Fix/manga screen prevent fab from overlaying last chapter in list (#298)

* Introduce "StyledFAb"

MUI "Fab" with the "default" styling applied

* Prevent FAB from overlaying last chapter in list of Manga details page

src/components/manga/SelectionFAB.tsx

@@ -12,6 +12,7 @@ import React, { useRef, useState } from 'react';
 import type { IChapterWithMeta } from 'components/manga/ChapterList';
 import SelectionFABActionItem from 'components/manga/SelectionFABActionItem';
 import { useTranslation } from 'react-i18next';
+import { DEFAULT_FAB_STYLE } from 'components/util/StyledFab';
 
 export type SelectionAction = 'download' | 'delete' | 'bookmark' | 'unbookmark' | 'mark_as_read' | 'mark_as_unread';
 
@@ -38,9 +39,8 @@ const SelectionFAB: React.FC<SelectionFABProps> = (props) => {
     return (
         <Box
             sx={{
-                position: 'fixed',
-                bottom: '2em',
-                right: '3em',
+                ...DEFAULT_FAB_STYLE,
+                height: `calc(${DEFAULT_FAB_STYLE.height} + 1)`,
                 pt: 1,
             }}
             ref={anchorEl}