I run into the cause of this issue quite a bit when writing styling. The fact is that each major browser veers from the spec in its own unique ways, so if you'r

I run into the cause of this issue quite a bit when writing styling. The fact is that each major browser veers from the spec in its own unique ways, so if you're testing your page in a single browser (usually Chrome, though personally I use FF) the styling will often end up working differently in other browsers. As of now, the only real solution is to pick a set of "supported browsers" and to test your page in each of them before publishing, tweaking your styles to work around each engine's quirks. The problem with a browser monoculture is that it encourages developers to only test against the dominant platform, forcing competitors to be bug-compatible in order to provide a non-broken experience. The advantage is that a true and reliable standard would emerge, making developers' lives easier. Of course, the optimal solution would be for browsers to properly conform to the existing standards so that testing across browsers wouldn't be necessary in the first place, as any deviations would be a bug that would hopefully be fixed before too long.