Fix heights on transitions, text/plain display in dark mode

src-ui/src/app/components/common/page-header/page-header.component.scss

@@ -0,0 +1,9 @@
+.h2 {
+    min-height: calc(1.325rem + 0.9vw);
+}
+
+@media (min-width: 1200px) {
+    .h2 {
+        min-height: 2.8rem;
+    }
+}