.sentence-box {
            background: white;
            padding: 20px;
            border-radius: 12px;
            max-width: 80%;
            display: flex;
            align-items: center;
            justify-content: center;
            text-align: center;
            border: 5px solid #333333;
            transition: border-color 0.5s ease;
        }

        .sentence {
            font-size: medium;
            line-height: 1.2;
            color: #333;
            opacity: 1;
            transition: opacity 0.5s ease;
        }

        .sentence.fade-out {
            opacity: 0;
        }