css 线性渐变

background: linear-gradient(
to right,
rgba(0,0,0,0) 0%,
rgba(0,0,0,0) 10%,
rgba(35,198,200,0.3) 20%,
rgba(35,198,200,0.4) 30%,
rgba(35,198,200,0.5) 40%,
rgba(35,198,200,0.8) 50%,
rgba(35,198,200,0.5) 60%,
rgba(35,198,200,0.4) 70%,
rgba(35,198,200,0.3) 80%,
rgba(0,0,0,0) 90%,
rgba(0,0,0,0) 100%)