I'll be the first to admit that I still have some work to do regarding making my site more accessible. That being said, there's something that really pisses me off about people who talk about web accessibility on the internet, and that's that they always completely disregard the importance of dark modes and low-contrast themes.
There are a lot of extremely common conditions that make people's eyes more sensitive to bright light: migraines, tiredness, being in a dark room, and literally just having light colored eyes. High contrast is important for some, but for a lot of us, so is low contrast. You're designing a glowing screen, not a piece of paper, and you need to account for that.
There's one site I've seen linked a few times that makes me angry every time I open it. This person has an award for web accessibility, yet her site is genuinely painful to look at. Black text on bright white is literally as bad as it gets, and that's exactly what it is. There's not even a dark mode option. Firefox's Reader Mode doesn't work on some of the site's pages, so if you want to read it, you are forced to stare directly at a bright white screen and try to read as your eyeballs melt out of your head. I'm seriously considering emailing the webmaster. The information on the site is probably very useful, but it's all inaccessible to me.
This problem is easily solved by just offering a toggle with some basic JavaScript. My dark mode is designed with eyes like mine in mind, the light mode is based on feedback from other people, and the grayscale mode is made to be high contrast for those who are colorblind. It's not perfect, but it's way better than this for your entire page.
I understand that the vast majority of people who are making personal sites as opposed to commercial sites aren't going to be concerned about this at all anyway. I'm not going to sit here and say you're evil for making your personal website whatever colors you want. But please, for the love of god, don't go around touting your site as "accessible" without having options for both types of people, because people with visual impairments aren't a monolith and something that helps one person will hurt another.