<!DOCTYPE html> <!-- Any copyright is dedicated to the Public Domain. - http://creativecommons.org/publicdomain/zero/1.0/ --> <html> <style> body { width: 400px; } div#float { float: left; width: 200px; height: 200px; background-color: lightgreen; } div#details { float: left; background-color: orange; } div#summary { background-color: green; } </style> <body> <div id="float"></div> <div id="details"> <div id="summary">Summary</div> <!-- No content due to closed details --> </div> </body> </html>