:root{
  --bg:#F5F8FE; --bg2:#E7EFFB; --grid:#DBE6F7; --panel:#FFFFFF; --panel2:#EFF4FD; --border:#D8E3F4;
  --text:#14243D; --muted:#5C7291; --red:#E5484D; --green:#12915A; --gold:#B4790A;
  --gray:#93A2B7; --blue:#2563EB; --warn:#B45309;
  --soft-red:#FDECEC; --soft-green:#E8F8F0; --soft-gold:#FEF5E3; --soft-blue:#E3EDFF; --soft-gray:#F1F4F9;
  --shadow:0 6px 22px rgba(23,49,92,.08);
  --font-title:KaiTi,STKaiti,"Songti SC",SimSun,serif;
  --font-math:"Cambria Math","Latin Modern Math","Times New Roman",serif;
  --font-body:-apple-system,BlinkMacSystemFont,"PingFang SC","Microsoft YaHei",sans-serif;
}
*{box-sizing:border-box}
[hidden]{display:none!important}
html,body{margin:0;min-height:100%}
body{
  background:linear-gradient(180deg,#FAFCFF 0%,var(--bg) 28%,var(--bg2) 100%) fixed;
  color:var(--text); font-family:var(--font-body);
  display:flex; flex-direction:column; min-height:100vh; position:relative;
}
/* 背景层：照片 → 蒙层 → 坐标纸 → 水印 */
.bg-image{position:fixed;inset:0;z-index:0;pointer-events:none;display:none;
  background-size:cover;background-position:center;background-repeat:no-repeat}
body.has-photo .bg-image{display:block}
.bg-scrim{position:fixed;inset:0;z-index:0;pointer-events:none;display:none;
  background:linear-gradient(180deg,rgba(248,251,255,.86),rgba(238,245,254,.92))}
body.has-photo .bg-scrim{display:block}
body.has-photo .grid-bg,body.has-photo .watermark{display:none}
body.has-photo .panel,body.has-photo .card,body.has-photo .stu-card{
  background:rgba(255,255,255,.9);backdrop-filter:blur(6px)}
.grid-bg{position:fixed;inset:0;pointer-events:none;z-index:0;
  background-image:
    linear-gradient(rgba(37,99,235,.05) 1px,transparent 1px),
    linear-gradient(90deg,rgba(37,99,235,.05) 1px,transparent 1px),
    linear-gradient(rgba(37,99,235,.09) 1px,transparent 1px),
    linear-gradient(90deg,rgba(37,99,235,.09) 1px,transparent 1px);
  background-size:40px 40px,40px 40px,200px 200px,200px 200px;
}
.watermark{position:fixed;inset:0;pointer-events:none;z-index:0;font-family:var(--font-math);font-size:18vw;color:rgba(37,99,235,.045)}
.watermark span{position:absolute}
header.topbar,main,footer{position:relative;z-index:1}

/* 顶栏 */
.topbar{display:flex;align-items:center;gap:16px;padding:10px 20px;background:rgba(255,255,255,.88);
  backdrop-filter:blur(10px);border-bottom:1px solid var(--border);position:sticky;top:0;z-index:5;flex-wrap:wrap}
.brand{display:flex;align-items:center;gap:8px;font-family:var(--font-title);font-size:1.35rem;font-weight:700}
.brand small{color:var(--blue);background:var(--soft-blue);font-size:.7rem;border:1px solid var(--border);padding:1px 6px;border-radius:999px}
.brand-mark{color:var(--blue);font-family:var(--font-math)}
.tabs{display:flex;gap:6px;flex:1;flex-wrap:wrap}
.tab{background:var(--panel2);color:var(--muted);border:1px solid var(--border);border-radius:10px;
  padding:8px 16px;font-size:1rem;cursor:pointer;font-family:inherit;transition:.15s}
.tab:hover{border-color:var(--blue);color:var(--blue)}
.tab.active{background:var(--soft-blue);color:var(--blue);border-color:var(--blue);font-weight:700}
.tab .lock{font-size:.75rem}
.tab.unlocked .lock{display:none}
.topbar-right{display:flex;align-items:center;gap:10px}
.seg{display:flex;border:1px solid var(--border);border-radius:10px;overflow:hidden;background:var(--panel2)}
.seg button{background:transparent;color:var(--muted);border:0;padding:8px 14px;cursor:pointer;font-family:inherit;font-size:.95rem}
.seg button.active{background:var(--blue);color:#fff;font-weight:700}

/* 通用 */
.btn{background:var(--panel2);color:var(--muted);border:1px solid var(--border);border-radius:10px;
  padding:9px 15px;font-size:.95rem;cursor:pointer;font-family:inherit;transition:.15s;white-space:nowrap}
.btn:hover{border-color:var(--blue);color:var(--blue)}
.btn:active{transform:scale(.97)}
.btn.primary{background:var(--blue);color:#fff;border-color:var(--blue)}
.btn.primary:hover{background:#1D4ED8;color:#fff;border-color:#1D4ED8}
.btn.danger:hover{border-color:var(--red);color:var(--red);background:var(--soft-red)}
.btn.file{display:inline-block}
.btn:disabled{opacity:.5;cursor:not-allowed}
.btn:disabled:hover{border-color:var(--border);color:var(--muted)}
.answer-group{display:inline-flex;align-items:center;gap:10px;flex-wrap:wrap}
.multi-group{display:inline-flex;align-items:center;gap:10px;flex-wrap:wrap}
.multi-bar{display:inline-flex;align-items:center;gap:8px;flex-wrap:wrap}
.chip.selected{outline:3px solid var(--blue);outline-offset:2px;background:var(--soft-blue)!important;box-shadow:0 0 0 4px rgba(37,99,235,.18)}
body.multi-on .card[data-zone] .chip[data-stu]{cursor:pointer}
body.multi-on .card[data-zone] .chip[data-stu]:hover{outline:3px solid rgba(37,99,235,.55);outline-offset:2px}
.answer-info{font-size:.85rem;max-width:340px}
.view{display:none;padding:22px 26px 40px;max-width:1400px;width:100%;margin:0 auto;flex:1}
#view-screen{max-width:1900px}
.view.active{display:block}
.panel{background:var(--panel);border:1px solid var(--border);border-radius:14px;padding:18px;margin-bottom:18px;box-shadow:var(--shadow)}
.panel-head{display:flex;align-items:center;justify-content:space-between;margin-bottom:12px}
.panel-head h3{margin:0;font-size:1.05rem;color:var(--blue)}
.muted{color:var(--muted);font-size:.9rem}
.actions{display:flex;gap:10px;flex-wrap:wrap;margin-top:12px}
input,textarea{background:var(--panel);border:1px solid var(--border);border-radius:10px;color:var(--text);
  padding:9px 12px;font-family:inherit;font-size:1rem;outline:none}
input:focus,textarea:focus{border-color:var(--blue);box-shadow:0 0 0 3px rgba(37,99,235,.12)}
textarea{width:100%;resize:vertical;line-height:1.7}
label.field{display:flex;align-items:center;gap:8px;background:var(--panel);border:1px solid var(--border);border-radius:10px;padding:6px 12px}
label.field span{color:var(--blue);font-family:var(--font-math)}
label.field input{border:0;background:transparent;padding:4px 0;width:auto}
input[type=date]{color-scheme:light}
.footer{text-align:center;color:var(--muted);font-family:var(--font-title);padding:14px;font-size:.85rem}

/* 大屏 */
.screen-toolbar{display:flex;gap:10px;flex-wrap:wrap;align-items:center;margin-bottom:10px}
.screen-head{text-align:center;margin:2px 0 12px}
.screen-head h1{font-family:var(--font-title);font-size:clamp(1.6rem,3.4vw,2.6rem);margin:0 0 6px;color:#0F2A5C}
.subtitle{color:var(--muted);font-family:var(--font-math);font-size:clamp(1rem,1.6vw,1.3rem);margin:0}
.cards{display:grid;grid-template-columns:repeat(4,minmax(0,1fr));gap:12px;align-items:stretch}
@media (max-width:1150px){.cards{grid-template-columns:repeat(2,minmax(0,1fr))}}
.card{background:var(--panel);border:1px solid var(--border);border-radius:12px;padding:10px 12px;min-height:0;box-shadow:var(--shadow);display:flex;flex-direction:column;overflow:hidden}
.card h2{margin:0 0 8px;font-size:clamp(.95rem,1.25vw,1.3rem);display:flex;align-items:center;gap:8px;font-family:var(--font-title);flex:none}
.card h2 em{font-style:normal;font-size:.85em;opacity:.75;font-family:var(--font-math)}
.card-red{border-top:4px solid var(--red);background:linear-gradient(180deg,var(--soft-red),var(--panel) 55%)}
.card-red h2{color:var(--red)}
.card-green{border-top:4px solid var(--green);background:linear-gradient(180deg,var(--soft-green),var(--panel) 55%)}
.card-green h2{color:var(--green)}
.card-gold{border-top:4px solid var(--gold);background:linear-gradient(180deg,var(--soft-gold),var(--panel) 55%)}
.card-gold h2{color:var(--gold)}
.card-gray{border-top:4px solid var(--gray);background:linear-gradient(180deg,var(--soft-gray),var(--panel) 55%)}
.card-gray h2{color:var(--gray)}
body.has-photo .card-red{background:rgba(255,255,255,.9)}
body.has-photo .card-green{background:rgba(255,255,255,.9)}
body.has-photo .card-gold{background:rgba(255,255,255,.9)}
body.has-photo .card-gray{background:rgba(255,255,255,.9)}
.chips{display:flex;flex-wrap:wrap;gap:6px;align-content:flex-start;flex:1;min-height:0;overflow-y:auto;overflow-x:hidden;scrollbar-width:thin}
.chip{border-radius:999px;border:2px solid;padding:.18em .55em;font-weight:800;
  font-size:var(--chip-size,1.2rem);line-height:1.15;font-family:var(--font-title);background:#fff;
  transition:box-shadow .12s,border-color .12s,background .12s}
.chip[data-stu]{cursor:pointer;user-select:none}
.chip[draggable="true"]{cursor:grab}
.chip.dragging{opacity:.35}
.card[data-zone].drop-target{border-color:var(--blue);box-shadow:0 0 0 5px rgba(37,99,235,.18),var(--shadow);background:var(--soft-blue)}
.chip[data-stu]:hover{box-shadow:0 0 0 4px rgba(37,99,235,.2)}
.chip.red{border-color:var(--red);color:var(--red)}
.chip.green{border-color:var(--green);color:var(--green)}
.chip.gold{border-color:var(--gold);color:var(--gold)}
.chip.gray{border-color:var(--gray);color:var(--gray)}
.chip.small{font-size:var(--chip-size,1.2rem)}
.card h2{font-size:20px}
.empty{color:var(--gray);font-family:var(--font-math);font-size:calc(var(--chip-size,1.2rem) * 1.1)}
#view-screen{padding-bottom:10px}
#view-screen .autonote{position:fixed;left:0;right:0;bottom:2px;margin:0;text-align:center;color:var(--muted);opacity:.45;font-size:.72rem;z-index:2}
body.screen-view .footer{display:none}
.hw-note{max-width:1300px;margin:10px auto 0;background:linear-gradient(180deg,#F3F8FF,#FFFFFF);
  border:2px solid rgba(37,99,235,.25);border-left:12px solid var(--blue);border-radius:16px;
  padding:12px 22px;text-align:left;line-height:1.35;font-weight:700;
  font-size:clamp(1.5rem,2.4vw,2.4rem);color:#0F2A5C;box-shadow:0 10px 30px rgba(37,99,235,.14);
  white-space:pre-wrap;word-break:break-word}
.hw-note .note-tag{color:var(--blue);margin-right:.4em}
.hw-photo{margin-top:14px}
.hw-photo img{display:block;width:100%;max-height:42vh;object-fit:contain;background:#fff;
  border:1px solid var(--border);border-radius:12px}
body:fullscreen .hw-note{font-size:clamp(1.6rem,2.4vw,2.6rem);padding:10px 20px}
body:fullscreen .hw-photo img{max-height:46vh}

/* 积分 */
table.rank{width:100%;border-collapse:collapse;font-size:1.05rem}
table.rank th{color:var(--text);text-align:left;padding:10px 12px;border-bottom:2px solid var(--border);font-weight:600}
table.rank td{padding:10px 12px;border-bottom:1px solid var(--border)}
table.rank tr:nth-child(-n+4) td{background:rgba(37,99,235,.045)}
td.score{color:var(--gold);font-weight:800;font-family:var(--font-math);font-size:1.25rem}
td.rank-no{font-family:var(--font-math);color:var(--muted);width:60px}
.medal{font-size:1.2rem}

/* 录入 */
.entry-grid{display:grid;grid-template-columns:repeat(auto-fill,minmax(240px,1fr));gap:12px}
.stu-card{background:var(--panel);border:1px solid var(--border);border-radius:14px;padding:12px;box-shadow:var(--shadow)}
.stu-name{font-family:var(--font-title);font-size:1.25rem;font-weight:700;margin-bottom:10px;display:flex;justify-content:space-between;align-items:center}
.stu-btns{display:flex;gap:8px}
.stu-btns button{flex:1;border-radius:10px;border:1px solid var(--border);background:var(--panel2);color:var(--muted);
  padding:8px 4px;cursor:pointer;font-family:inherit;font-size:.9rem;transition:.15s}
.stu-btns button:active{transform:scale(.96)}
.b-s-sub{background:var(--soft-green);color:var(--green);border-color:var(--green);font-weight:600}
.b-s-miss{background:var(--soft-red);color:var(--red);border-color:var(--red);font-weight:600}
.b-c-wait{background:var(--soft-gold);color:var(--warn);border-color:var(--warn);font-weight:600}
.b-c-done{background:var(--soft-green);color:var(--green);border-color:var(--green);font-weight:600}
.b-e-on{background:var(--soft-gold);color:var(--gold);border-color:var(--gold);font-weight:700}

/* 班级编辑 */
.class-editor{display:flex;flex-direction:column;gap:10px}
.rep-name{min-width:120px;font-weight:600}
select{background:var(--panel);border:1px solid var(--border);border-radius:10px;color:var(--text);
  padding:9px 12px;font-family:inherit;font-size:1rem;outline:none}
select:focus{border-color:var(--blue);box-shadow:0 0 0 3px rgba(37,99,235,.12)}
.login-row{display:flex;gap:10px;margin:10px 0 0}
.login-row select{flex:1}
.class-row{display:flex;gap:10px;align-items:center}
.class-row input{flex:1}
.pw-row{display:flex;gap:10px;flex-wrap:wrap}
.pw-row input{flex:1;min-width:180px}

/* 外观（背景图） */
.bg-preview{width:100%;max-width:460px;aspect-ratio:16/9;border-radius:12px;border:1px dashed var(--border);
  background:var(--panel2) center/cover no-repeat;display:flex;align-items:center;justify-content:center;
  color:var(--muted);font-size:.9rem;margin-bottom:12px}
.bg-preview.set{border-style:solid}

/* toast / modal */
.toast{position:fixed;top:16px;right:16px;background:var(--soft-green);color:var(--green);border:1px solid var(--green);
  border-radius:10px;padding:10px 16px;opacity:0;transform:translateY(-8px);transition:.2s;pointer-events:none;z-index:50;box-shadow:var(--shadow)}
.toast.show{opacity:1;transform:none}
.toast.err{background:var(--soft-red);border-color:var(--red);color:var(--red)}
.modal{position:fixed;inset:0;background:rgba(16,32,60,.45);display:none;align-items:center;justify-content:center;z-index:60}
.modal.show{display:flex}
.modal-box{background:var(--panel);border:1px solid var(--border);border-radius:14px;padding:24px;width:min(400px,90vw);box-shadow:0 18px 50px rgba(15,42,92,.25)}
.modal-box h3{margin:0 0 6px;font-family:var(--font-title)}
.modal-box input{width:100%;margin:14px 0}
.modal-box .actions{justify-content:flex-end}

/* 全屏 */
body:fullscreen .grid-bg,body:fullscreen .watermark,body:fullscreen .footer,body:fullscreen .autonote{opacity:.15}
body:fullscreen .topbar{display:none}
body:fullscreen .view{padding:2vh 3vw;max-width:none}
body:fullscreen .screen-toolbar{opacity:0;height:0;overflow:hidden;margin:0}
body:fullscreen .cards{gap:14px}