:root {
    /* Dark Theme Colors */
    --bg-primary: #0f172a;
    --bg-secondary: #1e293b;
    --bg-tertiary: #334155;
    --text-primary: #f8fafc;
    --text-secondary: #cbd5e1;
    --text-muted: #94a3b8;
    --accent-primary: #8b5cf6;
    --accent-primary-glow: rgba(139, 92, 246, 0.15);
    --accent-secondary: #3b82f6;
    --accent-success: #10b981;
    --accent-danger: #ef4444;
    --border-subtle: rgba(148, 163, 184, 0.1);
    --border-strong: rgba(148, 163, 184, 0.2);
    
    /* UI Properties */
    --card-glow: 0 0 20px rgba(30, 41, 59, 0.5);
    --btn-glow: 0 0 15px rgba(139, 92, 246, 0.3);
    --input-glow: 0 0 0 2px rgba(139, 92, 246, 0.2);
    --rounded-lg: 1rem;
    --rounded-md: 0.6rem;
    --rounded-sm: 0.4rem;
    --transition-normal: all 0.2s ease;
    --transition-slow: all 0.3s ease;
  }
  
  * {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
  }
  
  body {
    font-family: 'Plus Jakarta Sans', -apple-system, BlinkMacSystemFont, sans-serif;
    background: radial-gradient(circle at top right, #1e293b, #0f172a);
    color: var(--text-primary);
    min-height: 100vh;
    line-height: 1.6;
    padding: 2rem 1rem;
  }
  
  h1, h2, h3, h4 {
    font-weight: 700;
    line-height: 1.2;
  }
  
  .container {
    max-width: 1000px;
    margin: 0 auto;
  }
  
  .main-card {
    position: relative;
    background: linear-gradient(to bottom, #1e293b, #0f172a);
    border-radius: var(--rounded-lg);
    overflow: hidden;
    box-shadow: var(--card-glow);
    border: 1px solid var(--border-subtle);
  }
  
  .card-gradient-border {
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 5px;
    background: linear-gradient(to right, var(--accent-primary), var(--accent-secondary));
  }
  
  .card-header {
    padding: 2.5rem 2.5rem 1.5rem;
    display: flex;
    align-items: center;
    justify-content: space-between;
    border-bottom: 1px solid var(--border-subtle);
  }
  
  .card-body {
    padding: 2rem 2.5rem;
  }
  
  .header-title {
    display: flex;
    align-items: center;
    gap: 1rem;
  }
  
  .logo {
    width: 40px;
    height: 40px;
    background: linear-gradient(135deg, var(--accent-primary), var(--accent-secondary));
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    color: white;
    font-size: 1.5rem;
    box-shadow: 0 0 15px rgba(139, 92, 246, 0.4);
  }
  
  .title {
    font-size: 1.75rem;
    background: linear-gradient(135deg, #f8fafc, #cbd5e1);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    letter-spacing: -0.02em;
  }
  
  .settings-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 2rem;
    margin-bottom: 2rem;
  }
  
  .form-group {
    margin-bottom: 1.25rem;
  }
  
  .form-label {
    display: block;
    font-weight: 600;
    margin-bottom: 0.5rem;
    font-size: 0.875rem;
    color: var(--text-secondary);
    text-transform: uppercase;
    letter-spacing: 0.05em;
  }
  
  .form-control {
    width: 100%;
    padding: 0.875rem 1rem;
    background-color: var(--bg-tertiary);
    border: 1px solid var(--border-subtle);
    border-radius: var(--rounded-md);
    color: var(--text-primary);
    font-family: inherit;
    font-size: 1rem;
    transition: var(--transition-normal);
  }
  
  .form-control:focus {
    outline: none;
    border-color: var(--accent-primary);
    box-shadow: var(--input-glow);
  }
  
  .form-control::placeholder {
    color: var(--text-muted);
  }
  
  textarea.form-control {
    min-height: 100px;
    resize: vertical;
  }
  
  .checkbox-container {
    display: flex;
    flex-direction: column;
    gap: 0.75rem;
    margin-bottom: 2rem;
  }
  
  .checkbox-wrapper {
    display: flex;
    align-items: center;
    cursor: pointer;
  }
  
  .checkbox-input {
    display: none;
  }
  
  .checkbox-display {
    width: 1.25rem;
    height: 1.25rem;
    border: 2px solid var(--border-strong);
    border-radius: var(--rounded-sm);
    margin-right: 0.75rem;
    position: relative;
    transition: var(--transition-normal);
    background: var(--bg-tertiary);
  }
  
  .checkbox-input:checked + .checkbox-display {
    background: var(--accent-primary);
    border-color: var(--accent-primary);
  }
  
  .checkbox-input:checked + .checkbox-display::after {
    content: "";
    position: absolute;
    top: 0.25rem;
    left: 0.4rem;
    width: 0.3rem;
    height: 0.6rem;
    border: solid white;
    border-width: 0 2px 2px 0;
    transform: rotate(45deg);
  }
  
  .checkbox-label {
    font-weight: 500;
    color: var(--text-secondary);
  }
  
  .btn-row {
    display: flex;
    flex-wrap: wrap;
    gap: 1rem;
    margin-bottom: 2rem;
  }
  
  .btn {
    position: relative;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    padding: 0.875rem 1.5rem;
    font-weight: 600;
    border-radius: var(--rounded-md);
    font-size: 0.875rem;
    letter-spacing: 0.01em;
    cursor: pointer;
    transition: var(--transition-normal);
    border: none;
    color: var(--text-primary);
    overflow: hidden;
    white-space: nowrap;
  }
  
  .btn::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: linear-gradient(90deg, rgba(255,255,255,0) 0%, rgba(255,255,255,0.1) 50%, rgba(255,255,255,0) 100%);
    transform: translateX(-100%);
    transition: transform 0.5s ease;
  }
  
  .btn:hover::before {
    transform: translateX(100%);
  }
  
  .btn-primary {
    background: linear-gradient(to right, var(--accent-primary), var(--accent-secondary));
    box-shadow: 0 2px 10px rgba(139, 92, 246, 0.3);
  }
  
  .btn-primary:hover:not(:disabled) {
    box-shadow: 0 4px 15px rgba(139, 92, 246, 0.5);
    transform: translateY(-1px);
  }
  
  .btn-danger {
    background-color: var(--accent-danger);
    box-shadow: 0 2px 10px rgba(239, 68, 68, 0.3);
  }
  
  .btn-danger:hover:not(:disabled) {
    box-shadow: 0 4px 15px rgba(239, 68, 68, 0.5);
    transform: translateY(-1px);
  }
  
  .btn:disabled {
    opacity: 0.5;
    cursor: not-allowed;
    transform: none !important;
    box-shadow: none !important;
  }
  
  .messages-container {
    position: relative;
    background-color: var(--bg-secondary);
    border-radius: var(--rounded-md);
    overflow: hidden;
    margin-bottom: 2rem;
  }
  
  .messages-heading {
    padding: 1rem;
    background-color: rgba(0, 0, 0, 0.1);
    font-weight: 600;
    color: var(--text-secondary);
    border-bottom: 1px solid var(--border-subtle);
    font-size: 0.875rem;
    letter-spacing: 0.01em;
  }
  
  .messages {
    height: 300px;
    overflow-y: auto;
    padding: 1rem;
  }
  
  .message {
    padding: 0.75rem 1rem;
    margin-bottom: 0.75rem;
    background-color: var(--bg-tertiary);
    border-radius: var(--rounded-md);
    color: var(--text-secondary);
    font-size: 0.875rem;
    border-left: 3px solid var(--accent-primary);
    animation: fadeIn 0.3s ease-out;
  }
  
  @keyframes fadeIn {
    from { opacity: 0; transform: translateY(5px); }
    to { opacity: 1; transform: translateY(0); }
  }
  
  .video-container {
    margin-top: 2rem;
  }
  
  .video-wrapper {
    position: relative;
    aspect-ratio: 16/9;
    background-color: rgba(0, 0, 0, 0.3);
    border-radius: var(--rounded-md);
    overflow: hidden;
    border: 1px solid var(--border-subtle);
    box-shadow: 0 4px 20px rgba(0, 0, 0, 0.2);
  }
  
  .video-wrapper video {
    width: 100%;
    height: 100%;
    object-fit: contain;
  }
  
  .video-overlay {
    position: absolute;
    top: 1rem;
    left: 1rem;
    background-color: rgba(15, 23, 42, 0.6);
    padding: 0.5rem 0.75rem;
    border-radius: var(--rounded-sm);
    font-size: 0.75rem;
    color: var(--text-secondary);
    backdrop-filter: blur(4px);
  }
  
  .hidden {
    display: none;
  }
  
  /* Scrollbar styling */
  ::-webkit-scrollbar {
    width: 8px;
    height: 8px;
  }
  
  ::-webkit-scrollbar-track {
    background: var(--bg-tertiary);
  }
  
  ::-webkit-scrollbar-thumb {
    background: var(--border-strong);
    border-radius: 4px;
  }
  
  ::-webkit-scrollbar-thumb:hover {
    background: var(--text-muted);
  }
  
  @media (max-width: 768px) {
    .settings-grid {
      grid-template-columns: 1fr;
    }
    
    .btn-row {
      flex-direction: column;
    }
    
    .btn {
      width: 100%;
    }
    
    .card-header,
    .card-body {
      padding: 1.5rem;
    }
  }
  
  /* Animations and effects */
  @keyframes glow {
    0%, 100% { box-shadow: 0 0 15px rgba(139, 92, 246, 0.3); }
    50% { box-shadow: 0 0 25px rgba(139, 92, 246, 0.5); }
  }
  
  .pulse {
    animation: glow 2s infinite;
  }