Column not center aligned on mobile device

Question

I've created a WP site and on the homepage I've added a HTML widget with 3 columns. Everything is good except on mobile device the 3 columns are off to the right of the screen. I can't seem to center them when viewed on mobile as seen in the image below.

<div class="wrapper">
<!-- wp:columns {"columns":3} -->
<div class="wp-block-columns has-3-columns">
<!-- wp:column -->

<div class="wp-block-column"><!-- wp:heading -->
<h2>News</h2>
<!-- /wp:heading -->

<!-- wp:image {"id":482,"align":"center","linkDestination":"custom"} -->
<div class="wp-block-image"><figure class="aligncenter"><a href="http://www.patricianprimaryschool.ie/home/newsletter/"><img src="http://www.patricianprimaryschool.ie/wp-content/uploads/2019/03/Newsletter.png" alt="" class="wp-image-482"/></a> . 
</figure></div>
<!-- /wp:image --></div>
        <!-- /wp:column -->

<!-- wp:column -->
<div class="wp-block-column">
<!-- wp:heading -->
<h2>Calendar</h2>
<!-- /wp:heading -->

<!-- wp:image {"id":481,"align":"center","linkDestination":"custom"} -->
<div class="wp-block-image"><figure class="aligncenter"><a href="http://www.patricianprimaryschool.ie/home/school-calender/"><img src="http://www.patricianprimaryschool.ie/wp-content/uploads/2019/03/SchoolCalendar-01-1024x1024.png" alt="" class="wp-image-481"/></a></figure></div>
<!-- /wp:image --></div>
        <!-- /wp:column -->


<div class="wp-block-column twitterContainer">
<!-- wp:column -->

<!-- wp:heading -->
<h2>Follow Us</h2>
<!-- /wp:heading -->

<!-- wp:html -->
<a class="twitter-timeline" data-height="300" data-theme="light" href="https://twitter.com/PPSNewbridge?ref_src=twsrc%5Etfw">Tweets by PPSNewbridge</a> <script async src="https://platform.twitter.com/widgets.js" charset="utf-8"></script>
<!-- /wp:html -->
<!-- /wp:column --></div></div></div>
<!-- /wp:columns -->

And my CSS:

 .wp-block-column {
min-width: 220px; 
max-width: 550px; 
}


.wp-block-columns {
margin: 112px;
}

.wp-block-column  {
border: 2px solid #354063;
padding: 2px 10px;
}

Answer 1

Your column divs have maximum width 550px and the parent div has 112px margin. When the screen size is less than (550+120*2) = 790px, the columns are aligning right. To prevent this, use margin 0 when the screen size is less than 800px. Use the following CSS to do that.

@media only screen and (max-width: 800px) {
  .wp-block-columns {
    margin: 0px;
  }
}