/* ========== 全局样式 ========== */
:root {
  --primary: #1e5cb8;          /* 主蓝色-学术专业 */
  --primary-dark: #164785;
  --primary-light: #3d7cd1;
  --accent: #2da87a;            /* 辅助绿色-希望/通过 */
  --accent-dark: #207a5a;
  --warning: #e8a33d;
  --danger: #d9534f;
  --text: #1f2937;
  --text-light: #6b7280;
  --border: #e5e7eb;
  --bg: #f7f9fc;
  --bg-card: #ffffff;
  --shadow-sm: 0 1px 2px rgba(15,23,42,.05);
  --shadow: 0 4px 14px rgba(15,23,42,.08);
  --shadow-lg: 0 10px 30px rgba(15,23,42,.12);
  --radius: 10px;
}

* { box-sizing: border-box; }

html, body {
  margin: 0;
  padding: 0;
  font-family: "PingFang SC", "Microsoft YaHei", "Hiragino Sans GB", -apple-system, BlinkMacSystemFont, Arial, sans-serif;
  color: var(--text);
  background: var(--bg);
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
}

a { color: var(--primary); text-decoration: none; }
a:hover { color: var(--primary-dark); }
img { max-width: 100%; display: block; }

.container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 24px;
}

/* ========== 顶部导航 ========== */
.site-header {
  background: #fff;
  border-bottom: 1px solid var(--border);
  position: sticky;
  top: 0;
  z-index: 100;
  box-shadow: var(--shadow-sm);
}
.nav {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 68px;
}
.logo {
  display: flex;
  align-items: center;
  gap: 10px;
  font-weight: 700;
  font-size: 20px;
  color: var(--primary-dark);
}
.logo-icon {
  width: 36px;
  height: 36px;
  background: linear-gradient(135deg, var(--primary), var(--primary-light));
  border-radius: 8px;
  color: #fff;
  display: grid;
  place-items: center;
  font-size: 18px;
}
.nav-links {
  display: flex;
  gap: 6px;
  list-style: none;
  margin: 0;
  padding: 0;
}
.nav-links a {
  padding: 8px 14px;
  border-radius: 6px;
  color: var(--text);
  font-size: 15px;
  transition: all .2s;
}
.nav-links a:hover {
  background: rgba(30,92,184,.08);
  color: var(--primary);
}
.nav-links a.active {
  color: var(--primary);
  background: rgba(30,92,184,.1);
  font-weight: 600;
}
.nav-user {
  display: flex;
  align-items: center;
  gap: 10px;
}

/* ========== 按钮 ========== */
.btn {
  display: inline-block;
  padding: 10px 22px;
  border-radius: 8px;
  border: none;
  font-size: 15px;
  font-weight: 500;
  cursor: pointer;
  transition: all .2s;
  text-align: center;
}
.btn-primary {
  background: var(--primary);
  color: #fff;
}
.btn-primary:hover { background: var(--primary-dark); color: #fff; }
.btn-accent {
  background: var(--accent);
  color: #fff;
}
.btn-accent:hover { background: var(--accent-dark); color: #fff; }
.btn-outline {
  background: #fff;
  color: var(--primary);
  border: 1px solid var(--primary);
}
.btn-outline:hover { background: var(--primary); color: #fff; }
.btn-ghost {
  background: transparent;
  color: var(--text);
}
.btn-ghost:hover { background: rgba(0,0,0,.05); }
.btn-sm { padding: 6px 14px; font-size: 13px; }
.btn-lg { padding: 14px 32px; font-size: 16px; }
.btn-block { display: block; width: 100%; }

/* ========== 卡片 ========== */
.card {
  background: var(--bg-card);
  border-radius: var(--radius);
  padding: 24px;
  box-shadow: var(--shadow-sm);
  border: 1px solid var(--border);
}
.card-hover {
  transition: all .3s;
}
.card-hover:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-lg);
  border-color: var(--primary-light);
}

/* ========== 页脚 ========== */
.site-footer {
  background: #1a2639;
  color: #cbd5e1;
  padding: 40px 0 20px;
  margin-top: 60px;
}
.footer-grid {
  display: grid;
  grid-template-columns: 2fr 1fr 1fr 1fr;
  gap: 40px;
}
.footer-col h4 {
  color: #fff;
  margin: 0 0 16px;
  font-size: 16px;
}
.footer-col ul {
  list-style: none;
  padding: 0;
  margin: 0;
}
.footer-col li { margin-bottom: 10px; font-size: 14px; }
.footer-col a { color: #94a3b8; }
.footer-col a:hover { color: #fff; }
.footer-copy {
  margin-top: 32px;
  padding-top: 20px;
  border-top: 1px solid #334155;
  text-align: center;
  font-size: 13px;
  color: #64748b;
}

/* ========== 工具类 ========== */
.text-center { text-align: center; }
.text-primary { color: var(--primary); }
.text-accent { color: var(--accent); }
.text-muted { color: var(--text-light); }
.text-warning { color: var(--warning); }
.text-danger { color: var(--danger); }
.text-sm { font-size: 13px; }
.text-lg { font-size: 18px; }
.text-xl { font-size: 22px; }
.font-bold { font-weight: 700; }
.mt-1 { margin-top: 8px; }
.mt-2 { margin-top: 16px; }
.mt-3 { margin-top: 24px; }
.mt-4 { margin-top: 32px; }
.mb-1 { margin-bottom: 8px; }
.mb-2 { margin-bottom: 16px; }
.mb-3 { margin-bottom: 24px; }
.mb-4 { margin-bottom: 32px; }

.badge {
  display: inline-block;
  padding: 2px 10px;
  border-radius: 999px;
  font-size: 12px;
  font-weight: 500;
}
.badge-primary { background: rgba(30,92,184,.12); color: var(--primary); }
.badge-accent  { background: rgba(45,168,122,.12); color: var(--accent); }
.badge-warning { background: rgba(232,163,61,.15); color: var(--warning); }
.badge-danger  { background: rgba(217,83,79,.12);  color: var(--danger); }
.badge-gray    { background: #eef2f7; color: var(--text-light); }

/* ========== 响应式 ========== */
@media (max-width: 900px) {
  .nav-links { display: none; }
  .footer-grid { grid-template-columns: 1fr 1fr; }
}
@media (max-width: 600px) {
  .container { padding: 0 16px; }
  .footer-grid { grid-template-columns: 1fr; }
}

/* ========== 通用布局 ========== */
.page-hero {
  background: linear-gradient(135deg, var(--primary) 0%, var(--primary-light) 100%);
  color: #fff;
  padding: 50px 0;
}
.page-hero h1 { font-size: 32px; margin: 0 0 8px; }
.page-hero p { margin: 0; opacity: .9; font-size: 15px; }

.section { padding: 50px 0; }
.section-title {
  font-size: 26px;
  margin: 0 0 8px;
  color: var(--text);
}
.section-sub {
  color: var(--text-light);
  margin: 0 0 32px;
  font-size: 15px;
}

/* 表单 */
.form-group { margin-bottom: 18px; }
.form-label {
  display: block;
  font-size: 14px;
  color: var(--text);
  margin-bottom: 6px;
  font-weight: 500;
}
.form-control {
  width: 100%;
  padding: 10px 14px;
  border: 1px solid var(--border);
  border-radius: 8px;
  font-size: 15px;
  font-family: inherit;
  background: #fff;
  transition: all .2s;
}
.form-control:focus {
  outline: none;
  border-color: var(--primary);
  box-shadow: 0 0 0 3px rgba(30,92,184,.1);
}

/* 表格 */
.data-table {
  width: 100%;
  border-collapse: collapse;
  background: #fff;
  border-radius: 8px;
  overflow: hidden;
}
.data-table th {
  background: #f1f5f9;
  padding: 12px 14px;
  text-align: left;
  font-size: 14px;
  font-weight: 600;
  color: var(--text);
  border-bottom: 1px solid var(--border);
}
.data-table td {
  padding: 12px 14px;
  font-size: 14px;
  border-bottom: 1px solid var(--border);
}
.data-table tr:hover td { background: #f8fafc; }
.data-table tr:last-child td { border-bottom: 0; }

/* 提示信息 */
.alert {
  padding: 14px 16px;
  border-radius: 8px;
  border-left: 4px solid;
  font-size: 14px;
  margin-bottom: 16px;
}
.alert-info { background: #eff6ff; border-color: var(--primary); color: var(--primary-dark); }
.alert-success { background: #ecfdf5; border-color: var(--accent); color: var(--accent-dark); }
.alert-warning { background: #fffbeb; border-color: var(--warning); color: #92400e; }
.alert-danger { background: #fef2f2; border-color: var(--danger); color: #991b1b; }

/* 进度条 */
.progress {
  height: 8px;
  background: #e5e7eb;
  border-radius: 999px;
  overflow: hidden;
}
.progress-bar {
  height: 100%;
  background: linear-gradient(90deg, var(--primary), var(--primary-light));
  border-radius: 999px;
  transition: width .4s;
}

/* 模态框 */
.modal-mask {
  position: fixed;
  inset: 0;
  background: rgba(0,0,0,.5);
  display: none;
  align-items: center;
  justify-content: center;
  z-index: 1000;
}
.modal-mask.open { display: flex; }
.modal {
  background: #fff;
  border-radius: 12px;
  max-width: 500px;
  width: 90%;
  padding: 28px;
  box-shadow: var(--shadow-lg);
}
.modal h3 { margin: 0 0 12px; }