body {
            font-family: Arial, sans-serif;
            background-color: #f4f4f4;
            display: flex;
            justify-content: center;
            align-items: center;
            height: 100vh;
            margin: 0;
        }
        .container {
            background-color: white;
            padding: 40px;
            border-radius: 8px;
            box-shadow: 0 0 10px rgba(0, 0, 0, 0.1);
            text-align: center;
            max-width: 400px;
            width: 100%;
        }
        h1 {
            color: #333;
            margin-bottom: 30px;
        }
        .login-options {
            display: flex;
            flex-direction: column;
            gap: 15px;
        }
        button {
            padding: 15px 20px;
            font-size: 16px;
            border: none;
            border-radius: 5px;
            cursor: pointer;
            transition: background-color 0.3s;
            color: white;
        }
        #trainer {
            background-color: #4CAF50;
        }
        #trainer:hover {
            background-color: #45a049;
        }
        #check_test {
            background-color: #2196F3;
        }
        #check_test:hover {
            background-color: #0b7dda;
        }
        #tests {
            background-color: #FF9800;
            color: black;
        }
        #tests:hover {
            background-color: #F57C00;
        }