color: #000000; (Never specify color, unless you know what you're doing. This will be invisible in "night mode")
font-size: 100.00%; (Set the font size to the current font size, how smart)
font-style: normal;
font-variant: normal;
font-weight: normal; (No need to set "normal" in all of these, this should only be used for overriding other settings)
letter-spacing: 0.0000em; (It's so common to encounter some default letter-spacing...

)
margin-bottom: 0.0000%;
margin-top: 0.0000%; (What about margin-left and margin-right?)
padding-left: 0.0000%;
padding-right: 0.0000%; (What about padding-top and padding-bottom?)
text-align: left; (Great, now I can't set it justified in my reader)
text-decoration: none; (In case someone did set the default to underlined?)
text-indent: 3.0000%;
text-transform: none; (In case someone set the defaut to uppercase?)
Besides, all those decimals are just clutter, every "0.0000xx" can be replaced with a simple "0" (no units needed for 0).
Unlike JSWolf, my preferred <p> style is:
Code:
p {
margin: 0
text-indent: 1.2em /* no strong preference, anything between 1em and 2em */
}
The text-align, I leave it to the renderer, and I don't want extra separation between paragraphs.