<!DOCTYPE html> <html> <head> <style type="text/css"> .float-left, .float-right { float: left; width: 125px; height: 1em; background-color: red; } .float-right { float: right; } fieldset { margin: 0; padding: 0; border: none; height: 5em; background-color: green; } #plus-margin { margin: 0 100px 0; } </style> </head> <body> <div class="float-left"></div> <div class="float-right"></div> <fieldset></fieldset> <div class="float-left"></div> <div class="float-right"></div> <fieldset id="plus-margin"></fieldset> </body> </html>