What is the correct way to specify margin and padding in CSS?

Question

Are these valid values for margin and padding in CSS?

margin: 0px 10px;
padding: 5px 0px 10px;

I thought that you always had to specify all four sides:

margin: 0px 10px 0px 0px;
padding: 5px 0px 10px 0px;

Also, when I write CSS like margin: 0px 10px 0px 0px; my editor IntelliJ warns me that the px is redundant. Should properties like this be written differently?

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For anyone reading this post, the answer lies in all of the responses. Each clarifies the shorthand aspect. Thanks to all who responded.

Answer 1

You can specify fewer than 4 as a 'short-hand', which sets several properties to the same value at the same time; for example, the CSS documentation says:

body { margin: 2em }         /* all margins set to 2em */
body { margin: 1em 2em }     /* top & bottom = 1em, right & left = 2em */
body { margin: 1em 2em 3em } /* top=1em, right=2em, bottom=3em, left=2em */

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The dimension (e.g. px) is redundant when (only when) the value is 0.