How to remove top border from Blogspot?

Step 1:

On your Dashboard, select Layout. This will take you to the Template tab. Click Edit HTML. Under the Edit Template section you will see you blog's HTML.



Step 2:
Look for tags #header-wrapper

#header-wrapper {
width:660px;
margin:0 auto 10px;
border:0px solid $bordercolor;
}

Just Copy this code anywhere...
#navbar-iframe {
height:0px;
visibility:hidden;
display:none
}

done!