WMD Editor preview newline disppears when using CSS reset

I added WMD开发者_如何学C Editor as Stackoverflow does, but I have in my css,

* 
{
    margin: 0px;
    padding: 0px;
}

This makes newlines disappear, so there is no more space between lines.

is there anything i can do in css for wmd-preview?

---

p { margin:0px 0 10px 0; }

I did this, and it's fine now, hooray!!!!!!!!!!!!!!!!!!!!!!