:root {
  --primary: #04AA6D;
  --primary-dark: #059862;
  --primary-light: #E7F6F2;
  --dark: #282A35;
  --dark-bg: #1E1E1E;
  --text: #333;
  --text-light: #666;
  --border: #E0E0E0;
  --bg: #fff;
  --bg-alt: #F9F9F9;
  --yellow: #FFC107;
  --orange: #FF9800;
  --red: #F44336;
  --blue: #2196F3;
  --purple: #9C27B0;
}
* { box-sizing: border-box; margin: 0; padding: 0; }
body { font-family: 'Inter', -apple-system, BlinkMacSystemFont, sans-serif; color: var(--text); line-height: 1.7; background: var(--bg); }
code, pre, .code { font-family: 'Source Code Pro', 'Courier New', monospace; }

/* HEADER */
header { background: var(--dark); color: white; position: sticky; top: 0; z-index: 1000; box-shadow: 0 2px 4px rgba(0,0,0,0.1); }
.header-content { max-width: 1400px; margin: 0 auto; padding: 0 24px; display: flex; align-items: center; justify-content: space-between; height: 60px; }
.logo { font-size: 18px; font-weight: 700; display: flex; align-items: center; gap: 10px; cursor: pointer; color: white; text-decoration: none; }
.logo-icon { background: var(--primary); width: 32px; height: 32px; display: grid; place-items: center; border-radius: 4px; font-size: 18px; flex-shrink: 0; }
.header-right { display: flex; align-items: center; gap: 16px; font-size: 14px; }
.header-progress { display: flex; align-items: center; gap: 12px; font-size: 14px; color: white; }
.progress-bar-container { width: 160px; height: 8px; background: rgba(255,255,255,0.2); border-radius: 4px; overflow: hidden; }
.progress-bar-fill { height: 100%; background: var(--primary); width: 0%; transition: width 0.3s ease; }
.header-btn { color: #fff; text-decoration: none; opacity: 0.85; font-size: 13px; padding: 5px 10px; border: 1px solid rgba(255,255,255,0.3); border-radius: 4px; transition: all 0.2s; cursor: pointer; background: none; display: flex; align-items: center; gap: 6px; }
.header-btn:hover { opacity: 1; background: rgba(255,255,255,0.1); }
.header-link { color: #fff; text-decoration: none; opacity: 0.85; font-size: 13px; padding: 5px 10px; border: 1px solid rgba(255,255,255,0.3); border-radius: 4px; transition: all 0.2s; }
.header-link:hover { opacity: 1; background: rgba(255,255,255,0.1); }

/* HERO */
.hero { background: linear-gradient(135deg, var(--dark) 0%, #1a4d3f 100%); color: white; padding: 60px 24px; text-align: center; }
.hero-content { max-width: 900px; margin: 0 auto; }
.hero h1 { font-size: 48px; font-weight: 700; margin-bottom: 16px; line-height: 1.2; }
.hero h1 .highlight { color: var(--primary); background: rgba(4,170,109,0.15); padding: 0 8px; border-radius: 4px; }
.hero p { font-size: 20px; opacity: 0.9; margin-bottom: 32px; }
.hero-stats { display: flex; justify-content: center; gap: 48px; flex-wrap: wrap; margin-top: 40px; }
.stat { text-align: center; }
.stat-value { font-size: 32px; font-weight: 700; color: var(--primary); display: block; }
.stat-label { font-size: 14px; opacity: 0.8; margin-top: 4px; }

/* HOME VIEW */
.home-chapters { max-width: 1200px; margin: 0 auto; padding: 48px 24px; }
.home-intro { background: var(--primary-light); border-left: 4px solid var(--primary); padding: 20px 24px; border-radius: 4px; margin-bottom: 40px; }
.home-intro h3 { color: var(--primary-dark); font-size: 17px; margin-bottom: 8px; }
.home-intro p { color: var(--text); }
.section-title { font-size: 24px; font-weight: 700; color: var(--dark); margin-bottom: 24px; display: flex; align-items: center; gap: 10px; }

/* CHAPTER GRID */
.chapter-grid { display: grid; grid-template-columns: repeat(2, 1fr); gap: 20px; }
.chapter-card { border: 1px solid var(--border); border-radius: 8px; padding: 24px; background: var(--bg); transition: all 0.2s; cursor: pointer; display: flex; flex-direction: column; gap: 14px; text-decoration: none; color: var(--text); }
.chapter-card:hover { border-color: var(--primary); box-shadow: 0 4px 16px rgba(4,170,109,0.12); transform: translateY(-2px); }
.chapter-card.case-studies-card { background: var(--dark); color: white; border-color: var(--dark); }
.chapter-card.case-studies-card:hover { border-color: var(--primary); box-shadow: 0 4px 20px rgba(4,170,109,0.25); }
.chapter-card-top { display: flex; align-items: flex-start; justify-content: space-between; gap: 12px; }
.chapter-num { font-size: 12px; font-weight: 600; text-transform: uppercase; letter-spacing: 0.5px; color: var(--primary); }
.case-studies-card .chapter-num { color: var(--primary); }
.level-badge { font-size: 11px; padding: 3px 10px; border-radius: 20px; font-weight: 600; }
.level-badge.beginner { background: #E8F5E9; color: #2E7D32; }
.level-badge.intermediate { background: #FFF3E0; color: #E65100; }
.level-badge.advanced { background: #FCE4EC; color: #C2185B; }
.level-badge.practice { background: #E3F2FD; color: #1565C0; }
.level-badge.special { background: rgba(4,170,109,0.2); color: var(--primary); }
.chapter-card h3 { font-size: 19px; font-weight: 700; color: var(--dark); line-height: 1.3; margin: 0; }
.case-studies-card h3 { color: white; font-size: 20px; }
.chapter-card-meta { display: flex; gap: 16px; font-size: 13px; color: var(--text-light); }
.case-studies-card .chapter-card-meta { color: rgba(255,255,255,0.6); }
.chapter-progress-wrap { display: flex; flex-direction: column; gap: 6px; }
.chapter-progress-label { display: flex; justify-content: space-between; font-size: 12px; color: var(--text-light); }
.chapter-progress-bar { height: 6px; background: var(--border); border-radius: 3px; overflow: hidden; }
.chapter-progress-fill { height: 100%; background: var(--primary); border-radius: 3px; transition: width 0.3s; }
.chapter-cta { display: inline-flex; align-items: center; justify-content: center; gap: 8px; padding: 10px 20px; border-radius: 4px; font-weight: 600; font-size: 14px; border: none; cursor: pointer; transition: all 0.2s; background: var(--primary); color: white; width: 100%; text-decoration: none; }
.chapter-cta:hover { background: var(--primary-dark); }
.chapter-cta.completed { background: #E8F5E9; color: #2E7D32; }
.case-studies-card .chapter-cta { background: var(--primary); color: white; }

/* LESSON VIEW */
.lesson-layout, .page-with-sidebar { max-width: 1400px; margin: 0 auto; display: grid; grid-template-columns: 280px 1fr; min-height: calc(100vh - 60px); }
.sidebar { background: var(--bg-alt); border-right: 1px solid var(--border); position: sticky; top: 60px; height: calc(100vh - 60px); overflow-y: auto; display: flex; flex-direction: column; }
.sidebar-inner { padding: 20px 0; display: flex; flex-direction: column; height: 100%; }
.sidebar-back { display: block; padding: 10px 20px; color: var(--primary); text-decoration: none; font-size: 13px; font-weight: 600; border-bottom: 1px solid var(--border); margin-bottom: 12px; }
.sidebar-back:hover { text-decoration: underline; }
.sidebar-chapter-title { padding: 8px 20px 12px; font-size: 11px; text-transform: uppercase; letter-spacing: 0.5px; color: var(--text-light); font-weight: 600; }
.sidebar-lessons { flex: 1; padding: 8px 0; overflow-y: auto; }
.sidebar-lesson-item { display: flex; align-items: center; gap: 10px; padding: 10px 20px; color: var(--text); text-decoration: none; font-size: 13px; border-left: 3px solid transparent; transition: all 0.15s; }
.sidebar-lesson-item:hover { background: rgba(4,170,109,0.05); border-left-color: var(--primary); }
.sidebar-lesson-item.active { background: var(--primary-light); border-left-color: var(--primary); color: var(--primary-dark); font-weight: 600; }
.sidebar-lesson-item.completed .lesson-check { background: var(--primary); border-color: var(--primary); }
.sidebar-lesson-item.completed .lesson-check svg { opacity: 1; }
.lesson-check { width: 18px; height: 18px; border: 2px solid var(--border); border-radius: 3px; display: grid; place-items: center; flex-shrink: 0; }
.lesson-check svg { opacity: 0; }
.sidebar-quiz-btn { display: block; margin: 12px 16px; padding: 10px 16px; background: var(--primary-light); color: var(--primary-dark); border-radius: 6px; text-decoration: none; font-size: 13px; font-weight: 600; text-align: center; border: 1px solid rgba(4,170,109,0.3); }
.sidebar-quiz-btn:hover { background: var(--primary); color: white; }
.badge { font-size: 10px; padding: 2px 6px; border-radius: 3px; font-weight: 600; margin-left: auto; }
.badge.beginner { background: #E8F5E9; color: #2E7D32; }
.badge.intermediate { background: #FFF3E0; color: #E65100; }
.badge.advanced { background: #FCE4EC; color: #C2185B; }
.badge.practice { background: #E3F2FD; color: #1565C0; }

/* MAIN CONTENT */
.main-content { padding: 48px; max-width: 900px; }
.breadcrumb { font-size: 13px; color: var(--text-light); margin-bottom: 24px; }
.breadcrumb a { color: var(--primary); text-decoration: none; }
.breadcrumb a:hover { text-decoration: underline; }
.lesson-header { margin-bottom: 32px; }
.lesson-meta { display: flex; gap: 16px; align-items: center; margin-bottom: 12px; flex-wrap: wrap; }
.lesson-level { display: inline-flex; align-items: center; gap: 6px; padding: 4px 12px; border-radius: 20px; font-size: 12px; font-weight: 600; }
.lesson-level.beginner { background: #E8F5E9; color: #2E7D32; }
.lesson-level.intermediate { background: #FFF3E0; color: #E65100; }
.lesson-level.advanced { background: #FCE4EC; color: #C2185B; }
.lesson-level.practice { background: #E3F2FD; color: #1565C0; }
.lesson-time { color: var(--text-light); font-size: 14px; display: flex; align-items: center; gap: 6px; }
.lesson h1 { font-size: 36px; color: var(--dark); margin-bottom: 16px; line-height: 1.3; }
.lesson h2 { font-size: 28px; color: var(--dark); margin-top: 48px; margin-bottom: 16px; padding-bottom: 8px; border-bottom: 2px solid var(--primary); }
.lesson h3 { font-size: 22px; color: var(--dark); margin-top: 32px; margin-bottom: 12px; }
.lesson p { margin-bottom: 16px; line-height: 1.8; }
.lesson ul, .lesson ol { margin-bottom: 16px; padding-left: 24px; }
.lesson li { margin-bottom: 8px; line-height: 1.7; }
.lesson li strong { color: var(--dark); }
.lesson-nav { display: flex; justify-content: space-between; gap: 16px; margin-top: 64px; padding-top: 32px; border-top: 1px solid var(--border); align-items: center; flex-wrap: wrap; }
.nav-btn { display: inline-flex; align-items: center; gap: 8px; padding: 12px 24px; background: var(--dark); color: white; border-radius: 4px; font-weight: 600; transition: all 0.2s; border: none; cursor: pointer; font-size: 15px; text-decoration: none; }
.nav-btn:hover { background: var(--primary); transform: translateY(-2px); box-shadow: 0 4px 12px rgba(4,170,109,0.3); }
.nav-btn.secondary { background: var(--bg-alt); color: var(--text); border: 1px solid var(--border); }
.nav-btn.secondary:hover { background: var(--border); transform: none; box-shadow: none; }
.mark-complete-btn { display: inline-flex; align-items: center; gap: 8px; padding: 12px 24px; border-radius: 4px; font-weight: 600; font-size: 15px; border: 2px solid var(--primary); background: none; color: var(--primary); cursor: pointer; transition: all 0.2s; }
.mark-complete-btn:hover { background: var(--primary); color: white; }
.mark-complete-btn.is-complete { background: var(--primary); color: white; }

/* NOTE BOXES */
.note { padding: 16px 20px; margin: 24px 0; border-radius: 4px; border-left: 4px solid; }
.note-title { font-weight: 600; margin-bottom: 8px; display: flex; align-items: center; gap: 8px; }
.note.info { background: #E3F2FD; border-color: var(--blue); color: #0D47A1; }
.note.tip { background: #E8F5E9; border-color: var(--primary); color: #1B5E20; }
.note.warning { background: #FFF3E0; border-color: var(--orange); color: #E65100; }
.note.important { background: #FCE4EC; border-color: var(--red); color: #B71C1C; }

/* CODE BLOCKS */
.example { margin: 24px 0; }
.example-header { background: var(--dark); color: white; padding: 12px 20px; font-size: 14px; font-weight: 600; border-radius: 4px 4px 0 0; display: flex; align-items: center; gap: 8px; }
.example-code { background: var(--dark-bg); color: #E0E0E0; padding: 20px; border-radius: 0 0 4px 4px; overflow-x: auto; font-size: 14px; line-height: 1.6; }
.example-code code { color: inherit; white-space: pre; }
.lesson-body .example-code code { color: inherit; background: none; padding: 0; border-radius: 0; font-size: inherit; }
.example.tryit .example-header { background: var(--primary); }
.code-comment { color: #6A9955; }
.code-keyword { color: #569CD6; }
.code-string { color: #CE9178; }
.code-function { color: #DCDCAA; }
.code-number { color: #B5CEA8; }

/* RESOURCE CARDS */
.resources { display: grid; gap: 12px; margin: 24px 0; }
.resource-card { display: flex; align-items: center; gap: 16px; padding: 16px; border: 1px solid var(--border); border-radius: 4px; text-decoration: none; color: var(--text); transition: all 0.2s; background: var(--bg); }
.resource-card:hover { border-color: var(--primary); box-shadow: 0 2px 8px rgba(4,170,109,0.15); transform: translateX(4px); }
.resource-icon { width: 48px; height: 48px; background: var(--primary-light); border-radius: 4px; display: grid; place-items: center; font-size: 20px; flex-shrink: 0; }
.resource-content { flex: 1; }
.resource-type { font-size: 11px; text-transform: uppercase; letter-spacing: 0.5px; color: var(--primary); font-weight: 600; margin-bottom: 4px; }
.resource-title { font-weight: 600; color: var(--dark); margin-bottom: 2px; }
.resource-arrow { color: var(--text-light); font-size: 20px; }

/* CHAPTER PAGE */
.chapter-page {}
.chapter-hero { background: linear-gradient(135deg, var(--dark) 0%, #1a4d3f 100%); color: white; padding: 48px 24px; }
.chapter-hero-content { max-width: 800px; margin: 0 auto; }
.chapter-hero-content p { opacity: 0.85; font-size: 16px; margin-top: 12px; }
.back-link { color: rgba(255,255,255,0.7); text-decoration: none; font-size: 14px; display: inline-block; margin-bottom: 16px; }
.back-link:hover { color: white; }
.chapter-tag { font-size: 13px; text-transform: uppercase; letter-spacing: 1px; color: var(--primary); margin-bottom: 8px; }
.chapter-hero h1 { font-size: 36px; font-weight: 700; margin-bottom: 12px; }
.chapter-hero-meta { display: flex; gap: 16px; align-items: center; flex-wrap: wrap; }
.chapter-content { max-width: 900px; margin: 0 auto; padding: 48px 24px; }
.lessons-section h2, .quiz-section h2 { font-size: 24px; margin-bottom: 16px; color: var(--dark); }

.lesson-cards { display: flex; flex-direction: column; gap: 12px; margin-bottom: 48px; }
.lesson-card { display: flex; align-items: center; gap: 16px; padding: 20px; border: 1px solid var(--border); border-radius: 6px; text-decoration: none; color: var(--text); transition: all 0.2s; background: var(--bg); }
.lesson-card:hover { border-color: var(--primary); box-shadow: 0 2px 8px rgba(4,170,109,0.15); transform: translateX(4px); }
.lesson-card.completed { border-color: var(--primary); background: var(--primary-light); }
.lesson-card-num { width: 36px; height: 36px; background: var(--primary-light); color: var(--primary-dark); border-radius: 50%; display: grid; place-items: center; font-weight: 700; flex-shrink: 0; transition: all 0.2s; }
.lesson-card-num.completed { background: var(--primary); color: #fff; }
.lesson-card-body { flex: 1; }
.lesson-card-body h3 { font-size: 16px; margin-bottom: 4px; }
.lesson-card-meta { display: flex; gap: 8px; align-items: center; }
.level-badge-sm { font-size: 11px; padding: 2px 8px; border-radius: 3px; font-weight: 600; }
.level-badge-sm.beginner { background: #E8F5E9; color: #2E7D32; }
.level-badge-sm.intermediate { background: #FFF3E0; color: #E65100; }
.level-badge-sm.advanced { background: #FCE4EC; color: #C2185B; }
.level-badge-sm.practice { background: #E3F2FD; color: #1565C0; }
.lesson-card-status { font-size: 18px; color: var(--text-light); }
.lesson-card-status.done { color: var(--primary); }

/* QUIZ SECTION */
.quiz-section { border-top: 2px solid var(--border); padding-top: 48px; }
.start-quiz-btn { background: var(--primary); color: white; border: none; padding: 14px 28px; border-radius: 6px; font-size: 16px; font-weight: 600; cursor: pointer; transition: background 0.2s; }
.start-quiz-btn:hover { background: var(--primary-dark); }
.quiz-header-row { display: flex; align-items: center; gap: 16px; margin-bottom: 20px; font-size: 14px; color: var(--text-light); }
.quiz-progress-bar { flex: 1; height: 6px; background: var(--border); border-radius: 3px; overflow: hidden; }
.quiz-progress-fill { height: 100%; background: var(--primary); transition: width 0.3s; }
.question-text { font-size: 20px; font-weight: 600; color: var(--dark); margin-bottom: 24px; line-height: 1.5; }
.quiz-options { display: flex; flex-direction: column; gap: 10px; margin-bottom: 20px; }
.quiz-option { display: flex; align-items: center; gap: 14px; padding: 14px 18px; border: 2px solid var(--border); border-radius: 6px; background: var(--bg); cursor: pointer; text-align: left; font-size: 15px; transition: all 0.15s; color: var(--text); width: 100%; }
.quiz-option:hover:not(.answered) { border-color: var(--primary); background: var(--primary-light); }
.quiz-option.correct { border-color: #2E7D32; background: #E8F5E9; color: #1B5E20; }
.quiz-option.wrong { border-color: var(--red); background: #FCE4EC; color: #B71C1C; }
.quiz-option.answered { cursor: default; }
.option-letter { width: 28px; height: 28px; border-radius: 50%; background: var(--bg-alt); display: grid; place-items: center; font-weight: 700; font-size: 13px; flex-shrink: 0; }
.quiz-option.correct .option-letter { background: #2E7D32; color: white; }
.quiz-option.wrong .option-letter { background: var(--red); color: white; }
.quiz-explanation { padding: 14px 18px; border-radius: 6px; margin-bottom: 16px; font-size: 14px; line-height: 1.6; }
.quiz-explanation.correct-exp { background: #E8F5E9; border-left: 4px solid #2E7D32; color: #1B5E20; }
.quiz-explanation.wrong-exp { background: #FCE4EC; border-left: 4px solid var(--red); color: #B71C1C; }
.quiz-next-btn { background: var(--dark); color: white; border: none; padding: 12px 24px; border-radius: 6px; font-size: 15px; font-weight: 600; cursor: pointer; }
.quiz-next-btn:hover { background: var(--primary); }
.quiz-result { text-align: center; padding: 40px 20px; }
.quiz-score-big { font-size: 64px; font-weight: 700; color: var(--primary); line-height: 1; }
.quiz-verdict { font-size: 24px; font-weight: 600; margin: 16px 0 8px; }
.quiz-verdict.pass { color: #2E7D32; }
.quiz-verdict.fail { color: var(--orange); }
.quiz-actions { display: flex; gap: 12px; justify-content: center; margin-top: 24px; flex-wrap: wrap; }
.btn-primary { background: var(--primary); color: white; border: none; padding: 12px 24px; border-radius: 6px; font-size: 15px; font-weight: 600; cursor: pointer; text-decoration: none; display: inline-block; transition: all 0.2s; }
.btn-primary:hover { background: var(--primary-dark); }
.btn-secondary { background: var(--bg-alt); color: var(--text); border: 1px solid var(--border); padding: 12px 24px; border-radius: 6px; font-size: 15px; font-weight: 600; cursor: pointer; transition: all 0.2s; }
.btn-secondary:hover { background: var(--border); }

/* CASE STUDIES */
.case-studies-hero { background: linear-gradient(135deg, var(--dark) 0%, #1a1a2e 100%); border-radius: 8px; padding: 48px; color: white; margin-bottom: 40px; }
.case-studies-hero h1 { font-size: 36px; font-weight: 700; margin-bottom: 12px; }
.case-studies-hero p { font-size: 17px; opacity: 0.85; max-width: 600px; }
.case-studies-list { max-width: 1100px; margin: 0 auto; padding: 48px 24px; }
.cs-grid { display: grid; grid-template-columns: repeat(2, 1fr); gap: 20px; }
.cs-card { border: 1px solid var(--border); border-radius: 8px; padding: 24px; background: white; transition: all 0.2s; }
.cs-card:hover { border-color: var(--primary); box-shadow: 0 4px 16px rgba(4,170,109,0.12); transform: translateY(-2px); }
.cs-card h3 { font-size: 18px; font-weight: 700; color: var(--dark); margin-bottom: 8px; }
.stat-chip { display: inline-flex; align-items: center; gap: 5px; padding: 3px 10px; border-radius: 20px; font-size: 12px; font-weight: 600; }
.stat-chip.amount { background: #FCE4EC; color: #C2185B; }
.stat-chip.type { background: #FFF3E0; color: #E65100; }
.stat-chip.date { background: #E3F2FD; color: #1565C0; }
.cs-chips { display: flex; gap: 8px; flex-wrap: wrap; margin-bottom: 16px; }
.cs-desc { font-size: 14px; color: var(--text-light); line-height: 1.6; margin-bottom: 16px; }
.cs-read-btn { display: inline-flex; align-items: center; gap: 6px; background: var(--dark); color: white; font-weight: 600; font-size: 14px; border: none; cursor: pointer; padding: 8px 16px; border-radius: 4px; text-decoration: none; transition: all 0.2s; }
.cs-read-btn:hover { background: var(--primary); }

/* CASE STUDY DETAIL */
.case-study-page {}
.cs-detail-hero { background: linear-gradient(135deg, #1a1a2e 0%, var(--dark) 100%); padding: 48px 24px; color: white; }
.cs-hero-content { max-width: 800px; margin: 0 auto; }
.cs-detail-hero h1 { font-size: 32px; font-weight: 700; margin: 16px 0; }
.cs-detail-chips { display: flex; gap: 10px; flex-wrap: wrap; margin-bottom: 16px; }
.cs-summary { font-size: 16px; opacity: 0.85; line-height: 1.7; }
.cs-back-btn { display: inline-flex; align-items: center; gap: 6px; color: rgba(255,255,255,0.75); font-weight: 600; font-size: 14px; background: none; border: none; cursor: pointer; padding: 0; margin-bottom: 16px; text-decoration: none; }
.cs-back-btn:hover { color: white; }
.case-study-view { max-width: 860px; margin: 0 auto; padding: 48px 24px; }
.cs-detail-content h2 { font-size: 24px; color: var(--dark); margin-top: 40px; margin-bottom: 16px; padding-bottom: 8px; border-bottom: 2px solid var(--primary); }
.cs-detail-content h3 { font-size: 19px; color: var(--dark); margin-top: 24px; margin-bottom: 10px; }
.cs-detail-content p { margin-bottom: 14px; line-height: 1.8; }
.cs-detail-content ul, .cs-detail-content ol { margin-bottom: 16px; padding-left: 24px; }
.cs-detail-content li { margin-bottom: 8px; line-height: 1.7; }
.cs-detail-content .note { padding: 16px 20px; margin: 20px 0; border-radius: 4px; border-left: 4px solid; }
.cs-detail-content .note.tip { background: #E8F5E9; border-color: var(--primary); color: #1B5E20; }
.cs-detail-content .note.important { background: #FCE4EC; border-color: var(--red); color: #B71C1C; }

/* FOOTER */
footer { background: var(--bg-alt); padding: 48px 24px; text-align: center; color: var(--text-light); border-top: 1px solid var(--border); margin-top: 64px; }
footer p { margin-bottom: 8px; }

/* ANIMATION */
@keyframes fadeIn { from { opacity: 0; transform: translateY(8px); } to { opacity: 1; transform: translateY(0); } }
.fade-in { animation: fadeIn 0.25s ease; }

/* === COMPARISON TABLE === */
.comparison-table {
  width: 100%;
  border-collapse: collapse;
  margin: 24px 0;
  font-size: 14px;
  border-radius: 6px;
  overflow: hidden;
}
.comparison-table th {
  background: var(--dark);
  color: white;
  padding: 12px 16px;
  text-align: left;
  font-weight: 600;
}
.comparison-table td {
  padding: 10px 16px;
  border-bottom: 1px solid var(--border);
  vertical-align: top;
  line-height: 1.6;
}
.comparison-table tr:nth-child(even) td { background: var(--bg-alt); }
.comparison-table tr:hover td { background: var(--primary-light); }
.comparison-table td code, .comparison-table th code {
  background: rgba(0,0,0,0.1);
  padding: 1px 6px;
  border-radius: 3px;
  font-family: 'Source Code Pro', monospace;
  font-size: 13px;
}

/* === LESSON BODY TYPOGRAPHY === */
.lesson-body h2 { font-size: 26px; color: var(--dark); margin-top: 48px; margin-bottom: 14px; padding-bottom: 8px; border-bottom: 2px solid var(--primary); }
.lesson-body h3 { font-size: 20px; color: var(--dark); margin-top: 28px; margin-bottom: 10px; }
.lesson-body p { margin-bottom: 14px; line-height: 1.8; }
.lesson-body ul, .lesson-body ol { padding-left: 22px; margin-bottom: 14px; }
.lesson-body li { margin-bottom: 6px; line-height: 1.7; }
.lesson-body li strong { color: var(--dark); }
.lesson-body code { background: rgba(0,0,0,0.06); padding: 2px 6px; border-radius: 3px; font-family: 'Source Code Pro', monospace; font-size: 0.9em; color: var(--dark); }

/* RESPONSIVE */
@media (max-width: 1024px) {
  .page-with-sidebar, .lesson-layout { grid-template-columns: 1fr; }
  .sidebar { position: static; height: auto; border-right: none; border-bottom: 1px solid var(--border); }
  .chapter-grid { grid-template-columns: 1fr; }
  .cs-grid { grid-template-columns: 1fr; }
}
@media (max-width: 768px) {
  .main-content { padding: 24px; }
  .hero h1 { font-size: 32px; }
  .hero p { font-size: 16px; }
  .hero-stats { gap: 24px; }
  .header-progress { display: none !important; }
  .chapter-hero { padding: 32px 16px; }
  .chapter-content { padding: 32px 16px; }
}
@media (max-width: 480px) {
  .chapter-grid { grid-template-columns: 1fr; }
  .lesson-nav { flex-direction: column; }
}