Why does the distance of DIV change when the border is removed_html/css_WEB-ITnose

I added a headerDIV block to the container. This block has a border, and the distance from the edge of the container is exactly according to the margin value I set. However, as soon as I remove the border of the header, the header block will disappear. There is a certain distance from the upper border of the container. I don’t know why. Please give me some advice!

#container{	width:820px; height:100%;	border:1px solid #b58505;	margin:0px auto;}.top{	width:100%; height:52px; font-size:18px;	text-align:right; line-height:40px;	padding-right:20px; margin-left:-10px; margin-top:-10px;	background:url(../images/top.gif) repeat-x;}.top a:hover{ color:red; text-decoration:underline;}.top #srh{ 	vertical-align:top; margin-top:10px;	width:150px; height:18px; border:1px solid gray;}#header{	width:812px; height:303px;	border:1px solid gray;	margin:2px auto 0px;	background:url(../images/header_bg.png) no-repeat center;}

Reply to discussion (solution)

This should be the same without borders and empty spaces , if it is different, it only differs by the thickness of the border

Is it because you can’t see where the boundary is when you remove the border, so you think it is too empty?

There are many problems. I won’t go into detail. Except for the outermost layer, add a float:left; display:inline; to both the .top and #header layers. Try

Post pictures of the two effects. Look at

. There are many problems. I won’t go into details. Except for the outermost layer, add float:left; display:inline; to both .top and #header layers. Try
and it can be solved. But why is this? Woolen cloth?