.hl {
    color: #ffd274;
    position: relative;
    display: inline-block;
}
.hl::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 0;
    height: 1px;
    width: 100%;
    background: linear-gradient(90deg, transparent, #f0c050, transparent);
    opacity: 0;
    transition: opacity .3s;
}
.hl:hover {
    color: #ffd966;
    text-shadow: 0 0 8px rgba(255,200,60,.5), 0 0 20px rgba(255,180,40,.25);
}
.hl:hover::after { opacity: 1; }