body {
            background-color: #1a1a1a;
            color: #ffffff;
        }
        .converter-container {
            max-width: 600px;
            margin: 0 auto;
            padding: 20px;
        }
        .header {
            background-color: #2d2d2d;
            padding: 2rem 0;
            margin-bottom: 2rem;
            border-bottom: 1px solid #404040;
        }
        .form-control {
            background-color: #2d2d2d;
            border-color: #404040;
            color: #ffffff;
        }
        .form-control:focus {
            background-color: #2d2d2d;
            border-color: #dc3545;
            color: #ffffff;
            box-shadow: 0 0 0 0.25rem rgba(220, 53, 69, 0.25);
        }
        .btn-danger {
            background-color: #dc3545;
            border-color: #dc3545;
        }
        .btn-danger:hover {
            background-color: #bb2d3b;
            border-color: #b02a37;
        }
        .alert-success {
            background-color: #2d6a4f;
            border-color: #40916c;
            color: #ffffff;
        }
        .alert-danger {
            background-color: #641220;
            border-color: #dc3545;
            color: #ffffff;
        }
        .btn-success {
            background-color: #2d6a4f;
            border-color: #40916c;
        }
        .btn-success:hover {
            background-color: #245c3f;
            border-color: #347d5a;
        }
        footer {
            background-color: #2d2d2d;
            border-top: 1px solid #404040;
        }

        .bold {
            font-weight: bold;
        }

        #youtube_url::placeholder {
            color: gray;
        }