header {
    width: 100%;
}

header nav {
    display: flex;
    width: fit-content;
    max-width: 94vw;
    padding: 0.3rem 1.4rem;
    background-color: var(--bg-color);
    align-items: center;
    justify-content: center;
    gap: 0.6rem;
    position: fixed;
    left: 50%;
    bottom: -100%;
    z-index: 99;
    border-radius: 20px 20px 0 0;
    transform: translate(-50%, 0);
    transition: bottom 2s ease, transform 1s ease;
}

header nav.active {
    bottom: 0;
}

header nav.scroll {
    transform: translate(-50%, 100%);
}

header nav a,
header nav button {
    display: flex;
    align-items: center;
    justify-content: center;
    flex-direction: column;
    gap: 0.1rem;
    position: relative;
    isolation: isolate;
    overflow: hidden;
    width: 4rem;
    height: 3rem;
    color: var(--primary-font-color);
    border-radius: 10px;
    transition: color 0.35s ease, transform 0.35s ease, background-color 0.35s ease;
}

header nav a::before,
header nav button::before {
    content: '';
    position: absolute;
    inset: 0.2rem;
    z-index: -1;
    border-radius: 8px;
    background: var(--accent-color);
    transform: translateY(115%) scale(0.7);
    opacity: 0;
    transition: transform 0.35s cubic-bezier(0.22, 1, 0.36, 1), opacity 0.25s ease;
}

header nav a i,
header nav button i {
    font-size: 1.2rem;
    transition: transform 0.35s cubic-bezier(0.22, 1, 0.36, 1), color 0.35s ease;
}

header nav a span,
header nav button span {
    font-size: 0.6rem;
    transition: transform 0.35s ease;
}

header nav a:hover,
header nav a:focus-visible,
header nav button:hover,
header nav button:focus-visible {
    color: #fff;
    transform: translateY(-0.25rem);
}

header nav a:hover::before,
header nav a:focus-visible::before,
header nav button:hover::before,
header nav button:focus-visible::before {
    transform: translateY(0) scale(1);
    opacity: 1;
}

header nav a:hover i,
header nav a:focus-visible i,
header nav button:hover i,
header nav button:focus-visible i {
    color: #ffcf86;
    transform: translateY(-0.12rem) scale(1.14) rotate(-6deg);
}

header nav a:hover span,
header nav a:focus-visible span,
header nav button:hover span,
header nav button:focus-visible span {
    transform: translateY(-0.04rem);
}

header nav button {
    background: none;
    border: none;
    font-family: inherit;
    color: var(--accent-color);
    cursor: pointer;
}

@media (prefers-reduced-motion: reduce) {
    header nav a,
    header nav button,
    header nav a::before,
    header nav button::before,
    header nav a i,
    header nav button i,
    header nav a span,
    header nav button span {
        transition: none;
    }
}