[IMP] add orderlist-screen css class to limit selectors

pos_order_mgmt/static/src/css/pos.css

@@ -1,4 +1,5 @@
 /* Copyright 2018 Tecnativa - David Vidal
+   Copyright 2019 Druidoo - Iván Todorovich
    License LGPL-3.0 or later (https://www.gnu.org/licenses/lgpl).
 */
 
@@ -6,7 +7,7 @@
     font-size: 20px;
 }
 
-.order-line .button {
+.orderlist-screen .order-line .button {
     cursor: pointer;
     top: 0px;
     line-height: 32px;
@@ -19,13 +20,13 @@
     transition: all 150ms linear;
 }
 
-.order-line .button:active {
+.orderlist-screen .order-line .button:active {
     background: black;
     border-color: black;
     color: white;
 }
 
-.order-returned-warning {
+.orderlist-screen .order-returned-warning {
     font-size: 16px;
     font-style: italic;
     padding: 8px 0;

pos_order_mgmt/static/src/xml/pos.xml

@@ -10,7 +10,7 @@
     </t>
 
     <t t-name="OrderListScreenWidget">
-        <div class="clientlist-screen screen">
+        <div class="orderlist-screen clientlist-screen screen">
             <div class="screen-content">
                 <section class="top-content">
                     <span class='button back'>