@import url('https://fonts.googleapis.com/css2?family=Inter:wght@400;500;600;700;800;900&family=Roboto+Mono:wght@400;500;600;700&display=swap');

:root {
  /* ── BASE PALETTE ── */
  --bg-primary: #0B1C24;
  --bg-secondary: #0F2430;
  --bg-card: #102833;
  --bg-card-hover: #143340;
  --glass-border: rgba(28, 58, 70, 0.5);
  --glass-shadow: rgba(0, 0, 0, 0.4);

  /* ── TEXT ── */
  --text-primary: #E3ECF7;
  --text-secondary: #9AA6B6;
  --text-muted: #6B7A8D;

  /* ── NEON GREEN ── */
  --accent: #19F05A;
  --accent-dim: #15C74A;
  --accent-dark: #145A2B;
  --accent-fill: rgba(14, 106, 44, 0.4);
  --accent-glow: rgba(25, 240, 90, 0.25);
  --accent-glow-soft: rgba(25, 240, 90, 0.12);

  /* ── STATUS ── */
  --success: #19F05A;
  --success-bg: rgba(25, 240, 90, 0.12);
  --success-glow: rgba(25, 240, 90, 0.35);
  --error: #FF3B5C;
  --error-bg: rgba(255, 59, 92, 0.12);
  --error-glow: rgba(255, 59, 92, 0.35);
  --warning: #FFB830;
  --warning-bg: rgba(255, 184, 48, 0.12);
  --info: #3B9EFF;
  --info-bg: rgba(59, 158, 255, 0.12);

  /* ── GRADIENTS ── */
  --gradient-neon: linear-gradient(135deg, #19F05A 0%, #0AE08C 100%);
  --gradient-dark: linear-gradient(135deg, #145A2B 0%, #0B1C24 100%);
  --gradient-card: linear-gradient(145deg, #102833 0%, #0F2430 100%);
  --gradient-bg:
    radial-gradient(ellipse at 85% 15%, rgba(25, 240, 90, 0.08) 0%, transparent 50%),
    radial-gradient(ellipse at 10% 85%, rgba(25, 240, 90, 0.04) 0%, transparent 50%),
    radial-gradient(ellipse at 50% 50%, rgba(14, 106, 44, 0.03) 0%, transparent 70%);

  /* ── SPACING ── */
  --radius-sm: 10px;
  --radius-md: 16px;
  --radius-lg: 24px;
  --radius-xl: 32px;
  --transition: 0.3s cubic-bezier(0.4, 0, 0.2, 1);
  --transition-bounce: 0.5s cubic-bezier(0.34, 1.56, 0.64, 1);
}

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

body {
  font-family: 'Inter', -apple-system, sans-serif;
  background: var(--bg-primary);
  color: var(--text-primary);
  min-height: 100vh;
  overflow-x: hidden;
  -webkit-font-smoothing: antialiased;
}

body::before {
  content: '';
  position: fixed;
  inset: 0;
  background: var(--gradient-bg);
  z-index: 0;
  pointer-events: none;
}

/* Animated grid effect */
body::after {
  content: '';
  position: fixed;
  inset: 0;
  background-image:
    linear-gradient(rgba(25, 240, 90, 0.02) 1px, transparent 1px),
    linear-gradient(90deg, rgba(25, 240, 90, 0.02) 1px, transparent 1px);
  background-size: 60px 60px;
  z-index: 0;
  pointer-events: none;
}

/* ═══════════ LAYOUT ═══════════ */
.app {
  position: relative;
  z-index: 1;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  align-items: center;
  padding: 24px;
}

/* ═══════════ START SCREEN ═══════════ */
.start-screen {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  min-height: 90vh;
  text-align: center;
  animation: fadeInUp 0.8s ease-out;
}

.start-screen .logo {
  font-size: 72px;
  margin-bottom: 24px;
  filter: drop-shadow(0 0 30px rgba(25, 240, 90, 0.4));
  animation: float 3s ease-in-out infinite;
}

.start-screen h1 {
  font-size: clamp(30px, 5vw, 52px);
  font-weight: 900;
  color: var(--text-primary);
  margin-bottom: 8px;
  line-height: 1.15;
  letter-spacing: -0.5px;
}

.start-screen h1 .neon {
  color: var(--accent);
  text-shadow: 0 0 20px var(--accent-glow), 0 0 40px rgba(25, 240, 90, 0.15);
}

.start-screen .subtitle {
  font-size: clamp(16px, 2.5vw, 20px);
  color: var(--text-secondary);
  margin-bottom: 40px;
  max-width: 520px;
  line-height: 1.6;
}

.start-screen .stats-row {
  display: flex;
  gap: 16px;
  margin-bottom: 36px;
  flex-wrap: wrap;
  justify-content: center;
}

.stat-badge {
  background: var(--gradient-card);
  border: 1px solid var(--glass-border);
  border-radius: var(--radius-md);
  padding: 14px 22px;
  display: flex;
  align-items: center;
  gap: 8px;
}

.stat-badge .num {
  font-size: 24px;
  font-weight: 800;
  color: var(--accent);
  text-shadow: 0 0 12px var(--accent-glow);
  font-family: 'Roboto Mono', monospace;
}

.stat-badge .label {
  font-size: 13px;
  color: var(--text-secondary);
}

.mechanics-preview {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(150px, 1fr));
  gap: 10px;
  max-width: 660px;
  width: 100%;
  margin-bottom: 44px;
}

.mechanic-chip {
  background: rgba(25, 240, 90, 0.04);
  border: 1px solid rgba(25, 240, 90, 0.12);
  border-radius: var(--radius-sm);
  padding: 11px 16px;
  font-size: 13px;
  color: var(--text-secondary);
  display: flex;
  align-items: center;
  gap: 6px;
  transition: var(--transition);
}

.mechanic-chip:hover {
  background: rgba(25, 240, 90, 0.08);
  border-color: rgba(25, 240, 90, 0.35);
  color: var(--accent);
  transform: translateY(-2px);
  box-shadow: 0 4px 20px rgba(25, 240, 90, 0.1);
}

/* ═══════════ BUTTONS ═══════════ */
.btn-primary {
  background: var(--gradient-neon);
  color: #0B1C24;
  border: none;
  padding: 18px 52px;
  border-radius: var(--radius-lg);
  font-size: 18px;
  font-weight: 800;
  cursor: pointer;
  transition: var(--transition);
  box-shadow: 0 4px 30px var(--accent-glow), 0 0 60px rgba(25, 240, 90, 0.15);
  font-family: inherit;
  position: relative;
  overflow: hidden;
  letter-spacing: 0.3px;
}

.btn-primary::before {
  content: '';
  position: absolute;
  inset: 0;
  background: linear-gradient(135deg, rgba(255, 255, 255, 0.25) 0%, transparent 50%);
  opacity: 0;
  transition: var(--transition);
}

.btn-primary:hover {
  transform: translateY(-3px);
  box-shadow: 0 8px 40px var(--accent-glow), 0 0 80px rgba(25, 240, 90, 0.2);
}

.btn-primary:hover::before {
  opacity: 1;
}

.btn-primary:active {
  transform: translateY(-1px);
}

.btn-secondary {
  background: var(--bg-card);
  color: var(--text-primary);
  border: 1px solid var(--glass-border);
  padding: 12px 32px;
  border-radius: var(--radius-md);
  font-size: 15px;
  font-weight: 600;
  cursor: pointer;
  transition: var(--transition);
  font-family: inherit;
}

.btn-secondary:hover {
  background: var(--bg-card-hover);
  border-color: var(--accent);
  transform: translateY(-2px);
}

.btn-check {
  background: var(--gradient-neon);
  color: #0B1C24;
  border: none;
  padding: 14px 44px;
  border-radius: var(--radius-md);
  font-size: 16px;
  font-weight: 800;
  cursor: pointer;
  transition: var(--transition);
  font-family: inherit;
  box-shadow: 0 4px 24px var(--accent-glow);
  letter-spacing: 0.3px;
}

.btn-check:hover {
  transform: translateY(-2px);
  box-shadow: 0 6px 32px var(--accent-glow);
}

.btn-check:disabled {
  opacity: 0.3;
  cursor: not-allowed;
  transform: none;
  box-shadow: none;
}

.btn-next {
  background: var(--gradient-neon);
  color: #0B1C24;
  border: none;
  padding: 14px 44px;
  border-radius: var(--radius-md);
  font-size: 16px;
  font-weight: 800;
  cursor: pointer;
  transition: var(--transition);
  font-family: inherit;
  box-shadow: 0 4px 24px var(--accent-glow);
}

.btn-next:hover {
  transform: translateY(-2px);
  box-shadow: 0 6px 32px var(--accent-glow);
}

/* ═══════════ PROGRESS BAR ═══════════ */
.progress-container {
  width: 100%;
  max-width: 720px;
  margin-bottom: 24px;
  animation: fadeInDown 0.5s ease-out;
}

.progress-info {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 10px;
}

.progress-info .question-num {
  font-size: 14px;
  font-weight: 600;
  color: var(--text-secondary);
  font-family: 'Roboto Mono', monospace;
}

.progress-info .score {
  display: flex;
  align-items: center;
  gap: 6px;
  font-size: 14px;
  font-weight: 700;
  color: var(--accent);
  text-shadow: 0 0 10px var(--accent-glow);
  font-family: 'Roboto Mono', monospace;
}

.progress-info .streak {
  background: var(--warning-bg);
  color: var(--warning);
  padding: 3px 10px;
  border-radius: 20px;
  font-size: 12px;
  font-weight: 700;
  animation: neonPulse 1.5s ease-in-out infinite;
  border: 1px solid rgba(255, 184, 48, 0.3);
}

.progress-bar {
  height: 4px;
  background: rgba(25, 240, 90, 0.08);
  border-radius: 2px;
  overflow: hidden;
}

.progress-fill {
  height: 100%;
  background: var(--gradient-neon);
  border-radius: 2px;
  transition: width 0.5s cubic-bezier(0.4, 0, 0.2, 1);
  position: relative;
  box-shadow: 0 0 12px var(--accent-glow);
}

.progress-fill::after {
  content: '';
  position: absolute;
  right: 0;
  top: -3px;
  width: 10px;
  height: 10px;
  border-radius: 50%;
  background: var(--accent);
  box-shadow: 0 0 16px var(--accent-glow), 0 0 30px rgba(25, 240, 90, 0.3);
}

/* ═══════════ QUESTION CARD ═══════════ */
.question-card {
  width: 100%;
  max-width: 720px;
  background: var(--gradient-card);
  border: 1px solid var(--glass-border);
  border-radius: var(--radius-xl);
  padding: 40px;
  box-shadow:
    0 8px 40px var(--glass-shadow),
    0 0 60px rgba(25, 240, 90, 0.04),
    inset 0 1px 0 rgba(255, 255, 255, 0.03);
  animation: fadeInUp 0.5s ease-out;
  position: relative;
  overflow: hidden;
}

.question-card::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 2px;
  background: var(--gradient-neon);
  box-shadow: 0 0 20px var(--accent-glow);
}

.question-header {
  display: flex;
  align-items: center;
  gap: 12px;
  margin-bottom: 8px;
}

.question-type-badge {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  background: rgba(25, 240, 90, 0.08);
  border: 1px solid rgba(25, 240, 90, 0.2);
  color: var(--accent);
  padding: 5px 14px;
  border-radius: 20px;
  font-size: 11px;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 1px;
  font-family: 'Roboto Mono', monospace;
}

.question-topic {
  font-size: 12px;
  color: var(--text-muted);
  font-weight: 500;
}

.question-text {
  font-size: clamp(18px, 3vw, 23px);
  font-weight: 700;
  line-height: 1.5;
  margin: 16px 0 28px;
  color: var(--text-primary);
}

.question-hint {
  font-size: 13px;
  color: var(--text-muted);
  margin-bottom: 20px;
  padding: 12px 16px;
  background: rgba(25, 240, 90, 0.03);
  border-radius: var(--radius-sm);
  border-left: 3px solid var(--accent);
  box-shadow: -3px 0 12px rgba(25, 240, 90, 0.1);
}

/* ═══════════ CUSTOM CHECK / CROSS ICONS ═══════════ */
.icon-check,
.icon-cross {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 24px;
  height: 24px;
  flex-shrink: 0;
}

.icon-check svg {
  filter: drop-shadow(0 0 6px rgba(25, 240, 90, 0.5));
}

.icon-cross svg {
  filter: drop-shadow(0 0 6px rgba(255, 59, 92, 0.5));
}

/* ═══════════ SINGLE / MULTIPLE CHOICE ═══════════ */
.options-list {
  display: flex;
  flex-direction: column;
  gap: 12px;
  margin-bottom: 24px;
}

.option-item {
  display: flex;
  align-items: center;
  gap: 14px;
  padding: 16px 20px;
  background: rgba(255, 255, 255, 0.02);
  border: 1.5px solid rgba(28, 58, 70, 0.5);
  border-radius: var(--radius-md);
  cursor: pointer;
  transition: var(--transition);
  user-select: none;
  position: relative;
}

.option-item:hover {
  border-color: rgba(25, 240, 90, 0.3);
  background: rgba(25, 240, 90, 0.04);
  transform: translateX(4px);
}

.option-item.selected {
  border-color: var(--accent);
  background: rgba(25, 240, 90, 0.06);
  box-shadow: 0 0 20px rgba(25, 240, 90, 0.08);
}

.option-item.correct {
  border-color: var(--success) !important;
  background: var(--success-bg) !important;
  box-shadow: 0 0 24px var(--success-glow) !important;
  animation: correctGlow 0.6s ease-out;
}

.option-item.incorrect {
  border-color: var(--error) !important;
  background: var(--error-bg) !important;
  box-shadow: 0 0 24px var(--error-glow) !important;
  animation: shake 0.5s ease-out;
}

.option-item.disabled {
  pointer-events: none;
  opacity: 0.6;
}

.option-marker {
  width: 30px;
  height: 30px;
  border-radius: 50%;
  border: 2px solid rgba(154, 166, 182, 0.3);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 13px;
  font-weight: 700;
  color: var(--text-secondary);
  flex-shrink: 0;
  transition: var(--transition);
  font-family: 'Roboto Mono', monospace;
}

.option-item.selected .option-marker {
  border-color: var(--accent);
  background: var(--accent);
  color: #0B1C24;
  box-shadow: 0 0 12px var(--accent-glow);
}

.option-item.correct .option-marker {
  border-color: var(--success);
  background: var(--success);
  color: #0B1C24;
  box-shadow: 0 0 16px var(--success-glow);
}

.option-item.incorrect .option-marker {
  border-color: var(--error);
  background: var(--error);
  color: white;
  box-shadow: 0 0 16px var(--error-glow);
}

.option-marker-multi {
  border-radius: 8px;
}

.option-text {
  font-size: 15px;
  font-weight: 500;
  line-height: 1.4;
}

/* ═══════════ MATCHING ═══════════ */
.matching-container {
  display: flex;
  gap: 20px;
  margin-bottom: 24px;
  flex-wrap: wrap;
}

.matching-column {
  flex: 1;
  min-width: 200px;
  display: flex;
  flex-direction: column;
  gap: 10px;
}

.matching-column-title {
  font-size: 11px;
  font-weight: 700;
  color: var(--accent);
  text-transform: uppercase;
  letter-spacing: 2px;
  margin-bottom: 4px;
  text-align: center;
  font-family: 'Roboto Mono', monospace;
}

.matching-item {
  padding: 14px 16px;
  background: rgba(25, 240, 90, 0.02);
  border: 1.5px solid rgba(28, 58, 70, 0.5);
  border-radius: var(--radius-md);
  font-size: 14px;
  font-weight: 500;
  cursor: pointer;
  transition: var(--transition);
  text-align: center;
  user-select: none;
}

.matching-item:hover {
  border-color: rgba(25, 240, 90, 0.3);
  background: rgba(25, 240, 90, 0.05);
}

.matching-item.active {
  border-color: var(--accent);
  background: rgba(25, 240, 90, 0.1);
  box-shadow: 0 0 24px var(--accent-glow);
}

.matching-item.matched {
  border-color: var(--success);
  background: var(--success-bg);
  cursor: default;
  box-shadow: 0 0 16px rgba(25, 240, 90, 0.15);
}

.matching-item.wrong {
  border-color: var(--error);
  background: var(--error-bg);
  animation: shake 0.4s ease-out;
  box-shadow: 0 0 16px var(--error-glow);
}

.matching-item .match-num {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 22px;
  height: 22px;
  border-radius: 50%;
  background: var(--success);
  color: #0B1C24;
  font-size: 11px;
  font-weight: 800;
  margin-right: 8px;
  box-shadow: 0 0 10px var(--accent-glow);
  font-family: 'Roboto Mono', monospace;
}

/* ═══════════ FLASHCARD ═══════════ */
.flashcard-container {
  perspective: 1000px;
  margin: 20px auto 24px;
  width: 100%;
  max-width: 440px;
  height: 250px;
}

.flashcard {
  width: 100%;
  height: 100%;
  position: relative;
  transform-style: preserve-3d;
  transition: transform 0.7s cubic-bezier(0.4, 0, 0.2, 1);
  cursor: pointer;
}

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

.flashcard-face {
  position: absolute;
  inset: 0;
  backface-visibility: hidden;
  border-radius: var(--radius-lg);
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  padding: 28px;
  text-align: center;
}

.flashcard-front {
  background: linear-gradient(145deg, rgba(25, 240, 90, 0.06), rgba(25, 240, 90, 0.02));
  border: 1.5px solid rgba(25, 240, 90, 0.2);
  box-shadow: 0 0 40px rgba(25, 240, 90, 0.06);
}

.flashcard-front .card-label {
  font-size: 11px;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 2px;
  color: var(--accent);
  margin-bottom: 18px;
  font-family: 'Roboto Mono', monospace;
}

.flashcard-front .card-text {
  font-size: 16px;
  line-height: 1.6;
  color: var(--text-primary);
}

.flashcard-front .tap-hint {
  margin-top: 18px;
  font-size: 12px;
  color: var(--text-muted);
  display: flex;
  align-items: center;
  gap: 6px;
  animation: neonPulse 2s infinite;
}

.flashcard-back {
  background: linear-gradient(145deg, rgba(25, 240, 90, 0.1), rgba(14, 106, 44, 0.08));
  border: 1.5px solid rgba(25, 240, 90, 0.35);
  transform: rotateY(180deg);
  box-shadow: 0 0 40px rgba(25, 240, 90, 0.1);
}

.flashcard-back .card-label {
  font-size: 11px;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 2px;
  color: var(--accent);
  margin-bottom: 12px;
  font-family: 'Roboto Mono', monospace;
}

.flashcard-back .answer-text {
  font-size: 30px;
  font-weight: 900;
  color: var(--accent);
  text-shadow: 0 0 24px var(--accent-glow), 0 0 48px rgba(25, 240, 90, 0.15);
}

.flashcard-actions {
  display: flex;
  gap: 14px;
  justify-content: center;
  margin-top: 20px;
}

.flashcard-actions .btn-knew,
.flashcard-actions .btn-didnt {
  padding: 14px 30px;
  border-radius: var(--radius-md);
  font-size: 15px;
  font-weight: 700;
  cursor: pointer;
  border: 2px solid;
  transition: var(--transition);
  font-family: inherit;
  display: flex;
  align-items: center;
  gap: 8px;
}

.btn-knew {
  background: var(--success-bg);
  color: var(--success);
  border-color: rgba(25, 240, 90, 0.3) !important;
}

.btn-knew:hover {
  background: rgba(25, 240, 90, 0.18);
  border-color: var(--accent) !important;
  transform: translateY(-2px);
  box-shadow: 0 4px 20px rgba(25, 240, 90, 0.2);
}

.btn-didnt {
  background: var(--error-bg);
  color: var(--error);
  border-color: rgba(255, 59, 92, 0.3) !important;
}

.btn-didnt:hover {
  background: rgba(255, 59, 92, 0.18);
  border-color: var(--error) !important;
  transform: translateY(-2px);
  box-shadow: 0 4px 20px rgba(255, 59, 92, 0.2);
}

/* ═══════════ FILL IN BLANK ═══════════ */
.fillin-container {
  margin-bottom: 24px;
}

.fillin-text {
  font-size: 18px;
  line-height: 1.8;
  color: var(--text-primary);
  margin-bottom: 20px;
}

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

.fillin-input {
  flex: 1;
  min-width: 200px;
  padding: 14px 18px;
  background: rgba(25, 240, 90, 0.03);
  border: 2px solid rgba(28, 58, 70, 0.5);
  border-radius: var(--radius-md);
  color: var(--text-primary);
  font-size: 16px;
  font-family: 'Roboto Mono', monospace;
  font-weight: 600;
  transition: var(--transition);
  outline: none;
}

.fillin-input:focus {
  border-color: var(--accent);
  box-shadow: 0 0 24px var(--accent-glow);
}

.fillin-input::placeholder {
  color: var(--text-muted);
  font-family: 'Inter', sans-serif;
  font-weight: 400;
}

.fillin-input.correct {
  border-color: var(--success);
  background: var(--success-bg);
  box-shadow: 0 0 20px var(--success-glow);
}

.fillin-input.incorrect {
  border-color: var(--error);
  background: var(--error-bg);
  box-shadow: 0 0 20px var(--error-glow);
}

.fillin-label {
  font-size: 12px;
  color: var(--accent);
  margin-bottom: 6px;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.5px;
  font-family: 'Roboto Mono', monospace;
}

/* ═══════════ CATEGORIZE ═══════════ */
.categorize-container {
  margin-bottom: 24px;
}

.categorize-items-pool {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  padding: 18px;
  background: rgba(25, 240, 90, 0.02);
  border: 2px dashed rgba(25, 240, 90, 0.12);
  border-radius: var(--radius-md);
  min-height: 56px;
  margin-bottom: 20px;
  justify-content: center;
}

.categorize-item {
  padding: 10px 18px;
  background: rgba(25, 240, 90, 0.06);
  border: 1.5px solid rgba(25, 240, 90, 0.15);
  border-radius: var(--radius-sm);
  font-size: 14px;
  font-weight: 600;
  cursor: grab;
  transition: var(--transition);
  user-select: none;
  touch-action: none;
}

.categorize-item:hover {
  background: rgba(25, 240, 90, 0.12);
  border-color: var(--accent);
  transform: translateY(-2px);
  box-shadow: 0 4px 16px rgba(25, 240, 90, 0.1);
}

.categorize-item:active {
  cursor: grabbing;
}

.categorize-item.dragging {
  opacity: 0.4;
}

.categorize-item.correct {
  background: var(--success-bg);
  border-color: var(--success);
  cursor: default;
  box-shadow: 0 0 16px rgba(25, 240, 90, 0.15);
}

.categorize-item.incorrect {
  background: var(--error-bg);
  border-color: var(--error);
  animation: shake 0.4s;
  box-shadow: 0 0 16px var(--error-glow);
}

.categorize-zones {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
  gap: 16px;
}

.categorize-zone {
  background: rgba(25, 240, 90, 0.02);
  border: 2px dashed rgba(28, 58, 70, 0.5);
  border-radius: var(--radius-md);
  padding: 16px;
  min-height: 120px;
  transition: var(--transition);
}

.categorize-zone.drag-over {
  border-color: var(--accent);
  background: rgba(25, 240, 90, 0.06);
  box-shadow: 0 0 30px rgba(25, 240, 90, 0.08);
}

.categorize-zone-title {
  font-size: 12px;
  font-weight: 700;
  color: var(--accent);
  margin-bottom: 12px;
  text-align: center;
  text-transform: uppercase;
  letter-spacing: 1.5px;
  font-family: 'Roboto Mono', monospace;
}

.categorize-zone-items {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  justify-content: center;
}

/* ═══════════ TRUE/FALSE ═══════════ */
.truefalse-container {
  margin-bottom: 24px;
}

.truefalse-statement {
  font-size: 20px;
  font-weight: 600;
  line-height: 1.6;
  text-align: center;
  padding: 32px;
  background: rgba(25, 240, 90, 0.02);
  border-radius: var(--radius-lg);
  border: 1px solid var(--glass-border);
  margin-bottom: 24px;
}

.truefalse-buttons {
  display: flex;
  gap: 16px;
  justify-content: center;
}

.btn-true,
.btn-false {
  flex: 1;
  max-width: 220px;
  padding: 20px 32px;
  border-radius: var(--radius-md);
  font-size: 18px;
  font-weight: 800;
  cursor: pointer;
  border: 2px solid;
  transition: var(--transition);
  font-family: inherit;
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 10px;
}

.btn-true {
  background: rgba(25, 240, 90, 0.06);
  color: var(--success);
  border-color: rgba(25, 240, 90, 0.2);
}

.btn-true:hover {
  background: rgba(25, 240, 90, 0.12);
  border-color: var(--accent);
  transform: translateY(-3px);
  box-shadow: 0 6px 28px rgba(25, 240, 90, 0.2);
}

.btn-false {
  background: rgba(255, 59, 92, 0.06);
  color: var(--error);
  border-color: rgba(255, 59, 92, 0.2);
}

.btn-false:hover {
  background: rgba(255, 59, 92, 0.12);
  border-color: var(--error);
  transform: translateY(-3px);
  box-shadow: 0 6px 28px rgba(255, 59, 92, 0.2);
}

.btn-true.correct,
.btn-false.correct {
  background: var(--success-bg);
  border-color: var(--success);
  box-shadow: 0 0 36px var(--success-glow);
}

.btn-true.incorrect,
.btn-false.incorrect {
  background: var(--error-bg);
  border-color: var(--error);
  box-shadow: 0 0 36px var(--error-glow);
  animation: shake 0.5s;
}

.btn-true.disabled,
.btn-false.disabled {
  pointer-events: none;
  opacity: 0.5;
}

/* ═══════════ ORDERING ═══════════ */
.ordering-container {
  margin-bottom: 24px;
}

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

.ordering-item {
  display: flex;
  align-items: center;
  gap: 14px;
  padding: 16px 20px;
  background: rgba(25, 240, 90, 0.02);
  border: 1.5px solid rgba(28, 58, 70, 0.5);
  border-radius: var(--radius-md);
  cursor: grab;
  transition: var(--transition);
  user-select: none;
  touch-action: none;
}

.ordering-item:hover {
  border-color: rgba(25, 240, 90, 0.3);
  background: rgba(25, 240, 90, 0.04);
}

.ordering-item:active {
  cursor: grabbing;
}

.ordering-item.selected {
  border-color: var(--accent);
  background: rgba(25, 240, 90, 0.06);
  box-shadow: 0 0 20px rgba(25, 240, 90, 0.08);
}

.ordering-item.dragging {
  opacity: 0.3;
  border-style: dashed;
  border-color: var(--accent);
}

.ordering-item.drag-over-top {
  border-top: 3px solid var(--accent);
}

.ordering-item.drag-over-bottom {
  border-bottom: 3px solid var(--accent);
}

.ordering-item.correct {
  border-color: var(--success);
  background: var(--success-bg);
  box-shadow: 0 0 16px rgba(25, 240, 90, 0.12);
}

.ordering-item.incorrect {
  border-color: var(--error);
  background: var(--error-bg);
  box-shadow: 0 0 16px var(--error-glow);
}

.ordering-num {
  width: 32px;
  height: 32px;
  border-radius: 50%;
  background: rgba(25, 240, 90, 0.08);
  border: 1.5px solid rgba(25, 240, 90, 0.2);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 14px;
  font-weight: 700;
  color: var(--accent);
  flex-shrink: 0;
  font-family: 'Roboto Mono', monospace;
}

.ordering-item.correct .ordering-num {
  background: var(--success);
  color: #0B1C24;
  border-color: var(--success);
  box-shadow: 0 0 12px var(--accent-glow);
}

.ordering-item.incorrect .ordering-num {
  background: var(--error);
  color: white;
  border-color: var(--error);
  box-shadow: 0 0 12px var(--error-glow);
}

.ordering-text {
  font-size: 15px;
  font-weight: 500;
}

.ordering-handle {
  margin-left: auto;
  color: var(--text-muted);
  font-size: 18px;
  flex-shrink: 0;
  opacity: 0.5;
}

/* ═══════════ FEEDBACK ═══════════ */
.feedback {
  padding: 16px 20px;
  border-radius: var(--radius-md);
  margin-top: 16px;
  font-size: 14px;
  font-weight: 500;
  line-height: 1.5;
  animation: fadeInUp 0.3s ease-out;
  display: flex;
  align-items: flex-start;
  gap: 12px;
}

.feedback.correct {
  background: var(--success-bg);
  border: 1px solid rgba(25, 240, 90, 0.2);
  color: var(--success);
  box-shadow: 0 0 24px rgba(25, 240, 90, 0.08);
}

.feedback.incorrect {
  background: var(--error-bg);
  border: 1px solid rgba(255, 59, 92, 0.2);
  color: var(--error);
  box-shadow: 0 0 24px rgba(255, 59, 92, 0.08);
}

.feedback.partial {
  background: var(--warning-bg);
  border: 1px solid rgba(255, 184, 48, 0.2);
  color: var(--warning);
}

.feedback-icon {
  font-size: 20px;
  flex-shrink: 0;
}

/* ═══════════ QUESTION ACTIONS ═══════════ */
.question-actions {
  display: flex;
  justify-content: flex-end;
  gap: 12px;
  margin-top: 20px;
}

/* ═══════════ RESULTS SCREEN ═══════════ */
.results-screen {
  display: flex;
  flex-direction: column;
  align-items: center;
  min-height: 90vh;
  padding: 40px 20px;
  animation: fadeInUp 0.8s ease-out;
  width: 100%;
  max-width: 720px;
}

.results-title {
  font-size: clamp(28px, 5vw, 44px);
  font-weight: 900;
  color: var(--text-primary);
  margin-bottom: 32px;
  text-align: center;
}

.results-title .neon {
  color: var(--accent);
  text-shadow: 0 0 20px var(--accent-glow);
}

.results-circle-container {
  position: relative;
  width: 220px;
  height: 220px;
  margin-bottom: 32px;
}

.results-circle {
  width: 220px;
  height: 220px;
  transform: rotate(-90deg);
}

.results-circle-bg {
  fill: none;
  stroke: rgba(25, 240, 90, 0.06);
  stroke-width: 8;
}

.results-circle-fill {
  fill: none;
  stroke: url(#gradient);
  stroke-width: 8;
  stroke-linecap: round;
  transition: stroke-dashoffset 2s cubic-bezier(0.4, 0, 0.2, 1);
  filter: drop-shadow(0 0 8px rgba(25, 240, 90, 0.3));
}

.results-percent {
  position: absolute;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  font-size: 52px;
  font-weight: 900;
  font-family: 'Roboto Mono', monospace;
  color: var(--accent);
  text-shadow: 0 0 24px var(--accent-glow);
}

.results-rank {
  font-size: 26px;
  font-weight: 800;
  margin-bottom: 8px;
  text-align: center;
  display: flex;
  align-items: center;
  gap: 12px;
  justify-content: center;
}

.results-rank .rank-icon {
  font-size: 40px;
  filter: drop-shadow(0 0 12px rgba(25, 240, 90, 0.4));
}

.results-rank-desc {
  font-size: 15px;
  color: var(--text-secondary);
  margin-bottom: 36px;
  text-align: center;
}

.results-stats {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 14px;
  width: 100%;
  margin-bottom: 36px;
}

.results-stat {
  text-align: center;
  padding: 22px;
  background: var(--gradient-card);
  border: 1px solid var(--glass-border);
  border-radius: var(--radius-md);
}

.results-stat .stat-value {
  font-size: 30px;
  font-weight: 800;
  margin-bottom: 4px;
  font-family: 'Roboto Mono', monospace;
}

.results-stat .stat-label {
  font-size: 11px;
  color: var(--text-muted);
  text-transform: uppercase;
  letter-spacing: 1px;
  font-family: 'Roboto Mono', monospace;
}

.results-errors {
  width: 100%;
  margin-bottom: 32px;
}

.results-errors h3 {
  font-size: 16px;
  font-weight: 700;
  margin-bottom: 16px;
  color: var(--text-secondary);
  display: flex;
  align-items: center;
  gap: 8px;
}

.error-item {
  padding: 16px;
  background: var(--gradient-card);
  border: 1px solid var(--glass-border);
  border-radius: var(--radius-md);
  margin-bottom: 10px;
  border-left: 3px solid var(--error);
}

.error-item .error-q {
  font-size: 14px;
  font-weight: 600;
  margin-bottom: 6px;
}

.error-item .error-correct {
  font-size: 13px;
  color: var(--accent);
}

.results-actions {
  display: flex;
  gap: 16px;
  flex-wrap: wrap;
  justify-content: center;
}

/* ═══════════ CONFETTI ═══════════ */
.confetti-piece {
  position: fixed;
  z-index: 1000;
  pointer-events: none;
}

/* ═══════════ SOUND TOGGLE ═══════════ */
.sound-toggle {
  position: fixed;
  top: 20px;
  right: 20px;
  background: var(--bg-card);
  border: 1px solid var(--glass-border);
  border-radius: 50%;
  width: 44px;
  height: 44px;
  display: flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  font-size: 20px;
  z-index: 100;
  transition: var(--transition);
  color: var(--text-secondary);
}

.sound-toggle:hover {
  background: var(--bg-card-hover);
  border-color: var(--accent);
  transform: scale(1.1);
  box-shadow: 0 0 20px rgba(25, 240, 90, 0.1);
}

/* ═══════════ SCORE POPUP ═══════════ */
.score-popup {
  position: absolute;
  top: 0;
  right: 20px;
  font-size: 20px;
  font-weight: 900;
  color: var(--accent);
  pointer-events: none;
  animation: scorePopup 1s ease-out forwards;
  text-shadow: 0 0 16px var(--accent-glow);
  font-family: 'Roboto Mono', monospace;
}

.score-popup.streak-bonus {
  color: var(--warning);
  font-size: 24px;
  text-shadow: 0 0 16px rgba(255, 184, 48, 0.4);
}

/* ═══════════ ANIMATIONS ═══════════ */
@keyframes fadeInUp {
  from {
    opacity: 0;
    transform: translateY(24px);
  }

  to {
    opacity: 1;
    transform: translateY(0);
  }
}

@keyframes fadeInDown {
  from {
    opacity: 0;
    transform: translateY(-16px);
  }

  to {
    opacity: 1;
    transform: translateY(0);
  }
}

@keyframes float {

  0%,
  100% {
    transform: translateY(0);
  }

  50% {
    transform: translateY(-14px);
  }
}

@keyframes shake {

  0%,
  100% {
    transform: translateX(0);
  }

  20% {
    transform: translateX(-8px);
  }

  40% {
    transform: translateX(8px);
  }

  60% {
    transform: translateX(-6px);
  }

  80% {
    transform: translateX(4px);
  }
}

@keyframes correctGlow {
  0% {
    box-shadow: 0 0 0 0 rgba(25, 240, 90, 0.4);
  }

  50% {
    box-shadow: 0 0 0 14px rgba(25, 240, 90, 0);
  }

  100% {
    box-shadow: 0 0 24px var(--success-glow);
  }
}

@keyframes neonPulse {

  0%,
  100% {
    opacity: 1;
  }

  50% {
    opacity: 0.5;
  }
}

@keyframes scorePopup {
  0% {
    opacity: 0;
    transform: translateY(0) scale(0.5);
  }

  50% {
    opacity: 1;
    transform: translateY(-24px) scale(1.2);
  }

  100% {
    opacity: 0;
    transform: translateY(-48px) scale(0.8);
  }
}

/* ═══════════ RESPONSIVE ═══════════ */
@media (max-width: 600px) {
  .app {
    padding: 14px;
  }

  .question-card {
    padding: 24px 18px;
    border-radius: var(--radius-lg);
  }

  .matching-container {
    flex-direction: column;
  }

  .truefalse-buttons {
    flex-direction: column;
    align-items: center;
  }

  .btn-true,
  .btn-false {
    max-width: 100%;
  }

  .flashcard-container {
    height: 210px;
  }

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

  .mechanics-preview {
    grid-template-columns: repeat(2, 1fr);
  }

  .fillin-input-row {
    flex-direction: column;
  }
}

/* ═══════════ TIMER BAR ═══════════ */
.timer-container {
  width: 100%;
  margin-top: 12px;
  margin-bottom: -8px;
}

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

.timer-bar {
  flex: 1;
  height: 4px;
  background: rgba(25, 240, 90, 0.08);
  border-radius: 2px;
  overflow: hidden;
}

.timer-fill {
  height: 100%;
  background: var(--gradient-neon);
  border-radius: 2px;
  transition: width 0.3s linear;
  box-shadow: 0 0 10px var(--accent-glow);
}

.timer-fill.warning {
  background: linear-gradient(135deg, #FFB830, #FF8C00);
  box-shadow: 0 0 10px rgba(255, 184, 48, 0.4);
}

.timer-fill.danger {
  background: linear-gradient(135deg, #FF3B5C, #FF1744);
  box-shadow: 0 0 14px var(--error-glow);
  animation: timerPulse 0.5s ease-in-out infinite;
}

.timer-text {
  font-size: 13px;
  font-weight: 700;
  font-family: 'Roboto Mono', monospace;
  color: var(--accent);
  min-width: 36px;
  text-align: right;
}

.timer-text.warning {
  color: var(--warning);
}

.timer-text.danger {
  color: var(--error);
  animation: neonPulse 0.5s infinite;
}

.timer-bonus {
  font-size: 11px;
  color: var(--text-muted);
  text-align: right;
  margin-top: 4px;
  font-family: 'Roboto Mono', monospace;
}

@keyframes timerPulse {

  0%,
  100% {
    opacity: 1;
    box-shadow: 0 0 14px var(--error-glow);
  }

  50% {
    opacity: 0.7;
    box-shadow: 0 0 24px var(--error-glow);
  }
}

/* ═══════════ SLIDE TRANSITIONS ═══════════ */
.question-card.slide-out {
  animation: slideOut 0.3s ease-in forwards;
}

.question-card.slide-in {
  animation: slideIn 0.4s ease-out forwards;
}

@keyframes slideOut {
  from {
    opacity: 1;
    transform: translateX(0) scale(1);
  }

  to {
    opacity: 0;
    transform: translateX(-60px) scale(0.95);
  }
}

@keyframes slideIn {
  from {
    opacity: 0;
    transform: translateX(60px) scale(0.95);
  }

  to {
    opacity: 1;
    transform: translateX(0) scale(1);
  }
}

/* ═══════════ MIDWAY SCREEN ═══════════ */
.midway-screen {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  min-height: 60vh;
  text-align: center;
  animation: fadeInUp 0.6s ease-out;
  width: 100%;
  max-width: 720px;
}

.midway-screen .midway-emoji {
  font-size: 80px;
  margin-bottom: 24px;
  animation: float 2s ease-in-out infinite;
  filter: drop-shadow(0 0 20px rgba(255, 184, 48, 0.4));
}

.midway-screen h2 {
  font-size: clamp(24px, 4vw, 38px);
  font-weight: 900;
  margin-bottom: 12px;
  color: var(--text-primary);
}

.midway-screen h2 .neon {
  color: var(--accent);
  text-shadow: 0 0 16px var(--accent-glow);
}

.midway-screen .midway-stats {
  display: flex;
  gap: 20px;
  margin: 24px 0 36px;
  flex-wrap: wrap;
  justify-content: center;
}

.midway-screen .midway-msg {
  font-size: 16px;
  color: var(--text-secondary);
  margin-bottom: 32px;
  line-height: 1.6;
  max-width: 400px;
}

/* ═══════════ SHARE CARD ═══════════ */
.share-section {
  margin-top: 16px;
  text-align: center;
}

.btn-share {
  background: var(--bg-card);
  color: var(--text-primary);
  border: 1px solid var(--glass-border);
  padding: 14px 36px;
  border-radius: var(--radius-md);
  font-size: 15px;
  font-weight: 700;
  cursor: pointer;
  transition: var(--transition);
  font-family: inherit;
  display: inline-flex;
  align-items: center;
  gap: 8px;
}

.btn-share:hover {
  border-color: var(--accent);
  background: var(--bg-card-hover);
  transform: translateY(-2px);
  box-shadow: 0 4px 20px rgba(25, 240, 90, 0.1);
}

.share-preview {
  margin-top: 16px;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 12px;
  animation: fadeInUp 0.3s ease-out;
}

.share-preview canvas {
  border-radius: var(--radius-md);
  box-shadow: 0 8px 30px var(--glass-shadow);
  max-width: 100%;
}

.btn-download {
  background: var(--gradient-neon);
  color: #0B1C24;
  border: none;
  padding: 12px 32px;
  border-radius: var(--radius-md);
  font-size: 14px;
  font-weight: 800;
  cursor: pointer;
  transition: var(--transition);
  font-family: inherit;
}

.btn-download:hover {
  transform: translateY(-2px);
  box-shadow: 0 4px 20px var(--accent-glow);
}

/* ═══════════ RETRY ERRORS BUTTON ═══════════ */
.btn-retry-errors {
  background: var(--error-bg);
  color: var(--error);
  border: 1px solid rgba(255, 59, 92, 0.3);
  padding: 14px 36px;
  border-radius: var(--radius-md);
  font-size: 15px;
  font-weight: 700;
  cursor: pointer;
  transition: var(--transition);
  font-family: inherit;
  display: inline-flex;
  align-items: center;
  gap: 8px;
}

.btn-retry-errors:hover {
  background: rgba(255, 59, 92, 0.18);
  border-color: var(--error);
  transform: translateY(-2px);
  box-shadow: 0 4px 20px rgba(255, 59, 92, 0.2);
}

.hidden {
  display: none !important;
}