Untitled

<html>
    <head>
<style>
html, body {
    height: 100%;
}
body {
    margin: 0;
    background: #263238;
    display: flex;
    justify-content: center;
    align-items: center;
}
#spinner {
    width: 200px;
    height: 200px;
    animation: spin 1s infinite linear;
}
@keyframes spin {
    from {
        transform: rotate(0);
    }
    to {
        transform: rotate(360deg);
    }
}
</style>
    </head>
    <body>
        <img id="spinner" src="nightuicon.png">
    </body>
</html>