Fix dark mode in front nav

Author: jvns

assets/sass/dark-mode.css

@@ -112,10 +112,6 @@
                 @include box-shadow(none);
             }
 
-            #front-nav img {
-                filter: none;
-            }
-
             div.monitor {
                 filter: brightness(.85);
             }

assets/sass/front-page.scss

@@ -42,12 +42,17 @@
       grid-column: 1;
       transition-duration: 0.3s;
       transition-property: opacity;
-      opacity: 0.5;
+      opacity: 0.4;
       width: 38px;
       height: 38px;
       background-color: #cdcdc5;
       border-radius: 40%;
       padding: 18px;
+
+      :root[data-theme="dark"] & {
+        filter: invert(1);
+        background-color: #9d9c9a;
+      }
     }
 
     h3 {