* { box-sizing: border-box; }

html, body {
  height: 100%;
  margin: 0;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Arial, sans-serif;
  background: #f0f2f5;
  overflow: hidden;
}

.screen {
  height: 100vh;
  height: 100dvh; /* учитывает мобильные панели браузера */
  display: flex;
  flex-direction: column;
}

.hidden {
  display: none !important;
}

/* Экран входа */
#login-screen {
  align-items: center;
  justify-content: center;
}

.login-box {
  background: #fff;
  padding: 32px 28px;
  border-radius: 12px;
  box-shadow: 0 4px 20px rgba(0,0,0,0.08);
  width: 280px;
  text-align: center;
}

.login-box h1 {
  margin: 0 0 20px;
  font-size: 20px;
  color: #222;
}

.login-box input {
  width: 100%;
  padding: 12px;
  border: 1px solid #ddd;
  border-radius: 8px;
  font-size: 16px;
  margin-bottom: 12px;
}

.login-box button {
  width: 100%;
  padding: 12px;
  border: none;
  border-radius: 8px;
  background: #2f7dff;
  color: #fff;
  font-size: 16px;
  cursor: pointer;
}

.login-box button:hover {
  background: #1f6de0;
}

.error {
  color: #e53935;
  font-size: 13px;
  min-height: 16px;
  margin: 8px 0 0;
}

/* Экран чата */
#messages {
  flex: 1;
  overflow-y: auto;
  padding: 16px;
  display: flex;
  flex-direction: column;
}

.message {
  max-width: 70%;
  padding: 10px 14px;
  border-radius: 16px;
  margin-bottom: 8px;
  font-size: 15px;
  line-height: 1.4;
  word-wrap: break-word;
  white-space: pre-wrap;
}

.message.own {
  align-self: flex-end;
  background: #2f7dff;
  color: #fff;
  border-bottom-right-radius: 4px;
}

.message.other {
  align-self: flex-start;
  background: #fff;
  color: #222;
  border-bottom-left-radius: 4px;
  box-shadow: 0 1px 2px rgba(0,0,0,0.08);
}

#message-form {
  display: flex;
  padding: 12px;
  padding-bottom: max(12px, env(safe-area-inset-bottom));
  gap: 8px;
  background: #fff;
  border-top: 1px solid #e2e2e2;
}

#message-input {
  flex: 1;
  padding: 12px;
  border: 1px solid #ddd;
  border-radius: 20px;
  font-size: 15px;
  outline: none;
}

#message-form button {
  padding: 0 20px;
  border: none;
  border-radius: 20px;
  background: #2f7dff;
  color: #fff;
  font-size: 15px;
  cursor: pointer;
  flex-shrink: 0;
}

#message-form button:hover {
  background: #1f6de0;
}

/* Мобильная адаптация */
@media (max-width: 600px) {
  .login-box {
    width: 100%;
    max-width: 320px;
    padding: 28px 22px;
  }

  #messages {
    padding: 12px 10px;
  }

  .message {
    max-width: 82%;
    padding: 9px 13px;
    font-size: 15px;
  }

  #message-form {
    padding: 10px;
    padding-bottom: max(10px, env(safe-area-inset-bottom));
  }

  #message-input {
    padding: 10px 12px;
    font-size: 16px; /* не меньше 16px, иначе iOS автоматически зумит при фокусе */
  }

  #message-form button {
    padding: 0 16px;
    font-size: 14px;
  }
}