Borderless textfield in Vaadin 14

I am trying to practice the example from this video https://www.youtube.com/watch?v=qUBt8k4pQgQ from Vaadin 8 to Vaadin 14 but I don’t know how to replicate the borderless textfield. I tried to set the textfield to readonly and set the style border-style to none but it still has the dashed border.