/* --- Navigation Component --- */
:root {
    --neutral-layer-1: #ffffff;
    --neutral-layer-2: #f8f8f8;
    --accent-color: #0078d4;
    --sidebar-width: 280px;
    --sidebar-transition-duration: 0.3s;
    --font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
}

.nav-header {
    padding: 0 20px;
    text-align: center;
    margin-bottom: 20px;
}

.nav-header fluent-avatar {
    width: 80px;
    height: 80px;
    margin-bottom: 10px;
}

.profile-avatar {
    width: 120px;
    height: 120px;
    border-radius: 50%;
    object-fit: cover;
    margin-bottom: 15px;
    border: 4px solid var(--neutral-layer-1);
    box-shadow: 0 4px 15px rgba(0, 120, 212, 0.2);
}

.nav-header h3 {
    margin: 0;
    font-family: var(--font-family);
    font-weight: 600;
    border-bottom: none;
}

.nav-links {
    list-style: none;
    padding: 0;
    margin: 0;
    overflow-y: auto;
    flex-grow: 1;
    min-height: 0;
    max-height: 100%;
    scrollbar-gutter: stable;
    scrollbar-width: thin;
    scrollbar-color: rgba(0, 0, 0, 0.2) transparent;
}

.nav-links .return-img {
    width: 16px;
    height: 16px;
    transform: rotate(180deg);
    filter: invert(40%);
    transition: filter 0.2s ease;
}

.nav-links::-webkit-scrollbar {
    width: 10px;
}

.nav-links::-webkit-scrollbar-track {
    background: transparent;
}

.nav-links::-webkit-scrollbar-thumb {
    background: linear-gradient(180deg, rgba(0, 120, 212, 0.6), rgba(0, 120, 212, 0.3));
    border-radius: 999px;
}

.nav-links::-webkit-scrollbar-thumb:hover {
    background: linear-gradient(180deg, rgba(0, 120, 212, 0.8), rgba(0, 120, 212, 0.5));
}

.nav-links>li {
    font-family: var(--font-family);
    display: flex;
    flex-wrap: wrap;
    align-items: center;
    position: relative;
}

.nav-item {
    flex: 1 1 auto;
    min-width: 0;
    display: flex;
    align-items: center;
    gap: 15px;
    padding: 12px 25px;
    text-decoration: none;
    color: #333;
    transition: background-color 0.2s ease-in-out;
}

.nav-item:hover {
    background-color: #f0f0f0;
}

.nav-item.active {
    background-color: #eaf3fb;
    border-left-color: var(--accent-color);
    font-weight: 600;
    color: var(--accent-color);
}

.nav-item-parent.active {
    border-left: 4px solid #0078d4;
}

.nav-submenu {
    width: 100%;
    list-style: none;
    margin: 0;
    padding-left: 12px;
    max-height: 0;
    overflow: hidden;
    transition: max-height 0.4s ease, opacity 0.6s ease;
    opacity: 0;
}

.nav-item-parent[aria-expanded="true"]~.nav-submenu,
.nav-item-parent:hover~.nav-submenu,
.nav-toggle-btn:hover~.nav-submenu,
.nav-submenu:hover {
    max-height: 1000px;
    opacity: 1;
}

.nav-submenu .nav-item {
    padding: 8px 25px;
    padding-left: 36px;
    font-size: 0.95rem;
    color: #444;
}

.nav-submenu .nav-submenu {
    padding-left: 12px;
}

.nav-submenu-headings .nav-item {
    padding-left: 48px;
    font-size: 0.9rem;
    color: #555;
}

.nav-submenu-empty {
    padding: 6px 25px 6px 48px;
    font-size: 0.9rem;
    color: #888;
}

.nav-toggle-btn {
    background: transparent;
    border: none;
    width: 36px;
    height: 36px;
    display: flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    border-radius: 4px;
    margin-right: 8px;
}

.nav-toggle-btn:hover {
    background-color: rgba(0, 0, 0, 0.05);
}

.nav-toggle-btn img,
.nav-toggle-btn svg {
    width: 16px;
    height: 16px;
    color: #666;
    transition: transform 0.2s ease;
}

.nav-toggle-btn.expanded img,
.nav-item-parent[aria-expanded="true"]+.nav-toggle-btn img {
    transform: rotate(90deg);
}

/* --- Sidebar Shell (layout + overlay) --- */
.sidebar {
    width: var(--sidebar-width);
    height: 100vh;
    background-color: var(--neutral-layer-1);
    border-right: 1px solid #e0e0e0;
    padding: 20px 0;
    box-sizing: border-box;
    display: flex;
    flex-direction: column;
    position: fixed;
    top: 0;
    left: 0;
    z-index: 1000;
    transform: translateX(-100%);
    transition: transform var(--sidebar-transition-duration) ease-in-out;
}

.sidebar.open {
    transform: translateX(0);
    box-shadow: 0 0 20px rgba(0, 0, 0, 0.1);
}

#sidebar-toggle {
    position: fixed;
    top: 15px;
    left: 15px;
    z-index: 1001;
}

.sidebar-overlay {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background-color: rgba(0, 0, 0, 0.4);
    z-index: 999;
    opacity: 0;
    pointer-events: none;
    transition: opacity var(--sidebar-transition-duration) ease-in-out;
}

.sidebar-overlay.visible {
    opacity: 1;
    pointer-events: auto;
}