style.css

* {
    border: 0;
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

:root {
    --bg: #032241;
    --fg: #e3e4e8;
    --fg-t: rgba(227, 228, 232, 0.5);
    --primary1: #00509f;
    --primary2: #0b42cb;
    --trans-dur: 0.3s;
    font-size: calc(16px + (20 - 16) * (100vw - 320px) / (1280 - 320));
}

body {
    background-color: var(--bg);
    background-image: linear-gradient(135deg, rgba(0, 0, 0, 0), rgba(0, 0, 0, 0.2));
    color: var(--fg);
    font: 1em/1.5 "Varela Round", Helvetica, sans-serif;
    height: 100vh;
    min-height: 360px;
    display: grid;
    place-items: center;
    transition: background-color var(--trans-dur), color var(--trans-dur);
}

.pl {
    box-shadow: 2em 0 2em rgba(0, 0, 0, 0.2) inset, -2em 0 2em rgba(255, 255, 255, 0.1) inset;
    display: flex;
    justify-content: center;
    align-items: center;
    position: relative;
    letter-spacing: 0.1em;
    text-transform: uppercase;
    transform: rotateX(30deg) rotateZ(45deg);
    width: 15em;
    height: 15em;
}

.pl,
.pl__dot {
    border-radius: 50%;
}

.pl__dot {
    animation-name: shadow;
    box-shadow: 0.1em 0.1em 0 0.1em black, 0.3em 0 0.3em rgba(0, 0, 0, 0.5);
    top: calc(50% - 0.75em);
    left: calc(50% - 0.75em);
    width: 1.5em;
    height: 1.5em;
}

.pl__dot,
.pl__dot:before,
.pl__dot:after {
    animation-duration: 2s;
    animation-iteration-count: infinite;
    position: absolute;
}

.pl__dot:before,
.pl__dot:after {
    content: "";
    display: block;
    left: 0;
    width: inherit;
    transition: background-color var(--trans-dur);
}

.pl__dot:before {
    animation-name: pushInOut1;
    background-color: var(--bg);
    border-radius: inherit;
    box-shadow: 0.05em 0 0.1em rgba(255, 255, 255, 0.2) inset;
    height: inherit;
    z-index: 1;
}

.pl__dot:after {
    animation-name: pushInOut2;
    background-color: var(--primary1);
    border-radius: 0.75em;
    box-shadow: 0.1em 0.3em 0.2em rgba(255, 255, 255, 0.4) inset, 0 -0.4em 0.2em #2e3138 inset, 0 -1em 0.25em rgba(0, 0, 0, 0.3) inset;
    bottom: 0;
    clip-path: polygon(0 75%, 100% 75%, 100% 100%, 0 100%);
    height: 3em;
    transform: rotate(-45deg);
    transform-origin: 50% 2.25em;
}

.pl__dot:nth-child(1) {
    transform: rotate(0deg) translateX(5em) rotate(0deg);
    z-index: 5;
}

.pl__dot:nth-child(1),
.pl__dot:nth-child(1):before,
.pl__dot:nth-child(1):after {
    animation-delay: 0s;
}

.pl__dot:nth-child(2) {
    transform: rotate(-30deg) translateX(5em) rotate(30deg);
    z-index: 4;
}

.pl__dot:nth-child(2),
.pl__dot:nth-child(2):before,
.pl__dot:nth-child(2):after {
    animation-delay: -0.1666666667s;
}

.pl__dot:nth-child(3) {
    transform: rotate(-60deg) translateX(5em) rotate(60deg);
    z-index: 3;
}

.pl__dot:nth-child(3),
.pl__dot:nth-child(3):before,
.pl__dot:nth-child(3):after {
    animation-delay: -0.3333333333s;
}

.pl__dot:nth-child(4) {
    transform: rotate(-90deg) translateX(5em) rotate(90deg);
    z-index: 2;
}

.pl__dot:nth-child(4),
.pl__dot:nth-child(4):before,
.pl__dot:nth-child(4):after {
    animation-delay: -0.5s;
}

.pl__dot:nth-child(5) {
    transform: rotate(-120deg) translateX(5em) rotate(120deg);
    z-index: 1;
}

.pl__dot:nth-child(5),
.pl__dot:nth-child(5):before,
.pl__dot:nth-child(5):after {
    animation-delay: -0.6666666667s;
}

.pl__dot:nth-child(6) {
    transform: rotate(-150deg) translateX(5em) rotate(150deg);
    z-index: 1;
}

.pl__dot:nth-child(6),
.pl__dot:nth-child(6):before,
.pl__dot:nth-child(6):after {
    animation-delay: -0.8333333333s;
}

.pl__dot:nth-child(7) {
    transform: rotate(-180deg) translateX(5em) rotate(180deg);
    z-index: 2;
}

.pl__dot:nth-child(7),
.pl__dot:nth-child(7):before,
.pl__dot:nth-child(7):after {
    animation-delay: -1s;
}

.pl__dot:nth-child(8) {
    transform: rotate(-210deg) translateX(5em) rotate(210deg);
    z-index: 3;
}

.pl__dot:nth-child(8),
.pl__dot:nth-child(8):before,
.pl__dot:nth-child(8):after {
    animation-delay: -1.1666666667s;
}

.pl__dot:nth-child(9) {
    transform: rotate(-240deg) translateX(5em) rotate(240deg);
    z-index: 4;
}

.pl__dot:nth-child(9),
.pl__dot:nth-child(9):before,
.pl__dot:nth-child(9):after {
    animation-delay: -1.3333333333s;
}

.pl__dot:nth-child(10) {
    transform: rotate(-270deg) translateX(5em) rotate(270deg);
    z-index: 5;
}

.pl__dot:nth-child(10),
.pl__dot:nth-child(10):before,
.pl__dot:nth-child(10):after {
    animation-delay: -1.5s;
}

.pl__dot:nth-child(11) {
    transform: rotate(-300deg) translateX(5em) rotate(300deg);
    z-index: 6;
}

.pl__dot:nth-child(11),
.pl__dot:nth-child(11):before,
.pl__dot:nth-child(11):after {
    animation-delay: -1.6666666667s;
}

.pl__dot:nth-child(12) {
    transform: rotate(-330deg) translateX(5em) rotate(330deg);
    z-index: 6;
}

.pl__dot:nth-child(12),
.pl__dot:nth-child(12):before,
.pl__dot:nth-child(12):after {
    animation-delay: -1.8333333333s;
}

.pl__text {
    font-size: 0.75em;
    max-width: 5rem;
    position: relative;
    text-shadow: 0 0 0.1em var(--fg-t);
    transform: rotateZ(-45deg);
}

/* Animations */
@keyframes shadow {
    from {
        animation-timing-function: ease-in;
        box-shadow: 0.1em 0.1em 0 0.1em black, 0.3em 0 0.3em rgba(0, 0, 0, 0.3);
    }

    25% {
        animation-timing-function: ease-out;
        box-shadow: 0.1em 0.1em 0 0.1em black, 0.8em 0 0.8em rgba(0, 0, 0, 0.5);
    }

    50%,
    to {
        box-shadow: 0.1em 0.1em 0 0.1em black, 0.3em 0 0.3em rgba(0, 0, 0, 0.3);
    }
}

@keyframes pushInOut1 {
    from {
        animation-timing-function: ease-in;
        background-color: var(--bg);
        transform: translate(0, 0);
    }

    25% {
        animation-timing-function: ease-out;
        background-color: var(--primary2);
        transform: translate(-71%, -71%);
    }

    50%,
    to {
        background-color: var(--bg);
        transform: translate(0, 0);
    }
}

@keyframes pushInOut2 {
    from {
        animation-timing-function: ease-in;
        background-color: var(--bg);
        clip-path: polygon(0 75%, 100% 75%, 100% 100%, 0 100%);
    }

    25% {
        animation-timing-function: ease-out;
        background-color: var(--primary1);
        clip-path: polygon(0 25%, 100% 25%, 100% 100%, 0 100%);
    }

    50%,
    to {
        background-color: var(--bg);
        clip-path: polygon(0 75%, 100% 75%, 100% 100%, 0 100%);
    }
}