/* Modern Cloud.ai Style */
:root {
  /* Colors */
  --bg-primary: #0f0f0f;
  --bg-secondary: #1a1a1a;
  --bg-tertiary: #262626;
  --bg-surface: #2a2a2a;
  --border-primary: #404040;
  --border-secondary: #333333;
  --text-primary: #ffffff;
  --text-secondary: #b3b3b3;
  --text-tertiary: #808080;
  --accent-primary: #3b82f6;
  --accent-hover: #2563eb;
  --accent-light: rgba(59, 130, 246, 0.1);
  --success: #10b981;
  --warning: #f59e0b;
  --error: #ef4444;
  
  /* Spacing */
  --spacing-xs: 4px;
  --spacing-sm: 8px;
  --spacing-md: 12px;
  --spacing-lg: 16px;
  --spacing-xl: 20px;
  --spacing-2xl: 24px;
  
  /* Border radius */
  --radius-sm: 6px;
  --radius-md: 8px;
  --radius-lg: 12px;
  --radius-xl: 16px;
  --radius-full: 9999px;
  
  /* Shadows */
  --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
  --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1);
  --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1);
  --shadow-xl: 0 20px 25px -5px rgba(0, 0, 0, 0.1);
  
  /* Transitions */
  --transition-fast: 150ms ease;
  --transition-normal: 200ms ease;
  --transition-slow: 300ms ease;
}

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

html {
  font-size: 14px;
  line-height: 1.5;
}

body {
  font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
  background: var(--bg-primary);
  color: var(--text-primary);
  height: 100vh;
  overflow: hidden;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

/* App Container */
.app-container {
  display: flex;
  flex-direction: column;
  height: 100vh;
  position: relative;
}

/* Top Navigation */
.top-navbar {
  height: 56px;
  background: var(--bg-secondary);
  border-bottom: 1px solid var(--border-primary);
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0 var(--spacing-lg);
  position: relative;
  z-index: 50;
}

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

.sidebar-toggle {
  width: 36px;
  height: 36px;
  border-radius: var(--radius-md);
  border: none;
  background: transparent;
  color: var(--text-secondary);
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: all var(--transition-fast);
}

.sidebar-toggle:hover {
  background: var(--bg-tertiary);
  color: var(--text-primary);
}

.navbar-brand {
  display: flex;
  align-items: center;
  gap: var(--spacing-sm);
  text-decoration: none;
  color: var(--text-primary);
  font-weight: 600;
  font-size: 16px;
}

.brand-logo {
  width: 28px;
  height: 28px;
  background: var(--accent-primary);
  border-radius: var(--radius-md);
  display: flex;
  align-items: center;
  justify-content: center;
  color: white;
  font-weight: 800;
  font-size: 14px;
}

.navbar-center {
  position: absolute;
  left: 50%;
  transform: translateX(-50%);
}

.model-selector {
  display: flex;
  background: var(--bg-tertiary);
  border-radius: var(--radius-lg);
  padding: 2px;
  gap: 2px;
}

.model-tab {
  padding: var(--spacing-sm) var(--spacing-lg);
  border: none;
  background: transparent;
  color: var(--text-secondary);
  border-radius: var(--radius-md);
  cursor: pointer;
  font-size: 13px;
  font-weight: 500;
  transition: all var(--transition-fast);
  white-space: nowrap;
}

.model-tab.active {
  background: var(--accent-primary);
  color: white;
}

.model-tab:hover:not(.active) {
  background: var(--bg-surface);
  color: var(--text-primary);
}

.navbar-right {
  display: flex;
  align-items: center;
  gap: var(--spacing-sm);
}

.navbar-actions {
  display: flex;
  align-items: center;
  gap: var(--spacing-xs);
}

.nav-btn {
  width: 36px;
  height: 36px;
  border-radius: var(--radius-md);
  border: none;
  background: transparent;
  color: var(--text-secondary);
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: all var(--transition-fast);
}

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

.user-menu {
  position: relative;
}

.user-avatar {
  width: 32px;
  height: 32px;
  border-radius: var(--radius-full);
  cursor: pointer;
  border: 2px solid var(--border-primary);
  transition: border-color var(--transition-fast);
}

.user-avatar:hover {
  border-color: var(--accent-primary);
}

.user-dropdown {
  position: absolute;
  top: 100%;
  right: 0;
  margin-top: var(--spacing-sm);
  background: var(--bg-secondary);
  border: 1px solid var(--border-primary);
  border-radius: var(--radius-lg);
  min-width: 240px;
  box-shadow: var(--shadow-lg);
  opacity: 0;
  visibility: hidden;
  transform: translateY(-8px);
  transition: all var(--transition-fast);
  z-index: 100;
}

.user-dropdown.show {
  opacity: 1;
  visibility: visible;
  transform: translateY(0);
}

.dropdown-header {
  padding: var(--spacing-lg);
  border-bottom: 1px solid var(--border-primary);
}

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

.dropdown-avatar {
  width: 40px;
  height: 40px;
  border-radius: var(--radius-full);
}

.dropdown-user-details h4 {
  font-size: 14px;
  font-weight: 600;
  color: var(--text-primary);
  margin-bottom: 2px;
}

.dropdown-user-details p {
  font-size: 12px;
  color: var(--text-secondary);
}

.dropdown-item {
  display: flex;
  align-items: center;
  gap: var(--spacing-md);
  padding: var(--spacing-md) var(--spacing-lg);
  color: var(--text-secondary);
  text-decoration: none;
  cursor: pointer;
  transition: all var(--transition-fast);
  font-size: 14px;
}

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

.dropdown-divider {
  height: 1px;
  background: var(--border-primary);
  margin: var(--spacing-xs) 0;
}

/* Sidebar */
.sidebar-overlay {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background: rgba(0, 0, 0, 0.5);
  z-index: 40;
  opacity: 0;
  visibility: hidden;
  transition: all var(--transition-slow);
}

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

.sidebar {
  width: 280px;
  background: var(--bg-secondary);
  border-right: 1px solid var(--border-primary);
  display: flex;
  flex-direction: column;
  position: fixed;
  top: 56px;
  left: 0;
  bottom: 0;
  z-index: 50;
  transform: translateX(-100%);
  transition: transform var(--transition-slow);
}

.sidebar.open {
  transform: translateX(0);
}

.sidebar-header {
  padding: var(--spacing-xl) var(--spacing-lg);
  border-bottom: 1px solid var(--border-primary);
}

.new-chat-btn {
  width: 100%;
  padding: var(--spacing-md) var(--spacing-lg);
  background: var(--accent-primary);
  border: none;
  border-radius: var(--radius-lg);
  color: white;
  font-weight: 500;
  cursor: pointer;
  transition: all var(--transition-fast);
  display: flex;
  align-items: center;
  justify-content: center;
  gap: var(--spacing-sm);
  font-size: 14px;
}

.new-chat-btn:hover {
  background: var(--accent-hover);
}

.chat-sessions {
  flex: 1;
  overflow-y: auto;
  padding: var(--spacing-sm) var(--spacing-md);
}

.session-group {
  margin-bottom: var(--spacing-xl);
}

.session-group-title {
  font-size: 12px;
  font-weight: 600;
  color: var(--text-tertiary);
  text-transform: uppercase;
  letter-spacing: 0.5px;
  margin-bottom: var(--spacing-sm);
  padding: 0 var(--spacing-sm);
}

.chat-session {
  padding: var(--spacing-md);
  margin-bottom: 2px;
  border-radius: var(--radius-md);
  cursor: pointer;
  transition: all var(--transition-fast);
  position: relative;
}

.chat-session:hover {
  background: var(--bg-tertiary);
}

.chat-session.active {
  background: var(--accent-light);
  border-left: 3px solid var(--accent-primary);
}

.session-title {
  font-size: 14px;
  font-weight: 500;
  margin-bottom: 2px;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
  color: var(--text-primary);
}

.session-preview {
  font-size: 12px;
  color: var(--text-secondary);
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
  margin-bottom: 2px;
}

.session-date {
  font-size: 11px;
  color: var(--text-tertiary);
}

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

/* Chat Container */
.chat-container {
  flex: 1;
  display: flex;
  flex-direction: column;
  max-width: 768px;
  margin: 0 auto;
  width: 100%;
  padding: 0 var(--spacing-xl);
}

.chat-messages {
  flex: 1;
  overflow-y: auto;
  padding: var(--spacing-2xl) 0;
  display: flex;
  flex-direction: column;
  gap: var(--spacing-xl);
  scroll-behavior: smooth;
}

.message {
  display: flex;
  gap: var(--spacing-md);
  max-width: 100%;
  animation: messageSlide 0.3s ease-out;
}

@keyframes messageSlide {
  from {
    opacity: 0;
    transform: translateY(10px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

.message.user {
  align-self: flex-end;
  flex-direction: row-reverse;
  max-width: 80%;
}

.message.ai {
  max-width: 100%;
}

.message-avatar {
  width: 28px;
  height: 28px;
  border-radius: var(--radius-full);
  background: var(--accent-primary);
  display: flex;
  align-items: center;
  justify-content: center;
  color: white;
  font-weight: 600;
  font-size: 12px;
  flex-shrink: 0;
  margin-top: 2px;
}

.message.ai .message-avatar {
  background: var(--bg-surface);
  color: var(--text-primary);
  border: 1px solid var(--border-primary);
}

.message-content {
  background: var(--bg-surface);
  padding: var(--spacing-md) var(--spacing-lg);
  border-radius: var(--radius-xl);
  line-height: 1.6;
  word-wrap: break-word;
  border: 1px solid var(--border-secondary);
  font-size: 14px;
}

.message.user .message-content {
  background: var(--accent-primary);
  color: white;
  border: none;
}

.message.ai .message-content {
  background: var(--bg-secondary);
  border: 1px solid var(--border-primary);
}

/* Welcome Screen */
.welcome-screen {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  flex: 1;
  text-align: center;
  padding: 40px var(--spacing-xl);
}

.welcome-logo {
  width: 64px;
  height: 64px;
  margin-bottom: var(--spacing-2xl);
  opacity: 0.8;
}

.welcome-title {
  font-size: 32px;
  font-weight: 700;
  margin-bottom: var(--spacing-md);
  color: var(--text-primary);
  background: linear-gradient(135deg, var(--accent-primary), var(--success));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.welcome-subtitle {
  font-size: 16px;
  color: var(--text-secondary);
  margin-bottom: 32px;
  max-width: 500px;
  line-height: 1.5;
}

.welcome-suggestions {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
  gap: var(--spacing-md);
  max-width: 600px;
  width: 100%;
}

.suggestion-card {
  background: var(--bg-secondary);
  border: 1px solid var(--border-primary);
  border-radius: var(--radius-lg);
  padding: var(--spacing-lg);
  cursor: pointer;
  transition: all var(--transition-fast);
  text-align: left;
}

.suggestion-card:hover {
  border-color: var(--accent-primary);
  transform: translateY(-1px);
  box-shadow: var(--shadow-md);
  background: var(--bg-tertiary);
}

.suggestion-title {
  font-weight: 600;
  margin-bottom: 6px;
  color: var(--text-primary);
  font-size: 14px;
}

.suggestion-desc {
  font-size: 13px;
  color: var(--text-secondary);
  line-height: 1.4;
}

/* Chat Input */
.chat-input-container {
  padding: var(--spacing-xl) 0 var(--spacing-2xl) 0;
}

.chat-input {
  display: flex;
  align-items: flex-end;
  gap: var(--spacing-sm);
  background: var(--bg-secondary);
  border: 1px solid var(--border-primary);
  border-radius: var(--radius-xl);
  padding: 6px;
  transition: all var(--transition-fast);
  position: relative;
}

.chat-input:focus-within {
  border-color: var(--accent-primary);
  box-shadow: 0 0 0 3px var(--accent-light);
}

#messageInput {
  flex: 1;
  background: transparent;
  border: none;
  outline: none;
  padding: 10px var(--spacing-md);
  color: var(--text-primary);
  font-size: 14px;
  resize: none;
  min-height: 20px;
  max-height: 120px;
  font-family: inherit;
  line-height: 1.5;
}

#messageInput::placeholder {
  color: var(--text-tertiary);
}

.input-btn {
  width: 36px;
  height: 36px;
  border-radius: var(--radius-md);
  border: none;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: all var(--transition-fast);
  flex-shrink: 0;
}

.voice-btn, .file-btn {
  background: transparent;
  color: var(--text-secondary);
}

.voice-btn:hover, .file-btn:hover {
  background: var(--bg-tertiary);
  color: var(--text-primary);
}

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

.send-btn:hover {
  background: var(--accent-hover);
}

.send-btn:disabled {
  background: var(--bg-tertiary);
  color: var(--text-tertiary);
  cursor: not-allowed;
}

/* Responsive */
@media (max-width: 768px) {
  .sidebar {
    width: 100%;
  }
  
  .navbar-center {
    display: none;
  }
  
  .navbar-actions {
    gap: 2px;
  }
  
  .chat-container {
    padding: 0 var(--spacing-lg);
  }
  
  .chat-messages {
    padding: var(--spacing-lg) 0;
  }
  
  .message {
    gap: var(--spacing-sm);
  }
  
  .message.user {
    max-width: 90%;
  }
  
  .welcome-suggestions {
    grid-template-columns: 1fr;
    gap: var(--spacing-sm);
  }
  
  .welcome-title {
    font-size: 24px;
  }
  
  .welcome-subtitle {
    font-size: 14px;
  }
}

/* Scrollbar */
::-webkit-scrollbar {
  width: 6px;
}

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

::-webkit-scrollbar-thumb {
  background: var(--border-primary);
  border-radius: 3px;
}

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

/* Selection */
::selection {
  background: var(--accent-light);
  color: var(--text-primary);
}

/* Focus */
*:focus {
  outline: none;
}

*:focus-visible {
  outline: 2px solid var(--accent-primary);
  outline-offset: 2px;
}