Compensate for scrollbar disappearing when media modal visible (#8100)

* Compensate for scrollbar disappearing when media modal visible

Make auth pages backgrounds lighter

* Fix typo

app/javascript/mastodon/containers/media_container.js

@@ -29,19 +29,19 @@ export default class MediaContainer extends PureComponent {
   };
 
   handleOpenMedia = (media, index) => {
-    document.body.classList.add('media-standalone__body');
+    document.body.classList.add('with-modals--active');
     this.setState({ media, index });
   }
 
   handleOpenVideo = (video, time) => {
     const media = ImmutableList([video]);
 
-    document.body.classList.add('media-standalone__body');
+    document.body.classList.add('with-modals--active');
     this.setState({ media, time });
   }
 
   handleCloseMedia = () => {
-    document.body.classList.remove('media-standalone__body');
+    document.body.classList.remove('with-modals--active');
     this.setState({ media: null, index: null, time: null });
   }
 

app/javascript/mastodon/features/ui/components/modal_root.js

@@ -41,14 +41,15 @@ export default class ModalRoot extends React.PureComponent {
   };
 
   getSnapshotBeforeUpdate () {
-    const visible = !!this.props.type;
-    return {
-      overflowY: visible ? 'hidden' : null,
-    };
+    return { visible: !!this.props.type };
   }
 
-  componentDidUpdate (prevProps, prevState, { overflowY }) {
-    document.body.style.overflowY = overflowY;
+  componentDidUpdate (prevProps, prevState, { visible }) {
+    if (visible) {
+      document.body.classList.add('with-modals--active');
+    } else {
+      document.body.classList.remove('with-modals--active');
+    }
   }
 
   renderLoading = modalId => () => {

app/javascript/styles/mastodon/basics.scss

@@ -1,8 +1,6 @@
 body {
   font-family: 'mastodon-font-sans-serif', sans-serif;
   background: darken($ui-base-color, 8%);
-  background-size: cover;
-  background-attachment: fixed;
   font-size: 13px;
   line-height: 18px;
   font-weight: 400;
@@ -34,16 +32,24 @@ body {
     height: 100%;
     padding: 0;
     background: $ui-base-color;
+
+    &.with-modals--active {
+      overflow-y: hidden;
+    }
   }
 
-  &.about-body {
-    background: darken($ui-base-color, 8%);
-    padding-bottom: 0;
+  &.lighter {
+    background: $ui-base-color;
   }
 
-  &.tag-body {
-    background: darken($ui-base-color, 8%);
-    padding-bottom: 0;
+  &.with-modals {
+    overflow-x: hidden;
+    overflow-y: scroll;
+
+    &--active {
+      overflow-y: hidden;
+      margin-right: 13px;
+    }
   }
 
   &.player {

app/javascript/styles/mastodon/containers.scss

@@ -60,10 +60,6 @@
   }
 }
 
-.media-standalone__body {
-  overflow: hidden;
-}
-
 .account-header {
   width: 400px;
   margin: 0 auto;