We found out that we can center it with the following codes:
.global-styles, [class*="RootLayout__RootComponent-sc"] {
margin: 0 auto;
}
or
.global-styles, [class*="RootLayout__Component-sc"] {
justify-content: center!important;
display: flex!important;
max-width: unset!important;
}
However, having settings for it in the widget editor would be nice. Thanks!