/* ============================================================
   TFA Lernapp - Layout Styles
   ============================================================ */

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

/* ---- Sidebar (Desktop) ---- */
.sidebar {
    width: var(--sidebar-width);
    background: var(--bg-secondary);
    border-right: 1px solid var(--border-color);
    display: flex;
    flex-direction: column;
    position: fixed;
    top: 0;
    left: 0;
    bottom: 0;
    z-index: var(--z-sticky);
    transition: transform var(--transition-base);
}

.sidebar-header {
    padding: var(--space-lg);
    border-bottom: 1px solid var(--border-color);
    display: flex;
    align-items: center;
    gap: var(--space-md);
}

.sidebar-logo {
    width: 40px;
    height: 40px;
    background: linear-gradient(135deg, var(--primary-500), var(--success-500));
    border-radius: var(--radius-lg);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.2rem;
}

.sidebar-brand {
    font-size: var(--text-lg);
    font-weight: 800;
    background: linear-gradient(135deg, var(--primary-400), var(--success-400));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.sidebar-nav {
    flex: 1;
    padding: var(--space-md);
    overflow-y: auto;
}

.nav-section-title {
    font-size: var(--text-xs);
    font-weight: 700;
    text-transform: uppercase;
    letter-spacing: 0.05em;
    color: var(--text-tertiary);
    padding: var(--space-sm) var(--space-md);
    margin-top: var(--space-md);
}

.nav-item {
    display: flex;
    align-items: center;
    gap: var(--space-md);
    padding: 0.625rem var(--space-md);
    border-radius: var(--radius-lg);
    color: var(--text-secondary);
    font-size: var(--text-sm);
    font-weight: 500;
    cursor: pointer;
    transition: all var(--transition-fast);
    border: none;
    background: none;
    width: 100%;
    text-align: left;
    font-family: var(--font-family);
}

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

.nav-item.active {
    background: rgba(99, 102, 241, 0.12);
    color: var(--primary-400);
}

.nav-item-icon {
    width: 20px;
    height: 20px;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.1rem;
}

.nav-item-badge {
    margin-left: auto;
    background: var(--primary-600);
    color: white;
    font-size: 10px;
    font-weight: 700;
    padding: 2px 6px;
    border-radius: var(--radius-full);
    min-width: 20px;
    text-align: center;
}

.sidebar-footer {
    padding: var(--space-md);
    border-top: 1px solid var(--border-color);
}

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

.sidebar-user:hover {
    background: var(--bg-tertiary);
}

.sidebar-user-info {
    flex: 1;
    min-width: 0;
}

.sidebar-user-name {
    font-size: var(--text-sm);
    font-weight: 600;
    color: var(--text-primary);
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
}

.sidebar-user-role {
    font-size: var(--text-xs);
    color: var(--text-tertiary);
}

/* ---- Main Content ---- */
.main-content {
    flex: 1;
    margin-left: var(--sidebar-width);
    min-height: 100vh;
}

.page-container {
    max-width: var(--container-max);
    margin: 0 auto;
    padding: var(--space-xl) var(--space-xl);
}

.page-header {
    margin-bottom: var(--space-2xl);
}

.page-title {
    font-size: var(--text-3xl);
    font-weight: 800;
    margin-bottom: var(--space-xs);
}

.page-subtitle {
    font-size: var(--text-base);
    color: var(--text-secondary);
}

/* ---- Mobile Header ---- */
.mobile-header {
    display: none;
    position: sticky;
    top: 0;
    z-index: var(--z-sticky);
    background: var(--bg-secondary);
    border-bottom: 1px solid var(--border-color);
    padding: var(--space-md) var(--space-lg);
    backdrop-filter: blur(12px);
    align-items: center;
    justify-content: space-between;
}

.mobile-menu-btn {
    width: 40px;
    height: 40px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: transparent;
    border: none;
    color: var(--text-primary);
    cursor: pointer;
    border-radius: var(--radius-md);
    font-size: 1.5rem;
}

.mobile-nav-overlay {
    display: none;
    position: fixed;
    inset: 0;
    background: rgba(0,0,0,0.5);
    z-index: calc(var(--z-sticky) - 1);
}

.mobile-nav-overlay.active {
    display: block;
}

/* ---- Grid Layouts ---- */
.grid-2 {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: var(--space-md);
}

.grid-3 {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: var(--space-md);
}

.grid-4 {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: var(--space-md);
}

.grid-5 {
    display: grid;
    grid-template-columns: repeat(5, 1fr);
    gap: var(--space-md);
}

.grid-auto {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
    gap: var(--space-md);
}

/* ---- Responsive ---- */
@media (max-width: 1024px) {
    .grid-4 { grid-template-columns: repeat(2, 1fr); }
    .grid-5 { grid-template-columns: repeat(3, 1fr); }
    .grid-3 { grid-template-columns: repeat(2, 1fr); }
}

@media (max-width: 768px) {
    .sidebar {
        transform: translateX(-100%);
    }
    .sidebar.open {
        transform: translateX(0);
    }

    .main-content {
        margin-left: 0;
    }

    .mobile-header {
        display: flex;
    }

    .page-container {
        padding: var(--space-md);
    }

    .page-title {
        font-size: var(--text-2xl);
    }

    .grid-2, .grid-3, .grid-4 {
        grid-template-columns: 1fr;
    }

    .grid-auto {
        grid-template-columns: 1fr;
    }

    .modal {
        margin: var(--space-sm);
        padding: var(--space-lg);
        max-height: calc(100vh - var(--space-md));
    }

    .tabs {
        overflow-x: auto;
        -webkit-overflow-scrolling: touch;
    }

    .toast-container {
        left: var(--space-md);
        right: var(--space-md);
    }

    .toast {
        min-width: auto;
        max-width: none;
    }
}

@media (max-width: 480px) {
    html { font-size: 14px; }

    .page-container {
        padding: var(--space-sm);
    }
}