My div is not being fully 100% as there is still a margin to it

output:

[![enter image description here](https://i.stack.imgur.com/OkduY.png)](https://i.stack.imgur.com/OkduY.png)

at the top there is still some whitespace

**CSS code:**

```
.topbar {
    width: 100%;
    height: 10%;
    background-color: black;
}

```

thanks!