Fix alignment of sign in/sign up button

app/assets/stylesheets/framework/common.scss

@@ -305,14 +305,6 @@ img.emoji {
   margin-bottom: 10px;
 }
 
-.btn-sign-in {
-  text-shadow: none;
-
-  @include media-breakpoint-up(sm) {
-    margin-top: 8px;
-  }
-}
-
 .side-filters {
   fieldset {
     margin-bottom: 15px;

app/assets/stylesheets/framework/header.scss

@@ -447,12 +447,16 @@
 .btn-sign-in {
   background-color: $indigo-100;
   color: $indigo-900;
-  margin-top: 3px;
   font-weight: $gl-font-weight-bold;
+  line-height: 18px;
 
   &:hover {
     background-color: $white-light;
   }
+
+  @include media-breakpoint-down(xs) {
+    margin-top: $gl-padding-4;
+  }
 }
 
 .navbar-nav {

app/assets/stylesheets/pages/search.scss

@@ -29,7 +29,7 @@ input[type="checkbox"]:hover {
 }
 
 .search {
-  margin: 4px 8px 0;
+  margin: 0 8px;
 
   form {
     @extend .form-control;

app/views/layouts/header/_default.html.haml

@@ -61,7 +61,7 @@
           - if header_link?(:sign_in)
             %li.nav-item
               %div
-                = link_to "Sign in / Register", new_session_path(:user, redirect_to_referer: 'yes'), class: 'nav-link btn btn-sign-in'
+                = link_to "Sign in / Register", new_session_path(:user, redirect_to_referer: 'yes'), class: 'btn btn-sign-in'
 
       %button.navbar-toggler.d-block.d-sm-none{ type: 'button' }
         %span.sr-only Toggle navigation