Show JS Unable to scroll slides

Question

I am using Reveal JS to create a presentation.

If I put more text in the tag, it will be below the screen hidden from the view. But there is no scroll bar on the right. Wonder if I can do a css fix to insert a vertical scrollbar and make hidden content visible by scrolling.

Here is the CSS that needs to be changed (I think)

.reveal .slides section .fragment {
    opacity: 0;

    -webkit-transition: all .2s ease;
       -moz-transition: all .2s ease;
        -ms-transition: all .2s ease;
         -o-transition: all .2s ease;
            transition: all .2s ease;
}
    .reveal .slides section .fragment.visible {
        opacity: 1;
    }

.reveal .slides section .fragment.grow {
    opacity: 1;
}
    .reveal .slides section .fragment.grow.visible {
        -webkit-transform: scale( 1.3 );
           -moz-transform: scale( 1.3 );
            -ms-transform: scale( 1.3 );
             -o-transform: scale( 1.3 );
                transform: scale( 1.3 );
    }

.reveal .slides section .fragment.shrink {
    opacity: 1;
}
    .reveal .slides section .fragment.shrink.visible {
        -webkit-transform: scale( 0.7 );
           -moz-transform: scale( 0.7 );
            -ms-transform: scale( 0.7 );
             -o-transform: scale( 0.7 );
                transform: scale( 0.7 );
    }

.reveal .slides section .fragment.zoom-in {
    opacity: 0;

    -webkit-transform: scale( 0.1 );
       -moz-transform: scale( 0.1 );
        -ms-transform: scale( 0.1 );
         -o-transform: scale( 0.1 );
            transform: scale( 0.1 );
}

    .reveal .slides section .fragment.zoom-in.visible {
        opacity: 1;

        -webkit-transform: scale( 1 );
           -moz-transform: scale( 1 );
            -ms-transform: scale( 1 );
             -o-transform: scale( 1 );
                transform: scale( 1 );
    }

.reveal .slides section .fragment.roll-in {
    opacity: 0;

    -webkit-transform: rotateX( 90deg );
       -moz-transform: rotateX( 90deg );
        -ms-transform: rotateX( 90deg );
         -o-transform: rotateX( 90deg );
            transform: rotateX( 90deg );
}
    .reveal .slides section .fragment.roll-in.visible {
        opacity: 1;

        -webkit-transform: rotateX( 0 );
           -moz-transform: rotateX( 0 );
            -ms-transform: rotateX( 0 );
             -o-transform: rotateX( 0 );
                transform: rotateX( 0 );
    }

.reveal .slides section .fragment.fade-out {
    opacity: 1;
}
    .reveal .slides section .fragment.fade-out.visible {
        opacity: 0;
    }

.reveal .slides section .fragment.semi-fade-out {
    opacity: 1;
}
    .reveal .slides section .fragment.semi-fade-out.visible {
        opacity: 0.5;
    }

.reveal .slides section .fragment.highlight-red,
.reveal .slides section .fragment.highlight-green,
.reveal .slides section .fragment.highlight-blue {
    opacity: 1;
}
    .reveal .slides section .fragment.highlight-red.visible {
        color: #ff2c2d
    }
    .reveal .slides section .fragment.highlight-green.visible {
        color: #17ff2e;
    }
    .reveal .slides section .fragment.highlight-blue.visible {
        color: #1b91ff;
    }

Answer 1

I solved this with:

.scrollable {
    overflow-y: auto  !important;
    overflow-x: hidden !important;
    height: 700px;
}

add the top class to the slide tag (section) to make it scrollable.