body {
    font-family: Arial, sans-serif;
    line-height: 1.7;
    margin: 0;
    padding: 0;
    background-color: #ffffff;
    color: #1a1a1a;
}

header, footer {
    background-color: #f0f0f0;
    padding: 20px;
    text-align: center;
}

main {
    max-width: 800px;
    margin: 40px auto;
    padding: 0 20px;
}

h1, h2, h3 {
    color: #333333;
}

h1 {
    font-size: 2em;
    margin-bottom: 20px;
}

h2 {
    font-size: 1.5em;
    margin-top: 40px;
}

p {
    margin: 16px 0;
}

ul, ol {
    margin: 16px 0;
    padding-left: 20px;
}

li {
    margin-bottom: 10px;
}

a {
    color: #007acc;
    text-decoration: none;
}

a:hover {
    text-decoration: underline;
}

details {
    background-color: #f9f9f9;
    padding: 10px 15px;
    border: 1px solid #ddd;
    border-radius: 5px;
    margin: 10px 0;
}

summary {
    font-weight: bold;
    cursor: pointer;
}

img {
    max-width: 100%;
    height: auto;
    display: block;
    margin: 20px 0;
}

/* Accessibility: clear link focus */
a:focus {
    outline: 3px solid #ffa500;
    outline-offset: 2px;
}