Order summary text color change on checkout screen after Checkout Extensibility upgrade

Shopify Plus
,
1

Dear Shopify Community

I am currently trying to hide or change the text color of the Line Item Property in the Order Summary on a checkout page that has been upgraded to Shopify’s Checkout Extensibility, but have tried several methods without success.
Specifically, I would appreciate your advice on the following

Environment:.
We are using the Shopify Plus plan and have upgraded to Checkout Extensibility (only the checkout page has been upgraded).

Methods we have tried.

  1. edit the checkout.liquid file
    I edited the checkout.liquid file and added CSS styles, but they were not reflected as expected.
    CSS used:.
.order-summary__section--total .total-line-table .total-line__name,.
.order-summary__section--total .total-line-table .total-line__price,.
.order-summary__section--product .product-table .product__description {
color: #FF0000; /* desired text color */
}
  1. use of third-party apps
    I have installed apps such as Checkout Blocks and tried to customize it, but it was not reflected as expected.

Questions
On the Shopify Plus plan, are there any specific steps on how to hide the Line Item Property or change the text color in the order summary on the checkout screen?
Can you please advise on the correct way to change the Line Item Property hide or text color in customizing code edits such as liquid?
I would like to know if there are any other effective methods or applications.

Thank you in advance.