Please tweak the forum CSS with a single change to add spacing to paragraphs

[Gavin Ray]

Currently, posts with more than one paragraph become 
increasingly-unreadable walls of text due to CSS styles that 
specify 0 margin/padding between them (why?)

With one small change, we can make much easier to read. Below is 
a before/after:

```css
.post-body p {
     margin: 10px;
}

```

![before-after-margin-change-img](https://cdn.discordapp.com/attachments/272822912036372480/1063855754550972476/image.png)