# Understanding Overriding ionic variables

#1

hi , perhaps this is a silly question but I am a bit confused.

what the difference between `\$tabs-background` and `\$tabs-md-background`?
does that mean if I use the second one or maybe the first one , it will apply for both Android and IOS ?

and also some of them come with `md` and `ios`… for example, `\$tabs-ios-tab-icon-color-active`
but there is no `\$tabs-tab-icon-color-active` .

I guess what I am trying to understand, which one applies for both of the platforms… Do I have to use both `md` and `ios` in order to get it working for both platforms ?