style.css

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    font-family: 'Lucida Sans', sans-serif;
}

body {
    height: 100vh;
    background-color: #131221;
}

body,
.container,
.overlay {
    display: flex;
    align-items: center;
    justify-content: center;
}

.container {
    position: relative;
    height: 450px;
    width: 350px;
    border-radius: 16px;
    background-color: #fff;
    overflow: hidden;
}

.container.active {
    background-color: #000;
}

.container::before {
    content: "";
    position: absolute;
    height: 650px;
    width: 650px;
    background-image: conic-gradient(transparent, transparent, transparent, #fff);
}

.container.active:before {
    animation: rotate 4s linear infinite;
}

@keyframes rotate {
    0% {
        transform: rotate(0deg);
    }

    100% {
        transform: rotate(360deg);
    }
}

.container .overlay {
    position: absolute;
    height: 440px;
    width: 340px;
    font-size: 40px;
    font-weight: 500;
    color: #fff;
    border-radius: 12px;
    background-color: #131221;
}