>I am struggling with what should be a simple task: hiding a div section on displays smaller than md.
>
>Here is just one of a sample codes I tried
>

><div class="container col-lg-12 hidden-lg-down"</div>
>

>
>What am I missing? I should I have a certain meta in the header section of the page? I have the following:
>

> <meta name="viewport" content="width=device-width, initial-scale=1">
>

>
>TIA

Don't know which version of bootstrap.css you are using. I think the current default version with VS is 3.3.7 which doesn't have the 'hidden-lg-down' (or, indeed, any '-up'/'-down' suffixes) - check the source in bootstrap.css.

If you are on 4.0 then for displays smaller than md it's hidden-sm-down.

There's a chart here: https://v4-alpha.getbootstrap.com/layout/responsive-utilities/