fix: import components styles in App scss (#2737)

Author: artemmufazalov

src/containers/App/App.scss

@@ -1,5 +1,9 @@
 @use '../../styles/mixins.scss';
 
+@forward '../../styles/drawer.scss';
+@forward '../../styles/versions.scss';
+@forward '../../styles/unipika.scss';
+
 @import url('https://fonts.googleapis.com/css2?family=Rubik&display=swap');
 
 * {

src/styles/drawer.scss

@@ -0,0 +1,6 @@
+.g-root {
+    --ydb-drawer-veil-z-index: 2;
+    --gn-drawer-item-z-index: calc(var(--ydb-drawer-veil-z-index) + 1);
+
+    --gn-drawer-veil-z-index: var(--ydb-drawer-veil-z-index);
+}

src/styles/index.scss

@@ -1,14 +1,8 @@
 @forward '@gravity-ui/uikit/styles/styles.scss';
 @forward './themes.scss';
-@forward './unipika.scss';
 @forward './illustrations.scss';
-@forward './versions.scss';
 
 body {
-    --ydb-drawer-veil-z-index: 2;
-    --gn-drawer-item-z-index: calc(var(--ydb-drawer-veil-z-index) + 1);
-
-    --gn-drawer-veil-z-index: var(--ydb-drawer-veil-z-index);
     margin: 0;
 
     font-family: