/* App Shell Layout */
.app-shell {
    display: flex;
    height: 100vh;
    overflow: hidden;
}

.app-shell--no-sidebar {
    display: flex;
    flex-direction: column;
    height: 100vh;
}

/* Sidebar */
.sidebar {
    width: var(--sidebar-width);
    background: var(--sidebar-bg);
    color: var(--sidebar-text);
    display: flex;
    flex-direction: column;
    transition: width var(--transition-normal);
    overflow-y: auto;
    overflow-x: hidden;
    flex-shrink: 0;
    z-index: 20;
}

.sidebar--collapsed {
    width: var(--sidebar-collapsed-width);
}

.sidebar__logo {
    height: var(--topbar-height);
    display: flex;
    align-items: center;
    padding: 0 var(--space-md);
    border-bottom: 1px solid rgba(255, 255, 255, 0.1);
    font-size: var(--font-size-lg);
    font-weight: 700;
    color: var(--sidebar-text-active);
    white-space: nowrap;
    overflow: hidden;
}

.sidebar__nav {
    flex: 1;
    padding: var(--space-sm) 0;
}

.sidebar__item {
    display: flex;
    align-items: center;
    padding: var(--space-sm) var(--space-md);
    color: var(--sidebar-text);
    cursor: pointer;
    transition: all var(--transition-fast);
    border-left: 3px solid transparent;
    gap: var(--space-sm);
    white-space: nowrap;
    overflow: hidden;
}

.sidebar__item:hover {
    background: var(--sidebar-hover);
    color: var(--sidebar-text-active);
}

.sidebar__item--active {
    background: rgba(37, 99, 235, 0.15);
    color: var(--sidebar-text-active);
    border-left-color: var(--sidebar-active);
}

.sidebar__icon {
    width: 20px;
    height: 20px;
    flex-shrink: 0;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: var(--font-size-lg);
}

.sidebar__label {
    font-size: var(--font-size-sm);
}

.sidebar--collapsed .sidebar__label {
    display: none;
}

.sidebar__footer {
    padding: var(--space-md);
    border-top: 1px solid rgba(255, 255, 255, 0.1);
}

/* Main Content Area */
.main-area {
    flex: 1;
    display: flex;
    flex-direction: column;
    overflow: hidden;
    min-width: 0;
}

/* TopBar */
.topbar {
    height: var(--topbar-height);
    background: var(--topbar-bg);
    border-bottom: 1px solid var(--topbar-border);
    display: flex;
    align-items: center;
    padding: 0 var(--space-lg);
    gap: var(--space-md);
    flex-shrink: 0;
    z-index: 10;
}

.topbar__left {
    display: flex;
    align-items: center;
    gap: var(--space-md);
}

.topbar__hamburger {
    display: none;
    padding: var(--space-sm);
    color: var(--color-text);
    font-size: var(--font-size-xl);
}

.topbar__breadcrumbs {
    display: flex;
    align-items: center;
    gap: var(--space-xs);
    font-size: var(--font-size-sm);
    color: var(--color-text-secondary);
}

.topbar__breadcrumb-sep {
    color: var(--color-text-muted);
}

.topbar__breadcrumb--active {
    color: var(--color-text);
    font-weight: 500;
}

.topbar__right {
    margin-left: auto;
    display: flex;
    align-items: center;
    gap: var(--space-md);
}

.topbar__theme-toggle {
    padding: var(--space-sm);
    color: var(--color-text-secondary);
    border-radius: var(--radius-md);
    transition: all var(--transition-fast);
}

.topbar__theme-toggle:hover {
    background: var(--color-bg-tertiary);
    color: var(--color-text);
}

.topbar__user {
    display: flex;
    align-items: center;
    gap: var(--space-sm);
    padding: var(--space-xs) var(--space-sm);
    border-radius: var(--radius-md);
    cursor: pointer;
    transition: background var(--transition-fast);
}

.topbar__user:hover {
    background: var(--color-bg-tertiary);
}

.topbar__avatar {
    width: 32px;
    height: 32px;
    border-radius: var(--radius-full);
    background: var(--color-primary);
    color: var(--color-text-inverse);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: var(--font-size-sm);
    font-weight: 600;
}

.topbar__user-name {
    font-size: var(--font-size-sm);
    font-weight: 500;
}

/* Content Area */
.content {
    flex: 1;
    overflow-y: auto;
    padding: var(--space-lg);
    background: var(--color-bg);
}

.content__header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    margin-bottom: var(--space-lg);
}

.content__title {
    font-size: var(--font-size-2xl);
    font-weight: 700;
    color: var(--color-text);
}

/* Page layouts */
.page-grid {
    display: grid;
    gap: var(--space-lg);
}

.page-grid--2col {
    grid-template-columns: repeat(2, 1fr);
}

.page-grid--3col {
    grid-template-columns: repeat(3, 1fr);
}

.page-grid--4col {
    grid-template-columns: repeat(4, 1fr);
}

.page-grid--sidebar {
    grid-template-columns: 1fr 320px;
}

/* Responsive */
@media (max-width: 1200px) {
    .sidebar {
        width: var(--sidebar-collapsed-width);
    }
    .sidebar .sidebar__label {
        display: none;
    }
    .page-grid--4col {
        grid-template-columns: repeat(2, 1fr);
    }
}

@media (max-width: 768px) {
    .sidebar {
        position: fixed;
        left: -100%;
        top: 0;
        height: 100%;
        width: var(--sidebar-width);
        z-index: 100;
        transition: left var(--transition-normal);
    }
    .sidebar--open {
        left: 0;
    }
    .sidebar .sidebar__label {
        display: inline;
    }
    .topbar__hamburger {
        display: flex;
    }
    .page-grid--2col,
    .page-grid--3col,
    .page-grid--4col {
        grid-template-columns: 1fr;
    }
    .page-grid--sidebar {
        grid-template-columns: 1fr;
    }
    .content {
        padding: var(--space-md);
    }
}

/* Overlay for mobile sidebar */
.sidebar-overlay {
    display: none;
    position: fixed;
    inset: 0;
    background: rgba(0, 0, 0, 0.5);
    z-index: 99;
}

.sidebar-overlay--visible {
    display: block;
}