Themes are about accessibility first, personalization second

Mark Miro
2 min readJul 14, 2022

Although custom themes and variations are often responsible for broken UI states like the one below, developers love themes. Why? Developers aren’t known for their vanity about how things look.

Hues stand out better against a dark background than a light one. In light mode, blue and black look almost the same. In dark mode, blue and white are easier to distinguish.

Programmers spend a lot of time behind screens and they know what they like. The downside of a dark theme is that you’re more sensitive to external light hurting the legibility of the text on your screen. Dark UIs can look really bad on glossy screens experiencing glare. But glossy screens are also sharper and show color better. I worked at a few companies that had too much light getting into the office from the windows. These windows were often boarded up.

I couldn’t find a picture of a startup with boarded up windows. Usually, “boarded-up” is associated with a business closing, and that’s what Google gave me.

I tend to like my light themes, but this is because I like sunlight more than I like colored syntax, though I often go back and forth. And it’s also because I tend to turn up my screen brightness as high as possible to compensate for the external light. It’s also why I bought a MacBook Pro with a 1000 nit display and installed Vivid so I could make use of it.

The other reason I lean toward light mode is that it can be hard to adjust my eyes to a web page with a dark background after I’ve been staring at code in a dark-themed editor while coding into into the evening. This is why I’m tempted to use a light theme even at night.

Darkness also messes with my circadian rhythm. It’s easy for me to fall into a pattern of falling asleep later every night unless I’m careful with my screen time at night and the amount of sunlight I get during the day.

Themes serve a real practical purpose. Seeing them as tools for personalization serves to unfairly diminish the importance of what a theme can do.