Variable overrides

It seems to be recommended approach to override the variables in variables.scss vs putting !important in another css to override different items, however some are missing

for example i have a < p> and <h 2> inside my item but for ios there is $item-ios-paragraph-font-size however that same variable does not exist for android or windows so how does one override that?

second, i have h2 inside my item and there is no variable to override, there is $h2-font-size which has no effect on the item because some how this is showing up in source
source says its in man.css but not sure what variable is responsible for generating that

.item-md h2 { margin: 2px 0; font-size: 1.6rem; font-weight: normal; }
I have no idea where this is coming from

There seems to be a lot of variables missing depending on the platform, is this normal?
for example there is $list-md-header-min-height but there isnt one for android and windows, just seems all over the place so I am not sure what the right approach is here, i am just thinking override everything with !important in another css file but i was trying to make this as maitanable as possible