This is a guide for organize header widgets into 3 column, this concept could be extended to 4-5 column with automated configuration (A idea for custom theme).
The options are many but I suggest to leave it as I wrote below:
@media screen and (min-width: 980px) {
/* c = $c = 3, 3 colonne */
[data-widgetArea='header'] > ul > li{
float: left;
display: inline-block !important;
padding: 0 !important;
margin: 0 1% 2% !important; /* m = 1 */
width: 32%; /*(100-(c*2-2)*m)/c =