/* ============ CSS Variables & Root ============ */
:root {
    --primary-color: #4a90d9;
    --primary-hover: #357abd;
    --secondary-color: #6c757d;
    --danger-color: #dc3545;
    --success-color: #28a745;
    
    --bg-color: #f5f7fa;
    --sidebar-bg: #ffffff;
    --content-bg: #ffffff;
    --header-bg: #ffffff;
    --text-color: #333333;
    --text-muted: #6c757d;
    --border-color: #e0e0e0;
    --hover-bg: #f0f4f8;
    --modal-overlay: rgba(0, 0, 0, 0.5);
    --shadow: 0 2px 8px rgba(0, 0, 0, 0.1);
    --shadow-lg: 0 4px 16px rgba(0, 0, 0, 0.15);
}

[data-theme="dark"] {
    --bg-color: #1a1a2e;
    --sidebar-bg: #16213e;
    --content-bg: #1f2940;
    --header-bg: #16213e;
    --text-color: #e4e4e4;
    --text-muted: #a0a0a0;
    --border-color: #2d3748;
    --hover-bg: #2d3748;
    --modal-overlay: rgba(0, 0, 0, 0.7);
    --shadow: 0 2px 8px rgba(0, 0, 0, 0.3);
    --shadow-lg: 0 4px 16px rgba(0, 0, 0, 0.4);
}

/* ============ Reset & Base ============ */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    background-color: var(--bg-color);
    color: var(--text-color);
    line-height: 1.6;
    min-height: 100vh;
}

.hidden {
    display: none !important;
}

/* ============ Buttons ============ */
.btn {
    padding: 8px 16px;
    border: none;
    border-radius: 6px;
    cursor: pointer;
    font-size: 14px;
    font-weight: 500;
    transition: all 0.2s ease;
    display: inline-flex;
    align-items: center;
    gap: 6px;
}

.btn:hover {
    transform: translateY(-1px);
}

.btn-primary {
    background-color: var(--primary-color);
    color: white;
}

.btn-primary:hover {
    background-color: var(--primary-hover);
}

.btn-secondary {
    background-color: var(--secondary-color);
    color: white;
}

.btn-secondary:hover {
    background-color: #5a6268;
}

.btn-danger {
    background-color: var(--danger-color);
    color: white;
}

.btn-danger:hover {
    background-color: #c82333;
}

.btn-small {
    padding: 4px 10px;
    font-size: 12px;
}

.btn-icon {
    background: transparent;
    color: var(--text-color);
    padding: 8px;
    font-size: 18px;
}

.btn-icon:hover {
    background-color: var(--hover-bg);
}

/* ============ Login Page ============ */
.login-page {
    display: flex;
    justify-content: center;
    align-items: center;
    min-height: 100vh;
    padding: 20px;
}

.login-container {
    background-color: var(--content-bg);
    padding: 40px;
    border-radius: 12px;
    box-shadow: var(--shadow-lg);
    width: 100%;
    max-width: 400px;
    text-align: center;
}

.login-container h1 {
    margin-bottom: 30px;
    color: var(--primary-color);
}

.form-group {
    margin-bottom: 20px;
    text-align: left;
}

.form-group label {
    display: block;
    margin-bottom: 6px;
    font-weight: 500;
    color: var(--text-color);
}

.form-group input {
    width: 100%;
    padding: 12px;
    border: 1px solid var(--border-color);
    border-radius: 6px;
    font-size: 14px;
    background-color: var(--bg-color);
    color: var(--text-color);
    transition: border-color 0.2s;
}

.form-group input:focus {
    outline: none;
    border-color: var(--primary-color);
}

#loginForm .btn {
    width: 100%;
    padding: 12px;
    font-size: 16px;
}

.error-message {
    color: var(--danger-color);
    margin-top: 15px;
    font-size: 14px;
}

.login-hint {
    margin-top: 20px;
    font-size: 12px;
    color: var(--text-muted);
}

/* ============ Main Application Layout ============ */
.main-app {
    display: flex;
    flex-direction: column;
    height: 100vh;
}

/* ============ Top Menu ============ */
.top-menu {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 12px 24px;
    background-color: var(--header-bg);
    border-bottom: 1px solid var(--border-color);
    box-shadow: var(--shadow);
    z-index: 100;
}

.menu-left h1 {
    font-size: 20px;
    color: var(--primary-color);
}

.menu-right {
    display: flex;
    align-items: center;
    gap: 12px;
}

.user-info {
    color: var(--text-muted);
    font-size: 14px;
}

/* ============ App Container ============ */
.app-container {
    display: flex;
    flex: 1;
    overflow: hidden;
}

/* ============ Sidebar ============ */
.sidebar {
    width: 280px;
    background-color: var(--sidebar-bg);
    border-right: 1px solid var(--border-color);
    display: flex;
    flex-direction: column;
    overflow: hidden;
}

.sidebar-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 16px;
    border-bottom: 1px solid var(--border-color);
}

.sidebar-header h2 {
    font-size: 16px;
    font-weight: 600;
}

.folder-list {
    flex: 1;
    overflow-y: auto;
    padding: 8px;
}

/* ============ Folder & Article Items ============ */
.folder-item {
    margin-bottom: 4px;
}

.folder-header {
    display: flex;
    align-items: center;
    padding: 10px 12px;
    border-radius: 6px;
    cursor: pointer;
    transition: background-color 0.2s;
    gap: 8px;
}

.folder-header:hover {
    background-color: var(--hover-bg);
}

.folder-header.active {
    background-color: var(--hover-bg);
}

.folder-icon {
    font-size: 16px;
    transition: transform 0.2s;
}

.folder-icon.expanded {
    transform: rotate(90deg);
}

.folder-name {
    flex: 1;
    font-weight: 500;
    font-size: 14px;
}

.folder-actions {
    display: flex;
    gap: 4px;
    opacity: 0;
    transition: opacity 0.2s;
}

.folder-header:hover .folder-actions {
    opacity: 1;
}

.folder-action-btn {
    padding: 4px 6px;
    background: transparent;
    border: none;
    cursor: pointer;
    font-size: 12px;
    border-radius: 4px;
    color: var(--text-muted);
}

.folder-action-btn:hover {
    background-color: var(--border-color);
    color: var(--text-color);
}

.article-list {
    margin-left: 24px;
    overflow: hidden;
    max-height: 0;
    transition: max-height 0.3s ease;
}

.article-list.expanded {
    max-height: 1000px;
}

.article-item {
    display: flex;
    align-items: center;
    padding: 8px 12px;
    border-radius: 6px;
    cursor: pointer;
    transition: background-color 0.2s;
    font-size: 13px;
    color: var(--text-muted);
}

.article-item:hover {
    background-color: var(--hover-bg);
    color: var(--text-color);
}

.article-item.active {
    background-color: var(--primary-color);
    color: white;
}

.article-item::before {
    content: '📄';
    margin-right: 8px;
    font-size: 12px;
}

.add-article-btn {
    display: flex;
    align-items: center;
    padding: 8px 12px;
    border-radius: 6px;
    cursor: pointer;
    transition: background-color 0.2s;
    font-size: 13px;
    color: var(--primary-color);
    border: 1px dashed var(--border-color);
    margin-top: 4px;
}

.add-article-btn:hover {
    background-color: var(--hover-bg);
}

/* ============ Content Area ============ */
.content {
    flex: 1;
    display: flex;
    flex-direction: column;
    overflow: hidden;
    background-color: var(--content-bg);
}

.editor-area {
    display: flex;
    flex-direction: column;
    height: 100%;
    padding: 20px;
}

.editor-header {
    display: flex;
    align-items: center;
    gap: 16px;
    margin-bottom: 16px;
}

.article-title-input {
    flex: 1;
    padding: 12px 16px;
    font-size: 24px;
    font-weight: 600;
    border: none;
    border-bottom: 2px solid var(--border-color);
    background: transparent;
    color: var(--text-color);
    transition: border-color 0.2s;
}

.article-title-input:focus {
    outline: none;
    border-color: var(--primary-color);
}

.editor-actions {
    display: flex;
    gap: 8px;
}

/* ============ Editor Toolbar ============ */
.editor-toolbar {
    display: flex;
    flex-wrap: wrap;
    align-items: center;
    gap: 4px;
    padding: 8px 12px;
    background-color: var(--bg-color);
    border: 1px solid var(--border-color);
    border-bottom: none;
    border-radius: 8px 8px 0 0;
}

.toolbar-btn {
    padding: 6px 10px;
    background: transparent;
    border: 1px solid transparent;
    border-radius: 4px;
    cursor: pointer;
    font-size: 14px;
    color: var(--text-color);
    transition: all 0.2s;
}

.toolbar-btn:hover {
    background-color: var(--hover-bg);
    border-color: var(--border-color);
}

.toolbar-btn.active {
    background-color: var(--primary-color);
    color: white;
}

.toolbar-select {
    padding: 6px 10px;
    border: 1px solid var(--border-color);
    border-radius: 4px;
    background-color: var(--bg-color);
    color: var(--text-color);
    font-size: 13px;
    cursor: pointer;
}

.toolbar-separator {
    width: 1px;
    height: 24px;
    background-color: var(--border-color);
    margin: 0 8px;
}

/* ============ Rich Text Editor ============ */
.editor {
    flex: 1;
    padding: 20px;
    border: 1px solid var(--border-color);
    border-radius: 0 0 8px 8px;
    overflow-y: auto;
    background-color: var(--bg-color);
    min-height: 300px;
    font-size: 15px;
    line-height: 1.8;
}

.editor:focus {
    outline: none;
    border-color: var(--primary-color);
}

.editor:empty::before {
    content: attr(placeholder);
    color: var(--text-muted);
    pointer-events: none;
}

.editor img {
    max-width: 100%;
    height: auto;
    border-radius: 8px;
    margin: 10px 0;
}

.editor table {
    width: 100%;
    border-collapse: collapse;
    margin: 15px 0;
}

.editor table td,
.editor table th {
    border: 1px solid var(--border-color);
    padding: 10px;
    text-align: left;
}

.editor table th {
    background-color: var(--hover-bg);
    font-weight: 600;
}

/* ============ Empty State ============ */
.empty-state {
    flex: 1;
    display: flex;
    justify-content: center;
    align-items: center;
    padding: 40px;
}

.empty-state-content {
    text-align: center;
    color: var(--text-muted);
}

.empty-icon {
    font-size: 64px;
    display: block;
    margin-bottom: 20px;
}

.empty-state h2 {
    margin-bottom: 10px;
    color: var(--text-color);
}

/* ============ Modal Styles ============ */
.modal-overlay {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background-color: var(--modal-overlay);
    display: flex;
    justify-content: center;
    align-items: center;
    z-index: 1000;
}

.modal {
    background-color: var(--content-bg);
    border-radius: 12px;
    box-shadow: var(--shadow-lg);
    width: 100%;
    max-width: 450px;
    max-height: 90vh;
    overflow: hidden;
    animation: modalSlide 0.2s ease;
}

@keyframes modalSlide {
    from {
        opacity: 0;
        transform: translateY(-20px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.modal-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 16px 20px;
    border-bottom: 1px solid var(--border-color);
}

.modal-header h3 {
    font-size: 18px;
    font-weight: 600;
}

.modal-close {
    background: transparent;
    border: none;
    font-size: 24px;
    cursor: pointer;
    color: var(--text-muted);
    padding: 0;
    line-height: 1;
}

.modal-close:hover {
    color: var(--text-color);
}

.modal-body {
    padding: 20px;
}

.modal-footer {
    display: flex;
    justify-content: flex-end;
    gap: 10px;
    padding: 16px 20px;
    border-top: 1px solid var(--border-color);
}

.form-row {
    display: flex;
    gap: 16px;
}

.form-row .form-group {
    flex: 1;
}

/* ============ Export Options ============ */
.export-options {
    display: flex;
    flex-direction: column;
    gap: 12px;
    margin-top: 16px;
}

.export-options .btn {
    justify-content: center;
    padding: 14px;
}

/* ============ Image Preview ============ */
.image-preview {
    margin-top: 16px;
    text-align: center;
}

.image-preview img {
    max-width: 100%;
    max-height: 200px;
    border-radius: 8px;
    border: 1px solid var(--border-color);
}

/* ============ Scrollbar Styling ============ */
::-webkit-scrollbar {
    width: 8px;
}

::-webkit-scrollbar-track {
    background: var(--bg-color);
}

::-webkit-scrollbar-thumb {
    background: var(--border-color);
    border-radius: 4px;
}

::-webkit-scrollbar-thumb:hover {
    background: var(--text-muted);
}

/* ============ User Management Styles ============ */
.user-management-header {
    display: flex;
    justify-content: flex-end;
    margin-bottom: 16px;
}

.user-list {
    max-height: 400px;
    overflow-y: auto;
}

.user-item {
    display: flex;
    align-items: center;
    padding: 12px 16px;
    border: 1px solid var(--border-color);
    border-radius: 8px;
    margin-bottom: 8px;
    background-color: var(--bg-color);
    transition: background-color 0.2s;
}

.user-item:hover {
    background-color: var(--hover-bg);
}

.user-avatar {
    width: 40px;
    height: 40px;
    border-radius: 50%;
    background-color: var(--primary-color);
    color: white;
    display: flex;
    align-items: center;
    justify-content: center;
    font-weight: 600;
    font-size: 16px;
    margin-right: 12px;
}

.user-info-details {
    flex: 1;
}

.user-info-details .user-name {
    font-weight: 600;
    color: var(--text-color);
}

.user-info-details .user-username {
    font-size: 13px;
    color: var(--text-muted);
}

.user-badges {
    display: flex;
    gap: 6px;
    margin-right: 12px;
}

.badge {
    padding: 2px 8px;
    border-radius: 12px;
    font-size: 11px;
    font-weight: 600;
    text-transform: uppercase;
}

.badge-admin {
    background-color: var(--primary-color);
    color: white;
}

.badge-user {
    background-color: var(--secondary-color);
    color: white;
}

.user-actions {
    display: flex;
    gap: 6px;
}

.user-action-btn {
    padding: 6px 10px;
    background: transparent;
    border: 1px solid var(--border-color);
    border-radius: 4px;
    cursor: pointer;
    font-size: 14px;
    color: var(--text-color);
    transition: all 0.2s;
}

.user-action-btn:hover {
    background-color: var(--hover-bg);
}

.user-action-btn.delete:hover {
    background-color: var(--danger-color);
    color: white;
    border-color: var(--danger-color);
}

.checkbox-label {
    display: flex;
    align-items: center;
    gap: 8px;
    cursor: pointer;
}

.checkbox-label input[type="checkbox"] {
    width: 18px;
    height: 18px;
    cursor: pointer;
}

.form-hint {
    font-size: 12px;
    color: var(--text-muted);
    margin-top: 4px;
    display: block;
}

.empty-user-list {
    text-align: center;
    padding: 40px 20px;
    color: var(--text-muted);
}

/* ============ Responsive Design ============ */
@media (max-width: 768px) {
    .sidebar {
        width: 100%;
        position: absolute;
        left: -100%;
        top: 60px;
        bottom: 0;
        z-index: 50;
        transition: left 0.3s ease;
    }
    
    .sidebar.open {
        left: 0;
    }
    
    .app-container {
        flex-direction: column;
    }
    
    .editor-header {
        flex-direction: column;
        align-items: stretch;
    }
    
    .editor-actions {
        justify-content: stretch;
    }
    
    .editor-actions .btn {
        flex: 1;
        justify-content: center;
    }
}