CSS Margin: 0 is not setting to 0

Question

I\'m a new comer to web designing. I created my web page layout using CSS and HTML as below. The problem is even though i set the margin to 0, the upper margin is not settin

Answer 1

It seems that nobody actually read your question and looked at your source code. Here's the answer you all have been waiting for:

#header_content p {
    margin-top: 0;
}

jsFiddle