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

body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Microsoft YaHei", sans-serif;
  height: 100vh;
  overflow: hidden;
  color: #333;
}

button,
input {
  font: inherit;
}

button {
  transition: opacity 0.15s ease, background 0.15s ease, transform 0.15s ease;
}

button:active {
  transform: translateY(1px);
}

/* Screen switching */
.screen {
  display: none;
  height: 100vh;
}

.screen.active {
  display: flex;
}

/* Login screen */
#screen-login {
  justify-content: center;
  align-items: center;
  padding: 20px;
  background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
}

.login-container {
  background: white;
  border-radius: 16px;
  padding: 40px;
  box-shadow: 0 20px 60px rgba(0, 0, 0, 0.3);
  width: 360px;
  max-width: 100%;
}

.login-container h1 {
  text-align: center;
  margin-bottom: 30px;
  color: #333;
  letter-spacing: 0;
}

.input-group {
  margin-bottom: 20px;
}

.input-group label {
  display: block;
  margin-bottom: 8px;
  color: #555;
  font-size: 14px;
}

.input-group input {
  width: 100%;
  padding: 12px 16px;
  border: 2px solid #e0e0e0;
  border-radius: 8px;
  font-size: 16px;
  outline: none;
}

.input-group input:focus {
  border-color: #667eea;
}

#login-btn {
  width: 100%;
  padding: 12px;
  background: linear-gradient(135deg, #667eea, #764ba2);
  color: white;
  border: none;
  border-radius: 8px;
  font-size: 16px;
  cursor: pointer;
}

#login-btn:hover {
  opacity: 0.9;
}

/* Agent selection screen */
#screen-agents {
  flex-direction: column;
  background: #f5f5f5;
}

.sidebar-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 16px;
  padding: 16px 20px;
  background: white;
  border-bottom: 1px solid #e0e0e0;
}

.user-badge {
  min-width: 0;
  font-weight: 600;
  color: #333;
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}

#agent-list {
  flex: 1;
  overflow-y: auto;
  padding: 16px;
}

.empty-state {
  color: #777;
  font-size: 14px;
  text-align: center;
  padding: 48px 16px;
}

/* Agent cards */
.agent-card {
  display: flex;
  align-items: center;
  padding: 16px;
  background: white;
  border-radius: 12px;
  margin-bottom: 12px;
  cursor: pointer;
  box-shadow: 0 2px 8px rgba(0, 0, 0, 0.08);
}

.agent-card:hover {
  background: #f8f8ff;
}

.agent-avatar {
  flex: 0 0 auto;
  width: 48px;
  height: 48px;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 24px;
  background: linear-gradient(135deg, #667eea, #764ba2);
  color: white;
  margin-right: 16px;
}

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

.agent-name {
  font-weight: 600;
  font-size: 16px;
  color: #333;
}

.agent-id {
  font-size: 12px;
  color: #999;
  margin-top: 2px;
}

.agent-preview {
  font-size: 13px;
  color: #666;
  margin-top: 4px;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
  max-width: 100%;
}

.unread-badge {
  flex: 0 0 auto;
  background: #ff4444;
  color: white;
  font-size: 12px;
  min-width: 22px;
  padding: 2px 8px;
  border-radius: 12px;
  text-align: center;
  margin-left: 12px;
}

/* Chat screen */
#screen-chat {
  flex-direction: column;
}

.chat-header {
  display: flex;
  align-items: center;
  padding: 12px 16px;
  background: white;
  border-bottom: 1px solid #e0e0e0;
}

#back-btn {
  background: none;
  border: none;
  font-size: 24px;
  cursor: pointer;
  padding: 4px 12px 4px 4px;
  color: #667eea;
}

.chat-agent-info {
  display: flex;
  align-items: center;
  min-width: 0;
}

.chat-agent-info .agent-avatar {
  width: 36px;
  height: 36px;
  font-size: 18px;
  margin-right: 12px;
}

#chat-agent-name {
  font-weight: 600;
  font-size: 16px;
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}

/* Message list */
.message-list {
  flex: 1;
  overflow-y: auto;
  padding: 16px;
  background: #f0f2f5;
}

.message {
  display: flex;
  margin-bottom: 12px;
}

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

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

.message-content {
  max-width: min(70%, 720px);
}

.message-bubble {
  padding: 10px 16px;
  border-radius: 18px;
  font-size: 15px;
  line-height: 1.4;
  position: relative;
  overflow-wrap: anywhere;
  white-space: pre-wrap;
}

.message.user .message-bubble {
  background: #667eea;
  color: white;
  border-bottom-right-radius: 4px;
}

.message.agent .message-bubble {
  background: white;
  color: #333;
  border-bottom-left-radius: 4px;
  box-shadow: 0 1px 2px rgba(0, 0, 0, 0.1);
}

.message-time {
  font-size: 11px;
  color: #999;
  margin-top: 4px;
}

.message.user .message-time {
  text-align: right;
}

/* Chat input */
.chat-input-area {
  display: flex;
  padding: 12px 16px;
  background: white;
  border-top: 1px solid #e0e0e0;
}

#message-input {
  flex: 1;
  min-width: 0;
  padding: 10px 16px;
  border: 2px solid #e0e0e0;
  border-radius: 24px;
  font-size: 15px;
  outline: none;
  margin-right: 8px;
}

#message-input:focus {
  border-color: #667eea;
}

#send-btn {
  flex: 0 0 auto;
  padding: 10px 24px;
  background: linear-gradient(135deg, #667eea, #764ba2);
  color: white;
  border: none;
  border-radius: 24px;
  font-size: 15px;
  cursor: pointer;
}

#send-btn:hover {
  opacity: 0.9;
}

/* Logout button */
#logout-btn {
  flex: 0 0 auto;
  padding: 6px 16px;
  background: #ff4444;
  color: white;
  border: none;
  border-radius: 6px;
  cursor: pointer;
  font-size: 13px;
}

#logout-btn:hover {
  opacity: 0.9;
}

@media (max-width: 560px) {
  .login-container {
    padding: 28px 24px;
  }

  #agent-list {
    padding: 12px;
  }

  .agent-card {
    padding: 14px;
  }

  .message-content {
    max-width: 82%;
  }

  .chat-input-area {
    padding: 10px;
  }

  #send-btn {
    padding: 10px 18px;
  }
}