CSS Text properties not working in IE7 and Mozilla

I am having problems with font properties in my sidebar across different browsers.

This is my website:
https://habitswap.com/

In Google Chrome, the text looks how I want it to. Apparently in IE7 and Mozilla, the text is big black and none of the properties below seem to be working.

Below is my sidebar code in the CSS file:

/*sidebar*/
#sidebar {
width:289px;
float:left;
color: #grey;
font-size:75%;
font-family: arial, Helvetica, sans-serif;
line-height: 1.7em;
}

Thanks.