body {
    font-family: Arial, sans-serif;
    background-color: #f0f0f5;
    margin: 0;
    padding: 0;
}

header {
    background-color: #ffffff;
    box-shadow: 5px 5px 15px rgba(0, 0, 0, 0.2);
    padding: 20px;
    text-align: center;
}

h1,h2 {
    color: #333;
}

main {
    display: flex;
    flex-direction: column;
    align-items: center;
    padding: 20px;
}

.introduction, .toprow-keys, .tips, .resources {
    background: #ffffff;
    border-radius: 15px;
    box-shadow: 5px 5px 15px rgba(0, 0, 0, 0.1);
    padding: 20px;
    margin: 15px 0;
    width: 90%;
    max-width: 600px;
}

ul {
    list-style-type: none;
    padding: 0;
}
.toprow-keys ul li {
    margin-bottom: 10px;
}
.tips ul li {
    list-style-type: disc;
    margin-bottom: 10px;
}

a {
    display: inline-block;
    padding: 10px 20px;
    background: #007BFF;
    color: #ffffff;
    border-radius: 25px;
    text-decoration: none;
    transition: background 0.3s;
}

a:hover {
    background: #0056b3;
}

footer {
    text-align: center;
    padding: 10px;
    margin-top: 20px;
    color: #777;
}