diff --git a/addons/website/static/src/scss/website.scss b/addons/website/static/src/scss/website.scss
index 906a0a6b15c..282317ecac6 100644
--- a/addons/website/static/src/scss/website.scss
+++ b/addons/website/static/src/scss/website.scss
@@ -637,7 +637,6 @@ $-transition-duration: 200ms;
     display: block;
     @include o-position-absolute(0, 0, auto, 0);
     position: fixed;
-    z-index: $zindex-modal - 20;
     background: $light;
 
     &:not(.o_header_no_transition) {
@@ -703,6 +702,10 @@ $-transition-duration: 200ms;
 
 // Header templates
 header {
+    &#top {
+        // We need this z-index for the shadow option of the header
+        z-index: $zindex-modal - 20;
+    }
     &:not(.o_header_no_transition) {
         .navbar-brand {
             transition: font-size $-transition-duration, opacity $-transition-duration ease-out;
diff --git a/addons/website/static/src/snippets/s_popup/000.scss b/addons/website/static/src/snippets/s_popup/000.scss
index b548a97dd79..02738156859 100644
--- a/addons/website/static/src/snippets/s_popup/000.scss
+++ b/addons/website/static/src/snippets/s_popup/000.scss
@@ -68,7 +68,7 @@
             }
         }
         .s_popup_content {
-            z-index: 1;
+            z-index: $zindex-modal;
             position: fixed;
             right: 20px;
         }