body {
            box-sizing: border-box;
        }
        .sentence-card {
            transition: all 0.3s ease;
        }
        .sentence-card:hover {
            transform: translateY(-2px);
            box-shadow: 0 8px 25px rgba(0,0,0,0.15);
        }
        .copy-btn {
            transition: all 0.2s ease;
        }
        .copy-btn:hover {
            transform: scale(1.05);
        }