100vw causing horizontal overflow, but only if more than one?

Question

Say you have this:

html, body {margin: 0; padding: 0}
.box {width: 100vw; height: 100vh}

Screen 1

You

Answer 1

to get rid of the scrollbar width included in vw i had to do this:

html, body {
    overflow-x: hidden;
    height: 100vh;
}