:root {
    /* Color Variables */
    --bg-primary: #f8f9fa;
    --bg-secondary: #e9ecef;
    --bg-tertiary: #dee2e6;
    --text-primary: #212529;
    --text-secondary: #495057;
    --accent-primary: #7048e8;
    --accent-secondary: #5a3cc0;
    --accent-tertiary: #8b6fe9;
    --success: #28a745;
    --warning: #ffc107;
    --danger: #dc3545;
    --info: #17a2b8;
    
    /* UI Elements */
    --card-bg: #ffffff;
    --input-bg: #ffffff;
    --border-color: #ced4da;
    
    /* Shadows */
    --shadow-sm: 0 2px 4px rgba(0, 0, 0, 0.05);
    --shadow-md: 0 4px 6px rgba(0, 0, 0, 0.1);
    --shadow-lg: 0 10px 15px rgba(0, 0, 0, 0.1);
    
    /* Spacing */
    --space-xs: 0.25rem;
    --space-sm: 0.5rem;
    --space-md: 1rem;
    --space-lg: 1.5rem;
    --space-xl: 2rem;
    
    /* Border Radius */
    --radius-sm: 0.25rem;
    --radius-md: 0.5rem;
    --radius-lg: 1rem;
    
    /* Transitions */
    --transition-fast: 150ms ease;
    --transition-normal: 300ms ease;
  }
  
  .dark-theme {
    --bg-primary: #121212;
    --bg-secondary: #1e1e1e;
    --bg-tertiary: #292929;
    --text-primary: #e9ecef;
    --text-secondary: #adb5bd;
    --card-bg: #242424;
    --input-bg: #1e1e1e;
    --border-color: #444444;
    
    /* Shadows in dark mode */
    --shadow-sm: 0 2px 4px 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, 0.4);
  }
  
  /* Base Styles */
  * {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
  }
  
  body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
    font-size: 1rem;
    line-height: 1.5;
    background: var(--bg-primary);
    color: var(--text-primary);
    transition: background-color var(--transition-normal), color var(--transition-normal);
    overflow: hidden;
    height: 100vh;
    width: 100vw;
  }
  
  .app-container {
    display: grid;
    grid-template-columns: 1fr;
    grid-template-rows: auto 1fr;
    height: 100vh;
  }
  
  /* Header Styles */
  header {
    background-color: var(--bg-secondary);
    padding: var(--space-md);
    display: flex;
    justify-content: space-between;
    align-items: center;
    box-shadow: var(--shadow-sm);
    z-index: 10;
  }
  
  .logo-container {
    display: flex;
    align-items: center;
    gap: var(--space-md);
  }
  
  .logo {
    height: 40px;
    width: auto;
  }
  
  .app-title {
    font-size: 1.5rem;
    font-weight: 600;
    margin: 0;
  }
  
  .header-controls {
    display: flex;
    gap: var(--space-md);
    align-items: center;
  }
  
  /* Main Content Area */
  .main-content {
    display: grid;
    grid-template-columns: 1fr 320px;
    height: 100%;
    overflow: hidden;
  }
  
  .canvas-container {
    position: relative;
    overflow: hidden;
  }
  
  /* Sidebar */
  .sidebar {
    background-color: var(--card-bg);
    border-left: 1px solid var(--border-color);
    overflow-y: auto;
    box-shadow: var(--shadow-md);
    transition: transform var(--transition-normal);
  }
  
  /* Tabs */
  .tab-navigation {
    display: flex;
    border-bottom: 1px solid var(--border-color);
    background-color: var(--bg-secondary);
  }
  
  .tab-button {
    padding: var(--space-md);
    flex: 1;
    background: none;
    border: none;
    border-bottom: 3px solid transparent;
    color: var(--text-secondary);
    font-weight: 500;
    cursor: pointer;
    transition: all var(--transition-fast);
  }
  
  .tab-button:hover {
    color: var(--accent-primary);
  }
  
  .tab-button.active {
    color: var(--accent-primary);
    border-bottom-color: var(--accent-primary);
  }
  
  .tab-content {
    display: none;
    padding: var(--space-md);
  }
  
  .tab-content.active {
    display: block;
  }
  
  /* Form Controls */
  .form-group {
    margin-bottom: var(--space-md);
  }
  
  label {
    display: block;
    margin-bottom: var(--space-xs);
    color: var(--text-secondary);
    font-weight: 500;
  }
  
  input[type="text"],
  input[type="number"],
  select {
    width: 100%;
    padding: var(--space-sm);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-sm);
    background-color: var(--input-bg);
    color: var(--text-primary);
    transition: all var(--transition-fast);
  }
  
  input[type="text"]:focus,
  input[type="number"]:focus,
  select:focus {
    outline: none;
    border-color: var(--accent-primary);
    box-shadow: 0 0 0 2px rgba(112, 72, 232, 0.2);
  }
  
  /* Buttons */
  .btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    padding: var(--space-sm) var(--space-md);
    border: none;
    border-radius: var(--radius-sm);
    font-weight: 500;
    cursor: pointer;
    transition: all var(--transition-fast);
    background-color: var(--bg-tertiary);
    color: var(--text-primary);
  }
  
  .btn-primary {
    background-color: var(--accent-primary);
    color: white;
  }
  
  .btn-primary:hover {
    background-color: var(--accent-secondary);
  }
  
  .btn i {
    margin-right: var(--space-xs);
  }
  
  /* Switch/Toggle */
  .switch-container {
    display: flex;
    align-items: center;
    margin-bottom: var(--space-md);
  }
  
  .switch {
    position: relative;
    display: inline-block;
    width: 50px;
    height: 24px;
    margin-right: var(--space-sm);
  }
  
  .switch input {
    opacity: 0;
    width: 0;
    height: 0;
  }
  
  .slider {
    position: absolute;
    cursor: pointer;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background-color: var(--bg-tertiary);
    transition: .4s;
    border-radius: 34px;
  }
  
  .slider:before {
    position: absolute;
    content: "";
    height: 16px;
    width: 16px;
    left: 4px;
    bottom: 4px;
    background-color: white;
    transition: .4s;
    border-radius: 50%;
  }
  
  input:checked + .slider {
    background-color: var(--accent-primary);
  }
  
  input:checked + .slider:before {
    transform: translateX(26px);
  }
  
  /* Section styles */
  .section {
    margin-bottom: var(--space-lg);
  }
  
  .section-title {
    font-size: 1.1rem;
    margin-bottom: var(--space-md);
    padding-bottom: var(--space-xs);
    border-bottom: 1px solid var(--border-color);
  }
  
  /* File upload styling */
  .file-upload {
    display: inline-block;
    position: relative;
    margin-bottom: var(--space-md);
  }
  
  .file-upload-btn {
    display: inline-block;
    padding: var(--space-sm) var(--space-md);
    background-color: var(--accent-primary);
    color: white;
    border-radius: var(--radius-sm);
    cursor: pointer;
    transition: background-color var(--transition-fast);
  }
  
  .file-upload-btn:hover {
    background-color: var(--accent-secondary);
  }
  
  .file-upload input[type="file"] {
    position: absolute;
    left: 0;
    top: 0;
    opacity: 0;
    width: 0;
    height: 0;
  }
  
  /* Toast notifications */
  .toast-container {
    position: fixed;
    bottom: var(--space-lg);
    right: var(--space-lg);
    z-index: 1000;
  }
  
  .toast {
    padding: var(--space-md);
    background-color: var(--card-bg);
    border-radius: var(--radius-sm);
    box-shadow: var(--shadow-lg);
    margin-top: var(--space-sm);
    display: flex;
    align-items: center;
    min-width: 250px;
    transform: translateX(100%);
    animation: slide-in 0.3s forwards;
  }
  
  .toast.success {
    border-left: 4px solid var(--success);
  }
  
  .toast.error {
    border-left: 4px solid var(--danger);
  }
  
  @keyframes slide-in {
    to { transform: translateX(0); }
  }
  
  /* Theme toggle button */
  .theme-toggle {
    background: none;
    border: none;
    cursor: pointer;
    color: var(--text-primary);
    font-size: 1.2rem;
    padding: var(--space-xs);
  }
  
  /* Responsive styles */
/* Replace the existing media query with this */
@media (max-width: 768px) {
  .main-content {
      grid-template-columns: 1fr;
      grid-template-rows: 60% 40%;
  }
  
  .sidebar {
      position: relative;
      width: 100%;
      height: 100%;
      transform: none;
      border-left: none;
      border-top: 1px solid var(--border-color);
  }
  
  .canvas-container {
      height: 100%;
  }
}