Show website layout

create bookmark with this location

javascript: (function() {
    const element = document.querySelector('#test-layout-styles');
    if (element) {
        document.head.removeChild(element);
    } else {
        const style = document.createElement('style');
        style.id = 'test-layout-styles';
        style.innerHTML = `
            * { background-color: rgba(255,0,0,.2); }
            * * { background-color: rgba(255,0,255,.2); }
            * * * { background-color: rgba(0,255,255,.2); }
            * * * * { background-color: rgba(255,255,0,.2); }
            * * * * * { background-color: rgba(0,255,0,.2); }
            * * * * * * { background-color: rgba(0,0,255,.2); }
            * * * * * * * { background-color: rgba(255,0,0,.2); }
            * * * * * * * * { background-color: rgba(255,255,0,.2); }
            * * * * * * * * * { background-color: rgba(0,255,255,.2); }
        `;
        document.head.appendChild(style);
    }
})();

source