:root{
  --bg:#f5f6f8; --surface:#ffffff; --ink:#1c2128; --ink-2:#5b6370; --ink-3:#8a909c;
  --line:#e4e7ec; --line-2:#d3d8e0;
  --brand:#4f46e5; --brand-2:#4338ca; --brand-tint:#eef2ff;
  --ok:#0f7b46; --ok-tint:#e7f6ee; --warn:#9a6b00; --warn-tint:#fdf2d8;
  --danger:#b42318; --danger-tint:#fdecea;
  --radius:8px;
  --font:-apple-system,BlinkMacSystemFont,"Segoe UI",Roboto,Helvetica,Arial,sans-serif;
}
*{box-sizing:border-box}
html,body{margin:0}
body{font-family:var(--font);color:var(--ink);background:var(--bg);font-size:15px;line-height:1.5}
a{color:var(--brand-2);text-decoration:none}
a:hover{text-decoration:underline}
h1,h2{font-weight:600;margin:0}
h2{font-size:17px}
code{font-family:ui-monospace,SFMono-Regular,Menlo,Consolas,monospace}
:focus-visible{outline:2px solid var(--brand);outline-offset:1px}

/* Layout */
.app{display:flex;min-height:100vh}
.sidebar{width:224px;flex:none;background:var(--surface);border-right:1px solid var(--line);padding:16px 12px}
.brand{display:flex;align-items:center;gap:8px;font-weight:600;font-size:15px;padding:4px 8px 16px}
.brand-mark{display:inline-flex;align-items:center;justify-content:center;width:26px;height:26px;background:var(--brand);color:#fff;border-radius:6px;font-size:12px;font-weight:700}
nav{display:flex;flex-direction:column;gap:2px}
.nav-link{display:flex;align-items:center;gap:10px;padding:8px 10px;border-radius:var(--radius);color:var(--ink-2);font-size:14px}
.nav-link:hover{background:var(--bg);text-decoration:none}
.nav-link.is-active{background:var(--brand-tint);color:var(--brand-2);font-weight:500}
.nav-link.is-disabled{color:var(--ink-3);cursor:default}
.nav-link.is-disabled:hover{background:transparent}
.nav-ico{width:18px;height:18px;flex:none}
.soon{margin-left:auto;font-style:normal;font-size:11px;color:var(--ink-3);background:var(--bg);padding:1px 6px;border-radius:20px}
.nav-divider{margin:12px 10px 4px;font-size:11px;letter-spacing:.02em;color:var(--ink-3)}

.main{flex:1;min-width:0;display:flex;flex-direction:column}
.topbar{display:flex;align-items:center;justify-content:space-between;padding:14px 24px;background:var(--surface);border-bottom:1px solid var(--line)}
.page-title{font-size:18px}
.user{display:flex;align-items:center;gap:12px;font-size:14px;color:var(--ink-2)}
.avatar{display:inline-flex;align-items:center;justify-content:center;width:30px;height:30px;border-radius:50%;background:var(--brand-tint);color:var(--brand-2);font-size:12px;font-weight:600}
.logout{font-size:13px}
.content{padding:24px;max-width:960px;width:100%}

/* Flash */
.flash{padding:10px 14px;border-radius:var(--radius);margin-bottom:16px;font-size:14px;border:1px solid transparent}
.flash-success{background:var(--ok-tint);color:var(--ok);border-color:#bfe3cd}
.flash-error{background:var(--danger-tint);color:var(--danger);border-color:#f3c9c4}

/* Metrics */
.metrics{display:grid;grid-template-columns:repeat(auto-fit,minmax(150px,1fr));gap:12px;margin-bottom:20px}
.metric{background:var(--surface);border:1px solid var(--line);border-radius:12px;padding:16px}
.metric-label{display:block;font-size:13px;color:var(--ink-2)}
.metric-value{display:block;font-size:26px;font-weight:600;margin-top:4px}

/* Card */
.card{background:var(--surface);border:1px solid var(--line);border-radius:12px;padding:18px 20px;margin-bottom:18px}
.card-head{display:flex;align-items:center;justify-content:space-between;margin-bottom:12px}
.section-block .card-head{border-bottom:1px solid var(--line);padding-bottom:10px}

/* Table */
.table{width:100%;border-collapse:collapse;font-size:14px}
.table th,.table td{text-align:left;padding:9px 8px;border-bottom:1px solid var(--line)}
.table th{color:var(--ink-2);font-weight:500;font-size:13px}
.table .num{text-align:right}
.table .empty,.empty{color:var(--ink-3);font-size:14px}
.empty{padding:8px 0}

/* Buttons */
.btn{display:inline-flex;align-items:center;gap:6px;padding:8px 14px;border-radius:var(--radius);border:1px solid var(--line-2);background:var(--surface);color:var(--ink);font-size:14px;font-family:inherit;cursor:pointer;line-height:1}
.btn:hover{background:var(--bg);text-decoration:none}
.btn-primary{background:var(--brand);border-color:var(--brand);color:#fff}
.btn-primary:hover{background:var(--brand-2)}
.btn-danger{background:var(--danger);border-color:var(--danger);color:#fff}
.btn-danger:hover{background:#8f1c14}
.btn-danger-ghost{color:var(--danger);border-color:transparent}
.btn-danger-ghost:hover{background:var(--danger-tint)}
.btn-sm{padding:5px 10px;font-size:13px}
.btn-block{width:100%;justify-content:center;margin-top:8px}
.icon-btn{width:28px;height:28px;padding:0;display:inline-flex;align-items:center;justify-content:center;border:1px solid var(--line-2);background:var(--surface);border-radius:6px;cursor:pointer;font-size:14px;color:var(--ink-2)}
.icon-btn:hover{background:var(--bg)}
.inline{display:inline}

/* Forms */
.form{max-width:560px}
.field{display:block;margin-bottom:16px}
.field>span{display:block;font-size:13px;color:var(--ink-2);margin-bottom:6px}
.field-narrow{max-width:220px}
input[type=text],input[type=email],input[type=password],input[type=number],select,textarea{
  width:100%;padding:9px 11px;border:1px solid var(--line-2);border-radius:var(--radius);font-size:14px;font-family:inherit;background:var(--surface);color:var(--ink)}
textarea{resize:vertical}
.hint{display:block;font-size:12px;color:var(--ink-3);margin-top:5px;font-style:normal}
.hint-inline{font-size:12px;color:var(--ink-3);font-style:normal;font-weight:400}
.err{display:block;font-size:12px;color:var(--danger);margin-top:5px;font-style:normal}
.form-actions{display:flex;gap:10px;margin-top:8px}
.breadcrumb{font-size:13px;color:var(--ink-2);margin:0 0 16px}
.lede{margin:0 0 18px;font-size:14px;max-width:70ch}
.muted{color:var(--ink-2)}

/* Topic tree */
.topics,.subtopics{list-style:none;margin:0;padding:0}
.subtopics{margin:2px 0 8px 22px;border-left:2px solid var(--line);padding-left:12px}
.topic-row{display:flex;align-items:center;gap:12px;padding:7px 4px;border-bottom:1px solid var(--line)}
.topic:last-child>.topic-row{border-bottom:0}
.topic-name{flex:1;display:flex;align-items:center;gap:8px;font-size:14px}
.topic.is-inactive .topic-name{color:var(--ink-3)}
.code{font-size:12px;color:var(--ink-2);background:var(--bg);padding:1px 7px;border-radius:5px}
.pill{font-size:11px;padding:1px 7px;border-radius:20px}
.pill-muted{background:var(--bg);color:var(--ink-3)}
.topic-meta{font-size:12px;color:var(--ink-3);white-space:nowrap}
.row-actions{display:flex;align-items:center;gap:5px;flex-wrap:wrap}

/* Auth */
.auth-body{display:flex;align-items:center;justify-content:center;min-height:100vh;padding:20px}
.auth-card{background:var(--surface);border:1px solid var(--line);border-radius:12px;padding:28px;width:100%;max-width:360px}
.auth-brand{justify-content:center;padding-bottom:20px;font-size:16px}

/* Responsive */
@media (max-width:760px){
  .app{flex-direction:column}
  .sidebar{width:100%;border-right:0;border-bottom:1px solid var(--line)}
  nav{flex-direction:row;flex-wrap:wrap}
  .nav-link{flex:0 0 auto}
  .nav-divider{display:none}
  .content{padding:16px}
}

/* ---- Badges (status / source) ---- */
.badge{display:inline-block;font-size:12px;padding:2px 9px;border-radius:20px;line-height:1.6;white-space:nowrap}
.badge-draft{background:#eef0f3;color:#5b6370}
.badge-review{background:var(--warn-tint);color:var(--warn)}
.badge-published{background:var(--ok-tint);color:var(--ok)}
.badge-archived{background:#eceef1;color:#8a909c}
.src-original{background:#eef2ff;color:#4338ca}
.src-ai{background:#fdf2d8;color:#9a6b00}
.src-licensed{background:#e9f6f4;color:#0f766e}
.diff-pill{display:inline-block;min-width:22px;text-align:center;font-size:12px;padding:1px 7px;border-radius:6px;background:var(--bg);color:var(--ink-2)}

/* ---- Editor ---- */
.form-wide{max-width:720px}
.grid-2{display:grid;grid-template-columns:1fr 1fr;gap:14px}
@media (max-width:620px){.grid-2{grid-template-columns:1fr}}
.editor-head{display:flex;align-items:center;gap:12px;margin-bottom:12px}
.subpanel{border:1px solid var(--line);border-radius:var(--radius);padding:14px 16px;margin:0 0 16px}
.subpanel legend{font-size:13px;color:var(--ink-2);padding:0 6px}
.opt-row{display:flex;align-items:center;gap:10px;margin-bottom:8px}
.opt-row input[type=text]{flex:1}
.opt-row input[type=radio]{width:18px;height:18px;flex:none}
.opt-label{width:20px;text-align:center;font-weight:600;color:var(--ink-2);flex:none}
.actions-wrap{flex-wrap:wrap}
.small{font-size:13px}
.media-grid{display:flex;flex-wrap:wrap;gap:12px;margin-bottom:14px}
.media-item{width:140px}
.media-item img{width:140px;height:100px;object-fit:cover;border:1px solid var(--line);border-radius:var(--radius);display:block;margin-bottom:6px}
.upload-form{display:flex;gap:10px;align-items:center;flex-wrap:wrap;border-top:1px solid var(--line);padding-top:14px}
.upload-form input[type=text]{width:auto;flex:1;min-width:160px}

/* ---- Bank list ---- */
.bank-top{display:flex;justify-content:space-between;align-items:flex-start;gap:12px;margin-bottom:14px;flex-wrap:wrap}
.filters{display:flex;gap:8px;flex-wrap:wrap;align-items:center}
.filters select,.filters input[type=search]{width:auto;padding:7px 10px;font-size:13px}
.bulk-bar{display:flex;align-items:center;gap:10px;margin-bottom:10px}
.bulk-bar select{width:auto;padding:7px 10px;font-size:13px}
.no-pad{padding:0;overflow:hidden}
.table-bank td,.table-bank th{padding:9px 12px}
.table-bank .chk{width:34px;text-align:center}
.table-bank tbody tr:hover{background:#fafbfc}

.pager{display:flex;align-items:center;gap:12px;justify-content:center;margin-top:16px}

/* ---- CBT preview ---- */
.cbt-frame{border:1px solid var(--line-2);border-radius:12px;overflow:hidden;background:#fff;max-width:840px}
.cbt-bar{display:flex;justify-content:space-between;align-items:center;padding:10px 16px;background:#1c2431;color:#fff;font-size:14px}
.cbt-right{display:flex;align-items:center;gap:16px}
.cbt-timer{font-variant-numeric:tabular-nums;font-weight:600}
.cbt-flag{color:#f6c453}
.cbt-body{padding:20px}
.cbt-body.has-passage{display:grid;grid-template-columns:1fr 1fr;gap:24px}
@media (max-width:680px){.cbt-body.has-passage{grid-template-columns:1fr}}
.cbt-passage{border-right:1px solid var(--line);padding-right:20px;max-height:420px;overflow:auto}
@media (max-width:680px){.cbt-passage{border-right:0;border-bottom:1px solid var(--line);padding-right:0;padding-bottom:16px}}
.cbt-passage h3{font-size:15px;margin:0 0 8px}
.passage-text{font-size:15px;line-height:1.7;color:var(--ink)}
.cbt-stem{font-size:16px;line-height:1.6;margin-bottom:16px}
.cbt-media{max-width:100%;border:1px solid var(--line);border-radius:var(--radius);margin-bottom:14px}
.cbt-options{list-style:none;margin:0;padding:0;display:flex;flex-direction:column;gap:10px}
.cbt-option{display:flex;align-items:flex-start;gap:10px;border:1px solid var(--line-2);border-radius:var(--radius);padding:12px 14px;cursor:default}
.cbt-opt-label{font-weight:600;color:var(--ink-2)}
.cbt-writing{width:100%;background:#fbfcfd}
.answer-reveal{margin-top:16px;max-width:840px}
.answer-reveal summary{cursor:pointer;font-size:14px;color:var(--brand-2);padding:8px 0}
.reveal-body{background:var(--surface);border:1px solid var(--line);border-radius:var(--radius);padding:14px 16px;font-size:14px}
.reveal-body p{margin:6px 0}

/* ---- Review queue ---- */
.nav-badge{margin-left:auto;font-style:normal;font-size:11px;font-weight:600;color:#9a6b00;background:var(--warn-tint);padding:1px 7px;border-radius:20px}
.review-meta{padding:12px 16px}
.rm-line{display:flex;align-items:center;gap:12px;flex-wrap:wrap}
.review-passage{border-left:3px solid var(--line-2);padding-left:14px;margin-bottom:16px}
.review-passage h3{font-size:15px;margin:0 0 6px}
.review-stem{font-size:16px;line-height:1.6;margin-bottom:14px}
.review-options{list-style:none;margin:0 0 14px;padding:0;display:flex;flex-direction:column;gap:8px}
.review-options li{display:flex;align-items:center;gap:10px;border:1px solid var(--line-2);border-radius:var(--radius);padding:10px 12px}
.review-options li.is-correct{border-color:#bfe3cd;background:var(--ok-tint)}
.review-options .opt-text{flex:1}
.correct-tag{font-size:11px;color:var(--ok);background:#fff;border:1px solid #bfe3cd;padding:1px 8px;border-radius:20px}
.review-explain{background:var(--bg);border-radius:var(--radius);padding:12px 14px;font-size:14px;line-height:1.6}

/* ---- Import ---- */
.bank-actions{display:flex;gap:8px}
.callout{background:var(--warn-tint);border:1px solid #f0dcaa;border-radius:var(--radius);padding:12px 14px;font-size:14px;color:#7a5600;margin:0 0 14px}
.import-preview{max-height:420px;overflow:auto;border:1px solid var(--line);border-radius:var(--radius);margin-top:12px}
.import-preview .table{margin:0}
.row-bad{background:var(--danger-tint)}
.issues{font-size:13px;color:var(--danger)}
.text-danger{color:var(--danger)}

/* ---- Student area ---- */
.check{display:block;margin:6px 0;font-size:14px}
.stu-body{background:var(--bg)}
.stu-shell{max-width:760px;margin:0 auto}
.stu-bar{display:flex;justify-content:space-between;align-items:center;padding:14px 20px;background:var(--surface);border-bottom:1px solid var(--line)}
.stu-brand{display:flex;align-items:center;gap:8px;font-weight:600}
.stu-user{font-size:14px;color:var(--ink-2)}
.stu-main{padding:24px 20px}
.stu-h1{font-size:22px;margin:0 0 18px}
.drill-form .field{max-width:none}
.drill-form .grid-2{margin-bottom:14px}

.test-topbar{position:sticky;top:0;z-index:5;display:flex;justify-content:space-between;align-items:center;background:#1c2431;color:#fff;padding:12px 18px;border-radius:10px;margin-bottom:16px}
.test-section{font-size:14px}
.test-timer{font-variant-numeric:tabular-nums;font-weight:700;font-size:18px;background:rgba(255,255,255,.12);padding:4px 12px;border-radius:8px}
.q-card{background:var(--surface);border:1px solid var(--line);border-radius:12px;padding:18px 20px;margin-bottom:14px}
.q-head{font-size:13px;color:var(--ink-3);margin-bottom:8px}
.q-passage{background:var(--bg);border-radius:var(--radius);padding:12px 14px;margin-bottom:12px;font-size:15px;line-height:1.7}
.q-stem{font-size:16px;line-height:1.6;margin-bottom:14px}
.q-options{list-style:none;margin:0;padding:0;display:flex;flex-direction:column;gap:8px}
.q-option{display:flex;align-items:flex-start;gap:10px;border:1px solid var(--line-2);border-radius:var(--radius);padding:12px 14px;cursor:pointer}
.q-option:hover{background:#fafbfc}
.q-option input{margin-top:2px}
.q-opt-label{font-weight:600;color:var(--ink-2)}
.test-actions{margin-top:18px;display:flex;gap:10px}

.result-hero{display:flex;align-items:baseline;gap:16px;background:var(--surface);border:1px solid var(--line);border-radius:12px;padding:22px 24px;margin-bottom:18px}
.result-score{font-size:40px;font-weight:700;color:var(--ink)}
.result-score span{font-size:22px;color:var(--ink-3);font-weight:500}
.result-pct{font-size:22px;color:var(--brand-2);font-weight:600}
.rev-item{border-left:3px solid var(--line-2);padding:10px 14px;margin-bottom:12px}
.rev-item.rev-ok{border-color:#7fc79f}
.rev-item.rev-no{border-color:#e59a94}
.rev-head{display:flex;justify-content:space-between;font-size:13px;color:var(--ink-3);margin-bottom:6px}
.rev-ok .rev-flag{color:var(--ok);font-weight:600}
.rev-no .rev-flag{color:var(--danger);font-weight:600}
.rev-stem{font-size:15px;margin-bottom:8px}
.rev-line{font-size:14px;margin:4px 0}
.rev-expl{color:var(--ink-2)}