Choose which fonts to allow the browser to see/use, make it an array, filter the page's HTML, replace any fonts that don't match with Arial.
Beyond that you would probably want an extension that has functionality like RequestPolicy, so you could allow some sites access to "all fonts", or one could get even more finely grained down to which individual sites can use which font.
Although it could even be done at the OS level. It will be interesting to see who does it first. If the browser is truely caged and segregated, then it should only have indirect access to system level folders.
-webkit-box-sizing: border-box;
/* Safari/Chrome, other WebKit */
-moz-box-sizing: border-box;/* Firefox, other Gecko */
{
width:21px;
padding:5px;
margin:5px;
border: 1px solid black;
}
Where the total width is what you say it is: 21px. Instead we have the stupidity that the actual width is 32px. and paddings, margins et al ADD to the defined width instead of being a part of the element. Which makes calculating dimensions in HTML a fucking pain in the ass.
"Protozoa are small, and bacteria are small, but viruses are smaller than the both put together."