swa66 - 2:11 pm on Mar 25, 2013 (gmt 0)
To be honest, if you set a user stylesheet, it'll override *any* CSS (even inline) that a webmaster might have added. Now that works till you get to putting text in a box.
So IMHO, the lesson there is to "go with the flow" not try to change the base font size and measure other things on the page that need to be related in size to the fonts actually used in em instead of pixels. It might at first mean to do a little bit boring layout - but combine it with responsive design as suggested and it'll all work out.
Now any truly modern browser does zooming pretty well and that just makes everything bigger on the screen, including any graphic elements.
The more you use the above the better the zooming can work, but it'll work anyway.
One gotcha: if you use CSS sprites: leave a few pixels extra of background color around the elements: otherwise the background of a neighboring element might blend in due to the upscaling.
A high contrast alternate stylesheet is equally easy to make, and it would allow those who need it (not just cataract patients, the color blind often will find it a solution just as well) to go black&white only.
To do that, you do not need to offer any tool to change the stylesheet etc. All the visitor needs to do is select the stylesheet in his/her browser. E.g. in Firefox it's under View > Style demo page here:
To be honest the biggest thing holding us back isn't the webmaster side of things, it's the retarded browsers still out there that e.g. can't scale an image using a decent algorithm, that don't support all of CSS (including e.g. media queries), as well as 3rd party components such as ad networks and other stuff that are still in the middle ages when it comes to dynamically resizing things.
What I find wrong however is suing. If you can't use it: go elsewhere. But I guess it's an unfortunate aspect of the American way of living (which I do like except for a few things. One of them being that trigger happy nature when it comes to suing others).