CRM2013 - what is the best way to create HTML web resource which will look very similar to existing fields on the form?

CRM2013 - what is the best way to create HTML web resource which will look very similar to existing fields on the form?

When screen size is changed, web resource controls should also resize along with existing field.

Controls in HTML web resource should look similar to existing fields (style: width,font etc)

Thanks

Krish