style(admin): update login page background styling

- Set body background color to #333333
- Move background image from container to body element
- Remove background color from container element

Signed-off-by: wolfcode <37436228+wolf-leo@users.noreply.github.com>

public/static/admin/css/login.css

@@ -1,3 +1,6 @@
+body {
+    background: #333333;
+}
 
 .demo {
     padding-top: 20px;
@@ -170,7 +173,6 @@
 }
 
 .container {
-    background: #333333;
     position: static;
     font-size: 12px;
     height: 100%;

public/static/admin/js/login.js

@@ -7,7 +7,7 @@ define(["jquery", "easy-admin"], function ($, ea) {
             }
             $(function () {
                 if (backgroundUrl) {
-                    $('.container').css('background', 'url(' + backgroundUrl + ') 0% 0% / cover no-repeat')
+                    $('body').css('background', 'url(' + backgroundUrl + ') 0% 0% / cover no-repeat')
                 }
                 $('.bind-password').on('click', function () {
                     if ($(this).hasClass('icon-5')) {