src/ccDarkTheme/components/_query-builder.scss

// Filters (ec-query-builder)
material-condition-builder .compound-condition-operator {
  color: var(--TWPT-secondary-text)!important;
}

material-condition-builder .compound-condition-operator:is(::before, ::after) {
  border-left-color: rgba(255, 255, 255, .20)!important;
}

material-condition-builder .add-button,
    ec-query-builder .save-filter-button:not([disabled]) {
  color: var(--TWPT-blue-A100)!important;
}

material-condition-builder .add-condition,
    ec-query-builder .close-button {
  background-color: var(--TWPT-interop-blue)!important;
  color: #1f1f1f!important;
}