/* ========= RESET & THEME ========= */
* {
  box-sizing: border-box;
}

:root {
  --bg: #eef2ff;
  --card-bg: #ffffff;
  --primary: #2563eb;
  --primary-soft: #dbeafe;
  --danger: #dc2626;
  --text: #0f172a;
  --muted: #6b7280;
  --border: #e5e7eb;
  --radius: 18px;
  --shadow: 0 16px 50px rgba(15, 23, 42, 0.18);
}

body {
  margin: 0;
  font-family: "Segoe UI", system-ui, -apple-system, BlinkMacSystemFont,
    sans-serif;
  background: radial-gradient(circle at 20% 20%, #e0f2fe, #eef2ff 45%, #f8fafc);
  color: var(--text);
  min-height: 100vh;
}

/* ========= APP WRAPPER ========= */

.app {
  max-width: 1280px;
  margin: 0 auto;
  padding: 12px 16px 18px;
}

/* ========= HEADER ========= */

.app-header {
  padding: 20px 0 10px;
  margin-bottom: 14px;
  display: flex;
  flex-direction: column;
  gap: 8px;
}

.title-wrap {
  display: flex;
  align-items: center;
  gap: 10px;
}

.logo-mark {
  width: 48px;
  height: 48px;
  border-radius: 14px;
  background: linear-gradient(135deg, #2563eb, #60a5fa);
  color: #e0ecff;
  display: grid;
  place-items: center;
  box-shadow: 0 12px 26px rgba(37, 99, 235, 0.28);
}

.app-header h1 {
  margin: 4px 0;
  font-size: 1.6rem;
  letter-spacing: 0.2px;
}

.subtitle {
  margin: 0;
  color: var(--muted);
  font-size: 0.9rem;
}

.pill {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  font-size: 0.82rem;
  padding: 7px 12px;
  border-radius: 999px;
  border: 1px solid var(--border);
  color: #0f172a;
}

.pill-soft {
  background: #eef2ff;
  color: #1d4ed8;
  border-color: #dbeafe;
}

/* ========= CARD CHUNG ========= */

.control-panel,
.quiz-area,
.result-area {
  background: var(--card-bg);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
}

/* ========= HOME: CHON DE & MODE ========= */

.control-panel {
  padding: 12px;
  margin-bottom: 10px;
  display: grid;
  grid-template-columns: 1fr;
  gap: 10px;
}

.control-group {
  display: flex;
  flex-direction: column;
  gap: 6px;
  font-size: 0.9rem;
}

.control-group label {
  font-size: 0.9rem;
  color: var(--text);
}

.label-block {
  font-weight: 600;
  font-size: 0.9rem;
}

.mode-option {
  display: flex;
  align-items: center;
  gap: 6px;
  font-size: 0.85rem;
}

.settings-block {
  border: 1px dashed var(--border);
  border-radius: 12px;
  padding: 8px 10px;
  background: #f8fafc;
}

.settings-row {
  display: flex;
  gap: 12px;
  flex-wrap: wrap;
}

.option-icon {
  font-size: 1rem;
}

.control-group select {
  width: 100%;
  padding: 10px 12px;
  border-radius: 12px;
  border: 1px solid var(--border);
  font-size: 0.92rem;
  background: #f9fafb;
}

.select-wrap {
  position: relative;
  display: flex;
  align-items: center;
  gap: 10px;
  background: #f9fafb;
  border: 1px solid var(--border);
  border-radius: 14px;
  padding: 6px 10px 6px 12px;
  box-shadow: inset 0 1px 0 rgba(255, 255, 255, 0.6);
}

.select-wrap select {
  background: transparent;
  border: none;
  padding: 10px 8px;
  font-size: 1rem;
  flex: 1;
  outline: none;
}

.select-prefix {
  width: 32px;
  height: 32px;
  border-radius: 10px;
  background: linear-gradient(135deg, #2563eb, #60a5fa);
  color: white;
  display: grid;
  place-items: center;
  font-size: 1.1rem;
  box-shadow: 0 8px 16px rgba(37, 99, 235, 0.25);
}

.select-hint {
  font-size: 0.75rem;
  color: var(--muted);
  white-space: nowrap;
}

.btn {
  border: 1px solid transparent;
  border-radius: 999px;
  padding: 11px 18px;
  font-size: 0.92rem;
  cursor: pointer;
  background: #e5e7eb;
  color: var(--text);
  transition: transform 0.1s ease, box-shadow 0.16s ease, background 0.1s ease,
    border-color 0.1s ease;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
}

.btn.primary {
  background: linear-gradient(135deg, #2563eb, #1d4ed8);
  color: white;
  box-shadow: 0 10px 30px rgba(37, 99, 235, 0.28);
}

.btn.secondary {
  background: #e0f2fe;
  color: #1d4ed8;
}

.btn.danger {
  background: #fee2e2;
  color: #b91c1c;
}

.btn.ghost {
  background: transparent;
  color: var(--muted);
  border-color: var(--border);
}

.btn.wide {
  width: 100%;
}

.btn:hover {
  transform: translateY(-1px);
  box-shadow: 0 8px 18px rgba(15, 23, 42, 0.12);
}

.btn:active {
  transform: translateY(0);
  box-shadow: none;
}

#btn-start:hover {
  background: linear-gradient(135deg, #2f6ff0, #2556c9);
  box-shadow: 0 12px 28px rgba(37, 99, 235, 0.35);
}

.btn-icon {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 1.1em;
}

/* ========= QUIZ: KHUNG CONG VIEC ========= */

.quiz-area {
  padding: 12px;
  margin-bottom: 12px;

  /* khung co dinh gan full man hinh, scroll ben trong */
  max-height: calc(100vh - 90px);
  display: flex;
  flex-direction: column;
  gap: 8px;
}

.hidden {
  display: none !important;
}

.quiz-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 6px;
  padding: 4px 2px 0;
}

.quiz-actions {
  display: flex;
  align-items: center;
  gap: 8px;
}

.quiz-info {
  display: flex;
  flex-direction: column;
  gap: 2px;
  font-size: 0.85rem;
}

#exam-title {
  font-weight: 600;
}

#question-progress {
  font-size: 0.8rem;
  color: var(--muted);
}

.mode-badge {
  display: inline-block;
  margin-top: 2px;
  padding: 2px 8px;
  border-radius: 999px;
  font-size: 0.7rem;
  background: #fef3c7;
  color: #92400e;
}

.mode-badge.practice {
  background: #dcfce7;
  color: #166534;
}

.quiz-timer {
  font-size: 0.8rem;
  color: var(--muted);
  background: #e0ecff;
  padding: 4px 10px;
  border-radius: 999px;
  display: inline-flex;
  align-items: center;
  gap: 6px;
}

.timer-icon {
  width: 16px;
  height: 16px;
}

/* noi dung ben trong card (cau hoi + so do) scroll */
.quiz-layout {
  margin-top: 6px;
  flex: 1;
  overflow-y: auto;
  display: flex;
  flex-direction: column;
  gap: 8px;
  max-width: 1160px;
  margin-left: auto;
  margin-right: auto;
}

/* ========= COT CAU HOI ========= */

.question-column {
  display: flex;
  flex-direction: column;
  gap: 8px;
}

.question-card {
  border-radius: 18px;
  border: 1px solid var(--border);
  padding: 14px;
  background: linear-gradient(160deg, #ffffff 0%, #f8fbff 80%);
  box-shadow: 0 12px 32px rgba(15, 23, 42, 0.08);
}

.question-text {
  font-weight: 600;
  margin-bottom: 8px;
  font-size: 0.95rem;
}

.options-list {
  display: flex;
  flex-direction: column;
  gap: 6px;
}

.option-btn {
  width: 100%;
  text-align: left;
  border-radius: 12px;
  border: 1px solid var(--border);
  padding: 8px 10px;
  background: white;
  display: flex;
  gap: 6px;
  align-items: flex-start;
  cursor: pointer;
  font-size: 0.9rem;
  transition: border-color 0.12s ease, background 0.12s ease,
    box-shadow 0.12s ease;
}

.option-prefix {
  font-weight: 600;
  color: var(--muted);
  min-width: 22px;
}

.option-text {
  flex: 1;
}

.option-btn.selected {
  border-color: var(--primary);
  background: var(--primary-soft);
  box-shadow: 0 6px 18px rgba(37, 99, 235, 0.15);
}

.option-btn.correct {
  border-color: #16a34a;
  background: #dcfce7;
}

.option-btn.incorrect {
  border-color: #dc2626;
  background: #fee2e2;
}

/* ========= NAVIGATION ========= */

.nav-buttons {
  display: flex;
  gap: 6px;
  flex-wrap: nowrap;
  margin-top: 2px;
}

.nav-buttons .btn {
  flex: 1;
  min-width: 0;
  font-size: 0.88rem;
  padding: 9px 10px;
}

/* ========= SIDEBAR ========= */

.sidebar {
  border-top: 1px solid var(--border);
  padding-top: 6px;
}

.sidebar h3 {
  margin: 0 0 4px;
  font-size: 0.9rem;
}

.question-map-legend {
  font-size: 0.75rem;
  color: var(--muted);
  display: flex;
  align-items: center;
  gap: 6px;
  flex-wrap: wrap;
  margin: 0 0 4px;
}

.dot {
  width: 9px;
  height: 9px;
  border-radius: 999px;
  display: inline-block;
}

.dot-current {
  background: #2563eb;
}

.dot-answered {
  background: #16a34a;
}

.dot-empty {
  background: #d1d5db;
}

.question-map {
  margin-top: 2px;
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(28px, 1fr));
  gap: 4px;
}

.qmap-btn {
  border: none;
  border-radius: 8px;
  padding: 4px 0;
  font-size: 0.75rem;
  cursor: pointer;
  background: #e5e7eb;
  color: #111827;
}

.qmap-btn.current {
  background: #2563eb;
  color: #fff;
}

.qmap-btn.answered {
  background: #22c55e;
  color: #fff;
}

.qmap-btn.empty {
  background: #e5e7eb;
  color: #4b5563;
}

.qmap-btn:hover {
  opacity: 0.9;
}

/* ========= KET QUA ========= */

.result-area {
  padding: 14px;
  margin-bottom: 12px;
}

.result-area h2 {
  margin-top: 0;
  font-size: 1rem;
}

#result-summary {
  font-weight: 500;
  margin-bottom: 8px;
  font-size: 0.9rem;
}

.result-detail {
  font-size: 0.8rem;
  color: var(--muted);
  white-space: pre-wrap;
  background: #f9fafb;
  padding: 8px;
  border-radius: 12px;
  border: 1px solid var(--border);
  max-height: 260px;
  overflow: auto;
}

.result-actions {
  margin-top: 8px;
  display: flex;
  gap: 6px;
  flex-wrap: wrap;
}

.result-actions .btn {
  flex: 1;
  min-width: 0;
  font-size: 0.85rem;
}

/* ========= FOOTER ========= */

.app-footer {
  text-align: center;
  font-size: 0.78rem;
  color: var(--muted);
  margin-top: 6px;
}

/* ========= RESPONSIVE ========= */

@media (min-width: 720px) {
  .control-panel {
    grid-template-columns: repeat(2, minmax(0, 1fr));
    align-items: end;
  }

  .settings-block {
    flex-direction: row;
    grid-column: span 2;
  }
}

@media (min-width: 980px) {
  .app {
    padding: 14px 20px 22px;
  }

  .app-header h1 {
    font-size: 1.7rem;
  }

  .control-panel {
    grid-template-columns: repeat(3, minmax(0, 1fr));
    gap: 12px;
  }

  .settings-block {
    grid-column: span 3;
  }

  .quiz-layout {
    flex-direction: row;
    gap: 10px;
  }

  .question-column {
    flex: 2.6;
  }

  .sidebar {
    flex: 1.1;
    border-top: none;
    border-left: 1px solid var(--border);
    padding-top: 0;
    padding-left: 10px;
  }
}