border: none

[eGavr]

a {
    border:none;
}

is minimized to

a{border:0}

But border:0 is not always equivalent to border:none
While in simple case that would have the same effect, there could be differences when there are other border styles applied afterwards: http://dabblet.com/gist/8716224

[GoalSmashers]

Good catch 👍

[yisibl]

border: 0≠border: none≠border: 0 none