Svg Use. Embedded SVGs can be styled using CSS. Such references are taken to be referring to the root element of the referenced document.
Most browsers that supported inline SVG supported this. For that you need to use as shown in Nicks answer. Such references are taken to be referring to the root element of the referenced document.
For href defines a URL referring to an element or fragment within an SVG document to be cloned.
Adding height width viewBox and CSS rules seems to be the best workaround. The element can reference an entire SVG document by specifying an href value without a fragment. For that you need to use as shown in Nicks answer. It is absolutely not required but if you like this website any.