body {
    background-color: #444;
    color: #f1f1f1;
    }
.container-sm {
    max-width: 550px;
    }
.container-video {
    max-width: 550px;
    }
a.button {
    background-color: #ffffff;
    padding: 10px;
    border: none;
    border-radius: 5px;
    text-decoration: none;
    color: #dc3545;
    font-size: 18px;
    font-weight: bold;
    }