diff --git a/addons/mail/static/src/components/drop_zone/drop_zone.scss b/addons/mail/static/src/components/drop_zone/drop_zone.scss
index 119da547560..ba9939e84f4 100644
--- a/addons/mail/static/src/components/drop_zone/drop_zone.scss
+++ b/addons/mail/static/src/components/drop_zone/drop_zone.scss
@@ -1,27 +1,8 @@
-// ------------------------------------------------------------------
-// Layout
-// ------------------------------------------------------------------
-
-.o_DropZone {
-    display: flex;
-    position: absolute;
-    top: 0;
-    left: 0;
-    height: map-get($sizes, 100);
-    width: map-get($sizes, 100);
-    z-index: 1;
-    align-items: center;
-    justify-content: center;
-}
-
-// ------------------------------------------------------------------
-// Style
-// ------------------------------------------------------------------
-
 .o_DropZone {
     color: $o-enterprise-primary-color;
     background: rgba(255, 255, 255, 0.9);
     border: 2px dashed $o-enterprise-primary-color;
+    z-index: 1;
 
     &.o-dragging-inside {
         border-width: 5px;
diff --git a/addons/mail/static/src/components/drop_zone/drop_zone.xml b/addons/mail/static/src/components/drop_zone/drop_zone.xml
index b2e00bf0bef..a721805480c 100644
--- a/addons/mail/static/src/components/drop_zone/drop_zone.xml
+++ b/addons/mail/static/src/components/drop_zone/drop_zone.xml
@@ -2,7 +2,7 @@
 <templates xml:space="preserve">
 
     <t t-name="mail.DropZone" owl="1">
-        <div class="o_DropZone" t-att-class="{ 'o-dragging-inside': state.isDraggingInside }" t-attf-class="{{ className }}" t-on-dragenter="_onDragenter" t-on-dragleave="_onDragleave" t-on-dragover="_onDragover" t-on-drop="_onDrop" t-ref="root">
+        <div class="o_DropZone position-absolute top-0 start-0 align-items-center justify-content-center d-flex w-100 h-100" t-att-class="{ 'o-dragging-inside': state.isDraggingInside }" t-attf-class="{{ className }}" t-on-dragenter="_onDragenter" t-on-dragleave="_onDragleave" t-on-dragover="_onDragover" t-on-drop="_onDrop" t-ref="root">
             <h4>
                 Drag Files Here <i class="fa fa-download"/>
             </h4>