body {
    font-family: system-ui, -apple-system, sans-serif;
    margin: 0;
    padding: 0;
    line-height: 1.5;
    color: #333;
    background: #fff;
    max-width: 800px;
    margin: auto;
    padding: 1rem;
}

header nav {
    text-align: right;
}

button {
    background: none;
    border: none;
    cursor: pointer;
    font-weight: bold;
}

h1, h2 {
    color: #000;
}

ul, ol {
    padding-left: 1rem;
}

form {
    display: flex;
    flex-direction: column;
}

input, button {
    margin-bottom: 0.5rem;
}

@media (max-width: 600px) {
    body {
        padding: 0.5rem;
    }
}

/* Accessibility: High contrast */
a, button:focus {
    outline: 2px solid #000;
}