/* ========================================
   AI for Research - 定制样式
   ======================================== */

:root {
  --accent: #2980b9;
  --accent-dark: #1a5276;
  --accent-light: #d4e6f1;
  --bg-warm: #fafbfc;
  --text-primary: #2c3e50;
  --text-secondary: #5d6d7e;
  --card-border: #e8ecf0;
  --card-shadow-hover: 0 6px 20px rgba(0,0,0,0.1);
}

body {
  font-family: "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "Noto Sans SC", sans-serif;
  color: var(--text-primary);
  background: var(--bg-warm);
  line-height: 1.75;
}

/* --- 导航栏 --- */
.navbar {
  font-size: 0.9rem;
  letter-spacing: 0.02em;
  box-shadow: 0 1px 4px rgba(0,0,0,0.08);
}

.navbar-brand { font-weight: 700; font-size: 1.05rem; }

.navbar .dropdown-menu {
  border: 1px solid #e0e0e0;
  border-radius: 8px;
  box-shadow: 0 4px 16px rgba(0,0,0,0.1);
  padding: 0.4rem 0;
  margin-top: 0.2rem;
  animation: fadeIn 0.15s ease;
}

@keyframes fadeIn {
  from { opacity: 0; transform: translateY(-4px); }
  to { opacity: 1; transform: translateY(0); }
}

.navbar .dropdown-item { padding: 0.4rem 1.2rem; font-size: 0.88rem; }
.navbar .dropdown-item:hover { background: var(--accent-light); color: var(--accent-dark); }
.navbar .dropdown-divider { margin: 0.25rem 0; }

/* --- Hero --- */
.hero-banner {
  background: linear-gradient(135deg, #1a2a3a 0%, #2c3e50 40%, #2980b9 100%);
  color: #fff;
  padding: 2.2rem 2rem 1.8rem;
  text-align: center;
}

.hero-banner h1 { font-size: 2rem; font-weight: 700; margin-bottom: 0.2rem; color: #fff; }
.hero-banner .subtitle { font-size: 0.95rem; color: rgba(255,255,255,0.75); margin: 0; }

/* --- 栏目标题 --- */
.cat-title {
  font-size: 1.2rem;
  font-weight: 600;
  color: var(--text-primary);
  margin: 1.8rem 0 0.8rem;
  padding-bottom: 0.4rem;
  border-bottom: 2px solid var(--accent);
  display: inline-block;
}

/* --- 课程区块 --- */
.course-block {
  background: #fff;
  border: 1px solid var(--card-border);
  border-radius: 10px;
  padding: 1.2rem 1.5rem 1rem;
  margin-bottom: 1rem;
}

.course-header {
  margin-bottom: 0.8rem;
}

.course-name {
  font-size: 1rem;
  font-weight: 600;
  color: var(--text-primary);
}

.course-desc {
  font-size: 0.82rem;
  color: var(--text-secondary);
  margin-left: 0.8rem;
}

/* --- 紧凑卡片行 --- */
.card-row {
  display: flex;
  flex-wrap: wrap;
  gap: 0.6rem;
}

a.mini-card { text-decoration: none; color: inherit; }

.mini-card {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  background: var(--bg-warm);
  border: 1px solid var(--card-border);
  border-radius: 8px;
  padding: 0.6rem 1rem;
  transition: all 0.2s ease;
  cursor: pointer;
}

.mini-card:hover {
  border-color: var(--accent);
  box-shadow: 0 2px 8px rgba(41,128,185,0.15);
  transform: translateY(-1px);
}

.mc-icon { font-size: 1.1rem; flex-shrink: 0; }
.mc-title { font-size: 0.88rem; font-weight: 500; color: var(--text-primary); white-space: nowrap; }

.mini-card.coming-soon {
  opacity: 0.5;
  cursor: default;
}
.mini-card.coming-soon:hover { transform: none; box-shadow: none; border-color: var(--card-border); }

/* --- 关于页面 --- */
.about-section {
  margin-bottom: 2rem;
}

.about-section h2 {
  font-size: 1.2rem;
  font-weight: 600;
  margin-bottom: 0.8rem;
  padding-bottom: 0.3rem;
  border-bottom: 1px solid #eee;
}

.about-section > p {
  font-size: 0.92rem;
  line-height: 1.8;
  color: var(--text-secondary);
}

.about-card {
  display: flex;
  gap: 2rem;
  align-items: flex-start;
  margin: 0.5rem 0;
}

.about-photo {
  flex-shrink: 0;
  width: 150px;
  padding-top: 0.2rem;
}

.about-photo img {
  width: 150px;
  height: auto;
  border-radius: 6px;
  box-shadow: 0 2px 8px rgba(0,0,0,0.1);
}

.about-info h3 {
  font-size: 1.3rem;
  font-weight: 600;
  margin: 0 0 0.15rem;
  line-height: 1.3;
}

.about-affil {
  font-size: 0.9rem;
  color: var(--text-secondary);
  margin-bottom: 0.8rem;
}

.about-info p {
  font-size: 0.92rem;
  line-height: 1.7;
  margin-bottom: 0.6rem;
}

.about-links {
  display: flex;
  gap: 1.5rem;
  margin-top: 1rem;
  padding-top: 0.8rem;
  border-top: 1px solid #eee;
}

.about-link-item {
  display: flex;
  align-items: center;
  gap: 0.4rem;
  font-size: 0.9rem;
  color: var(--accent);
  text-decoration: none;
  padding: 0.3rem 0;
}

.about-link-item:hover { color: var(--accent-dark); text-decoration: underline; }
.about-link-item span { font-size: 1rem; }

/* --- 侧边栏 --- */
.sidebar .sidebar-title { font-weight: 600; font-size: 0.95rem; }
.sidebar .sidebar-item .sidebar-item-text { font-size: 0.88rem; }

/* --- 内容页 --- */
.content h1 { font-size: 1.7rem; font-weight: 700; border-bottom: none; }
.content h2 { font-size: 1.3rem; font-weight: 600; margin-top: 2rem; padding-bottom: 0.3rem; border-bottom: 1px solid #eee; }
.content h3 { font-size: 1.1rem; font-weight: 600; margin-top: 1.5rem; }

.callout { border-radius: 8px; border-left-width: 4px; }

pre { border-radius: 8px; border: 1px solid #e8ecf0; }
code { font-size: 0.88em; }

/* --- 页脚 --- */
.nav-footer { font-size: 0.82rem; color: var(--text-secondary); border-top: 1px solid #e8ecf0; }

/* --- 响应式 --- */
@media (max-width: 768px) {
  .hero-banner { padding: 1.5rem 1rem; }
  .hero-banner h1 { font-size: 1.5rem; }
  .card-row { flex-direction: column; }
  .about-card { flex-direction: column; align-items: center; text-align: center; }
  .about-photo { width: 120px; }
  .course-header { display: flex; flex-direction: column; gap: 0.2rem; }
  .course-desc { margin-left: 0; }
}