chore: minor code cleanup

Author: jooy2

src/renderer/screens/MainScreen.tsx

@@ -38,15 +38,15 @@ export default function MainScreen() {
     <div css={bodyRoot}>
       <div css={jumbo}>
         <Grid container alignItems="center" spacing={3}>
-          <Grid size={{ xs: 5 }}>
+          <Grid size={5}>
             <img
               data-testid="main-logo"
               alt="logo"
               src="images/retron-logo.webp"
               draggable="false"
             />
           </Grid>
-          <Grid size={{ xs: 7 }}>
+          <Grid size={7}>
             <h1>{t('hello-title')}</h1>
             <p>{t('hello-desc')}</p>
             <p>