/* 公共样式：变量、导航、面包屑、卡片、页脚 */
:root {
  --primary: #4361ee;
  --primary-light: #7b8cff;
  --accent: #4ecdc4;
  --radius: 16px;
  --shadow: 0 8px 32px rgba(0, 0, 0, 0.12);
}

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

body {
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'PingFang SC', 'Microsoft YaHei', sans-serif;
  min-height: 100vh;
  line-height: 1.6;
}

/* ========== 导航 ========== */
.site-nav {
  position: sticky;
  top: 0;
  z-index: 100;
  display: flex;
  align-items: center;
  gap: 6px;
  padding: 0 24px;
  min-height: 56px;
  background: rgba(15, 12, 41, 0.88);
  backdrop-filter: blur(12px);
  border-bottom: 1px solid rgba(255, 255, 255, 0.08);
}

.nav-brand {
  font-weight: 800;
  color: #fff;
  text-decoration: none;
  margin-right: 20px;
  font-size: 16px;
  letter-spacing: 0.5px;
}

.nav-item {
  position: relative;
}

.nav-link {
  display: flex;
  align-items: center;
  gap: 6px;
  color: rgba(255, 255, 255, 0.75);
  text-decoration: none;
  font-size: 14px;
  padding: 8px 12px;
  border-radius: 8px;
  transition: all .2s;
}

.nav-link:hover {
  color: #fff;
  background: rgba(255, 255, 255, 0.08);
}

.nav-dropdown {
  display: none;
  position: absolute;
  top: 100%;
  left: 0;
  min-width: 190px;
  background: rgba(30, 28, 60, 0.98);
  border: 1px solid rgba(255, 255, 255, 0.1);
  border-radius: 14px;
  padding: 8px;
  box-shadow: var(--shadow);
  margin-top: 6px;
}

.nav-item:hover .nav-dropdown {
  display: block;
}

.nav-dropdown a {
  display: flex;
  align-items: center;
  gap: 10px;
  color: rgba(255, 255, 255, 0.85);
  text-decoration: none;
  font-size: 13px;
  padding: 9px 14px;
  border-radius: 10px;
  transition: all .15s;
}

.nav-dropdown a:hover {
  background: rgba(255, 255, 255, 0.1);
  color: #fff;
}

/* ========== 亮色主题覆盖 ========== */
.theme-light .site-nav {
  background: rgba(248, 245, 240, 0.96);
  border-bottom-color: rgba(0, 0, 0, 0.06);
}

.theme-light .nav-brand {
  color: #2c2c2c;
}

.theme-light .nav-link {
  color: #555;
}

.theme-light .nav-link:hover {
  color: #111;
  background: rgba(0, 0, 0, 0.04);
}

.theme-light .nav-dropdown {
  background: #fff;
  border-color: rgba(0, 0, 0, 0.08);
}

.theme-light .nav-dropdown a {
  color: #444;
}

.theme-light .nav-dropdown a:hover {
  background: #f4f1ec;
  color: #111;
}

/* ========== 面包屑 ========== */
.breadcrumbs {
  display: flex;
  align-items: center;
  gap: 10px;
  flex-wrap: wrap;
  padding: 14px 24px;
  font-size: 13px;
}

.theme-dark .breadcrumbs {
  color: rgba(255, 255, 255, 0.45);
  background: rgba(0, 0, 0, 0.15);
}

.theme-dark .breadcrumbs a {
  color: var(--primary-light);
  text-decoration: none;
}

.theme-light .breadcrumbs {
  color: #888;
  background: #f0ebe4;
}

.theme-light .breadcrumbs a {
  color: #8B6914;
  text-decoration: none;
}

.breadcrumbs a:hover {
  text-decoration: underline;
}

.breadcrumbs .sep {
  opacity: .5;
}

/* ========== 通用卡片 ========== */
.card {
  background: rgba(255, 255, 255, 0.08);
  border: 1px solid rgba(255, 255, 255, 0.12);
  border-radius: var(--radius);
  backdrop-filter: blur(10px);
  transition: all .3s ease;
}

.card:hover {
  transform: translateY(-4px);
  box-shadow: 0 12px 40px rgba(67, 97, 238, 0.2);
  border-color: rgba(67, 97, 238, 0.4);
}

/* ========== 页脚 ========== */
.site-footer {
  text-align: center;
  padding: 32px 24px;
  font-size: 13px;
}

.theme-dark .site-footer {
  color: rgba(255, 255, 255, 0.35);
}

.theme-light .site-footer {
  color: #aaa;
}