<!DOCTYPE html> <!-- Any copyright is dedicated to the Public Domain. http://creativecommons.org/publicdomain/zero/1.0/ --> <html> <head> <title>CSS Test: Testing a horizontal flex container with box-sizing:border-box</title> <link rel="author" title="Daniel Holbert" href="mailto:dholbert@mozilla.com"> <meta charset="utf-8"> <style> .container { display: flex; width: 110px; height: 30px; border: 5px solid black; box-sizing: border-box; } .itemA { flex: 1 28px; background: purple; border: 1px solid indigo; } .itemB { flex: 1 48px; background: teal; border: 1px solid lightblue; } </style> </head> <body> <div class="container"> <div class="itemA"></div> <div class="itemB"></div> </div> </body> </html>