How do you change your chromebook screen negative?

Making a screen negative can help the strain on eyes. To do so create a bookmark using this code JavaScript: (function(){ vary newSS, styles='* { background: white ! important; color: black !important } :link, :link * { color: #0000EE !important } :visited, :visited * { color: #551A8B !important }'; if(document.createStyleSheet) { document.createStyleSheet("JavaScript:'"+styles+"'"); } else { newSS=document.createElement('link'); newSS.rel='style sheet'; newSS.href='data:text/css,'+escape(styles); document.getElementsByTagName("head")[0].appendChild(newSS); } } )();