When changing the text field background color it seems to be fully opaque, however you have a grayscale filter applied on the background video element that is causing it’s children (in this case, the vibrant gold text field) to appear washed out:
In terms of getting the text field to respond more appropriately, one change that may help out is setting the background video element to
display: flex which would allow for easier alignment of its children elements. I’d also recommend adjusting the text content to remove the additional spaces between each line, and instead set the line-height to 1- which will prevent each line from overlapping the next.
Do you have reference imagery for what you’re wanting it to look like?