:root {
  font-family: Inter, ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  color: #eef2f7;
  background: #0a0d12;
  font-synthesis: none;
  text-rendering: optimizeLegibility;
  --bg: #0a0d12;
  --panel: #11161f;
  --panel-2: #171d27;
  --panel-3: #202735;
  --text: #eef2f7;
  --muted: #9aa6b6;
  --line: #2b3443;
  --accent: #7c9cff;
  --accent-2: #9bb2ff;
  --good: #46c987;
  --bad: #ff6b73;
  --warn: #f0b55b;
  --shadow: 0 18px 48px rgba(0,0,0,.28);
}

* { box-sizing: border-box; }
body { margin: 0; min-width: 320px; min-height: 100vh; background: radial-gradient(circle at top right, rgba(124,156,255,.08), transparent 34%), var(--bg); color: var(--text); }
button, input, select, textarea { font: inherit; }
button { cursor: pointer; }
button:disabled { cursor: not-allowed; opacity: .5; }

.app-shell { min-height: 100vh; display: grid; grid-template-columns: 250px minmax(0,1fr); }
.sidebar { position: sticky; top: 0; height: 100vh; padding: 22px 16px; border-right: 1px solid var(--line); background: rgba(10,13,18,.92); backdrop-filter: blur(14px); }
.brand { display:flex; align-items:center; gap:12px; padding: 4px 8px 22px; }
.brand-mark { width:38px; height:38px; border-radius:12px; display:grid; place-items:center; background: linear-gradient(135deg, var(--accent), #5b67ff); font-weight:900; box-shadow: 0 10px 24px rgba(92,108,255,.25); }
.brand h1 { font-size: 17px; margin:0; }
.brand p { margin:2px 0 0; color:var(--muted); font-size:12px; }
.nav { display:grid; gap:7px; }
.nav button { width:100%; border:0; color:var(--muted); background:transparent; text-align:left; padding:11px 12px; border-radius:10px; display:flex; align-items:center; justify-content:space-between; }
.nav button.active, .nav button:hover { color:var(--text); background:var(--panel-2); }
.sidebar-footer { position:absolute; bottom:18px; left:16px; right:16px; color:var(--muted); font-size:11px; line-height:1.5; }

.main { min-width:0; }
.topbar { min-height:68px; display:flex; justify-content:space-between; align-items:center; gap:16px; padding:14px 28px; border-bottom:1px solid var(--line); background:rgba(10,13,18,.72); backdrop-filter:blur(14px); position:sticky; top:0; z-index:5; }
.topbar h2 { margin:0; font-size:20px; }
.top-actions { display:flex; flex-wrap:wrap; gap:9px; }
.content { padding:28px; max-width:1400px; margin:0 auto; }

.btn { border:1px solid var(--line); color:var(--text); background:var(--panel-2); border-radius:10px; padding:9px 13px; font-weight:700; }
.btn:hover { background:var(--panel-3); }
.btn.primary { background:var(--accent); color:#081022; border-color:transparent; }
.btn.primary:hover { background:var(--accent-2); }
.btn.danger { color:#ffd4d7; border-color:rgba(255,107,115,.38); background:rgba(255,107,115,.08); }
.btn.ghost { background:transparent; }
.btn.small { padding:6px 9px; font-size:12px; border-radius:8px; }

.grid { display:grid; gap:16px; }
.grid.cols-4 { grid-template-columns:repeat(4,minmax(0,1fr)); }
.grid.cols-3 { grid-template-columns:repeat(3,minmax(0,1fr)); }
.grid.cols-2 { grid-template-columns:repeat(2,minmax(0,1fr)); }
.card { border:1px solid var(--line); border-radius:16px; background:linear-gradient(180deg, rgba(23,29,39,.96), rgba(16,21,29,.96)); box-shadow:var(--shadow); }
.card.pad { padding:18px; }
.stat .value { font-size:28px; font-weight:900; letter-spacing:-.02em; }
.stat .label { color:var(--muted); margin-top:5px; font-size:12px; }
.section-title { display:flex; align-items:center; justify-content:space-between; gap:12px; margin:28px 0 13px; }
.section-title h3 { margin:0; font-size:15px; }
.muted { color:var(--muted); }
.kicker { color:var(--accent-2); text-transform:uppercase; letter-spacing:.12em; font-size:11px; font-weight:900; }

.toolbar { display:flex; gap:10px; flex-wrap:wrap; align-items:center; margin-bottom:16px; }
.field, select, textarea { width:100%; border:1px solid var(--line); border-radius:10px; background:#0c1118; color:var(--text); padding:10px 11px; outline:none; }
.field:focus, select:focus, textarea:focus { border-color:var(--accent); box-shadow:0 0 0 3px rgba(124,156,255,.12); }
label { display:grid; gap:6px; color:var(--muted); font-size:12px; font-weight:700; }
.form-grid { display:grid; grid-template-columns:repeat(2,minmax(0,1fr)); gap:13px; }
.form-row { display:flex; gap:10px; align-items:end; }

.set-list, .history-list { display:grid; gap:10px; }
.set-row, .history-row { display:flex; align-items:center; justify-content:space-between; gap:14px; padding:14px 16px; border:1px solid var(--line); border-radius:13px; background:var(--panel); }
.set-row:hover { background:var(--panel-2); }
.row-main { min-width:0; }
.row-main strong { display:block; }
.row-main small { color:var(--muted); }
.row-actions { display:flex; gap:8px; flex-wrap:wrap; }

.cards-grid { display:grid; grid-template-columns:repeat(auto-fill,minmax(260px,1fr)); gap:13px; }
.study-card { padding:16px; border:1px solid var(--line); border-radius:14px; background:var(--panel); }
.study-card h4 { margin:0 0 4px; }
.study-card .meta { display:flex; gap:7px; flex-wrap:wrap; margin:10px 0 13px; }
.pill { font-size:11px; color:var(--muted); padding:5px 8px; border-radius:999px; background:var(--panel-3); border:1px solid var(--line); }
.card-fields { display:grid; gap:7px; }
.card-field-line { display:grid; grid-template-columns:minmax(90px,.45fr) 1fr; gap:9px; font-size:12px; }
.card-field-line span:first-child { color:var(--muted); }
.progress { height:7px; border-radius:999px; background:#0b1016; overflow:hidden; border:1px solid var(--line); }
.progress > i { display:block; height:100%; background:var(--accent); }

.modal-backdrop { position:fixed; inset:0; z-index:20; background:rgba(2,4,8,.75); display:grid; place-items:center; padding:20px; }
.modal { width:min(820px,100%); max-height:90vh; overflow:auto; background:#0e131b; border:1px solid var(--line); border-radius:18px; box-shadow:0 30px 90px rgba(0,0,0,.5); }
.modal-head { padding:18px 20px; border-bottom:1px solid var(--line); display:flex; justify-content:space-between; align-items:center; }
.modal-head h3 { margin:0; }
.modal-body { padding:20px; display:grid; gap:16px; }
.modal-foot { padding:14px 20px 20px; display:flex; justify-content:flex-end; gap:9px; }

.dynamic-fields { display:grid; gap:10px; }
.dynamic-row { display:grid; grid-template-columns:1fr 1.5fr auto auto; gap:8px; align-items:center; padding:10px; border:1px solid var(--line); border-radius:12px; background:var(--panel); }
.checkbox { display:flex; align-items:center; gap:7px; font-size:11px; color:var(--muted); white-space:nowrap; }
.checkbox input { width:auto; }

.quiz-setup { max-width:820px; }
.quiz-stage { max-width:980px; margin:0 auto; }
.quiz-top { display:flex; justify-content:space-between; gap:10px; align-items:center; margin-bottom:12px; }
.quiz-card { padding:24px; }
.quiz-card h2 { margin:5px 0 18px; font-size:30px; }
.quiz-detail-grid { display:grid; gap:10px; margin-bottom:20px; }
.quiz-detail { display:grid; grid-template-columns:minmax(120px,.35fr) 1fr; gap:12px; align-items:center; min-height:44px; padding:10px 12px; border-radius:10px; background:#0c1118; border:1px solid var(--line); }
.quiz-detail .label { color:var(--muted); font-size:12px; font-weight:800; }
.blank { min-height:24px; border-bottom:2px dashed #59677a; color:var(--accent-2); font-weight:800; }
.answers { display:grid; gap:16px; }
.answer-block { border-top:1px solid var(--line); padding-top:15px; }
.answer-block h4 { margin:0 0 10px; }
.choice-grid { display:grid; grid-template-columns:repeat(2,minmax(0,1fr)); gap:8px; }
.choice { text-align:left; padding:12px 13px; border:1px solid var(--line); border-radius:10px; background:var(--panel-2); color:var(--text); }
.choice:hover { border-color:#52627a; background:var(--panel-3); }
.choice.selected { border-color:var(--accent); box-shadow:0 0 0 2px rgba(124,156,255,.14); }
.choice.correct { border-color:var(--good); background:rgba(70,201,135,.09); }
.choice.wrong { border-color:var(--bad); background:rgba(255,107,115,.08); }
.feedback { padding:13px; border-radius:11px; border:1px solid var(--line); background:#0b1017; margin-top:12px; }
.feedback.good { border-color:rgba(70,201,135,.4); }
.feedback.bad { border-color:rgba(255,107,115,.4); }
.quiz-bottom { display:flex; justify-content:space-between; gap:10px; margin-top:16px; flex-wrap:wrap; }

.bar-chart { display:grid; gap:9px; }
.bar-row { display:grid; grid-template-columns:minmax(120px,.4fr) 1fr 50px; gap:10px; align-items:center; font-size:12px; }
.bar-track { height:10px; background:#0b1016; border-radius:999px; overflow:hidden; border:1px solid var(--line); }
.bar-fill { height:100%; background:var(--accent); }
.empty { padding:32px; border:1px dashed var(--line); border-radius:14px; text-align:center; color:var(--muted); }

.toast { position:fixed; right:20px; bottom:20px; z-index:50; background:#101722; border:1px solid var(--line); border-radius:12px; padding:11px 14px; box-shadow:var(--shadow); }

@media (max-width: 1000px) {
  .grid.cols-4 { grid-template-columns:repeat(2,minmax(0,1fr)); }
  .grid.cols-3 { grid-template-columns:repeat(2,minmax(0,1fr)); }
}
@media (max-width: 760px) {
  .app-shell { grid-template-columns:1fr; }
  .sidebar { height:auto; position:static; border-right:0; border-bottom:1px solid var(--line); padding:12px; }
  .brand { padding-bottom:10px; }
  .nav { grid-template-columns:repeat(4,1fr); overflow:auto; }
  .nav button { font-size:11px; padding:9px; justify-content:center; }
  .nav button span:last-child { display:none; }
  .sidebar-footer { display:none; }
  .topbar { position:static; padding:13px 16px; }
  .content { padding:16px; }
  .grid.cols-4, .grid.cols-3, .grid.cols-2, .form-grid { grid-template-columns:1fr; }
  .dynamic-row { grid-template-columns:1fr; }
  .quiz-card { padding:16px; }
  .quiz-card h2 { font-size:24px; }
  .quiz-detail { grid-template-columns:1fr; gap:5px; }
  .choice-grid { grid-template-columns:1fr; }
  .bar-row { grid-template-columns:1fr; }
}

/* Direct CSV file import */
.csv-upload{position:relative;border:1px dashed var(--line);border-radius:16px;padding:14px;display:flex;align-items:center;gap:12px;background:var(--panel);margin:4px 0 18px}.csv-upload.has-file{border-style:solid}.csv-upload input[type=file]{position:absolute;inline-size:1px;block-size:1px;opacity:0;pointer-events:none}.csv-upload-button{margin:0;display:flex;align-items:center;gap:12px;flex:1;cursor:pointer;min-width:0}.csv-upload-button>span:last-child{display:flex;flex-direction:column;min-width:0}.csv-upload-button strong{white-space:nowrap;overflow:hidden;text-overflow:ellipsis}.csv-upload-button small{font-weight:500;color:var(--muted);margin-top:3px}.csv-upload-icon{inline-size:44px;block-size:44px;border-radius:12px;display:grid;place-items:center;background:var(--soft);font-size:24px;flex:0 0 auto}.btn:disabled{opacity:.45;cursor:not-allowed;pointer-events:none}
@media(max-width:600px){.csv-upload{align-items:stretch;flex-direction:column}.csv-upload .btn{width:100%}.csv-upload-button{min-height:62px}}