CSS to get text right in different browsers and across ASP.NET site

General information for the business: I have 3 issues I want fixed.
Description of requirements/functionality: I have 3 issues I want fixed.

Have a look at http://www.urefilltoner.co.uk/


1) If you look at it in Safari or Chrome the paragraph text is the size I want. But I want a bit more space between lines to make it easier on the eye


2) If you look at it in IE9, the text appears smaller. And I want it to look the same size as in Safari + Chrome (+ the line height adjust)


3) Everything has to apply site-wide to support the brand.
But it is an ASP.NET site which uses themes and master
pages as well as (mainly) stand-alone CCS definition
files. There could be some awkward interplay between
themes etc. Which I didn't really get to the bottom of
when I wrote the site (and don't have time now). So if we got, say, the homepage looking right, we don't then want the new setup to throw out the presentation of the product detail pages (although if it improved them, that would be OK)
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