--- a/devtools/client/themes/floating-scrollbars-dark-theme.css
+++ b/devtools/client/themes/floating-scrollbars-dark-theme.css
@@ -10,16 +10,17 @@
   -moz-appearance: none !important;
   position: relative;
   background-color: transparent;
   background-image: none;
   z-index: 2147483647;
   padding: 2px;
 }
 
+*|*:root[platform="mac"] > scrollbar,
 *|*:root[platform="mac"] *|*:not(html|select) > scrollbar {
   border: none;
 }
 
 /* Scrollbar code will reset the margin to the correct side depending on
    where layout actually puts the scrollbar */
 *|*:not(html|select) > scrollbar[orient="vertical"] {
   margin-left: -10px;
@@ -35,18 +36,23 @@
 
 *|*:not(html|select) > scrollbar thumb {
   background-color: rgba(170, 170, 170, .2) !important; /* --toolbar-tab-hover */
   -moz-appearance: none !important;
   border-width: 0px !important;
   border-radius: 3px !important;
 }
 
+*|*:root[platform="mac"] > scrollbar slider,
 *|*:root[platform="mac"] *|*:not(html|select) > scrollbar slider {
   -moz-appearance: none !important;
 }
 
+*|*:root[platform="win"] > scrollbar scrollbarbutton,
+*|*:root[platform="linux"] > scrollbar scrollbarbutton,
+*|*:root[platform="win"] > scrollbar gripper,
+*|*:root[platform="linux"] > scrollbar gripper,
 *|*:root[platform="win"] *|*:not(html|select) > scrollbar scrollbarbutton,
 *|*:root[platform="linux"] *|*:not(html|select) > scrollbar scrollbarbutton,
 *|*:root[platform="win"] *|*:not(html|select) > scrollbar gripper,
 *|*:root[platform="linux"] *|*:not(html|select) > scrollbar gripper {
   display: none;
 }