padding of text when using vw font-size

I am using vw to make a text enlarge according to the browser the page is open in. However, the padding is bigger than expected. I want it to be exactly in the top corner of my page with little to no padding. (I tried padding:0px; with no result). Here's an example:

In HTML:

<heading>some text</heading>

In CSS:

heading{
  font-size:5vw;
  padding:0px;
  margin:0px;
}