/* CSS Custom Properties for Theming */
:root {
  /* Primary Colors */
  --primary-color: #1877f2;
  --primary-hover: #166fe5;
  --primary-light: #e3f2fd;
  
  /* Secondary Colors */
  --secondary-color: #42a5f5;
  --accent-color: #00c853;
  --warning-color: #ff9800;
  --error-color: #f44336;
  
  /* Background Colors */
  --bg-primary: #ffffff;
  --bg-secondary: #f8f9fa;
  --bg-tertiary: #e9ecef;
  --bg-overlay: rgba(0, 0, 0, 0.5);
  
  /* Text Colors */
  --text-primary: #212529;
  --text-secondary: #6c757d;
  --text-muted: #adb5bd;
  --text-inverse: #ffffff;
  
  /* Message Colors */
  --msg-user-bg: #1877f2;
  --msg-user-text: #ffffff;
  --msg-bot-bg: #e9ecef;
  --msg-bot-text: #212529;
  
  /* Border Colors */
  --border-color: #dee2e6;
  --border-focus: #1877f2;
  
  /* Shadows */
  --shadow-sm: 0 1px 3px rgba(0, 0, 0, 0.1);
  --shadow-md: 0 4px 12px rgba(0, 0, 0, 0.15);
  --shadow-lg: 0 8px 24px rgba(0, 0, 0, 0.2);
  
  /* Spacing */
  --spacing-xs: 0.25rem;
  --spacing-sm: 0.5rem;
  --spacing-md: 1rem;
  --spacing-lg: 1.5rem;
  --spacing-xl: 2rem;
  --spacing-xxl: 3rem;
  
  /* Typography */
  --font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, sans-serif;
  --font-size-xs: 0.75rem;
  --font-size-sm: 0.875rem;
  --font-size-md: 1rem;
  --font-size-lg: 1.125rem;
  --font-size-xl: 1.25rem;
  --font-size-xxl: 1.5rem;
  
  /* Animation */
  --transition-fast: 0.15s ease-in-out;
  --transition-normal: 0.3s ease-in-out;
  --transition-slow: 0.5s ease-in-out;
  
  /* Z-index layers */
  --z-dropdown: 1000;
  --z-sticky: 1020;
  --z-fixed: 1030;
  --z-modal: 1040;
  --z-popover: 1050;
  --z-tooltip: 1060;
}

/* Reset and Base Styles */
* {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

html {
  font-size: 16px;
  scroll-behavior: smooth;
}

body {
  font-family: var(--font-family);
  font-size: var(--font-size-md);
  line-height: 1.5;
  color: var(--text-primary);
  background-color: var(--bg-primary);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  overflow-x: hidden;
}

/* Screen Reader Only */
.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border: 0;
}

/* Theme Toggle */
.theme-toggle {
  position: fixed;
  top: var(--spacing-md);
  right: var(--spacing-md);
  z-index: var(--z-fixed);
  width: 48px;
  height: 48px;
  border: none;
  border-radius: 50%;
  background: var(--bg-secondary);
  color: var(--text-primary);
  cursor: pointer;
  transition: all var(--transition-normal);
  box-shadow: var(--shadow-md);
  display: flex;
  align-items: center;
  justify-content: center;
}

.theme-toggle:hover {
  transform: scale(1.05);
  box-shadow: var(--shadow-lg);
}

.theme-toggle:focus {
  outline: 2px solid var(--border-focus);
  outline-offset: 2px;
}

.theme-icon {
  width: 20px;
  height: 20px;
  transition: opacity var(--transition-fast);
}

.dark-icon {
  position: absolute;
  opacity: 0;
}

/* Welcome Screen */
.welcome-screen {
  min-height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: var(--spacing-lg);
  background: linear-gradient(135deg, var(--primary-light), var(--bg-secondary));
}

.welcome-content {
  width: 100%;
  max-width: 400px;
  text-align: center;
  animation: fadeInUp 0.6s ease-out;
}

.business-logo-placeholder {
  width: 80px;
  height: 80px;
  margin: 0 auto var(--spacing-lg);
  border-radius: 50%;
  background: var(--primary-color);
  color: var(--text-inverse);
  display: flex;
  align-items: center;
  justify-content: center;
  box-shadow: var(--shadow-md);
}

.business-logo-placeholder svg {
  width: 40px;
  height: 40px;
}

.welcome-title {
  font-size: var(--font-size-xxl);
  font-weight: 700;
  margin-bottom: var(--spacing-md);
  color: var(--text-primary);
}

.welcome-subtitle {
  font-size: var(--font-size-lg);
  color: var(--text-secondary);
  margin-bottom: var(--spacing-xl);
}

.welcome-form {
  display: flex;
  flex-direction: column;
  gap: var(--spacing-lg);
}

.input-group {
  position: relative;
}

.input-group input {
  width: 100%;
  padding: var(--spacing-lg);
  font-size: var(--font-size-lg);
  border: 2px solid var(--border-color);
  border-radius: 12px;
  background: var(--bg-primary);
  color: var(--text-primary);
  transition: all var(--transition-normal);
}

.input-group input:focus {
  outline: none;
  border-color: var(--border-focus);
  box-shadow: 0 0 0 3px rgba(24, 119, 242, 0.1);
}

.input-group input.error {
  border-color: var(--error-color);
  animation: shake 0.3s ease-in-out;
}

.error-message {
  position: absolute;
  top: 100%;
  left: 0;
  font-size: var(--font-size-sm);
  color: var(--error-color);
  margin-top: var(--spacing-xs);
  opacity: 0;
  transform: translateY(-5px);
  transition: all var(--transition-normal);
}

.error-message.show {
  opacity: 1;
  transform: translateY(0);
}

/* Buttons */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: var(--spacing-sm);
  padding: var(--spacing-md) var(--spacing-lg);
  font-size: var(--font-size-md);
  font-weight: 600;
  text-decoration: none;
  border: none;
  border-radius: 8px;
  cursor: pointer;
  transition: all var(--transition-normal);
  position: relative;
  overflow: hidden;
}

.btn:focus {
  outline: 2px solid var(--border-focus);
  outline-offset: 2px;
}

.btn:disabled {
  opacity: 0.6;
  cursor: not-allowed;
}

.btn-primary {
  background: var(--primary-color);
  color: var(--text-inverse);
}

.btn-primary:hover:not(:disabled) {
  background: var(--primary-hover);
  transform: translateY(-1px);
  box-shadow: var(--shadow-md);
}

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

.btn-secondary:hover:not(:disabled) {
  background: var(--border-color);
}

.btn-large {
  padding: var(--spacing-lg) var(--spacing-xl);
  font-size: var(--font-size-lg);
  border-radius: 12px;
}

.btn-full {
  width: 100%;
}

.btn-icon {
  padding: var(--spacing-md);
  min-width: 44px;
  min-height: 44px;
}

.btn-fab {
  width: 48px;
  height: 48px;
  border-radius: 50%;
  padding: 0;
  background: var(--primary-color);
  color: var(--text-inverse);
  box-shadow: var(--shadow-md);
}

.btn-send {
  min-width: 48px;
  min-height: 48px;
  border-radius: 50%;
  background: var(--primary-color);
  color: var(--text-inverse);
  padding: 0;
}

.btn-send:disabled {
  background: var(--text-muted);
}

/* Chat Container */
.chat-container {
  display: none;
  height: 100vh;
  flex-direction: column;
  background: var(--bg-primary);
}

.chat-container.show {
  display: flex;
}

/* Chat Header */
.chat-header {
  background: var(--bg-primary);
  border-bottom: 1px solid var(--border-color);
  padding: var(--spacing-md) var(--spacing-lg);
  box-shadow: var(--shadow-sm);
  position: sticky;
  top: 0;
  z-index: var(--z-sticky);
}

.chat-header-content {
  display: flex;
  align-items: center;
  justify-content: space-between;
  max-width: 100%;
}

.business-info {
  display: flex;
  align-items: center;
  gap: var(--spacing-md);
  flex: 1;
  min-width: 0;
}

.business-logo-small {
  width: 40px;
  height: 40px;
  border-radius: 50%;
  background: var(--primary-color);
  color: var(--text-inverse);
  display: flex;
  align-items: center;
  justify-content: center;
  flex-shrink: 0;
}

.business-logo-small svg {
  width: 20px;
  height: 20px;
}

.business-details {
  flex: 1;
  min-width: 0;
}

.chat-title {
  font-size: var(--font-size-lg);
  font-weight: 600;
  color: var(--text-primary);
  margin: 0;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

.chat-subtitle {
  font-size: var(--font-size-sm);
  color: var(--text-secondary);
  margin: 0;
}

/* Messages Container */
.messages-container {
  flex: 1;
  position: relative;
  overflow: hidden;
  background: var(--bg-secondary);
}

.messages-list {
  height: 100%;
  overflow-y: auto;
  padding: var(--spacing-md);
  scroll-behavior: smooth;
}

/* Messages */
.message {
  display: flex;
  margin-bottom: var(--spacing-md);
  opacity: 0;
  transform: translateY(10px);
  animation: messageSlideIn 0.3s ease-out forwards;
}

.message.user {
  justify-content: flex-end;
}

.message.bot {
  justify-content: flex-start;
}

.message-bubble {
  max-width: 80%;
  padding: var(--spacing-md) var(--spacing-lg);
  border-radius: 18px;
  position: relative;
  word-wrap: break-word;
  hyphens: auto;
}

.message.user .message-bubble {
  background: var(--msg-user-bg);
  color: var(--msg-user-text);
  border-bottom-right-radius: 4px;
}

.message.bot .message-bubble {
  background: var(--msg-bot-bg);
  color: var(--msg-bot-text);
  border-bottom-left-radius: 4px;
}

.message-content {
  line-height: 1.4;
}

.message-timestamp {
  font-size: var(--font-size-xs);
  opacity: 0.7;
  margin-top: var(--spacing-xs);
  text-align: right;
}

.message.bot .message-timestamp {
  text-align: left;
}

/* Typing Indicator */
.typing-indicator {
  display: flex;
  align-items: center;
  gap: var(--spacing-sm);
  padding: var(--spacing-md) var(--spacing-lg);
  background: var(--msg-bot-bg);
  color: var(--msg-bot-text);
  border-radius: 18px;
  border-bottom-left-radius: 4px;
  max-width: 80px;
}

.typing-dots {
  display: flex;
  gap: 4px;
}

.typing-dot {
  width: 6px;
  height: 6px;
  border-radius: 50%;
  background: currentColor;
  opacity: 0.4;
  animation: typingPulse 1.4s infinite;
}

.typing-dot:nth-child(2) {
  animation-delay: 0.2s;
}

.typing-dot:nth-child(3) {
  animation-delay: 0.4s;
}

/* Scroll Indicator */
.scroll-indicator {
  position: absolute;
  bottom: var(--spacing-md);
  right: var(--spacing-md);
  opacity: 0;
  visibility: hidden;
  transition: all var(--transition-normal);
}

.scroll-indicator.show {
  opacity: 1;
  visibility: visible;
}

/* Input Container */
.input-container {
  background: var(--bg-primary);
  border-top: 1px solid var(--border-color);
  padding: var(--spacing-md);
}

.message-form {
  display: flex;
  align-items: flex-end;
  gap: var(--spacing-md);
  max-width: 100%;
}

.input-wrapper {
  flex: 1;
  position: relative;
  min-width: 0;
}

.input-wrapper textarea {
  width: 100%;
  min-height: 48px;
  max-height: 120px;
  padding: var(--spacing-md) var(--spacing-lg);
  padding-right: 60px;
  font-size: var(--font-size-md);
  font-family: inherit;
  line-height: 1.4;
  border: 2px solid var(--border-color);
  border-radius: 24px;
  background: var(--bg-primary);
  color: var(--text-primary);
  resize: none;
  outline: none;
  transition: all var(--transition-normal);
}

.input-wrapper textarea:focus {
  border-color: var(--border-focus);
  box-shadow: 0 0 0 3px rgba(24, 119, 242, 0.1);
}

.input-wrapper textarea::placeholder {
  color: var(--text-muted);
}

.char-counter {
  position: absolute;
  bottom: var(--spacing-sm);
  right: var(--spacing-md);
  font-size: var(--font-size-xs);
  color: var(--text-muted);
  pointer-events: none;
}

.char-counter.warning {
  color: var(--warning-color);
}

.char-counter.error {
  color: var(--error-color);
}

/* Loading Overlay */
.loading-overlay {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background: var(--bg-overlay);
  display: flex;
  align-items: center;
  justify-content: center;
  z-index: var(--z-modal);
  opacity: 0;
  visibility: hidden;
  transition: all var(--transition-normal);
}

.loading-overlay.show {
  opacity: 1;
  visibility: visible;
}

.loading-spinner {
  text-align: center;
}

.spinner {
  width: 40px;
  height: 40px;
  border: 4px solid rgba(255, 255, 255, 0.3);
  border-top: 4px solid var(--primary-color);
  border-radius: 50%;
  animation: spin 1s linear infinite;
}

/* Modal */
.modal {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background: var(--bg-overlay);
  display: flex;
  align-items: center;
  justify-content: center;
  z-index: var(--z-modal);
  opacity: 0;
  visibility: hidden;
  transition: all var(--transition-normal);
  padding: var(--spacing-lg);
}

.modal.show {
  opacity: 1;
  visibility: visible;
}

.modal-content {
  background: var(--bg-primary);
  border-radius: 12px;
  box-shadow: var(--shadow-lg);
  width: 100%;
  max-width: 400px;
  max-height: 80vh;
  overflow: hidden;
  transform: scale(0.9);
  transition: transform var(--transition-normal);
}

.modal.show .modal-content {
  transform: scale(1);
}

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

.modal-header h3 {
  margin: 0;
  font-size: var(--font-size-lg);
  color: var(--text-primary);
}

.modal-body {
  padding: var(--spacing-lg);
  display: flex;
  flex-direction: column;
  gap: var(--spacing-md);
}

/* Animations */
@keyframes fadeInUp {
  from {
    opacity: 0;
    transform: translateY(30px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

@keyframes messageSlideIn {
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

@keyframes typingPulse {
  0%, 60%, 100% {
    opacity: 0.4;
  }
  30% {
    opacity: 1;
  }
}

@keyframes shake {
  0%, 100% { transform: translateX(0); }
  25% { transform: translateX(-5px); }
  75% { transform: translateX(5px); }
}

@keyframes spin {
  0% { transform: rotate(0deg); }
  100% { transform: rotate(360deg); }
}

/* Responsive Design */
@media (max-width: 768px) {
  :root {
    --spacing-md: 0.75rem;
    --spacing-lg: 1rem;
    --spacing-xl: 1.25rem;
  }
  
  .theme-toggle {
    top: var(--spacing-sm);
    right: var(--spacing-sm);
    width: 44px;
    height: 44px;
  }
  
  .welcome-screen {
    padding: var(--spacing-md);
  }
  
  .business-logo-placeholder {
    width: 60px;
    height: 60px;
  }
  
  .business-logo-placeholder svg {
    width: 30px;
    height: 30px;
  }
  
  .welcome-title {
    font-size: var(--font-size-xl);
  }
  
  .welcome-subtitle {
    font-size: var(--font-size-md);
  }
  
  .chat-header {
    padding: var(--spacing-sm) var(--spacing-md);
  }
  
  .business-logo-small {
    width: 36px;
    height: 36px;
  }
  
  .business-logo-small svg {
    width: 18px;
    height: 18px;
  }
  
  .chat-title {
    font-size: var(--font-size-md);
  }
  
  .messages-list {
    padding: var(--spacing-sm);
  }
  
  .message-bubble {
    max-width: 85%;
    padding: var(--spacing-sm) var(--spacing-md);
  }
  
  .input-container {
    padding: var(--spacing-sm);
    padding-bottom: max(var(--spacing-sm), env(safe-area-inset-bottom));
  }
  
  .input-wrapper textarea {
    padding-right: 50px;
  }
  
  .btn-send {
    min-width: 44px;
    min-height: 44px;
  }
  
  .modal {
    padding: var(--spacing-md);
  }
}

@media (max-width: 480px) {
  .message-bubble {
    max-width: 90%;
  }
  
  .chat-title {
    font-size: var(--font-size-sm);
  }
  
  .business-info {
    gap: var(--spacing-sm);
  }
}

/* Touch-specific improvements */
@media (pointer: coarse) {
  .btn {
    min-height: 44px;
    min-width: 44px;
  }
  
  .input-wrapper textarea {
    font-size: 16px; /* Prevents zoom on iOS */
  }
}

/* Reduced motion preferences */
@media (prefers-reduced-motion: reduce) {
  * {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
  }
  
  .messages-list {
    scroll-behavior: auto;
  }
}