add css

govuk-internal-dq/login/resources/css/govuk-internal-dq.css

@@ -0,0 +1,29 @@
+@charset "UTF-8";
+/* GOV.UK customisations to implement beta internal header pattern (see https://home-office-digital-patterns.herokuapp.com/header) */
+@media (min-width: 769px) {
+  #global-header .header-wrapper .header-global .header-logo {
+    width: auto; } }
+
+.lte-ie8 #global-header .header-wrapper .header-global .header-logo {
+  width: auto; }
+
+/* Imitate #global-header #logo img (including the space after it!) from GOV.UK template, so that theme users don’t have to include the actual <img> tag in Display Name HTML when customising their header link */
+#logo::before {
+  content: '';
+  display: inline-block;
+  width: 36px;
+  height: 32px;
+  margin: 2px 1px 0 0;
+  vertical-align: bottom;
+  background: url("../vendor/govuk_template/images/gov.uk_logotype_crown_invert_trans.png?0.19.2") no-repeat;
+  visibility: hidden; }
+
+#logo:before {
+  content: '';
+  display: inline-block;
+  width: 36px;
+  height: 32px;
+  margin: 2px 1px 0 0;
+  vertical-align: bottom;
+  background: url("../vendor/govuk_template/images/gov.uk_logotype_crown_invert_trans.png?0.19.2") no-repeat;
+  visibility: hidden; }

govuk-internal-dq/login/theme.properties

@@ -1,2 +1,2 @@
 parent=govuk
-styles=css/govuk-internal.css
+styles=css/govuk-internal-dq.css