:hover not working on svg when svg is in external file

So I'm learning SVG animation.

Basically all I'm trying to do is change the color of a circle when it's hovered over.

<svg version="1.1" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink" x="0px" y="0px"
 viewBox="0 0 437.1 294.4" style="enable-background:new 0 0 437.1 294.4;" xml:space="preserve">

    <style type="text/css">

        .st0:hover {
            fill: red;
         }

    </style>

    <g id="Circle">
        <path class="st0" d="M291.3,147.4c0,77-62.4,139.4-139.4,139.4S12.5,224.4,12.5,147.4C12.6,70.4,75,8,151.9,8
        C228.9,8,291.3,70.4,291.3,147.4"/>
    </g>

</svg>

This works exactly as expected when the svg code is inside the html file.

However, when I put it inside an svg file and call it in using the img tag the hover effect no longer works.

<img class="logo" src="url/logo.svg">

Is there a way to do this without embedding the svg code inside the html?

Thanks!

Solution

Can't be done with the <img> tag. See: Styling And Animating SVGs With CSS. Near the bottom of the page of this article there's a table with the pros and cons of each SVG embedding technique (ie, img, object, etc.). I have reproduced the table here:

|                      | CSS Interactions | CSS Animations | SVG Animations |
|:--------------------:|:----------------:|:--------------:|:--------------:|
|         <img>        |        No        |      Yes*      |       Yes      |
| CSS background image |        No        |      Yes*      |       Yes      |
|       <object>       |       Yes*       |      Yes*      |       Yes      |
|       <iframe>       |       Yes*       |      Yes*      |       Yes      |
|        <embed>       |       Yes*       |      Yes*      |       Yes      |
|    <svg> (inline)    |        Yes       |       Yes      |       Yes      |

*Only if inside <svg>