Hi, 
can you try this: 

<name field="description"  class="apply_dimension"/>

Create a css file (edit_dimension.css), and put the following code : 

.apply_dimension {
width: 40%;
height: 40% !important;
}
Then create xml file template.xml to declare your css file. Like this : 
<?xml version="1.0" encoding="utf-8"?>
<odoo>
    <data>
     <template id="assets_common" name="web assets" inherit_id="web.assets_common">
            <t t-call="web.less_helpers"/>
                <xpath expr="//link[last()]" position="after">
                    <link rel="stylesheet" type="text/css" href="PATH TO YOUR CSS FILE"/>
                </xpath>
        </template>
    </data>
</odoo>
Finally, Add the xml file to your Manifest. 
Try it and let me know if it works. 
Regards.