index.less

#app{
    --borderColor: whitesmoke;
    #app-main{
        .nav.nav-pills.nav-fill{
            background-color: transparent
        }
        .nav-pills:after{
            content: none
        }
        .nav-link.active{
            color:rgba(255,255,255,.8);
            box-shadow: none;
        }
        .nav-link::after{
            border-radius: 0;
            inset-block-end: -5px;
            inset-inline: 100%;
            border-bottom: 2px solid var(--borderColor);
            transition: inset-inline 1s var(--appleEase),
            display 1s var(--appleEase);
        }
        .nav-link:hover{
            box-shadow: none;
            color:rgba(255,255,255,.8);
            &::after{
                background: transparent;
                border-bottom: 2px solid var(--borderColor);
                inset-inline: 30%;
                transition: inset-inline 0.5s var(--appleEase);
            }
            
        }
        .nav-link.active::after{
            background: transparent;
            border-bottom: 2px solid var(--borderColor);
            inset-inline: 10%;
        }
    }
}