.sidebar-collapse-toggle {
    display: inline-grid;
    place-items: center;
    width: 28px;
    height: 28px;
    flex: 0 0 28px;
    padding: 0;
    border: 1px solid var(--zn-border-soft);
    border-radius: 8px;
    background: transparent;
    color: var(--zn-text-muted);
    cursor: pointer;
    transition: color 0.14s ease, background 0.14s ease, border-color 0.14s ease;
}

.sidebar-collapse-toggle:hover,
.sidebar-collapse-toggle:focus-visible {
    border-color: var(--zn-border-strong);
    background: var(--zn-bg-surface-hover);
    color: var(--zn-text-primary);
}

.sidebar-collapse-toggle:focus-visible {
    outline: 2px solid var(--zn-accent);
    outline-offset: 2px;
}

.sidebar-collapse-chevron {
    width: 8px;
    height: 8px;
    border-right: 2px solid currentColor;
    border-bottom: 2px solid currentColor;
    transform: rotate(135deg);
    transition: transform 0.14s ease;
}

@media (prefers-reduced-motion: reduce) {
    .sidebar-collapse-toggle,
    .sidebar-collapse-chevron {
        transition: none !important;
    }
}