How to remove the border around the ion-toggle

ionic-v1
1 
<ion-content  ng-init="checkarrivee.getAllListeCriteres();">
   <div class="swipe" on-swipe-left="warn('Must use scope')">Swipe div</div>
 <div class="list" style="width: 95%;margin-left: 2%">
 <span us-spinner="{color: 'blue', radius:30, width:8, length: 16}" spinner-key="spinner-0"></span>

   <label class="item item-input item-stacked-label">
   <span class="input-label">Mission en cours :</span>
    <input ion-autocomplete name="vehicule" type="text" readonly="readonly" class="ion-autocomplete"


       items-clicked-method="itemsClicked(callback)"
       items-removed-method="itemsRemoved(callback)"
       placeholder="Séléctionner une mission"
       items-method="getMissionEnCours(query)"
       external-model="initialCountry"
       item-view-value-key="codeDeFicheDeMission"

       items-method-value-key="items"
       max-selected-items="1"
       autocomplete="off"
       ng-model="checkarrivee.ficheDeMission"
       required/>
  </label>
 </div>
    <ion-list   ng-repeat="(key,value) in checkload | groupBy:'Niveau'">
<ion-item  on-swipe-left="warn('Must use scope')" ng-repeat="var in value" >


<ion-toggle ng-model='checkarrivee.boo[var.id]'  ng-click="checkarrivee.isMissionSelected(var.id,checkarrivee.ficheDeMission.id)" toggle-class="toggle-positive">{{var.designation}}</ion-toggle>
<button  class="button button-clear icon ion-star button-assertive"
        ng-click="toggleStar(var)" ng-show="var.star">
</button>
<ion-option-button class="button-dark" >
  <i class="icon ion-star"></i>
</ion-option-button>
![image](upload://oHievI07JWFDAvrdrMtOPcZ8FYe.png)