Add styles and animations for onboarding helper

- Add styles for popover
- Add $accepting-mr-label-color to color variables

app/assets/stylesheets/components/popover.scss

@@ -39,6 +39,25 @@
   }
 }
 
+.onboarding-popover {
+  box-shadow: 0 2px 4px $dropdown-shadow-color;
+
+  .popover-body {
+    font-size: $gl-font-size;
+    line-height: $gl-line-height;
+    padding: $gl-padding;
+  }
+
+  .popover-header {
+    display: none;
+  }
+
+  .accept-mr-label {
+    background-color: $accepting-mr-label-color;
+    color: $white-light;
+  }
+}
+
 .onboarding-welcome-page {
   .popover {
     min-width: auto;

app/assets/stylesheets/framework/animations.scss

@@ -268,3 +268,27 @@ $skeleton-line-widths: (
   @include webkit-prefix(animation-duration, 1s);
   transform-origin: 50% 50%;
 }
+
+/* ----------------------------------------------
+ * Generated by Animista on 2019-4-26 17:40:41
+ * w: http://animista.net, t: @cssanimista
+ * ---------------------------------------------- */
+@keyframes slide-in-fwd-bottom {
+  0% {
+    transform: translateZ(-1400px) translateY(800px);
+    opacity: 0;
+  }
+
+  100% {
+    transform: translateZ(0) translateY(0);
+    opacity: 1;
+  }
+}
+
+.slide-in-fwd-bottom-enter-active {
+  animation: slide-in-fwd-bottom 0.4s cubic-bezier(0.25, 0.46, 0.45, 0.94) both;
+}
+
+.slide-in-fwd-bottom-leave-active {
+  animation: slide-in-fwd-bottom 0.4s cubic-bezier(0.25, 0.46, 0.45, 0.94) both reverse;
+}

app/assets/stylesheets/framework/common.scss

@@ -501,3 +501,38 @@ img.emoji {
     }
   }
 }
+
+.onboarding-helper-container {
+  bottom: 40px;
+  right: 40px;
+  font-size: $gl-font-size-small;
+  background: $gray-100;
+  width: 200px;
+  border-radius: 24px;
+  box-shadow: 0 2px 4px $issue-boards-card-shadow;
+  z-index: 10000;
+
+  .collapsible {
+    max-height: 0;
+    transition: max-height 0.5s cubic-bezier(0, 1, 0, 1);
+  }
+
+  &.expanded {
+    border-bottom-right-radius: $border-radius-default;
+    border-bottom-left-radius: $border-radius-default;
+
+    .collapsible {
+      max-height: 1000px;
+      transition: max-height 1s ease-in-out;
+    }
+  }
+
+  .avatar {
+    border-color: darken($gray-normal, 10%);
+
+    img {
+      width: 32px;
+      height: 32px;
+    }
+  }
+}

app/assets/stylesheets/framework/variables.scss

@@ -641,6 +641,7 @@ $input-lg-width: 320px;
 */
 $document-index-color: #888;
 $help-shortcut-header-color: #333;
+$accepting-mr-label-color: #69d100;
 
 /*
 * Issues