header.css

.header{
    display: flex;
    align-items: center;
    z-index: 2;
}
.button-open{
    justify-self: flex-start;
}
.sidebar{
    width: var(--sidebar);
    position: fixed;
    top: 0;
    bottom: 0;
    left: -100%;
    background-color: var(--bg-base);
    transition: all 300ms var(--transition-2);
}

.sidebar:target {
    left: 0;
    transition: all 300ms var(--transition-2);
}

.button-close{
    display: block;
    text-align: end;
}

/* .sidebar__list{
} */

.sidebar__item,
.button-close {
    padding: var(--space-3) var(--space-4);
}

.sidebar__link{
    color: var(--text-base);
}


@media screen and (min-width: 800px) {
    .button-open,
    .button-close {
        display: none;
    }
    .sidebar__item .button {
        display: inline-block;
    }
    .sidebar {
        position: static;
        left: 0;
        width: 100%;
        height: 100%;
        background-color: var(--transparent);
    }
    .sidebar__list {
        display: inline-flex;
        align-items: center;
        justify-content: flex-end;
        width: 100%;
        height: 100%;
    }
}