header {
    z-index: 3;
    position: relative;
    display: flex;
    justify-content: space-between;
    gap: var(--space-4);
    border-bottom: var(--border);
    font-size: var(--text-sm);
    padding: 1px var(--space-1);
    user-select: none;
}

.navbar {
    display: flex;
    align-items: center;
    gap: 2px;
}

.nav-item {
    padding: 2px var(--space-2);
    border-radius: var(--radius-sm);
    cursor: pointer;
    font-weight: var(--font-weight-strong);
}

.nav-item:hover,
.keyboard .nav-item:focus {
    background-color: var(--color-fill);
}

.nav-item:active,
.dropdown.active .dropdown-button {
    background-color: var(--color-fill-strong);
}

.dropdown {
    position: relative;
}

.dropdown-menu {
    z-index: 1;
    position: absolute;
    top: calc(100% + var(--space-2));
    width: max-content;
    padding: var(--space-1);
    background-color: var(--color-surface);
    border: var(--border);
    border-radius: var(--radius-md);
    box-shadow: var(--shadow-md);
    display: none;
    max-height: var(--menu-height);
    overflow-y: auto;
    overscroll-behavior: contain;
}

.dropdown.active .dropdown-menu {
    display: block;
}

.dropdown-item {
    display: flex;
    justify-content: space-between;
    align-items: center;
    gap: var(--space-7);
    width: 100%;
    height: var(--item-height);
    padding: 0 var(--space-3);
    border-radius: var(--radius-sm);
    cursor: pointer;
}

.dropdown-item > kbd {
    line-height: 1;
}

.dropdown-item:hover,
.keyboard .dropdown-item:focus {
    background-color: var(--color-fill);
}

.dropdown-item:active {
    background-color: var(--color-fill-strong);
}

.dropdown-item:disabled {
    opacity: var(--opacity-disabled);
    cursor: default;
}

.dropdown-item:disabled:hover {
    background-color: transparent;
}

.filename {
    min-width: 0;
    overflow: hidden;
    padding: 0 var(--space-2);
    font-size: var(--text-xs);
    color: var(--color-text-muted);
    white-space: nowrap;
    text-overflow: ellipsis;
    align-content: center;
}

.spinner {
    height: 1rem;
    width: 1rem;
    border: 2px solid transparent;
    border-top-color: var(--color-accent);
    border-right-color: var(--color-accent);
    border-radius: var(--radius-full);
    margin-left: var(--space-4);
    animation: spinner 1s linear infinite;
}

@keyframes spinner {
    to {
        transform: rotate(360deg);
    }
}

/* Reduced motion: it does not turn; it fades in and out (still busy) */
@media (prefers-reduced-motion: reduce) {
    .spinner {
        animation: spinner-fade 1s ease-in-out infinite alternate;
    }
}

@keyframes spinner-fade {
    to {
        opacity: 0.3;
    }
}

@media (pointer: coarse) {
    .nav-item {
        padding: var(--space-2) var(--space-3);
    }
}

@media (max-width: 560px) {
    .dropdown {
        position: static;
    }

    .dropdown-menu {
        left: var(--space-1);
        max-width: calc(100vw - 2 * var(--space-1));
        min-width: 14rem;
    }

    .dropdown-item > span {
        overflow: hidden;
        white-space: nowrap;
        text-overflow: ellipsis;
    }

    .dropdown-item > kbd {
        display: none;
    }
}