:root {
  --bg: #f3f6fb; --surface: #fff; --surface2: #edf1f8; --border: #d3dbe8; --text: #0f1727; --muted: #55627b;
  --accent: #0e9f6e; --on-accent: #fff; --danger: #d93a47; --amber: #b7791f; --blue: #2f63e0;
}
@media (prefers-color-scheme: dark) {
  :root {
    --bg: #090d15; --surface: #111826; --surface2: #182134; --border: #26324b; --text: #edf2fb; --muted: #92a0ba;
    --accent: #3ddc97; --on-accent: #06130e; --danger: #f4515e; --amber: #f5b94a; --blue: #5b8cff;
  }
}
* { box-sizing: border-box; }
body { margin: 0; background: var(--bg); color: var(--text); font: 15px/1.5 -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif; }
h1, h2, h3 { margin: 0; line-height: 1.25; }
h2 { font-size: 20px; } h3 { font-size: 15px; }
.muted { color: var(--muted); } .small { font-size: 13px; }
button, input, select, textarea { font: inherit; color: inherit; }
button { cursor: pointer; border: 1px solid var(--border); background: var(--surface2); border-radius: 8px; padding: 7px 12px; }
button:hover { border-color: var(--accent); }
button.primary { background: var(--accent); color: var(--on-accent); border-color: var(--accent); font-weight: 600; }
button.danger { color: var(--danger); border-color: var(--danger); background: transparent; }
button:disabled { opacity: .5; cursor: default; }
input, select, textarea { background: var(--surface); border: 1px solid var(--border); border-radius: 8px; padding: 8px 10px; width: 100%; }
textarea { resize: vertical; min-height: 56px; }
label { display: block; font-size: 12px; color: var(--muted); margin: 8px 0 3px; }

.login { max-width: 380px; margin: 12vh auto 0; padding: 0 16px; }
.login .card { padding: 24px; }
.brand { display: flex; align-items: center; gap: 10px; font-weight: 700; font-size: 18px; }
.brand b { color: var(--accent); }
.err { color: var(--danger); margin-top: 10px; min-height: 20px; }

.shell { display: grid; grid-template-columns: 220px 1fr; min-height: 100vh; }
.side { background: var(--surface); border-right: 1px solid var(--border); padding: 18px 12px; display: flex; flex-direction: column; gap: 4px; position: sticky; top: 0; height: 100vh; }
.side .brand { padding: 0 8px 16px; }
.nav { text-align: left; border: 0; background: transparent; padding: 9px 10px; border-radius: 8px; color: var(--muted); }
.nav.on { background: var(--surface2); color: var(--text); font-weight: 600; }
.side .grow { flex: 1; }
.main { padding: 24px; max-width: 1200px; width: 100%; }
.top { display: flex; justify-content: space-between; align-items: center; gap: 12px; margin-bottom: 18px; flex-wrap: wrap; }
.card { background: var(--surface); border: 1px solid var(--border); border-radius: 12px; padding: 16px; }
.cards { display: grid; grid-template-columns: repeat(auto-fit, minmax(170px, 1fr)); gap: 12px; margin-bottom: 14px; }
.stat .n { font-size: 28px; font-weight: 700; } .stat .l { color: var(--muted); font-size: 13px; }
.charts { display: grid; grid-template-columns: repeat(auto-fit, minmax(300px, 1fr)); gap: 12px; }
.chart svg { width: 100%; height: 140px; display: block; }
.chart .total { color: var(--muted); font-size: 12px; }
.bars rect { fill: var(--accent); }
.tools { display: flex; gap: 10px; margin-bottom: 12px; align-items: center; flex-wrap: wrap; }
.tools input { max-width: 320px; }
.table-wrap { overflow-x: auto; }
table { width: 100%; border-collapse: collapse; }
th, td { text-align: left; padding: 9px 10px; border-bottom: 1px solid var(--border); white-space: nowrap; }
th { font-size: 12px; color: var(--muted); font-weight: 600; }
td.wrap { white-space: normal; }
.pill { display: inline-block; font-size: 12px; padding: 1px 8px; border-radius: 99px; background: var(--surface2); border: 1px solid var(--border); }
.pill.ok { color: var(--accent); border-color: var(--accent); } .pill.bad { color: var(--danger); border-color: var(--danger); } .pill.warn { color: var(--amber); border-color: var(--amber); }
.row-actions { display: flex; gap: 6px; }
.lessons { display: grid; gap: 10px; }
.lesson { display: grid; grid-template-columns: 1fr; gap: 6px; }
.lesson .head { display: flex; justify-content: space-between; gap: 10px; align-items: center; flex-wrap: wrap; }
.lesson .grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(220px, 1fr)); gap: 10px; }
.lesson.hidden { opacity: .75; border-style: dashed; }
.modal-bg { position: fixed; inset: 0; background: rgba(0,0,0,.5); display: grid; place-items: center; padding: 16px; z-index: 10; }
.modal { max-width: 440px; width: 100%; }
.modal .btns { display: flex; justify-content: flex-end; gap: 8px; margin-top: 14px; }
.toast { position: fixed; bottom: 18px; left: 50%; transform: translateX(-50%); background: var(--text); color: var(--bg); padding: 9px 16px; border-radius: 99px; font-size: 14px; z-index: 20; }
.soon { text-align: center; padding: 48px 16px; }

@media (max-width: 760px) {
  .shell { grid-template-columns: 1fr; }
  .side { position: static; height: auto; flex-direction: row; flex-wrap: wrap; align-items: center; padding: 10px; }
  .side .brand { padding: 0 8px 0 0; } .side .grow { display: none; }
  .main { padding: 14px; }
}