I just noticed this neat little tip over on MSD2D.
By Default all text boxes have fixed width of 386px. It’s common to wish to change this and here is how you can do it simply using CSS.
Note: This message is not part of the MSD2D article but … Remember editing “Default” files is never a good idea. This situation is slightly different as it is a lightweight edit but make sure you comment very well anything you change. This is better done via a theme.css in my personal opinion but that wouldn’t make it global.
Open OWS.CSS. It is located under C:\Program Files\Common Files\Microsoft Shared\web server extensions\60\TEMPLATE\LAYOUTS\1033\STYLES. (for non-english WSS and non-english site definitions, too, you should find and open corresponding OWS.CSS files).
Change width in ms-long class from 386px to 100%.
This class is used by ListFormWebPart for text fields (like Title) and multiline text fields (like Comment).
Add width: 100% to ms-formbody class.
This class is used by ListFormWebPart for
Result will be that all text boxes in New Item / Edit Item forms for all lists now will use full width of browser window and will dynamically resize as you resize the browser.
font-family: Verdana, sans-serif;