/* ===== ISTQB CTFL Study Site - Styles ===== */

:root {
  --primary: #4f46e5;
  --primary-light: #818cf8;
  --primary-dark: #3730a3;
  --success: #059669;
  --danger: #dc2626;
  --warning: #d97706;
  --info: #0891b2;
  --bg: #f8fafc;
  --card-bg: #ffffff;
  --text: #1e293b;
  --text-muted: #64748b;
  --border: #e2e8f0;
  --border-radius: 12px;
  --shadow: 0 1px 3px rgba(0,0,0,0.1), 0 1px 2px rgba(0,0,0,0.06);
  --shadow-md: 0 4px 6px -1px rgba(0,0,0,0.1), 0 2px 4px -1px rgba(0,0,0,0.06);
  --shadow-lg: 0 10px 15px -3px rgba(0,0,0,0.1), 0 4px 6px -2px rgba(0,0,0,0.05);
}

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

body {
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
  background: var(--bg);
  color: var(--text);
  line-height: 1.6;
  min-height: 100vh;
}

/* ===== HEADER ===== */
header {
  background: linear-gradient(135deg, #4f46e5 0%, #7c3aed 100%);
  color: white;
  padding: 16px 24px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  box-shadow: var(--shadow-md);
  position: sticky;
  top: 0;
  z-index: 100;
}

.header-brand {
  display: flex;
  align-items: center;
  gap: 12px;
  cursor: pointer;
}

.header-logo {
  background: rgba(255,255,255,0.2);
  border-radius: 10px;
  width: 40px;
  height: 40px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 20px;
}

.header-title { font-size: 20px; font-weight: 700; letter-spacing: -0.3px; }
.header-subtitle { font-size: 12px; opacity: 0.8; }

nav {
  display: flex;
  gap: 4px;
}

.nav-btn {
  background: rgba(255,255,255,0.15);
  border: 1px solid rgba(255,255,255,0.25);
  color: white;
  padding: 8px 16px;
  border-radius: 8px;
  cursor: pointer;
  font-size: 14px;
  font-weight: 500;
  transition: all 0.2s;
}

.nav-btn:hover, .nav-btn.active {
  background: rgba(255,255,255,0.3);
  border-color: rgba(255,255,255,0.5);
}

/* ===== LAYOUT ===== */
main {
  max-width: 1200px;
  margin: 0 auto;
  padding: 24px 20px;
}

.page { display: none; }
.page.active { display: block; }

/* ===== CARDS ===== */
.card {
  background: var(--card-bg);
  border-radius: var(--border-radius);
  padding: 24px;
  box-shadow: var(--shadow);
  border: 1px solid var(--border);
  margin-bottom: 20px;
}

.card-sm { padding: 16px; }

/* ===== HOME PAGE ===== */
.hero {
  background: linear-gradient(135deg, #4f46e5 0%, #7c3aed 100%);
  color: white;
  border-radius: 16px;
  padding: 48px 40px;
  margin-bottom: 32px;
  position: relative;
  overflow: hidden;
}

.hero::before {
  content: '';
  position: absolute;
  right: -60px;
  top: -60px;
  width: 240px;
  height: 240px;
  background: rgba(255,255,255,0.08);
  border-radius: 50%;
}

.hero::after {
  content: '';
  position: absolute;
  right: 60px;
  bottom: -80px;
  width: 180px;
  height: 180px;
  background: rgba(255,255,255,0.05);
  border-radius: 50%;
}

.hero h1 { font-size: 32px; font-weight: 800; margin-bottom: 8px; }
.hero p { font-size: 16px; opacity: 0.9; max-width: 600px; }

.hero-stats {
  display: flex;
  gap: 32px;
  margin-top: 24px;
  flex-wrap: wrap;
}

.hero-stat {
  text-align: center;
  background: rgba(255,255,255,0.15);
  border-radius: 12px;
  padding: 16px 24px;
}

.hero-stat .number { font-size: 28px; font-weight: 800; }
.hero-stat .label { font-size: 12px; opacity: 0.8; text-transform: uppercase; letter-spacing: 0.5px; }

.grid-3 {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 20px;
  margin-bottom: 32px;
}

.grid-2 {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(340px, 1fr));
  gap: 20px;
}

.quick-action-card {
  background: var(--card-bg);
  border-radius: var(--border-radius);
  padding: 24px;
  box-shadow: var(--shadow);
  border: 1px solid var(--border);
  cursor: pointer;
  transition: all 0.2s;
  text-align: center;
}

.quick-action-card:hover {
  transform: translateY(-2px);
  box-shadow: var(--shadow-lg);
  border-color: var(--primary-light);
}

.quick-action-icon {
  font-size: 36px;
  margin-bottom: 12px;
}

.quick-action-card h3 { font-size: 16px; font-weight: 700; margin-bottom: 6px; }
.quick-action-card p { font-size: 14px; color: var(--text-muted); }

.chapter-card {
  background: var(--card-bg);
  border-radius: var(--border-radius);
  padding: 20px;
  box-shadow: var(--shadow);
  border: 1px solid var(--border);
  cursor: pointer;
  transition: all 0.2s;
  border-left: 4px solid transparent;
}

.chapter-card:hover {
  transform: translateY(-1px);
  box-shadow: var(--shadow-md);
}

.chapter-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 8px;
}

.chapter-num {
  font-size: 12px;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.5px;
  opacity: 0.7;
}

.chapter-badge {
  font-size: 12px;
  padding: 3px 10px;
  border-radius: 20px;
  font-weight: 600;
}

.chapter-card h3 { font-size: 16px; font-weight: 700; margin-bottom: 6px; }
.chapter-card p { font-size: 13px; color: var(--text-muted); }

.chapter-meta {
  display: flex;
  gap: 16px;
  margin-top: 12px;
  font-size: 12px;
  color: var(--text-muted);
}

/* ===== SYLLABUS PAGE ===== */
.page-header {
  margin-bottom: 24px;
}

.page-header h2 { font-size: 28px; font-weight: 800; }
.page-header p { color: var(--text-muted); margin-top: 4px; }

.chapter-tabs {
  display: flex;
  gap: 8px;
  flex-wrap: wrap;
  margin-bottom: 24px;
}

.chapter-tab {
  padding: 8px 18px;
  border-radius: 8px;
  border: 2px solid var(--border);
  background: white;
  cursor: pointer;
  font-size: 14px;
  font-weight: 500;
  transition: all 0.2s;
}

.chapter-tab:hover { border-color: var(--primary-light); }
.chapter-tab.active {
  background: var(--primary);
  color: white;
  border-color: var(--primary);
}

.section-content {
  background: var(--card-bg);
  border-radius: var(--border-radius);
  border: 1px solid var(--border);
  overflow: hidden;
  margin-bottom: 16px;
}

.section-header {
  padding: 16px 20px;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: space-between;
  font-weight: 600;
  font-size: 15px;
  border-bottom: 1px solid transparent;
  transition: all 0.2s;
  background: white;
}

.section-header:hover { background: #f8fafc; }
.section-header.open { border-bottom-color: var(--border); }

.section-body {
  padding: 20px;
  display: none;
  white-space: pre-wrap;
  font-size: 14px;
  line-height: 1.8;
  background: #fafbff;
}

.section-body.open { display: block; }

.key-terms {
  margin-top: 16px;
  padding-top: 16px;
  border-top: 1px solid var(--border);
}

.key-terms-title { font-size: 12px; font-weight: 700; text-transform: uppercase; color: var(--text-muted); margin-bottom: 8px; }

.term-tag {
  display: inline-block;
  background: #ede9fe;
  color: #5b21b6;
  padding: 3px 10px;
  border-radius: 20px;
  font-size: 12px;
  font-weight: 500;
  margin: 3px;
}

.lo-table {
  width: 100%;
  border-collapse: collapse;
  font-size: 13px;
  margin-top: 16px;
}

.lo-table th {
  background: #f1f5f9;
  padding: 10px 12px;
  text-align: left;
  font-weight: 600;
  font-size: 12px;
  text-transform: uppercase;
  letter-spacing: 0.3px;
  border-bottom: 2px solid var(--border);
}

.lo-table td { padding: 10px 12px; border-bottom: 1px solid var(--border); }
.lo-table tr:hover td { background: #f8fafc; }

.k-badge {
  display: inline-block;
  padding: 2px 8px;
  border-radius: 4px;
  font-weight: 700;
  font-size: 11px;
}

.k1 { background: #dcfce7; color: #166534; }
.k2 { background: #dbeafe; color: #1e40af; }
.k3 { background: #fef3c7; color: #92400e; }

/* ===== QUIZ / PRACTICE PAGE ===== */
.quiz-controls {
  display: flex;
  gap: 12px;
  flex-wrap: wrap;
  margin-bottom: 24px;
  align-items: center;
}

.quiz-controls select, .quiz-controls input {
  padding: 10px 14px;
  border: 2px solid var(--border);
  border-radius: 8px;
  font-size: 14px;
  background: white;
  outline: none;
  transition: border-color 0.2s;
}

.quiz-controls select:focus, .quiz-controls input:focus {
  border-color: var(--primary);
}

.btn {
  padding: 10px 20px;
  border-radius: 8px;
  border: none;
  font-size: 14px;
  font-weight: 600;
  cursor: pointer;
  transition: all 0.2s;
  display: inline-flex;
  align-items: center;
  gap: 6px;
}

.btn-primary {
  background: var(--primary);
  color: white;
}

.btn-primary:hover { background: var(--primary-dark); transform: translateY(-1px); }

.btn-success {
  background: var(--success);
  color: white;
}

.btn-success:hover { background: #047857; }

.btn-outline {
  background: white;
  color: var(--primary);
  border: 2px solid var(--primary);
}

.btn-outline:hover { background: #ede9fe; }

.btn-danger {
  background: var(--danger);
  color: white;
}

.btn-sm { padding: 6px 14px; font-size: 13px; }

/* Quiz Card */
.quiz-card {
  background: white;
  border-radius: 16px;
  padding: 32px;
  box-shadow: var(--shadow-lg);
  border: 1px solid var(--border);
}

.quiz-progress-bar {
  background: #e2e8f0;
  border-radius: 4px;
  height: 6px;
  margin-bottom: 20px;
  overflow: hidden;
}

.quiz-progress-fill {
  background: linear-gradient(90deg, var(--primary), var(--primary-light));
  height: 100%;
  transition: width 0.3s ease;
  border-radius: 4px;
}

.quiz-meta {
  display: flex;
  justify-content: space-between;
  margin-bottom: 24px;
  font-size: 13px;
  color: var(--text-muted);
  align-items: center;
}

.quiz-meta-badges { display: flex; gap: 8px; }

.badge {
  display: inline-block;
  padding: 3px 10px;
  border-radius: 20px;
  font-size: 12px;
  font-weight: 600;
}

.badge-chapter { background: #ede9fe; color: #5b21b6; }
.badge-lo { background: #dbeafe; color: #1e40af; }
.badge-source { background: #fef3c7; color: #92400e; }

.question-text {
  font-size: 18px;
  font-weight: 600;
  line-height: 1.6;
  margin-bottom: 28px;
  color: var(--text);
}

.options-list {
  display: flex;
  flex-direction: column;
  gap: 12px;
  margin-bottom: 24px;
}

.option-btn {
  display: flex;
  align-items: flex-start;
  gap: 14px;
  padding: 16px 20px;
  border: 2px solid var(--border);
  border-radius: 10px;
  cursor: pointer;
  text-align: left;
  background: white;
  font-size: 15px;
  transition: all 0.2s;
  width: 100%;
}

.option-btn:hover:not(:disabled) {
  border-color: var(--primary-light);
  background: #f5f3ff;
}

.option-btn:disabled { cursor: default; }

.option-letter {
  width: 28px;
  height: 28px;
  border-radius: 50%;
  background: #f1f5f9;
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 700;
  font-size: 13px;
  flex-shrink: 0;
  margin-top: 2px;
  transition: all 0.2s;
}

.option-btn.correct {
  border-color: var(--success);
  background: #f0fdf4;
}

.option-btn.correct .option-letter {
  background: var(--success);
  color: white;
}

.option-btn.incorrect {
  border-color: var(--danger);
  background: #fef2f2;
}

.option-btn.incorrect .option-letter {
  background: var(--danger);
  color: white;
}

.option-btn.selected-multi {
  border-color: var(--primary);
  background: #f5f3ff;
}

.option-btn.selected-multi .option-letter {
  background: var(--primary);
  color: white;
}

.explanation-box {
  background: #f0fdf4;
  border: 1px solid #bbf7d0;
  border-radius: 10px;
  padding: 16px 20px;
  margin-top: 16px;
  font-size: 14px;
  line-height: 1.7;
  display: none;
}

.explanation-box.incorrect-bg {
  background: #fef2f2;
  border-color: #fecaca;
}

.explanation-box .exp-label {
  font-weight: 700;
  margin-bottom: 6px;
  display: flex;
  align-items: center;
  gap: 6px;
}

.quiz-nav {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-top: 24px;
  padding-top: 20px;
  border-top: 1px solid var(--border);
}

.score-tracker {
  display: flex;
  gap: 20px;
  font-size: 14px;
}

.score-item { display: flex; align-items: center; gap: 6px; font-weight: 600; }
.score-correct { color: var(--success); }
.score-incorrect { color: var(--danger); }

/* Results */
.results-card {
  text-align: center;
  padding: 48px 32px;
}

.results-score {
  font-size: 72px;
  font-weight: 900;
  line-height: 1;
  margin-bottom: 8px;
}

.results-pass { color: var(--success); }
.results-fail { color: var(--danger); }

.results-message {
  font-size: 20px;
  font-weight: 600;
  margin-bottom: 8px;
}

.results-detail { color: var(--text-muted); margin-bottom: 32px; }

.results-breakdown {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(140px, 1fr));
  gap: 16px;
  margin: 24px 0;
  text-align: center;
}

.result-stat {
  background: #f8fafc;
  border-radius: 10px;
  padding: 16px;
}

.result-stat .num { font-size: 28px; font-weight: 800; }
.result-stat .lbl { font-size: 12px; color: var(--text-muted); text-transform: uppercase; }

/* ===== FLASHCARDS ===== */
.flashcard-container {
  perspective: 1000px;
  max-width: 600px;
  margin: 0 auto 24px;
}

.flashcard {
  width: 100%;
  height: 280px;
  position: relative;
  transform-style: preserve-3d;
  transition: transform 0.5s ease;
  cursor: pointer;
}

.flashcard.flipped { transform: rotateY(180deg); }

.flashcard-face {
  position: absolute;
  width: 100%;
  height: 100%;
  backface-visibility: hidden;
  border-radius: 16px;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 32px;
  text-align: center;
  box-shadow: var(--shadow-lg);
}

.flashcard-front {
  background: linear-gradient(135deg, var(--primary) 0%, #7c3aed 100%);
  color: white;
}

.flashcard-back {
  background: white;
  border: 2px solid var(--border);
  transform: rotateY(180deg);
  flex-direction: column;
  gap: 12px;
}

.flashcard-front h3 { font-size: 22px; font-weight: 800; }
.flashcard-front p { font-size: 14px; opacity: 0.8; margin-top: 8px; }
.flashcard-back-content { font-size: 15px; line-height: 1.7; color: var(--text); }
.flip-hint { font-size: 12px; color: var(--text-muted); }

.flashcard-nav {
  display: flex;
  justify-content: center;
  align-items: center;
  gap: 16px;
  margin-bottom: 16px;
}

/* ===== PRINCIPLES REFERENCE ===== */
.principle-card {
  background: white;
  border-radius: 12px;
  padding: 20px 24px;
  border: 1px solid var(--border);
  border-left: 4px solid var(--primary);
  margin-bottom: 12px;
}

.principle-num {
  font-size: 11px;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.5px;
  color: var(--primary);
  margin-bottom: 4px;
}

.principle-name { font-size: 16px; font-weight: 700; margin-bottom: 6px; }
.principle-desc { font-size: 14px; color: var(--text-muted); line-height: 1.6; }

/* ===== REVIEW TYPES TABLE ===== */
.review-table {
  width: 100%;
  border-collapse: collapse;
  font-size: 13px;
}

.review-table th {
  background: var(--primary);
  color: white;
  padding: 12px 16px;
  text-align: left;
  font-weight: 600;
}

.review-table td {
  padding: 12px 16px;
  border-bottom: 1px solid var(--border);
}

.review-table tr:nth-child(even) td { background: #f8fafc; }

/* ===== PROGRESS ===== */
.progress-section { margin-bottom: 32px; }

.progress-bar-wrapper {
  background: #e2e8f0;
  border-radius: 8px;
  height: 12px;
  overflow: hidden;
  margin-top: 6px;
}

.progress-bar-fill {
  height: 100%;
  border-radius: 8px;
  transition: width 0.4s ease;
}

.chapter-progress {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 4px;
  font-size: 14px;
}

/* ===== SEARCH ===== */
.search-box {
  width: 100%;
  padding: 14px 20px;
  border: 2px solid var(--border);
  border-radius: 10px;
  font-size: 16px;
  outline: none;
  background: white;
  margin-bottom: 20px;
  transition: border-color 0.2s;
}

.search-box:focus { border-color: var(--primary); }

.search-result {
  background: white;
  border-radius: 10px;
  padding: 16px 20px;
  border: 1px solid var(--border);
  margin-bottom: 10px;
  cursor: pointer;
  transition: all 0.2s;
}

.search-result:hover {
  border-color: var(--primary-light);
  box-shadow: var(--shadow);
}

.search-result h4 { font-size: 15px; font-weight: 600; margin-bottom: 6px; }
.search-result p { font-size: 13px; color: var(--text-muted); }

mark { background: #fef3c7; padding: 1px 2px; border-radius: 2px; }

/* ===== RESPONSIVE ===== */
@media (max-width: 640px) {
  header { flex-direction: column; gap: 12px; padding: 12px 16px; }
  nav { width: 100%; justify-content: center; flex-wrap: wrap; }
  .hero { padding: 28px 20px; }
  .hero h1 { font-size: 22px; }
  .hero-stats { gap: 12px; }
  .hero-stat { padding: 12px 16px; }
  main { padding: 16px 12px; }
  .quiz-card { padding: 20px 16px; }
  .question-text { font-size: 16px; }
}

/* ===== ANIMATIONS ===== */
@keyframes fadeIn {
  from { opacity: 0; transform: translateY(10px); }
  to { opacity: 1; transform: translateY(0); }
}

.page.active { animation: fadeIn 0.2s ease; }

/* ===== MULTI-SELECT HINT ===== */
.multi-hint {
  background: #eff6ff;
  border: 1px solid #bfdbfe;
  border-radius: 8px;
  padding: 10px 16px;
  font-size: 13px;
  color: #1e40af;
  margin-bottom: 16px;
  display: flex;
  align-items: center;
  gap: 8px;
}

/* ===== TOAST ===== */
.toast {
  position: fixed;
  bottom: 24px;
  right: 24px;
  background: #1e293b;
  color: white;
  padding: 12px 20px;
  border-radius: 10px;
  font-size: 14px;
  box-shadow: var(--shadow-lg);
  z-index: 999;
  animation: fadeIn 0.2s ease;
}

/* ===== FORMULA BOX ===== */
.formula-box {
  background: linear-gradient(135deg, #1e293b 0%, #334155 100%);
  color: #f8fafc;
  border-radius: 10px;
  padding: 20px 24px;
  font-family: 'Courier New', monospace;
  font-size: 18px;
  text-align: center;
  margin: 16px 0;
  letter-spacing: 0.5px;
}

.formula-box .formula-label {
  font-family: -apple-system, BlinkMacSystemFont, sans-serif;
  font-size: 12px;
  text-transform: uppercase;
  letter-spacing: 1px;
  opacity: 0.6;
  margin-bottom: 8px;
  display: block;
}

/* ===== SCROLL TO TOP ===== */
.scroll-top {
  position: fixed;
  bottom: 24px;
  left: 24px;
  background: var(--primary);
  color: white;
  border: none;
  border-radius: 50%;
  width: 44px;
  height: 44px;
  font-size: 18px;
  cursor: pointer;
  box-shadow: var(--shadow-md);
  display: none;
  align-items: center;
  justify-content: center;
  z-index: 50;
}

.scroll-top.visible { display: flex; }