I have a 1 liner JS in the footer and I can't get getElementsByClassName to work to tweak style attributes. "Hello World" works, so it must be my syntax?

The footer code is this:

```
<script>
var test = document.getElementsByClassName("elementor-widget-container");
test.style.background-color = 'white';  
var widgets = document.getElementsByClassName("widgets_wrapper");
widgets.style.margin = "0px";
</script>

```