:root {
  --bg: #0f1420;
  --bg-elev: #161d2e;
  --bg-elev-2: #1c2438;
  --border: #2a3350;
  --text: #e6ebf5;
  --text-dim: #9aa7c2;
  --accent: #4f8cff;
  --accent-2: #7c5cff;
  --green: #35d399;
  --amber: #f5b942;
  --radius: 10px;
}

* { box-sizing: border-box; }

body {
  margin: 0;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  background: var(--bg);
  color: var(--text);
  font-size: 17px;
}

.app {
  display: flex;
  flex-direction: column;
  height: 100vh;
}

.topbar {
  display: flex;
  align-items: center;
  gap: 24px;
  padding: 14px 20px;
  background: var(--bg-elev);
  border-bottom: 1px solid var(--border);
  flex-shrink: 0;
}

.brand {
  display: flex;
  align-items: center;
  gap: 10px;
  font-weight: 600;
  font-size: 20px;
  white-space: nowrap;
}
.brand-icon {
  font-size: 26px;
  color: var(--accent);
}

.overall {
  flex: 1;
  max-width: 480px;
}
.overall-label {
  font-size: 16px;
  color: var(--text-dim);
  margin-bottom: 6px;
  display: flex;
  justify-content: space-between;
}
#overall-pct {
  color: var(--text);
  font-weight: 700;
  font-size: 17px;
}
.progress-bar {
  height: 8px;
  border-radius: 999px;
  background: var(--bg-elev-2);
  overflow: hidden;
}
.progress-bar-fill {
  height: 100%;
  width: 0%;
  background: linear-gradient(90deg, var(--accent), var(--accent-2));
  transition: width 0.4s ease;
}

.reset-btn {
  background: transparent;
  border: 1px solid var(--border);
  color: var(--text-dim);
  padding: 10px 16px;
  border-radius: var(--radius);
  cursor: pointer;
  font-size: 15px;
  white-space: nowrap;
}
.reset-btn:hover {
  border-color: #e5556c;
  color: #e5556c;
}

.body {
  flex: 1;
  display: flex;
  min-height: 0;
}

.sidebar {
  width: 380px;
  flex-shrink: 0;
  overflow-y: auto;
  background: var(--bg-elev);
  border-right: 1px solid var(--border);
  padding: 10px 0 30px;
}

.phase-group {
  margin-bottom: 6px;
}
.phase-title {
  font-size: 13px;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  color: var(--text-dim);
  padding: 16px 18px 8px;
  font-weight: 700;
}

.module-item {
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 11px 18px;
  cursor: pointer;
  border-left: 3px solid transparent;
}
.module-item:hover {
  background: var(--bg-elev-2);
}
.module-item.active {
  background: var(--bg-elev-2);
  border-left-color: var(--accent);
}
.module-num {
  font-variant-numeric: tabular-nums;
  color: var(--text-dim);
  font-size: 15px;
  width: 24px;
  flex-shrink: 0;
}
.module-title {
  flex: 1;
  font-size: 16px;
  line-height: 1.35;
}
.module-badge {
  font-size: 13px;
  font-weight: 700;
  padding: 3px 9px;
  border-radius: 999px;
  background: var(--bg-elev-2);
  color: var(--text-dim);
  flex-shrink: 0;
}
.module-badge.done {
  background: rgba(53, 211, 153, 0.15);
  color: var(--green);
}
.module-badge.partial {
  background: rgba(245, 185, 66, 0.15);
  color: var(--amber);
}

.loading, .empty-state {
  padding: 40px;
  color: var(--text-dim);
  font-size: 17px;
}
.empty-state h1 {
  color: var(--text);
  font-size: 30px;
}
.empty-state p {
  max-width: 560px;
  line-height: 1.6;
  font-size: 17px;
}

.content {
  flex: 1;
  overflow-y: auto;
  padding: 36px 48px 80px;
}
.content-inner {
  max-width: 900px;
  margin: 0 auto;
}

.module-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 20px;
  margin-bottom: 8px;
}
.module-phase-tag {
  font-size: 14px;
  color: var(--accent);
  text-transform: uppercase;
  letter-spacing: 0.05em;
  font-weight: 700;
  margin-bottom: 10px;
}

/* Rendered markdown */
.markdown-body h1 {
  font-size: 32px;
  margin-top: 0;
  margin-bottom: 20px;
}
.markdown-body h2 {
  font-size: 22px;
  margin-top: 36px;
  margin-bottom: 12px;
  color: var(--accent);
  border-bottom: 1px solid var(--border);
  padding-bottom: 8px;
}
.markdown-body h3 {
  font-size: 18px;
  color: var(--text);
}
.markdown-body p, .markdown-body li {
  line-height: 1.7;
  font-size: 17px;
  color: var(--text);
}
.markdown-body ul {
  padding-left: 24px;
}
.markdown-body li {
  margin-bottom: 4px;
}
.markdown-body code {
  background: var(--bg-elev-2);
  padding: 2px 7px;
  border-radius: 4px;
  font-size: 15px;
  color: #ffd479;
}
.markdown-body pre {
  background: #0a0e18;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 18px;
  overflow-x: auto;
}
.markdown-body pre code {
  background: none;
  padding: 0;
  color: #c9d6f0;
  font-size: 15px;
  line-height: 1.6;
}
.markdown-body a {
  color: var(--accent);
}
.markdown-body strong {
  color: #fff;
}

/* Interactive checklist */
.checklist-box {
  margin-top: 32px;
  background: var(--bg-elev);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 20px 22px;
}
.checklist-box h2 {
  margin-top: 0;
  font-size: 20px;
  color: var(--text);
  display: flex;
  align-items: center;
  justify-content: space-between;
}
.checklist-progress-mini {
  font-size: 15px;
  color: var(--text-dim);
  font-weight: 500;
}
.checklist-item {
  display: flex;
  align-items: flex-start;
  gap: 12px;
  padding: 10px 0;
  border-bottom: 1px solid rgba(255,255,255,0.05);
  cursor: pointer;
}
.checklist-item:last-child {
  border-bottom: none;
}
.checklist-item input[type="checkbox"] {
  margin-top: 4px;
  width: 19px;
  height: 19px;
  accent-color: var(--green);
  cursor: pointer;
  flex-shrink: 0;
}
.checklist-item label {
  font-size: 17px;
  line-height: 1.55;
  cursor: pointer;
}
.checklist-item.checked label {
  color: var(--text-dim);
  text-decoration: line-through;
}

.nav-buttons {
  display: flex;
  justify-content: space-between;
  margin-top: 28px;
}
.nav-btn {
  background: var(--bg-elev-2);
  border: 1px solid var(--border);
  color: var(--text);
  padding: 12px 18px;
  border-radius: var(--radius);
  cursor: pointer;
  font-size: 16px;
}
.nav-btn:hover {
  border-color: var(--accent);
}
.nav-btn:disabled {
  opacity: 0.35;
  cursor: default;
}

/* Scrollbars */
::-webkit-scrollbar { width: 10px; height: 10px; }
::-webkit-scrollbar-track { background: transparent; }
::-webkit-scrollbar-thumb { background: var(--bg-elev-2); border-radius: 999px; }
::-webkit-scrollbar-thumb:hover { background: var(--border); }

.brand-home {
  margin-left: 8px;
  font-size: 12px;
  font-weight: 600;
  color: var(--text-dim);
  text-decoration: none;
  border: 1px solid var(--border);
  border-radius: 999px;
  padding: 3px 10px;
  transition: color .15s, border-color .15s;
}
.brand-home:hover {
  color: var(--accent);
  border-color: var(--accent);
}

/* Session chip */
.session-chip {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  font-size: 13px;
  color: var(--text-dim);
  background: var(--bg-elev-2);
  border: 1px solid var(--border);
  border-radius: 999px;
  padding: 6px 12px;
  max-width: 180px;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}
.session-dot {
  width: 8px; height: 8px; border-radius: 50%;
  background: #f5b942;
  flex-shrink: 0;
}
.session-chip.online .session-dot { background: var(--green); box-shadow: 0 0 8px var(--green); }

/* Modal */
.modal {
  position: fixed; inset: 0; z-index: 100;
  background: rgba(0,0,0,.65);
  display: flex; align-items: center; justify-content: center;
  padding: 1rem;
}
.modal[hidden] { display: none !important; }
.modal-card {
  position: relative;
  width: min(440px, 100%);
  background: var(--bg-elev);
  border: 1px solid var(--border);
  border-radius: 14px;
  padding: 1.5rem;
  box-shadow: 0 20px 60px rgba(0,0,0,.5);
}
.modal-close {
  position: absolute; top: 12px; right: 14px;
  background: none; border: none; color: var(--text-dim);
  font-size: 1.2rem; cursor: pointer;
}
.modal-card h2 { margin: 0 0 .4rem; font-size: 1.25rem; }
.modal-lead { color: var(--text-dim); font-size: .9rem; margin: 0 0 1rem; line-height: 1.5; }
.tabs { display: flex; gap: .5rem; margin-bottom: 1rem; }
.tab {
  flex: 1; padding: .55rem; border-radius: 8px; cursor: pointer;
  background: var(--bg-elev-2); border: 1px solid var(--border); color: var(--text-dim); font-weight: 600;
}
.tab.active { border-color: var(--accent); color: var(--text); background: rgba(79,140,255,.12); }
.tab-panel label {
  display: block; font-size: .78rem; color: var(--text-dim);
  margin: .75rem 0 .35rem; font-weight: 600;
}
.tab-panel input {
  width: 100%; padding: .65rem .8rem; border-radius: 8px;
  border: 1px solid var(--border); background: var(--bg); color: var(--text);
  font-size: .95rem; outline: none;
}
.tab-panel input:focus { border-color: var(--accent); }
.primary-btn {
  width: 100%; margin-top: 1rem; padding: .75rem;
  border: none; border-radius: 8px; cursor: pointer;
  background: var(--accent); color: #fff; font-weight: 700; font-size: .95rem;
}
.primary-btn:hover { filter: brightness(1.08); }
.hint { font-size: .78rem; color: var(--text-dim); margin-top: .85rem; line-height: 1.45; }
.hint code { color: var(--green); }
.session-result {
  margin-top: 1rem; padding: 1rem; border-radius: 8px;
  background: rgba(53,211,153,.08); border: 1px solid rgba(53,211,153,.3);
  font-size: .88rem; line-height: 1.5;
}
.session-result strong { color: var(--green); font-family: ui-monospace, monospace; }
.session-error {
  margin-top: .75rem; color: #ff7b72; font-size: .85rem;
}

/* Quiz */
.quiz-box {
  margin-top: 2rem;
  background: var(--bg-elev);
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 1.25rem 1.4rem;
}
.quiz-box h2 {
  margin: 0 0 .35rem;
  font-size: 1.2rem;
  display: flex; align-items: center; gap: .6rem; flex-wrap: wrap;
}
.quiz-lock-note {
  font-size: .85rem; color: var(--amber); margin-bottom: 1rem;
}
.quiz-pass-badge {
  font-size: .72rem; font-weight: 700; padding: .2rem .55rem;
  border-radius: 999px; background: rgba(53,211,153,.15); color: var(--green);
  border: 1px solid rgba(53,211,153,.35);
}
.quiz-q {
  margin: 1.1rem 0;
  padding-bottom: 1rem;
  border-bottom: 1px solid var(--border);
}
.quiz-q:last-of-type { border-bottom: none; }
.quiz-q-text { font-weight: 600; margin-bottom: .55rem; font-size: 1rem; }
.quiz-opts { display: flex; flex-direction: column; gap: .4rem; }
.quiz-opt {
  display: flex; gap: .55rem; align-items: flex-start;
  padding: .55rem .7rem; border-radius: 8px;
  border: 1px solid var(--border); cursor: pointer;
  background: var(--bg-elev-2); font-size: .92rem; line-height: 1.4;
}
.quiz-opt:hover { border-color: var(--accent); }
.quiz-opt.selected { border-color: var(--accent); background: rgba(79,140,255,.1); }
.quiz-opt.correct { border-color: var(--green); background: rgba(53,211,153,.1); }
.quiz-opt.wrong { border-color: #ff7b72; background: rgba(255,123,114,.08); }
.quiz-opt input { margin-top: 3px; }
.quiz-actions { display: flex; gap: .75rem; flex-wrap: wrap; align-items: center; margin-top: .5rem; }
.quiz-submit {
  background: var(--accent); color: #fff; border: none;
  padding: .65rem 1.2rem; border-radius: 8px; font-weight: 700; cursor: pointer;
}
.quiz-submit:disabled { opacity: .4; cursor: default; }
.quiz-score {
  font-size: .9rem; color: var(--text-dim);
}
.quiz-score.pass { color: var(--green); font-weight: 700; }
.quiz-score.fail { color: #ff7b72; font-weight: 700; }

.module-item.locked { opacity: .45; cursor: not-allowed; }
.module-item .lock-icon { margin-left: auto; font-size: .75rem; color: var(--amber); }
.module-badge.quiz-done { background: rgba(53,211,153,.2); color: var(--green); }

@media (max-width: 800px) {
  .session-chip { display: none; }
  .topbar { flex-wrap: wrap; }
}

.backup-row {
  display: flex;
  gap: .5rem;
  margin-top: 1rem;
  flex-wrap: wrap;
}
.backup-row .reset-btn { flex: 1; }