help with css

[Disa]

hello, i am new in this, how can i make css as the image, fixed width 700 px

[bluewalrus]

not really clear what you mean but maybe
#content {
width:700px;
}
That will make a div named content 700 pixels wide if you want a height you can use height:$xpx; where as $x will be a value to be the height.
If thats what you want don't know what you mean by image.

[Snookerman]

[...]don't know what you mean by image.
He/She means the attached image.

@Disa:
Here are the basics of what you want:

HTML code:
<div id="wrapper">
<div id="header">Header</div>
<div id="content">Content</div>
<div id="footer">Footer</div>
</div>
CSS code:
div div {
background-color:#eeeeee;
margin:5px;
border: 1px solid #999999;
}
#wrapper {
margin:auto;
width:700px;
text-align:center;
}
#header {
height:30px;
}
#content {
height:500px;
}
#footer {
height:30px;
}

Good luck!