/* ===== CSS Variables ===== */
:root {
    /* Colors - Dark Theme */
    --bg-primary: #0f1117;
    --bg-secondary: #161b22;
    --bg-tertiary: #1c2128;
    --bg-hover: #21262d;
    --bg-active: #2d333b;
    
    --text-primary: #e6edf3;
    --text-secondary: #8b949e;
    --text-tertiary: #6e7681;
    
    --accent-primary: #7dd3fc;
    --accent-secondary: #a78bfa;
    --accent-success: #3fb950;
    --accent-warning: #f59e0b;
    --accent-danger: #f85149;
    
    --border-color: #30363d;
    --border-hover: #484f58;
    
    /* Spacing */
    --spacing-xs: 0.25rem;
    --spacing-sm: 0.5rem;
    --spacing-md: 1rem;
    --spacing-lg: 1.5rem;
    --spacing-xl: 2rem;
    
    /* Border radius */
    --radius-sm: 4px;
    --radius-md: 6px;
    --radius-lg: 8px;
    --radius-xl: 12px;
    
    /* Transitions */
    --transition-fast: 0.15s ease;
    --transition-normal: 0.25s ease;
    --transition-slow: 0.35s ease;
    
    /* Shadows */
    --shadow-sm: 0 1px 3px rgba(0, 0, 0, 0.3);
    --shadow-md: 0 4px 6px rgba(0, 0, 0, 0.4);
    --shadow-lg: 0 10px 15px rgba(0, 0, 0, 0.5);
    --shadow-xl: 0 20px 25px rgba(0, 0, 0, 0.6);
    
    /* Fonts */
    --font-mono: 'JetBrains Mono', 'Fira Code', 'Cascadia Code', 'Consolas', monospace;
    --font-sans: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, sans-serif;
}

/* Light Theme */
.theme-light {
    --bg-primary: #ffffff;
    --bg-secondary: #f6f8fa;
    --bg-tertiary: #eaeef2;
    --bg-hover: #e7ecf0;
    --bg-active: #dde3e9;
    
    --text-primary: #1f2328;
    --text-secondary: #57606a;
    --text-tertiary: #656d76;
    
    --border-color: #d0d7de;
    --border-hover: #b1bac4;
    
    --shadow-sm: 0 1px 3px rgba(0, 0, 0, 0.1);
    --shadow-md: 0 4px 6px rgba(0, 0, 0, 0.1);
    --shadow-lg: 0 10px 15px rgba(0, 0, 0, 0.15);
    --shadow-xl: 0 20px 25px rgba(0, 0, 0, 0.2);
}

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

html, body {
    height: 100%;
    font-family: var(--font-sans);
    font-size: 14px;
    line-height: 1.6;
    background: var(--bg-primary);
    color: var(--text-primary);
    overflow: hidden;
}

/* ===== Auth Page ===== */
.auth-page {
    display: flex;
    align-items: center;
    justify-content: center;
    min-height: 100vh;
    background: linear-gradient(135deg, var(--bg-primary) 0%, var(--bg-secondary) 100%);
    overflow: auto;
}

.auth-container {
    width: 100%;
    max-width: 420px;
    padding: var(--spacing-md);
}

.auth-box {
    background: var(--bg-secondary);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-xl);
    padding: var(--spacing-xl);
    box-shadow: var(--shadow-xl);
}

.auth-header {
    text-align: center;
    margin-bottom: var(--spacing-xl);
}

.auth-header h1 {
    font-size: 2rem;
    margin-bottom: var(--spacing-sm);
    color: var(--text-primary);
}

.auth-header p {
    color: var(--text-secondary);
    font-size: 0.95rem;
}

.auth-tabs {
    display: flex;
    gap: var(--spacing-sm);
    margin-bottom: var(--spacing-lg);
    border-bottom: 1px solid var(--border-color);
}

.tab-btn {
    flex: 1;
    padding: var(--spacing-md);
    border: none;
    background: transparent;
    color: var(--text-secondary);
    font-size: 0.95rem;
    font-weight: 500;
    cursor: pointer;
    transition: var(--transition-fast);
    border-bottom: 2px solid transparent;
}

.tab-btn.active {
    color: var(--accent-primary);
    border-bottom-color: var(--accent-primary);
}

.auth-form {
    display: none;
}

.auth-form.active {
    display: block;
}

.form-group {
    margin-bottom: var(--spacing-lg);
}

.form-group label {
    display: block;
    margin-bottom: var(--spacing-sm);
    color: var(--text-secondary);
    font-size: 0.9rem;
    font-weight: 500;
}

.form-group input {
    width: 100%;
    padding: var(--spacing-md);
    background: var(--bg-tertiary);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    color: var(--text-primary);
    font-size: 0.95rem;
    transition: var(--transition-fast);
}

.form-group input:focus {
    outline: none;
    border-color: var(--accent-primary);
    box-shadow: 0 0 0 3px rgba(125, 211, 252, 0.1);
}

.form-group small {
    display: block;
    margin-top: var(--spacing-xs);
    color: var(--text-tertiary);
    font-size: 0.85rem;
}

.alert {
    padding: var(--spacing-md);
    border-radius: var(--radius-md);
    margin-bottom: var(--spacing-lg);
    font-size: 0.9rem;
}

.alert-error {
    background: rgba(248, 81, 73, 0.1);
    border: 1px solid rgba(248, 81, 73, 0.3);
    color: var(--accent-danger);
}

.alert-success {
    background: rgba(63, 185, 80, 0.1);
    border: 1px solid rgba(63, 185, 80, 0.3);
    color: var(--accent-success);
}

/* ===== Buttons ===== */
.btn {
    display: inline-flex;
    align-items: center;
    gap: var(--spacing-sm);
    padding: var(--spacing-md) var(--spacing-lg);
    border: none;
    border-radius: var(--radius-md);
    font-size: 0.9rem;
    font-weight: 500;
    cursor: pointer;
    transition: var(--transition-fast);
    text-decoration: none;
}

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

.btn-primary:hover {
    background: #5ec4f7;
    transform: translateY(-1px);
    box-shadow: var(--shadow-md);
}

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

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

.btn-block {
    width: 100%;
    justify-content: center;
}

.btn-icon {
    padding: var(--spacing-sm);
    background: transparent;
    border: none;
    color: var(--text-secondary);
    cursor: pointer;
    border-radius: var(--radius-sm);
    transition: var(--transition-fast);
    display: inline-flex;
    align-items: center;
    justify-content: center;
}

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

/* ===== App Container ===== */
.app-container {
    display: flex;
    height: 100vh;
    overflow: hidden;
}

/* ===== Sidebar ===== */
.sidebar {
    width: 280px;
    background: var(--bg-secondary);
    border-right: 1px solid var(--border-color);
    display: flex;
    flex-direction: column;
    flex-shrink: 0;
}

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

.app-title {
    font-size: 1.2rem;
    font-weight: 600;
}

.search-box {
    padding: var(--spacing-md) var(--spacing-lg);
    border-bottom: 1px solid var(--border-color);
    position: relative;
}

.search-box svg {
    position: absolute;
    left: calc(var(--spacing-lg) + var(--spacing-sm));
    top: 50%;
    transform: translateY(-50%);
    color: var(--text-tertiary);
}

.search-box input {
    width: 100%;
    padding: var(--spacing-sm) var(--spacing-md) var(--spacing-sm) 2.5rem;
    background: var(--bg-tertiary);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    color: var(--text-primary);
    font-size: 0.9rem;
}

.search-box input:focus {
    outline: none;
    border-color: var(--accent-primary);
}

.sidebar-nav {
    padding: var(--spacing-md) var(--spacing-sm);
    border-bottom: 1px solid var(--border-color);
}

.nav-item {
    display: flex;
    align-items: center;
    gap: var(--spacing-md);
    width: 100%;
    padding: var(--spacing-sm) var(--spacing-md);
    background: transparent;
    border: none;
    border-radius: var(--radius-md);
    color: var(--text-secondary);
    font-size: 0.9rem;
    cursor: pointer;
    transition: var(--transition-fast);
    margin-bottom: var(--spacing-xs);
}

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

.nav-item.active {
    background: var(--bg-active);
    color: var(--accent-primary);
}

.nav-item svg {
    flex-shrink: 0;
}

.nav-item span:first-of-type {
    flex: 1;
    text-align: left;
}

.badge {
    background: var(--bg-active);
    color: var(--text-tertiary);
    padding: 2px 6px;
    border-radius: 10px;
    font-size: 0.75rem;
    font-weight: 600;
}

.sidebar-divider {
    height: 1px;
    background: var(--border-color);
    margin: var(--spacing-sm) 0;
}

.folders-section,
.tags-section {
    padding: var(--spacing-md) var(--spacing-sm);
    overflow-y: auto;
    flex: 1;
}

.section-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: var(--spacing-sm) var(--spacing-md);
    margin-bottom: var(--spacing-sm);
    color: var(--text-tertiary);
    font-size: 0.75rem;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.5px;
}

.folder-tree {
    padding-left: var(--spacing-sm);
}

.folder-item {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    padding: var(--spacing-sm) var(--spacing-md);
    border-radius: var(--radius-md);
    cursor: pointer;
    transition: var(--transition-fast);
    color: var(--text-secondary);
    font-size: 0.9rem;
}

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

.folder-item.active {
    background: var(--bg-active);
    color: var(--accent-primary);
}

.folder-icon {
    font-size: 1rem;
}

.folder-name {
    flex: 1;
}

.folder-count {
    font-size: 0.75rem;
    color: var(--text-tertiary);
}

.tags-list {
    display: flex;
    flex-wrap: wrap;
    gap: var(--spacing-sm);
    padding: 0 var(--spacing-sm);
}

.tag-item {
    display: inline-flex;
    align-items: center;
    gap: var(--spacing-xs);
    padding: var(--spacing-xs) var(--spacing-sm);
    background: var(--bg-tertiary);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-sm);
    color: var(--tag-color, var(--accent-primary));
    font-size: 0.85rem;
    cursor: pointer;
    transition: var(--transition-fast);
}

.tag-item:hover {
    background: var(--bg-hover);
    border-color: var(--tag-color, var(--accent-primary));
}

.tag-count {
    font-size: 0.75rem;
    opacity: 0.7;
}

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

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

.user-info {
    flex: 1;
    display: flex;
    align-items: center;
    gap: var(--spacing-md);
}

.user-avatar {
    width: 36px;
    height: 36px;
    background: var(--accent-primary);
    color: var(--bg-primary);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-weight: 600;
    font-size: 1rem;
}

.user-details {
    flex: 1;
    overflow: hidden;
}

.user-name {
    font-size: 0.9rem;
    font-weight: 500;
    color: var(--text-primary);
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
}

.user-email {
    font-size: 0.75rem;
    color: var(--text-tertiary);
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
}

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

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

.content-header h2 {
    font-size: 1.5rem;
    font-weight: 600;
}

.view-controls {
    display: flex;
    gap: var(--spacing-sm);
}

.notes-list-container {
    flex: 1;
    display: flex;
    flex-direction: column;
    overflow: hidden;
}

.notes-list {
    flex: 1;
    padding: var(--spacing-lg);
    overflow-y: auto;
}

.notes-list.view-list {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-md);
}

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

.note-card {
    background: var(--bg-secondary);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-lg);
    padding: var(--spacing-lg);
    cursor: pointer;
    transition: var(--transition-fast);
}

.note-card:hover {
    border-color: var(--border-hover);
    box-shadow: var(--shadow-md);
    transform: translateY(-2px);
}

.note-card-header {
    display: flex;
    align-items: flex-start;
    justify-content: space-between;
    margin-bottom: var(--spacing-md);
}

.note-title {
    font-size: 1.1rem;
    font-weight: 600;
    color: var(--text-primary);
    margin: 0;
}

.note-meta {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    color: var(--text-tertiary);
    font-size: 0.85rem;
    margin-top: var(--spacing-sm);
}

.note-preview {
    color: var(--text-secondary);
    font-size: 0.9rem;
    line-height: 1.5;
    margin-bottom: var(--spacing-md);
    display: -webkit-box;
    -webkit-line-clamp: 3;
    -webkit-box-orient: vertical;
    overflow: hidden;
}

.note-tags {
    display: flex;
    flex-wrap: wrap;
    gap: var(--spacing-xs);
}

.note-tag {
    padding: 2px 8px;
    background: var(--bg-tertiary);
    border-radius: var(--radius-sm);
    color: var(--accent-primary);
    font-size: 0.75rem;
}

/* ===== Note Editor ===== */
.note-editor-container {
    flex: 1;
    display: flex;
    flex-direction: column;
    overflow: hidden;
}

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

.editor-title-input {
    flex: 1;
    padding: var(--spacing-md);
    background: transparent;
    border: 1px solid transparent;
    border-radius: var(--radius-md);
    color: var(--text-primary);
    font-size: 1.5rem;
    font-weight: 600;
    transition: var(--transition-fast);
}

.editor-title-input:focus {
    outline: none;
    background: var(--bg-secondary);
    border-color: var(--border-color);
}

.editor-toolbar {
    padding: var(--spacing-md) var(--spacing-lg);
    border-bottom: 1px solid var(--border-color);
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    background: var(--bg-secondary);
}

.editor-content {
    flex: 1;
    display: flex;
    overflow: hidden;
}

.editor-pane {
    flex: 1;
    display: flex;
    flex-direction: column;
    overflow: hidden;
}

.editor-pane.split {
    border-right: 1px solid var(--border-color);
}

.editor-textarea {
    flex: 1;
    padding: var(--spacing-xl);
    background: var(--bg-primary);
    border: none;
    color: var(--text-primary);
    font-family: var(--font-mono);
    font-size: 0.95rem;
    line-height: 1.8;
    resize: none;
    overflow-y: auto;
}

.editor-textarea:focus {
    outline: none;
}

.preview-pane {
    flex: 1;
    padding: var(--spacing-xl);
    overflow-y: auto;
    background: var(--bg-primary);
}

/* ===== Right Panel ===== */
.right-panel {
    width: 320px;
    background: var(--bg-secondary);
    border-left: 1px solid var(--border-color);
    display: flex;
    flex-direction: column;
    flex-shrink: 0;
}

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

.panel-header h3 {
    font-size: 1rem;
    font-weight: 600;
}

.preview-content {
    flex: 1;
    padding: var(--spacing-lg);
    overflow-y: auto;
}

.preview-placeholder {
    display: flex;
    align-items: center;
    justify-content: center;
    height: 100%;
    color: var(--text-tertiary);
    text-align: center;
}

/* ===== Graph View ===== */
.graph-container {
    flex: 1;
    display: flex;
    flex-direction: column;
    overflow: hidden;
}

#graph-canvas {
    flex: 1;
    background: var(--bg-primary);
}

/* ===== Modals ===== */
.modal-overlay {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: rgba(0, 0, 0, 0.7);
    display: flex;
    align-items: center;
    justify-content: center;
    z-index: 1000;
}

.modal {
    position: fixed;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    z-index: 1001;
}

.modal-content {
    background: var(--bg-secondary);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-xl);
    width: 90vw;
    max-width: 500px;
    box-shadow: var(--shadow-xl);
}

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

.modal-header h3 {
    font-size: 1.2rem;
    font-weight: 600;
}

.modal-close {
    font-size: 1.5rem;
    color: var(--text-tertiary);
}

.modal-body {
    padding: var(--spacing-lg);
}

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

.input-large {
    width: 100%;
    padding: var(--spacing-md);
    background: var(--bg-tertiary);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    color: var(--text-primary);
    font-size: 1rem;
    margin-bottom: var(--spacing-md);
}

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

.select {
    width: 100%;
    padding: var(--spacing-md);
    background: var(--bg-tertiary);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    color: var(--text-primary);
    font-size: 0.9rem;
}

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

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

::-webkit-scrollbar-thumb {
    background: var(--bg-active);
    border-radius: var(--radius-sm);
}

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

/* ===== Responsive ===== */
@media (max-width: 768px) {
    .sidebar {
        position: absolute;
        left: -280px;
        top: 0;
        bottom: 0;
        z-index: 100;
        transition: left var(--transition-normal);
    }
    
    .sidebar.open {
        left: 0;
    }
    
    .right-panel {
        display: none;
    }
}

/* ===== Animations ===== */
@keyframes fadeIn {
    from {
        opacity: 0;
        transform: translateY(10px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.fade-in {
    animation: fadeIn var(--transition-normal);
}

/* ===== Markdown Preview Styles ===== */
.preview-content h1 {
    font-size: 2rem;
    margin-top: 1.5rem;
    margin-bottom: 1rem;
    font-weight: 700;
    color: var(--text-primary);
}

.preview-content h2 {
    font-size: 1.5rem;
    margin-top: 1.25rem;
    margin-bottom: 0.75rem;
    font-weight: 600;
    color: var(--text-primary);
}

.preview-content h3 {
    font-size: 1.25rem;
    margin-top: 1rem;
    margin-bottom: 0.5rem;
    font-weight: 600;
    color: var(--text-primary);
}

.preview-content p {
    margin-bottom: 1rem;
    line-height: 1.8;
}

.preview-content code {
    padding: 2px 6px;
    background: var(--bg-tertiary);
    border-radius: var(--radius-sm);
    font-family: var(--font-mono);
    font-size: 0.9em;
}

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

.preview-content pre code {
    padding: 0;
    background: transparent;
}

.preview-content blockquote {
    padding-left: var(--spacing-lg);
    border-left: 3px solid var(--accent-primary);
    color: var(--text-secondary);
    margin-bottom: 1rem;
}

.preview-content ul,
.preview-content ol {
    padding-left: 2rem;
    margin-bottom: 1rem;
}

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

.preview-content a {
    color: var(--accent-primary);
    text-decoration: none;
}

.preview-content a:hover {
    text-decoration: underline;
}

.preview-content img {
    max-width: 100%;
    border-radius: var(--radius-md);
    margin: 1rem 0;
}