/* ===== Reset & Base ===== */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }

:root {
  --primary: #1a73e8;
  --primary-dark: #1557b0;
  --success: #34a853;
  --danger: #ea4335;
  --warning: #fbbc04;
  --bg: #f0f4ff;
  --surface: #ffffff;
  --surface2: #f8f9fa;
  --text: #202124;
  --text2: #5f6368;
  --border: #dadce0;
  --radius: 16px;
  --shadow: 0 2px 12px rgba(0,0,0,0.1);
  --shadow-lg: 0 8px 32px rgba(0,0,0,0.15);
}

body {
  font-family: 'Segoe UI', system-ui, -apple-system, sans-serif;
  background: var(--bg);
  color: var(--text);
  min-height: 100vh;
  line-height: 1.5;
}

/* ===== Screens ===== */
.screen { display: none; min-height: 100vh; }
.screen.active { display: block; }

/* ===== HOME ===== */
.home-header {
  background: linear-gradient(135deg, #1a73e8 0%, #0d47a1 100%);
  color: white;
  text-align: center;
  padding: 48px 24px 40px;
}
.logo { font-size: 64px; margin-bottom: 12px; }
.home-header h1 { font-size: 2rem; font-weight: 700; letter-spacing: -0.5px; }
.home-header .subtitle { font-size: 1rem; opacity: 0.85; margin-top: 8px; }

.home-cards {
  display: flex;
  gap: 20px;
  padding: 28px 24px;
  max-width: 860px;
  margin: 0 auto;
  flex-wrap: wrap;
}

.card-mode {
  flex: 1;
  min-width: 280px;
  background: var(--surface);
  border-radius: var(--radius);
  padding: 28px 24px;
  cursor: pointer;
  box-shadow: var(--shadow);
  transition: transform 0.2s, box-shadow 0.2s;
  position: relative;
  overflow: hidden;
  border: 2px solid transparent;
}
.card-mode:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-lg);
}
.card-mode.detran { border-color: var(--primary); }
.card-mode.detran:hover { border-color: var(--primary-dark); }

.card-icon { font-size: 2.5rem; margin-bottom: 12px; }
.card-mode h2 { font-size: 1.3rem; font-weight: 700; margin-bottom: 8px; }
.card-mode p { color: var(--text2); font-size: 0.9rem; margin-bottom: 16px; }
.card-badge {
  display: inline-block;
  background: var(--primary);
  color: white;
  font-size: 0.7rem;
  font-weight: 700;
  letter-spacing: 1px;
  padding: 3px 10px;
  border-radius: 20px;
  margin-bottom: 12px;
}
.card-info { font-size: 0.82rem; color: var(--text2); display: flex; gap: 6px; }

.home-stats {
  max-width: 860px;
  margin: 0 auto;
  padding: 0 24px 32px;
  display: flex;
  gap: 12px;
  flex-wrap: wrap;
}
.stat-chip {
  background: var(--surface);
  border-radius: 24px;
  padding: 8px 16px;
  font-size: 0.85rem;
  color: var(--text2);
  box-shadow: var(--shadow);
  display: flex;
  align-items: center;
  gap: 6px;
}

/* ===== Top Bar ===== */
.top-bar {
  display: flex;
  align-items: center;
  gap: 16px;
  padding: 16px 24px;
  background: var(--surface);
  box-shadow: 0 1px 4px rgba(0,0,0,0.08);
  position: sticky;
  top: 0;
  z-index: 10;
}
.top-bar h2 { font-size: 1.1rem; font-weight: 600; }

/* ===== Categories ===== */
.categories-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(260px, 1fr));
  gap: 16px;
  padding: 24px;
  max-width: 900px;
  margin: 0 auto;
}

.category-card {
  background: var(--surface);
  border-radius: var(--radius);
  padding: 20px;
  cursor: pointer;
  box-shadow: var(--shadow);
  transition: transform 0.2s, box-shadow 0.2s;
  border-left: 5px solid transparent;
  display: flex;
  flex-direction: column;
  gap: 6px;
}
.category-card:hover { transform: translateY(-3px); box-shadow: var(--shadow-lg); }
.category-card .cat-icon { font-size: 2rem; }
.category-card h3 { font-size: 1rem; font-weight: 600; }
.category-card p { font-size: 0.82rem; color: var(--text2); }

/* ===== Exams List ===== */
.exams-list {
  display: flex;
  flex-direction: column;
  gap: 10px;
  padding: 20px 24px;
  max-width: 700px;
  margin: 0 auto;
}
.exam-item {
  background: var(--surface);
  border-radius: 12px;
  padding: 16px 20px;
  cursor: pointer;
  box-shadow: var(--shadow);
  display: flex;
  align-items: center;
  justify-content: space-between;
  transition: transform 0.15s, box-shadow 0.15s;
  border-left: 4px solid var(--primary);
}
.exam-item:hover { transform: translateX(4px); box-shadow: var(--shadow-lg); }
.exam-item .exam-name { font-weight: 600; font-size: 0.95rem; }
.exam-item .exam-meta { font-size: 0.8rem; color: var(--text2); margin-top: 2px; }
.exam-item .exam-arrow { color: var(--primary); font-size: 1.2rem; }

/* ===== Question Screen ===== */
.question-header {
  background: var(--surface);
  padding: 12px 20px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  box-shadow: 0 1px 4px rgba(0,0,0,0.08);
  position: sticky;
  top: 0;
  z-index: 10;
}
.progress-info { display: flex; flex-direction: column; align-items: center; gap: 2px; }
#q-counter { font-weight: 700; font-size: 0.9rem; }
.mode-label {
  font-size: 0.7rem;
  background: var(--primary);
  color: white;
  padding: 1px 8px;
  border-radius: 10px;
  font-weight: 600;
  letter-spacing: 0.5px;
}
.score-live {
  font-size: 0.82rem;
  font-weight: 600;
  background: var(--surface2);
  padding: 4px 12px;
  border-radius: 20px;
  color: var(--text2);
}

.progress-bar-wrap {
  height: 4px;
  background: var(--border);
}
.progress-bar {
  height: 100%;
  background: linear-gradient(90deg, var(--primary), #4285f4);
  transition: width 0.4s ease;
  width: 0%;
}

.question-body {
  max-width: 740px;
  margin: 0 auto;
  padding: 24px 20px 40px;
}

.question-image-wrap {
  margin-bottom: 20px;
  text-align: center;
}
.question-image-wrap img {
  display: block;
  margin: 0 auto;
  max-width: 280px;
  max-height: 200px;
  border-radius: 12px;
  border: 1px solid var(--border);
  object-fit: contain;
}
.image-placeholder {
  display: none;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  width: 200px;
  height: 140px;
  background: var(--surface2);
  border: 2px dashed var(--border);
  border-radius: 12px;
  margin: 0 auto;
  color: var(--text2);
  font-size: 0.85rem;
  gap: 4px;
}
.image-placeholder span { font-size: 2rem; }
.image-placeholder small { font-size: 0.75rem; font-family: monospace; }

.question-number-label {
  font-size: 0.8rem;
  font-weight: 700;
  color: var(--primary);
  text-transform: uppercase;
  letter-spacing: 0.5px;
  margin-bottom: 8px;
}
.question-text {
  font-size: 1.05rem;
  line-height: 1.65;
  color: var(--text);
  margin-bottom: 24px;
  font-weight: 500;
}

.alternatives { display: flex; flex-direction: column; gap: 10px; }

.alt-btn {
  width: 100%;
  text-align: left;
  background: var(--surface);
  border: 2px solid var(--border);
  border-radius: 12px;
  padding: 14px 18px;
  cursor: pointer;
  font-size: 0.95rem;
  line-height: 1.5;
  display: flex;
  align-items: flex-start;
  gap: 12px;
  transition: border-color 0.15s, background 0.15s, transform 0.1s;
  color: var(--text);
}
.alt-btn:hover:not(:disabled) {
  border-color: var(--primary);
  background: #e8f0fe;
  transform: translateX(2px);
}
.alt-btn:disabled { cursor: default; }

.alt-letter {
  flex-shrink: 0;
  width: 28px;
  height: 28px;
  border-radius: 50%;
  background: var(--surface2);
  border: 2px solid var(--border);
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 700;
  font-size: 0.85rem;
  color: var(--text2);
  transition: background 0.15s, border-color 0.15s;
}
.alt-text { padding-top: 2px; }

/* Alternative states */
.alt-btn.selected { border-color: var(--primary); background: #e8f0fe; }
.alt-btn.selected .alt-letter { background: var(--primary); border-color: var(--primary); color: white; }

.alt-btn.correct { border-color: var(--success); background: #e6f4ea; }
.alt-btn.correct .alt-letter { background: var(--success); border-color: var(--success); color: white; }

.alt-btn.wrong { border-color: var(--danger); background: #fce8e6; }
.alt-btn.wrong .alt-letter { background: var(--danger); border-color: var(--danger); color: white; }

.alt-btn.highlight-correct { border-color: var(--success); background: #e6f4ea; }
.alt-btn.highlight-correct .alt-letter { background: var(--success); border-color: var(--success); color: white; }

/* Feedback */
.feedback-box {
  margin-top: 16px;
  padding: 16px 20px;
  border-radius: 12px;
  display: flex;
  gap: 14px;
  align-items: flex-start;
}
.feedback-box.correct-fb { background: #e6f4ea; border: 1px solid #a8d5b5; }
.feedback-box.wrong-fb { background: #fce8e6; border: 1px solid #f5b8b4; }
.feedback-icon { font-size: 1.6rem; flex-shrink: 0; }
.feedback-text p { font-weight: 600; margin-bottom: 4px; }
.feedback-correct { font-size: 0.88rem; color: var(--text2); font-weight: 400 !important; }

.question-actions { text-align: right; margin-top: 20px; }

/* ===== Buttons ===== */
.btn-back {
  background: none;
  border: none;
  color: var(--primary);
  font-size: 0.9rem;
  cursor: pointer;
  padding: 4px 8px;
  font-weight: 600;
  flex-shrink: 0;
}
.btn-action {
  border: none;
  border-radius: 24px;
  padding: 12px 28px;
  font-size: 1rem;
  font-weight: 600;
  cursor: pointer;
  transition: transform 0.15s, opacity 0.15s;
}
.btn-action:hover { transform: scale(1.03); }
.btn-next { background: var(--primary); color: white; }

.btn-primary {
  background: var(--primary);
  color: white;
  border: none;
  border-radius: 24px;
  padding: 13px 28px;
  font-size: 1rem;
  font-weight: 600;
  cursor: pointer;
  transition: background 0.15s;
}
.btn-primary:hover { background: var(--primary-dark); }

.btn-secondary {
  background: var(--surface);
  color: var(--text);
  border: 2px solid var(--border);
  border-radius: 24px;
  padding: 11px 24px;
  font-size: 1rem;
  font-weight: 600;
  cursor: pointer;
  transition: background 0.15s;
}
.btn-secondary:hover { background: var(--surface2); }

.btn-danger {
  background: var(--danger);
  color: white;
  border: none;
  border-radius: 24px;
  padding: 11px 24px;
  font-size: 1rem;
  font-weight: 600;
  cursor: pointer;
}

/* ===== Result Screen ===== */
.result-container {
  max-width: 600px;
  margin: 0 auto;
  padding: 32px 24px;
  text-align: center;
}
.result-icon { font-size: 4rem; margin-bottom: 12px; }
.result-container h2 { font-size: 1.8rem; font-weight: 700; margin-bottom: 8px; }
.result-container > p { color: var(--text2); margin-bottom: 28px; }

.result-score-circle {
  position: relative;
  width: 160px;
  height: 160px;
  margin: 0 auto 28px;
}
.result-score-circle svg {
  transform: rotate(-90deg);
  width: 100%;
  height: 100%;
}
.circle-bg { fill: none; stroke: var(--border); stroke-width: 8; }
.circle-fg {
  fill: none;
  stroke: var(--success);
  stroke-width: 8;
  stroke-linecap: round;
  stroke-dasharray: 339.3;
  stroke-dashoffset: 339.3;
  transition: stroke-dashoffset 1s ease;
}
.circle-fg.fail { stroke: var(--danger); }

.score-text {
  position: absolute;
  inset: 0;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 2px;
}
.score-text span { font-size: 2rem; font-weight: 700; }
.score-text small { font-size: 0.75rem; color: var(--text2); }

.result-stats {
  display: flex;
  gap: 16px;
  justify-content: center;
  margin-bottom: 24px;
}
.stat-item {
  background: var(--surface);
  border-radius: 12px;
  padding: 14px 20px;
  box-shadow: var(--shadow);
  min-width: 90px;
}
.stat-item span { display: block; font-size: 1.8rem; font-weight: 700; }
.stat-item label { font-size: 0.78rem; color: var(--text2); }
.stat-item.correct span { color: var(--success); }
.stat-item.wrong span { color: var(--danger); }

.result-breakdown {
  background: var(--surface);
  border-radius: 12px;
  padding: 16px;
  box-shadow: var(--shadow);
  margin-bottom: 24px;
  text-align: left;
}
.breakdown-title { font-weight: 700; margin-bottom: 12px; font-size: 0.9rem; }
.breakdown-row {
  display: flex;
  align-items: center;
  gap: 10px;
  margin-bottom: 8px;
  font-size: 0.85rem;
}
.breakdown-label { flex: 1; color: var(--text2); }
.breakdown-bar-wrap { flex: 2; height: 8px; background: var(--border); border-radius: 4px; overflow: hidden; }
.breakdown-bar { height: 100%; border-radius: 4px; background: var(--primary); transition: width 1s ease; }
.breakdown-count { font-weight: 700; font-size: 0.8rem; min-width: 40px; text-align: right; }

.result-actions {
  display: flex;
  gap: 12px;
  justify-content: center;
  flex-wrap: wrap;
}

/* ===== Review Screen ===== */
.review-list {
  max-width: 740px;
  margin: 0 auto;
  padding: 20px 24px 40px;
  display: flex;
  flex-direction: column;
  gap: 16px;
}
.review-item {
  background: var(--surface);
  border-radius: 12px;
  padding: 18px;
  box-shadow: var(--shadow);
  border-left: 4px solid var(--border);
}
.review-item.correct-item { border-left-color: var(--success); }
.review-item.wrong-item { border-left-color: var(--danger); }
.review-q-header {
  display: flex;
  gap: 10px;
  align-items: flex-start;
  margin-bottom: 12px;
}
.review-num {
  flex-shrink: 0;
  width: 28px;
  height: 28px;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 700;
  font-size: 0.82rem;
  color: white;
}
.correct-item .review-num { background: var(--success); }
.wrong-item .review-num { background: var(--danger); }
.review-q-text { font-size: 0.9rem; font-weight: 500; }
.review-answers { display: flex; flex-direction: column; gap: 6px; font-size: 0.85rem; }
.review-answer-row { display: flex; gap: 8px; }
.review-answer-row .lbl { color: var(--text2); }
.review-answer-row .val { font-weight: 600; }
.review-answer-row .val.ok { color: var(--success); }
.review-answer-row .val.err { color: var(--danger); }

/* ===== Modal ===== */
.modal-overlay {
  position: fixed;
  inset: 0;
  background: rgba(0,0,0,0.5);
  display: flex;
  align-items: center;
  justify-content: center;
  z-index: 100;
}
.modal-box {
  background: var(--surface);
  border-radius: var(--radius);
  padding: 28px;
  max-width: 340px;
  width: 90%;
  box-shadow: var(--shadow-lg);
}
.modal-box h3 { font-size: 1.2rem; margin-bottom: 8px; }
.modal-box p { color: var(--text2); margin-bottom: 20px; }
.modal-actions { display: flex; gap: 12px; justify-content: flex-end; }

/* ===== Responsive ===== */
@media (max-width: 540px) {
  .home-header h1 { font-size: 1.5rem; }
  .card-mode { min-width: 100%; }
  .question-text { font-size: 0.95rem; }
  .result-container { padding: 20px 16px; }
}