You can turn 'px' to 'em' or 'rem' units Instantly. The default base is 16px but you can define a custom base for each conversion
1 - Type cmd+shift+E on the line to be converted.
1 - Add the base value to the end of line. Example:
margin: 18px; /12
2 - Type cmd+shift+E and the result is:
margin: 1.5em; /* 18/12 */
*Both methods accept multiline conversion
Good catch. Let us know what about this package looks wrong to you, and we'll investigate right away.