React Spacing - Bootstrap 4 & Material Design. Examples & tutorial - Material Design for Bootstrap より

Screen Size Class
Appears on all .ml-3
Appears only on xs .ml-3 .ml-sm-0
Appears only on sm .ml-sm-3 .ml-md-0
Appears only on md .ml-md-3 .ml-lg-0
Appears only on lg .ml-lg-3 .d-xl-0
Appears only on xl .ml-xl-3