:root {
    --primary-color: #4f46e5;
    --primary-hover: #4338ca;
    --secondary-color: #f3f4f6;
    --text-color: #1f2937;
    --text-secondary: #6b7280;
    --background-color: #ffffff;
    --card-background: #ffffff;
    --border-color: #e5e7eb;
    --shadow-color: rgba(0, 0, 0, 0.1);
    --user-message-bg: #4f46e5;
    --user-message-color: #ffffff;
    --bot-message-bg: #f3f4f6;
    --bot-message-color: #1f2937;
    --transition-speed: 0.3s;
    --border-radius: 0.5rem;
    --warning-color: #f59e0b;
    --danger-color: #ef4444;
    --success-color: #10b981;
  }
  
  .dark-theme {
    --primary-color: #6366f1;
    --primary-hover: #818cf8;
    --secondary-color: #374151;
    --text-color: #f9fafb;
    --text-secondary: #d1d5db;
    --background-color: #111827;
    --card-background: #1f2937;
    --border-color: #374151;
    --shadow-color: rgba(0, 0, 0, 0.3);
    --user-message-bg: #6366f1;
    --user-message-color: #ffffff;
    --bot-message-bg: #374151;
    --bot-message-color: #f9fafb;
    --warning-color: #fbbf24;
    --danger-color: #f87171;
    --success-color: #34d399;
  }
  
  * {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
  }
  
  body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    background-color: var(--background-color);
    color: var(--text-color);
    line-height: 1.6;
    transition: background-color var(--transition-speed), color var(--transition-speed);
  }
  
  .app-container {
    display: flex;
    flex-direction: column;
    height: 100vh;
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 1rem;
  }
  
  /* Header Styles */
  .app-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 1rem 0;
    border-bottom: 1px solid var(--border-color);
  }
  
  .header-controls {
    display: flex;
    gap: 0.5rem;
  }

  .creator button {
    background-color: #1f2937;
    padding: 10px;
    border: none;
    border-radius: var(--border-radius);
    color: #ffffff;
    cursor: pointer;
  }

  .creator button:hover {
    background-color: #374754;
  }

  .creator a {
    color: #ffffff;
    text-decoration: none;
  }
  
  .icon-btn {
    background: transparent;
    border: 1px solid var(--border-color);
    border-radius: var(--border-radius);
    width: 2.5rem;
    height: 2.5rem;
    display: flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    transition: background-color var(--transition-speed);
    color: var(--text-color);
  }
  
  .icon-btn:hover {
    background-color: var(--secondary-color);
  }
  
  /* Limit Indicator */
  .limit-indicator {
    padding: 0.5rem 0;
    text-align: center;
    font-size: 0.875rem;
    color: var(--text-secondary);
    border-bottom: 1px solid var(--border-color);
  }
  
  .limit-warning {
    color: var(--warning-color);
  }
  
  .limit-danger {
    color: var(--danger-color);
  }
  
  /* Chat Container */
  .chat-container {
    flex: 1;
    overflow-y: auto;
    padding: 1rem 0;
    scroll-behavior: smooth;
  }
  
  .welcome-screen {
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    height: 100%;
    text-align: center;
    padding: 0 1rem;
  }
  
  .welcome-screen h2 {
    margin-bottom: 1rem;
    font-size: 1.5rem;
  }
  
  .welcome-screen p {
    margin-bottom: 1rem;
    color: var(--text-secondary);
    max-width: 500px;
  }
  
  #limit-notice {
    color: var(--warning-color);
    font-weight: 500;
    margin-bottom: 2rem;
  }
  
  .messages {
    display: flex;
    flex-direction: column;
    gap: 1rem;
  }
  
  .message {
    display: flex;
    align-items: flex-start;
    gap: 0.75rem;
    animation: fadeIn 0.3s ease-out;
  }
  
  .message.user {
    flex-direction: row-reverse;
  }
  
  .avatar {
    width: 2rem;
    height: 2rem;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-weight: bold;
    font-size: 0.75rem;
  }
  
  .user .avatar {
    background-color: var(--primary-color);
    color: white;
  }
  
  .bot .avatar {
    background-color: var(--secondary-color);
    color: var(--text-color);
  }
  
  .message-bubble {
    max-width: 80%;
    padding: 0.75rem 1rem;
    border-radius: var(--border-radius);
    animation: slideIn 0.3s ease-out;
  }
  
  .user .message-bubble {
    background-color: var(--user-message-bg);
    color: var(--user-message-color);
    border-top-right-radius: 0;
  }
  
  .bot .message-bubble {
    background-color: var(--bot-message-bg);
    color: var(--bot-message-color);
    border-top-left-radius: 0;
  }
  
  .typing-indicator {
    display: flex;
    align-items: center;
  }
  
  .typing-dot {
    width: 0.5rem;
    height: 0.5rem;
    border-radius: 50%;
    background-color: var(--text-secondary);
    margin: 0 0.1rem;
    animation: bounce 1s infinite;
  }
  
  .typing-dot:nth-child(2) {
    animation-delay: 0.2s;
  }
  
  .typing-dot:nth-child(3) {
    animation-delay: 0.4s;
  }
  
  /* Suggestion Chips */
  .suggestion-bar {
    display: flex;
    flex-wrap: wrap;
    gap: 0.5rem;
    padding: 0.5rem 0;
    border-top: 1px solid var(--border-color);
    display: none;
  }
  
  .suggestion-chips {
    display: flex;
    flex-wrap: wrap;
    gap: 0.5rem;
    justify-content: center;
  }
  
  .suggestion-chip {
    background-color: var(--secondary-color);
    color: var(--text-color);
    border: none;
    border-radius: 1rem;
    padding: 0.5rem 1rem;
    font-size: 0.875rem;
    cursor: pointer;
    transition: background-color var(--transition-speed);
  }
  
  .suggestion-chip:hover {
    background-color: var(--border-color);
  }
  
  .suggestion-chip:disabled {
    opacity: 0.5;
    cursor: not-allowed;
  }
  
  /* Input Container */
  .input-container {
    padding: 1rem 0;
    border-top: 1px solid var(--border-color);
  }
  
  #chat-form {
    display: flex;
    gap: 0.5rem;
  }
  
  #user-input {
    flex: 1;
    padding: 0.75rem 1rem;
    border: 1px solid var(--border-color);
    border-radius: var(--border-radius);
    background-color: var(--card-background);
    color: var(--text-color);
    font-size: 1rem;
    transition: border-color var(--transition-speed);
  }
  
  #user-input:focus {
    outline: none;
    border-color: var(--primary-color);
  }
  
  #user-input:disabled {
    opacity: 0.7;
    cursor: not-allowed;
  }
  
  /* Modal Styles */
  .modal {
    display: none;
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background-color: rgba(0, 0, 0, 0.5);
    z-index: 1000;
    align-items: center;
    justify-content: center;
  }
  
  .modal.active {
    display: flex;
    animation: fadeIn 0.3s ease-out;
  }
  
  .modal-content {
    background-color: var(--card-background);
    border-radius: var(--border-radius);
    width: 90%;
    max-width: 500px;
    box-shadow: 0 4px 6px var(--shadow-color);
    animation: slideUp 0.3s ease-out;
  }
  
  .modal-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 1rem;
    border-bottom: 1px solid var(--border-color);
  }
  
  .close-btn {
    background: transparent;
    border: none;
    font-size: 1.5rem;
    cursor: pointer;
    color: var(--text-color);
  }
  
  .modal-body {
    padding: 1rem;
  }
  
  /* Voice Input Styles */
  .transcript-box {
    min-height: 100px;
    border: 1px solid var(--border-color);
    border-radius: var(--border-radius);
    padding: 0.75rem;
    margin-bottom: 1rem;
    background-color: var(--background-color);
    color: var(--text-color);
  }
  
  .voice-controls {
    display: flex;
    justify-content: space-between;
  }
  
  .primary-btn {
    background-color: var(--primary-color);
    color: white;
    border: none;
    border-radius: var(--border-radius);
    padding: 0.5rem 1rem;
    cursor: pointer;
    transition: background-color var(--transition-speed);
    display: flex;
    align-items: center;
    gap: 0.5rem;
  }
  
  .primary-btn:hover {
    background-color: var(--primary-hover);
  }
  
  .primary-btn:disabled {
    background-color: var(--border-color);
    cursor: not-allowed;
  }
  
  .primary-btn.recording {
    background-color: var(--danger-color);
  }
  
  /* Calculator Styles */
  .calculator {
    width: 100%;
  }
  
  .calculator-display {
    width: 100%;
    padding: 0.75rem;
    margin-bottom: 0.5rem;
    text-align: right;
    font-size: 1.25rem;
    border: 1px solid var(--border-color);
    border-radius: var(--border-radius);
    background-color: var(--background-color);
    color: var(--text-color);
  }
  
  .calculator-buttons {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 0.5rem;
  }
  
  .calc-btn {
    padding: 0.75rem;
    border: 1px solid var(--border-color);
    border-radius: var(--border-radius);
    background-color: var(--card-background);
    color: var(--text-color);
    font-size: 1rem;
    cursor: pointer;
    transition: background-color var(--transition-speed);
  }
  
  .calc-btn:hover {
    background-color: var(--secondary-color);
  }
  
  .calc-btn.operator {
    background-color: var(--secondary-color);
  }
  
  .calc-btn.equals {
    background-color: var(--primary-color);
    color: white;
  }
  
  .calc-btn.equals:hover {
    background-color: var(--primary-hover);
  }
  
  .calc-btn.clear, .calc-btn.backspace {
    grid-column: span 1;
  }
  
  .calc-btn.insert-result {
    grid-column: span 2;
    background-color: var(--primary-color);
    color: white;
  }
  
  .calc-btn.insert-result:hover {
    background-color: var(--primary-hover);
  }
  
  /* Language Modal Styles */
  .language-options {
    display: flex;
    flex-direction: column;
    gap: 1rem;
  }
  
  .language-option {
    display: flex;
    align-items: center;
    gap: 1rem;
    padding: 1rem;
    border: 1px solid var(--border-color);
    border-radius: var(--border-radius);
    background-color: var(--card-background);
    cursor: pointer;
    transition: background-color var(--transition-speed);
  }
  
  .language-option:hover {
    background-color: var(--secondary-color);
  }
  
  .language-option.active {
    border-color: var(--primary-color);
    background-color: var(--secondary-color);
  }
  
  .language-flag {
    font-size: 1.5rem;
  }
  
  .language-name {
    font-size: 1rem;
    font-weight: 500;
  }
  
  /* Animations */
  @keyframes fadeIn {
    from { opacity: 0; }
    to { opacity: 1; }
  }
  
  @keyframes slideIn {
    from { 
      opacity: 0;
      transform: translateY(10px);
    }
    to { 
      opacity: 1;
      transform: translateY(0);
    }
  }
  
  @keyframes slideUp {
    from { 
      opacity: 0;
      transform: translateY(20px);
    }
    to { 
      opacity: 1;
      transform: translateY(0);
    }
  }
  
  @keyframes bounce {
    0%, 100% { transform: translateY(0); }
    50% { transform: translateY(-5px); }
  }
  
  @keyframes pulse {
    0% { transform: scale(1); }
    50% { transform: scale(1.05); }
    100% { transform: scale(1); }
  }
  
  .language-changed {
    animation: pulse 0.5s ease-in-out;
  }
  
  /* Responsive Design */
  @media (max-width: 768px) {
    .app-header h1 {
      font-size: 1.25rem;
    }
    
    .icon-btn {
      width: 2rem;
      height: 2rem;
    }
    
    .message-bubble {
      max-width: 85%;
    }
  }
  
  @media (max-width: 480px) {
    header {
      flex-direction: column;
      gap: 1rem;
    }
    .message-bubble {
        max-width: 80%;
        margin-left: 1px;
        margin-right: 15px;
    }
    .app-container {
      padding: 0 0.5rem;
    }
    
    .message-bubble {
      max-width: 90%;
    }
    
    .calculator-buttons {
      gap: 0.25rem;
    }
    
    .calc-btn {
      padding: 0.5rem;
      font-size: 0.875rem;
    }
  }