various fixes

layouts/shortcodes/button.html

@@ -0,0 +1,33 @@
+{{- /*
+    Renders a button, or no-JS fallback.
+
+    @params id  ID for button.
+    @params label   Label text for button.
+    @params text    Text for button.
+*/ -}}
+
+<!-- Validation -->
+
+{{- if ( not ( isset .Params "id" ) ) -}}
+    {{- errorf "No ID set for button (%q)" .Page.File.Path -}}
+{{- end -}}
+
+{{- if ( not ( isset .Params "label" ) ) -}}
+    {{- errorf "No label set for button '%q' (%q)" .Params.id .Page.File.Path -}}
+{{- end -}}
+
+{{- if ( not ( isset .Params "text" ) ) -}}
+    {{- errorf "No text set for button '%q' (%q)" .Params.id .Page.File.Path -}}
+{{- end -}}
+
+<!-- Rendering -->
+
+<noscript>You must have JavaScript enabled to interact with this button.</noscript>
+
+
+<label class="label label--button">
+    {{- .Params.label -}}:
+    <button id="{{- .Params.id -}}" class="button">
+        {{- .Params.text -}}
+    </button>
+</label>