RBA dark mode

I created this full stack multi-page app using Sveltekit and TailwindCSS. For the design, I tried to stay as close to eBird's own styling while adding a few UX features I would like to see incorporated such as grouping sightings by species/location and adding a dark mode. I incorporated some of the more modern eBird design elements such as boldly colored title and filter bars, filter tags as well as incorporating fades and slide-in animations for details and filter modals.