still wrong minus about lessphp HOT 1 CLOSED

margin: 26 - 50px 290 - 190px;

Will return you the expected result ;)

space are required,

because the parser can make the diff betwenn - and a hyphen (like in display : inline-block; )

in any case, use () for a better presentation

margin: (26 - 50px);
margin: (26 - 50px) (209 - 109px); 

but if you use (), use it every time because

margin: 26 - 50px 209 - 109px -5px;  

will work as

margin: (26 - 50px) (209 - 109px) (-5px);  /* margin:-24px 100px -5px; */

BUT mixed will not work

margin: (26 - 50px) (209 - 109px) -5px;    /* margin:-24px 95px; */

from lessphp.