Delayed explore query loading indicator and implemented minor ux improvements to it

public/sass/pages/_explore.scss

@@ -118,11 +118,6 @@
     overflow: hidden;
     background: none;
     margin: $panel-margin / 2;
-    transition: background-color 1s ease;
-  }
-
-  .explore-panel__loader--active {
-    background: $text-color-faint;
   }
 
   .explore-panel__loader--active:after {
@@ -133,16 +128,19 @@
     top: -50%;
     height: 250%;
     position: absolute;
-    animation: loader 2s cubic-bezier(0.17, 0.67, 0.83, 0.67);
+    animation: loader 2s cubic-bezier(0.17, 0.67, 0.83, 0.67) 500ms;
     animation-iteration-count: 100;
+    left: -25%;
     background: $blue;
   }
 
   @keyframes loader {
     from {
       left: -25%;
+      opacity: .1;
     }
     to {
+      opacity: 1;
       left: 100%;
     }
   }