CSS positioning problem..help? | Yahoo Answers

hi..

i have been learning html/css from 2 days....and i am stuck now

my html codding--------

<!DOCTYPE html>

<html>

<head>

<link type="text/css" rel="stylesheet" href="stylesheet.css"/>

<title></title>

</head>

<body>

<div id="header"></div>

<div class="right"></div>

<div class="left"></div>

<div id="footer"></div>

</body>

</html>

and css file linked with it-------------

#headerborder:2px solid blue;height:50px;margin:0px 0px 20px 0px;

.left{border:2px solid blue;height:500px;width:200px;float:left...

.right{border:2px solid blue;height:500px;float:right;width:450p...

#footerborder:2px solid blue;height:100px;clear:both;

---------------------------------------...

the results in smal sceen r as in pic....but when i c this on full screen .......then gap btwn the two vertical boxes increases( i mean the left hand side box sticks to left and right box sticks to right side & therefore gap in btwn increases) .........

i want the gap between boxes the same as u can see in attached pic....even when i maximizes the window....

https://answers.yahoo.com/question/index?qid=20150620085533AAuENU2