Why does filled input have rounded top corners but square bottom corners?

[ivanjaros]

and how can I make them all rounded or all square? I do not see scss variables that configure this.

[yusufkandemir]

It is following the Material Design definition. So, it's not configurable through props or SCSS variables.
https://m2.material.io/components/text-fields#anatomy

Rounded corners
The container of an outlined text field has rounded corners, while the container of a filled text field has rounded top corners and square bottom corners.

You can use CSS to globally override the styles or give a class to the input fields you want to override.

[ivanjaros]

thanks, i've used the css override. i hope that one day, quasar will finally cut its hard dependency on material design already.