Random color generation for all DOM elements so you can see where that pesky whitespace is coming from.

ES6 Version

m=Math.random,v=255;Array.from(document.querySelectorAll("*")).forEach(e=>{e.style.background=`rgb(${m()*v|0},${m()*v|0},${m()*v|0})`})

Mini Version

a=document.querySelectorAll('*'),m=Math.random,v=255,x=0;while(x<a.length){r=m()*v|0,g=m()*v|0,b=m()*v|0;a[x].style.background="rgb("+r+","+g+","+b+")";x++;}

Space Finder

var all = document.querySelectorAll('*');

for(var x = 0; x < all.length; x += 1){
    
    var thisThing = all[x];
    var r = Math.floor(Math.random()*255);
    var g = Math.floor(Math.random()*255);
    var b = Math.floor(Math.random()*255);

    thisThing.style.backgroundColor = "rgba(" + r + ", " + g + ", " + b + ", 1)";

}

Tweetable ES6 Version

m=Math.random,v=255;Array.from(document.querySelectorAll("*")).forEach(e=>{e['style'].background=`rgb(${m()*v|0},${m()*v|0},${m()*v|0})`})

Slightly more condensed ES6 version.

m=Math.random,v=255;for(e of Array.from(document.querySelectorAll('*'))){e.style.background=`rgb(${m()*v|0},${m()*v|0},${m()*v|0})`}