Does CSS affect PageRank and search ranking?

[narutodude000]

I noticed that phpBB (a forum software) removes CSS if a bot is visiting the forums. But WordPress (a blog software) keeps the CSS.

I remember than font-weight:bold increases the value for a word. But should I use remove CSS if it's a bot (GoogleBot, etc)

[pixelsworld]

Google has no issue with CSS, because that contains the design code and Google doesn't check any design code. Google crawlers mainly check keywords and content quality.

[narutodude000]

But Google takes speed as a factor. If I load the CSS, my website will take longer to load. I already cloaked the Javascript because it's completely useless to search engines.

[Jarrod1937]

Don't cloak javascript, i wouldn't be surprised to see that google has been experimenting with analysing javascript to make sure dev's aren't presenting different content to the users than google bot.
You also shouldn't alter the css for googlebot specifically for the same reason. In fact google does do some css checks currently (making sure you aren't doing keyword stuffing with invisible text...etc).
In fact i'd say your entire approach is wrong. Google has included site speed as a rank factor because it wants the speed of the site to be good for the SITE USERS. You should thus actually try to increase the speed of your site for anyone who visits it, user or googlebot.