/* Nexus Design System */
:root {
  /* Colors */
  --bg-primary: #0a0a0b;
  --bg-secondary: #131316;
  --bg-tertiary: #1a1a1f;
  --bg-elevated: #232329;

  --text-primary: #fafafa;
  --text-secondary: #a1a1aa;
  --text-tertiary: #71717a;

  --accent: #6366f1;
  --accent-hover: #818cf8;
  --accent-muted: rgba(99, 102, 241, 0.1);

  --success: #22c55e;
  --warning: #f59e0b;
  --danger: #ef4444;

  --border: rgba(255, 255, 255, 0.06);
  --border-hover: rgba(255, 255, 255, 0.1);

  /* Typography */
  --font-sans: 'Inter', -apple-system, BlinkMacSystemFont, sans-serif;
  --font-mono: 'JetBrains Mono', 'Fira Code', monospace;

  /* Spacing */
  --space-1: 0.25rem;
  --space-2: 0.5rem;
  --space-3: 0.75rem;
  --space-4: 1rem;
  --space-5: 1.25rem;
  --space-6: 1.5rem;
  --space-8: 2rem;
  --space-10: 2.5rem;
  --space-12: 3rem;

  /* Transitions */
  --transition-fast: 150ms cubic-bezier(0.4, 0, 0.2, 1);
  --transition-base: 250ms cubic-bezier(0.4, 0, 0.2, 1);
  --transition-slow: 350ms cubic-bezier(0.4, 0, 0.2, 1);

  /* Shadows */
  --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.3);
  --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.4);
  --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.5);

  /* Blur */
  --blur-sm: blur(8px);
  --blur-md: blur(16px);
  --blur-lg: blur(24px);
}

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

html {
  font-size: 16px;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

body {
  font-family: var(--font-sans);
  background: var(--bg-primary);
  color: var(--text-primary);
  line-height: 1.5;
  overflow: hidden;
  height: 100vh;
}

/* Screen Management */
.screen {
  display: none;
  height: 100vh;
  width: 100vw;
}

.screen.active {
  display: flex;
}

/* Auth Screen */
.auth-bg {
  position: fixed;
  inset: 0;
  overflow: hidden;
  z-index: 0;
}

.gradient-orb {
  position: absolute;
  border-radius: 50%;
  filter: blur(100px);
  opacity: 0.4;
  animation: float 20s ease-in-out infinite;
}

.orb-1 {
  width: 600px;
  height: 600px;
  background: radial-gradient(circle, var(--accent), transparent 70%);
  top: -200px;
  right: -200px;
  animation-delay: 0s;
}

.orb-2 {
  width: 500px;
  height: 500px;
  background: radial-gradient(circle, #8b5cf6, transparent 70%);
  bottom: -150px;
  left: -150px;
  animation-delay: -10s;
}

@keyframes float {
  0%, 100% { transform: translate(0, 0) scale(1); }
  33% { transform: translate(30px, -30px) scale(1.05); }
  66% { transform: translate(-20px, 20px) scale(0.95); }
}

.auth-container {
  position: relative;
  z-index: 1;
  margin: auto;
  text-align: center;
  padding: var(--space-8);
  max-width: 420px;
  width: 100%;
}

.brand {
  margin-bottom: var(--space-10);
}

.logo {
  width: 64px;
  height: 64px;
  margin: 0 auto var(--space-5);
  color: var(--text-primary);
}

.logo svg {
  width: 100%;
  height: 100%;
}

.brand h1 {
  font-size: 2rem;
  font-weight: 600;
  letter-spacing: 0.2em;
  margin-bottom: var(--space-2);
}

.tagline {
  color: var(--text-secondary);
  font-size: 0.9375rem;
  font-weight: 400;
}

.auth-card {
  background: var(--bg-secondary);
  border: 1px solid var(--border);
  border-radius: 20px;
  padding: var(--space-8);
  backdrop-filter: var(--blur-sm);
  box-shadow: var(--shadow-lg);
}

.input-group {
  margin-bottom: var(--space-6);
  text-align: left;
}

.input-group label {
  display: block;
  font-size: 0.8125rem;
  font-weight: 500;
  color: var(--text-secondary);
  margin-bottom: var(--space-2);
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

.input-group input,
.input-group textarea {
  width: 100%;
  padding: var(--space-3) var(--space-4);
  background: var(--bg-tertiary);
  border: 1px solid var(--border);
  border-radius: 12px;
  color: var(--text-primary);
  font-family: var(--font-sans);
  font-size: 0.9375rem;
  transition: all var(--transition-fast);
  outline: none;
  resize: none;
}

.input-group input:focus,
.input-group textarea:focus {
  border-color: var(--accent);
  background: var(--bg-elevated);
}

.input-group input::placeholder,
.input-group textarea::placeholder {
  color: var(--text-tertiary);
}

.identity-preview {
  text-align: left;
  margin-bottom: var(--space-6);
}

.id-box {
  display: flex;
  align-items: center;
  gap: var(--space-2);
  padding: var(--space-3) var(--space-4);
  background: var(--bg-tertiary);
  border: 1px solid var(--border);
  border-radius: 12px;
}

.id-box code {
  flex: 1;
  font-family: var(--font-mono);
  font-size: 0.8125rem;
  color: var(--text-secondary);
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}

.btn-primary {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-2);
  width: 100%;
  padding: var(--space-4) var(--space-6);
  background: var(--accent);
  color: white;
  border: none;
  border-radius: 12px;
  font-family: var(--font-sans);
  font-size: 0.9375rem;
  font-weight: 500;
  cursor: pointer;
  transition: all var(--transition-fast);
}

.btn-primary:hover {
  background: var(--accent-hover);
  transform: translateY(-1px);
  box-shadow: 0 8px 20px -4px rgba(99, 102, 241, 0.4);
}

.btn-secondary {
  display: inline-flex;
  align-items: center;
  gap: var(--space-2);
  padding: var(--space-2) var(--space-4);
  background: var(--bg-elevated);
  border: 1px solid var(--border);
  border-radius: 8px;
  color: var(--text-secondary);
  font-family: var(--font-sans);
  font-size: 0.8125rem;
  font-weight: 500;
  cursor: pointer;
  transition: all var(--transition-fast);
}

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

.icon-btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 36px;
  height: 36px;
  background: transparent;
  border: 1px solid var(--border);
  border-radius: 10px;
  color: var(--text-secondary);
  cursor: pointer;
  transition: all var(--transition-fast);
  flex-shrink: 0;
}

.icon-btn:hover {
  background: var(--bg-elevated);
  color: var(--text-primary);
  border-color: var(--border-hover);
}

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

.icon-btn.send:hover {
  background: var(--accent-hover);
  transform: scale(1.05);
}

.auth-footer {
  margin-top: var(--space-8);
  color: var(--text-tertiary);
  font-size: 0.8125rem;
}

/* Main App Layout */
#app-screen {
  display: none;
}

#app-screen.active {
  display: flex;
}

.sidebar {
  width: 320px;
  background: var(--bg-secondary);
  border-right: 1px solid var(--border);
  display: flex;
  flex-direction: column;
  flex-shrink: 0;
}

.sidebar-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: var(--space-4) var(--space-5);
  border-bottom: 1px solid var(--border);
}

.brand-small {
  display: flex;
  align-items: center;
  gap: var(--space-3);
  color: var(--text-primary);
}

.brand-small svg {
  width: 28px;
  height: 28px;
}

.brand-small span {
  font-size: 0.9375rem;
  font-weight: 600;
  letter-spacing: 0.1em;
}

.tabs {
  display: flex;
  padding: var(--space-2);
  gap: var(--space-1);
  border-bottom: 1px solid var(--border);
}

.tab {
  flex: 1;
  padding: var(--space-2) var(--space-4);
  background: transparent;
  border: none;
  border-radius: 8px;
  color: var(--text-tertiary);
  font-family: var(--font-sans);
  font-size: 0.8125rem;
  font-weight: 500;
  cursor: pointer;
  transition: all var(--transition-fast);
}

.tab:hover {
  color: var(--text-secondary);
  background: var(--bg-tertiary);
}

.tab.active {
  color: var(--text-primary);
  background: var(--bg-elevated);
}

.conversation-list {
  flex: 1;
  overflow-y: auto;
  padding: var(--space-2);
}

.conversation-item {
  display: flex;
  align-items: center;
  gap: var(--space-3);
  padding: var(--space-3);
  border-radius: 12px;
  cursor: pointer;
  transition: all var(--transition-fast);
  margin-bottom: var(--space-1);
}

.conversation-item:hover {
  background: var(--bg-tertiary);
}

.conversation-item.active {
  background: var(--accent-muted);
}

.conversation-item.active .conversation-name {
  color: var(--accent-hover);
}

.conversation-avatar {
  width: 44px;
  height: 44px;
  border-radius: 50%;
  background: linear-gradient(135deg, var(--accent), #8b5cf6);
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 600;
  font-size: 1rem;
  color: white;
  flex-shrink: 0;
}

.conversation-avatar.group {
  background: linear-gradient(135deg, var(--success), #10b981);
}

.conversation-info {
  flex: 1;
  min-width: 0;
}

.conversation-name {
  font-weight: 500;
  font-size: 0.9375rem;
  color: var(--text-primary);
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
  margin-bottom: 2px;
}

.conversation-preview {
  font-size: 0.8125rem;
  color: var(--text-tertiary);
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

.conversation-meta {
  text-align: right;
  flex-shrink: 0;
}

.conversation-time {
  font-size: 0.6875rem;
  color: var(--text-tertiary);
  margin-bottom: 4px;
}

.unread-badge {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-width: 18px;
  height: 18px;
  padding: 0 6px;
  background: var(--accent);
  color: white;
  border-radius: 9px;
  font-size: 0.6875rem;
  font-weight: 600;
}

.sidebar-footer {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: var(--space-4) var(--space-5);
  border-top: 1px solid var(--border);
  background: var(--bg-tertiary);
}

.user-info {
  display: flex;
  align-items: center;
  gap: var(--space-3);
}

.avatar {
  width: 36px;
  height: 36px;
  border-radius: 50%;
  background: linear-gradient(135deg, var(--accent), #8b5cf6);
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 600;
  font-size: 0.875rem;
  color: white;
}

.user-details {
  display: flex;
  flex-direction: column;
}

.user-details .name {
  font-size: 0.875rem;
  font-weight: 500;
  color: var(--text-primary);
}

.user-details .status {
  font-size: 0.75rem;
  color: var(--success);
  display: flex;
  align-items: center;
  gap: 4px;
}

.user-details .status::before {
  content: '';
  width: 6px;
  height: 6px;
  background: var(--success);
  border-radius: 50%;
}

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

/* Empty State */
.empty-state {
  display: none;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  height: 100%;
  text-align: center;
  padding: var(--space-10);
}

.empty-state.active {
  display: flex;
}

.empty-icon {
  width: 120px;
  height: 120px;
  color: var(--text-tertiary);
  opacity: 0.5;
  margin-bottom: var(--space-6);
}

.empty-icon svg {
  width: 100%;
  height: 100%;
}

.empty-state h2 {
  font-size: 1.5rem;
  font-weight: 600;
  color: var(--text-primary);
  margin-bottom: var(--space-2);
}

.empty-state p {
  color: var(--text-secondary);
  font-size: 0.9375rem;
  max-width: 360px;
}

/* Chat View */
.chat-view {
  display: none;
  flex-direction: column;
  height: 100%;
}

.chat-view.active {
  display: flex;
}

.chat-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: var(--space-4) var(--space-6);
  border-bottom: 1px solid var(--border);
  background: var(--bg-secondary);
}

.chat-info {
  display: flex;
  align-items: center;
  gap: var(--space-4);
}

.avatar-group {
  display: flex;
}

.avatar-group .avatar {
  margin-left: -8px;
  border: 2px solid var(--bg-secondary);
}

.avatar-group .avatar:first-child {
  margin-left: 0;
}

.chat-meta h3 {
  font-size: 1rem;
  font-weight: 600;
  color: var(--text-primary);
  margin-bottom: 2px;
}

.chat-meta .subtitle {
  font-size: 0.8125rem;
  color: var(--text-tertiary);
}

.chat-actions {
  display: flex;
  gap: var(--space-2);
}

/* Messages */
.messages {
  flex: 1;
  overflow-y: auto;
  padding: var(--space-6);
  display: flex;
  flex-direction: column;
  gap: var(--space-4);
}

.message {
  display: flex;
  flex-direction: column;
  max-width: 70%;
  animation: messageIn 0.3s ease;
}

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

.message.sent {
  align-self: flex-end;
  align-items: flex-end;
}

.message.received {
  align-self: flex-start;
  align-items: flex-start;
}

.message-bubble {
  padding: var(--space-3) var(--space-4);
  border-radius: 16px;
  font-size: 0.9375rem;
  line-height: 1.5;
  word-break: break-word;
}

.message.sent .message-bubble {
  background: var(--accent);
  color: white;
  border-bottom-right-radius: 4px;
}

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

.message-time {
  font-size: 0.6875rem;
  color: var(--text-tertiary);
  margin-top: var(--space-1);
}

.message.sent .message-time {
  color: var(--text-tertiary);
}

.message-file {
  display: flex;
  align-items: center;
  gap: var(--space-3);
  padding: var(--space-4);
  background: rgba(0, 0, 0, 0.2);
  border-radius: 12px;
  margin-bottom: var(--space-2);
}

.message-file-icon {
  width: 40px;
  height: 40px;
  background: var(--bg-elevated);
  border-radius: 10px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.25rem;
}

.message-file-info {
  flex: 1;
  min-width: 0;
}

.message-file-name {
  font-weight: 500;
  font-size: 0.875rem;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

.message-file-size {
  font-size: 0.75rem;
  opacity: 0.7;
}

.message-file-download {
  padding: var(--space-2) var(--space-3);
  background: var(--bg-elevated);
  border: none;
  border-radius: 8px;
  color: var(--text-primary);
  font-size: 0.8125rem;
  font-weight: 500;
  cursor: pointer;
  transition: all var(--transition-fast);
}

.message-file-download:hover {
  background: var(--text-primary);
  color: var(--bg-primary);
}

.system-message {
  align-self: center;
  padding: var(--space-2) var(--space-4);
  background: var(--bg-tertiary);
  border-radius: 20px;
  font-size: 0.8125rem;
  color: var(--text-tertiary);
  margin: var(--space-2) 0;
}

/* Input Area */
.input-area {
  padding: var(--space-4) var(--space-6);
  border-top: 1px solid var(--border);
  background: var(--bg-secondary);
}

.input-container {
  display: flex;
  align-items: flex-end;
  gap: var(--space-3);
  padding: var(--space-2);
  background: var(--bg-tertiary);
  border: 1px solid var(--border);
  border-radius: 16px;
  transition: all var(--transition-fast);
}

.input-container:focus-within {
  border-color: var(--accent);
  background: var(--bg-elevated);
}

#message-input {
  flex: 1;
  background: transparent;
  border: none;
  color: var(--text-primary);
  font-family: var(--font-sans);
  font-size: 0.9375rem;
  line-height: 1.5;
  padding: var(--space-2);
  outline: none;
  resize: none;
  max-height: 120px;
  min-height: 24px;
}

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

/* Modal */
.modal {
  display: none;
  position: fixed;
  inset: 0;
  z-index: 1000;
  align-items: center;
  justify-content: center;
}

.modal.active {
  display: flex;
}

.modal-backdrop {
  position: absolute;
  inset: 0;
  background: rgba(0, 0, 0, 0.6);
  backdrop-filter: var(--blur-sm);
}

.modal-content {
  position: relative;
  width: 90%;
  max-width: 440px;
  background: var(--bg-secondary);
  border: 1px solid var(--border);
  border-radius: 20px;
  box-shadow: var(--shadow-lg);
  animation: modalIn 0.3s ease;
}

@keyframes modalIn {
  from {
    opacity: 0;
    transform: scale(0.95) translateY(10px);
  }
  to {
    opacity: 1;
    transform: scale(1) translateY(0);
  }
}

.modal-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: var(--space-5) var(--space-6) 0;
}

.modal-header h3 {
  font-size: 1.125rem;
  font-weight: 600;
}

.modal-close {
  background: transparent;
  border: none;
  color: var(--text-tertiary);
  cursor: pointer;
  padding: var(--space-1);
}

.modal-close:hover {
  color: var(--text-primary);
}

.modal-tabs {
  display: flex;
  gap: var(--space-1);
  padding: var(--space-4) var(--space-6) 0;
}

.modal-tab {
  padding: var(--space-2) var(--space-4);
  background: transparent;
  border: none;
  border-radius: 8px;
  color: var(--text-tertiary);
  font-family: var(--font-sans);
  font-size: 0.875rem;
  font-weight: 500;
  cursor: pointer;
  transition: all var(--transition-fast);
}

.modal-tab:hover {
  color: var(--text-secondary);
}

.modal-tab.active {
  background: var(--bg-elevated);
  color: var(--text-primary);
}

.modal-body {
  padding: var(--space-5) var(--space-6);
}

.form-section {
  display: none;
}

.form-section.active {
  display: block;
}

.settings-section {
  margin-bottom: var(--space-6);
}

.settings-section h4 {
  font-size: 0.75rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: var(--text-tertiary);
  margin-bottom: var(--space-3);
}

.setting-item {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: var(--space-3) 0;
  border-bottom: 1px solid var(--border);
}

.setting-item span {
  font-size: 0.9375rem;
  color: var(--text-primary);
}

.settings-id {
  font-family: var(--font-mono);
  font-size: 0.8125rem;
  color: var(--text-secondary);
  max-width: 180px;
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}

.btn-danger {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-2);
  width: 100%;
  padding: var(--space-3) var(--space-4);
  background: rgba(239, 68, 68, 0.1);
  border: 1px solid var(--danger);
  border-radius: 10px;
  color: var(--danger);
  font-family: var(--font-sans);
  font-size: 0.9375rem;
  font-weight: 500;
  cursor: pointer;
  transition: all var(--transition-fast);
}

.btn-danger:hover {
  background: var(--danger);
  color: white;
}

.btn-text {
  background: transparent;
  border: none;
  color: var(--accent);
  font-size: 0.875rem;
  font-weight: 500;
  cursor: pointer;
  padding: var(--space-2) var(--space-3);
  border-radius: 8px;
  transition: all var(--transition-fast);
}

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

/* Connection History */
.history-list {
  max-height: 400px;
  overflow-y: auto;
}

.empty-history {
  text-align: center;
  color: var(--text-tertiary);
  padding: var(--space-8) 0;
}

.history-item {
  display: flex;
  align-items: center;
  gap: var(--space-3);
  padding: var(--space-3);
  border-radius: 12px;
  cursor: pointer;
  transition: all var(--transition-fast);
  margin-bottom: var(--space-2);
}

.history-item:hover {
  background: var(--bg-tertiary);
}

.history-avatar {
  width: 40px;
  height: 40px;
  border-radius: 50%;
  background: var(--bg-elevated);
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 600;
  font-size: 0.875rem;
  color: var(--text-primary);
}

.history-info {
  flex: 1;
  min-width: 0;
}

.history-name {
  font-weight: 500;
  font-size: 0.9375rem;
  color: var(--text-primary);
  margin-bottom: 2px;
}

.history-id {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  color: var(--text-tertiary);
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}

.history-time {
  font-size: 0.75rem;
  color: var(--text-tertiary);
}

.history-actions {
  display: flex;
  gap: var(--space-2);
}

.history-btn {
  padding: var(--space-2) var(--space-3);
  background: var(--bg-elevated);
  border: none;
  border-radius: 8px;
  color: var(--text-secondary);
  font-size: 0.75rem;
  font-weight: 500;
  cursor: pointer;
  transition: all var(--transition-fast);
}

.history-btn:hover {
  background: var(--accent);
  color: white;
}

.history-btn.delete:hover {
  background: var(--danger);
}

.divider {
  display: flex;
  align-items: center;
  gap: var(--space-3);
  margin: var(--space-6) 0;
  color: var(--text-tertiary);
  font-size: 0.8125rem;
}

.divider::before,
.divider::after {
  content: '';
  flex: 1;
  height: 1px;
  background: var(--border);
}

.share-section {
  display: flex;
  align-items: center;
  gap: var(--space-3);
  padding: var(--space-3) var(--space-4);
  background: var(--bg-tertiary);
  border: 1px solid var(--border);
  border-radius: 12px;
}

.share-section code {
  flex: 1;
  font-family: var(--font-mono);
  font-size: 0.8125rem;
  color: var(--text-secondary);
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}

/* Call Overlay */
.call-overlay {
  display: none;
  position: fixed;
  inset: 0;
  z-index: 2000;
  background: var(--bg-primary);
  flex-direction: column;
}

.call-overlay.active {
  display: flex;
}

.call-grid {
  flex: 1;
  display: grid;
  gap: var(--space-4);
  padding: var(--space-6);
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
  overflow-y: auto;
}

.video-container {
  position: relative;
  background: var(--bg-secondary);
  border-radius: 16px;
  overflow: hidden;
  aspect-ratio: 16/9;
}

.video-container video {
  width: 100%;
  height: 100%;
  object-fit: cover;
}

.video-container.local {
  border: 2px solid var(--accent);
}

.video-label {
  position: absolute;
  bottom: var(--space-3);
  left: var(--space-3);
  padding: var(--space-1) var(--space-3);
  background: rgba(0, 0, 0, 0.6);
  backdrop-filter: var(--blur-sm);
  border-radius: 20px;
  font-size: 0.8125rem;
  font-weight: 500;
}

.call-controls {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-4);
  padding: var(--space-6);
  background: linear-gradient(to top, var(--bg-primary), transparent);
}

.call-btn {
  width: 56px;
  height: 56px;
  border-radius: 50%;
  background: var(--bg-elevated);
  border: 1px solid var(--border);
  color: var(--text-primary);
  display: flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  transition: all var(--transition-fast);
}

.call-btn:hover {
  background: var(--bg-tertiary);
  transform: scale(1.05);
}

.call-btn.active {
  background: var(--accent);
  border-color: var(--accent);
}

.call-btn.hangup {
  background: var(--danger);
  border-color: var(--danger);
  color: white;
}

.call-btn.hangup:hover {
  background: #dc2626;
}

/* Incoming Call Modal */
.call-modal {
  text-align: center;
  max-width: 360px;
}

.call-info {
  padding: var(--space-8) var(--space-6);
}

.call-avatar {
  width: 80px;
  height: 80px;
  margin: 0 auto var(--space-5);
  background: var(--bg-tertiary);
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--text-primary);
  animation: pulse 2s infinite;
}

@keyframes pulse {
  0%, 100% { transform: scale(1); opacity: 1; }
  50% { transform: scale(1.05); opacity: 0.8; }
}

.call-info h3 {
  font-size: 1.5rem;
  font-weight: 600;
  margin-bottom: var(--space-2);
}

.call-info p {
  color: var(--text-secondary);
  font-size: 1rem;
}

.call-actions-row {
  display: flex;
  justify-content: center;
  gap: var(--space-6);
  padding: 0 var(--space-6) var(--space-8);
}

.call-action-btn {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: var(--space-2);
  background: transparent;
  border: none;
  cursor: pointer;
  transition: all var(--transition-fast);
}

.call-action-btn svg {
  width: 56px;
  height: 56px;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 16px;
  transition: all var(--transition-fast);
}

.call-action-btn span {
  font-size: 0.875rem;
  color: var(--text-secondary);
}

.call-action-btn.reject svg {
  background: var(--danger);
  color: white;
}

.call-action-btn.reject:hover svg {
  background: #dc2626;
  transform: scale(1.1);
}

.call-action-btn.accept svg {
  background: var(--success);
  color: white;
}

.call-action-btn.accept:hover svg {
  background: #16a34a;
  transform: scale(1.1);
}

/* Toast Notifications */
.toast-container {
  position: fixed;
  top: var(--space-6);
  right: var(--space-6);
  z-index: 3000;
  display: flex;
  flex-direction: column;
  gap: var(--space-3);
}

.toast {
  display: flex;
  align-items: center;
  gap: var(--space-3);
  padding: var(--space-4) var(--space-5);
  background: var(--bg-secondary);
  border: 1px solid var(--border);
  border-radius: 12px;
  box-shadow: var(--shadow-lg);
  animation: toastIn 0.3s ease;
  max-width: 400px;
}

.toast.hide {
  animation: toastOut 0.3s ease forwards;
}

@keyframes toastIn {
  from {
    opacity: 0;
    transform: translateX(20px);
  }
  to {
    opacity: 1;
    transform: translateX(0);
  }
}

@keyframes toastOut {
  to {
    opacity: 0;
    transform: translateX(20px);
  }
}

.toast-icon {
  width: 20px;
  height: 20px;
  flex-shrink: 0;
}

.toast-content {
  flex: 1;
}

.toast-title {
  font-weight: 500;
  font-size: 0.9375rem;
  margin-bottom: 2px;
}

.toast-message {
  font-size: 0.8125rem;
  color: var(--text-secondary);
}

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

::-webkit-scrollbar-track {
  background: transparent;
}

::-webkit-scrollbar-thumb {
  background: var(--text-tertiary);
  border-radius: 3px;
  opacity: 0.3;
}

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

/* Selection */
::selection {
  background: var(--accent);
  color: white;
}

/* Language Switcher */
.language-switcher {
  position: absolute;
  top: var(--space-5);
  right: var(--space-5);
  z-index: 10;
}

.lang-btn {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 40px;
  height: 40px;
  background: var(--bg-tertiary);
  border: 1px solid var(--border);
  border-radius: 10px;
  color: var(--text-secondary);
  font-size: 0.875rem;
  font-weight: 500;
  cursor: pointer;
  transition: all var(--transition-fast);
}

.lang-btn:hover {
  background: var(--bg-elevated);
  border-color: var(--accent);
  color: var(--text-primary);
}

#current-lang {
  font-family: 'Noto Sans SC', sans-serif;
}

.header-actions {
  display: flex;
  align-items: center;
  gap: var(--space-2);
}

#lang-indicator {
  font-size: 0.75rem;
  font-weight: 500;
  font-family: 'Noto Sans SC', sans-serif;
}

/* Chinese font support */
body:lang(zh) {
  --font-sans: 'Noto Sans SC', 'Inter', -apple-system, BlinkMacSystemFont, sans-serif;
}

body:lang(zh) .brand h1 {
  letter-spacing: 0.3em;
}

body:lang(zh) .tagline {
  letter-spacing: 0.05em;
}

/* Responsive */
@media (max-width: 768px) {
  .sidebar {
    position: fixed;
    left: 0;
    top: 0;
    bottom: 0;
    z-index: 100;
    transform: translateX(-100%);
    transition: transform var(--transition-base);
  }

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

  .message {
    max-width: 85%;
  }

  .call-grid {
    grid-template-columns: 1fr;
  }
}