I use a css class like so to target the modal-dialog class:
.app-modal-window .modal-dialog {
width: 500px;
}
Then in the controller calling the modal window, set the windowClass:
$scope.modalButtonClick = function () {
var modalInstance = $modal.open({
templateUrl: 'App/Views/modalView.html',
controller: 'modalController',
windowClass: 'app-modal-window'
});
modalInstance.result.then(
//close
function (result) {
var a = result;
},
//dismiss
function (result) {
var a = result;
});
};