HTMLify

@import url("https://fonts.googleapis.com/css?family=Montserrat");

body {
    background: #333;
    overflow: hidden;
    font-family: "Montserrat", sans-serif;
}

.menu__container {
    display: grid;
    place-items: center;
    height: 100vh;
    width: 100vw;
}

label {
    position: relative;
    display: grid;
    place-items: center;
    height: 50px;
    width: 65px;
    cursor: pointer;
    transition: 0.5s;
    transition-delay: 0.7s;
}

#menu {
    display: none;
}

#menu:checked~label {
    transform: translateY(-100px);
}

.hamburger {
    position: relative;
    width: 55px;
    height: 3px;
    background: #fff;
}

.hamburger::after,
.hamburger::before {
    content: "";
    position: absolute;
    background: #fff;
    width: 55px;
    height: 3px;
    transition: 0.5s;
    transition-delay: 0.2s;
}

.hamburger::after {
    top: -10px;
}

.hamburger::before {
    top: 10px;
}

#menu:checked~label .hamburger {
    animation: rotateIt 0.5s ease forwards 1;
    animation-delay: 0.6s;
}

@keyframes rotateIt {
    100% {
        transform: rotate(45deg);
    }
}

#menu:checked~label .hamburger::before {
    transform: translateY(-10px);
    opacity: 0;
    animation: moveIt 0.5s ease forwards 1;
    animation-delay: 0.6s;
}

@keyframes moveIt {
    0% {
        opacity: 1;
    }

    100% {
        transform: rotate(90deg) translateY(2px) translateX(-8px);
        opacity: 1;
        height: 3px;
    }
}

#menu:checked~label .hamburger::after {
    transform: translateY(10px);
    opacity: 0;
}

.menu__list {
    position: absolute;
    background: #fff;
    bottom: 0px;
    left: 0px;
    width: 100%;
    height: 300px;
    transition: 0.8s;
    transition-delay: 0.7s;
    overflow: hidden;
    transform: translateY(300px);
    display: flex;
    justify-content: center;
    align-items: center;
    margin: 0;
    list-style: none;
}

#menu:checked~.menu__list {
    transform: translateY(0px);
}

.menu__item {
    position: relative;
    font-size: 40px;
    margin: 0 60px;
    cursor: pointer;
}

.menu__item a {
    text-decoration: none;
    color: #333;
}

.move__item {
    position: absolute;
    height: 350px;
    width: 350px;
    background: #333;
    border-top-right-radius: 400px;
    border-bottom-right-radius: 125px;
    top: -270px;
    transition: 0.7s;
    transition-delay: 0.1s;
    transform: translateX(-250px) rotate(45deg);
    animation: menuBorder 3s linear infinite;
}

@keyframes menuBorder {
    50% {
        border-bottom-left-radius: 300px;
        border-top-right-radius: 0px;
    }
}

.menu__item::after {
    position: absolute;
    content: "";
    bottom: 0px;
    left: 0px;
    width: 100%;
    height: 4px;
}

.menu__item:nth-child(1)::after {
    background: #def06c;
}

.menu__item:nth-child(2)::after {
    background: #71c1d1;
}

.menu__item:nth-child(3)::after {
    background: #dd7171;
}

.menu__item:nth-child(1):hover~.move__item {
    transform: translate(-250px) rotate(45deg);
}

.menu__item:nth-child(2):hover~.move__item {
    transform: translate(10px) rotate(45deg);
}

.menu__item:nth-child(3):hover~.move__item {
    transform: translate(280px) rotate(45deg);
}