Add styles for channel highlights (fixes #121)

scss/modules/flexpane/_channel.scss

@@ -149,3 +149,90 @@
     border-color: $color-red !important;
   }
 }
+
+.c-channel_insights__title {
+  color: $base-font-color;
+}
+
+.c-channel_insights__section:not(.c-channel_insights__section--no_border) {
+  border-color: $color-shade-light;
+}
+
+.c-channel_insights__drawer_title {
+  color: $color-highlight;
+}
+
+.c-channel_insights__item--user {
+  .member_preview_link,
+  .message_sender {
+    color: $base-font-color !important;
+  }
+}
+
+.c-channel_insights__user_title {
+  color: $color-highlight;
+}
+
+.c-channel_insights__channel {
+  .channel_link {
+    color: $base-font-color;
+  }
+}
+
+.c-channel_insights__member_count {
+  color: $color-highlight;
+
+  .ts_icon_user {
+    color: $color-highlight;
+  }
+}
+
+.c-channel_insights {
+  .c-member__title {
+    color: $color-highlight;
+  }
+}
+
+.c-channel_insights__activity {
+  border-color: $color-shade-light;
+}
+
+.c-channel_insights_activity_bar_container {
+  &:hover {
+    background-color: rgba($color-shade-darkest, 0.05);
+
+    .c-channel_insights__activity_bar {
+      background-color: $color-shade-light;
+    }
+  }
+}
+
+.c-channel_insights__activity_bar {
+  background-color: rgba($color-shade-light, 0.5);
+}
+
+.c-channel_insights__message ts-message.standalone:not(.for_mention_display):not(.for_search_display):not(.for_top_results_search_display):not(.for_star_display) {
+  background-color: $color-base;
+  border-color: $color-shade-light;
+}
+
+.c-channel_insights__message--truncate {
+  &::before {
+    background: linear-gradient(180deg, transparent, $color-base 90%);
+  }
+}
+
+.c-channel_insights__highlights_description {
+  color: $color-highlight;
+}
+
+.c-channel_insights__date_heading {
+  span {
+    background-color: $color-base;
+    color: $base-font-color;
+  }
+
+  &::before {
+    background-color: $color-shade-light;
+  }
+}