Why Percentage-Based Designs Don't Work in Every Browser. Here’s a rule any web designer can live by: Your designs don’t need to look exactly the same in every browser, they just need to look good in every browser.
It’s a maxim that will spare you many a hair-pulling hour. That said, there some things you would expect to be the same across browsers that aren’t. One such problem that’s likely to crop up more often as designers jump on the responsive, flexible-width bandwagon is percentage-width CSS rules. Two HTML Standards Diverge in a Wood. The two standards bodies that are jointly responsible for developing the HTML specification have cut the final tie that was binding them together. The World Wide Web Consortium (W3C) and the Web Hypertext Application Technology Working Group (WHATWG) began to move apart last year when the WHATWG announced it would drop the version number and work on a “living standard” sans version numbers.
The W3C continued to focus on HTML “snapshots” like HTML5. However, despite that split the two shared an editor, Ian Hickson, who oversees both specs. Or did. Tim Berners-Lee on the next Web.