fix: button style margin set zero globally

[Djunnni]

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• If this is a code change: I have written unit tests and/or added dogfooding pages to fully verify the new behavior.
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Motivation

in safari, button element default margin left and right set 2px;

but Chrome and firefox were not set 2px;

so i check how to use in facebook.

they are using static style sheet by cdn
(https://static.xx.fbcdn.net/rsrc.php/v3/yC/l/0,cross/xv165oDvQLn.css?_nc_x=Ij3Wp8lg5Kz)

in there set

button {
 margin: 0
}

if we set this, we can remove css that some of button set margin: 0

i set default value in theme/Layout/styles.module.css but i think it's not best.
could you advice about that?

Related issues/PRs

none

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[slorber]

Thanks

Unfortunately changing such global styling is likely to affect some users so I'd rather avoid doing this as a casual bug fix but rather as a general overhaul of the CSS reset we use in Infima, and including this in a well-documented major release of Docusaurus.

The good place to do that is here: https://github.com/facebookincubator/infima/blob/main/packages/core/styles/common/base.pcss

See also useful tools:

• http://necolas.github.io/normalize.css/
• https://meyerweb.com/eric/tools/css/reset/
• https://www.joshwcomeau.com/css/custom-css-reset/

For Docusaurus, I'm not against an immediate fix but only for our own theme buttons, on a case-by-case basis, ie apply this locally with className instead of using a global element rule.