Edit in JSFiddle

var app = angular.module("tabPanel",[]);
app.controller("tabPanelCtrl",function($scope){
    $scope.tabSelected = "#tab1";
    $scope.tabChange = function(e){
        if (e.target.nodeName === 'A') {
            $scope.tabSelected = e.target.getAttribute("href");
            e.preventDefault();
        }
    }
})

<div  ng-app="tabPanel" ng-controller="tabPanelCtrl" ng-click="tabChange($event)">
<a href="#tab1" ng-class="{'active':tabSelected=='#tab1'}">tab1</a>
<a href="#tab2" ng-class="{'active':tabSelected=='#tab2'}">tab2</a>
<a href="#tab3" ng-class="{'active':tabSelected=='#tab3'}">tab3</a>
<div id="tab1" class="ng-hide" ng-show="tabSelected=='#tab1'">CSS1</div>
<div id="tab2" class="ng-hide" ng-show="tabSelected=='#tab2'">CSS2</div>
<div id="tab3" class="ng-hide" ng-show="tabSelected=='#tab3'">CSS3</div>
</div>

a.active{
    font-weight:bold;
}