95rem;
  transition: all .2s;
}
.site-nav a:hover { color: #fff; background: rgba(255,255,255,.12); }
.site-nav a.active { color: #fff; background: var(--accent); font-weight: 600; }
.menu-btn {
  display: none;
  background: none;
  border: 1px solid rgba(255,255,255,.4);
  color: #fff;
  font-size: 1.2rem;
  border-radius: 6px;
  padding: 4px 12px;
  cursor: pointer;
}

/* ===== Hero ===== */
.hero {
  background: linear-gradient(135deg, var(--primary) 0%, #2d5a8e 100%);
  color: #fff;
  padding: 48px 24px;
  border-radius: 14px;
  margin: 24px 0;
  text-align: center;
}
.hero h1 { font-size: 1.9rem; margin-bottom: 10px; }
.hero p { color: #dbe7f5; max-width: 640px; margin: 0 auto; font-size: 1.02rem; }

/* ===== 布局 ===== */
.layout {
  display: grid;
  grid-template-columns: 1fr 300px;
  gap: 24px;
  margin-bottom: 40px;
}
.list-head {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 16px;
}
.list-head h2 { font-size: 1.35rem; color: var(--primary); }
.count-badge {
  background: var(--accent);
  color: #fff;
  font-size: .8rem;
  padding: 2px 12px;
  border-radius: 999px;
}

/* ===== 文章列表 ===== */
.article-list { display: flex; flex-direction: column; gap: 16px; }
.article-card {
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 20px 22px;
  text-decoration: none;
  color: var(--text);
  transition: all .2s;
  display: block;
}
.article-card:hover {
  box-shadow: 0 6px 20px rgba(30,58,95,.12);
  transform: translateY(-2px);
  border-color: var(--accent);
}
.article-card .card-title { font-size: 1.15rem; font-weight: 700; color: var(--primary); margin-bottom: 6px; }
.article-card:hover .card-title { color: var(--accent); }
.article-card .card-summary { font-size: .93rem; color: var(--muted); margin-bottom: 10px; }
.article-card .card-meta { font-size: .8rem; color: var(--muted); display: flex; gap: 12px; flex-wrap: wrap; }
.cat-tag {
  background: #e8f0fb;
  color: var(--primary);
  padding: 1px 10px;
  border-radius: 999px;
  font-size: .78rem;
}
.empty-tip { color: var(--muted); text-align: center; padding: 40px 0; }

/* ===== 侧边栏 ===== */
.sidebar { display: flex; flex-direction: column; gap: 16px; }
.side-card {
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 18px;
}
.side-card h3 { font-size: 1rem; color: var(--primary); margin-bottom: 10px; padding-bottom: 8px; border-bottom: 2px solid var(--border); }
.side-card p { font-size: .88rem; color: var(--muted); }
.cat-list { list-style: none; }
.cat-list li { margin-bottom: 6px; }
.cat-list a {
  color: var(--text);
  text-decoration: none;
  font-size: .92rem;
  display: flex;
  justify-content: space-between;
  padding: 6px 8px;
  border-radius: 6px;
  transition: all .2s;
}
.cat-list a:hover { background: #f0f4fa; color: var(--accent); }
.stat-list { list-style: none; font-size: .9rem; color: var(--muted); }
.stat-list li { padding: 4px 0; }
.stat-list b { color: var(--primary); }

/* ===== 文章详情 ===== */
.article-detail {
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: 14px;
  padding: 32px 36px;
  margin: 24px 0 40px;
}
.article-detail-head { margin-bottom: 20px; }
.article-detail-head h1 { font-size: 1.7rem; color: var(--primary); line-height: 1.4; margin-bottom: 10px; }
.art-meta { font-size: .84rem; color: var(--muted); display: flex; gap: 14px; flex-wrap: wrap; }
.article-body { font-size: 1rem; }
.article-body h2 { font-size: 1.35rem; color: var(--primary); margin: 26px 0 12px; padding-left: 12px; border-left: 4px solid var(--accent); }
.article-body h3 { font-size: 1.15rem; color: var(--primary); margin: 20px 0 10px; }
.article-body p { margin-bottom: 14px; }
.article-body ul, .article-body ol { margin: 0 0 14px 24px; }
.article-body li { margin-bottom: 6px; }
.article-body blockquote {
  background: #f8fafc;
  border-left: 4px solid var(--accent);
  padding: 10px 16px;
  margin: 14px 0;
  color: var(--muted);
  border-radius: 0 8px 8px 0;
}
.article-body code {
  background: #f1f5f9;
  padding: 2px 6px;
  border-radius: 4px;
  font-size: .9em;
}
.article-body pre {
  background: #0f172a;
  color: #e2e8f0;
  padding: 16px;
  border-radius: 10px;
  overflow-x: auto;
  margin: 14px 0;
}
.article-body pre code { background: none; color: inherit; padding: 0; }
.article-body table { border-collapse: collapse; width: 100%; margin: 14px 0; font-size: .92rem; }
.article-body th, .article-body td { border: 1px solid var(--border); padding: 8px 12px; text-align: left; }
.article-body th { background: #f0f4fa; color: var(--primary); }
.article-body img { max-width: 100%; border-radius: 8px; }
.article-nav {
  display: flex;
  justify-content: space-between;
  gap: 12px;
  margin-top: 28px;
  padding-top: 20px;
  border-top: 1px solid var(--border);
}
.article-nav a {
  color: var(--primary);
  text-decoration: none;
  font-size: .92rem;
  padding: 8px 14px;
  background: #f0f4fa;
  border-radius: 8px;
  transition: all .2s;
}
.article-nav a:hover { background: var(--accent); color: #fff; }
.article-nav .disabled { opacity: .4; pointer-events: none; }

/* ===== 页脚 ===== */
.site-footer {
  background: var(--primary);
  color: #cbd5e1;
  text-align: center;
  padding: 22px 0;
  font-size: .85rem;
}

/* ===== 响应式 ===== */
@media (max-width: 820px) {
  .layout { grid-template-columns: 1fr; }
  .sidebar { order: 2; }
  .menu-btn { display: block; }
  .site-nav {
    display: none;
    position: absolute;
    top: 60px;
    left: 0;
    right: 0;
    background: var(--primary);
    flex-direction: column;
    padding: 10px 16px 16px;
    box-shadow: 0 8px 16px rgba(0,0,0,.2);
  }
  .site-nav.open { display: flex; }
  .hero h1 { font-size: 1.5rem; }
  .article-detail { padding: 22px 18px; }
  .article-detail-head h1 { font-size: 1.35rem; }
}