I resolve partially in the forum of plugin (i must choose the css variable button). The button appears as the others but not centered.
Sorry for my knowledge in CSS
i try with this code a with a new class
.button-center {

margin: 0 auto;

display: table;

}
I have centered the writing “read more”(leggi) but i lost the button configuration as default.
how could i found the default css button setting in css in generate press to integrate the code?
thanks