How to change column width in wordpress css

Hi

I am using a div with css to insert 2 columns into wordpress posts but I wondered if there was a way for me to define a width for each column.

many thanks

.content {
-moz-column-count: 3;
-moz-column-gap: 10px;
-moz-column-rule: none;
-webkit-column-count: 3;
-webkit-column-gap: 10px;
-webkit-column-rule: none;
column-count: 3;
column-gap: 10px;
column-rule: none;
}