Add example tooltips

styles/atat.scss

@@ -16,6 +16,7 @@
 @import 'elements/action_group';
 @import 'elements/labels';
 @import 'elements/diff';
+@import 'elements/tooltip';
 
 @import 'components/topbar';
 @import 'components/global_layout';

styles/elements/_tooltip.scss

@@ -0,0 +1,109 @@
+.tooltip {
+  display: block;
+  z-index: 10000;
+
+  .tooltip-inner {
+    background: $color-black;
+    color: $color-white;
+    border-radius: $border-radius;
+    padding: 5px 10px 4px;
+  }
+
+  .tooltip-arrow {
+    width: 0;
+    height: 0;
+    border-style: solid;
+    position: absolute;
+    margin: 5px;
+    border-color: black;
+    z-index: 1;
+  }
+
+  &[x-placement^="top"] {
+    margin-bottom: 5px;
+
+    .tooltip-arrow {
+      border-width: 5px 5px 0 5px;
+      border-left-color: transparent;
+      border-right-color: transparent;
+      border-bottom-color: transparent;
+      bottom: -5px;
+      left: calc(50% - 5px);
+      margin-top: 0;
+      margin-bottom: 0;
+    }
+  }
+
+  &[x-placement^="bottom"] {
+    margin-top: 5px;
+
+    .tooltip-arrow {
+      border-width: 0 5px 5px 5px;
+      border-left-color: transparent;
+      border-right-color: transparent;
+      border-top-color: transparent;
+      top: -5px;
+      left: calc(50% - 5px);
+      margin-top: 0;
+      margin-bottom: 0;
+    }
+  }
+
+  &[x-placement^="right"] {
+    margin-left: 5px;
+
+    .tooltip-arrow {
+      border-width: 5px 5px 5px 0;
+      border-left-color: transparent;
+      border-top-color: transparent;
+      border-bottom-color: transparent;
+      left: -5px;
+      top: calc(50% - 5px);
+      margin-left: 0;
+      margin-right: 0;
+    }
+  }
+
+  &[x-placement^="left"] {
+    margin-right: 5px;
+
+    .tooltip-arrow {
+      border-width: 5px 0 5px 5px;
+      border-top-color: transparent;
+      border-right-color: transparent;
+      border-bottom-color: transparent;
+      right: -5px;
+      top: calc(50% - 5px);
+      margin-left: 0;
+      margin-right: 0;
+    }
+  }
+
+  &.popover {
+    $color: #f9f9f9;
+
+    .popover-inner {
+      background: $color;
+      color: black;
+      padding: 24px;
+      border-radius: 5px;
+      box-shadow: 0 5px 30px rgba(black, .1);
+    }
+
+    .popover-arrow {
+      border-color: $color;
+    }
+  }
+
+  &[aria-hidden='true'] {
+    visibility: hidden;
+    opacity: 0;
+    transition: opacity .15s, visibility .15s;
+  }
+
+  &[aria-hidden='false'] {
+    visibility: visible;
+    opacity: 1;
+    transition: opacity .15s;
+  }
+}