.sidebar {
    position: fixed;
    top: var(--header-height);
    right: 0;
    bottom: 0;
    width: 100%;
    background: var(--secondary-color);
    padding: var(--space-3);
    z-index: 1;
    display: flex;
    flex-direction: column;
    gap: var(--space-4);
    overflow-y: auto;
    transform: translatex(100%);
    opacity: 0;
    transition: transform var(--transition-slow), opacity var(--transition-slow);
    box-shadow: -6px 0 16px var(--shadow-card), -2px 0 24px var(--glow-accent);
}

.sidebar.open {
    transform: translatex(0);
    opacity: 1;
}

.sidebar-nav {
    display: flex;
    flex-direction: column;
    gap: var(--space-2);
}

.sidebar-nav > a {
    padding: var(--space-2);
    border: 2px solid transparent;
    border-radius: var(--radius-sm);
    transition: all var(--transition-base);
}

.sidebar-nav > a:hover {
    border-color: var(--accent-color);
}

/* ===== mobile: category accordions (native <details>) ===== */
.nav-accordion {
    border-radius: var(--radius-sm);
}

.nav-accordion summary {
    padding: var(--space-2);
    border: 2px solid transparent;
    border-radius: var(--radius-sm);
    cursor: pointer;
    transition: all var(--transition-base);
    list-style: none;
}

.nav-accordion summary::-webkit-details-marker {
    display: none;
}

.nav-accordion summary:hover {
    border-color: var(--accent-color);
}

.nav-accordion summary::after {
    content: "▾";
    float: right;
    transition: transform var(--transition-base);
}

.nav-accordion[open] summary::after {
    transform: rotate(180deg);
}

.nav-accordion-links {
    display: flex;
    flex-direction: column;
    gap: var(--space-2);
    padding: var(--space-2) 0 0 var(--space-3);
}

.nav-accordion-links a {
    padding: var(--space-2);
    border: 2px solid transparent;
    border-radius: var(--radius-sm);
    transition: all var(--transition-base);
}

.nav-accordion-links a:hover {
    border-color: var(--accent-color);
}

.header-nav-links {
    display: flex;
    align-items: center;
    gap: var(--space-2);
}

.header-nav-links > a {
    padding: var(--space-2);
    border: 2px solid transparent;
    border-radius: var(--radius-sm);
    transition: all var(--transition-base);
}

.header-nav-links > a:hover {
    border-color: var(--accent-color);
}

/* ===== desktop: category dropdowns ===== */
.nav-category {
    position: relative;
}

.nav-category-toggle {
    padding: var(--space-2);
    border: 2px solid transparent;
    border-radius: var(--radius-sm);
    background: transparent;
    color: inherit;
    font: inherit;
    cursor: pointer;
    transition: all var(--transition-base);
}

.nav-category-toggle:hover {
    border-color: var(--accent-color);
}

.nav-category.open .nav-category-toggle {
    border-color: var(--accent-color);
}

.nav-category-menu {
    position: absolute;
    top: calc(100% + var(--space-2));
    left: 0;
    display: none;
    flex-direction: column;
    gap: var(--space-1);
    min-width: 200px;
    padding: var(--space-2);
    background: var(--secondary-color);
    border-radius: var(--radius-sm);
    box-shadow: 0 6px 16px var(--shadow-card), 0 2px 24px var(--glow-accent);
    z-index: 2;
}

.nav-category.open .nav-category-menu {
    display: flex;
}

.nav-category-menu a {
    padding: var(--space-2);
    border: 2px solid transparent;
    border-radius: var(--radius-sm);
    white-space: nowrap;
    transition: all var(--transition-base);
}

.nav-category-menu a:hover {
    border-color: var(--accent-color);
}

.nav-desktop-only {
    display: none;
}