made watermark disappear together w/ the YTM logo

BetterYTM.user.js

@@ -347,6 +347,7 @@ function addWatermark()
 
     const style = `\
     #betterytm-watermark {
+        display: inline-block;
         position: absolute;
         left: 45px;
         top: 43px;
@@ -356,6 +357,12 @@ function addWatermark()
         cursor: pointer;
     }
 
+    @media(max-width: 615px) {
+        #betterytm-watermark {
+            display: none;
+        }
+    }
+
     #betterytm-watermark:hover {
         text-decoration: underline;
     }`;