:root {
  --bg: #f5f7fa;
  --surface: #ffffff;
  --surface-2: #f8fafc;
  --surface-3: #eef2f6;
  --text: #172033;
  --muted: #687386;
  --border: #e1e6ed;
  --primary: #0d6b57;
  --primary-dark: #095747;
  --primary-soft: #e8f4f0;
  --navy: #17223a;
  --navy-2: #1d2b48;
  --danger: #b42318;
  --code-bg: #111827;
  --code-text: #e5edf7;
  --shadow-sm: 0 2px 8px rgba(15, 23, 42, .05);
  --shadow: 0 18px 48px rgba(15, 23, 42, .10);
  --radius: 14px;
}

body.dark {
  --bg: #0d1420;
  --surface: #141d2b;
  --surface-2: #192435;
  --surface-3: #202d40;
  --text: #edf2f8;
  --muted: #9aa8ba;
  --border: #2a3748;
  --primary: #42ad8f;
  --primary-dark: #58b99f;
  --primary-soft: #14372e;
  --navy: #0c1320;
  --navy-2: #142035;
  --shadow-sm: 0 2px 8px rgba(0,0,0,.15);
  --shadow: 0 22px 60px rgba(0,0,0,.34);
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body { margin: 0; font-family: "Segoe UI", Inter, ui-sans-serif, system-ui, -apple-system, sans-serif; background: var(--bg); color: var(--text); }
button, input, textarea, select { font: inherit; }
button { cursor: pointer; }
.hidden { display: none !important; }
.mobile-only { display: none; }

.app-shell {
  min-height: 100vh;
  display: grid;
  grid-template-columns: 272px 1fr;
  grid-template-rows: 72px 1fr;
  grid-template-areas: "top top" "side main";
}

.topbar {
  grid-area: top;
  position: sticky;
  top: 0;
  z-index: 40;
  height: 72px;
  background: color-mix(in srgb, var(--surface) 96%, transparent);
  backdrop-filter: blur(14px);
  border-bottom: 1px solid var(--border);
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0 24px;
}
.brand { display: flex; gap: 12px; align-items: center; user-select: none; cursor: pointer; min-width: 230px; }
.brand-mark { width: 42px; height: 42px; border-radius: 11px; display: grid; place-items: center; background: var(--navy); color: #fff; font-weight: 800; font-size: 13px; letter-spacing: -.03em; box-shadow: inset 0 0 0 1px rgba(255,255,255,.08); }
.brand strong, .brand span { display: block; }
.brand strong { font-size: 15px; letter-spacing: -.01em; }
.brand span { font-size: 10px; color: var(--muted); margin-top: 3px; letter-spacing: .02em; }
.top-actions { display: flex; gap: 9px; align-items: center; }
.search-wrap { position: relative; width: min(390px, 34vw); }
.search-wrap input { width: 100%; border: 1px solid var(--border); background: var(--surface-2); color: var(--text); padding: 10px 14px 10px 36px; border-radius: 10px; outline: none; transition: .15s; }
.search-wrap input:focus { border-color: color-mix(in srgb, var(--primary) 65%, var(--border)); background: var(--surface); box-shadow: 0 0 0 3px color-mix(in srgb, var(--primary) 12%, transparent); }
.search-icon { position: absolute; left: 12px; top: 8px; color: var(--muted); font-size: 19px; }
.search-results { position: absolute; left: 0; right: 0; top: 47px; background: var(--surface); border: 1px solid var(--border); border-radius: 12px; box-shadow: var(--shadow); max-height: 360px; overflow: auto; padding: 7px; z-index: 100; }
.search-item { padding: 11px; border-radius: 8px; cursor: pointer; }
.search-item:hover { background: var(--surface-2); }
.search-item strong { display: block; font-size: 13px; }
.search-item small { color: var(--muted); }
.offline-pill { display: inline-flex; align-items: center; gap: 7px; padding: 8px 10px; border: 1px solid var(--border); border-radius: 999px; font-size: 11px; color: var(--muted); background: var(--surface); }
.offline-pill i { width: 7px; height: 7px; border-radius: 50%; background: #16a36a; box-shadow: 0 0 0 3px rgba(22,163,106,.10); }
.icon-btn { border: 1px solid var(--border); width: 40px; height: 40px; border-radius: 10px; color: var(--text); background: var(--surface); font-size: 17px; }
.btn { border: 0; border-radius: 9px; padding: 10px 14px; font-weight: 650; transition: .16s ease; }
.btn:hover { transform: translateY(-1px); }
.btn-primary { background: var(--primary); color: #fff; box-shadow: 0 5px 14px color-mix(in srgb, var(--primary) 20%, transparent); }
.btn-primary:hover { background: var(--primary-dark); }
.btn-secondary { background: var(--surface); border: 1px solid var(--border); color: var(--text); }
.btn-danger { background: #fff0ee; color: var(--danger); border: 1px solid #f6cfca; }
.lecturer-btn { white-space: nowrap; }

.sidebar { grid-area: side; background: var(--navy); color: #cfdaea; min-height: calc(100vh - 72px); display: flex; flex-direction: column; position: sticky; top: 72px; height: calc(100vh - 72px); overflow: auto; }
.sidebar-profile { margin: 18px 14px 10px; padding: 12px; border-radius: 11px; background: rgba(255,255,255,.055); border: 1px solid rgba(255,255,255,.07); display: flex; gap: 10px; align-items: center; }
.profile-avatar { width: 34px; height: 34px; display: grid; place-items: center; border-radius: 9px; background: #fff; color: #17223a; font-size: 11px; font-weight: 800; }
.sidebar-profile strong { font-size: 12px; display: block; color: #fff; }
.sidebar-profile span { display: block; font-size: 9px; color: #8898ae; margin-top: 3px; }
.sidebar-head { padding: 13px 20px 8px; font-size: 9px; letter-spacing: .16em; font-weight: 800; color: #71829a; display: flex; justify-content: space-between; align-items: center; }
#moduleNav { padding: 0 10px 18px; }
.nav-module { margin: 3px 0; }
.nav-module button { width: 100%; background: transparent; border: 0; color: #bdc9da; text-align: left; padding: 10px 11px; border-radius: 9px; display: grid; grid-template-columns: 30px minmax(0,1fr) auto; gap: 9px; align-items: center; font-size: 12px; }
.nav-module button:hover, .nav-module button.active { background: var(--navy-2); color: #fff; }
.nav-icon { width: 30px; height: 30px; border-radius: 8px; background: rgba(255,255,255,.07); display: grid; place-items: center; font-size: 10px; font-weight: 750; flex: none; }
.nav-copy { min-width: 0; }
.nav-copy strong { display: block; font-size: 11px; font-weight: 600; white-space: nowrap; overflow: hidden; text-overflow: ellipsis; }
.nav-copy small { display: block; color: #71829a; font-size: 8px; margin-top: 2px; }
.nav-progress { font-size: 9px; color: #7ed0b6; }
.sidebar-bottom { margin-top: auto; padding: 16px 18px 20px; border-top: 1px solid rgba(255,255,255,.08); }
.storage-line { display: flex; justify-content: space-between; font-size: 10px; margin-bottom: 6px; }
.storage-line span { color: #8190a6; }
.storage-line strong { color: #8fd6c1; }
.sidebar-bottom small { font-size: 9px; color: #718097; line-height: 1.5; }

.main { grid-area: main; padding: 28px 30px 44px; min-width: 0; }
.content-max { max-width: 1180px; margin: 0 auto; }

.workspace-head { display: flex; justify-content: space-between; gap: 24px; align-items: flex-start; margin: 2px 0 20px; }
.workspace-head .eyebrow { color: var(--primary); text-transform: uppercase; font-size: 10px; letter-spacing: .13em; font-weight: 800; }
.workspace-head h1 { margin: 6px 0 6px; font-size: clamp(28px, 3.6vw, 42px); letter-spacing: -.035em; line-height: 1.05; }
.workspace-head p { margin: 0; color: var(--muted); font-size: 13px; line-height: 1.6; max-width: 720px; }
.workspace-status { min-width: 210px; background: var(--surface); border: 1px solid var(--border); border-radius: 12px; padding: 13px 15px; box-shadow: var(--shadow-sm); }
.workspace-status span { color: var(--muted); font-size: 9px; text-transform: uppercase; letter-spacing: .12em; display: block; }
.workspace-status strong { font-size: 14px; display: block; margin-top: 4px; }
.workspace-status small { color: var(--muted); font-size: 9px; display: block; margin-top: 4px; }

.dashboard-top { display: grid; grid-template-columns: minmax(0,1.75fr) minmax(280px,.8fr); gap: 16px; }
.continue-card { background: linear-gradient(135deg, #17223a, #1f3451); color: #fff; border-radius: 16px; padding: 25px; min-height: 210px; position: relative; overflow: hidden; box-shadow: var(--shadow-sm); }
.continue-card::after { content:""; position:absolute; width:220px; height:220px; right:-85px; top:-65px; border-radius:50%; border:35px solid rgba(255,255,255,.045); }
.continue-label { font-size: 9px; text-transform: uppercase; letter-spacing: .14em; color: #90a1b9; font-weight: 800; }
.continue-card h2 { font-size: 24px; margin: 18px 0 7px; letter-spacing: -.02em; max-width: 620px; }
.continue-card p { color: #b9c5d6; margin: 0 0 22px; max-width: 620px; font-size: 12px; line-height: 1.65; }
.continue-meta { display: flex; gap: 16px; align-items: center; color: #91a0b5; font-size: 10px; margin-bottom: 17px; }
.continue-card .btn { background: #fff; color: #17223a; position: relative; z-index: 1; }
.overview-card { background: var(--surface); border: 1px solid var(--border); border-radius: 16px; padding: 18px; box-shadow: var(--shadow-sm); }
.overview-card h3 { margin: 0 0 15px; font-size: 13px; }
.overall-ring { width: 94px; height: 94px; margin: 5px auto 14px; border-radius: 50%; display: grid; place-items: center; background: conic-gradient(var(--primary) var(--p), var(--surface-3) 0); position: relative; }
.overall-ring::after { content:""; position:absolute; inset:8px; border-radius:50%; background:var(--surface); }
.overall-ring strong { z-index:1; font-size:20px; }
.overview-list { display: grid; gap: 8px; }
.overview-row { display: flex; justify-content: space-between; align-items: center; padding-top: 8px; border-top: 1px solid var(--border); font-size: 10px; color: var(--muted); }
.overview-row strong { color: var(--text); font-size: 11px; }

.section-head { display: flex; align-items: end; justify-content: space-between; gap: 16px; margin: 30px 0 14px; }
.section-head h2 { margin: 0; font-size: 20px; letter-spacing: -.015em; }
.section-head p { margin: 5px 0 0; color: var(--muted); font-size: 11px; }
.filter-row { display: flex; gap: 7px; flex-wrap: wrap; }
.filter-chip { border: 1px solid var(--border); background: var(--surface); color: var(--muted); border-radius: 999px; padding: 7px 10px; font-size: 10px; font-weight: 650; }
.filter-chip.active { border-color: var(--primary); color: var(--primary); background: var(--primary-soft); }
.module-grid { display: grid; grid-template-columns: repeat(3, minmax(0,1fr)); gap: 14px; }
.module-card { --accent:#0d6b57; background: var(--surface); border: 1px solid var(--border); border-radius: var(--radius); padding: 17px; box-shadow: var(--shadow-sm); transition: .18s ease; position: relative; overflow:hidden; }
.module-card::before { content:""; position:absolute; left:0; right:0; top:0; height:3px; background:var(--accent); }
.module-card:hover { transform: translateY(-3px); box-shadow: var(--shadow); border-color: color-mix(in srgb, var(--accent) 32%, var(--border)); }
.module-card-top { display: flex; align-items: center; gap: 11px; }
.module-card-icon { width: 42px; height: 42px; border-radius: 11px; display:grid; place-items:center; background: color-mix(in srgb, var(--accent) 10%, var(--surface)); color: var(--accent); border: 1px solid color-mix(in srgb, var(--accent) 18%, var(--border)); font-weight: 800; font-size: 11px; }
.module-card h3 { margin:0; font-size: 14px; letter-spacing:-.01em; }
.module-card .module-code { color: var(--muted); font-size: 9px; margin-top: 4px; }
.module-card p { color: var(--muted); font-size: 11px; line-height: 1.55; min-height: 52px; margin: 13px 0 12px; }
.module-stats { display:flex; gap:12px; color:var(--muted); font-size:9px; margin-bottom:13px; }
.progress-row { display: flex; align-items: center; gap: 10px; margin: 12px 0; }
.progress-track { flex:1; height: 6px; border-radius: 999px; background: var(--surface-3); overflow: hidden; }
.progress-fill { height: 100%; background: var(--primary); border-radius:999px; }
.progress-row span { font-size: 9px; color: var(--muted); width: 32px; text-align: right; }
.card-actions { display: flex; justify-content: space-between; align-items: center; padding-top:12px; border-top:1px solid var(--border); }
.card-actions small { color: var(--muted); font-size:9px; }
.card-link { border:0; background:transparent; color:var(--accent); padding:4px 0; font-size:10px; font-weight:750; }

.kpi-grid { display: grid; grid-template-columns: repeat(4,1fr); gap: 12px; }
.kpi { background: var(--surface); border: 1px solid var(--border); border-radius: 12px; padding: 16px; box-shadow: var(--shadow-sm); }
.kpi-label { display:flex; justify-content:space-between; align-items:center; color:var(--muted); font-size:9px; text-transform:uppercase; letter-spacing:.08em; }
.kpi strong { display: block; font-size: 23px; margin:10px 0 3px; letter-spacing:-.03em; }
.kpi span { color: var(--muted); font-size: 10px; }

.breadcrumb { color: var(--muted); font-size: 10px; margin-bottom: 14px; display:flex; align-items:center; gap:7px; }
.breadcrumb button { padding:5px 8px; font-size:10px; }
.lesson-layout { display: grid; grid-template-columns: minmax(0,1fr) 286px; gap: 18px; align-items: start; }
.lesson-paper { background: var(--surface); border: 1px solid var(--border); border-radius: var(--radius); padding: 30px; box-shadow: var(--shadow-sm); }
.lesson-kicker { display:flex; gap:8px; align-items:center; margin-bottom:9px; }
.lesson-kicker span { font-size:9px; color:var(--muted); }
.code-pill { padding:4px 7px; background:var(--primary-soft); color:var(--primary)!important; border-radius:999px; font-weight:750; }
.lesson-paper h1 { margin: 0 0 10px; font-size: 31px; letter-spacing:-.03em; }
.lesson-paper .lead { color: var(--muted); font-size: 13px; line-height: 1.7; max-width:850px; }
.lesson-content h2 { margin-top: 30px; font-size: 19px; letter-spacing:-.015em; }
.lesson-content h3 { margin-top: 22px; font-size: 15px; }
.lesson-content p, .lesson-content li { font-size: 13px; line-height: 1.78; }
.lesson-content ul { padding-left: 20px; }
.callout { border-left: 3px solid var(--primary); background: var(--primary-soft); border-radius: 0 9px 9px 0; padding: 13px 15px; margin: 19px 0; font-size: 12px; line-height:1.6; }
.code-block { background: var(--code-bg); border-radius: 11px; overflow: hidden; margin: 18px 0; border:1px solid #233048; }
.code-head { display:flex; justify-content:space-between; align-items:center; padding: 10px 13px; background: #182235; color:#8fa2bb; font-size: 9px; text-transform: uppercase; letter-spacing:.08em; }
.code-head button { border:1px solid rgba(255,255,255,.12); border-radius:7px; background:rgba(255,255,255,.04); color:#d9e4f3; padding:6px 9px; font-size:9px; }
.code-block pre { margin:0; padding: 18px; overflow:auto; color:var(--code-text); font-family: ui-monospace, SFMono-Regular, Menlo, Consolas, monospace; font-size: 12px; line-height:1.65; }
.lesson-actions { margin-top: 26px; padding-top: 20px; border-top: 1px solid var(--border); display:flex; flex-wrap:wrap; gap:8px; }
.lesson-pagination { display:flex; justify-content:space-between; gap:10px; margin-top:18px; }
.lesson-pagination .btn { font-size:10px; }
.lesson-side { position: sticky; top: 94px; display:grid; gap:12px; }
.side-card { background:var(--surface); border:1px solid var(--border); border-radius:13px; padding:15px; box-shadow:var(--shadow-sm); }
.side-card h4 { margin:0 0 11px; font-size:12px; }
.side-card-sub { color:var(--muted); font-size:9px; margin-top:-6px; margin-bottom:12px; }
.lesson-list { display:grid; gap:5px; }
.lesson-link { width:100%; border:0; background:transparent; color:var(--text); padding:8px; border-radius:8px; text-align:left; font-size:10px; display:flex; gap:8px; align-items:center; }
.lesson-link:hover, .lesson-link.active { background:var(--surface-2); }
.lesson-dot { width:18px; height:18px; border-radius:50%; display:grid; place-items:center; border:1px solid var(--border); font-size:8px; flex:none; }
.lesson-dot.done { background:var(--primary); border-color:var(--primary); color:white; }
.cert-card { background:linear-gradient(135deg,#fff8e8,#fff2cc); color:#443515; border-color:#f1dfad; }
body.dark .cert-card { background:#342c19; color:#f2dfad; border-color:#5b4b26; }

.modal { position:fixed; inset:0; background:rgba(2,8,23,.72); z-index:100; display:grid; place-items:center; padding:22px; }
.modal-card { width:min(1080px, 96vw); max-height:90vh; overflow:auto; background:var(--surface); color:var(--text); border:1px solid var(--border); border-radius:16px; box-shadow:0 30px 80px rgba(0,0,0,.35); }
.modal-head { padding:16px 18px; border-bottom:1px solid var(--border); display:flex; justify-content:space-between; align-items:center; position:sticky; top:0; background:var(--surface); z-index:2; }
.modal-head small { color:var(--primary); font-weight:800; font-size:9px; letter-spacing:.08em; }
.modal-head h3 { margin:3px 0 0; font-size:16px; }
.editor-grid { display:grid; grid-template-columns:1fr 1fr; min-height:560px; }
.editor-pane, .output-pane { min-width:0; }
.editor-pane { border-right:1px solid var(--border); }
.pane-label { background:var(--surface-2); border-bottom:1px solid var(--border); padding:9px 13px; font-size:9px; color:var(--muted); font-weight:800; letter-spacing:.08em; }
#codeEditor { width:100%; height:455px; resize:none; border:0; outline:0; padding:16px; background:#101827; color:#e6edf7; font-family:ui-monospace,SFMono-Regular,Menlo,Consolas,monospace; line-height:1.55; }
.editor-actions { padding:10px; display:flex; justify-content:flex-end; gap:8px; }
.preview-frame { width:100%; height:510px; border:0; background:white; }
.code-output { min-height:510px; margin:0; padding:18px; white-space:pre-wrap; font-family:ui-monospace,SFMono-Regular,Menlo,Consolas,monospace; color:var(--text); }
.quiz-card { width:min(680px,95vw); }
#quizBody { padding:20px; }
.quiz-question { padding:16px 0; border-bottom:1px solid var(--border); }
.quiz-question h4 { margin:0 0 12px; font-size:13px; }
.quiz-option { display:block; padding:9px 10px; border:1px solid var(--border); border-radius:8px; margin:7px 0; font-size:12px; }
.quiz-option:hover { background:var(--surface-2); }
.quiz-option input { margin-right:7px; }
.quiz-result { margin-top:16px; padding:14px; border-radius:9px; background:var(--primary-soft); font-size:12px; }

.lecturer-header { display:flex; justify-content:space-between; gap:20px; align-items:flex-start; margin-bottom:18px; }
.lecturer-header .eyebrow { color:#3f66b7; text-transform:uppercase; font-size:9px; font-weight:800; letter-spacing:.13em; }
.lecturer-header h1 { margin:6px 0 6px; font-size:32px; letter-spacing:-.03em; }
.lecturer-header p { margin:0; color:var(--muted); font-size:12px; line-height:1.6; max-width:680px; }
.admin-summary { display:grid; grid-template-columns:repeat(4,1fr); gap:10px; margin-bottom:16px; }
.admin-summary-card { background:var(--surface); border:1px solid var(--border); border-radius:12px; padding:14px; }
.admin-summary-card small { color:var(--muted); font-size:9px; text-transform:uppercase; letter-spacing:.07em; }
.admin-summary-card strong { display:block; font-size:21px; margin-top:7px; }
.admin-grid { display:grid; grid-template-columns:minmax(0,.95fr) minmax(0,1.35fr); gap:16px; align-items:start; }
.admin-stack { display:grid; gap:16px; }
.admin-card { background:var(--surface); border:1px solid var(--border); border-radius:14px; padding:18px; box-shadow:var(--shadow-sm); }
.admin-card h3 { margin:0 0 5px; font-size:14px; }
.admin-card .admin-help { margin:0 0 15px; color:var(--muted); font-size:10px; line-height:1.55; }
.form-grid { display:grid; gap:10px; }
.form-grid label { font-size:10px; color:var(--muted); font-weight:650; }
.form-grid input, .form-grid textarea, .form-grid select { width:100%; border:1px solid var(--border); border-radius:9px; background:var(--surface-2); color:var(--text); padding:10px; outline:none; margin-top:5px; }
.form-grid input:focus, .form-grid textarea:focus { border-color:var(--primary); box-shadow:0 0 0 3px color-mix(in srgb,var(--primary) 10%,transparent); }
.form-grid textarea { min-height:95px; resize:vertical; }
.admin-list { display:grid; gap:8px; max-height:540px; overflow:auto; }
.admin-item { border:1px solid var(--border); border-radius:10px; padding:12px; display:flex; justify-content:space-between; gap:10px; align-items:center; }
.admin-item strong { font-size:11px; display:block; }
.admin-item small { color:var(--muted); font-size:9px; }
.admin-item-meta { display:flex; align-items:center; gap:6px; }
.status-chip { padding:4px 7px; border-radius:999px; background:var(--surface-2); border:1px solid var(--border); font-size:8px; color:var(--muted); }
.feature-checks { display:grid; gap:9px; }
.feature-check { display:flex; align-items:flex-start; gap:9px; font-size:10px; color:var(--muted); line-height:1.5; }
.feature-check b { color:var(--text); display:block; }
.feature-check i { width:19px; height:19px; border-radius:6px; background:var(--primary-soft); color:var(--primary); display:grid; place-items:center; font-style:normal; font-size:9px; flex:none; }

.toast { position:fixed; right:22px; bottom:22px; z-index:200; background:#111827; color:white; border-radius:10px; padding:11px 14px; box-shadow:var(--shadow); font-size:11px; }

@media (max-width: 1050px) {
  .module-grid { grid-template-columns:repeat(2,1fr); }
  .dashboard-top { grid-template-columns:1fr; }
  .overview-card { display:grid; grid-template-columns:140px 1fr; gap:10px; align-items:center; }
  .overview-card h3 { grid-column:1/-1; }
  .lesson-layout { grid-template-columns:1fr; }
  .lesson-side { position:static; grid-template-columns:1fr 1fr; }
}
@media (max-width: 900px) {
  .offline-pill { display:none; }
  .admin-grid { grid-template-columns:1fr; }
  .admin-summary { grid-template-columns:repeat(2,1fr); }
}
@media (max-width: 760px) {
  .mobile-only { display:inline-flex; }
  .app-shell { display:block; }
  .topbar { padding:0 12px; height:68px; }
  .brand-copy span { display:none; }
  .search-wrap { width:42vw; }
  #lecturerToggle { display:none; }
  .sidebar { position:fixed; top:68px; left:-290px; width:272px; height:calc(100vh - 68px); z-index:90; transition:.22s; }
  .sidebar.open { left:0; }
  .main { padding:16px; }
  .mobile-menu { margin-bottom:13px; border:1px solid var(--border); background:var(--surface); color:var(--text); border-radius:9px; padding:8px 10px; }
  .workspace-head { flex-direction:column; }
  .workspace-status { width:100%; }
  .module-grid, .kpi-grid { grid-template-columns:1fr; }
  .section-head { align-items:flex-start; flex-direction:column; }
  .lesson-paper { padding:20px; }
  .lesson-side { grid-template-columns:1fr; }
  .editor-grid { grid-template-columns:1fr; }
  .editor-pane { border-right:0; border-bottom:1px solid var(--border); }
}
@media (max-width: 500px) {
  .brand strong { font-size:13px; }
  .brand { min-width:auto; }
  .search-wrap { display:none; }
  .module-grid { grid-template-columns:1fr; }
  .overview-card { display:block; }
  .admin-summary { grid-template-columns:1fr 1fr; }
}