/* ==========================================================================
 * 电子教室管理平台 · 后台样式（类 Element Plus 视觉语言）
 * ==========================================================================*/
:root{
  --brand:#2f6bdf; --brand-dark:#1f4fb0; --brand-light:#eaf1ff;
  --ok:#28a745; --warn:#e6a23c; --danger:#f0453a; --info:#909399;
  --bg:#f5f7fa; --card:#fff; --line:#e4e7ed; --line-soft:#f0f2f5;
  --t1:#303133; --t2:#606266; --t3:#909399;
  --r:8px; --side:210px;
}
*{box-sizing:border-box;margin:0;padding:0}
html,body{height:100%}
body{
  font:14px/1.6 "Microsoft YaHei","PingFang SC","Helvetica Neue",Arial,sans-serif;
  color:var(--t1);background:var(--bg);-webkit-font-smoothing:antialiased;
}
a{text-decoration:none;color:inherit}

/* ---------- 通用控件 ---------- */
.btn{
  display:inline-flex;align-items:center;justify-content:center;gap:5px;
  height:32px;padding:0 15px;border:1px solid var(--line);background:#fff;color:var(--t2);
  border-radius:6px;cursor:pointer;font-size:13px;white-space:nowrap;transition:.15s;
  font-family:inherit;line-height:1;
}
.btn:hover{color:var(--brand);border-color:#bcd3ff;background:var(--brand-light)}
.btn-primary{background:var(--brand);border-color:var(--brand);color:#fff}
.btn-primary:hover{background:var(--brand-dark);border-color:var(--brand-dark);color:#fff}
.btn-danger{background:#fff;border-color:#fbc4c4;color:var(--danger)}
.btn-danger:hover{background:var(--danger);border-color:var(--danger);color:#fff}
.btn-success{background:var(--ok);border-color:var(--ok);color:#fff}
.btn-success:hover{opacity:.88;color:#fff}
.btn-ghost{border-color:transparent;background:transparent}
.btn-sm{height:28px;padding:0 10px;font-size:12px}
.btn-block{width:100%;height:38px;font-size:14px}
.btn:disabled{opacity:.5;cursor:not-allowed}

.input,.select,.textarea{
  width:100%;height:32px;padding:0 10px;border:1px solid var(--line);border-radius:6px;
  outline:none;font-size:13px;color:var(--t1);background:#fff;font-family:inherit;transition:.15s;
}
.textarea{height:auto;padding:7px 10px;resize:vertical;line-height:1.6}
.input:focus,.select:focus,.textarea:focus{border-color:var(--brand);box-shadow:0 0 0 2px rgba(47,107,223,.12)}
.input::placeholder,.textarea::placeholder{color:#b8bcc4}
.select{cursor:pointer}

.field{margin-bottom:14px}
.field>label{display:block;font-size:13px;color:var(--t2);margin-bottom:6px}
.field .hint{font-size:12px;color:var(--t3);margin-top:5px}

/* ---------- 表格 ---------- */
.table{width:100%;border-collapse:collapse;font-size:13px}
.table th{
  text-align:left;padding:11px 12px;background:#fafbfc;color:var(--t2);
  font-weight:600;border-bottom:1px solid var(--line);white-space:nowrap;
}
.table td{padding:11px 12px;border-bottom:1px solid var(--line-soft);color:var(--t1);vertical-align:middle}
.table tbody tr:hover{background:#f8fafe}
.table .op a{margin-right:10px;color:var(--brand);cursor:pointer;font-size:13px}
.table .op a.danger{color:var(--danger)}
.table .op a:hover{text-decoration:underline}
.table-empty{padding:40px;text-align:center;color:var(--t3);font-size:13px}

/* ---------- 卡片 / 工具条 ---------- */
.card{background:var(--card);border-radius:var(--r);border:1px solid var(--line-soft);overflow:hidden}
.card-head{padding:14px 16px;border-bottom:1px solid var(--line-soft);display:flex;align-items:center;justify-content:space-between;gap:10px;flex-wrap:wrap}
.card-head h3{font-size:15px;font-weight:600}
.card-body{padding:16px}
.toolbar{display:flex;gap:9px;align-items:center;flex-wrap:wrap;margin-bottom:14px}
.toolbar .input,.toolbar .select{width:auto;min-width:150px}
.toolbar .spacer{flex:1}

.tag{display:inline-block;padding:1px 8px;border-radius:4px;font-size:12px;line-height:20px}
.tag-ok{background:#e9f7ec;color:var(--ok)}
.tag-off{background:#f0f1f3;color:var(--t3)}
.tag-warn{background:#fdf3e6;color:var(--warn)}
.tag-brand{background:var(--brand-light);color:var(--brand)}
.tag-danger{background:#fdecea;color:var(--danger)}

/* ---------- 布局 ---------- */
.layout{display:flex;min-height:100vh}
.sidebar{
  width:var(--side);flex:0 0 var(--side);background:#20304a;color:#c8d2e0;
  display:flex;flex-direction:column;position:fixed;top:0;bottom:0;left:0;
}
.brand{display:flex;align-items:center;gap:10px;padding:16px 16px 14px;border-bottom:1px solid rgba(255,255,255,.08)}
.brand-logo{
  width:32px;height:32px;border-radius:7px;background:var(--brand);color:#fff;
  display:flex;align-items:center;justify-content:center;font-weight:700;font-size:17px;flex:0 0 32px;
}
.brand-info b{display:block;color:#fff;font-size:14px;line-height:1.3}
.brand-info span{display:block;font-size:11px;color:#7f8ea8;margin-top:2px;overflow:hidden;text-overflow:ellipsis;white-space:nowrap;max-width:145px}
.nav{flex:1;padding:10px 8px;overflow-y:auto}
.nav-item{
  display:flex;align-items:center;gap:9px;padding:9px 11px;border-radius:6px;
  color:#c8d2e0;font-size:13.5px;margin-bottom:2px;cursor:pointer;transition:.15s;
}
.nav-item:hover{background:rgba(255,255,255,.07);color:#fff}
.nav-item.active{background:var(--brand);color:#fff}
.nav-icon{width:18px;text-align:center;font-size:14px;flex:0 0 18px}
.sidebar-foot{padding:11px 16px;font-size:11px;color:#6b7a91;border-top:1px solid rgba(255,255,255,.08)}

.main{margin-left:var(--side);flex:1;min-width:0;display:flex;flex-direction:column}
.topbar{
  height:56px;background:#fff;border-bottom:1px solid var(--line-soft);
  display:flex;align-items:center;justify-content:space-between;padding:0 20px;
  position:sticky;top:0;z-index:20;
}
.topbar-title{font-size:16px;font-weight:600}
.topbar-right{display:flex;align-items:center;gap:12px}
.topbar-right .user{font-size:13px;color:var(--t2)}
.chip{padding:3px 10px;background:var(--brand-light);color:var(--brand);border-radius:12px;font-size:12px}
.content{padding:18px 20px 30px;flex:1}
/* 底部版权条 */
.main-foot{flex:none;padding:9px 20px;border-top:1px solid var(--line);background:#fff;
  font-size:12px;color:var(--t3);text-align:center;letter-spacing:.2px}

/* ---------- 统计卡 ---------- */
.stat-grid{display:grid;grid-template-columns:repeat(auto-fit,minmax(170px,1fr));gap:14px;margin-bottom:16px}
.stat{background:#fff;border:1px solid var(--line-soft);border-radius:var(--r);padding:16px 18px}
.stat .label{font-size:13px;color:var(--t3)}
.stat .value{font-size:26px;font-weight:600;margin-top:6px;color:var(--t1);line-height:1.2}
.stat .value.brand{color:var(--brand)}
.stat .value.ok{color:var(--ok)}
.stat .foot{font-size:12px;color:var(--t3);margin-top:6px}

/* ---------- 抽屉 / 弹窗 ---------- */
.mask{position:fixed;inset:0;background:rgba(0,0,0,.42);z-index:100;display:none}
.mask.show{display:block}
.drawer{
  position:fixed;top:0;right:0;bottom:0;width:520px;max-width:96vw;background:#fff;z-index:101;
  transform:translateX(100%);transition:transform .22s ease;display:flex;flex-direction:column;
  box-shadow:-3px 0 14px rgba(0,0,0,.1);
}
.drawer.show{transform:translateX(0)}
.drawer-head{padding:15px 18px;border-bottom:1px solid var(--line-soft);display:flex;align-items:center;justify-content:space-between}
.drawer-head b{font-size:15px}
.drawer-head a{color:var(--t3);font-size:16px;cursor:pointer}
.drawer-body{padding:18px;overflow-y:auto;flex:1}

.modal{
  position:fixed;top:50%;left:50%;transform:translate(-50%,-50%);background:#fff;
  border-radius:10px;width:440px;max-width:94vw;z-index:102;display:none;
  box-shadow:0 8px 30px rgba(0,0,0,.18);
}
.modal.show{display:block}
.modal-head{padding:15px 18px;border-bottom:1px solid var(--line-soft);font-weight:600}
.modal-body{padding:18px}
.modal-foot{padding:12px 18px;border-top:1px solid var(--line-soft);text-align:right;display:flex;gap:9px;justify-content:flex-end}

/* ---------- Toast ---------- */
.toast-wrap{position:fixed;top:18px;left:50%;transform:translateX(-50%);z-index:200;display:flex;flex-direction:column;gap:8px;align-items:center}
.toast{
  padding:9px 18px;background:#fff;border:1px solid var(--line);border-radius:6px;
  box-shadow:0 3px 12px rgba(0,0,0,.1);font-size:13px;animation:tin .22s ease;
}
.toast.ok{border-left:3px solid var(--ok)}
.toast.err{border-left:3px solid var(--danger)}
.toast.info{border-left:3px solid var(--brand)}
@keyframes tin{from{opacity:0;transform:translateY(-8px)}to{opacity:1;transform:none}}

/* ---------- 登录页 ---------- */
.login-body{background:linear-gradient(135deg,#2a4d8f 0%,#2f6bdf 55%,#4f8ef0 100%);display:flex;align-items:center;justify-content:center;min-height:100vh;padding:20px}
.login-wrap{width:100%;max-width:400px}
.login-card{background:#fff;border-radius:12px;padding:32px 30px 26px;box-shadow:0 10px 40px rgba(0,0,0,.16)}
.login-brand{display:flex;align-items:center;gap:12px;margin-bottom:24px}
.login-logo{width:42px;height:42px;border-radius:9px;background:var(--brand);color:#fff;display:flex;align-items:center;justify-content:center;font-size:22px;font-weight:700;flex:0 0 42px}
.login-brand h1{font-size:19px;font-weight:600}
.login-brand p{font-size:12.5px;color:var(--t3);margin-top:2px}
.login-card .field>label{font-size:13px;color:var(--t2)}
.login-err{color:var(--danger);font-size:13px;min-height:20px;margin-bottom:6px}
.login-foot{margin-top:14px;font-size:12px;color:var(--t3);text-align:center;line-height:1.7}
.login-tip{margin-top:18px;padding-top:14px;border-top:1px dashed var(--line);font-size:12px;color:var(--t2);line-height:1.9}
.login-tip .dim{color:var(--t3)}

/* ---------- 课堂模式 / 特殊组件 ---------- */
.mode-badge{display:inline-block;padding:1px 7px;border-radius:4px;font-size:12px}
.mode-lan{background:#e9f7ec;color:var(--ok)}
.mode-wan{background:var(--brand-light);color:var(--brand)}

.member-pick{max-height:300px;overflow-y:auto;border:1px solid var(--line);border-radius:6px;padding:8px}
.member-pick label{display:flex;align-items:center;gap:8px;padding:6px 8px;border-radius:4px;cursor:pointer;font-size:13px}
.member-pick label:hover{background:#f6f8fb}
.member-pick input[type=checkbox]{width:15px;height:15px;cursor:pointer;accent-color:var(--brand)}

.import-result{background:#fafbfc;border:1px solid var(--line);border-radius:6px;padding:12px;font-size:13px;line-height:1.9;margin-top:12px}
.import-result .err{color:var(--danger);max-height:150px;overflow-y:auto}

.quiz-bar{display:flex;align-items:center;gap:10px;margin-bottom:8px}
.quiz-bar .no{width:22px;color:var(--t3);font-size:13px;flex:0 0 22px}
.quiz-bar .bar-track{flex:1;height:20px;background:#f0f2f5;border-radius:4px;overflow:hidden}
.quiz-bar .bar-fill{height:100%;background:var(--brand);border-radius:4px;transition:width .35s}
.quiz-bar .bar-fill.right{background:var(--ok)}
.quiz-bar .cnt{width:70px;text-align:right;font-size:13px;color:var(--t2);flex:0 0 70px}

.upload-zone{
  border:1.5px dashed var(--line);border-radius:8px;padding:22px;text-align:center;
  cursor:pointer;transition:.15s;background:#fafbfc;
}
.upload-zone:hover{border-color:var(--brand);background:var(--brand-light)}
.upload-zone b{display:block;font-size:14px;margin-bottom:4px}
.upload-zone span{font-size:12.5px;color:var(--t3)}
.upload-name{margin-top:10px;font-size:13px;color:var(--brand)}

.switch{display:inline-flex;align-items:center;gap:8px;cursor:pointer;font-size:13px}
.switch input{display:none}
.switch i{width:38px;height:20px;background:#dcdfe6;border-radius:10px;position:relative;transition:.2s;flex:0 0 38px}
.switch i::after{content:'';position:absolute;top:2px;left:2px;width:16px;height:16px;background:#fff;border-radius:50%;transition:.2s;box-shadow:0 1px 3px rgba(0,0,0,.2)}
.switch input:checked + i{background:var(--brand)}
.switch input:checked + i::after{transform:translateX(18px)}

.pager{display:flex;justify-content:flex-end;gap:8px;align-items:center;padding:14px 16px;font-size:13px;color:var(--t2)}

@media (max-width:900px){
  :root{--side:62px}
  .nav-text{display:none}
  .brand-info{display:none}
  .brand-logo{margin:0 auto}
  .nav-item{justify-content:center}
  .topbar-title{font-size:15px}
  .content{padding:14px 12px 24px}
}