Merge mozilla-inbound to mozilla-central a=merge

devtools/client/themes/boxmodel.css

@@ -291,6 +291,7 @@
 .boxmodel-legend {
   position: absolute;
   z-index: 1;
+  cursor: default;
 }
 
 .boxmodel-legend[data-box="margin"] {
@@ -337,6 +338,7 @@
   border: 1px dashed transparent;
   -moz-user-select: none;
   white-space: nowrap;
+  cursor: pointer;
 }
 
 .boxmodel-editable[data-box="border"] {
@@ -349,6 +351,12 @@
   border-bottom-color: hsl(0, 0%, 50%);
 }
 
+.boxmodel-editable:focus,
+.boxmodel-editable:active {
+  border: 1px solid var(--blue-50);
+  outline: none;
+}
+
 .boxmodel-editable[data-box="margin"]:hover {
   background-color: var(--marginbox-border-color);
 }