.header {
    background: var(--primary-dark);
    border-bottom: 1px solid rgba(255, 255, 255, 0.1);
    padding: var(--spacing-md) var(--spacing-xl);
    position: sticky;
    top: 0;
    z-index: 100;
    box-shadow: 0 2px 8px rgba(0, 0, 0, 0.3);
}

.header-content {
    max-width: 1920px;
    margin: 0 auto;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.logo-container {
    display: flex;
    align-items: center;
    gap: var(--spacing-md);
}

.logo-image {
    height: 40px;
    width: auto;
}

.logo-text {
    font-size: 1.5rem;
    font-weight: 700;
    color: white;
}

.user-info {
    display: flex;
    align-items: center;
    gap: var(--spacing-md);
}

.user-name {
    color: rgba(255, 255, 255, 0.9);
    font-size: 0.875rem;
    font-weight: 500;
}

.main-container {
    display: grid;
    grid-template-columns: 280px 240px 1fr;
    max-width: 1920px;
    margin: 0 auto;
    min-height: calc(100vh - 65px);
    gap: 0;
    position: relative;
    padding-left: 60px;
    transition: padding-left 0.3s ease;
    background-color: var(--background);
}

.nav-sidebar.expanded ~ .main-container {
    padding-left: 300px;
}

.document-sidebar {
    background: var(--surface);
    border-right: 1px solid var(--border);
    overflow: hidden;
    height: calc(100vh - 65px);
    position: sticky;
    top: 65px;
    display: flex;
    flex-direction: column;
    z-index: 1;
}

.document-sidebar .sidebar-content {
    padding: var(--spacing-md);
    display: flex;
    flex-direction: column;
    gap: var(--spacing-sm);
    height: 100%;
    overflow: hidden;
}

.sidebar h3,
.document-sidebar h3 {
    font-size: 0.8rem;
    font-weight: 700;
    color: var(--text-primary);
    margin-bottom: var(--spacing-xs);
    text-transform: uppercase;
    letter-spacing: 0.05em;
    flex-shrink: 0;
}

.upload-section {
    flex-shrink: 0;
}

.upload-zone {
    border: 2px dashed var(--border);
    border-radius: var(--radius-md);
    padding: var(--spacing-sm) var(--spacing-md);
    text-align: center;
    cursor: pointer;
    transition: var(--transition);
    background: var(--background);
}

.upload-zone:hover {
    border-color: var(--primary-color);
    background: rgba(37, 99, 235, 0.05);
}

.upload-zone.dragging {
    border-color: var(--primary-color);
    background: rgba(37, 99, 235, 0.1);
}

.upload-zone p {
    font-size: 0.875rem;
    color: var(--text-secondary);
    margin-bottom: var(--spacing-xs);
}

.upload-hint {
    font-size: 0.65rem;
    line-height: 1.2;
    color: var(--text-secondary);
}

.search-section {
    margin-bottom: var(--spacing-xs);
    flex-shrink: 0;
}

.search-input {
    width: 100%;
    padding: var(--spacing-sm) var(--spacing-md);
    border: 1px solid var(--border);
    border-radius: var(--radius-md);
    font-size: 0.875rem;
    transition: var(--transition);
}

.search-input:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 3px rgba(138, 0, 229, 0.2);
}

.documents-section {
    flex: 1;
    min-height: 0;
    display: flex;
    flex-direction: column;
    overflow: hidden;
}

.documents-list {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-xs);
    flex: 1;
    overflow-y: auto;
    min-height: 0;
}