Css how to style a div inside a custom angular component

Question

I would like to style the inner class which is inside the custom angular component

<div class="outer">
    <custom-component>
        <div class="inner">
        </div>
    </custom-component>
<div>

css: Following style is not working.

.outer {
    custom-component > .inner {
        border: solid 1px orange;
    }   
}