Webleb - UI Elements - pulse loading

HTML

<!DOCTYPE html>
<html lang="pt-BR">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Carregamento pulsante</title>
    <style>

/* fundo preto, tudo alinhado no centro, 100vh e 100vw*/
        body {
            display: flex;
            justify-content: center;
            align-items: center;
            width: 100vw;
            height: 100vh;
            background: black;
            font-family: Arial, sans-serif;
            margin: 0;
            padding: 0;
        }

/* anel que ficará em volta do circulo com animacao para pulsar */
        .carregamento-pulsante {
            width: 150px;
            height: 150px;
            border-radius: 50%;
            background: transparent;
            border: 4px solid #3498db;
            box-shadow: 0 0 10px rgba(52, 152, 219, 0.5);
            outline: none;
            position: relative;
            animation: animacaoPulsante 0.6s ease-in-out infinite;
        }
        /* usando o after para colocar o circulo dentro, com 50% left e 50% top*/
        .carregamento-pulsante::after {
            content: '';
            position: absolute;
            top: 50%;
            left: 50%;
            width: 20px;
            height: 20px;
            background: #3498db;
            border-radius: 50%;
            transform: translate(-50%, -50%);
            box-shadow: 0 0 8px #3498db;
        }
        /* animacao para pulsar*/
        @keyframes animacaoPulsante {
            0% {
                transform: scale(0);
                opacity: 0.9;
            }
            100% {
                transform: scale(1);
                opacity: 0;
            }
        }
    </style>
</head>

</body>
</html>

CSS

JS