*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }

html { font-size: 16px; -webkit-font-smoothing: antialiased; }

body {
  font-family: var(--font-ui);
  background: var(--bg);
  color: var(--text);
  line-height: 1.7;
  min-height: 100vh;
}

a { color: var(--accent); text-decoration: none; }
a:hover { text-decoration: underline; }

/* ── Layout ────────────────────────────────────────────── */
.layout {
  display: flex;
  min-height: 100vh;
}

.main-content {
  flex: 1;
  margin-left: 0;
  padding: 68px 16px 56px;
  min-width: 0;
  overflow-wrap: break-word;
  word-break: break-word;
}

.content-inner {
  max-width: var(--content-max);
}

/* ── Page header ───────────────────────────────────────── */
.page-header {
  margin-bottom: 44px;
  padding-bottom: 28px;
  border-bottom: 1px solid var(--border);
}

.page-title {
  font-size: 2rem;
  font-weight: 700;
  color: var(--text);
  line-height: 1.2;
  letter-spacing: -0.025em;
  margin-bottom: 10px;
}

.page-subtitle {
  font-size: 1rem;
  color: var(--text-secondary);
  line-height: 1.65;
  max-width: 520px;
}

/* ── Topics list ───────────────────────────────────────── */
.topics-grid {
  display: flex;
  flex-direction: column;
  gap: 0;
}

/* ── Topic card ────────────────────────────────────────── */
.topic-card {
  display: flex;
  align-items: flex-start;
  gap: 18px;
  padding: 22px 0;
  border-bottom: 1px solid var(--border-light);
  text-decoration: none;
  color: inherit;
  transition: none;
}

.topic-card:first-child {
  border-top: 1px solid var(--border-light);
}

.topic-card:hover {
  text-decoration: none;
}

.topic-card:hover .topic-card__title {
  color: var(--accent);
}

.topic-card__number {
  width: 32px;
  height: 32px;
  border-radius: var(--radius-sm);
  background: var(--surface-2);
  color: var(--text-muted);
  font-size: 0.75rem;
  font-weight: 600;
  font-family: var(--font-mono);
  display: flex;
  align-items: center;
  justify-content: center;
  flex-shrink: 0;
  margin-top: 2px;
}

.topic-card__body {
  flex: 1;
  min-width: 0;
}

.topic-card__title {
  font-size: 1.05rem;
  font-weight: 600;
  color: var(--text);
  line-height: 1.35;
  margin-bottom: 5px;
  transition: color var(--transition);
}

.topic-card__desc {
  font-size: 0.9rem;
  color: var(--text-secondary);
  line-height: 1.6;
}

.topic-card__footer {
  display: flex;
  align-items: center;
  gap: 12px;
  margin-top: 10px;
}

.topic-card__tasks {
  font-size: 0.8rem;
  color: var(--text-muted);
}

.topic-card__btn {
  display: inline-flex;
  align-items: center;
  background: none;
  color: var(--accent);
  font-size: 0.82rem;
  font-weight: 500;
  text-decoration: none;
  transition: color var(--transition);
}

.topic-card__btn:hover {
  color: var(--accent-hover);
  text-decoration: underline;
}

/* ── Overall progress ──────────────────────────────────── */
.overall-progress {
  display: flex;
  align-items: center;
  gap: 14px;
  margin-bottom: 28px;
  padding: 14px 18px;
  background: var(--surface-2);
  border: 1px solid var(--border-light);
  border-radius: var(--radius-sm);
}

.overall-progress__bar {
  flex: 1;
  height: 6px;
  background: var(--surface-3);
  border-radius: 3px;
  overflow: hidden;
}

.overall-progress__fill {
  height: 100%;
  background: var(--accent);
  border-radius: 3px;
  transition: width 0.4s ease;
}

.overall-progress__label {
  font-size: 0.82rem;
  color: var(--text-secondary);
  white-space: nowrap;
}

/* ── Topic card progress ────────────────────────────────── */
.topic-card__progress {
  display: flex;
  align-items: center;
  gap: 10px;
  margin-top: 10px;
}

.topic-card__progress-bar {
  flex: 1;
  height: 4px;
  background: var(--surface-3);
  border-radius: 2px;
  overflow: hidden;
}

.topic-card__progress-fill {
  height: 100%;
  background: var(--accent);
  border-radius: 2px;
  transition: width 0.4s ease;
}

.topic-card__progress-fill--done {
  background: var(--success);
}

.topic-card__progress-text {
  font-size: 0.75rem;
  color: var(--text-muted);
  white-space: nowrap;
}

.topic-card__progress-text--done {
  color: var(--success);
  font-weight: 500;
}

.topic-card--done .topic-card__title {
  color: var(--text);
}

/* ── Loading ───────────────────────────────────────────── */
.loading {
  text-align: center;
  padding: 64px 20px;
  color: var(--text-muted);
  font-size: 0.9rem;
}

.loading-spinner {
  width: 24px;
  height: 24px;
  border: 2px solid var(--border);
  border-top-color: var(--accent);
  border-radius: 50%;
  animation: spin 0.65s linear infinite;
  margin: 0 auto 14px;
}

@keyframes spin { to { transform: rotate(360deg); } }

/* ── Desktop ──────────────────────────────────────────── */
@media (min-width: 901px) {
  .main-content {
    margin-left: var(--sidebar-width);
    padding: 52px 64px 96px;
  }

  .page-title { font-size: 2rem; }
  .page-subtitle { font-size: 1rem; }
}

/* ── Tablet ───────────────────────────────────────────── */
@media (min-width: 601px) and (max-width: 900px) {
  .main-content {
    padding: 72px 32px 64px;
  }

  .page-title { font-size: 1.7rem; }
}

/* ── Mobile ───────────────────────────────────────────── */
@media (max-width: 600px) {
  .page-title { font-size: 1.4rem; }
  .page-subtitle { font-size: 0.9rem; }

  .topic-card { gap: 12px; padding: 18px 0; }
  .topic-card__number { width: 28px; height: 28px; font-size: 0.7rem; }
  .topic-card__title { font-size: 0.95rem; }
  .topic-card__desc { font-size: 0.85rem; }

  .overall-progress { flex-direction: column; align-items: flex-start; gap: 8px; }
}

/* ── Dark mode CodeMirror ─────────────────────────────── */
[data-theme="dark"] .CodeMirror {
  background: #0d1117 !important;
  color: #e6edf3 !important;
  border-color: #30363d !important;
}

[data-theme="dark"] .CodeMirror-gutters {
  background: #161b22 !important;
  border-color: #30363d !important;
}

[data-theme="dark"] .CodeMirror-linenumber {
  color: #6e7681 !important;
}

[data-theme="dark"] .CodeMirror-cursor {
  border-left-color: #e6edf3 !important;
}

[data-theme="dark"] .CodeMirror-selected {
  background: #1f4070 !important;
}

[data-theme="dark"] .CodeMirror-line .cm-keyword   { color: #ff7b72 !important; }
[data-theme="dark"] .CodeMirror-line .cm-string    { color: #a5d6ff !important; }
[data-theme="dark"] .CodeMirror-line .cm-number    { color: #79c0ff !important; }
[data-theme="dark"] .CodeMirror-line .cm-comment   { color: #8b949e !important; font-style: italic; }
[data-theme="dark"] .CodeMirror-line .cm-def       { color: #d2a8ff !important; }
[data-theme="dark"] .CodeMirror-line .cm-builtin   { color: #ffa657 !important; }
[data-theme="dark"] .CodeMirror-line .cm-variable  { color: #e6edf3 !important; }
[data-theme="dark"] .CodeMirror-line .cm-operator  { color: #ff7b72 !important; }