body {
    font-family: 'Arial', sans-serif;
    background-color: #f9f9f9;
    color: #333;
    margin: 0;
    padding: 20px;
}

h1 {
    text-align: center;
    color: #333;
    margin-bottom: 40px;
}

.levels {
    display: flex;
    flex-direction: column;
    align-items: center;
}

.level-link {
    margin: 10px 0;
    padding: 12px 20px;
    border: 1px solid #ddd;
    text-decoration: none;
    color: #333;
    background-color: #fff;
    width: 50%;
    text-align: left;
    border-radius: 5px;
    box-shadow: 0 2px 5px rgba(0, 0, 0, 0.1);
    transition: background-color 0.3s, border-color 0.3s, box-shadow 0.3s;
}

.level-link:hover {
    background-color: #f1f1f1;
    border-color: #ccc;
    box-shadow: 0 4px 10px rgba(0, 0, 0, 0.15);
}

.footer {
    margin-top: 40px;
    text-align: center;
    color: #999;
}

.footer a {
    color: #666;
    text-decoration: none;
    border-bottom: 1px dotted #666;
    transition: color 0.3s, border-bottom-color 0.3s;
}

.footer a:hover {
    color: #333;
    border-bottom-color: #333;
}

.navbar-brand img {
    width: 26px;
    height: 26px;
}

.navbar .btn img {
    width: 24px;
    height: 24px;
    vertical-align: sub;
}