fix(frontend): make header checkin button full width

assets/css/build/public.css

@@ -961,6 +961,8 @@ strong, b {
 .but > .fa:not(.fa-angle-right),
 .but > i[class*="fa-"]:not(.fa-angle-right) { margin-right: 0.25em; }
 
+.but.block { display: block; }
+
 /* hover / active */
 .but:focus,
 .but:hover { opacity: 0.8; color: var(--this-color); }