:root{
  --bg:#f4f5f7; --panel:#fff; --border:#dfe1e6; --text:#172b4d;
  --muted:#6b778c; --primary:#0052cc; --primary-h:#0047b3;
  --danger:#de350b; --success:#00875a; --warn:#ff991f;
  --shadow:0 1px 3px rgba(9,30,66,.12);
}
*{box-sizing:border-box}
body{margin:0;font-family:-apple-system,BlinkMacSystemFont,"Segoe UI","PingFang SC","Microsoft YaHei",sans-serif;
  background:var(--bg);color:var(--text);font-size:14px}
a{color:var(--primary);text-decoration:none}
.muted{color:var(--muted)}
.mono{font-family:ui-monospace,Menlo,Consolas,monospace;font-size:12px}
.spacer{flex:1}

.btn{border:1px solid var(--border);background:#fff;color:var(--text);
  padding:7px 14px;border-radius:4px;cursor:pointer;font-size:14px}
.btn:hover{background:#f0f1f3}
.btn.primary{background:var(--primary);border-color:var(--primary);color:#fff}
.btn.primary:hover{background:var(--primary-h)}
.btn.danger{background:#fff;border-color:var(--danger);color:var(--danger)}
.btn.ghost{border-color:transparent;background:transparent}
.btn.small{padding:4px 10px;font-size:12px}
input,select,textarea{font-family:inherit;font-size:14px;padding:7px 9px;border:1px solid var(--border);
  border-radius:4px;background:#fff;color:var(--text);width:100%}
input:focus,select:focus,textarea:focus{outline:none;border-color:var(--primary);box-shadow:0 0 0 2px rgba(0,82,204,.15)}

/* 顶栏 */
.topbar{display:flex;align-items:center;gap:12px;padding:10px 18px;background:#fff;
  border-bottom:1px solid var(--border);position:sticky;top:0;z-index:20}
.brand{font-weight:700;color:var(--primary);font-size:16px}
.topbar .tabs{display:flex;gap:6px}
.topbar .tabs a{padding:6px 12px;border-radius:4px;color:var(--text)}
.topbar .tabs a:hover{background:#f0f1f3}
.topbar .tabs a.active{background:#e9f2ff;color:var(--primary);font-weight:600}
.user-chip{font-size:13px;color:var(--muted)}
.user-chip b{color:var(--text)}

/* 布局 */
main{padding:20px;max-width:1400px;margin:0 auto}
.toolbar{display:flex;gap:10px;align-items:center;flex-wrap:wrap;margin-bottom:14px}
.toolbar select{width:auto;min-width:150px}
.toolbar input{width:auto}

/* 统计卡片 */
.stats{display:grid;grid-template-columns:repeat(auto-fit,minmax(150px,1fr));gap:12px;margin-bottom:20px}
.stat{background:#fff;padding:14px 16px;border-radius:6px;box-shadow:var(--shadow)}
.stat .k{font-size:12px;color:var(--muted);text-transform:uppercase;letter-spacing:.5px}
.stat .v{font-size:24px;font-weight:700;margin-top:4px}

/* 表格 */
.table{width:100%;border-collapse:collapse;background:#fff;border-radius:6px;overflow:hidden;box-shadow:var(--shadow)}
.table th{text-align:left;padding:11px 14px;background:#fafbfc;border-bottom:1px solid var(--border);
  font-size:12px;text-transform:uppercase;color:var(--muted);white-space:nowrap}
.table td{padding:11px 14px;border-bottom:1px solid #f0f1f3;vertical-align:top}
.table tr.row{cursor:pointer}
.table tr.row:hover td{background:#f7f8f9}

/* 标签 */
.tag{display:inline-block;font-size:11px;padding:2px 8px;border-radius:10px;background:#ebecf0;color:var(--muted);white-space:nowrap}
.tag.blue{background:#deebff;color:#0747a6}
.tag.green{background:#e3fcef;color:#006644}
.tag.yellow{background:#fffae6;color:#974f0c}
.tag.red{background:#ffebe6;color:#bf2600}
.tag.purple{background:#eae6ff;color:#403294}

/* 弹窗 */
.modal{position:fixed;inset:0;background:rgba(9,30,66,.5);display:flex;align-items:center;justify-content:center;z-index:50;padding:20px}
.modal[hidden]{display:none}
.modal-box{background:#fff;padding:24px;border-radius:8px;width:100%;max-width:640px;max-height:90vh;overflow-y:auto}
.modal-box h3{margin:0 0 16px}
.modal-box label{display:block;margin-bottom:12px;font-size:13px;font-weight:600;color:var(--muted)}
.modal-box label input,.modal-box label select,.modal-box label textarea{margin-top:5px;font-weight:400;color:var(--text)}
.modal-actions{display:flex;justify-content:flex-end;gap:10px;margin-top:16px}

/* ========== 登录页（带背景图） ========== */
.login-page{
  display:flex;
  align-items:center;
  justify-content:center;
  min-height:100vh;
  padding:20px;
  padding-bottom:80px;
  background-color:#e8eef5;
  background-image:url('/bg.webp');
  background-size:cover;
  background-position:center;
  background-repeat:no-repeat;
}
.login-box{
  background:rgba(255,255,255,0.92);
  backdrop-filter:blur(8px);
  -webkit-backdrop-filter:blur(8px);
  padding:32px;
  border-radius:10px;
  box-shadow:0 8px 32px rgba(9,30,66,.25);
  width:100%;
  max-width:420px;
}
.login-box h1{margin:0 0 4px;font-size:22px;color:var(--primary)}
.login-box label{display:block;margin-bottom:12px;font-size:13px;font-weight:600;color:var(--muted)}
.login-box label input,.login-box label select{margin-top:5px;font-weight:400;color:var(--text)}
.tabs-line{display:flex;gap:8px;margin:18px 0}
.tabs-line button{flex:1;padding:8px;border:1px solid var(--border);background:#fff;border-radius:4px;cursor:pointer}
.tabs-line button.active{background:var(--primary);border-color:var(--primary);color:#fff}
.msg{margin-top:14px;font-size:13px;color:var(--danger);min-height:18px}
.msg.ok{color:var(--success)}
hr{border:none;border-top:1px solid var(--border);margin:22px 0}

/* 详情 */
.detail-main{max-width:900px;margin:0 auto}
.detail-main h2{margin:6px 0 18px;font-size:22px}
.field{margin-bottom:16px}
.field>label{display:block;font-size:12px;font-weight:600;color:var(--muted);
  text-transform:uppercase;margin-bottom:6px}
.card{background:#fff;border-radius:6px;padding:16px;box-shadow:var(--shadow);margin-bottom:16px}
.grid{display:grid;grid-template-columns:repeat(auto-fit,minmax(200px,1fr));gap:12px}
.img-grid{display:grid;grid-template-columns:repeat(auto-fill,minmax(140px,1fr));gap:8px;margin-top:10px}
.img-grid .item{position:relative;border-radius:4px;overflow:hidden;border:1px solid var(--border);background:#000}
.img-grid img{width:100%;height:120px;object-fit:cover;display:block;cursor:pointer}
.img-grid .del{position:absolute;top:4px;right:4px;background:rgba(0,0,0,.6);color:#fff;border:none;
  border-radius:3px;padding:2px 6px;cursor:pointer;font-size:12px}

/* ========== 日历 ========== */
.calendar{background:#fff;border-radius:6px;box-shadow:var(--shadow);padding:16px}
.calendar-head{display:flex;align-items:center;gap:12px;margin-bottom:16px}
.calendar-head h3{margin:0;flex:1;text-align:center;font-size:18px}
.calendar-grid{display:grid;grid-template-columns:repeat(7,1fr);gap:4px}
.calendar-dow{text-align:center;font-size:12px;color:var(--muted);font-weight:600;padding:8px 0;text-transform:uppercase}
.calendar-day{min-height:90px;border:1px solid var(--border);border-radius:4px;padding:6px;background:#fff;font-size:12px;overflow:hidden}
.calendar-day.other-month{background:#fafbfc;color:#c1c7d0}
.calendar-day.today{border-color:var(--primary);background:#f0f7ff;box-shadow:0 0 0 2px rgba(0,82,204,.15)}
.calendar-day .day-num{font-weight:700;margin-bottom:4px}
.calendar-event{background:#deebff;color:#0747a6;padding:2px 5px;border-radius:3px;margin-bottom:2px;font-size:11px;
  overflow:hidden;text-overflow:ellipsis;white-space:nowrap;cursor:pointer}
.calendar-event:hover{opacity:.8}
.calendar-event.teach{background:#e3fcef;color:#006644}
.calendar-event.flagship{background:#eae6ff;color:#403294}

/* ========== 带教空闲日历 ========== */
.calendar-day.available{
  border-color:#00875a;
  background:#f0fff5;
  box-shadow:0 0 0 2px rgba(0,135,90,.15);
}
.calendar-day .avail-badge{
  display:inline-block;
  font-size:10px;
  padding:0 4px;
  border-radius:6px;
  background:#00875a;
  color:#fff;
  margin-left:4px;
  vertical-align:middle;
}
.calendar-day.has-mentors{
  border-color:#00875a;
  background:#f0fff5;
}
.mentor-avail-tag{
  background:#e3fcef;
  color:#006644;
  padding:2px 5px;
  border-radius:3px;
  margin-bottom:2px;
  font-size:11px;
  overflow:hidden;
  text-overflow:ellipsis;
  white-space:nowrap;
}

/* ========== 评论区 ========== */
.comment-item{padding:12px 14px;background:#fafbfc;border-radius:6px;margin-bottom:10px;border-left:3px solid var(--border)}
.comment-item.reject{background:#fff5f5;border-left-color:var(--danger)}
.comment-item .c-head{display:flex;align-items:center;gap:8px;font-size:13px;margin-bottom:6px;flex-wrap:wrap}
.comment-item .c-body{line-height:1.6;white-space:pre-wrap;word-break:break-word}

/* ========== 用户菜单下拉 ========== */
.user-menu{position:relative}
.user-chip-btn{
  border:1px solid var(--border);background:#fff;color:var(--text);
  padding:5px 12px;border-radius:4px;cursor:pointer;font-size:13px;
  display:flex;align-items:center;gap:6px;
}
.user-chip-btn:hover{background:#f0f1f3}
.user-chip-btn b{color:var(--text)}
.user-chip-btn::after{content:'▾';font-size:10px;color:var(--muted)}
.user-dropdown{
  position:absolute;right:0;top:calc(100% + 6px);background:#fff;
  border:1px solid var(--border);border-radius:6px;box-shadow:0 4px 16px rgba(9,30,66,.15);
  min-width:160px;padding:6px 0;z-index:100;
}
.user-dropdown .dropdown-item{
  display:block;padding:9px 16px;color:var(--text);font-size:14px;cursor:pointer;
}
.user-dropdown .dropdown-item:hover{background:#f0f1f3}
.user-dropdown .dropdown-item.danger{color:var(--danger)}

/* ========== 个人信息页面 ========== */
.profile-page{max-width:640px;margin:0 auto}
.profile-header{background:#fff;border-radius:6px;box-shadow:var(--shadow);padding:20px;margin-bottom:16px;display:flex;align-items:center;gap:16px}
.profile-avatar{
  width:64px;height:64px;border-radius:50%;background:var(--primary);color:#fff;
  display:flex;align-items:center;justify-content:center;font-size:26px;font-weight:700;
}
.profile-info{flex:1}
.profile-info .name{font-size:20px;font-weight:700;margin-bottom:4px}
.profile-info .meta{font-size:13px;color:var(--muted)}

/* ========== 底部备案栏 ========== */
.footer-beian{
  background:#66ccff;
  text-align:center;
  padding:14px 20px;
  font-size:13px;
  color:#172b4d;
  line-height:1.8;
}
.footer-beian a{
  color:#172b4d;
  text-decoration:none;
  margin:0 12px;
  white-space:nowrap;
  display:inline-flex;
  align-items:center;
  gap:4px;
  vertical-align:middle;
}
.footer-beian a:hover{text-decoration:underline}
.footer-beian .beian-icon{
  width:16px;
  height:16px;
  vertical-align:middle;
  flex-shrink:0;
}
.footer-beian-fixed{
  position:fixed;
  bottom:0;left:0;right:0;
  z-index:5;
}

/* ========== 移动端适配 ========== */
@media (max-width: 768px){
  .topbar{flex-wrap:wrap;padding:10px 12px;gap:8px}
  .topbar .tabs{flex-wrap:wrap;width:100%}
  .topbar .tabs a{padding:6px 10px;font-size:13px}
  main{padding:12px}
  .table{font-size:12px}
  .table th,.table td{padding:8px 10px}
  .stats{grid-template-columns:repeat(auto-fit,minmax(110px,1fr));gap:8px}
  .stat{padding:10px 12px}
  .stat .v{font-size:20px}
  .detail-main{max-width:100%}
  .grid{grid-template-columns:1fr !important}
  .calendar-day{min-height:60px;padding:4px}
  .calendar-event{font-size:10px}
  .login-box{padding:24px}
  .modal-box{padding:18px}
  .profile-header{flex-direction:column;text-align:center}
  .footer-beian{font-size:12px;padding:12px 10px}
  .footer-beian a{display:block;margin:4px 0}
  .login-page{padding-bottom:100px}
}