body {
    font-family: Arial, sans-serif;
    display: flex;
    justify-content: center;
    align-items: center;
    height: 100vh;
    margin: 0;
}
button.buttoncouleur {
    padding: 14px 20px;
    margin: 8px 0;
    border: none;
    cursor: pointer;
    width: 50%;
    font-size: 1.2em;
    text-align: center;
    border-radius:2em;
}
button.buttonmodeplen {
    padding: 14px 20px;
    font-size: 0.8em;
    border: none;
    text-align: center;
    border-radius: 2.5em;
    background-color: #007bff;
    color: white;
    position: absolute;
    top: 10px;
    right: 10px;
    padding: 10px 15px;
    font-size: 1em;
    border-radius: 10px;
}