Orbital :: WordPress Login Form :: adapted by brasofilo, original code by https://codepen.io/guerreiro/pen/rNZajZ

inject.html

<div id="logoBox">
  <svg viewBox="0 0 160 160" width="160" height="160">
    <circle cx="80" cy="80" r="50" />
    <g transform=" matrix(0.866, -0.5, 0.25, 0.433, 80, 80)">
      <path d="M 0,70 A 65,70 0 0,0 65,0 5,5 0 0,1 75,0 75,70 0 0,1 0,70Z" fill="#FFF">
        <animateTransform attributeName="transform" type="rotate" from="360 0 0" to="0 0 0" dur="1s" repeatCount="indefinite" />
      </path>
    </g>
    <path d="M 50,0 A 50,50 0 0,0 -50,0Z" transform="matrix(0.866, -0.5, 0.5, 0.866, 80, 80)" />
  </svg>
</div>

login.css

/* Admin Tweaks: https://wordpress.org/plugins/many-tips-together */

/* Hide stuff as you wish, set a bg color and add the following CSS */

/* Add CSS */
svg {
    position: fixed;
    top: 20%;
    height: 60%;
    left: 20%;
    width: 60%;
}
#logoBox * { 
    z-index: -9999999
}
	
#login > h1 {
    display: none;
}				
#loginform {
    background: none;
}				
#login {
    width: 250px;
    position: absolute;
    top: 46%;
    transform: translateX(-50%) translateY(-50%);
    left: 50%;
}