(This article was first published on Yihui Xie, and kindly contributed to R-bloggers)
R's default theme of the HTML help pages is too plain for me to read, but we can easily modify the theme, which is essentially a CSS file. You can find the file under:
file.path(R.home('doc'), 'html', 'R.css')
Simply replace this file with my version of R.css (1K) which looks like:

Of course you can design your own R.css if you know CSS.
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