How to Eliminate Post Date

Eliminate the bloggers posting date, would know how? The first entry Edit HTML page and then search h2.date-header (if already met add visibility: hidden; between the code. see the example code below:

<meta equiv="Content-Type" content="text/html; charset=utf-8">

h2.date-header {
margin:.3em 0 0;
padding:0;
font-size:80%;
color:#777;
height: 0px;
visibility: hidden;
}

GOOD LUCK - OYE