Add notification center button and fix stat-card/activity board loading

static/admin/css/login.css

@@ -1,7 +1,7 @@
 /* LOGIN FORM */
 
 .login {
-    background: #f8f8f8;
+    background: var(--darkened-bg);
     height: auto;
 }
 
@@ -12,11 +12,12 @@
 }
 
 .login #header h1 {
-    font-size: 18px;
+    font-size: 1.125rem;
+    margin: 0;
 }
 
 .login #header h1 a {
-    color: #fff;
+    color: var(--header-link-color);
 }
 
 .login #content {
@@ -24,8 +25,8 @@
 }
 
 .login #container {
-    background: #fff;
-    border: 1px solid #eaeaea;
+    background: var(--body-bg);
+    border: 1px solid var(--hairline-color);
     border-radius: 4px;
     overflow: hidden;
     width: 28em;
@@ -34,44 +35,25 @@
     height: auto;
 }
 
-.login #content-main {
-    width: 100%;
-}
-
 .login .form-row {
     padding: 4px 0;
-    float: left;
-    width: 100%;
-    border-bottom: none;
 }
 
 .login .form-row label {
-    padding-right: 0.5em;
+    display: block;
     line-height: 2em;
-    font-size: 1em;
-    clear: both;
-    color: #333;
 }
 
 .login .form-row #id_username, .login .form-row #id_password {
-    clear: both;
     padding: 8px;
     width: 100%;
     box-sizing: border-box;
 }
 
-.login span.help {
-    font-size: 10px;
-    display: block;
-}
-
 .login .submit-row {
-    clear: both;
-    padding: 1em 0 0 9.4em;
+    padding: 1em 0 0 0;
     margin: 0;
-    border: none;
-    background: none;
-    text-align: left;
+    text-align: center;
 }
 
 .login .password-reset-link {