fix #2860: truncate .dl-horizontal terms and reset to stacked for <767px layouts

less/responsive-767px-max.less

@@ -86,6 +86,21 @@
     padding: 0;
   }
 
+  // TYPOGRAPHY
+  // ----------
+  // Reset horizontal dl
+  .dl-horizontal {
+    dt {
+      float: none;
+      clear: none;
+      width: auto;
+      text-align: left;
+    }
+    dd {
+      margin-left: 0;
+    }
+  }
+
   // GRID & CONTAINERS
   // -----------------
   // Remove width from containers

less/type.less

@@ -135,6 +135,7 @@ dd {
 // Horizontal layout (like forms)
 .dl-horizontal {
   dt {
+    .text-overflow();
     float: left;
     clear: left;
     width: 120px;