How hard is it to write a wordpress theme to fit into an existing site?
WordPress is up and running on my host — but it completely mismatches my site’s existing theme/CSS. How hard would it be to modify/write a new theme to make it fit in? Is there an easier way to do this?
It might take some time to wrap your head around the theming system but it boils down to defining a stylesheet file for the theme and at least one PHP page template based on the master ‘look’ of your site. Add PHP code in strategic places to insert the title, posts, widgets, etc. and let WordPress do the heavy lifting. Look at other themes as examples, particularly the ones that claim to be simple and CSS-oriented, they should be easier to decipher.
Everything you need to know is here:
http://codex.wordpress.org/Theme_Development