Collapsed visualize play button taking full width

[jbudz]

[thomasneirynck]

The stretching of the buttons is due to a media query being applied when the mode changing from wide-screen to mobile version.

Not sure what the buttons "should" look like in the mobile version. That said though, we might want the buttons to stretch to full width, it gives it more of that "smart-phone" feel.

Note that the fix for #7808 fixes this issue, if we want the buttons to have the "stretch" behavior.

However, there is a larger issue with the CSS. The nav.navbar class, which forces a height of 70px to align the header with the Kibana logo, seems applied too liberally. Any (sub)component that applies it, is stretched to at least 70px. This includes the visualization headers. We should move that rule so it only applies to the header on top of the page, not all headers of all (sub)components.

[thomasneirynck]

example of header of visualization-form being too big.

[thomasneirynck]

For now, we want to retain the button expansion behavior, since it works a little better for small screen mobile layouts.

The overlap is due to a CSS issue that was addressed in #7850.