html, body {
  margin: 0;
  padding: 0;
  height: 100%;
  font-family: 'Helvetica Neue', Helvetica, 'PingFang SC', 'Hiragino Sans GB', 'Microsoft YaHei', Arial, sans-serif;
}
#app {
  height: 100%;
  font-size: 14px;
  color: #2c3e50;
}