<!DOCTYPE html> <html> <head> <meta charset="utf-8"> <title>Minimum height on fieldset</title> <style> div { writing-mode: vertical-lr; } fieldset { background:rgba(0,0,0,0.1); border-color:teal; border-width:2px; height:200px; } </style> </head> <body> <div> <fieldset> <p>Lorem ipsum.</p> </fieldset> </div> </body> </html>