body {
    font-family: sans-serif;
    margin: 0;
    display: flex;
    justify-content: center;
    align-items: center;
    min-height: 100vh;
    background-color: #f4f4f4;
}

.container {
    background-color: white;
    padding: 20px;
    border-radius: 8px;
    box-shadow: 0 2px 4px rgba(0, 0, 0, 0.1);
    width: 90%;
    max-width: 600px;
}

h1 {
    text-align: center;
    margin-bottom: 20px;
}

.input-section, .output-section, .decode-section, .decoded-output-section {
    margin-bottom: 15px;
}

label {
    display: block;
    margin-bottom: 5px;
    font-weight: bold;
}

textarea {
    width: 100%;
    padding: 10px;
    border: 1px solid #ccc;
    border-radius: 4px;
    resize: vertical; /* Cho phép thay đổi chiều cao */
    box-sizing: border-box;
}
button {
    padding: 10px 15px;
    background-color: #007bff;
    color: white;
    border: none;
    border-radius: 4px;
    cursor: pointer;
    margin-top: 5px;
    transition: background-color 0.3s;
}

button:hover {
    background-color: #0056b3;
}

button:active {
    transform: scale(0.98);
}