css - Questions on using the 'rem' unit, advice needed -

happy friday everyone, i've got project allows me quite bit of freedom far trying new things , setting modern design standards @ corporate level. i've not spent time in past experimenting 'rems', think (mobile) project perfect time tinker around in real-world scenario. support low ie8, , know fonts fixed using this mixin, problem solved.

what hear community's experience using 'rems' structure , positioning. wise use 'rems' everything? best used widths , heights? using margins , paddings?

this more of fact-finding mission coming guys specific problem, please feel free reply and/or advice!

thanks! :)

if comfortable em, using rems should fine, long can live reduced browser support, or willing add fallbacks.

i use rem everything, except in horizontal dimensions, might want use percentage values.

i more or less map rem value pixels, setting root element’s (html) font-size 62.5%. 10px if user hasn’t changed browser default. rem maps font-size of root element, mapping between px rem divide 10. benefit of pixels, such font size being predictable , easy work out, benefit of ems in values scale , down when changing text size (including if user needs set larger base font size due reduced vision or motor skills). except better em need change html font size scale. in mind, may not want set values in rem if want them stay constant size when other elements scale.

i can’t think of i’d recommend not set in rems.