How do you apply custom styles to a Popup Window in the Modern UI?

I would like to modify the styles for the popup window on the AR302000 page.

however, after multiple attempts, it doesn't seem to be taking effect. Is something wrong?

-AR302000

--extensions

---AR302000_CustomCss.html

---AR302000_CustomCss.css

--AR302000.html

--AR302000.ts

AR302000_CustomCss.html:

<template>

    <require from="./AR302000_CustomCss.css" />

</template>

AR302000_CustomCss.css:

#paymentDialog .qp-resizable {

  height: 85vh;

}

.aabbcc {

  height: 72vh;

}

.top-bar-cont{

  background-color: red;

}