.order_nav .tt{ width:33.33%; text-align: center; line-height: 36px;box-sizing: border-box;}
.order_nav .tt.on { color: #02B4A8; position: relative;}
.order_nav .tt.on::after{content: ""; width: 40px; height: 2px;background: #02B4A8; position: absolute; bottom: 0;left: 50%;transform: translateX(-50%);}