:root {
  --primary-color: #6366f1;
  --primary-hover: #4f46e5;
  --success-color: #10b981;
  --error-color: #ef4444;
  --background: #f8fafc;
  --card-bg: #ffffff;
  --text-primary: #1e293b;
  --text-secondary: #64748b;
  --border-color: #e2e8f0;
  
  font-family: 'Inter', system-ui, -apple-system, sans-serif;
  line-height: 1.5;
  font-weight: 400;
  
  color-scheme: light dark;
  background-color: var(--background);
  color: var(--text-primary);
}

/* Animations */
@keyframes slideIn {
  from {
    transform: translateY(20px);
    opacity: 0;
  }
  to {
    transform: translateY(0);
    opacity: 1;
  }
}

@keyframes fadeIn {
  from { opacity: 0; }
  to { opacity: 1; }
}

@keyframes scaleIn {
  from {
    transform: scale(0.95);
    opacity: 0;
  }
  to {
    transform: scale(1);
    opacity: 1;
  }
}

@keyframes pulse {
  0% { transform: scale(1); }
  50% { transform: scale(1.05); }
  100% { transform: scale(1); }
}

body {
  margin: 0;
  min-height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
  background-color:whitesmoke;
  /* background: linear-gradient(135deg, #c6e5fa 0%, #e0f2fe 100%); */
  padding: 1rem;
  font-family: 'Trebuchet MS', 'Lucida Sans Unicode', 'Lucida Grande', 'Lucida Sans', Arial, sans-serif;
}

#app {
  width: 100%;
  max-width: 700px;
  margin: 0 auto;
}

.quiz-container {
  background: var(--card-bg);
  border-radius: 24px;
  box-shadow: 0 20px 25px -5px rgba(0, 0, 0, 0.1),
              0 8px 10px -6px rgba(0, 0, 0, 0.05);
  padding: 2rem;
  animation: scaleIn 0.5s ease-out;
}

.quiz-header {
  text-align: center;
  margin-bottom: 2.5rem;
}

.quiz-header h2 {
  font-size: 2rem;
  font-weight: 700;
  color: var(--text-primary);
  margin: 0 0 1rem;
  font-family: 'Trebuchet MS', 'Lucida Sans Unicode', 'Lucida Grande', 'Lucida Sans', Arial, sans-serif;
}

.progress {
  background: var(--background);
  border-radius: 9999px;
  height: 8px;
  overflow: hidden;
  position: relative;
  width: 100%;
  margin-top: 1.5rem;
}

.progress-bar {
  background: var(--primary-color);
  height: 100%;
  transition: width 0.3s ease;
}

.question {
  font-size: 1.25rem;
  font-weight: 600;
  color: var(--text-primary);
  margin-bottom: 2rem;
  line-height: 1.6;
  animation: slideIn 0.5s ease-out;
}

.options {
  display: grid;
  gap: 1rem;
  margin-bottom: 2rem;
}

.option {
  background: var(--background);
  border: 2px solid var(--border-color);
  border-radius: 12px;
  padding: 1rem 1.5rem;
  font-size: 1rem;
  font-weight: 500;
  color: var(--text-primary);
  cursor: pointer;
  transition: all 0.2s ease;
  position: relative;
  text-align: left;
  display: flex;
  align-items: center;
  animation: slideIn 0.5s ease-out backwards;
}

.option:before {
  content: '';
  width: 20px;
  height: 20px;
  border: 2px solid var(--border-color);
  border-radius: 50%;
  margin-right: 1rem;
  transition: all 0.2s ease;
}

.option:hover:not(:disabled) {
  border-color: var(--primary-color);
  background: #f8fafc;
  transform: translateY(-2px);
}

.option:hover:not(:disabled):before {
  border-color: var(--primary-color);
}

.option.correct {
  background: #ecfdf5;
  border-color: var(--success-color);
  color: #065f46;
}

.option.correct:before {
  background: var(--success-color);
  border-color: var(--success-color);
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 24 24' fill='white'%3E%3Cpath d='M20.285 2l-11.285 11.567-5.286-5.011-3.714 3.716 9 8.728 15-15.285z'/%3E%3C/svg%3E");
  background-size: 12px;
  background-repeat: no-repeat;
  background-position: center;
}

.option.incorrect {
  background: #fef2f2;
  border-color: var(--error-color);
  color: #991b1b;
}

.option.incorrect:before {
  background: var(--error-color);
  border-color: var(--error-color);
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 24 24' fill='white'%3E%3Cpath d='M19 6.41L17.59 5 12 10.59 6.41 5 5 6.41 10.59 12 5 17.59 6.41 19 12 13.41 17.59 19 19 17.59 13.41 12z'/%3E%3C/svg%3E");
  background-size: 12px;
  background-repeat: no-repeat;
  background-position: center;
}

.next-btn {
  background: var(--primary-color);
  color: white;
  border: none;
  border-radius: 12px;
  padding: 1rem 2rem;
  font-size: 1rem;
  font-weight: 600;
  cursor: pointer;
  transition: all 0.2s ease;
  width: 100%;
  max-width: 200px;
  margin: 0 auto;
  display: block;
}

.next-btn:hover {
  background: var(--primary-hover);
  transform: translateY(-2px);
  box-shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.1),
              0 2px 4px -1px rgba(0, 0, 0, 0.06);
}

.result-content {
  text-align: center;
  padding: 2.5rem;
  border-radius: 16px;
  animation: scaleIn 0.6s ease-out;
}

.result-content.pass {
  background: #ecfdf5;
  border: 2px solid var(--success-color);
}

.result-content.fail {
  background: #fef2f2;
  border: 2px solid var(--error-color);
}

.result-content h2 {
  font-size: 2rem;
  margin-bottom: 1rem;
  animation: pulse 2s infinite;
}

.result-content p {
  font-size: 1.25rem;
  margin: 0.5rem 0;
  opacity: 0.9;
}

.restart-btn, .home-btn {
  background: var(--primary-color);
  color: white;
  border: none;
  border-radius: 32px;
  padding: 1rem;
  font-size: 1rem;
  font-weight: 600;
  cursor: pointer;
  transition: all 0.2s ease;
  margin-top: 2rem;
}

.restart-btn:hover {
  background: var(--primary-hover);
  transform: translateY(-2px);
  box-shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.1),
              0 2px 4px -1px rgba(0, 0, 0, 0.06);
}

@media (prefers-color-scheme: dark) {
  :root {
    --background: #0f172a;
    --card-bg: #1e293b;
    --text-primary: #f1f5f9;
    --text-secondary: #94a3b8;
    --border-color: #334155;
  }

  body {
    background: linear-gradient(135deg, #0f172a 0%, #1e293b 100%);
  }

  .option {
    background: #1e293b;
  }

  .option:hover:not(:disabled) {
    background: #334155;
  }

  .option.correct {
    background: #064e3b;
    color: #ecfdf5;
  }

  .option.incorrect {
    background: #7f1d1d;
    color: #fef2f2;
  }
}