I've included code from the index.html and style.css pages are linked correctly as other elements are all working fine.

```css
.fullbox {
  border: 1px solid orange;
  background-image: url(background-image:url(/images/topmain.jpg) no-repeat;
}
```

```html
<div class="row">
  <div class="col-12">
    <div class="fullbox">
      <h2>plumbing</h2>
    </div>
  </div>
</div>
```