:root{
  --bg:#f7f8fa;
  --panel:rgba(255,255,255,.92);
  --panel-solid:#ffffff;
  --border:rgba(0,0,0,.07);
  --border-strong:rgba(0,0,0,.12);
  --text:#0b0d10;
  --text-2:#515866;
  --muted:#868d9b;
  --brand:#0a84ff;
  --brand-2:#3d9dff;
  --brand-soft:#e9f2ff;
  --green:#30a46c;
  --green-soft:#e6f6ec;
  --red:#e5484d;
  --red-soft:#fdecec;
  --amber:#f2a11b;
  --amber-soft:#fff6e5;
  --purple:#8e4ec6;
  --purple-soft:#f5ebfd;
  --shadow-sm:0 1px 1.5px rgba(15,18,24,.04), 0 1px 2px rgba(15,18,24,.03);
  --shadow:0 2px 4px rgba(15,18,24,.04), 0 12px 32px -12px rgba(15,18,24,.14);
  --shadow-lg:0 24px 60px -20px rgba(15,18,24,.28);
  --radius:16px;
  --radius-sm:10px;
  --radius-lg:22px;
  --blur:saturate(180%) blur(22px);
  --ease:cubic-bezier(.32,.72,.22,1);

  color-scheme: light;   /* 强制浅色：原生控件（滚动条、日期选择器、下拉箭头）也走浅色 */
}

*{box-sizing:border-box;-webkit-tap-highlight-color:transparent;}
html,body{height:100%;}
body{
  margin:0;
  font-family:-apple-system,BlinkMacSystemFont,"SF Pro Text","SF Pro Display",
    "Helvetica Neue","PingFang SC","Hiragino Sans GB","Microsoft YaHei",
    Roboto,Segoe UI,Arial,sans-serif;
  background:var(--bg);
  color:var(--text);
  -webkit-font-smoothing:antialiased;
  font-size:14px;
  letter-spacing:-0.005em;
  line-height:1.5;
}
.hidden{display:none !important;}
button{font-family:inherit;cursor:pointer;letter-spacing:-0.005em;}
input,select,textarea{font-family:inherit;letter-spacing:-0.005em;}

/* ============ Login ============ */
.login-wrap{
  min-height:100vh;display:flex;align-items:center;justify-content:center;padding:24px;
  background:
    radial-gradient(1200px 600px at 15% -10%, #e9f2ff 0%, transparent 55%),
    radial-gradient(1000px 600px at 110% 110%, #e6f6ec 0%, transparent 55%),
    #f7f8fa;
}
.login-card{
  width:400px;background:var(--panel);backdrop-filter:var(--blur);
  -webkit-backdrop-filter:var(--blur);
  border-radius:var(--radius-lg);padding:38px 34px 30px;
  border:1px solid rgba(255,255,255,.75);
  box-shadow:var(--shadow-lg);
  animation:rise .35s var(--ease);
}
@keyframes rise{from{opacity:0;transform:translateY(12px) scale(.98)}to{opacity:1;transform:none}}
.brand{display:flex;align-items:center;gap:14px;margin-bottom:30px;}
.brand h1{font-size:18px;margin:0 0 4px;letter-spacing:-.02em;font-weight:650;}
.brand p{margin:0;color:var(--muted);font-size:12px;}
.brand-icon{
  width:48px;height:48px;border-radius:14px;display:grid;place-items:center;color:#fff;
  background:linear-gradient(150deg,#3d9dff,#0a84ff);
  box-shadow:0 10px 22px -10px rgba(10,132,255,.75), inset 0 1px 0 rgba(255,255,255,.4);
}
.brand-icon.small{width:32px;height:32px;border-radius:10px;}
.brand-icon svg{width:22px;height:22px;}
.brand-icon.small svg{width:16px;height:16px;}
.field{margin-bottom:16px;}
.field label{display:block;font-size:12.5px;color:var(--text-2);margin-bottom:6px;font-weight:520;}
.field input,.field select,.field textarea{
  width:100%;padding:11px 13px;border:1px solid var(--border-strong);border-radius:11px;
  background:rgba(255,255,255,.85);font-size:14px;outline:none;transition:.2s var(--ease);color:var(--text);
}
.field input:focus,.field select:focus,.field textarea:focus{
  border-color:var(--brand);background:#fff;
  box-shadow:0 0 0 4px rgba(10,132,255,.14);
}
.login-tip{margin-top:16px;font-size:12px;color:var(--muted);text-align:center;line-height:1.8;}
.login-tip code{
  background:rgba(0,0,0,.05);padding:2px 7px;border-radius:6px;
  color:var(--text-2);font-size:11.5px;font-family:ui-monospace,Menlo,monospace;
}

/* ============ Layout ============ */
.app{display:flex;min-height:100vh;}
.sidebar{
  width:240px;position:sticky;top:0;height:100vh;
  background:var(--panel);backdrop-filter:var(--blur);-webkit-backdrop-filter:var(--blur);
  border-right:1px solid var(--border);
  display:flex;flex-direction:column;padding:20px 14px 16px;
  z-index:30;
}
.side-brand{
  display:flex;align-items:center;gap:10px;font-weight:650;font-size:14px;
  padding:2px 8px 20px;letter-spacing:-.015em;
}
.nav{display:flex;flex-direction:column;gap:1px;flex:1;overflow-y:auto;padding:0 2px;}
.nav-item{
  display:flex;align-items:center;gap:11px;padding:9px 12px;border-radius:10px;
  color:var(--text-2);font-size:13.5px;font-weight:520;border:none;background:none;
  text-align:left;width:100%;transition:all .18s var(--ease);
}
.nav-item:hover{background:rgba(0,0,0,.04);color:var(--text);}
.nav-item.active{
  background:var(--brand);color:#fff;font-weight:600;
  box-shadow:0 6px 14px -8px rgba(10,132,255,.8);
}
.nav-item.active svg{color:#fff;}
.nav-item svg{width:17px;height:17px;transition:.18s;}
.side-foot{border-top:1px solid var(--border);padding-top:14px;margin-top:10px;}
.user-chip{display:flex;align-items:center;gap:10px;padding:6px 6px 12px;}
.avatar{
  width:34px;height:34px;border-radius:50%;display:grid;place-items:center;color:#fff;
  background:linear-gradient(140deg,#3d9dff,#0a84ff);font-weight:600;font-size:13px;
  box-shadow:0 6px 14px -8px rgba(10,132,255,.9);
}
.user-info{line-height:1.35;overflow:hidden;}
.user-info>div:first-child{font-size:13px;font-weight:600;white-space:nowrap;text-overflow:ellipsis;overflow:hidden;}
.muted{color:var(--muted);font-size:11.5px;}

.main{flex:1;min-width:0;display:flex;flex-direction:column;}
.topbar{
  height:62px;display:flex;align-items:center;justify-content:space-between;
  padding:0 26px;position:sticky;top:0;z-index:20;
  background:rgba(247,248,250,.78);backdrop-filter:var(--blur);-webkit-backdrop-filter:var(--blur);
  border-bottom:1px solid var(--border);
}
.page-title{font-size:17px;font-weight:650;letter-spacing:-.02em;}
.top-actions{display:flex;gap:8px;}
.badge{
  font-size:12px;padding:5px 12px;border-radius:20px;background:rgba(0,0,0,.05);color:var(--text-2);
  font-weight:520;display:inline-flex;align-items:center;gap:5px;letter-spacing:-.005em;
}
.badge svg{width:13px;height:13px;}
.badge.ok{background:var(--green-soft);color:var(--green);}
.badge.warn{background:var(--amber-soft);color:#a15c00;}
.badge.err{background:var(--red-soft);color:var(--red);}
.content{padding:22px 26px 60px;}

/* ============ Card ============ */
.card{
  background:var(--panel-solid);border:1px solid var(--border);border-radius:var(--radius);
  box-shadow:var(--shadow-sm);padding:18px 18px 16px;margin-bottom:18px;
  transition:box-shadow .25s var(--ease);
}
.card:hover{box-shadow:var(--shadow);}
.card-head{display:flex;align-items:center;justify-content:space-between;margin-bottom:14px;gap:10px;flex-wrap:wrap;}
.card-title{font-size:14.5px;font-weight:640;display:flex;align-items:center;gap:8px;letter-spacing:-.015em;}
.card-title svg{width:16px;height:16px;color:var(--brand);}
.card-sub{font-size:12.5px;color:var(--muted);}
.grid{display:grid;gap:16px;}
.grid.c2{grid-template-columns:repeat(2,minmax(0,1fr));}
.grid.c3{grid-template-columns:repeat(3,minmax(0,1fr));}
.grid.c4{grid-template-columns:repeat(4,minmax(0,1fr));}
@media (max-width:1100px){.grid.c4{grid-template-columns:repeat(2,1fr);}.grid.c3{grid-template-columns:repeat(2,1fr);}}
@media (max-width:760px){
  .grid.c2,.grid.c3,.grid.c4{grid-template-columns:1fr;}
  .sidebar{display:none;}
}

.stat{
  padding:16px 18px;border-radius:14px;background:var(--panel-solid);
  border:1px solid var(--border);box-shadow:var(--shadow-sm);
  transition:transform .25s var(--ease), box-shadow .25s var(--ease);
}
.stat:hover{transform:translateY(-2px);box-shadow:var(--shadow);}
.stat .label{font-size:12px;color:var(--muted);margin-bottom:8px;display:flex;align-items:center;gap:6px;font-weight:520;}
.stat .label svg{width:14px;height:14px;}
.stat .value{font-size:27px;font-weight:680;letter-spacing:-.03em;}
.stat .value small{font-size:13px;color:var(--muted);font-weight:500;margin-left:4px;letter-spacing:0;}

/* ============ Buttons ============ */
.btn{
  display:inline-flex;align-items:center;gap:7px;padding:9px 15px;border-radius:11px;
  border:1px solid var(--border-strong);background:#fff;color:var(--text);font-size:13px;font-weight:540;
  transition:all .18s var(--ease);white-space:nowrap;
}
.btn:hover{background:#f4f5f7;border-color:var(--border-strong);}
.btn:active{transform:scale(.97);}
.btn svg{width:15px;height:15px;}
.btn.primary{
  background:var(--brand);border-color:var(--brand);color:#fff;
  box-shadow:0 1px 2px rgba(10,132,255,.25), inset 0 1px 0 rgba(255,255,255,.25);
}
.btn.primary:hover{background:#0a76e8;border-color:#0a76e8;}
.btn.danger{color:var(--red);border-color:#f3c5c6;background:#fff;}
.btn.danger:hover{background:var(--red-soft);}
.btn.ghost{border-color:transparent;background:transparent;color:var(--text-2);}
.btn.ghost:hover{background:rgba(0,0,0,.05);color:var(--text);}
.btn.block{width:100%;justify-content:center;}
.btn.sm{padding:6px 12px;font-size:12.5px;border-radius:9px;}
.btn.sm svg{width:13px;height:13px;}
.btn:disabled{opacity:.5;cursor:not-allowed;}
.icon-btn{
  width:32px;height:32px;display:inline-grid;place-items:center;border-radius:9px;
  border:none;background:transparent;color:var(--text-2);transition:.18s var(--ease);
}
.icon-btn:hover{background:rgba(0,0,0,.06);color:var(--text);}
.icon-btn:active{transform:scale(.92);}
.icon-btn svg{width:16px;height:16px;}

/* ============ Table ============ */
.table-wrap{border:1px solid var(--border);border-radius:14px;overflow:hidden;background:#fff;box-shadow:var(--shadow-sm);}
.tbl{width:100%;border-collapse:collapse;font-size:13px;}
.tbl thead th{
  background:#fafbfc;text-align:left;padding:11px 14px;font-weight:600;color:var(--text-2);
  font-size:12px;letter-spacing:.01em;border-bottom:1px solid var(--border);white-space:nowrap;
}
.tbl tbody td{padding:12px 14px;border-bottom:1px solid #f2f3f5;vertical-align:middle;letter-spacing:-.005em;}
.tbl tbody tr:last-child td{border-bottom:none;}
.tbl tbody tr{transition:background .15s;}
.tbl tbody tr:hover{background:#fafbfc;}
.tbl .empty{text-align:center;padding:40px;color:var(--muted);}

/* ============ Tags ============ */
.tag{
  display:inline-flex;align-items:center;gap:4px;font-size:11.5px;padding:3px 10px;
  border-radius:20px;background:rgba(0,0,0,.05);color:var(--text-2);font-weight:550;
  margin:1px 3px 1px 0;letter-spacing:0;
}
.tag.blue{background:var(--brand-soft);color:var(--brand);}
.tag.green{background:var(--green-soft);color:var(--green);}
.tag.red{background:var(--red-soft);color:var(--red);}
.tag.amber{background:var(--amber-soft);color:#a15c00;}
.tag.purple{background:var(--purple-soft);color:var(--purple);}

/* ============ Filter ============ */
.filter{
  display:flex;flex-wrap:wrap;gap:10px;align-items:flex-end;
  padding:14px;border-radius:14px;background:#fafbfc;border:1px solid var(--border);margin-bottom:14px;
}
.filter .field{margin:0;min-width:130px;}
.filter .field.grow{flex:1;min-width:180px;}
.filter input,.filter select{padding:8px 11px;font-size:13px;background:#fff;}

/* ============ Chips ============ */
.chip-list{display:flex;flex-wrap:wrap;gap:8px;margin-top:10px;min-height:34px;}
.chip{
  display:inline-flex;align-items:center;gap:7px;padding:6px 12px;border-radius:20px;
  background:rgba(0,0,0,.05);font-size:12.5px;font-weight:520;
}
.chip .x{cursor:pointer;color:var(--muted);display:grid;place-items:center;width:16px;height:16px;border-radius:50%;}
.chip .x:hover{background:rgba(0,0,0,.1);color:var(--text);}
.chip svg{width:12px;height:12px;}

/* ============ Segmented ============ */
.seg{display:inline-flex;background:rgba(0,0,0,.05);border-radius:10px;padding:2px;}
.seg button{
  border:none;background:transparent;padding:5px 12px;font-size:12px;color:var(--text-2);
  border-radius:8px;transition:all .18s var(--ease);font-weight:520;
}
.seg button.on{background:#fff;color:var(--text);font-weight:600;box-shadow:0 1px 2px rgba(0,0,0,.08);}
.seg button.on.absent{background:var(--red);color:#fff;box-shadow:none;}
.seg button.on.leave{background:#f2a11b;color:#fff;box-shadow:none;}
.seg button.on.present{background:var(--green);color:#fff;box-shadow:none;}

/* ============ Modal ============ */
.modal-mask{
  position:fixed;inset:0;background:rgba(15,18,24,.35);backdrop-filter:blur(6px);-webkit-backdrop-filter:blur(6px);
  display:flex;align-items:center;justify-content:center;z-index:100;padding:20px;
  animation:fade .2s var(--ease);
}
@keyframes fade{from{opacity:0}to{opacity:1}}
.modal{
  background:#fff;border-radius:20px;width:min(680px,100%);max-height:88vh;
  display:flex;flex-direction:column;box-shadow:var(--shadow-lg);
  animation:pop .28s var(--ease);
}
@keyframes pop{from{transform:scale(.96) translateY(8px);opacity:0}to{transform:none;opacity:1}}
.modal-head{
  padding:16px 20px;border-bottom:1px solid var(--border);display:flex;
  align-items:center;justify-content:space-between;font-weight:640;font-size:15px;letter-spacing:-.015em;
}
.modal-body{padding:20px;overflow-y:auto;}
.modal-foot{padding:14px 20px;border-top:1px solid var(--border);display:flex;justify-content:flex-end;gap:9px;}

/* ============ Toast ============ */
.toast{
  position:fixed;top:22px;left:50%;transform:translateX(-50%);
  padding:11px 20px;border-radius:12px;background:rgba(11,13,16,.94);color:#fff;font-size:13px;
  z-index:9999;box-shadow:var(--shadow-lg);font-weight:520;letter-spacing:-.005em;
  animation:slideDown .26s var(--ease);backdrop-filter:blur(12px);-webkit-backdrop-filter:blur(12px);
}
@keyframes slideDown{from{opacity:0;transform:translate(-50%,-12px)}to{opacity:1;transform:translate(-50%,0)}}
.toast.ok{background:rgba(48,164,108,.96);}
.toast.err{background:rgba(229,72,77,.96);}

/* ============ Search ============ */
.search{position:relative;display:flex;align-items:center;}
.search svg{position:absolute;left:11px;width:15px;height:15px;color:var(--muted);pointer-events:none;}
.search input{padding-left:33px !important;}

/* ============ Student Picker ============ */
.picker{display:grid;grid-template-columns:1fr 1fr;gap:14px;}
@media (max-width:900px){.picker{grid-template-columns:1fr;}}
.picker-list{
  border:1px solid var(--border);border-radius:14px;max-height:420px;overflow-y:auto;background:#fff;
  box-shadow:var(--shadow-sm);
}
.picker-item{
  display:flex;align-items:center;gap:10px;padding:10px 13px;border-bottom:1px solid #f2f3f5;
  transition:background .15s;font-size:13px;
}
.picker-item:last-child{border-bottom:none;}
.picker-item:hover{background:#fafbfc;}
.picker-item input[type=checkbox]{width:15px;height:15px;accent-color:var(--brand);cursor:pointer;}
.picker-item .meta{color:var(--muted);font-size:11.5px;margin-left:auto;}

/* ============ Tabs ============ */
.tabs{display:flex;gap:2px;border-bottom:1px solid var(--border);margin-bottom:16px;overflow-x:auto;}
.tab{
  padding:10px 15px;font-size:13.5px;color:var(--text-2);border:none;background:none;
  border-bottom:2px solid transparent;font-weight:520;white-space:nowrap;transition:.18s;
  margin-bottom:-1px;
}
.tab:hover{color:var(--text);}
.tab.active{color:var(--brand);border-bottom-color:var(--brand);font-weight:620;}

/* scrollbar */
::-webkit-scrollbar{width:9px;height:9px;}
::-webkit-scrollbar-thumb{background:rgba(0,0,0,.16);border-radius:6px;border:2px solid transparent;background-clip:content-box;}
::-webkit-scrollbar-thumb:hover{background:rgba(0,0,0,.26);background-clip:content-box;}
::-webkit-scrollbar-track{background:transparent;}

/* empty */
.empty-state{text-align:center;padding:56px 20px;color:var(--muted);}
.empty-state svg{width:38px;height:38px;margin-bottom:12px;opacity:.32;}
.empty-state p{margin:0;font-size:13.5px;}

/* bar */
.bar{height:8px;border-radius:6px;background:rgba(0,0,0,.05);overflow:hidden;}
.bar>i{display:block;height:100%;background:linear-gradient(90deg,#3d9dff,#0a84ff);border-radius:6px;
  transition:width .4s var(--ease);}

/* page section title */
.page-section-title{
  font-size:13px;font-weight:620;color:var(--text-2);margin:4px 0 8px;letter-spacing:-.005em;
}

/* ============ 班级预览 ============ */
.cls-head:hover { background: #f5f8fc; }
.cls-head .cls-arrow { transition: transform .2s var(--ease); }
.cls-row.open .cls-head { background: var(--brand-soft); }
.cls-row.open .cls-head .cls-arrow { transform: rotate(180deg); }