nav {
    font-weight: 700;
    box-sizing: border-box;
    padding: 2.5rem 1.5rem;
    width: 100%;
    display: flex;
    justify-content: space-between;
    z-index: 999;
    letter-spacing: 0.25rem;
    position: fixed;
    top: 0;
    left: 0;
}

nav#cover_text {
    width: 100%;
}

nav .zh {
    letter-spacing: 0.5rem;
}

nav a {
    text-decoration: none;
}

#menu_icon {
    display: flex;
    flex-direction: column;
    justify-content: center;
    gap: 10px;
    height: 30px;
    width: 30px;
    cursor: pointer;
    z-index: 100;
}

#menu_icon>div {
    width: 30px;
    height: 1px;
    border-radius: 5px;
    -webkit-transition: all 0.5s ease;
    transition: all 0.5s ease;
    transform-origin: center;
    transform: rotateZ(0);
    -webkit-transform: rotateZ(0);
    background-color: var(--color-primary);
}

#menu_icon.open>div:nth-child(1) {
    transform: rotateZ(45deg) translateY(7px);
    -webkit-transform: rotateZ(45deg) translateY(7px);
}

#menu_icon.open>div:nth-child(2) {
    transform: rotateZ(-45deg) translateY(-7px);
    -webkit-transform: rotateZ(-45deg) translateY(-7px);
}

#menu_icon.open>div {
    background-color: #000;
}

.menu {
    display: flex;
    justify-content: center;
    align-items: center;
    width: 100vw;
    height: 100vh;
    -webkit-transition: opacity 0.5s ease;
    transition: opacity 0.5s ease;
    z-index: 49;
    position: fixed;
    top: 0;
    left: 0;
    background-color: var(--color-primary);
    z-index: 99;
    opacity: 0;
    pointer-events: none;
}

.menu.open {
    opacity: 1;
    pointer-events: auto;
}

.menu>div {
    height: 36vh;
    display: flex;
    flex-direction: column;
    justify-content: space-evenly;
    align-items: center;
}

.menu>div>* {
    color: #000;
    text-decoration: none;
}

@media screen and (min-width: 64rem) {
    nav {
        font-size: 1.53rem;
        padding: 9.07vh 10vw;
    }

    nav#cover_text {
        position: absolute;
        top: unset;
        bottom: 0;
    }

    .menu>div>* {
        font-size: 1.53rem;
    }
}