:root {
    --line-height: 3px;
    --scale: 8.5;
    --line-initial-width: 50px;
    --line-transition-duration: 500ms;

    --duration: 1.2s;
}

html,
body {
    height: 100%;
}

body {
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    background-color: #4a627a;
    font-family: Arial, Helvetica, sans-serif;
    color: white;
}

.container {
    height: 100px;
    display: flex;
    justify-content: center;
    align-items: center;
    flex-direction: column;
}
.line {
    width: var(--line-initial-width);
    height: var(--line-height);
    background-color: white;
}

.container {
    cursor: pointer;
}

.links {
    display: flex;
}

a {
    text-decoration: none;
    color: white;
    margin: 0 20px;
    opacity: 0;
    transition: opacity calc(var(--duration) / 3) linear 250ms, color 200ms linear;
}

a:active,
a:hover {
    color: lightgray;
}

.active > .line:nth-of-type(1) {
    animation: open-top ease-in-out var(--duration) forwards;
}

.active > .line:nth-of-type(2) {
    animation: open-bottom ease-in-out var(--duration) forwards;
}

.active a {
    opacity: 1;
}

.inactive > .line:nth-of-type(1) {
    animation: close-top ease-in-out var(--duration) forwards;
}

.inactive > .line:nth-of-type(2) {
    animation: close-bottom ease-in-out var(--duration) forwards;
}

@keyframes open-top {
    0% {
        transform: translateY(0%);
    }

    20% {
        transform: translateY(-850%);
    }

    60%,
    100% {
        transform: translateY(-850%) scaleX(var(--scale));
    }
}

@keyframes close-top {
    0% {
        transform: translateY(-850%) scaleX(var(--scale));
    }

    40% {
        transform: translateY(-850%);
    }

    60%,
    100% {
        transform: translateY(0%) scaleX(1);
    }
}

@keyframes open-bottom {
    0% {
        transform: translateY(0%);
    }

    20% {
        transform: translateY(850%);
    }

    60%,
    100% {
        transform: translateY(850%) scaleX(var(--scale));
    }
}

@keyframes close-bottom {
    0% {
        transform: translateY(850%) scaleX(var(--scale));
    }

    40% {
        transform: translateY(850%);
    }

    60%,
    100% {
        transform: translateY(0%) scaleX(1);
    }
}