Alternate row colors & add timestamp on check event

I’m using the CSS version of this to create a role (see below).

.anvil-role-striped > .anvil-data-row-panel:nth-child(even) {
    background:  %color:Gray 200%;
}

.anvil-role-striped > .repeating-panel > div > div:nth-child(even) {
  background: %color:Gray 200%;
}

Everything works great in the designer, but when I run the app, no alternating colors? What am I missing?