:root {
  --bg: #0d1117;
  --bg-card: #161b22;
  --bg-card2: #1c2128;
  --border: #30363d;
  --border-accent: #388bfd;
  --text: #e6edf3;
  --text-muted: #7d8590;
  --text-code: #79c0ff;
  --accent: #388bfd;
  --accent-green: #3fb950;
  --accent-yellow: #d29922;
  --accent-purple: #bc8cff;
  --accent-orange: #f0883e;
  --accent-red: #f85149;
  --radius: 10px;
  --radius-sm: 6px;
  --font-mono: 'JetBrains Mono', 'Fira Code', 'Cascadia Code', monospace;
}

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

body {
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', system-ui, sans-serif;
  background: var(--bg);
  color: var(--text);
  min-height: 100vh;
  overflow-x: hidden;
}

/* ── Header ── */
header {
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 20px 32px;
  border-bottom: 1px solid var(--border);
  background: var(--bg-card);
  position: sticky;
  top: 0;
  z-index: 100;
}

header svg { flex-shrink: 0; }

.header-title {
  font-size: 16px;
  font-weight: 600;
  color: var(--text);
}

.header-sub {
  font-size: 12px;
  color: var(--text-muted);
  margin-top: 1px;
}

.progress-wrap {
  margin-left: auto;
  display: flex;
  align-items: center;
  gap: 12px;
}

.progress-track {
  width: 200px;
  height: 4px;
  background: var(--border);
  border-radius: 99px;
  overflow: hidden;
}

.progress-fill {
  height: 100%;
  background: var(--accent);
  border-radius: 99px;
  transition: width 0.4s ease;
}

.progress-label {
  font-size: 12px;
  color: var(--text-muted);
  white-space: nowrap;
}

/* ── Layout ── */
.app {
  display: grid;
  grid-template-columns: 260px 1fr;
  height: calc(100vh - 65px);
}

/* ── Sidebar ── */
.sidebar {
  border-right: 1px solid var(--border);
  overflow-y: auto;
  padding: 16px 0;
  background: var(--bg-card);
}

.sidebar-section {
  padding: 6px 16px;
  font-size: 11px;
  font-weight: 600;
  color: var(--text-muted);
  text-transform: uppercase;
  letter-spacing: 0.08em;
  margin-top: 8px;
}

.slide-nav-item {
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 8px 16px;
  cursor: pointer;
  border-radius: 0;
  transition: background 0.15s;
  border-left: 3px solid transparent;
  font-size: 13px;
  color: var(--text-muted);
}

.slide-nav-item:hover { background: var(--bg-card2); color: var(--text); }
.slide-nav-item.active { background: var(--bg-card2); border-left-color: var(--accent); color: var(--text); }
.slide-nav-item.done .nav-dot { background: var(--accent-green); }

.nav-dot {
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background: var(--border);
  flex-shrink: 0;
  transition: background 0.3s;
}

.nav-num {
  font-size: 11px;
  color: var(--text-muted);
  margin-left: auto;
  font-family: var(--font-mono);
}

/* ── Main ── */
.main {
  overflow-y: auto;
  display: flex;
  flex-direction: column;
}

.slide {
  display: none;
  flex-direction: column;
  flex: 1;
  padding: 40px 48px;
  animation: fadeIn 0.3s ease;
  max-width: 900px;
  width: 100%;
}

.slide.active { display: flex; }

@keyframes fadeIn { from { opacity: 0; transform: translateY(8px); } to { opacity: 1; transform: none; } }

/* ── Slide Parts ── */
.slide-eyebrow {
  font-size: 11px;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.1em;
  color: var(--accent);
  margin-bottom: 10px;
  display: flex;
  align-items: center;
  gap: 6px;
}

.slide-title {
  font-size: 28px;
  font-weight: 700;
  color: var(--text);
  line-height: 1.25;
  margin-bottom: 12px;
}

.slide-desc {
  font-size: 15px;
  color: var(--text-muted);
  line-height: 1.7;
  margin-bottom: 28px;
  max-width: 680px;
}

/* ── Code Block ── */
.code-block {
  background: #010409;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  overflow: hidden;
  margin: 20px 0;
  font-family: var(--font-mono);
  font-size: 13px;
  line-height: 1.7;
}

.code-header {
  display: flex;
  align-items: center;
  padding: 10px 16px;
  border-bottom: 1px solid var(--border);
  gap: 8px;
  background: #0d1117;
}

.code-lang {
  font-size: 11px;
  color: var(--text-muted);
  font-family: var(--font-mono);
}

.code-file {
  font-size: 12px;
  color: var(--text);
  font-family: var(--font-mono);
  margin-left: 4px;
}

.copy-btn {
  margin-left: auto;
  background: none;
  border: 1px solid var(--border);
  color: var(--text-muted);
  border-radius: var(--radius-sm);
  padding: 3px 10px;
  font-size: 11px;
  cursor: pointer;
  transition: all 0.15s;
}

.copy-btn:hover { border-color: var(--accent); color: var(--accent); }
.copy-btn.copied { border-color: var(--accent-green); color: var(--accent-green); }

.code-body { padding: 20px; overflow-x: auto; }

.line { display: flex; }
.ln { color: #3d4149; user-select: none; min-width: 32px; margin-right: 16px; text-align: right; font-size: 12px; }
.kw { color: #ff7b72; }
.str { color: #a5d6ff; }
.cm { color: #8b949e; font-style: italic; }
.key { color: #79c0ff; }
.val { color: #a5d6ff; }
.sym { color: #e6edf3; }
.op { color: #ff7b72; }
.nm { color: #79c0ff; }
.ev { color: #d2a8ff; }
.hl { background: rgba(56,139,253,0.08); display: flex; border-left: 2px solid var(--accent); margin-left: -20px; padding-left: 18px; margin-right: -20px; padding-right: 20px; }

/* ── Cards ── */
.cards {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(200px, 1fr));
  gap: 12px;
  margin: 20px 0;
}

.card {
  background: var(--bg-card2);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 16px;
  transition: border-color 0.2s;
}

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

.card-icon {
  font-size: 22px;
  margin-bottom: 10px;
}

.card-title {
  font-size: 13px;
  font-weight: 600;
  color: var(--text);
  margin-bottom: 4px;
}

.card-desc {
  font-size: 12px;
  color: var(--text-muted);
  line-height: 1.5;
}

/* ── Tags / Badges ── */
.badge {
  display: inline-flex;
  align-items: center;
  gap: 4px;
  padding: 2px 10px;
  border-radius: 99px;
  font-size: 11px;
  font-weight: 600;
  font-family: var(--font-mono);
}

.badge-blue { background: rgba(56,139,253,0.15); color: var(--accent); }
.badge-green { background: rgba(63,185,80,0.15); color: var(--accent-green); }
.badge-yellow { background: rgba(210,153,34,0.15); color: var(--accent-yellow); }
.badge-purple { background: rgba(188,140,255,0.15); color: var(--accent-purple); }
.badge-orange { background: rgba(240,136,62,0.15); color: var(--accent-orange); }
.badge-red { background: rgba(248,81,73,0.15); color: var(--accent-red); }

/* ── Steps ── */
.steps { display: flex; flex-direction: column; gap: 0; margin: 20px 0; }

.step {
  display: flex;
  gap: 16px;
  cursor: pointer;
}

.step-line-wrap {
  display: flex;
  flex-direction: column;
  align-items: center;
  flex-shrink: 0;
}

.step-dot {
  width: 32px;
  height: 32px;
  border-radius: 50%;
  background: var(--bg-card2);
  border: 2px solid var(--border);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 12px;
  font-weight: 600;
  color: var(--text-muted);
  transition: all 0.2s;
  flex-shrink: 0;
}

.step.active .step-dot, .step:hover .step-dot {
  border-color: var(--accent);
  color: var(--accent);
  background: rgba(56,139,253,0.1);
}

.step-connector {
  width: 2px;
  flex: 1;
  min-height: 16px;
  background: var(--border);
  margin: 4px 0;
}

.step-content { padding: 4px 0 20px; flex: 1; }

.step-label {
  font-size: 13px;
  font-weight: 600;
  color: var(--text);
  margin-bottom: 4px;
}

.step-text {
  font-size: 13px;
  color: var(--text-muted);
  line-height: 1.6;
}

/* ── Tabs ── */
.tabs {
  display: flex;
  gap: 0;
  border-bottom: 1px solid var(--border);
  margin-bottom: 0;
  overflow-x: auto;
}

.tab {
  padding: 10px 20px;
  font-size: 13px;
  cursor: pointer;
  color: var(--text-muted);
  border-bottom: 2px solid transparent;
  transition: all 0.15s;
  white-space: nowrap;
}

.tab:hover { color: var(--text); }
.tab.active { color: var(--accent); border-bottom-color: var(--accent); }

.tab-panel { display: none; }
.tab-panel.active { display: block; }

/* ── Callout ── */
.callout {
  display: flex;
  gap: 12px;
  padding: 14px 16px;
  border-radius: var(--radius);
  border: 1px solid;
  margin: 16px 0;
  font-size: 13px;
  line-height: 1.6;
}

.callout-info { background: rgba(56,139,253,0.08); border-color: rgba(56,139,253,0.3); color: var(--text); }
.callout-warn { background: rgba(210,153,34,0.08); border-color: rgba(210,153,34,0.3); color: var(--text); }
.callout-success { background: rgba(63,185,80,0.08); border-color: rgba(63,185,80,0.3); color: var(--text); }
.callout-tip { background: rgba(188,140,255,0.08); border-color: rgba(188,140,255,0.3); color: var(--text); }

.callout-icon { font-size: 16px; flex-shrink: 0; margin-top: 1px; }

/* ── Comparison Table ── */
.compare-table {
  width: 100%;
  border-collapse: collapse;
  margin: 20px 0;
  font-size: 13px;
}

.compare-table th {
  text-align: left;
  padding: 10px 14px;
  border-bottom: 1px solid var(--border);
  color: var(--text-muted);
  font-weight: 600;
  font-size: 11px;
  text-transform: uppercase;
  letter-spacing: 0.06em;
}

.compare-table td {
  padding: 10px 14px;
  border-bottom: 1px solid var(--border);
  color: var(--text);
  vertical-align: top;
}

.compare-table tr:last-child td { border-bottom: none; }
.compare-table tr:hover td { background: var(--bg-card2); }

/* ── Flow Diagram ── */
.flow {
  display: flex;
  align-items: center;
  gap: 0;
  flex-wrap: wrap;
  margin: 20px 0;
}

.flow-box {
  background: var(--bg-card2);
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  padding: 10px 16px;
  font-size: 12px;
  font-weight: 600;
  text-align: center;
  min-width: 110px;
}

.flow-arrow {
  padding: 0 8px;
  color: var(--accent);
  font-size: 18px;
}

/* ── Interactive Demo ── */
.demo-area {
  background: #010409;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 20px;
  margin: 20px 0;
}

.demo-label {
  font-size: 11px;
  color: var(--text-muted);
  text-transform: uppercase;
  letter-spacing: 0.08em;
  margin-bottom: 12px;
  font-weight: 600;
}

.trigger-btns {
  display: flex;
  gap: 8px;
  flex-wrap: wrap;
  margin-bottom: 16px;
}

.trig-btn {
  background: var(--bg-card2);
  border: 1px solid var(--border);
  color: var(--text-muted);
  border-radius: var(--radius-sm);
  padding: 6px 14px;
  font-size: 12px;
  cursor: pointer;
  transition: all 0.15s;
  font-family: var(--font-mono);
}

.trig-btn:hover, .trig-btn.selected { border-color: var(--accent); color: var(--accent); background: rgba(56,139,253,0.1); }

.yaml-preview {
  font-family: var(--font-mono);
  font-size: 12px;
  line-height: 1.7;
  color: var(--text);
  min-height: 80px;
  transition: all 0.2s;
}

/* ── Runner Selector ── */
.runner-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 12px;
  margin: 20px 0;
}

.runner-card {
  background: var(--bg-card2);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 20px;
  cursor: pointer;
  transition: all 0.2s;
  position: relative;
}

.runner-card:hover { border-color: var(--accent); }
.runner-card.selected { border-color: var(--accent); background: rgba(56,139,253,0.05); }

.runner-card .badge { margin-bottom: 10px; }
.runner-title { font-size: 14px; font-weight: 600; color: var(--text); margin-bottom: 6px; }

.runner-pros { font-size: 12px; color: var(--text-muted); line-height: 1.7; }

.runner-check {
  position: absolute;
  top: 12px;
  right: 12px;
  width: 20px;
  height: 20px;
  border-radius: 50%;
  background: var(--accent);
  display: none;
  align-items: center;
  justify-content: center;
  font-size: 10px;
}

.runner-card.selected .runner-check { display: flex; }

.runner-detail {
  display: none;
  margin-top: 16px;
  padding-top: 16px;
  border-top: 1px solid var(--border);
}

.runner-detail.show { display: block; }

/* ── Quiz ── */
.quiz-q {
  font-size: 15px;
  font-weight: 600;
  color: var(--text);
  margin-bottom: 16px;
  line-height: 1.5;
}

.quiz-options {
  display: flex;
  flex-direction: column;
  gap: 8px;
  margin-bottom: 16px;
}

.quiz-opt {
  background: var(--bg-card2);
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  padding: 12px 16px;
  cursor: pointer;
  font-size: 13px;
  color: var(--text);
  transition: all 0.15s;
  text-align: left;
}

.quiz-opt:hover { border-color: var(--accent); }
.quiz-opt.correct { border-color: var(--accent-green); background: rgba(63,185,80,0.1); color: var(--accent-green); }
.quiz-opt.wrong { border-color: var(--accent-red); background: rgba(248,81,73,0.1); color: var(--accent-red); }

.quiz-feedback {
  font-size: 13px;
  padding: 10px 14px;
  border-radius: var(--radius-sm);
  display: none;
  margin-top: 8px;
}

.quiz-feedback.show { display: block; }
.quiz-feedback.ok { background: rgba(63,185,80,0.1); color: var(--accent-green); border: 1px solid rgba(63,185,80,0.3); }
.quiz-feedback.fail { background: rgba(248,81,73,0.1); color: var(--accent-red); border: 1px solid rgba(248,81,73,0.3); }

/* ── Navigation ── */
.nav-footer {
  margin-top: auto;
  padding-top: 32px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  border-top: 1px solid var(--border);
  margin-top: 40px;
}

.btn {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 10px 20px;
  border-radius: var(--radius-sm);
  font-size: 13px;
  font-weight: 600;
  cursor: pointer;
  transition: all 0.15s;
  border: none;
  text-decoration: none;
}

.btn-primary { background: var(--accent); color: #fff; }
.btn-primary:hover { background: #58a6ff; }
.btn-ghost { background: transparent; border: 1px solid var(--border); color: var(--text-muted); }
.btn-ghost:hover { border-color: var(--accent); color: var(--accent); }
.btn:disabled { opacity: 0.35; cursor: not-allowed; }

/* ── Responsive ── */
@media (max-width: 768px) {
  .app { grid-template-columns: 1fr; height: auto; }
  .sidebar { display: none; }
  .slide { padding: 24px 20px; }
  .runner-grid { grid-template-columns: 1fr; }
  header { padding: 14px 20px; }
  .progress-wrap { display: none; }
}