fix: Re-add the page margin for pages that need it

frontend/src/pages/dashboard.tsx

@@ -65,7 +65,7 @@ export default class Dashboard extends React.Component<IProps> {
 
         const level = this.props.nextLevel;
 
-        return <div>
+        return <div className="content">
             <Grid container direction={direction} spacing={16}>
                 <Grid item lg={4}>
                     <Paper className="paper">

frontend/src/pages/intro.tsx

@@ -17,7 +17,7 @@ export default class IntroPage extends React.Component<IProps> {
     render() {
         const small = window.matchMedia("(max-width: 700px)").matches;
         const cName = small ? "intro-card-xs" : "intro-card-lg";
-        return <div>
+        return <div className="content">
             <Grid container justify="center">
                 <Card className={cName}>
                     <CardContent>

frontend/src/pages/levelList.tsx

@@ -81,7 +81,7 @@ const LevelListWithRouter = withRouter(
                 const suffix = levels.indexOf(level.level) !== -1 ? " ✔" : "";
                 return <Grid item key={key++}>
                     <Card style={{
-                        width: small ? window.width - 32 : "300px"
+                        width: small ? window.innerWidth - 32 : "300px"
                     }}>
                         <CardContent className={cName}>
                             <Typography variant="title">{`Level ${level.level}${suffix}`}</Typography>
@@ -102,7 +102,7 @@ const LevelListWithRouter = withRouter(
                 </Grid>;
             };
 
-            return <div>
+            return <div className="content">
                 <Grid container spacing={16} direction="row">
                     {this.props.levels.map(levelToCard)}
                 </Grid>

frontend/src/pages/login.tsx

@@ -82,7 +82,7 @@ const LoginPageWithRouter = withRouter(
                 }
             };
 
-            return <div>
+            return <div className="content">
                 <Grid
                     container
                     spacing={0}

frontend/src/pages/register.tsx

@@ -91,7 +91,7 @@ const RegisterPageWithRouter = withRouter(
                 }
             };
 
-            return <div>
+            return <div className="content">
                 <Grid
                     container
                     spacing={0}

frontend/src/pages/review.tsx

@@ -382,7 +382,7 @@ const ReviewPageWithRouter = withRouter(
                     100 * (numCards - (this.reviewQueue.size() + 1)) / numCards
                 );
 
-            return <div>
+            return <div className="content">
                 <Grid container justify="center">
                     <Grid item style={{ width: "100%" }}>
                         <Card>

frontend/src/pages/summary.tsx

@@ -29,7 +29,7 @@ const SummaryPageWithRouter = withRouter(
         }
 
         render() {
-            return <div>
+            return <div className="content">
                 <Grid
                     container
                     spacing={0}