HTMLify

body {
    display: grid;
    place-items: center;
    height: 100vh;
    background: #121314;
    margin: 0;
    padding: 0;
}

.hamburger {
    position: absolute;
    width: 80px;
    cursor: pointer;
}

span {
    display: block;
    width: 100%;
    box-shadow: 0 2px 10px 0 rgba(0, 0, 0, 0.3);
    border-radius: 3px;
    height: 8px;
    background: #fff;
    transition: all .3s;
    position: relative;
}

span+span {
    margin-top: 14px;
}

.active span:nth-child(1) {
    animation: ease .7s topBar forwards;
}

.not-active span:nth-child(1) {
    animation: ease .7s topBarRotate forwards;
}

.active span:nth-child(2) {
    animation: ease .7s middleBar forwards;
}

.not-active span:nth-child(2) {
    animation: ease .7s middleBarScale forwards;
}

.active span:nth-child(3) {
    animation: ease .7s bottomBar forwards;
}

.not-active span:nth-child(3) {
    animation: ease .7s bottomBarRotate forwards;
}

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

    50% {
        top: 22px;
        transform: rotate(0);
    }

    100% {
        top: 22px;
        transform: rotate(45deg);
    }
}

@keyframes topBarRotate {
    0% {
        top: 22px;
        transform: rotate(45deg);
    }

    50% {
        top: 22px;
        transform: rotate(0deg);
    }

    100% {
        top: 0;
        transform: rotate(0deg);
    }
}

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

    50% {
        bottom: 22px;
        transform: rotate(0);
    }

    100% {
        bottom: 22px;
        transform: rotate(135deg);
    }
}

@keyframes bottomBarRotate {
    0% {
        bottom: 22px;
        transform: rotate(135deg);
    }

    50% {
        bottom: 22px;
        transform: rotate(0);
    }

    100% {
        bottom: 0;
        transform: rotate(0);
    }
}

@keyframes middleBar {
    50% {
        transform: scale(0);
    }

    100% {
        transform: scale(0);
    }
}

@keyframes middleBarScale {
    0% {
        transform: scale(0);
    }

    50% {
        transform: scale(0);
    }

    100% {
        transform: scale(1);
    }
}