:root{--primary-color:#42b983;--secondary-color:#f0f0f0;--correct-color:#28a745;--incorrect-color:#dc3545;--text-color:#2c3e50;--border-color:#e0e0e0}body{margin:0;font-family:Avenir,Helvetica,Arial,sans-serif;-webkit-font-smoothing:antialiased;-moz-osx-font-smoothing:grayscale;color:var(--text-color)}#app,.btn{text-align:center}.btn{display:inline-block;padding:.8rem 1.5rem;border:none;border-radius:8px;font-size:1rem;font-weight:500;cursor:pointer;transition:background-color .2s ease,transform .1s ease}.btn:hover{transform:translateY(-2px)}.btn-primary{background-color:var(--primary-color);color:#fff}.btn-secondary{background-color:var(--secondary-color);color:var(--text-color);border:1px solid var(--border-color)}.btn-correct{background-color:var(--correct-color);color:#fff}.btn-incorrect{background-color:var(--incorrect-color);color:#fff}.feedback-correct{color:var(--correct-color);font-weight:700}.feedback-incorrect{color:var(--incorrect-color);font-weight:700}