Microsoft Teams, the team communication app that Microsoft launched out of preview today, could be a better bet than Slack for certain groups for several reasons. For one thing, it integrates with Office 365.

But there’s one feature of Microsoft Teams that really gets me excited, one that shows that Microsoft cares about the little things. And little things are important if you’re going to live in an app.

Out of the box Microsoft Teams looks bright and cheery, with white and subdued light blue backgrounds. But you don’t have to stick with that. Because there is a dark theme. You can access it by tapping your avatar on the bottom left corner of the window, hovering over Themes, and clicking on Dark. Hurrah!

What you get is something much easier on the eyes — different shades of dark gray backgrounds, and chat messages are cast in gray or a blue-purple. It’s reminiscent of Twitter’s well-done dark theme.

Alternatively you can select Teams’ high-contrast theme. which puts light-colored boxes around different elements in the app and sets off certain text in white or yellow. I prefer the dark theme myself.

Slack, meanwhile, only lets you customize the theme of the sidebar. You can choose from a few options, or change the colors of different components within the sidebar. You cannot change the theme for the entire window. And Microsoft just exploited that limitation.

To be fair, there are some things about Slack that do seem better to me than what you find in Teams. Slack has a free tier even if you’re not an Office 365 customer, so you can use it for whatever you want without paying. And the chats have an informality about them that’s not quite there in Teams — everything feels more businesslike. Maybe that’s because there’s more space between chat messages in Teams.

But when it comes to being easier on the eyes, especially late at night, Teams, for today, owns Slack.

Update at 9:52 a.m. Pacific: The Android and iOS apps for Teams don’t support the dark theme, but Microsoft is working on it, a spokesperson told VentureBeat in an email.