Redesign forms, verify link ownership with rel="me" (#8703)

* Verify link ownership with rel="me"

* Add explanation about verification to UI

* Perform link verifications

* Add click-to-copy widget for verification HTML

* Redesign edit profile page

* Redesign forms

* Improve responsive design of settings pages

* Restore landing page sign-up form

* Fix typo

* Support <link> tags, add spec

* Fix links not being verified on first discovery and passive updates

app/javascript/styles/mastodon/admin.scss

@@ -1,3 +1,5 @@
+$no-columns-breakpoint: 600px;
+
 .admin-wrapper {
   display: flex;
   justify-content: center;
@@ -24,12 +26,22 @@
       height: 100px;
     }
 
+    @media screen and (max-width: $no-columns-breakpoint) {
+      & > a:first-child {
+        display: none;
+      }
+    }
+
     ul {
       list-style: none;
       border-radius: 4px 0 0 4px;
       overflow: hidden;
       margin-bottom: 20px;
 
+      @media screen and (max-width: $no-columns-breakpoint) {
+        margin-bottom: 0;
+      }
+
       a {
         display: block;
         padding: 15px;
@@ -62,19 +74,23 @@
         a {
           border: 0;
           padding: 15px 35px;
-
-          &.selected {
-            color: $primary-text-color;
-            background-color: $ui-highlight-color;
-            border-bottom: 0;
-            border-radius: 0;
-
-            &:hover {
-              background-color: lighten($ui-highlight-color, 5%);
-            }
-          }
         }
       }
+
+      .simple-navigation-active-leaf a {
+        color: $primary-text-color;
+        background-color: $ui-highlight-color;
+        border-bottom: 0;
+        border-radius: 0;
+
+        &:hover {
+          background-color: lighten($ui-highlight-color, 5%);
+        }
+      }
+    }
+
+    & > ul > .simple-navigation-active-leaf a {
+      border-radius: 4px 0 0 4px;
     }
   }
 
@@ -89,11 +105,19 @@
     padding-top: 60px;
     padding-left: 25px;
 
+    @media screen and (max-width: $no-columns-breakpoint) {
+      max-width: none;
+      padding: 15px;
+      padding-top: 30px;
+    }
+
     h2 {
       color: $secondary-text-color;
       font-size: 24px;
       line-height: 28px;
       font-weight: 400;
+      padding-bottom: 40px;
+      border-bottom: 1px solid lighten($ui-base-color, 8%);
       margin-bottom: 40px;
     }
 
@@ -108,7 +132,7 @@
     h4 {
       text-transform: uppercase;
       font-size: 13px;
-      font-weight: 500;
+      font-weight: 700;
       color: $darker-text-color;
       padding-bottom: 8px;
       margin-bottom: 8px;
@@ -122,6 +146,11 @@
       font-weight: 400;
     }
 
+    .fields-group h6 {
+      color: $primary-text-color;
+      font-weight: 500;
+    }
+
     & > p {
       font-size: 14px;
       line-height: 18px;
@@ -172,30 +201,7 @@
     }
   }
 
-  .simple_form {
-    max-width: 400px;
-
-    &.edit_user,
-    &.new_form_admin_settings,
-    &.new_form_two_factor_confirmation,
-    &.new_form_delete_confirmation,
-    &.new_import,
-    &.new_domain_block,
-    &.edit_domain_block {
-      max-width: none;
-    }
-
-    .form_two_factor_confirmation_code,
-    .form_delete_confirmation_password {
-      max-width: 400px;
-    }
-
-    .actions {
-      max-width: 400px;
-    }
-  }
-
-  @media screen and (max-width: 600px) {
+  @media screen and (max-width: $no-columns-breakpoint) {
     display: block;
     overflow-y: auto;
     -webkit-overflow-scrolling: touch;
@@ -209,16 +215,8 @@
 
     .sidebar {
       width: 100%;
-      padding: 10px 0;
+      padding: 0;
       height: auto;
-
-      .logo {
-        margin: 20px auto;
-      }
-    }
-
-    .content {
-      padding-top: 20px;
     }
   }
 }