body { font-family: 'Inter', sans-serif; }
.fraction {
    display: inline-flex;
    flex-direction: column;
    vertical-align: middle;
    margin: 0 0.2em;
    text-align: center;
}
.fraction-sm {
    display: inline-flex;
    flex-direction: column;
    vertical-align: middle;
    margin: 0 0.1em;
    text-align: center;
    transform: scale(0.8);
}
.numerator {
    padding: 0 0.3em;
    border-bottom: 2px solid currentColor;
}
.denominator {
    padding: 0 0.3em;
}
.screen { display: none; }
.screen.active { display: block; }
.option-btn.correct { background-color: #22c55e; }
.option-btn.incorrect { background-color: #ef4444; }