/* Sidebar navigation (NavMenu) - global fallback for static hosting */
.sidebar {
    background: var(--sidebar-bg);
    border-right: 1px solid var(--sidebar-border);
    width: 260px;
    height: 100vh;
    position: sticky;
    top: 0;
    display: flex;
    flex-direction: column;
    transition: width 0.2s ease;
    z-index: 80;
}

.sidebar.collapsed {
    width: 72px;
}

.sidebar-header {
    padding: 0.6rem 0.75rem 0.5rem;
}

.subject-switcher {
    position: relative;
}

.subject-switcher-button {
    width: 100%;
    display: flex;
    align-items: center;
    gap: 0.6rem;
    padding: 0.55rem 0.65rem;
    border-radius: 10px;
    border: 1px solid var(--sidebar-surface-border);
    background: var(--sidebar-surface);
    color: var(--text-primary);
    font-size: 0.86rem;
    cursor: pointer;
    text-align: left;
    transition: border-color 0.2s ease, box-shadow 0.2s ease;
}

.subject-switcher-button:hover {
    border-color: var(--border-strong);
    box-shadow: var(--shadow-soft);
}

.subject-avatar {
    width: 28px;
    height: 28px;
    border-radius: 8px;
    background: var(--sidebar-avatar-bg);
    color: var(--sidebar-avatar-fg);
    display: inline-flex;
    align-items: center;
    justify-content: center;
    font-weight: 600;
    font-size: 0.82rem;
    flex-shrink: 0;
}

.subject-avatar img {
    width: 100%;
    height: 100%;
    object-fit: cover;
    border-radius: 8px;
}

.subject-name {
    flex: 1;
    font-weight: 600;
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
}

.subject-caret {
    width: 16px;
    height: 16px;
    color: var(--sidebar-caret);
    flex-shrink: 0;
}

.subject-menu {
    position: absolute;
    top: calc(100% + 0.5rem);
    left: 0;
    width: 100%;
    min-width: 220px;
    background: var(--sidebar-surface);
    border: 1px solid var(--sidebar-surface-border);
    border-radius: 12px;
    padding: 0.35rem;
    box-shadow: var(--shadow-popover);
    display: flex;
    flex-direction: column;
    gap: 0.25rem;
    z-index: 60;
}

.subject-menu-status {
    padding: 0.6rem 0.7rem;
    font-size: 0.85rem;
    color: var(--text-muted);
}

.subject-menu-item {
    border: none;
    background: transparent;
    text-align: left;
    padding: 0.5rem 0.7rem;
    border-radius: 8px;
    font-size: 0.85rem;
    color: var(--text-primary);
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: flex-start;
    gap: 0.5rem;
}

.subject-menu-info {
    display: flex;
    align-items: center;
    gap: 0.6rem;
    min-width: 0;
}

.subject-menu-avatar {
    width: 24px;
    height: 24px;
    border-radius: 8px;
    background: var(--sidebar-avatar-bg);
    color: var(--sidebar-avatar-fg);
    display: inline-flex;
    align-items: center;
    justify-content: center;
    font-weight: 600;
    font-size: 0.75rem;
    flex-shrink: 0;
    overflow: hidden;
}

.subject-menu-avatar img {
    width: 100%;
    height: 100%;
    object-fit: cover;
}

.subject-menu-name {
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
}

.subject-menu-item:hover {
    background: var(--sidebar-hover-bg);
}

.subject-menu-item.active {
    background: var(--sidebar-active-bg);
    font-weight: 600;
}

.subject-menu-footer {
    border-top: 1px solid var(--sidebar-surface-border);
    padding-top: 0.35rem;
}

.subject-menu-link {
    display: block;
    text-decoration: none;
    color: var(--text-secondary);
    padding: 0.45rem 0.7rem;
    border-radius: 8px;
    font-size: 0.82rem;
}

.subject-menu-link:hover {
    background: var(--sidebar-hover-bg);
    color: var(--text-primary);
}

.nav-sections {
    flex: 1;
    overflow-y: auto;
    padding-bottom: 0.75rem;
}

.nav-section {
    display: flex;
    flex-direction: column;
    gap: 0.2rem;
    margin-top: 0.35rem;
}

.nav-section-title {
    font-size: 0.65rem;
    text-transform: uppercase;
    letter-spacing: 0.08em;
    color: var(--text-subtle);
    padding: 0.5rem 0.95rem 0.2rem;
}

.nav-section-title.subject-title {
    text-transform: none;
    letter-spacing: 0;
    font-size: 0.75rem;
    font-weight: 600;
    color: var(--text-muted);
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
}

.sidebar .nav-link {
    position: relative;
    display: flex;
    align-items: center;
    gap: 0.65rem;
    padding: 0.55rem 0.8rem;
    margin: 0 0.5rem;
    border-radius: 10px;
    color: var(--text-primary);
    text-decoration: none;
    font-size: 0.8rem;
    line-height: 1.4;
    transition: background-color 0.2s ease, color 0.2s ease;
}

.sidebar button.nav-link {
    background: transparent;
    border: none;
    width: 100%;
    text-align: left;
    font-family: inherit;
    appearance: none;
}

.sidebar .nav-link:visited {
    color: var(--text-primary);
}

.sidebar .nav-link:hover {
    background: var(--sidebar-hover-bg);
    color: var(--text-primary);
}

.sidebar .nav-link.active {
    background: var(--sidebar-active-bg);
    font-weight: 600;
    color: var(--text-primary);
    box-shadow: inset 2px 0 0 var(--sidebar-active-indicator);
}

.nav-icon {
    width: 1.25rem;
    height: 1.25rem;
    color: var(--sidebar-icon);
    flex-shrink: 0;
}

.sidebar .nav-link.active .nav-icon {
    color: var(--sidebar-icon-active);
}

.nav-badge {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    min-width: 1.25rem;
    height: 1.25rem;
    padding: 0 0.35rem;
    border-radius: 999px;
    font-size: 0.7rem;
    font-weight: 700;
    background: var(--text-primary);
    color: var(--bg-primary);
    line-height: 1;
    margin-left: auto;
}

.settings-group {
    margin-top: 0.2rem;
}

.settings-row {
    display: flex;
    align-items: center;
    gap: 0.25rem;
    margin: 0 0.5rem;
}

.settings-row .nav-link {
    margin: 0;
}

.settings-link {
    flex: 1;
    margin: 0;
}

.settings-expander {
    width: 32px;
    height: 32px;
    border-radius: 8px;
    border: 1px solid transparent;
    background: transparent;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    color: var(--text-muted);
    transition: background-color 0.2s ease, color 0.2s ease;
}

.settings-expander:hover {
    background: var(--sidebar-hover-bg);
    color: var(--text-primary);
}

.settings-expander.expanded .nav-caret {
    transform: rotate(180deg);
}

.nav-caret {
    width: 1rem;
    height: 1rem;
    transition: transform 0.26s cubic-bezier(0.2, 0, 0, 1);
}

.settings-submenu {
    display: flex;
    flex-direction: column;
    gap: 0.2rem;
    margin: 0.35rem 0 0.4rem 1.25rem;
    padding-left: 0.5rem;
    border-left: 1px solid var(--sidebar-border);
    max-height: 0;
    opacity: 0;
    transform: translateY(-4px);
    overflow: hidden;
    pointer-events: none;
    visibility: hidden;
    transition: max-height 0.26s cubic-bezier(0.2, 0, 0, 1), opacity 0.26s ease, transform 0.26s ease, visibility 0s linear 0.26s;
}

.settings-submenu.open {
    max-height: 320px;
    opacity: 1;
    transform: translateY(0);
    pointer-events: auto;
    visibility: visible;
    transition: max-height 0.26s cubic-bezier(0.2, 0, 0, 1), opacity 0.26s ease, transform 0.26s ease;
}

.settings-submenu.collapsed {
    max-height: 0;
    opacity: 0;
    transform: translateY(-4px);
    pointer-events: none;
    visibility: hidden;
}

@media (prefers-reduced-motion: reduce) {
    .settings-submenu,
    .settings-submenu.open {
        transition: none;
        transform: none;
    }
}

.settings-submenu .nav-link {
    margin: 0;
    padding: 0.45rem 0.6rem;
    font-size: 0.76rem;
    border-radius: 8px;
}

.nav-subicon {
    width: 1.05rem;
    height: 1.05rem;
    color: var(--text-subtle);
    flex-shrink: 0;
}

.sidebar .nav-link.active .nav-subicon {
    color: var(--sidebar-icon-active);
}

.sidebar-footer {
    padding: 0.75rem;
    border-top: 1px solid var(--sidebar-border);
}

.sidebar-toggle {
    width: 100%;
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    border-radius: 10px;
    border: 1px solid var(--sidebar-surface-border);
    background: var(--sidebar-surface);
    padding: 0.45rem 0.7rem;
    color: var(--text-secondary);
    font-size: 0.82rem;
    cursor: pointer;
    transition: background-color 0.2s ease, color 0.2s ease;
}

.sidebar-toggle:hover {
    background: var(--sidebar-hover-bg);
    color: var(--text-primary);
}

.sidebar-toggle svg {
    width: 16px;
    height: 16px;
    transition: transform 0.2s ease;
}

.sidebar.collapsed .subject-name,
.sidebar.collapsed .subject-caret,
.sidebar.collapsed .nav-text,
.sidebar.collapsed .nav-section-title,
.sidebar.collapsed .sidebar-toggle span {
    display: none;
}

.sidebar.collapsed .subject-switcher-button {
    justify-content: center;
    padding: 0.5rem;
}

.sidebar.collapsed .nav-link {
    justify-content: center;
    margin: 0.15rem auto;
    width: 44px;
    padding: 0.55rem;
}

.sidebar.collapsed .nav-section + .nav-section {
    margin-top: 0.7rem;
    padding-top: 0.7rem;
    border-top: 1px solid color-mix(in srgb, var(--sidebar-border) 70%, transparent);
}

.sidebar.collapsed .settings-group {
    position: relative;
}

.sidebar.collapsed .settings-row {
    margin: 0;
}

.sidebar.collapsed .settings-expander {
    display: none;
}

.sidebar.collapsed .settings-submenu {
    margin-left: 0;
    padding-left: 0;
    border-left: none;
    max-height: 0;
    opacity: 0;
    pointer-events: none;
    visibility: hidden;
    transform: none;
}

.collapsed-submenu-backdrop {
    position: fixed;
    inset: 0 0 0 72px;
    border: none;
    margin: 0;
    padding: 0;
    width: calc(100% - 72px);
    background: transparent;
    z-index: var(--z-overlay-sidebar-flyout-backdrop, 165);
}

.collapsed-submenu-layer {
    position: fixed;
    inset: 0;
    pointer-events: none;
    z-index: var(--z-overlay-sidebar-flyout, 170);
}

.collapsed-submenu-layer .settings-submenu.as-popover {
    position: fixed;
    top: 0;
    left: calc(72px + 0.2rem);
    width: min(250px, calc(100vw - 88px));
    max-height: min(420px, calc(100vh - 16px));
    margin: 0;
    padding: 0.35rem;
    border: 1px solid var(--sidebar-surface-border);
    border-radius: 12px;
    background: var(--sidebar-surface);
    box-shadow: var(--shadow-popover);
    pointer-events: auto;
    overflow-y: auto;
    transform: none;
    opacity: 1;
    visibility: visible;
}

.collapsed-submenu-layer .settings-submenu.as-popover::before {
    content: "";
    position: absolute;
    top: 0;
    bottom: 0;
    left: -0.65rem;
    width: 0.65rem;
}

.collapsed-submenu-layer .settings-submenu.as-popover .nav-link {
    width: 100%;
    margin: 0;
    padding: 0.45rem 0.6rem;
    justify-content: flex-start;
    color: var(--text-primary);
    text-decoration: none;
    font-size: 0.8rem;
    line-height: 1.4;
}

.collapsed-submenu-layer .settings-submenu.as-popover .nav-text {
    display: inline;
}

.collapsed-submenu-layer .settings-submenu.as-popover .nav-link:hover {
    background: var(--sidebar-hover-bg);
    color: var(--text-primary);
}

.collapsed-submenu-layer .settings-submenu.as-popover .nav-link.active {
    background: var(--sidebar-active-bg);
    font-weight: 600;
    color: var(--text-primary);
    box-shadow: inset 2px 0 0 var(--sidebar-active-indicator);
}

.collapsed-submenu-layer .settings-submenu.as-popover .nav-subicon {
    color: var(--text-subtle);
}

.collapsed-submenu-layer .settings-submenu.as-popover .nav-link.active .nav-subicon {
    color: var(--sidebar-icon-active);
}

.sidebar.collapsed .sidebar-toggle svg {
    transform: rotate(180deg);
}

@media (max-width: 640px) {
    .sidebar {
        width: 100%;
        height: auto;
        position: static;
    }

    .sidebar.collapsed {
        width: 100%;
    }

    .sidebar.collapsed .nav-text,
    .sidebar.collapsed .nav-section-title {
        display: inline;
    }

    .sidebar.collapsed .nav-link {
        width: auto;
        margin: 0 0.5rem;
        justify-content: flex-start;
    }

    .sidebar-toggle span {
        display: inline;
    }
}