body {
    font-family: Arial, sans-serif;
    margin: 0;
    padding: 0;
}

header {
    background-color: #f8f8f8;
    padding: 20px;
    text-align: center;
    border-bottom: 1px solid #ddd;
}

header h1 {
    margin: 0;
    font-size: 24px;
}

nav ul {
    list-style-type: none;
    padding: 0;
}

nav ul li {
    display: inline;
    margin: 0 10px;
}

nav ul li a,
nav ul li button {
    text-decoration: none;
    color: blue;
    font-weight: bold;
}

nav ul li button {
    background: none;
    border: none;
    cursor: pointer;
    padding: 0;
}

main {
    padding: 20px;
    text-align: center;
}

h2 {
    font-size: 20px;
    margin-bottom: 20px;
}

form {
    margin-bottom: 20px;
}

#scoreChart,
#resultChart {
    display: block;
    margin: 20px auto;
}