<div class="block"></div>

body {
    min-height: 100vh;
    margin: 0;
    padding: 32px;
    box-sizing: border-box;
    display: grid;
    background-color: #282C32;
}

.block {
    border-radius: 4px;
    box-shadow:
        inset 0 0 2px 1px rgba(122 230 255 / 30%),
        inset 0 0 4px 2px rgba(122 230 255 / 25%),
        inset 0 0 8px 4px rgba(122 230 255 / 20%),
        inset 0 0 16px 8px rgba(122 230 255 / 15%);
}