:root {
  --bg: #1a1f33;
  --card: #252b42;
  --accent: #6366f1;
  --accent-hover: #4f46e5;
  --muted: #a5b4fc;
  --success: #34d399;
  --danger: #f87171;
  --text: #f1f5f9;
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  font-family:
    "Inter",
    system-ui,
    -apple-system,
    "Segoe UI",
    Roboto,
    "Helvetica Neue",
    Arial,
    sans-serif;
  background: linear-gradient(180deg, #111827 0%, #1f2937 100%);
  color: var(--text);
  min-height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 10px;
}

.hidden {
  display: none;
}

.welcome {
  text-align: center;
  padding: 40px;
  background: var(--card);
  border-radius: 20px;
  box-shadow: 0 8px 32px rgba(0, 0, 0, 0.3);
  transform: translateY(0);
  transition: transform 0.3s ease;
  max-width: 500px;
  width: 100%;
}

.welcome:hover {
  transform: translateY(-5px);
}

.welcome h1 {
  margin-bottom: 20px;
  color: var(--accent);
  font-size: 2.2rem;
}

.welcome p {
  color: var(--muted);
  margin-bottom: 24px;
}

.category-container {
  display: flex;
  flex-direction: column;
  gap: 12px;
  margin: 24px 0;
}
.category-btn {
  font-size: 1rem;
}
main.card {
  background: var(--card);
  border-radius: 20px;
  padding: 24px;
  max-width: 680px;
  width: 100%;
  box-shadow: 0 10px 40px rgba(0, 0, 0, 0.2);
}

.card {
  background: linear-gradient(
    180deg,
    rgba(255, 255, 255, 0.03),
    rgba(255, 255, 255, 0.01)
  );
  border: 1px solid rgba(255, 255, 255, 0.06);
}

header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 20px;
}

header h1 {
  font-size: 1.8rem;
  margin: 0;
}

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

#back,
#categoryBackBtn {
  background: transparent;
  color: var(--accent);
  border: 2px solid var(--accent);
  padding: 10px 22px;
  border-radius: 24px;
  font-weight: 600;
  cursor: pointer;
  transition: all 0.2s;
  margin-bottom: 15px;
  box-shadow: none;
}

#back:hover,
#categoryBackBtn:hover {
  background: var(--accent);
  color: #fff;
  transform: translateY(-2px);
}

.question {
  padding: 20px;
  background: rgba(255, 255, 255, 0.03);
  border-radius: 15px;
  border: 1px solid rgba(255, 255, 255, 0.04);
  margin-bottom: 16px;
}

.q-text {
  font-size: 1.2rem;
  margin-bottom: 16px;
  line-height: 1.5;
}

.choices {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 12px;
}

.choice {
  padding: 14px 16px;
  border-radius: 24px;
  background: rgba(255, 255, 255, 0.02);
  border: 1px solid rgba(255, 255, 255, 0.06);
  cursor: pointer;
  transition: all 0.2s ease;
  text-align: left;
  font-size: 0.95rem;
  color: var(--text);
  font-weight: 500;
}

.choice:hover {
  transform: translateY(-2px);
  background: rgba(255, 255, 255, 0.05);
  box-shadow: 0 4px 15px rgba(0, 0, 0, 0.2);
}

.choice.selected {
  border-color: var(--accent);
  background: rgba(99, 102, 241, 0.1);
}

.choice.correct {
  background: rgba(52, 211, 153, 0.15) !important;
  border-color: var(--success) !important;
  color: #fff;
}

.choice.wrong {
  background: rgba(248, 113, 113, 0.15) !important;
  border-color: var(--danger) !important;
  color: #fff;
}

footer {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-top: 20px;
  flex-wrap: wrap;
  gap: 10px;
}

button {
  background: linear-gradient(45deg, var(--accent), var(--accent-hover));
  color: white;
  border: none;
  padding: 12px 26px;
  border-radius: 50px;
  cursor: pointer;
  font-weight: 600;
  transition: all 0.3s ease;
  box-shadow: 0 4px 15px rgba(99, 102, 241, 0.3);
}

button:hover {
  transform: translateY(-2px);
  box-shadow: 0 6px 20px rgba(99, 102, 241, 0.4);
}

button[disabled] {
  opacity: 0.5;
  cursor: not-allowed;
  transform: none;
  box-shadow: none;
}
#startBtn {
  font-size: 1.2rem;
}
#restartBtn {
  font-size: 1rem;
  background: transparent;
  border: 1px solid rgba(255, 255, 255, 0.1);
  box-shadow: none;
}

#restartBtn:hover {
  background: rgba(255, 255, 255, 0.05);
  box-shadow: 0 4px 15px rgba(0, 0, 0, 0.2);
}

.meta {
  color: var(--muted);
  font-size: 0.9rem;
}

.scoreboard {
  display: flex;
  gap: 16px;
  align-items: center;
  margin-bottom: 15px;
}

.small {
  font-size: 0.85rem;
  color: var(--muted);
}

@media (max-width: 560px) {
  .choices {
    grid-template-columns: 1fr;
  }
  .card {
    padding: 20px;
  }
  .welcome {
    padding: 24px;
  }
  #back,
  #categoryBackBtn {
    width: 100%;
    padding: 12px 0;
    font-size: 14px;
  }
  footer {
    flex-direction: column;
    align-items: stretch;
    text-align: center;
  }
}