adding some more style

static/css/style.css

@@ -19,10 +19,9 @@ header {
   top: 0;
   width: 256px; 
   min-height: 100vh;
-  overflow-y: scroll;
-  -webkit-overflow-scrolling: touch;
+  overflow: hidden;
   background-color: #5763ab;
-  z-index: 0; 
+  z-index: 9999;
   display: none; 
   transition: transform 0.5s ease-out;
 }
@@ -187,6 +186,10 @@ footer {
 .side-menu.active {
   display: block;
 }
+body.side-menu.active {
+  overflow: none;
+}
+
 
 .content:before {
   content: '';
@@ -199,11 +202,14 @@ footer {
   width: 100%;
   background-color: rgba(0, 0, 0, 0.5);
   z-index: 99;
+  overflow: hidden;
 }
+
 .content-open{
   margin-left: -256px;
   transition: margin-left 0.1s;
   background-color: rgba(0, 0, 0, 0.5);
+  overflow: hidden;
 }
 
 .header-move{
@@ -211,3 +217,6 @@ footer {
   transition: margin-left 0.1s;
   background-color: rgba(55, 65, 105, 1.0);
 }
+.block-scroll{
+  overflow: hidden;
+}