Changing tab width on tab panel

I'm writing an app in Sencha-touch. I have 3 tabs in a tab panel. I'd like each one to take up 33% of the width of the tab panel. I've tried using resizeTabs, tabWidth, and even added a class to each item and then referenced it in css to change the width.

Then I also tried using a span element in the html and referencing that. But none of it works. My code is below. How do I change the width of the tabs in a tab panel?

{
    xtype: 'tabpanel',
    fullscreen: true,
    tabBarPosition: 'top',
    resizeTabs: true,
    tabWidth: '33%',
    items:[
           {
               //title: 'Campus List',
               html: '<span class="headerTab">Campus List</span>',
               width: '33%',
               cls: 'headerTab'
           },
           {
               title: 'Meter List',
               html: 'Meter List',
               width: '33%',
               cls: 'headerTab'  
           },
           {
               title: 'Meter',
               html: 'Meter',
               width: '33%',
               cls: 'headerTab'  
           }
    ]

}

I figured it out. If you reference the xtype of the tab, not the tabpanel, in your css then it will resize the tabs. Here's what worked.

.x-tab{
    width: 33%;
}