<!DOCTYPE HTML> <!-- Any copyright is dedicated to the Public Domain. http://creativecommons.org/publicdomain/zero/1.0/ --> <html><head> <title>Reference: dynamic change .left on abs.pos. item w. align-self:center</title> <link rel="author" title="Mats Palmgren" href="https://bugzilla.mozilla.org/show_bug.cgi?id=1405319"> <style type="text/css"> html,body { color:black; background-color:white; font:16px/1 monospace; padding:0; margin:0; } .grid { display: inline-grid; position: relative; background: lightgrey; grid: 50px 50px / 50px 50px; } #item { background: grey; position: absolute; align-self: center; left: 20px; } </style> </head> <body> <div class="grid"> <div id="item">X</div> </div> </body> </html>