Keeping text aligned with background image

Hi guys,
I have a background image loaded, and have it positioned in the center.
I also have text and links over it that I would like to keep in the same spot on the background image, no matter how the window is resized.
Is this possible? I am aware that it can be done in CSS, yet I am not sure how to approach this using Harlowe's style sheet. :/

Here is my code:
html {
background-color:rgb(0, 0, 0);
background-image: url("https://...");
background-size:40%;
background-repeat:no-repeat;
background-position: center center;
background-attachment: fixed;
}
tw-passage
{
font-size: 22px;
position: fixed;
bottom:25%;
right:50%;
}

Thank you!