Use percentage for html root font size instead of px

[yvonnetangsu]

READY FOR REVIEW

Summary

• Use 62.5% for html font size instead of 10px, so people who set font size preferences in their browser can see elements scaling up.

Needed By (Date)

• Sooner the better

Urgency

• Not urgent

Steps to Test

1. Pull this branch and compile styleguide
2. Check that no rendered font sizes has changed compared to the live decanter site.

Affected Projects or Products

• Decanter

[yvonnetangsu]

I used Diffy to compare the live Decanter site to the tugboat URL. The only difference was caused by the addition of the local footer in the tugboat link. So I think we can safely make that change to the html based font size to use %.

[sherakama]

Thanks for checking!

[yvonnetangsu]

@sherakama , is it possible to also merge this into master?