:root{
  --bg:#f5f6f8; --card:#ffffff; --line:#e6e8ec; --text:#1f2430; --muted:#7a8290;
  --primary:#2b5ce6; --primary-weak:#e8eeff; --green:#18a058; --green-weak:#e6f7ee;
  --amber:#e69a00; --amber-weak:#fdf3dc; --red:#d9534f; --red-weak:#fbe9e9;
  --radius:14px; --shadow:0 1px 3px rgba(16,24,40,.06),0 1px 2px rgba(16,24,40,.04);
}
*{box-sizing:border-box}
html,body{margin:0;padding:0}
body{background:var(--bg);color:var(--text);font-family:-apple-system,"Segoe UI","PingFang SC","Microsoft YaHei",sans-serif;font-size:14px;line-height:1.6}
button{font-family:inherit;cursor:pointer}
input,textarea,select{font-family:inherit;font-size:14px;color:var(--text);background:#fff;border:1px solid var(--line);border-radius:8px;padding:8px 10px;outline:none;width:100%}
input:focus,textarea:focus,select:focus{border-color:var(--primary);box-shadow:0 0 0 3px var(--primary-weak)}
textarea{resize:vertical;min-height:72px}
label{font-size:13px;color:var(--muted);display:block;margin:12px 0 4px}
label .opt{color:#b3bac4;font-weight:400;font-size:12px}
label .req{color:var(--red);font-weight:600}
.btn{display:inline-flex;align-items:center;gap:6px;border:none;border-radius:8px;padding:8px 14px;font-size:14px;font-weight:500;background:var(--primary);color:#fff;transition:.15s}
.btn:hover{opacity:.9}
.btn.ghost{background:#fff;color:var(--text);border:1px solid var(--line)}
.btn.ghost:hover{border-color:var(--primary);color:var(--primary)}
.btn.danger{background:var(--red-weak);color:var(--red)}
.btn.sm{padding:5px 10px;font-size:13px}
.btn.block{width:100%;justify-content:center}
.hidden{display:none !important}

/* 登录 */
#auth{min-height:100vh;display:flex;align-items:center;justify-content:center;padding:24px}
.auth-card{width:380px;background:var(--card);border:1px solid var(--line);border-radius:16px;padding:32px;box-shadow:var(--shadow)}
.auth-card h1{font-size:20px;margin:0 0 4px}
.auth-card .sub{color:var(--muted);font-size:13px;margin:0 0 24px}
.hint{font-size:12px;color:var(--muted);margin-top:6px}
.msg{font-size:13px;border-radius:8px;padding:8px 12px;margin-top:12px;display:none}
.msg.ok{display:block;background:var(--green-weak);color:var(--green)}
.msg.err{display:block;background:var(--red-weak);color:var(--red)}

/* 布局 */
#app{display:flex;height:100vh}
aside{width:280px;background:var(--card);border-right:1px solid var(--line);display:flex;flex-direction:column;flex-shrink:0}
.aside-head{padding:16px 18px;border-bottom:1px solid var(--line)}
.aside-head h1{font-size:16px;margin:0}
.aside-head .sub{font-size:12px;color:var(--muted);margin-top:2px}
.student-list{flex:1;overflow-y:auto;padding:12px}
.stu-item{padding:12px;border-radius:10px;cursor:pointer;border:1px solid transparent;margin-bottom:6px;transition:.12s}
.stu-item:hover{background:var(--bg)}
.stu-item.active{background:var(--primary-weak);border-color:var(--primary)}
.stu-item .name{font-weight:600;font-size:15px}
.stu-item .meta{font-size:12px;color:var(--muted);margin-top:2px}
.aside-foot{padding:12px;border-top:1px solid var(--line);display:flex;gap:8px}
.aside-foot .btn{flex:1;justify-content:center}
.user-row{display:flex;align-items:center;gap:8px;padding:10px 18px;border-top:1px solid var(--line);font-size:12px;color:var(--muted)}
.user-row .email{flex:1;overflow:hidden;text-overflow:ellipsis;white-space:nowrap}

main{flex:1;overflow-y:auto;padding:24px 28px}
.topbar{display:flex;align-items:center;justify-content:space-between;margin-bottom:18px}
.topbar h2{font-size:20px;margin:0}
.topbar .actions{display:flex;gap:8px}
.tabs{display:flex;gap:6px;margin-bottom:20px;border-bottom:1px solid var(--line);flex-wrap:wrap}
.tab{padding:8px 16px;font-size:14px;color:var(--muted);cursor:pointer;border-bottom:2px solid transparent;background:none;border-top:none;border-left:none;border-right:none}
.tab.active{color:var(--primary);border-bottom-color:var(--primary);font-weight:600}
.tab:hover{color:var(--primary)}

.grid{display:grid;gap:14px}
.grid.cols-2{grid-template-columns:1fr 1fr}
.grid.cols-3{grid-template-columns:repeat(3,1fr)}
@media(max-width:1000px){.grid.cols-3{grid-template-columns:1fr 1fr}.grid.cols-2{grid-template-columns:1fr}}
.card{background:var(--card);border:1px solid var(--line);border-radius:var(--radius);padding:18px;box-shadow:var(--shadow)}
.card h3{font-size:15px;margin:0 0 12px;display:flex;align-items:center;justify-content:space-between}
.card h3 .btn{margin-left:auto}
.kv{display:grid;grid-template-columns:repeat(auto-fill,minmax(160px,1fr));gap:10px 18px}
.kv .k{font-size:12px;color:var(--muted)}
.kv .v{font-size:14px;font-weight:500;word-break:break-all}
.tag{display:inline-block;font-size:12px;padding:2px 9px;border-radius:999px;font-weight:500}
.tag.blue{background:var(--primary-weak);color:var(--primary)}
.tag.green{background:var(--green-weak);color:var(--green)}
.tag.amber{background:var(--amber-weak);color:var(--amber)}
.tag.gray{background:#eef0f3;color:var(--muted)}
.chips{display:flex;flex-wrap:wrap;gap:8px;margin-top:4px}
.chip{display:inline-flex;align-items:center;gap:6px;padding:6px 12px;border:1px solid var(--line);border-radius:8px;cursor:pointer;font-size:13px;transition:.12s;user-select:none}
.chip:hover{border-color:var(--primary)}
.chip input{width:auto;margin:0;accent-color:var(--primary)}
.chip.on{border-color:var(--primary);background:var(--primary-weak);color:var(--primary);font-weight:500}

/* 表格 */
table{width:100%;border-collapse:collapse;font-size:13px}
th,td{padding:9px 10px;text-align:left;border-bottom:1px solid var(--line)}
th{color:var(--muted);font-weight:500;font-size:12px;background:#fafbfc}
tr:hover td{background:#fafbfc}
.row-actions{display:flex;gap:6px;justify-content:flex-end}

/* 时间轴 */
.timeline{position:relative;padding-left:22px}
.timeline:before{content:"";position:absolute;left:7px;top:4px;bottom:4px;width:2px;background:var(--line)}
.tl-item{position:relative;padding:0 0 18px 6px}
.tl-item:before{content:"";position:absolute;left:-21px;top:6px;width:10px;height:10px;border-radius:50%;background:var(--primary);border:2px solid #fff;box-shadow:0 0 0 1px var(--primary)}
.tl-item.done:before{background:var(--green);box-shadow:0 0 0 1px var(--green)}
.tl-item.doing:before{background:var(--amber);box-shadow:0 0 0 1px var(--amber)}
.tl-item .tl-title{font-weight:600}
.tl-item .tl-date{font-size:12px;color:var(--muted)}
.tl-item .tl-note{font-size:13px;color:var(--muted);margin-top:3px}

/* 表单 */
.form-row{display:grid;gap:12px}
.form-row.c2{grid-template-columns:1fr 1fr}
.form-row.c3{grid-template-columns:1fr 1fr 1fr}
@media(max-width:760px){.form-row.c2,.form-row.c3{grid-template-columns:1fr}}
.modal-mask{position:fixed;inset:0;background:rgba(15,20,30,.5);display:flex;align-items:flex-start;justify-content:center;z-index:50;overflow-y:auto;padding:32px 16px}
.modal{background:#fff;border-radius:16px;width:760px;max-width:100%;padding:24px;box-shadow:0 10px 40px rgba(0,0,0,.2)}
.modal h3{margin:0 0 4px;font-size:18px}
.modal .sub{color:var(--muted);font-size:13px;margin-bottom:16px}
.modal-foot{display:flex;justify-content:flex-end;gap:8px;margin-top:20px}
.chart-box{position:relative;height:260px}
.sec-title{font-size:14px;font-weight:600;margin:16px 0 8px;padding-left:10px;border-left:3px solid var(--primary)}
.empty{color:var(--muted);text-align:center;padding:32px 0;font-size:13px}

/* 报告/打印 */
#print-area{display:none}
@media print{
  body *{visibility:hidden}
  #print-area,#print-area *{visibility:visible}
  #print-area{display:block;position:absolute;left:0;top:0;width:100%;padding:0;color:#000}
  .report-head{border-bottom:2px solid #000;padding-bottom:12px;margin-bottom:16px}
  .report-head h1{font-size:22px;margin:0}
  .report-head .sub{font-size:13px;color:#444;margin-top:4px}
  .report-block{margin:18px 0}
  .report-block h2{font-size:15px;border-left:4px solid #000;padding-left:8px;margin:0 0 8px}
  .report-block p{font-size:13px;margin:4px 0;white-space:pre-wrap}
  .report-block table{font-size:12px}
  .report-block th,.report-block td{border:1px solid #999;padding:5px 8px}
}