/* ===== Agile Workflow Training Course — Light Theme ===== */

:root {
  --bg-primary: #ffffff;
  --bg-secondary: #f8fafc;
  --bg-card: #ffffff;
  --bg-code: #f1f5f9;
  --bg-hero: linear-gradient(135deg, #0ea5e9 0%, #2563eb 50%, #7c3aed 100%);
  --text-primary: #0f172a;
  --text-secondary: #475569;
  --text-muted: #94a3b8;
  --accent: #2563eb;
  --accent-light: #3b82f6;
  --accent-bg: #eff6ff;
  --green: #059669;
  --green-bg: #ecfdf5;
  --yellow: #d97706;
  --yellow-bg: #fffbeb;
  --red: #dc2626;
  --red-bg: #fef2f2;
  --purple: #7c3aed;
  --purple-bg: #f5f3ff;
  --cyan: #0891b2;
  --pink: #db2777;
  --border: #e2e8f0;
  --border-hover: #cbd5e1;
  --shadow-sm: 0 1px 3px rgba(0,0,0,0.06), 0 1px 2px rgba(0,0,0,0.04);
  --shadow: 0 4px 16px rgba(0,0,0,0.06);
  --shadow-lg: 0 12px 40px rgba(0,0,0,0.1);
  --radius: 16px;
  --radius-sm: 10px;
  --radius-xs: 6px;
}

/* ===== Reset ===== */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
html { scroll-behavior: smooth; font-size: 16px; }
body {
  font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
  background: var(--bg-secondary);
  color: var(--text-primary);
  line-height: 1.75;
  min-height: 100vh;
  -webkit-font-smoothing: antialiased;
}
a { color: var(--accent); text-decoration: none; transition: all 0.2s; }
a:hover { color: var(--accent-light); }
img { max-width: 100%; display: block; }

/* ===== Typography ===== */
h1, h2, h3, h4 { line-height: 1.3; font-weight: 700; color: var(--text-primary); }
h1 { font-size: 2.25rem; margin-bottom: 0.75rem; letter-spacing: -0.02em; }
h2 { font-size: 1.6rem; margin: 3rem 0 1rem; letter-spacing: -0.01em; }
h3 { font-size: 1.2rem; margin: 2rem 0 0.75rem; color: var(--accent); font-weight: 600; }
h4 { font-size: 1.05rem; margin: 1.5rem 0 0.5rem; }
p { margin-bottom: 1rem; color: var(--text-secondary); }
strong { color: var(--text-primary); font-weight: 600; }
ul, ol { margin: 0.5rem 0 1rem 1.5rem; color: var(--text-secondary); }
li { margin-bottom: 0.35rem; }

/* ===== Layout ===== */
.container { max-width: 820px; margin: 0 auto; padding: 2rem 1.5rem; }

/* ===== Nav ===== */
.nav {
  display: flex; justify-content: space-between; align-items: center;
  padding: 0.75rem 2rem;
  background: #fff;
  border-bottom: 1px solid var(--border);
  position: sticky; top: 0; z-index: 100;
}
.nav-brand {
  font-weight: 700; font-size: 1rem; color: var(--text-primary);
  display: flex; align-items: center; gap: 0.5rem;
}
.nav-links { display: flex; gap: 1.25rem; }
.nav-links a { color: var(--text-muted); font-size: 0.875rem; font-weight: 500; }
.nav-links a:hover { color: var(--accent); }

/* ===== Hero ===== */
.hero {
  text-align: center;
  padding: 3.5rem 2rem 3rem;
  background: var(--bg-hero);
  border-radius: var(--radius);
  margin-bottom: 2.5rem;
  position: relative; overflow: hidden;
}
.hero::before {
  content: ''; position: absolute; inset: 0;
  background: url("data:image/svg+xml,%3Csvg width='60' height='60' viewBox='0 0 60 60' xmlns='http://www.w3.org/2000/svg'%3E%3Cg fill='none' fill-rule='evenodd'%3E%3Cg fill='%23ffffff' fill-opacity='0.05'%3E%3Cpath d='M36 34v-4h-2v4h-4v2h4v4h2v-4h4v-2h-4zm0-30V0h-2v4h-4v2h4v4h2V6h4V4h-4zM6 34v-4H4v4H0v2h4v4h2v-4h4v-2H6zM6 4V0H4v4H0v2h4v4h2V6h4V4H6z'/%3E%3C/g%3E%3C/g%3E%3C/svg%3E");
}
.hero h1 { color: #fff; font-size: 2.5rem; position: relative; z-index: 1; letter-spacing: -0.03em; }
.hero p { color: rgba(255,255,255,0.9); font-size: 1.1rem; position: relative; z-index: 1; margin-bottom: 0.25rem; }
.hero .subtitle { font-size: 0.9rem; color: rgba(255,255,255,0.7); }
.hero .lesson-number {
  display: inline-block; padding: 0.25rem 0.75rem; border-radius: 20px;
  background: rgba(255,255,255,0.2); color: #fff; font-size: 0.8rem;
  font-weight: 600; letter-spacing: 0.05em; margin-bottom: 0.75rem;
  position: relative; z-index: 1;
}

/* ===== Cards ===== */
.card {
  background: var(--bg-card); border: 1px solid var(--border);
  border-radius: var(--radius-sm); padding: 1.5rem;
  margin-bottom: 1.25rem; box-shadow: var(--shadow-sm);
  transition: all 0.2s;
}
.card:hover { box-shadow: var(--shadow); border-color: var(--border-hover); }
.card-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(260px, 1fr)); gap: 1rem; margin: 1.5rem 0; }

/* ===== Module Cards (index page) ===== */
.module-card {
  background: #fff; border: 1px solid var(--border);
  border-radius: var(--radius-sm); padding: 1.25rem 1.5rem;
  display: block; text-decoration: none;
  box-shadow: var(--shadow-sm); transition: all 0.25s;
}
.module-card:hover { box-shadow: var(--shadow-lg); transform: translateY(-3px); border-color: var(--accent); }
.module-card .module-number { font-size: 0.7rem; font-weight: 700; text-transform: uppercase; letter-spacing: 0.08em; color: var(--text-muted); }
.module-card .module-title { font-size: 1.05rem; font-weight: 700; color: var(--text-primary); margin: 0.35rem 0; }
.module-card .module-desc { font-size: 0.85rem; color: var(--text-secondary); line-height: 1.5; }
.module-card .module-badge {
  display: inline-block; padding: 0.15rem 0.6rem; border-radius: 20px;
  font-size: 0.65rem; font-weight: 700; letter-spacing: 0.03em; margin-top: 0.65rem;
}
.badge-fundamentals { background: var(--accent-bg); color: var(--accent); }
.badge-scrum { background: #ecfeff; color: var(--cyan); }
.badge-engineering { background: var(--green-bg); color: var(--green); }
.badge-advanced { background: var(--purple-bg); color: var(--purple); }
.badge-ai { background: #fdf2f8; color: var(--pink); }
.badge-tutorial { background: #fff7ed; color: var(--yellow); }

/* ===== Flow Diagrams (HTML/CSS) ===== */
.flow { display: flex; align-items: stretch; gap: 0; margin: 2rem 0; flex-wrap: wrap; justify-content: center; }
.flow-step {
  background: #fff; border: 2px solid var(--border); border-radius: var(--radius-sm);
  padding: 1rem 1.25rem; min-width: 140px; text-align: center;
  font-size: 0.85rem; font-weight: 600; color: var(--text-primary);
  display: flex; flex-direction: column; align-items: center; justify-content: center;
  box-shadow: var(--shadow-sm);
}
.flow-step small { font-weight: 400; color: var(--text-muted); font-size: 0.75rem; display: block; margin-top: 0.25rem; }
.flow-step .step-icon { font-size: 1.5rem; margin-bottom: 0.35rem; }
.flow-arrow {
  display: flex; align-items: center; justify-content: center;
  padding: 0 0.5rem; color: var(--accent); font-size: 1.25rem; font-weight: 700;
}
.flow-arrow::after { content: '→'; }

/* Vertical flow */
.flow-v { flex-direction: column; align-items: center; }
.flow-v .flow-arrow { padding: 0.35rem 0; transform: rotate(90deg); }

/* Colored steps */
.flow-step.blue { border-color: var(--accent); background: var(--accent-bg); }
.flow-step.green { border-color: var(--green); background: var(--green-bg); }
.flow-step.yellow { border-color: var(--yellow); background: var(--yellow-bg); }
.flow-step.red { border-color: var(--red); background: var(--red-bg); }
.flow-step.purple { border-color: var(--purple); background: var(--purple-bg); }

/* Cycle diagram */
.cycle {
  display: flex; justify-content: center; align-items: center;
  gap: 1rem; margin: 2rem auto; flex-wrap: wrap; max-width: 500px;
}
.cycle-step {
  width: 120px; height: 120px; border-radius: 50%;
  display: flex; flex-direction: column; align-items: center; justify-content: center;
  font-weight: 700; font-size: 0.85rem; text-align: center;
  box-shadow: var(--shadow-sm); border: 3px solid;
}
.cycle-step .step-icon { font-size: 1.5rem; margin-bottom: 0.25rem; }
.cycle-step.red-step { border-color: var(--red); background: var(--red-bg); color: var(--red); }
.cycle-step.green-step { border-color: var(--green); background: var(--green-bg); color: var(--green); }
.cycle-step.blue-step { border-color: var(--accent); background: var(--accent-bg); color: var(--accent); }
.cycle-arrow { font-size: 1.5rem; color: var(--text-muted); }

/* Track cards */
.track-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(200px, 1fr)); gap: 1.25rem; margin: 2rem 0; }
.track-card {
  background: #fff; border: 1px solid var(--border); border-radius: var(--radius-sm);
  padding: 1.25rem; box-shadow: var(--shadow-sm); border-top: 4px solid;
}
.track-card h4 { margin: 0 0 0.75rem; font-size: 0.95rem; }
.track-card ul { margin: 0; padding: 0; list-style: none; }
.track-card li { padding: 0.3rem 0; font-size: 0.85rem; color: var(--text-secondary); }
.track-card li a { color: var(--text-secondary); }
.track-card li a:hover { color: var(--accent); }
.track-card.t1 { border-top-color: var(--accent); }
.track-card.t2 { border-top-color: var(--cyan); }
.track-card.t3 { border-top-color: var(--green); }
.track-card.t4 { border-top-color: var(--purple); }

/* ===== Code Blocks ===== */
pre {
  background: var(--bg-code); border: 1px solid var(--border);
  border-radius: var(--radius-xs); padding: 1.25rem;
  overflow-x: auto; margin: 1.25rem 0; font-size: 0.875rem; line-height: 1.65;
  position: relative;
}
code {
  font-family: 'JetBrains Mono', 'Fira Code', monospace; font-size: 0.85em;
}
:not(pre) > code {
  background: var(--bg-code); padding: 0.15rem 0.4rem;
  border-radius: var(--radius-xs); color: var(--accent);
  border: 1px solid var(--border); font-size: 0.85em;
}
.code-label {
  display: inline-block; background: var(--accent); color: #fff;
  padding: 0.15rem 0.6rem; border-radius: var(--radius-xs) var(--radius-xs) 0 0;
  font-size: 0.7rem; font-weight: 600; letter-spacing: 0.03em; margin-bottom: -1px;
}
.code-bad { border-left: 3px solid var(--red); }
.code-good { border-left: 3px solid var(--green); }

/* ===== Callouts ===== */
.callout {
  border-radius: var(--radius-sm); padding: 1rem 1.25rem; margin: 1.5rem 0;
  border-left: 4px solid; background: #fff;
}
.callout-title { font-weight: 700; font-size: 0.85rem; margin-bottom: 0.35rem; display: flex; align-items: center; gap: 0.4rem; }
.callout p { margin-bottom: 0.35rem; font-size: 0.9rem; }
.callout-info { border-color: var(--accent); background: var(--accent-bg); }
.callout-info .callout-title { color: var(--accent); }
.callout-success { border-color: var(--green); background: var(--green-bg); }
.callout-success .callout-title { color: var(--green); }
.callout-warning { border-color: var(--yellow); background: var(--yellow-bg); }
.callout-warning .callout-title { color: var(--yellow); }
.callout-danger { border-color: var(--red); background: var(--red-bg); }
.callout-danger .callout-title { color: var(--red); }

/* ===== Tables ===== */
table { width: 100%; border-collapse: collapse; margin: 1.25rem 0; font-size: 0.875rem; }
th, td { padding: 0.65rem 1rem; text-align: left; border-bottom: 1px solid var(--border); }
th { background: var(--bg-secondary); font-weight: 600; color: var(--text-primary); font-size: 0.75rem; text-transform: uppercase; letter-spacing: 0.04em; }
td { color: var(--text-secondary); }
tr:hover td { background: var(--accent-bg); }

/* ===== Quizzes ===== */
.quiz { background: #fff; border: 1px solid var(--border); border-radius: var(--radius-sm); padding: 1.5rem; margin: 2rem 0; box-shadow: var(--shadow-sm); }
.quiz h3 { color: var(--purple); margin-top: 0; font-size: 1.05rem; }
.quiz-option {
  display: block; width: 100%; text-align: left;
  padding: 0.7rem 1rem; margin: 0.4rem 0;
  background: var(--bg-secondary); border: 1.5px solid var(--border);
  border-radius: var(--radius-xs); color: var(--text-secondary);
  cursor: pointer; transition: all 0.15s; font-size: 0.9rem; font-family: inherit;
}
.quiz-option:hover { border-color: var(--accent); color: var(--text-primary); background: var(--accent-bg); }
.quiz-option.correct { border-color: var(--green); background: var(--green-bg); color: var(--green); font-weight: 600; }
.quiz-option.incorrect { border-color: var(--red); background: var(--red-bg); color: var(--red); }
.quiz-feedback { margin-top: 0.75rem; padding: 0.65rem 1rem; border-radius: var(--radius-xs); font-size: 0.875rem; display: none; }
.quiz-feedback.show { display: block; }
.quiz-feedback.correct { background: var(--green-bg); color: var(--green); }
.quiz-feedback.incorrect { background: var(--red-bg); color: var(--red); }

/* ===== Progress ===== */
.progress-bar { width: 100%; height: 6px; background: var(--border); border-radius: 3px; margin: 1rem 0 0.5rem; overflow: hidden; }
.progress-fill { height: 100%; background: var(--bg-hero); border-radius: 3px; transition: width 0.5s; }

/* ===== Lesson Nav ===== */
.lesson-nav { display: flex; justify-content: space-between; margin-top: 3rem; padding-top: 2rem; border-top: 1px solid var(--border); }
.lesson-nav a {
  display: inline-flex; align-items: center; gap: 0.4rem;
  padding: 0.6rem 1.1rem; background: #fff; border: 1px solid var(--border);
  border-radius: var(--radius-xs); color: var(--text-secondary); font-size: 0.875rem;
  box-shadow: var(--shadow-sm); transition: all 0.2s;
}
.lesson-nav a:hover { border-color: var(--accent); color: var(--accent); box-shadow: var(--shadow); }
.lesson-nav .next { margin-left: auto; }

/* ===== Tags ===== */
.concepts { display: flex; flex-wrap: wrap; gap: 0.4rem; margin: 0.75rem 0; }
.concept-tag { padding: 0.2rem 0.65rem; background: var(--accent-bg); border-radius: 20px; font-size: 0.75rem; color: var(--accent); font-weight: 500; }

/* ===== Emoji List ===== */
.emoji-list { list-style: none; padding: 0; }
.emoji-list li { padding: 0.4rem 0; color: var(--text-secondary); display: flex; gap: 0.6rem; align-items: flex-start; }

/* ===== Tabs ===== */
.tabs { margin: 1.5rem 0; background: #fff; border: 1px solid var(--border); border-radius: var(--radius-sm); overflow: hidden; }
.tab-buttons { display: flex; background: var(--bg-secondary); border-bottom: 1px solid var(--border); }
.tab-btn {
  padding: 0.65rem 1.25rem; background: none; border: none;
  color: var(--text-muted); font-size: 0.85rem; font-family: inherit;
  cursor: pointer; font-weight: 500; transition: all 0.2s;
  border-bottom: 2px solid transparent; margin-bottom: -1px;
}
.tab-btn:hover { color: var(--text-primary); }
.tab-btn.active { color: var(--accent); border-bottom-color: var(--accent); background: #fff; }
.tab-content { display: none; padding: 1.25rem; }
.tab-content.active { display: block; }

/* ===== Comparison (Good/Bad) ===== */
.compare { display: grid; grid-template-columns: 1fr 1fr; gap: 1rem; margin: 1.5rem 0; }
.compare-bad, .compare-good { border-radius: var(--radius-xs); padding: 1rem; }
.compare-bad { background: var(--red-bg); border: 1px solid #fecaca; }
.compare-good { background: var(--green-bg); border: 1px solid #a7f3d0; }
.compare-label { font-size: 0.75rem; font-weight: 700; margin-bottom: 0.5rem; display: flex; align-items: center; gap: 0.35rem; }
.compare-bad .compare-label { color: var(--red); }
.compare-good .compare-label { color: var(--green); }

/* ===== Responsive ===== */
@media (max-width: 768px) {
  .container { padding: 1rem; }
  .hero { padding: 2.5rem 1.25rem; }
  .hero h1 { font-size: 1.75rem; }
  h1 { font-size: 1.75rem; }
  .card-grid { grid-template-columns: 1fr; }
  .track-grid { grid-template-columns: 1fr 1fr; }
  .flow { flex-direction: column; align-items: center; }
  .flow-arrow { transform: rotate(90deg); }
  .lesson-nav { flex-direction: column; gap: 0.75rem; }
  .compare { grid-template-columns: 1fr; }
  .cycle { flex-direction: column; }
}
@media (max-width: 480px) {
  .track-grid { grid-template-columns: 1fr; }
}

/* ===== Animations ===== */
@keyframes fadeUp { from { opacity: 0; transform: translateY(12px); } to { opacity: 1; transform: translateY(0); } }
.fade-in { animation: fadeUp 0.4s ease forwards; }