/* =============================================
   Knowledge Tree - Main Stylesheet
   ============================================= */

/* CSS Variables - Dark Theme */
:root {
    /* Colors */
    --bg-primary: #0f0f23;
    --bg-secondary: #1a1a2e;
    --bg-tertiary: #16213e;
    --bg-surface: rgba(26, 26, 46, 0.8);
    --bg-hover: rgba(99, 102, 241, 0.1);
    --bg-active: rgba(99, 102, 241, 0.2);

    --text-primary: #e2e8f0;
    --text-secondary: #94a3b8;
    --text-muted: #64748b;
    --text-inverse: #0f172a;

    --accent-primary: #6366f1;
    --accent-secondary: #818cf8;
    --accent-tertiary: #a5b4fc;
    --accent-gradient: linear-gradient(135deg, #6366f1, #8b5cf6);

    --success: #10b981;
    --warning: #f59e0b;
    --error: #ef4444;
    --info: #3b82f6;

    --border-color: rgba(148, 163, 184, 0.1);
    --border-hover: rgba(99, 102, 241, 0.3);

    --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.3);
    --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.4);
    --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.5);
    --shadow-xl: 0 20px 25px -5px rgba(0, 0, 0, 0.6);
    --shadow-glow: 0 0 20px rgba(99, 102, 241, 0.3);

    /* Glass Effect */
    --glass-bg: rgba(26, 26, 46, 0.7);
    --glass-border: rgba(148, 163, 184, 0.1);
    --glass-blur: blur(20px);

    /* Typography */
    --font-sans: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
    --font-mono: 'JetBrains Mono', 'Fira Code', monospace;

    /* Spacing */
    --navbar-height: 64px;
    --sidebar-width: 280px;

    /* Transitions */
    --transition-fast: 150ms ease;
    --transition-normal: 250ms ease;
    --transition-slow: 350ms ease;

    /* Border Radius */
    --radius-sm: 6px;
    --radius-md: 8px;
    --radius-lg: 12px;
    --radius-xl: 16px;
    --radius-full: 9999px;
}

/* Reset */
*,
*::before,
*::after {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

html {
    font-size: 16px;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

body {
    font-family: var(--font-sans);
    background: var(--bg-primary);
    color: var(--text-primary);
    line-height: 1.6;
    min-height: 100vh;
}

a {
    color: var(--accent-secondary);
    text-decoration: none;
    transition: color var(--transition-fast);
}

a:hover {
    color: var(--accent-tertiary);
}

img {
    max-width: 100%;
    height: auto;
}

button {
    cursor: pointer;
    font-family: inherit;
}

input, textarea, select {
    font-family: inherit;
}

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

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

::-webkit-scrollbar-thumb {
    background: var(--text-muted);
    border-radius: var(--radius-full);
}

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

/* =============================================
   Authentication Pages
   ============================================= */

.auth-container {
    display: flex;
    align-items: center;
    justify-content: center;
    min-height: 100vh;
    padding: 1.5rem;
    position: relative;
    overflow: hidden;
}

.auth-bg {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: radial-gradient(ellipse at 20% 50%, rgba(99, 102, 241, 0.15) 0%, transparent 50%),
                radial-gradient(ellipse at 80% 20%, rgba(139, 92, 246, 0.1) 0%, transparent 50%),
                radial-gradient(ellipse at 50% 80%, rgba(79, 70, 229, 0.1) 0%, transparent 50%);
    z-index: 0;
}

.auth-card {
    position: relative;
    z-index: 1;
    width: 100%;
    max-width: 380px;
    background: var(--glass-bg);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    border: 1px solid var(--glass-border);
    border-radius: 16px;
    padding: 2rem;
    box-shadow: 0 25px 50px -12px rgba(0, 0, 0, 0.5);
}

@media (max-width: 480px) {
    .auth-card {
        padding: 1.5rem;
        border-radius: var(--radius-lg);
    }
}

.auth-header {
    text-align: center;
    margin-bottom: 1.5rem;
}

.auth-logo {
    margin-bottom: 0.75rem;
}

.auth-header h1 {
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--text-primary);
    margin-bottom: 0.35rem;
}

.auth-header p {
    color: var(--text-secondary);
    font-size: 0.85rem;
}

@media (max-width: 480px) {
    .auth-header h1 {
        font-size: 1.3rem;
    }
}

.auth-form {
    display: flex;
    flex-direction: column;
    gap: 1rem;
}

.auth-footer {
    text-align: center;
    margin-top: 1.25rem;
    padding-top: 1.25rem;
    border-top: 1px solid var(--border-color);
}

.auth-footer p {
    color: var(--text-secondary);
    font-size: 0.9rem;
}

/* =============================================
   Form Elements
   ============================================= */

.form-group {
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
}

.form-group label {
    font-size: 0.875rem;
    font-weight: 500;
    color: var(--text-secondary);
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.form-group label i {
    font-size: 0.75rem;
    color: var(--text-muted);
}

.form-group small {
    font-size: 0.75rem;
    color: var(--text-muted);
}

.form-group input,
.form-group textarea,
.form-group select {
    width: 100%;
    padding: 0.625rem 0.875rem;
    background: var(--bg-primary);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-sm);
    color: var(--text-primary);
    font-size: 0.875rem;
    transition: all var(--transition-fast);
}

.form-group input:focus,
.form-group textarea:focus,
.form-group select:focus {
    outline: none;
    border-color: var(--accent-primary);
    box-shadow: 0 0 0 2px rgba(99, 102, 241, 0.1);
}

.form-group input::placeholder,
.form-group textarea::placeholder {
    color: var(--text-muted);
}

.form-row {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 1rem;
}

.password-input {
    position: relative;
}

.password-input input {
    padding-right: 2.5rem;
}

.password-toggle {
    position: absolute;
    right: 0.75rem;
    top: 50%;
    transform: translateY(-50%);
    background: none;
    border: none;
    color: var(--text-muted);
    padding: 0.25rem;
    transition: color var(--transition-fast);
}

.password-toggle:hover {
    color: var(--text-secondary);
}

.optional {
    font-size: 0.75rem;
    color: var(--text-muted);
    font-weight: 400;
}

/* Color Picker */
.color-picker {
    display: flex;
    align-items: center;
    gap: 1rem;
}

.color-picker input[type="color"] {
    width: 40px;
    height: 40px;
    padding: 2px;
    background: var(--bg-secondary);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    cursor: pointer;
}

.color-presets {
    display: flex;
    gap: 0.5rem;
}

.color-preset {
    width: 28px;
    height: 28px;
    border-radius: var(--radius-full);
    border: 2px solid transparent;
    cursor: pointer;
    transition: all var(--transition-fast);
}

.color-preset:hover {
    transform: scale(1.1);
}

.color-preset.active {
    border-color: white;
    box-shadow: var(--shadow-glow);
}

/* Icon Picker */
.icon-picker {
    display: flex;
    flex-wrap: wrap;
    gap: 0.5rem;
}

.icon-option {
    width: 40px;
    height: 40px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: var(--bg-secondary);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    color: var(--text-secondary);
    transition: all var(--transition-fast);
}

.icon-option:hover {
    border-color: var(--accent-primary);
    color: var(--accent-primary);
}

.icon-option.active {
    background: var(--accent-primary);
    border-color: var(--accent-primary);
    color: white;
}

/* =============================================
   Buttons
   ============================================= */

.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 0.5rem;
    padding: 0.75rem 1.5rem;
    font-size: 0.9rem;
    font-weight: 500;
    border: none;
    border-radius: var(--radius-md);
    transition: all var(--transition-fast);
    cursor: pointer;
    white-space: nowrap;
}

.btn-primary {
    background: var(--accent-gradient);
    color: white;
    box-shadow: var(--shadow-md);
}

.btn-primary:hover {
    transform: translateY(-1px);
    box-shadow: var(--shadow-lg), var(--shadow-glow);
}

.btn-primary:active {
    transform: translateY(0);
}

.btn-secondary {
    background: var(--bg-secondary);
    color: var(--text-primary);
    border: 1px solid var(--border-color);
}

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

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

.btn-danger:hover {
    background: #dc2626;
}

.btn-full {
    width: 100%;
}

.btn-lg {
    padding: 1rem 2rem;
    font-size: 1rem;
}

.btn-sm {
    padding: 0.5rem 1rem;
    font-size: 0.8rem;
}

.btn-icon {
    width: 36px;
    height: 36px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: transparent;
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    color: var(--text-secondary);
    transition: all var(--transition-fast);
}

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

.btn-icon.btn-sm {
    width: 28px;
    height: 28px;
    font-size: 0.75rem;
}

/* =============================================
   Alerts
   ============================================= */

.alert {
    padding: 1rem;
    border-radius: var(--radius-md);
    display: flex;
    align-items: flex-start;
    gap: 0.75rem;
    margin-bottom: 1rem;
}

.alert-error {
    background: rgba(239, 68, 68, 0.1);
    border: 1px solid rgba(239, 68, 68, 0.2);
    color: #fca5a5;
}

.alert-error i {
    margin-top: 0.1rem;
}

.alert-error ul {
    list-style: none;
    display: flex;
    flex-direction: column;
    gap: 0.25rem;
}

/* =============================================
   App Layout
   ============================================= */

.app-layout {
    display: flex;
    flex-direction: column;
    height: 100vh;
    overflow: hidden;
}

@media (max-width: 768px) {
    .app-layout {
        height: 100dvh;
    }
}

.app-body {
    display: flex;
    flex: 1;
    overflow: hidden;
}

/* =============================================
   Navbar
   ============================================= */

.navbar {
    height: var(--navbar-height);
    background: var(--bg-secondary);
    border-bottom: 1px solid var(--border-color);
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 0 1rem;
    z-index: 100;
}

.navbar-left {
    display: flex;
    align-items: center;
    gap: 0.75rem;
}

.sidebar-toggle {
    display: none;
    width: 32px;
    height: 32px;
    align-items: center;
    justify-content: center;
    background: transparent;
    border: 1px solid var(--border-color);
    border-radius: var(--radius-sm);
    color: var(--text-secondary);
    cursor: pointer;
    transition: all var(--transition-fast);
}

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

.navbar-brand {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    font-weight: 600;
    font-size: 1rem;
    color: var(--text-primary);
}

.navbar-center {
    flex: 1;
    max-width: 360px;
    margin: 0 1.5rem;
}

.search-box {
    position: relative;
    display: flex;
    align-items: center;
}

.search-box i {
    position: absolute;
    left: 0.75rem;
    color: var(--text-muted);
    font-size: 0.8rem;
}

.search-box input {
    width: 100%;
    padding: 0.5rem 0.75rem 0.5rem 2rem;
    padding-right: 3rem;
    background: var(--bg-primary);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-sm);
    color: var(--text-primary);
    font-size: 0.8rem;
    transition: all var(--transition-fast);
}

.search-box input:focus {
    outline: none;
    border-color: var(--accent-primary);
    box-shadow: 0 0 0 2px rgba(99, 102, 241, 0.1);
}

.search-box input::placeholder {
    color: var(--text-muted);
}

.search-box kbd {
    position: absolute;
    right: 0.75rem;
    padding: 0.15rem 0.5rem;
    background: var(--bg-primary);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-sm);
    font-family: var(--font-mono);
    font-size: 0.7rem;
    color: var(--text-muted);
}

.search-results {
    position: absolute;
    top: calc(100% + 0.5rem);
    left: 0;
    right: 0;
    background: var(--bg-secondary);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-xl);
    max-height: 400px;
    overflow-y: auto;
    display: none;
    z-index: 200;
}

.search-results.active {
    display: block;
}

.search-result-item {
    padding: 0.75rem 1rem;
    display: flex;
    align-items: center;
    gap: 0.75rem;
    cursor: pointer;
    transition: background var(--transition-fast);
}

.search-result-item:hover {
    background: var(--bg-hover);
}

.search-result-item .result-icon {
    width: 32px;
    height: 32px;
    display: flex;
    align-items: center;
    justify-content: center;
    border-radius: var(--radius-md);
    background: var(--bg-primary);
}

.search-result-item .result-info {
    flex: 1;
    min-width: 0;
}

.search-result-item .result-title {
    font-size: 0.875rem;
    font-weight: 500;
    color: var(--text-primary);
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
}

.search-result-item .result-path {
    font-size: 0.75rem;
    color: var(--text-muted);
}

.search-empty {
    padding: 2rem;
    text-align: center;
    color: var(--text-muted);
    font-size: 0.875rem;
}

.navbar-right {
    display: flex;
    align-items: center;
    gap: 0.75rem;
}

.user-menu {
    position: relative;
}

.user-avatar {
    width: 32px;
    height: 32px;
    border-radius: var(--radius-full);
    background: var(--bg-primary);
    border: 1px solid var(--border-color);
    display: flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    transition: all var(--transition-fast);
}

.user-avatar:hover {
    border-color: var(--accent-primary);
}

.avatar-text {
    color: var(--text-primary);
    font-weight: 600;
    font-size: 0.75rem;
}

.dropdown-menu {
    position: absolute;
    top: calc(100% + 0.5rem);
    right: 0;
    width: 200px;
    background: var(--bg-secondary);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-xl);
    padding: 0.5rem;
    display: none;
    z-index: 200;
}

.dropdown-menu.active {
    display: block;
}

.dropdown-header {
    padding: 0.75rem;
    border-bottom: 1px solid var(--border-color);
}

.user-name {
    font-weight: 500;
    font-size: 0.875rem;
}

.dropdown-divider {
    height: 1px;
    background: var(--border-color);
    margin: 0.25rem 0;
}

.dropdown-item {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    padding: 0.6rem 0.75rem;
    border-radius: var(--radius-md);
    color: var(--text-secondary);
    font-size: 0.875rem;
    transition: all var(--transition-fast);
}

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

/* =============================================
   Sidebar
   ============================================= */

.sidebar {
    width: var(--sidebar-width);
    background: var(--bg-secondary);
    border-right: 1px solid var(--border-color);
    display: flex;
    flex-direction: column;
    overflow: hidden;
    transition: transform var(--transition-normal);
}

.sidebar-overlay {
    display: none;
}

@media (max-width: 1024px) {
    .sidebar-overlay {
        display: none;
        position: fixed;
        top: var(--navbar-height);
        left: 0;
        right: 0;
        bottom: 0;
        background: rgba(0, 0, 0, 0.5);
        z-index: 89;
    }

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

.sidebar-content {
    flex: 1;
    overflow-y: auto;
    padding: 0.75rem 0;
}

.sidebar-section {
    margin-bottom: 0.5rem;
}

.sidebar-empty {
    padding: 2rem 1rem;
    text-align: center;
    color: var(--text-muted);
    font-size: 0.85rem;
}

.sidebar-empty p {
    margin-bottom: 0.75rem;
}

.sidebar-footer {
    padding: 0.75rem 1rem;
    border-top: 1px solid var(--border-color);
    font-size: 0.75rem;
    color: var(--text-muted);
}

/* Tree Sidebar */
.tree-sidebar {
    padding: 0 0.5rem;
}

.tree-list {
    list-style: none;
}

.tree-list[hidden] {
    display: none !important;
}

.tree-nested {
    padding-left: 1.25rem;
}

.tree-item {
    margin: 0.1rem 0;
}

.tree-node-row {
    display: flex;
    align-items: center;
    gap: 0.25rem;
    padding: 0.2rem 0;
}

.tree-toggle {
    width: 20px;
    height: 20px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: none;
    border: none;
    color: var(--text-muted);
    cursor: pointer;
    transition: transform var(--transition-fast);
    flex-shrink: 0;
}

.tree-toggle i {
    font-size: 0.6rem;
}

.tree-toggle.collapsed {
    transform: rotate(-90deg);
}

.tree-spacer {
    width: 20px;
    flex-shrink: 0;
}

.tree-label {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    padding: 0.3rem 0.5rem;
    border-radius: var(--radius-sm);
    color: var(--text-secondary);
    font-size: 0.8rem;
    cursor: pointer;
    transition: all var(--transition-fast);
    flex: 1;
    min-width: 0;
}

.tree-label:hover {
    background: var(--bg-hover);
    color: var(--text-primary);
}

.tree-label i {
    font-size: 0.5rem;
    flex-shrink: 0;
}

.tree-label span {
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
}

/* =============================================
   Main Content
   ============================================= */

.main-content {
    flex: 1;
    display: flex;
    flex-direction: column;
    overflow: hidden;
    position: relative;
}

/* Toolbar Section */
.toolbar-section {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 0.75rem 1.5rem;
    background: var(--bg-secondary);
    border-bottom: 1px solid var(--border-color);
    gap: 1rem;
}

.toolbar-left {
    display: flex;
    align-items: baseline;
    gap: 0.5rem;
}

.toolbar-title {
    font-size: 1rem;
    font-weight: 600;
    color: var(--text-primary);
}

.toolbar-subtitle {
    font-size: 0.8rem;
    color: var(--text-muted);
}

.toolbar-actions {
    display: flex;
    align-items: center;
    gap: 0.25rem;
}

.toolbar-action {
    width: 32px;
    height: 32px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: transparent;
    border: 1px solid transparent;
    border-radius: var(--radius-sm);
    color: var(--text-secondary);
    font-size: 0.85rem;
    cursor: pointer;
    transition: all var(--transition-fast);
}

.toolbar-action:hover {
    background: var(--bg-hover);
    border-color: var(--border-color);
    color: var(--text-primary);
}

@media (max-width: 768px) {
    .toolbar-section {
        padding: 0.5rem 1rem;
    }
    .toolbar-subtitle {
        display: none;
    }
}

@media (max-width: 480px) {
    .toolbar-action {
        width: 28px;
        height: 28px;
        font-size: 0.8rem;
    }
}

@media (max-width: 480px) {
    .quick-actions {
        display: grid;
        grid-template-columns: 1fr 1fr;
        gap: 0.5rem;
    }
    .action-card {
        justify-content: center;
        padding: 0.6rem 0.5rem;
    }
}

/* Tree Container */
.tree-container {
    flex: 1;
    position: relative;
    overflow: hidden;
    background: var(--bg-primary);
}

.tree-controls {
    position: absolute;
    top: 1rem;
    right: 1rem;
    z-index: 50;
    display: flex;
    gap: 0.5rem;
}

.zoom-controls {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    padding: 0.5rem;
    background: var(--glass-bg);
    backdrop-filter: var(--glass-blur);
    -webkit-backdrop-filter: var(--glass-blur);
    border: 1px solid var(--glass-border);
    border-radius: var(--radius-lg);
}

.zoom-level {
    font-size: 0.75rem;
    color: var(--text-muted);
    min-width: 40px;
    text-align: center;
    font-family: var(--font-mono);
}

.tree-viewport {
    width: 100%;
    height: 100%;
    cursor: grab;
}

.tree-viewport:active {
    cursor: grabbing;
}

.tree-svg {
    width: 100%;
    height: 100%;
}

/* Empty State */
.empty-state {
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    text-align: center;
    z-index: 10;
    padding: 2rem;
}

.empty-icon {
    margin-bottom: 1.25rem;
    opacity: 0.2;
}

.empty-icon svg {
    width: 80px;
    height: 80px;
}

.empty-state h2 {
    font-size: 1.1rem;
    font-weight: 600;
    margin-bottom: 0.35rem;
    color: var(--text-primary);
}

.empty-state p {
    color: var(--text-muted);
    margin-bottom: 1.25rem;
    max-width: 280px;
    font-size: 0.85rem;
}

.empty-state .btn {
    padding: 0.6rem 1.25rem;
    font-size: 0.85rem;
}

/* Node Panel */
.node-panel {
    position: absolute;
    top: 0;
    right: -420px;
    width: 420px;
    height: 100%;
    background: var(--bg-secondary);
    border-left: 1px solid var(--border-color);
    display: flex;
    flex-direction: column;
    z-index: 60;
    transition: right 0.25s ease;
    box-shadow: -4px 0 20px rgba(0, 0, 0, 0.3);
}

.node-panel.active {
    right: 0;
}

.panel-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 1rem 1.25rem;
    border-bottom: 1px solid var(--border-color);
    background: var(--bg-primary);
}

.panel-title {
    font-weight: 600;
    font-size: 0.9rem;
    color: var(--text-primary);
}

.panel-body {
    flex: 1;
    overflow-y: auto;
    padding: 1.25rem;
}

.panel-loading {
    display: flex;
    align-items: center;
    justify-content: center;
    height: 150px;
}

.panel-empty {
    text-align: center;
    padding: 2rem 1rem;
    color: var(--text-muted);
    font-size: 0.85rem;
}

/* Node Detail Content */
.node-detail-title {
    font-size: 1.15rem;
    font-weight: 600;
    margin-bottom: 1rem;
    color: var(--text-primary);
}

.node-detail-meta {
    display: flex;
    flex-wrap: wrap;
    gap: 0.65rem;
    margin-bottom: 1.25rem;
    padding-bottom: 1.25rem;
    border-bottom: 1px solid var(--border-color);
}

.node-meta-item {
    display: flex;
    align-items: center;
    gap: 0.35rem;
    font-size: 0.75rem;
    color: var(--text-muted);
}

.node-meta-item i {
    font-size: 0.65rem;
}

.node-detail-tags {
    display: flex;
    flex-wrap: wrap;
    gap: 0.4rem;
    margin-bottom: 1rem;
}

.node-tag {
    padding: 0.2rem 0.5rem;
    background: var(--bg-primary);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-sm);
    font-size: 0.7rem;
    color: var(--text-secondary);
}

.node-detail-content {
    font-size: 0.85rem;
    line-height: 1.75;
    color: var(--text-secondary);
}

.node-detail-content h1,
.node-detail-content h2,
.node-detail-content h3 {
    color: var(--text-primary);
    margin: 1rem 0 0.5rem;
    font-size: 1rem;
}

.node-detail-content p {
    margin-bottom: 1rem;
}

.node-detail-content code {
    background: var(--bg-primary);
    padding: 0.15rem 0.4rem;
    border-radius: var(--radius-sm);
    font-family: var(--font-mono);
    font-size: 0.85em;
}

.node-detail-content pre {
    background: var(--bg-primary);
    padding: 1rem;
    border-radius: var(--radius-md);
    overflow-x: auto;
    margin-bottom: 1rem;
}

.node-detail-content pre code {
    background: none;
    padding: 0;
}

.node-detail-content ul,
.node-detail-content ol {
    margin-bottom: 1rem;
    padding-left: 1.5rem;
}

.node-detail-content li {
    margin-bottom: 0.5rem;
}

.node-detail-content a {
    color: var(--accent-secondary);
    text-decoration: underline;
}

.node-detail-content blockquote {
    border-left: 3px solid var(--accent-primary);
    padding-left: 1rem;
    margin: 1rem 0;
    color: var(--text-muted);
    font-style: italic;
}

.node-detail-actions {
    display: flex;
    flex-wrap: wrap;
    gap: 0.65rem;
    margin-top: 1.25rem;
    padding-top: 1.25rem;
    border-top: 1px solid var(--border-color);
}

.node-detail-actions .btn {
    font-size: 0.75rem;
    padding: 0.55rem 0.9rem;
    border-radius: var(--radius-full);
}

@media (max-width: 480px) {
    .node-detail-actions {
        flex-direction: column;
    }
    .node-detail-actions .btn {
        width: 100%;
        justify-content: center;
    }
}

/* =============================================
   Node Editor
   ============================================= */

.node-editor-overlay {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: rgba(0, 0, 0, 0.6);
    backdrop-filter: blur(4px);
    -webkit-backdrop-filter: blur(4px);
    display: flex;
    align-items: center;
    justify-content: center;
    z-index: 1000;
    opacity: 0;
    visibility: hidden;
    transition: all var(--transition-normal);
}

.node-editor-overlay.active {
    opacity: 1;
    visibility: visible;
}

.node-editor {
    width: min(92%, 760px);
    max-width: 760px;
    max-height: 90vh;
    background: var(--bg-secondary);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-xl);
    box-shadow: var(--shadow-xl);
    display: flex;
    flex-direction: column;
    transform: scale(0.95) translateY(20px);
    transition: transform var(--transition-normal);
}

.node-editor-overlay.active .node-editor {
    transform: scale(1) translateY(0);
}

.editor-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 1.15rem 1.5rem;
    border-bottom: 1px solid var(--border-color);
}

.editor-title {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    font-weight: 600;
    color: var(--text-primary);
}

.editor-body {
    flex: 1;
    overflow-y: auto;
    padding: 1.75rem;
}

.editor-footer {
    display: flex;
    align-items: center;
    justify-content: flex-end;
    gap: 0.75rem;
    padding: 1.15rem 1.5rem;
    border-top: 1px solid var(--border-color);
}

/* Editor Toolbar */
.editor-toolbar {
    display: flex;
    align-items: center;
    gap: 0.25rem;
    padding: 0.5rem;
    background: var(--bg-primary);
    border: 1px solid var(--border-color);
    border-bottom: none;
    border-radius: var(--radius-md) var(--radius-md) 0 0;
}

.toolbar-btn {
    width: 32px;
    height: 32px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: none;
    border: none;
    border-radius: var(--radius-sm);
    color: var(--text-muted);
    cursor: pointer;
    transition: all var(--transition-fast);
}

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

.toolbar-divider {
    width: 1px;
    height: 20px;
    background: var(--border-color);
    margin: 0 0.25rem;
}

.form-group textarea {
    border-radius: 0 0 var(--radius-md) var(--radius-md);
    font-family: var(--font-mono);
    font-size: 0.875rem;
    resize: vertical;
    min-height: 200px;
}

.form-group,
.form-row {
    gap: 0.75rem;
}

.form-group input,
.form-group textarea,
.form-group select {
    padding: 0.75rem 0.95rem;
}

.color-picker {
    gap: 1.25rem;
}

.color-presets {
    gap: 0.6rem;
}

.icon-picker {
    gap: 0.6rem;
}

.content-preview {
    padding: 1rem;
    background: var(--bg-primary);
    border: 1px solid var(--border-color);
    border-radius: 0 0 var(--radius-md) var(--radius-md);
    min-height: 200px;
    font-size: 0.9rem;
    line-height: 1.7;
}

/* =============================================
   Context Menu
   ============================================= */

.context-menu {
    position: fixed;
    background: var(--bg-secondary);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-xl);
    padding: 0.5rem;
    min-width: 180px;
    z-index: 500;
    display: none;
}

.context-menu.active {
    display: block;
}

.context-item {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    width: 100%;
    padding: 0.6rem 0.75rem;
    background: none;
    border: none;
    border-radius: var(--radius-md);
    color: var(--text-secondary);
    font-size: 0.85rem;
    cursor: pointer;
    transition: all var(--transition-fast);
}

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

.context-item.context-danger:hover {
    background: rgba(239, 68, 68, 0.1);
    color: var(--error);
}

.context-divider {
    height: 1px;
    background: var(--border-color);
    margin: 0.25rem 0;
}

/* =============================================
   Toast Notifications
   ============================================= */

.toast-container {
    position: fixed;
    bottom: 1.5rem;
    right: 1.5rem;
    display: flex;
    flex-direction: column-reverse;
    gap: 0.75rem;
    z-index: 2000;
}

.toast {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    padding: 1rem 1.25rem;
    background: var(--bg-secondary);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-lg);
    min-width: 300px;
    max-width: 420px;
    animation: slideInRight 0.3s ease;
}

.toast-success {
    border-left: 3px solid var(--success);
}

.toast-error {
    border-left: 3px solid var(--error);
}

.toast-info {
    border-left: 3px solid var(--info);
}

.toast-icon {
    font-size: 1.1rem;
}

.toast-success .toast-icon {
    color: var(--success);
}

.toast-error .toast-icon {
    color: var(--error);
}

.toast-info .toast-icon {
    color: var(--info);
}

.toast-message {
    flex: 1;
    font-size: 0.875rem;
    color: var(--text-primary);
}

.toast-close {
    background: none;
    border: none;
    color: var(--text-muted);
    cursor: pointer;
    padding: 0.25rem;
}

@keyframes slideInRight {
    from {
        transform: translateX(100%);
        opacity: 0;
    }
    to {
        transform: translateX(0);
        opacity: 1;
    }
}

/* =============================================
   Error Page
   ============================================= */

.error-page {
    display: flex;
    align-items: center;
    justify-content: center;
    min-height: 100vh;
    background: var(--bg-primary);
}

.error-content {
    text-align: center;
}

.error-content h1 {
    font-size: 5rem;
    font-weight: 700;
    background: var(--accent-gradient);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    line-height: 1;
    margin-bottom: 0.75rem;
}

.error-content p {
    font-size: 1rem;
    color: var(--text-secondary);
    margin-bottom: 1.5rem;
}

@media (max-width: 480px) {
    .error-content h1 {
        font-size: 3.5rem;
    }
    .error-content p {
        font-size: 0.9rem;
        padding: 0 1rem;
    }
}

/* =============================================
   Spinner
   ============================================= */

.spinner {
    width: 40px;
    height: 40px;
    border: 3px solid var(--border-color);
    border-top-color: var(--accent-primary);
    border-radius: 50%;
    animation: spin 0.8s linear infinite;
}

@keyframes spin {
    to {
        transform: rotate(360deg);
    }
}

/* =============================================
   Responsive
   ============================================= */

@media (max-width: 1024px) {
    .sidebar-toggle {
        display: flex;
    }

    .sidebar {
        position: fixed;
        top: var(--navbar-height);
        left: 0;
        bottom: 0;
        z-index: 90;
        transform: translateX(-100%);
        box-shadow: var(--shadow-xl);
    }

    .sidebar.active {
        transform: translateX(0);
    }

    .navbar-center {
        display: none;
    }

    .node-panel {
        width: 100%;
        right: -100%;
    }

    .tree-controls {
        top: 0.75rem;
        right: 0.75rem;
    }
}

@media (max-width: 768px) {
    .form-row {
        grid-template-columns: 1fr;
    }

    .zoom-controls {
        display: none;
    }

    .empty-state h2 {
        font-size: 1.25rem;
    }

    .empty-state p {
        font-size: 0.85rem;
    }

    .node-editor {
        width: 95%;
        max-height: 95vh;
        border-radius: var(--radius-lg);
    }

    .editor-body {
        padding: 1rem;
    }

    .editor-header,
    .editor-footer {
        padding: 0.75rem 1rem;
    }
}

@media (max-width: 480px) {
    .navbar-brand span {
        display: none;
    }

    .navbar {
        padding: 0 0.75rem;
    }

    .sidebar {
        width: 100%;
    }

    .tree-controls {
        top: 0.5rem;
        right: 0.5rem;
    }

    .zoom-controls {
        padding: 0.35rem;
        gap: 0.25rem;
    }

    .btn-icon {
        width: 32px;
        height: 32px;
    }

    .panel-header,
    .panel-body {
        padding: 0.75rem 1rem;
    }
}