header {
    position: fixed;
    top: 8px;
    left: 0;
    width: 100vw;
    z-index: 999;
    transition: color .2s, background-color .2s;
}

nav {
    width: min-content; /* min(calc(100% - 7.25em), 900px); */
    height: 3em;
    margin: auto; /* auto 6em auto auto; */
    padding: 0 0 0 .25em;
    display: flex;
    flex-direction: row;
    gap: .8em;
    align-items: center;
    border-radius: 2em;
    backdrop-filter: blur(8px) brightness(110%);
    box-shadow: 0 1px 2px #0004;

    transition-property: background-color, color, backdrop-filter;
    transition-duration: .2s;

    img#header-icon {
        width: 2em;
        height: 2em;
        padding: .5em;
        transition: filter ease-out .1s;
    }
}

@media (prefers-color-scheme: dark) {
    nav {
        backdrop-filter: blur(8px) brightness(200%);

        img#header-icon {
            filter: invert();
        }
    }
}

@media screen and (max-width: 540px) {
    nav {
        width: calc(100vw - 2em);
        padding: 0 .25em;
    }
}

#header-home {
    display: flex;
    gap: .5em;
}

#header-links-toggle {
    width: 3em;
    height: 3em;
    margin-left: auto;
    margin-right: .5em;
    display: none;
    justify-content: center;
    align-items: center;
    transition: background-color .2s;
}

#header-links-toggle:hover {
    background-color: #fff2;
}

header ul#header-links {
    height: 100%;
    margin: 0;
    padding: 0;
    display: flex;
    flex-direction: row;
    align-items: center;
    gap: .5em;

    li {
        height: 100%;
        margin: 0 -.5em;
        list-style: none;

        &:last-of-type {
            margin-right: 0;

            a {
                padding-right: 1em;
            }
        }

        a, span {
            --colour: var(--links);

            height: 100%;
            min-width: 3em;
            padding: 0 1em;
            display: flex;
            justify-content: center;
            align-items: center;

            color: var(--colour);
            transition-property: color, background-color, box-shadow;
            transition-duration: .05s;
            transition-timing-function: ease-out;
            text-decoration: none;
        }

        span {
            color: #aaa;
            border-color: #aaa;
            cursor: default;
            text-decoration: none;
        }

        a {
            border-radius: 2em;

            &:hover, &.active {
                --bg-transparency: 90%;

                background-color: color-mix(
                    in srgb,
                    var(--colour),
                    transparent var(--bg-transparency)
                );
                text-decoration: none;

                &:active {
                    --bg-transparency: 75%;
                }
            }
        }
    }
}

@media screen and (max-width: 540px) {
    header {
        font-size: 14px;
    }

    div#header-text {
        flex-grow: 1;
    }

    a#header-links-toggle {
        display: flex;
    }

    header ul#header-links {
        position: fixed;
        left: -.75em;
        top: 3.5em;
        width: calc(100vw - 4em);
        height: fit-content;
        margin: 0 1em;
        padding: 1em;

        display: none;
        flex-direction: column;
        gap: 1rem;

        border-radius: 1em;
        box-shadow: 0 1px 2px #0004;
        background: var(--background);

        li {
            width: 100%;

            &:last-of-type {
                margin-right: -.5em;
            }

            a, span {
                margin: 0;
                display: block;
                font-size: 1em;
                text-align: center;
            }
        }	
    }

    header ul#header-links.open {
        display: flex;
    }
}

@keyframes list-item-fadein {
    from {
        opacity: 1;
        background: #fff8;
    }

    to {
        opacity: 1;
        background: transparent;
    }
}