Ok now their are some bugs still present that i need some help quashing.
The first is spacing issues with certain tab link buttons and text blocks.
I created a video outlining specifically what i need help on Spacing issues video link – EDIT: managed to fix this one more or less.
For you text issues it seems like you aren’t using the EM unit properly / you are expecting it to behave differently then it is designed.
The em unity is relative to it’s parent font value not relative to screen size. Most people with set the base font size on the body element. Usually set to 1em which is typically the equivalent of 16px. This will be your body text.
Then you would set your heading sizes an example could be h1= 2.827em, h2= 1.999em, h3= 1.414em
This will give a nice even scale down to each heading.
Once that is all done you can switch to a new view port say the tablet view. All you have to do now is lower the base size on the body to say 0.707em. This will proportionally change all other text sizes at the same time.