*, *::before, *::after { box-sizing: border-box; font-family: 'Segoe UI', 'Helvetica Neue', Arial, sans-serif; }

:root {
  --hue-neutral: 200;
  --hue-wrong: 0;
  --hue-correct: 145;
  --hue: var(--hue-neutral);
}

html, body { margin: 0; padding: 0; }

body {
  --hue: var(--hue-neutral);
  background-color: hsl(var(--hue), 100%, 20%);
  display: flex;
  width: 100vw;
  min-height: 100vh;
  justify-content: center;
  align-items: center;
  transition: background-color 0.3s ease;
  padding: 20px;
}

body.correct { --hue: var(--hue-correct); }
body.wrong { --hue: var(--hue-wrong); }

.container {
  width: 800px;
  max-width: 90%;
  background-color: #ffffff;
  border-radius: 5px;
  padding: 20px;
  box-shadow: 0 10px 30px rgba(0,0,0,0.25);
}

.title {
  margin: 0 0 16px 0;
  font-size: 1.5rem;
  font-weight: bold;
  color: #2c3e50;
  text-align: center;
  letter-spacing: 0.5px;
}

.question {
  font-size: 1.6rem;
  font-weight: bold;
  color: #2c3e50;
  margin: 20px 0;
  text-align: center;
}

.btn-grid {
  display: grid;
  grid-template-columns: repeat(2, auto);
  gap: 10px;
  margin: 20px 0;
  justify-content: center;
}

.btn {
  --hue: var(--hue-neutral);
  background-color: hsl(var(--hue), 100%, 50%);
  border: 1px solid hsl(var(--hue), 100%, 30%);
  border-radius: 5px;
  padding: 10px 20px;
  color: white;
  outline: none;
  font-weight: bold;
  font-size: 1rem;
  cursor: pointer;
  transition: transform 0.15s ease, border-color 0.15s ease;
}

.btn:hover { border-color: black; }
.btn:active { transform: scale(0.98); }

.btn.correct {
  --hue: var(--hue-correct);
  color: white;
}

.btn.wrong {
  --hue: var(--hue-wrong);
  color: white;
}

.start-btn, .next-btn {
  font-size: 1.5rem;
  font-weight: bold;
  padding: 10px 20px;
}

.controls {
  display: flex;
  justify-content: center;
  margin-top: 20px;
}

.hide { display: none !important; }

@media (max-width: 500px) {
  .btn-grid { grid-template-columns: 1fr; }
  .question { font-size: 1.3rem; }
}