made hover work

shop/templates/layout.html

@@ -29,10 +29,13 @@
 
 <div id="page-container">
 
-    <div class = "header">
-        <img class = "header_img" onmouseover="{{ url_for('static', filename='images/dark_logo_orange.png') }'" onmouseout="{{ url_for('static', filename='images/dark_logo.png') }}" src = "{{ url_for('static', filename='images/dark_logo.png') }}" alt="logo image"/>
-    </div>
-
+    <div class="header">
+  <img class="header_img"
+       src="{{ url_for('static', filename='images/dark_logo.png') }}"
+       onmouseover="this.src='{{ url_for('static', filename='images/dark_logo_orange.png') }}'"
+       onmouseout="this.src='{{ url_for('static', filename='images/dark_logo.png') }}'"
+       alt="logo image" />
+</div>
     <ul class = "navbar">
         <li><div class = "navbar_box_home"><a class = "navbar_item" href="{{ url_for('home') }}">Home</a></div></li>
         <li><div class = "navbar_box_home"><a class = "navbar_item" href="{{ url_for('shopping') }}">Shopping</a></div></li>