Misc cleanup

frontend/src/metabase/components/List.css

@@ -84,13 +84,13 @@
 }
 
 :local(.itemSubtitle) {
-    color: color(var(--subtitle-color) shade(20%));
-    font-size: 16px;
+    color: var(--subtitle-color);
+    font-size: 14px;
 }
 
 :local(.itemSubtitleLight) {
     color: var(--subtitle-color);
-    font-size: 16px;
+    font-size: 14px;
 }
 
 :local(.itemSubtitleBold) {

frontend/src/metabase/reference/Reference.css

@@ -14,8 +14,7 @@
 }
 
 :local(.guideEmptyMessage) {
-    composes: text-dark mt3 from "style";
-    text-align: left;
+    composes: text-dark text-centered mt3 from "style";
     font-size: 1.1em;
     line-height: 1.457em;
 }

frontend/src/metabase/reference/selectors.js

@@ -23,7 +23,7 @@ const referenceSections = {
             adminMessage: "Defining common metrics for your team makes it even easier to ask questions",
             message: "Metrics will appear here once your admins have created some",
             image: "/app/img/metrics-list",
-            adminAction: "Create a metric",
+            adminAction: "Learn how to create metrics",
             adminLink: "http://www.metabase.com/docs/latest/administration-guide/05-segments-and-metrics.html"
         },
         breadcrumb: "Metrics",
@@ -40,7 +40,7 @@ const referenceSections = {
             adminMessage: "Defining common segments for your team makes it even easier to ask questions",
             message: "Segments will appear here once your admins have created some",
             image: "/app/img/segments-list",
-            adminAction: "Create a segment",
+            adminAction: "Learn how to create segments",
             adminLink: "http://www.metabase.com/docs/latest/administration-guide/05-segments-and-metrics.html"
         },
         breadcrumb: "Segments",