Example how to pass CSS-class to child component

App.xht

<script>
    import Icon from './Icon.xht';
    let name = 'world';
</script>

<Icon />
<Icon .icon="green bold" />
<br/>
<Icon .icon="aqua big" />

<style>
    .aqua {
        stroke: cornflowerblue;
        fill: aqua;
    }
    .green {
        fill: lightgreen;
        stroke: darkgreen;
    }
    .bold {
        stroke-width: 8;
    }
    .big {
        width: 200px;
        height: 200px;
    }
</style>

Icon.xht

<svg class="icon" width="100" height="100" viewBox="0 0 100 100" xmlns="http://www.w3.org/2000/svg">
  <path d="M 10,30
       A 20,20 0,0,1 50,30
       A 20,20 0,0,1 90,30
       Q 90,60 50,90
       Q 10,60 10,30 z" />
</svg>

<style>
    :export(.icon) {
        stroke: red;
        fill: hotpink;
    }
</style>