How to add css file for an html page?

I’ve created a new ‘Page’ doctype and attached the corresponding ‘HTML’ file in to xyzform.js file by using $(frappe.render_template("xyzform", page)).prependTo(page.main); command.

Now i want to add a corresponding css file to this html page. how can i add this ??

Does this mean its impossible to see changes to CSS file on live site without executing bench build command every time you make a change?