环境变量函数env()
<meta name="viewport" content="viewport-fit=cover">padding-left: env(SAFE-AREA-INSET-LEFT, 50px);calc
// 适配iPhoneX safe area
/* stylelint-disable */
@mixin x-padding-bottom($val:0px) {
padding-bottom: $val;
padding-bottom: calc(#{$val / 2} + constant(safe-area-inset-bottom)); /* no */
padding-bottom: calc(#{$val / 2} + env(safe-area-inset-bottom)); /* no */
}