<!DOCTYPE html> <title> Single-line column flex fragmentation: column balancing with forced break w/ vertical writing-mode. </title> <link rel="help" href="https://drafts.csswg.org/css-flexbox-1/#pagination"> <link rel="match" href="../../reference/ref-filled-green-100px-square.xht"> <style> #flex { display: flex; flex-direction: column; background: green; block-size: 100px; } #flex > div { inline-size: 25px; background: green; flex: none; } </style> <p>Test passes if there is a filled green square and <strong>no red</strong>.</p> <div style="writing-mode: vertical-rl;"> <div style="inline-size: 100px; block-size: 100px; background: red;"> <div style="inline-size: 100px; columns: 4; column-gap: 0; position: relative;"> <div id="flex"> <div style="block-size: 5px;"></div> <div style="block-size: 10px; break-before: column;"></div> <div style="block-size: 5px;"> <div style="block-size: 90px; inline-size: 25px; background: green;"></div> </div> <div style="block-size: 85px;"></div> <div style="block-size: 5px;"></div> <div style="block-size: 10px; break-before: column;"></div> <div style="block-size: 5px;"> <div style="block-size: 90px; inline-size: 25px; background: green;"></div> </div> </div> <div style="position: absolute; right: 5px; top: 50px; block-size: 95px; inline-size: 25px; background: green;"></div> </div> </div> </div>