/* ============================================================
   QUIZMASTER PRO — DESIGN SYSTEM & STYLESHEET
   ============================================================ */

/* ===== RESET & ROOT VARIABLES ===== */
*, *::before, *::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

:root {
  --bg-dark: #090d16;
  --bg-card: #121829;
  --bg-card-hover: #182036;
  --bg-card-selected: rgba(108, 92, 231, 0.12);
  --border-color: rgba(255, 255, 255, 0.08);
  --border-focus: rgba(108, 92, 231, 0.5);

  --primary: #6c5ce7;
  --primary-light: #a29bfe;
  --primary-dark: #4834d4;
  --primary-glow: rgba(108, 92, 231, 0.35);

  --accent-cyan: #00cec9;
  --accent-pink: #fd79a8;

  --success: #00b894;
  --success-glow: rgba(0, 184, 148, 0.25);
  --danger: #ff7675;
  --danger-glow: rgba(255, 118, 117, 0.25);
  --warning: #fdcb6e;

  --text-main: #f1f3f9;
  --text-muted: #94a3b8;
  --text-dim: #64748b;

  --radius-lg: 20px;
  --radius-md: 12px;
  --radius-sm: 8px;
  --radius-pill: 50px;

  --shadow-main: 0 12px 36px rgba(0, 0, 0, 0.5);
  --shadow-glow: 0 0 25px var(--primary-glow);
  --transition-fast: 0.2s cubic-bezier(0.4, 0, 0.2, 1);
  --transition-normal: 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

html {
  font-size: 16px;
  scroll-behavior: smooth;
}

body {
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
  background-color: var(--bg-dark);
  color: var(--text-main);
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  background-image: 
    radial-gradient(circle at 15% 15%, rgba(108, 92, 231, 0.15) 0%, transparent 45%),
    radial-gradient(circle at 85% 85%, rgba(0, 206, 201, 0.12) 0%, transparent 45%),
    radial-gradient(circle at 50% 50%, rgba(15, 23, 42, 0.8) 0%, var(--bg-dark) 100%);
  background-attachment: fixed;
  overflow-x: hidden;
}

/* Custom Scrollbar */
::-webkit-scrollbar {
  width: 8px;
}
::-webkit-scrollbar-track {
  background: var(--bg-dark);
}
::-webkit-scrollbar-thumb {
  background: #2a344d;
  border-radius: 4px;
}
::-webkit-scrollbar-thumb:hover {
  background: var(--primary);
}

/* ===== LAYOUT & APP CONTAINER ===== */
.app-container {
  width: 100%;
  max-width: 900px;
  min-height: 100vh;
  padding: 24px 16px;
  display: flex;
  flex-direction: column;
  justify-content: center;
}

/* App Header Controls */
.top-nav {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 20px;
  padding: 0 8px;
}

.brand-logo {
  display: flex;
  align-items: center;
  gap: 10px;
  font-size: 1.2rem;
  font-weight: 800;
  background: linear-gradient(135deg, var(--primary-light), var(--accent-cyan));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  letter-spacing: -0.5px;
}

.audio-toggle-btn {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  color: var(--text-muted);
  padding: 8px 16px;
  border-radius: var(--radius-pill);
  font-size: 0.85rem;
  font-weight: 600;
  cursor: pointer;
  display: flex;
  align-items: center;
  gap: 8px;
  transition: var(--transition-normal);
}

.audio-toggle-btn:hover {
  background: var(--bg-card-hover);
  color: var(--text-main);
  border-color: var(--border-focus);
}

/* Screens Wrapper */
.screen {
  display: none;
  width: 100%;
  animation: fadeIn 0.4s ease;
}

.screen.active {
  display: block;
}

@keyframes fadeIn {
  from { opacity: 0; transform: translateY(16px); }
  to { opacity: 1; transform: translateY(0); }
}

@keyframes pulseWarn {
  0%, 100% { transform: scale(1); opacity: 1; }
  50% { transform: scale(1.08); opacity: 0.8; color: var(--danger); }
}

@keyframes confettiFall {
  0% { transform: translateY(0) rotate(0deg); opacity: 1; }
  100% { transform: translateY(800px) rotate(720deg); opacity: 0; }
}

/* ===== CARDS & PANELS ===== */
.main-card {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  padding: 36px 30px;
  box-shadow: var(--shadow-main);
  backdrop-filter: blur(16px);
  position: relative;
  overflow: hidden;
}

.main-card::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 3px;
  background: linear-gradient(90deg, var(--primary), var(--accent-cyan), var(--primary-light));
}

/* ===== CONFIG SCREEN ===== */
.config-header {
  text-align: center;
  margin-bottom: 24px;
}

.config-header h1 {
  font-size: 2.2rem;
  font-weight: 800;
  margin-bottom: 8px;
  background: linear-gradient(135deg, #ffffff 30%, var(--primary-light));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.config-header p {
  color: var(--text-muted);
  font-size: 0.95rem;
}

/* Mode Selection Pills */
.mode-container {
  display: flex;
  justify-content: center;
  gap: 12px;
  margin-bottom: 20px;
}

.mode-btn {
  padding: 10px 24px;
  border-radius: var(--radius-pill);
  border: 1.5px solid var(--border-color);
  background: transparent;
  color: var(--text-muted);
  font-size: 0.9rem;
  font-weight: 600;
  cursor: pointer;
  transition: var(--transition-normal);
}

.mode-btn.active {
  background: linear-gradient(135deg, var(--primary), var(--primary-dark));
  border-color: var(--primary);
  color: #fff;
  box-shadow: var(--shadow-glow);
}

.mode-btn:hover:not(.active) {
  border-color: var(--text-muted);
  color: var(--text-main);
}

/* Search Bar & Category Controls */
.search-filter-box {
  display: flex;
  gap: 12px;
  margin-bottom: 16px;
}

.search-input-wrapper {
  position: relative;
  flex: 1;
}

.search-input {
  width: 100%;
  padding: 12px 16px 12px 42px;
  background: #0d121f;
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  color: var(--text-main);
  font-size: 0.9rem;
  outline: none;
  transition: var(--transition-fast);
}

.search-input:focus {
  border-color: var(--primary);
  box-shadow: 0 0 0 3px rgba(108, 92, 231, 0.2);
}

.search-icon {
  position: absolute;
  left: 14px;
  top: 50%;
  transform: translateY(-50%);
  color: var(--text-dim);
  font-size: 1rem;
}

/* Category Grid */
.category-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(210px, 1fr));
  gap: 10px;
  max-height: 400px;
  overflow-y: auto;
  padding: 6px;
  margin-bottom: 24px;
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  background: rgba(10, 14, 26, 0.5);
}

.cat-item {
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 12px 14px;
  background: var(--bg-card);
  border-radius: var(--radius-sm);
  border: 1.5px solid transparent;
  cursor: pointer;
  transition: var(--transition-fast);
  user-select: none;
}

.cat-item:hover {
  border-color: rgba(255, 255, 255, 0.15);
  background: var(--bg-card-hover);
}

.cat-item.selected {
  border-color: var(--primary);
  background: var(--bg-card-selected);
}

.cat-item .checkbox {
  width: 22px;
  height: 22px;
  border-radius: 6px;
  border: 2px solid var(--text-dim);
  display: flex;
  align-items: center;
  justify-content: center;
  flex-shrink: 0;
  font-size: 12px;
  color: transparent;
  transition: var(--transition-fast);
}

.cat-item.selected .checkbox {
  background: var(--primary);
  border-color: var(--primary);
  color: #fff;
}

.cat-item .cat-name {
  font-size: 0.85rem;
  font-weight: 500;
  line-height: 1.3;
}

.cat-item .cat-count {
  font-size: 0.72rem;
  color: var(--text-dim);
  margin-left: auto;
  white-space: nowrap;
  background: rgba(255, 255, 255, 0.05);
  padding: 2px 6px;
  border-radius: 4px;
}

/* Action Buttons */
.config-actions {
  display: flex;
  gap: 12px;
  justify-content: center;
  flex-wrap: wrap;
}

.btn {
  padding: 14px 32px;
  border-radius: var(--radius-pill);
  border: none;
  font-size: 0.95rem;
  font-weight: 700;
  cursor: pointer;
  transition: var(--transition-normal);
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
}

.btn-primary {
  background: linear-gradient(135deg, var(--primary), var(--primary-dark));
  color: #fff;
  box-shadow: 0 6px 20px rgba(108, 92, 231, 0.35);
}

.btn-primary:hover:not(:disabled) {
  transform: translateY(-2px);
  box-shadow: 0 10px 28px rgba(108, 92, 231, 0.5);
}

.btn-primary:disabled {
  opacity: 0.4;
  cursor: not-allowed;
  transform: none;
  box-shadow: none;
}

.btn-secondary {
  background: rgba(255, 255, 255, 0.06);
  color: var(--text-main);
  border: 1px solid var(--border-color);
}

.btn-secondary:hover {
  background: rgba(255, 255, 255, 0.12);
  border-color: var(--text-muted);
}

.btn-sm {
  padding: 10px 20px;
  font-size: 0.85rem;
}

.info-counter-text {
  text-align: center;
  color: var(--text-muted);
  font-size: 0.82rem;
  margin-top: 14px;
}

.info-counter-text strong {
  color: var(--primary-light);
}

/* ===== QUIZ GAMEPLAY SCREEN ===== */
.quiz-top-bar {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding-bottom: 16px;
  margin-bottom: 20px;
  border-bottom: 1px solid var(--border-color);
  gap: 16px;
}

.quiz-progress {
  display: flex;
  align-items: center;
  gap: 14px;
  font-size: 0.9rem;
  font-weight: 600;
  color: var(--text-muted);
  flex: 1;
}

.quiz-progress .bar {
  flex: 1;
  height: 8px;
  background: #0d121f;
  border-radius: 4px;
  overflow: hidden;
  border: 1px solid var(--border-color);
}

.quiz-progress .bar-fill {
  height: 100%;
  background: linear-gradient(90deg, var(--primary), var(--accent-cyan));
  border-radius: 4px;
  transition: width 0.4s ease;
}

.quiz-timer {
  display: flex;
  align-items: center;
  gap: 8px;
  font-size: 1rem;
  font-weight: 700;
  color: var(--text-main);
  background: rgba(255, 255, 255, 0.05);
  padding: 6px 14px;
  border-radius: var(--radius-pill);
  border: 1px solid var(--border-color);
  font-variant-numeric: tabular-nums;
}

.quiz-category-badge {
  display: inline-block;
  padding: 6px 16px;
  border-radius: var(--radius-pill);
  background: rgba(108, 92, 231, 0.18);
  color: var(--primary-light);
  font-size: 0.8rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.5px;
  margin-bottom: 16px;
  border: 1px solid rgba(108, 92, 231, 0.3);
}

.quiz-question {
  font-size: 1.35rem;
  font-weight: 700;
  line-height: 1.5;
  margin-bottom: 26px;
  color: #ffffff;
}

.quiz-options {
  display: flex;
  flex-direction: column;
  gap: 14px;
}

.quiz-option {
  display: flex;
  align-items: center;
  gap: 16px;
  padding: 16px 20px;
  background: #0d121f;
  border-radius: var(--radius-md);
  border: 2px solid var(--border-color);
  cursor: pointer;
  transition: var(--transition-fast);
  user-select: none;
  position: relative;
}

.quiz-option:hover:not(.disabled) {
  border-color: var(--primary-light);
  background: var(--bg-card-hover);
  transform: translateX(4px);
}

.quiz-option .opt-letter {
  width: 36px;
  height: 36px;
  border-radius: 10px;
  background: rgba(255, 255, 255, 0.06);
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 800;
  font-size: 0.9rem;
  color: var(--text-muted);
  flex-shrink: 0;
  transition: var(--transition-fast);
}

.quiz-option .opt-text {
  font-size: 0.98rem;
  line-height: 1.4;
  color: var(--text-main);
  flex: 1;
}

/* Quiz Option Feedback States */
.quiz-option.selected {
  border-color: var(--primary);
  background: var(--bg-card-selected);
}

.quiz-option.selected .opt-letter {
  background: var(--primary);
  color: #fff;
}

.quiz-option.correct {
  border-color: var(--success);
  background: rgba(0, 184, 148, 0.14);
}

.quiz-option.correct .opt-letter {
  background: var(--success);
  color: #fff;
}

.quiz-option.wrong {
  border-color: var(--danger);
  background: rgba(255, 118, 117, 0.14);
}

.quiz-option.wrong .opt-letter {
  background: var(--danger);
  color: #fff;
}

.quiz-option.disabled {
  cursor: default;
  opacity: 0.9;
}

.quiz-option .opt-feedback {
  position: absolute;
  right: 18px;
  font-size: 1.2rem;
  font-weight: 800;
  opacity: 0;
  transition: var(--transition-fast);
}

.quiz-option.correct .opt-feedback {
  opacity: 1;
  color: var(--success);
}

.quiz-option.wrong .opt-feedback {
  opacity: 1;
  color: var(--danger);
}

.quiz-next-btn {
  display: none;
  margin-top: 24px;
  text-align: center;
}

.quiz-next-btn.show {
  display: block;
  animation: fadeIn 0.3s ease;
}

.quiz-question-num {
  text-align: center;
  color: var(--text-dim);
  font-size: 0.85rem;
  margin-top: 18px;
}

/* ===== RESULTS SCREEN ===== */
.results-header {
  text-align: center;
  margin-bottom: 28px;
}

.results-header .big-score {
  font-size: 4.2rem;
  font-weight: 900;
  background: linear-gradient(135deg, var(--primary-light), var(--accent-cyan));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  line-height: 1;
  margin-bottom: 6px;
}

.results-header .score-label {
  color: var(--text-muted);
  font-size: 1rem;
}

.results-header .score-grade {
  display: inline-block;
  margin-top: 10px;
  padding: 8px 24px;
  border-radius: var(--radius-pill);
  font-size: 1.15rem;
  font-weight: 800;
}

.grade-excellent {
  background: rgba(0, 184, 148, 0.2);
  color: var(--success);
  border: 1px solid var(--success);
}

.grade-good {
  background: rgba(108, 92, 231, 0.2);
  color: var(--primary-light);
  border: 1px solid var(--primary);
}

.grade-average {
  background: rgba(253, 203, 110, 0.2);
  color: var(--warning);
  border: 1px solid var(--warning);
}

.grade-poor {
  background: rgba(255, 118, 117, 0.2);
  color: var(--danger);
  border: 1px solid var(--danger);
}

/* Stats Cards Grid */
.stats-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(160px, 1fr));
  gap: 14px;
  margin-bottom: 24px;
}

.stat-card {
  background: #0d121f;
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  padding: 18px 14px;
  text-align: center;
}

.stat-card .stat-value {
  font-size: 1.7rem;
  font-weight: 800;
  color: var(--text-main);
}

.stat-card .stat-label {
  font-size: 0.78rem;
  color: var(--text-dim);
  margin-top: 4px;
  text-transform: uppercase;
  letter-spacing: 0.5px;
  font-weight: 600;
}

.stat-card.highlight {
  background: var(--bg-card-selected);
  border-color: var(--primary);
}

/* Results Breakdown */
.results-detail {
  margin-bottom: 24px;
}

.results-detail h3 {
  font-size: 1.05rem;
  color: var(--text-muted);
  margin-bottom: 12px;
  font-weight: 700;
}

.results-breakdown {
  display: flex;
  flex-direction: column;
  gap: 8px;
  max-height: 220px;
  overflow-y: auto;
  padding-right: 4px;
}

.breakdown-item {
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 10px 14px;
  background: #0d121f;
  border: 1px solid var(--border-color);
  border-radius: var(--radius-sm);
  font-size: 0.88rem;
}

.breakdown-item .bd-status {
  width: 10px;
  height: 10px;
  border-radius: 50%;
  flex-shrink: 0;
}

.bd-status.correct {
  background: var(--success);
  box-shadow: 0 0 8px var(--success);
}

.bd-status.wrong {
  background: var(--danger);
  box-shadow: 0 0 8px var(--danger);
}

.breakdown-item .bd-cat {
  color: var(--text-dim);
  font-size: 0.8rem;
  margin-left: auto;
}

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

/* ===== CONFETTI PARTICLES ===== */
.confetti-piece {
  position: fixed;
  width: 10px;
  height: 10px;
  pointer-events: none;
  z-index: 9999;
  animation: confettiFall 2.5s ease-out forwards;
}

/* ===== RESPONSIVE ===== */
@media (max-width: 640px) {
  .app-container {
    padding: 12px;
  }

  .main-card {
    padding: 24px 18px;
    border-radius: 16px;
  }

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

  .category-grid {
    grid-template-columns: 1fr;
    max-height: 320px;
  }

  .quiz-question {
    font-size: 1.15rem;
  }

  .quiz-top-bar {
    flex-direction: column;
    align-items: stretch;
  }

  .stats-grid {
    grid-template-columns: 1fr 1fr;
  }

  .results-header .big-score {
    font-size: 3.2rem;
  }

  .btn {
    width: 100%;
  }
}