*{box-sizing:border-box;margin:0;padding:0}
body{font-family:-apple-system,"PingFang SC","Microsoft YaHei",sans-serif;background:#f4f6f5;color:#1f2d2a;line-height:1.6}
header{background:#fff;border-bottom:1px solid #dce5df;padding:16px 20px;position:sticky;top:0;z-index:10}
header h1{font-size:20px;margin-bottom:10px}
nav{display:flex;gap:8px}
.tab{padding:8px 16px;border:1px solid #cfdcd4;background:#f0f4f1;border-radius:20px;cursor:pointer;font-size:14px}
.tab.active{background:#197565;color:#fff;border-color:#197565}
main{max-width:1100px;margin:0 auto;padding:20px}
.toolbar{display:flex;gap:10px;align-items:center;flex-wrap:wrap;margin-bottom:16px}
.btn{display:inline-block;padding:9px 14px;border:1px solid #cfdcd4;background:#fff;border-radius:8px;cursor:pointer;font-size:14px}
.btn.primary{background:#197565;color:#fff;border-color:#197565}
.btn.danger{background:#fee2e2;color:#b91c1c;border-color:#fecaca}
.chk{font-size:14px;display:flex;align-items:center;gap:6px}
#subjectSel,#newTopicTitle{padding:8px;border:1px solid #cfdcd4;border-radius:8px;font-size:14px}
.hw-card{background:#fff;border:1px solid #dce5df;border-radius:12px;padding:14px;margin-bottom:14px}
.hw-card h3{font-size:15px;margin-bottom:10px;display:flex;justify-content:space-between;align-items:center}
.q-grid{display:grid;grid-template-columns:repeat(auto-fill,minmax(220px,1fr));gap:10px}
.q-card{border:1px solid #e1e9e2;border-radius:10px;overflow:hidden;cursor:zoom-in;background:#fff}
.q-card.wrong{border-color:#f9a8d4;background:#fdf2f8}
.q-card img{width:100%;display:block}
.q-card .q-foot{padding:6px 8px;font-size:12px;display:flex;justify-content:space-between;align-items:center}
.tag{background:#e4f3eb;color:#197565;padding:2px 8px;border-radius:10px;font-size:12px}
.tag.wrong{background:#fce7f3;color:#9d174d}
.topic-card{background:#fff;border:1px solid #dce5df;border-radius:12px;padding:14px;margin-bottom:12px}
.topic-card h3{font-size:15px;margin-bottom:8px}
.topic-imgs{display:grid;grid-template-columns:repeat(auto-fill,minmax(200px,1fr));gap:8px}
.topic-imgs img{width:100%;border-radius:8px;cursor:zoom-in}
.empty{padding:30px;text-align:center;color:#8a9a93;background:#fff;border:1px dashed #d0dcd4;border-radius:12px}
#imgDialog{border:0;border-radius:12px;padding:10px;background:#fff;max-width:95vw;max-height:95vh}
#imgDialog::backdrop{background:#000a}
#imgDialog img{max-width:90vw;max-height:85vh;display:block;margin:0 auto 10px}
#imgDialog button{display:block;margin:0 auto}
progress{width:100%;height:6px}

[hidden]{display:none!important}
.site-header{display:flex;align-items:center;justify-content:space-between;gap:16px}
.site-header h1{margin:0;white-space:nowrap;flex-shrink:0}
.site-header nav{flex-wrap:nowrap;white-space:nowrap}
a.btn{text-decoration:none;color:inherit}a.btn.primary{color:#fff}
@media(max-width:600px){.site-header{padding:12px 10px;gap:6px}.site-header h1{font-size:16px}.site-header nav{gap:4px}.site-header .tab{font-size:12px;padding:7px 8px}}
@media(max-width:350px){.site-header h1{font-size:14px}.site-header .tab{padding:6px;font-size:11px}}
.manage-heading{justify-content:space-between}.manage-heading h2{font-size:20px}.new-form{display:grid;gap:14px;min-width:min(360px,80vw)}.new-form label{display:grid;gap:6px}.new-form input,.new-form select{padding:10px;border:1px solid #cfdcd4;border-radius:8px;font:inherit}#newDialog{border:0;border-radius:14px;padding:24px;margin:auto;max-width:94vw}#newDialog::backdrop{background:#0008}#newError{color:#b91c1c}.section-title{margin:20px 0 12px}.source-pages{margin-top:20px}.source-pages summary{cursor:pointer;margin-bottom:12px}.source-pages img{width:100%;cursor:zoom-in}.hw-card h3{gap:10px;flex-wrap:wrap}.hw-card p{color:#65766c}#hwDetail .q-grid{margin-bottom:18px}