.wrapper { width:100%; max-width:990px; <<<<<<<<<<<<<<<<<< Change this line to the line below max-width:90%; margin:0 auto; position:relative}
#footer { text-align:left; background:#333; color:#ebebec; padding:40px; <<<<<<<<<<<<<<<<<< Remove this line, add the two lines below padding-top:40px; padding-bottom:40px; font-size:12px; overflow-x:hidden; overflow-y:hidden; box-shadow:0 0 5px rgba(0,0,0,.15)}
What about this: https://www.lateral.io/resources-blog/create-chrome-extension-modify-websites-html-css
adjusting the template server-side would be beneficial for everybody