body {
            font-family: Arial, sans-serif;
            background-color: #121212;
            color: #ffffff;
            margin: 0;
            padding: 0;
            display: flex;
            flex-direction: column;
            align-items: center;
        }
        header {
            background-color: rgba(31, 31, 31, 0.9);
            width: 100%;
            padding: 20px 0;
            background-image: url('BloodImage.png');
            background-repeat: no-repeat;
            background-position: center center;
            text-align: center;
            border-bottom: 2px solid #333;
        }
        .container {
            width: 90%;
            max-width: 1200px;
            margin: 20px auto;
            display: flex;
            flex-wrap: wrap;
            justify-content: space-around;
        }
        .card {
            background-color: rgba(31, 31, 31, 0.9);
            width: 300px;
            margin: 10px;
            padding: 20px;
            border-radius: 10px;
            box-shadow: 0 0 10px rgba(0, 0, 0, 0.5);
            transition: transform 0.2s;
            cursor: pointer;
            position: relative;
        }
        .card:hover {
            transform: scale(1.05);
        }
        .card h2 {
            margin-top: 0;
        }
        .facile{

            background-color: #1a852c;

        }
        .moyen{

            background-color: #857e1a;

        }
        .difficile{

            background-color: #85261a;

        }
        .difficulty{
            position: absolute;
            top: 10px;
            right: 10px;
            color: white;
            padding: 5px 10px;
            border-radius: 5px;
            font-weight: bold;
        }
        .modal {
            display: none;
            position: fixed;
            z-index: 1;
            left: 0;
            top: 0;
            width: 100%;
            height: 100%;
            overflow: auto;
            background-color: rgba(0, 0, 0, 0.8);
        }
        .modal-content {
            background-color: #1f1f1f;
            margin: 15% auto;
            padding: 20px;
            border: 1px solid #888;
            width: 80%;
            max-width: 600px;
            border-radius: 10px;
            box-shadow: 0 0 10px rgba(0, 0, 0, 0.5);
        }
        .close {
            color: #aaa;
            float: right;
            font-size: 28px;
            font-weight: bold;
        }
        .close:hover,
        .close:focus {
            color: #fff;
            text-decoration: none;
            cursor: pointer;
        }