I have a website that constantly gets bigger and bigger as a user uses it. It is not yet complete, although I believe it is time for a better UI. So, how do I make it so the user feels more welcome. Currently it's a blue and orange, with round buttons and text boxes, but I was thinking of making changing it to make the textboxes and buttons rectangular with thick, neon-light-blue borders and a black background, somewhat similar to the Zorin OS linux distrobution. Is it smart to use a darker theme with a dynamic page, or should I keep it the same?
A dark theme will make your page stand out, whether in a good way or not is down to the specific implementation, but most pages default to a light theme.
The current blue-orange palette is very high contrast and might be jarring for users, especially given the subject matter. Compared to other language based sites (eg, Dictionary.com), which generally consist of a light theme focusing on a single accent color, your site stands out.
Using a dark theme may not be a bad idea overall if it suits the aesthetic you want for the site, but moving away from two colors would help calm the site down at least.
The current version was bit difficult for me as a user to follow. Maybe if you created cards (like decks of material design) that are placed next to each other, it would be easier to follow through. Also, keeping a light theme is definitely the preferred choice. It will be less stressful to the eyes and is found to have higher engagement than a dark theme such as the one you currently have.