Lumo defines a set of CSS custom properties you can use to apply consistent visual styles across your application.
style.html to use them.
You can adjust the top level border radius, which affects many element themes directly.
If you want to set the border radius to zero, you need to specify a unit for it as well (i.e.
0em), as it can be used in
calc functions which will be undefined if
--lumo-border-radius is a unitless value.