I'm redesigning my site because looks awful on different resolutions (apart devices), most guides and tutorials rely on % and em than fixed values. I'm still learning this so I'm reading everything around.
Thought this would solve the question with different display sizes but again: we have to craft some more CSS for fix some specific issues.
If I need to add media-queries for extra display sizes, why use % then? Do use % really reduce coding? Is ok need to add some extra css for some sizes or am I doing something wrong?
Thanks for any advice!
The purpose of using em sizes is to allow the base your design off of the user's choice of font size. I may use a larger font size because I have a huge monitor and poor eye sight, while someone else might prefer a smaller font. By using em units, your design will accommodate both of our font preferences and resize accordingly instead of forcing the font size to a given standard (eg. "12 point font").
In a similar manner, percent (%) units allow your design to respond to different browser sizes. Used in conjunction with em units, this will allow text-based elements to respond to arbitrary font size choices, and layout elements to respond to arbitrary browser sizes.
It is perfectly acceptable to design a single responsive design for all media types. Media queries are intended when you want different display styles on different devices, not to "support" different display sizes. An example would be to use serif fonts on print media and sans-serif fonts on display media, since usabilities studies have shown that these font faces are preferred for these sorts of media.
Furthermore, it allows you to do custom styling for some situations like mobile devices, where you may want to consider that the user has a limited amount of bandwidth and maybe cut down on extra images. Or if you want to display your content in a completely different layout for the microscopic screen afforded by certain phones.