body {
    background-image: url("data:image/svg+xml;utf8,
    <svg xmlns='http://www.w3.org/2000/svg' width='100%' height='100%'>
        <defs>
            <pattern id='grid' width='80' height='80' patternUnits='userSpaceOnUse'>
                <path d='M 80 0 L 0 0 0 80' fill='none' stroke='#b69658' stroke-width='1'/>
            </pattern>
        </defs>
        <rect width='100%' height='100%' fill='url(#grid)'/>
    </svg>");
    background-attachment: fixed;
    background-size: cover;
}