Lower signature line is fucky, don't know why I didn't notice.

More vertical padding around the show list items, bit cramped inside and outside the selection box

That red is unreadable and the vertical tallness of the font makes it read like a headliney sentence, not a list. Aligning it right looks nice but also confuses its function since you start expecting it to be tied/labelling the show list, but it's standalone. Better colour and left/center alignment would clarify that

Little more differentiation between Watching and Completed would be more visually and emotionally satisfying, as well as clearer at a glance, such as slightly greying the show names that are completed or simply pushing it farther down the page a bit

Also the header for Watching/Completed is a little too visually similar for the show lists, they're v different typefaces but they're both bold, black, and a similar size. Try making the show list lighter

And align that red list vertically with the div holding the Watching/Completed, or however you organized that. It looks weird floating in space

Good idea tho, anime fans are very proud and goal-oriented about watching their anime compared to netflix addicts etc, and most streaming sites/apps are ugly and annoying