a{line-height:0;transition:color .4s ease-in}.underline{background-image:linear-gradient(#212121,#212121);background-image:linear-gradient(var(--dynamic-underline-color,var(--color-grey-900)),var(--dynamic-underline-color,var(--color-grey-900)));background-position:0 100%;background-repeat:no-repeat;background-size:0 1px;text-decoration:none;transition:background-size .6s cubic-bezier(.25,1,.5,1)}.underline:hover{background-size:100% 1px}