/* ═══════════════════════════════════════════════════════════
   StackSimplified — DevOps Learning Portal
   Global Stylesheet
   ═══════════════════════════════════════════════════════════ */

/* ─── Design Tokens: Light Theme ─── */
:root {
  --bg: #ffffff;
  --bg-soft: #f8fafc;
  --bg-muted: #f1f5f9;
  --border: #e2e8f0;
  --border-light: #f1f5f9;
  --text: #1e293b;
  --text-dim: #475569;
  --text-muted: #94a3b8;
  --devops-primary: #FC6D26;
  --devops-primary-soft: #fff1e8;
  --devops-primary-border: #ffd3b3;
  --devops-accent: #E24329;
  --devops-accent-soft: #f0fdfa;
  --devops-accent-border: #99f6e4;
  --devops-dark: #0f172a;
  --accent: #0ea5e9;
  --accent-soft: #e0f2fe;
  --success: #10b981;
  --success-soft: #d1fae5;
  --danger: #ef4444;
  --danger-soft: #fee2e2;
  --warn: #f59e0b;
  --warn-soft: #fef3c7;
  --purple: #0d9488;
  --purple-soft: #ede9fe;
  --radius: 14px;
  --radius-sm: 8px;
  --radius-xs: 6px;
  --shadow-sm: 0 1px 3px rgba(0,0,0,0.04), 0 1px 2px rgba(0,0,0,0.03);
  --shadow-md: 0 4px 12px rgba(0,0,0,0.06);
  --shadow-lg: 0 10px 30px rgba(0,0,0,0.08);
  --transition: 0.2s ease;
}


/* ─── Design Tokens: Dark Theme ─── */
[data-theme="dark"] {
  --bg: #0f172a;
  --bg-soft: #1e293b;
  --bg-muted: #334155;
  --border: #334155;
  --border-light: #1e293b;
  --text: #f1f5f9;
  --text-dim: #cbd5e1;
  --text-muted: #64748b;
  --k8s-primary-soft: rgba(252,109,38,0.12);
  --k8s-primary-border: rgba(252,109,38,0.35);
  --k8s-accent-soft: rgba(13,148,136,0.1);
  --k8s-accent-border: rgba(13,148,136,0.3);
  --accent-soft: rgba(14,165,233,0.1);
  --purple-soft: rgba(13,148,136,0.1);
  --success-soft: rgba(252,109,38,0.1);
  --danger-soft: rgba(239,68,68,0.1);
  --warn-soft: rgba(245,158,11,0.1);
  --shadow-sm: 0 1px 3px rgba(0,0,0,0.2);
  --shadow-md: 0 4px 12px rgba(0,0,0,0.3);
  --shadow-lg: 0 10px 30px rgba(0,0,0,0.4);
}


/* ─── Base Reset & Typography ─── */
* { box-sizing: border-box; margin: 0; padding: 0; }
html { scroll-behavior: smooth; }
body {
  font-family: 'Inter', system-ui, sans-serif;
  background: var(--bg);
  color: var(--text);
  -webkit-font-smoothing: antialiased;
  min-height: 100vh;
  line-height: 1.6;
  transition: background 0.3s, color 0.3s;
}
#root { min-height: 100vh; }
code, .mono { font-family: 'JetBrains Mono', monospace; }
a { color: var(--devops-primary); text-decoration: none; }
a:hover { text-decoration: underline; }
button { cursor: pointer; font-family: inherit; }
::selection { background: rgba(252,109,38,0.15); }

::-webkit-scrollbar { width: 6px; }
::-webkit-scrollbar-track { background: var(--bg-soft); }
::-webkit-scrollbar-thumb { background: var(--border); border-radius: 4px; }


/* ─── Container ─── */
.container { max-width: 780px; margin: 0 auto; padding: 0 24px; width: 100%; }
.container-wide { max-width: 1100px; margin: 0 auto; padding: 0 24px; width: 100%; }

/* ─── Navbar ─── */
.navbar {
  position: sticky; top: 0; z-index: 100;
  height: 64px; display: flex; align-items: center; justify-content: space-between;
  padding: 0 24px; background: var(--bg); border-bottom: 1px solid var(--border);
  box-shadow: var(--shadow-sm); transition: background 0.3s;
  backdrop-filter: blur(12px);
}
.brand { display: flex; align-items: center; gap: 16px; cursor: pointer; text-decoration: none; }
.brand .logo-mark {
  width: 34px; height: 34px; border-radius: 9px;
  background: linear-gradient(135deg, var(--devops-primary), #E24329);
  display: grid; place-items: center; color: #fff; font-weight: 900; font-size: 16px;
  box-shadow: 0 4px 14px rgba(252,109,38,0.3);
}
.brand .logo-text { font-size: 16px; font-weight: 800; color: var(--text); }
.brand .logo-text span { color: var(--devops-primary); }
.nav-right { display: flex; align-items: center; gap: 8px; }
.nav-home-link {
  width: 36px; height: 36px; border-radius: 50%; border: 1px solid var(--border);
  background: var(--bg-soft); display: grid; place-items: center; font-size: 16px;
  cursor: pointer; transition: all 0.2s; text-decoration: none;
}
.nav-home-link:hover { background: var(--bg-muted); border-color: var(--devops-primary); transform: scale(1.05); text-decoration: none; }
.theme-toggle {
  width: 36px; height: 36px; border-radius: 50%; border: 1px solid var(--border);
  background: var(--bg-soft); display: grid; place-items: center; font-size: 16px;
  cursor: pointer; transition: all 0.2s;
}
.theme-toggle:hover { background: var(--bg-muted); border-color: var(--devops-primary); transform: scale(1.05); }


/* ─── Breadcrumbs ─── */
.breadcrumbs {
  display: flex; align-items: center; gap: 6px;
  font-size: 12px; color: var(--text-muted); margin-left: 16px;
  min-width: 0; overflow: hidden;
}
.breadcrumbs a { color: var(--text-muted); text-decoration: none; white-space: nowrap; }
.breadcrumbs a:hover { color: var(--devops-primary); text-decoration: none; }
.breadcrumbs .sep { opacity: 0.5; flex-shrink: 0; }
.breadcrumbs .current {
  color: var(--text-dim); font-weight: 600;
  white-space: nowrap; overflow: hidden; text-overflow: ellipsis;
}
.breadcrumbs .section-crumb {
  color: var(--text-muted); font-weight: 500; max-width: 200px;
  white-space: nowrap; overflow: hidden; text-overflow: ellipsis;
}

/* ─── Progress Bar ─── */
.reading-progress {
  position: fixed; top: 64px; left: 0; right: 0; height: 3px;
  z-index: 99; background: transparent;
}
.reading-progress-bar {
  height: 100%; background: linear-gradient(90deg, var(--devops-primary), var(--devops-accent));
  transition: width 0.1s linear; border-radius: 0 2px 2px 0;
}


/* ─── Landing Page ─── */
.chip {
  display: inline-flex; align-items: center; gap: 6px;
  padding: 6px 14px; border-radius: 999px; font-size: 12px; font-weight: 600;
  font-family: 'JetBrains Mono', monospace;
  background: var(--devops-primary-soft); border: 1px solid var(--devops-primary-border); color: var(--devops-primary);
  margin-bottom: 20px;
}
.hero-title {
  font-size: clamp(36px, 5.5vw, 64px); font-weight: 900; line-height: 1.08;
  letter-spacing: -1.5px; color: var(--text); margin-bottom: 18px;
}
.hero-title span { color: var(--devops-primary); }
.hero-sub { font-size: 18px; line-height: 1.7; color: var(--text-dim); max-width: 620px; margin: 0 auto 28px; }
.cta-btn {
  padding: 14px 28px; border-radius: 12px; border: none;
  background: linear-gradient(135deg, var(--devops-primary), #E24329); color: #fff;
  font-weight: 700; font-size: 15px; cursor: pointer;
  box-shadow: 0 6px 20px rgba(252,109,38,0.3); transition: all 0.2s;
}
.cta-btn:hover { transform: translateY(-2px); box-shadow: 0 8px 28px rgba(252,109,38,0.4); }


/* ─── Stats Bar ─── */
.stats-bar {
  display: flex; justify-content: center; gap: 32px; margin: 32px 0 48px;
  flex-wrap: wrap;
}
.stat-item { text-align: center; }
.stat-value { font-size: 24px; font-weight: 900; color: var(--devops-primary); }
.stat-label { font-size: 12px; color: var(--text-muted); font-weight: 500; margin-top: 2px; }

/* ─── Who Is This For ─── */
.who-section { margin: 48px 0; }
.section-title { font-size: 22px; font-weight: 800; color: var(--text); margin-bottom: 20px; text-align: center; }
.section-desc { font-size: 14px; color: var(--text-dim); margin-bottom: 24px; text-align: center; }
.who-grid {
  display: grid; grid-template-columns: repeat(2, 1fr); gap: 16px;
}
.who-card {
  padding: 22px; border-radius: var(--radius); border: 1px solid var(--border);
  background: var(--bg); box-shadow: var(--shadow-sm); transition: all 0.25s;
}
.who-card:hover { box-shadow: var(--shadow-md); transform: translateY(-2px); border-color: var(--devops-primary-border); }
.who-icon { font-size: 28px; display: block; margin-bottom: 10px; }
.who-card h4 { font-size: 15px; font-weight: 700; color: var(--text); margin-bottom: 6px; }
.who-card p { font-size: 13px; line-height: 1.7; color: var(--text-dim); }

/* ─── Learning Journey ─── */
.journey-section { margin: 56px 0; }
.journey-steps {
  display: flex; flex-direction: column; align-items: center; gap: 4px;
  padding: 24px; border-radius: var(--radius); border: 1px solid var(--border);
  background: var(--bg-soft);
}
.journey-step {
  display: flex; align-items: center; gap: 12px; padding: 10px 16px;
  border-radius: var(--radius-sm); width: 100%; max-width: 420px;
  transition: all 0.2s;
}
.journey-step:hover { background: var(--devops-primary-soft); }
.journey-step-num {
  width: 26px; height: 26px; border-radius: 50%; flex-shrink: 0;
  display: grid; place-items: center; font-size: 11px; font-weight: 800;
  background: var(--devops-primary); color: #fff;
}
.journey-step-icon { font-size: 18px; flex-shrink: 0; }
.journey-step-label { font-size: 14px; font-weight: 600; color: var(--text); flex: 1; }
.journey-connector { color: var(--devops-primary); font-size: 14px; opacity: 0.5; margin-left: auto; }

/* ─── Philosophy Section ─── */
.philosophy-section { margin: 56px 0; }
.philosophy-grid {
  display: grid; grid-template-columns: repeat(2, 1fr); gap: 16px;
}
.phil-card {
  padding: 22px; border-radius: var(--radius); border: 1px solid var(--border);
  background: var(--bg); box-shadow: var(--shadow-sm); transition: all 0.25s;
}
.phil-card:hover { box-shadow: var(--shadow-md); transform: translateY(-2px); border-color: var(--devops-accent-border); }
.phil-icon { font-size: 24px; margin-bottom: 10px; }
.phil-card h4 { font-size: 15px; font-weight: 700; color: var(--text); margin-bottom: 6px; }
.phil-card p { font-size: 13px; line-height: 1.7; color: var(--text-dim); }

/* ─── Roadmap ─── */
.roadmap-section { margin: 48px 0; }
.roadmap-title {
  font-size: 22px; font-weight: 800; color: var(--text); margin-bottom: 8px;
}
.roadmap-desc { font-size: 14px; color: var(--text-dim); margin-bottom: 24px; }
.roadmap-grid {
  display: grid; grid-template-columns: repeat(auto-fill, minmax(220px, 1fr));
  gap: 12px;
}
.roadmap-item {
  display: flex; align-items: center; gap: 12px;
  padding: 14px 16px; border-radius: var(--radius-sm);
  border: 1px solid var(--border); background: var(--bg);
  cursor: pointer; transition: all 0.2s; position: relative;
}
.roadmap-item:hover { border-color: var(--devops-primary-border); transform: translateY(-1px); box-shadow: var(--shadow-sm); }
.roadmap-item.active { border-color: var(--devops-primary); background: var(--devops-primary-soft); }
.roadmap-item.locked { opacity: 0.6; cursor: default; }
.roadmap-item.locked:hover { transform: none; box-shadow: none; }
.roadmap-num {
  width: 28px; height: 28px; border-radius: 50%; flex-shrink: 0;
  display: grid; place-items: center; font-size: 11px; font-weight: 800;
  background: var(--bg-muted); color: var(--text-dim); border: 1px solid var(--border);
}
.roadmap-item.active .roadmap-num { background: var(--devops-primary); color: #fff; border-color: var(--devops-primary); }
.roadmap-item-text { font-size: 13px; font-weight: 600; color: var(--text); }
.roadmap-item .lock-icon { position: absolute; top: 8px; right: 8px; font-size: 10px; opacity: 0.5; }


/* ─── Chapter Cards ─── */
.chapters-heading { font-size: 22px; font-weight: 800; color: var(--text); margin-bottom: 16px; }
.chapter-list { display: flex; flex-direction: column; gap: 16px; }
.chapter-item {
  display: flex; align-items: center; gap: 16px; padding: 20px 22px;
  border-radius: var(--radius); border: 1px solid var(--border); background: var(--bg);
  cursor: pointer; transition: all 0.25s; box-shadow: var(--shadow-sm);
}
.chapter-item:hover { border-color: var(--devops-primary-border); box-shadow: var(--shadow-md); transform: translateX(4px); }
.chapter-item-icon {
  width: 44px; height: 44px; border-radius: 12px; display: grid; place-items: center;
  font-size: 22px; background: var(--devops-primary-soft); border: 1px solid var(--devops-primary-border); flex-shrink: 0;
}
.chapter-item-body { flex: 1; }
.chapter-item-body h3 { font-size: 16px; font-weight: 700; color: var(--text); margin-bottom: 3px; }
.chapter-item-body p { font-size: 13px; color: var(--text-muted); line-height: 1.5; }
.chapter-item-meta {
  display: flex; gap: 8px; align-items: center; margin-top: 6px;
}
.chapter-item-arrow { font-size: 18px; color: var(--devops-primary); font-weight: 700; }
.footer { text-align: center; margin-top: 60px; color: var(--text-muted); font-size: 13px; }
.footer strong { color: var(--devops-primary); }


/* ─── Badges ─── */
.badge {
  display: inline-flex; align-items: center; gap: 4px;
  padding: 3px 8px; border-radius: 999px; font-size: 10px; font-weight: 700;
  font-family: 'JetBrains Mono', monospace; letter-spacing: 0.3px;
}
.badge-beginner { background: var(--success-soft); color: var(--success); border: 1px solid #a7f3d0; }
.badge-intermediate { background: var(--warn-soft); color: var(--warn); border: 1px solid #fde68a; }
.badge-advanced { background: var(--danger-soft); color: var(--danger); border: 1px solid #fecaca; }
.badge-time { background: var(--bg-muted); color: var(--text-dim); border: 1px solid var(--border); }
.badge-module { background: var(--devops-primary-soft); color: var(--devops-primary); border: 1px solid var(--devops-primary-border); }


/* ─── Chapter Layout ─── */
.layout-with-nav { display: flex; min-height: calc(100vh - 64px); }
.chapter-sidebar {
  position: sticky; top: 64px; height: calc(100vh - 64px);
  width: 280px; min-width: 280px; padding: 16px 12px; overflow-y: auto;
  border-right: 1px solid var(--border); background: var(--bg-soft); transition: background 0.3s;
  display: flex; flex-direction: column;
}

/* Sidebar: Home Button */
.sidebar-home-btn {
  display: flex; align-items: center; gap: 8px;
  padding: 10px 14px; margin-bottom: 16px; border-radius: var(--radius-sm);
  font-size: 13px; font-weight: 600; color: var(--text-dim);
  text-decoration: none; border: 1px solid var(--border); background: var(--bg);
  transition: all 0.2s;
}
.sidebar-home-btn:hover { color: var(--devops-primary); border-color: var(--devops-primary-border); background: var(--devops-primary-soft); text-decoration: none; }

/* Sidebar: Chapters list */
.sidebar-chapters { flex: 1; overflow-y: auto; }
.sidebar-chapter-group { margin-bottom: 2px; }

.sidebar-chapter-header {
  display: flex; align-items: center; gap: 8px;
  padding: 9px 12px; border-radius: var(--radius-sm);
  cursor: pointer; transition: all 0.15s; user-select: none;
}
.sidebar-chapter-header:hover { background: var(--bg-muted); }
.sidebar-chapter-header.active {
  background: var(--devops-primary-soft); color: var(--devops-primary);
}
.sidebar-chapter-num {
  width: 22px; height: 22px; border-radius: 50%; flex-shrink: 0;
  display: grid; place-items: center; font-size: 10px; font-weight: 800;
  background: var(--bg-muted); color: var(--text-muted); border: 1px solid var(--border);
}
.sidebar-chapter-header.active .sidebar-chapter-num {
  background: var(--devops-primary); color: #fff; border-color: var(--devops-primary);
}
.sidebar-chapter-title {
  font-size: 12.5px; font-weight: 600; color: var(--text-dim); flex: 1;
  line-height: 1.3; white-space: nowrap; overflow: hidden; text-overflow: ellipsis;
}
.sidebar-chapter-header.active .sidebar-chapter-title { color: var(--devops-primary); font-weight: 700; }
.sidebar-chapter-arrow {
  font-size: 9px; color: var(--text-muted); transition: transform 0.2s; flex-shrink: 0;
}
.sidebar-chapter-arrow.open { transform: rotate(90deg); }
.sidebar-chapter-header.active .sidebar-chapter-arrow { color: var(--devops-primary); }

/* Section links inside expanded chapter */
.sidebar-sections-list {
  padding: 4px 0 8px 20px; margin-left: 10px;
  border-left: 2px solid var(--border);
}
.sidebar-sec-link {
  display: block; padding: 5px 12px; margin-bottom: 1px;
  font-size: 11.5px; color: var(--text-muted); line-height: 1.4;
  text-decoration: none; border-radius: 4px; transition: all 0.15s;
  white-space: nowrap; overflow: hidden; text-overflow: ellipsis;
}
.sidebar-sec-link:hover { color: var(--text); background: var(--bg-muted); text-decoration: none; }
.sidebar-sec-link.active {
  color: var(--devops-primary); font-weight: 600; background: var(--devops-primary-soft);
}

/* Sidebar: Next chapter button */
.sidebar-next-chapter {
  margin-top: auto; padding-top: 12px; border-top: 1px solid var(--border);
}
.sidebar-next-btn {
  display: flex; flex-direction: column; gap: 2px;
  padding: 12px 14px; border-radius: var(--radius-sm);
  text-decoration: none; background: var(--bg); border: 1px solid var(--border);
  transition: all 0.2s;
}
.sidebar-next-btn:hover { border-color: var(--devops-primary-border); background: var(--devops-primary-soft); text-decoration: none; }
.sidebar-next-btn span:first-child {
  font-size: 10px; font-weight: 700; text-transform: uppercase;
  letter-spacing: 1px; color: var(--text-muted);
}
.sidebar-next-title {
  font-size: 12.5px; font-weight: 700; color: var(--devops-primary);
}


/* ─── Chapter Content ─── */
.chapter-content { flex: 1; min-width: 0; padding: 48px 56px 120px; max-width: 860px; }
.chapter-badge {
  display: inline-flex; align-items: center;
  font-family: 'JetBrains Mono', monospace; font-size: 11px; letter-spacing: 1.5px;
  color: var(--devops-primary); background: var(--devops-primary-soft); border: 1px solid var(--devops-primary-border);
  padding: 4px 12px; border-radius: 999px; margin-bottom: 12px; font-weight: 600;
}
.chapter-title { font-size: clamp(26px, 3.5vw, 36px); font-weight: 900; color: var(--text); margin-bottom: 10px; }
.chapter-overview { font-size: 16px; line-height: 1.8; color: var(--text-dim); margin-bottom: 24px; max-width: 700px; }

/* Chapter Meta Bar */
.chapter-meta {
  display: flex; align-items: center; gap: 12px; flex-wrap: wrap;
  margin-bottom: 40px; padding-bottom: 24px; border-bottom: 1px solid var(--border);
}

/* Learning Objectives */
.learning-objectives {
  padding: 24px; border-radius: var(--radius); margin-bottom: 40px;
  background: var(--devops-primary-soft); border: 1px solid var(--devops-primary-border);
}
[data-theme="dark"] .learning-objectives { border-color: rgba(252,109,38,0.3); }
.learning-objectives h3 {
  font-size: 14px; font-weight: 800; color: var(--devops-primary); margin-bottom: 12px;
  display: flex; align-items: center; gap: 8px;
}
.learning-objectives ul { list-style: none; display: flex; flex-direction: column; gap: 8px; }
.learning-objectives li {
  display: flex; align-items: flex-start; gap: 16px;
  font-size: 14px; color: var(--text-dim); line-height: 1.6;
}
.learning-objectives li::before { content: '\1F3AF'; flex-shrink: 0; }


/* ─── Sections ─── */
.section { margin-bottom: 56px; scroll-margin-top: 80px; }
.section-heading { font-size: 22px; font-weight: 800; color: var(--text); margin-bottom: 10px; }
.section-intro { font-size: 15px; line-height: 1.8; color: var(--text-dim); margin-bottom: 20px; max-width: 700px; }

/* ─── Cards ─── */
.cards { display: grid; gap: 16px; margin: 20px 0; }
.cards-2 { grid-template-columns: repeat(2, 1fr); }
.cards-3 { grid-template-columns: repeat(3, 1fr); }
.card {
  padding: 22px; border-radius: var(--radius); border: 1px solid var(--border);
  background: var(--bg); box-shadow: var(--shadow-sm); transition: all 0.25s;
}
.card:hover { box-shadow: var(--shadow-md); transform: translateY(-2px); border-color: var(--devops-primary-border); }
.card .card-icon {
  width: 42px; height: 42px; border-radius: 10px; display: grid; place-items: center;
  font-size: 20px; margin-bottom: 12px;
  background: linear-gradient(135deg, var(--devops-primary-soft), rgba(252,109,38,0.02));
  border: 1px solid var(--devops-primary-border);
}
.card h4 { font-size: 15px; font-weight: 700; color: var(--text); margin-bottom: 6px; }
.card p { font-size: 13px; line-height: 1.7; color: var(--text-dim); }


/* ─── Diagram / Flow ─── */
.diagram {
  padding: 32px; border-radius: var(--radius); border: 1px solid var(--border);
  background: var(--bg-soft); margin: 20px 0; box-shadow: var(--shadow-sm);
}
.flow { display: flex; align-items: center; justify-content: center; gap: 12px; flex-wrap: wrap; padding: 16px 0; }
.flow-node {
  padding: 16px 20px; border-radius: 12px; text-align: center; min-width: 130px;
  border: 1.5px solid var(--border); background: var(--bg); cursor: pointer;
  transition: all 0.25s; box-shadow: var(--shadow-sm);
}
.flow-node:hover { transform: scale(1.05); border-color: var(--devops-primary); box-shadow: var(--shadow-md); }
.flow-node.active { border-color: var(--devops-primary); background: var(--devops-primary-soft); box-shadow: 0 4px 16px rgba(252,109,38,0.15); }
.flow-node .fi { font-size: 24px; margin-bottom: 6px; }
.flow-node .ft { font-weight: 700; font-size: 13px; color: var(--text); }
.flow-node .fs { font-size: 11px; color: var(--text-muted); margin-top: 2px; }
.flow-arrow { color: var(--devops-primary); font-size: 20px; font-weight: 800; animation: pulse 1.8s infinite ease-in-out; }
@keyframes pulse { 0%,100%{opacity:.4;transform:translateX(0)} 50%{opacity:1;transform:translateX(4px)} }
.node-detail {
  margin-top: 16px; padding: 16px 20px; border-radius: 12px;
  background: var(--bg); border: 1px solid var(--devops-primary-border);
  font-size: 14px; line-height: 1.8; color: var(--text-dim); box-shadow: var(--shadow-sm);
}
.node-detail strong { color: var(--text); }
.diagram-hint { text-align: center; font-size: 11px; color: var(--text-muted); margin-top: 12px; font-family: 'JetBrains Mono', monospace; }


/* ─── Callout ─── */
.callout {
  display: flex; gap: 12px; align-items: flex-start;
  padding: 16px 20px; border-radius: var(--radius); margin: 18px 0;
  font-size: 14px; line-height: 1.75;
}
.callout-info { background: var(--accent-soft); border: 1px solid #bae6fd; color: #0369a1; }
.callout-success { background: var(--success-soft); border: 1px solid #a7f3d0; color: #047857; }
.callout-warn { background: var(--warn-soft); border: 1px solid #fde68a; color: #92400e; }
.callout-danger { background: var(--danger-soft); border: 1px solid #fecaca; color: #b91c1c; }
.callout-exam { background: var(--devops-primary-soft); border: 1px solid var(--devops-primary-border); color: #FC6D26; }
[data-theme="dark"] .callout-info { color: #7dd3fc; border-color: rgba(14,165,233,0.3); }
[data-theme="dark"] .callout-success { color: #6ee7b7; border-color: rgba(252,109,38,0.3); }
[data-theme="dark"] .callout-warn { color: #fcd34d; border-color: rgba(245,158,11,0.3); }
[data-theme="dark"] .callout-danger { color: #fca5a5; border-color: rgba(239,68,68,0.3); }
[data-theme="dark"] .callout-exam { color: #93c5fd; border-color: rgba(252,109,38,0.3); }


/* ─── Points List ─── */
.points { list-style: none; display: flex; flex-direction: column; gap: 16px; margin: 14px 0; }
.points li {
  display: flex; gap: 12px; align-items: flex-start; font-size: 14px; line-height: 1.75; color: var(--text-dim);
}
.points li .bullet {
  flex-shrink: 0; width: 22px; height: 22px; border-radius: 50%;
  background: var(--success-soft); border: 1px solid #a7f3d0;
  display: grid; place-items: center; font-size: 11px; color: var(--success); font-weight: 800; margin-top: 2px;
}


/* ─── Quiz ─── */
.quiz-section {
  margin: 24px 0; padding: 24px; border-radius: var(--radius);
  border: 1px solid var(--border); background: var(--bg-soft);
}
.quiz-section h3 {
  font-size: 16px; font-weight: 800; color: var(--text); margin-bottom: 16px;
  display: flex; align-items: center; gap: 8px;
}
.quiz-question { margin-bottom: 20px; }
.quiz-question p { font-size: 14px; font-weight: 600; color: var(--text); margin-bottom: 10px; }
.quiz-option {
  display: flex; align-items: center; gap: 16px;
  padding: 10px 14px; border-radius: var(--radius-sm); margin-bottom: 6px;
  border: 1px solid var(--border); background: var(--bg); cursor: pointer;
  transition: all 0.2s; font-size: 13px; color: var(--text-dim);
}
.quiz-option:hover { border-color: var(--devops-primary-border); background: var(--devops-primary-soft); }
.quiz-option.selected { border-color: var(--devops-primary); background: var(--devops-primary-soft); color: var(--text); font-weight: 600; }
.quiz-option.correct { border-color: var(--success); background: var(--success-soft); color: var(--success); }
.quiz-option.incorrect { border-color: var(--danger); background: var(--danger-soft); color: var(--danger); }
.quiz-option .option-letter {
  width: 22px; height: 22px; border-radius: 50%; flex-shrink: 0;
  display: grid; place-items: center; font-size: 11px; font-weight: 700;
  background: var(--bg-muted); border: 1px solid var(--border);
}
.quiz-explanation {
  margin-top: 8px; padding: 12px 14px; border-radius: var(--radius-sm);
  background: var(--success-soft); border: 1px solid #a7f3d0;
  font-size: 13px; color: #047857; line-height: 1.7;
}
[data-theme="dark"] .quiz-explanation { color: #6ee7b7; border-color: rgba(252,109,38,0.3); }
.quiz-check-btn {
  padding: 10px 20px; border-radius: 10px; border: none;
  background: var(--devops-primary); color: #fff; font-weight: 700;
  font-size: 13px; cursor: pointer; transition: all 0.2s; margin-top: 8px;
}
.quiz-check-btn:hover { transform: translateY(-1px); box-shadow: 0 4px 12px rgba(252,109,38,0.3); }


/* ─── Scenario Box ─── */
.scenario-box {
  margin: 24px 0; border-radius: var(--radius); overflow: hidden;
  border: 1px solid var(--border); box-shadow: var(--shadow-sm);
}
.scenario-header {
  padding: 18px 22px; background: linear-gradient(135deg, var(--devops-dark), #334155);
  color: #f1f5f9; display: flex; align-items: center; gap: 12px;
}
.scenario-header h4 { font-size: 15px; font-weight: 800; }
.scenario-header .scenario-icon { font-size: 22px; }
.scenario-body { padding: 22px; background: var(--bg); }
.scenario-body p { font-size: 14px; line-height: 1.8; color: var(--text-dim); margin-bottom: 12px; }
.scenario-requirements {
  display: grid; grid-template-columns: repeat(2, 1fr); gap: 16px; margin: 16px 0;
}
.scenario-req-item {
  padding: 12px 14px; border-radius: var(--radius-sm);
  background: var(--bg-soft); border: 1px solid var(--border);
  font-size: 13px; color: var(--text-dim); display: flex; align-items: center; gap: 8px;
}
.scenario-req-item .req-icon { font-size: 16px; }
.scenario-solution {
  margin-top: 16px; padding: 16px; border-radius: var(--radius-sm);
  background: var(--devops-primary-soft); border: 1px solid var(--devops-primary-border);
}
.scenario-solution h5 {
  font-size: 13px; font-weight: 700; color: var(--devops-primary); margin-bottom: 8px;
}
.scenario-solution p { font-size: 13px; line-height: 1.7; color: var(--text-dim); margin: 0; }


/* ─── Summary Section ─── */
.summary-section { margin: 24px 0; }
.summary-section h3 {
  font-size: 16px; font-weight: 800; color: var(--text); margin-bottom: 16px;
}
.summary-grid {
  display: grid; grid-template-columns: repeat(2, 1fr); gap: 16px;
}
.summary-item {
  display: flex; align-items: flex-start; gap: 16px; padding: 12px 14px;
  border-radius: var(--radius-sm); background: var(--bg-soft); border: 1px solid var(--border);
  font-size: 13px; line-height: 1.6; color: var(--text-dim);
}
.sum-icon { font-size: 16px; flex-shrink: 0; margin-top: 1px; }


/* ─── Chapter Nav Footer ─── */
.chapter-nav-footer {
  display: flex; justify-content: space-between; align-items: center;
  margin-top: 56px; padding-top: 24px; border-top: 1px solid var(--border);
}
.nav-prev { font-size: 14px; color: var(--text-muted); text-decoration: none; }
.nav-prev:hover { color: var(--text); text-decoration: none; }
.nav-next { font-size: 14px; font-weight: 700; color: var(--devops-primary); text-decoration: none; }
.nav-next:hover { text-decoration: underline; }
.nav-done { font-size: 14px; color: var(--success); font-weight: 600; }


/* ─── Responsive Design ─── */
@media (max-width: 900px) {
  .chapter-sidebar { display: none; }
  .chapter-content { padding: 32px 20px 80px; }
  .cards-2, .cards-3 { grid-template-columns: 1fr; }
  .summary-grid { grid-template-columns: 1fr; }
  .scenario-requirements { grid-template-columns: 1fr; }
  .who-grid { grid-template-columns: 1fr; }
  .philosophy-grid { grid-template-columns: 1fr; }
  .flow { flex-direction: column; gap: 8px; }
  .flow-arrow { transform: rotate(90deg); }
  .breadcrumbs .section-crumb { display: none; }
}

@media (max-width: 600px) {
  .navbar { padding: 0 16px; }
  .hero-title { letter-spacing: -0.5px; }
  .hero-sub { font-size: 16px; }
  .stats-bar { gap: 20px; }
  .stat-value { font-size: 20px; }
  .chapter-content { padding: 24px 16px 60px; }
  .section-heading { font-size: 18px; }
  .chapter-title { font-size: 24px; }
  .container { padding: 0 16px; }
  .roadmap-grid { grid-template-columns: 1fr; }
  .journey-step { padding: 8px 12px; }
}



/* ========== Architecture Diagram Component ========== */
  margin: 28px 0; padding: 32px; border-radius: 16px;
  background: var(--bg-soft); border: 1px solid var(--border);
  box-shadow: var(--shadow-sm);
}
  text-align: center; font-size: 20px; font-weight: 800;
  color: var(--text); margin-bottom: 4px;
}
  text-align: center; font-size: 13px; color: var(--text-muted);
  margin-bottom: 24px; font-family: 'JetBrains Mono', monospace;
}
  display: grid; grid-template-columns: 1fr 1fr; gap: 20px;
}

  border-radius: 14px; padding: 20px; border: 2px solid;
  background: var(--bg); position: relative;
}

  display: flex; align-items: center; gap: 8px;
  font-size: 15px; font-weight: 800; margin-bottom: 4px;
  padding: 8px 12px; border-radius: 8px;
}
  font-size: 12px; color: var(--text-muted); margin-bottom: 16px;
  padding-left: 12px;
}

  display: flex; flex-direction: column; gap: 8px;
}
  display: flex; align-items: center; gap: 16px;
  padding: 10px 14px; border-radius: 10px;
  border: 1.5px solid var(--border); background: var(--bg);
  cursor: pointer; transition: all 0.2s;
  box-shadow: var(--shadow-sm);
}
  border-color: var(--comp-color, var(--devops-primary));
  background: color-mix(in srgb, var(--comp-color, #FC6D26) 6%, var(--bg));
  box-shadow: 0 4px 12px color-mix(in srgb, var(--comp-color, #FC6D26) 15%, transparent);
}

/* Tooltip */
  margin-top: 20px; padding: 20px 22px; border-radius: 14px;
  background: var(--bg); border: 1px solid var(--border);
  border-left: 4px solid; box-shadow: var(--shadow-md);
}
  display: flex; align-items: center; gap: 16px; margin-bottom: 14px;
}
  display: flex; align-items: flex-start; gap: 16px;
  margin-bottom: 10px; font-size: 14px; line-height: 1.7; color: var(--text-dim);
}
  flex-shrink: 0; padding: 2px 8px; border-radius: 4px;
  font-size: 10px; font-weight: 800; letter-spacing: 0.5px;
  font-family: 'JetBrains Mono', monospace;
}



/* Architecture Diagram: Component Arrow */
  margin-left: auto; font-size: 10px; color: var(--text-muted);
  transition: color 0.2s;
}

/* Architecture Diagram: Popup Overlay */
  position: fixed; top: 0; left: 0; width: 100vw; height: 100vh; z-index: 99999;
  background: rgba(0,0,0,0.6); opacity: 0; transition: opacity 0.2s;
  display: flex; align-items: center; justify-content: center;
  padding: 24px;
}
  background: var(--bg); border-radius: 18px;
  border: 1px solid var(--border); border-top: 4px solid;
  box-shadow: 0 20px 60px rgba(0,0,0,0.3);
  max-width: 520px; width: 100%; max-height: 80vh; overflow-y: auto;
}
  display: flex; align-items: center; justify-content: space-between;
  padding: 20px 24px 0;
}
  display: flex; align-items: center; gap: 12px;
}
  width: 32px; height: 32px; border-radius: 50%;
  border: 1px solid var(--border); background: var(--bg-soft);
  display: grid; place-items: center; font-size: 14px;
  color: var(--text-muted); cursor: pointer; transition: all 0.2s;
}

  font-size: 15px; line-height: 1.75; color: var(--text-dim); margin-top: 6px;
}
  display: inline-block; padding: 3px 10px; border-radius: 5px;
  font-size: 11px; font-weight: 800; letter-spacing: 0.5px;
  font-family: 'JetBrains Mono', monospace;
}

/* ─── Diagram Popup (click-to-open) ─── */
.diagram-overlay {
  position: fixed; top: 0; left: 0; width: 100vw; height: 100vh; z-index: 99999;
  background: rgba(0,0,0,0.6); opacity: 0; transition: opacity 0.2s;
  display: flex; align-items: center; justify-content: center;
  padding: 24px;
}
.diagram-popup {
  background: var(--bg); border-radius: 18px;
  border: 1px solid var(--border);
  box-shadow: 0 20px 60px rgba(0,0,0,0.3);
  max-width: 500px; width: 100%; padding: 24px 28px; transform: scale(0.95); transition: transform 0.2s;
}
.diagram-popup-header {
  display: flex; align-items: center; justify-content: space-between;
  margin-bottom: 12px;
}
.diagram-popup-title {
  display: flex; align-items: center; gap: 16px;
  font-size: 20px; font-weight: 800; color: var(--text);
}
.diagram-popup-close {
  width: 32px; height: 32px; border-radius: 50%;
  border: 1px solid var(--border); background: var(--bg-soft);
  display: grid; place-items: center; font-size: 14px;
  color: var(--text-muted); cursor: pointer; transition: all 0.2s;
}
.diagram-popup-close:hover { background: var(--bg-muted); color: var(--text); }
.diagram-popup-sub {
  font-size: 13px; color: var(--text-muted); margin-bottom: 14px;
  font-weight: 600; font-family: monospace;
}
.diagram-popup-detail {
  font-size: 15px; line-height: 1.8; color: var(--text-dim);
}


@keyframes fadeIn { from { opacity: 0; } to { opacity: 1; } }
@keyframes scaleIn { from { opacity: 0; transform: scale(0.92) translateY(10px); } to { opacity: 1; transform: scale(1) translateY(0); } }




/* ─── Infinity Loop Component ─── */
.infinity-container { max-width: 100%;
  margin: 24px 0; padding: 32px 24px; border-radius: 16px;
  background: var(--bg-soft); border: 1px solid var(--border);
}
.infinity-labels {
  display: flex; justify-content: space-around; margin-bottom: 12px;
}
.infinity-label {
  font-size: 12px; font-weight: 800; letter-spacing: 2px;
  font-family: 'JetBrains Mono', monospace; padding: 4px 14px;
  border-radius: 999px;
}
.dev-label { color: #6366f1; background: rgba(99,102,241,0.1); border: 1px solid rgba(99,102,241,0.3); }
.ops-label { color: #ef4444; background: rgba(239,68,68,0.1); border: 1px solid rgba(239,68,68,0.3); }

.infinity-shape {
  display: flex; align-items: center; justify-content: center; gap: 0;
}
.infinity-loop {
  min-height: 220px;
  display: grid; grid-template-columns: 1fr 1fr; gap: 16px;
  padding: 28px 32px; border-radius: 50px;
  border: 2px solid var(--border); position: relative;
}
.infinity-left { border-color: rgba(99,102,241,0.3); background: rgba(99,102,241,0.03); }
.infinity-right { border-color: rgba(239,68,68,0.3); background: rgba(239,68,68,0.03); }

.infinity-center {
  font-size: 36px; font-weight: 900; color: var(--text-muted);
  margin: 0 -8px; z-index: 2; background: var(--bg-soft);
  width: 44px; height: 44px; display: grid; place-items: center;
  border-radius: 50%; border: 2px solid var(--border);
}

.infinity-node {
  display: flex; flex-direction: column; align-items: center; gap: 4px;
  padding: 16px 12px; border-radius: 14px; cursor: pointer;
  border: 1.5px solid var(--border); background: var(--bg);
  transition: all 0.2s; min-width: 110px;
}
.infinity-node:hover { border-color: var(--node-color); transform: scale(1.05);
  box-shadow: 0 4px 12px color-mix(in srgb, var(--node-color) 20%, transparent); }
.infinity-node.active { border-color: var(--node-color); background: color-mix(in srgb, var(--node-color) 8%, var(--bg)); }
.infinity-node-icon { font-size: 26px; }
.infinity-node-label { font-size: 12px; font-weight: 700; color: var(--text); }

.infinity-hint {
  text-align: center; margin-top: 14px; font-size: 12px;
  color: var(--text-muted); font-family: 'JetBrains Mono', monospace;
}

@media(max-width:600px) {
  .infinity-shape { flex-direction: column; gap: 8px; }
  .infinity-center { margin: -8px 0; }
  .infinity-loop {
  min-height: 220px; grid-template-columns: 1fr 1fr; padding: 12px; border-radius: 30px; }
  .infinity-node { padding: 8px 4px; min-width: 60px; }
  .infinity-node-icon { font-size: 18px; }
  .infinity-node-label { font-size: 10px; }
}