window.onload = function() {
    (function() {
        var HTML = document.getElementsByTagName('head')[0];
        var colors = [
            '#ffe4da',
            '#ed2839',
            '#00ff7f',
            '#ffb6c1',
            '#02fcfa',
            '#fee834'
        ];
        var colorsCount = colors.length;
        var selectedColor = Math.floor((Math.random() * colorsCount) + 1) - 1;
        HTML.innerHTML += `
            <style>
                * {
                    background-color: ${colors[selectedColor]};
                    border-color: ${colors[selectedColor]} !important;
                }
            </style>
        `;
    })();
}