.nav_head.scroll{
    top: 0;
    opacity: 1;

}

.nav_head{
    width: 100%;
    height: 6vh;
    position: fixed;
    top: -6vh;

    background-color: #0a0a0a;

    transition: all 0.4s ease-in-out;
    z-index: 4;
}

.ul_head{
    height: 6vh;
    width: 70%;
    min-width: 500px;
    display: flex;
    align-items: center;
    justify-content: space-around;
    margin: auto;
}

.a_head{
    position: relative;
    text-decoration: none;
    font-family: 'Poppins', sans-serif;
    color: #a0a0a0;
    font-size: 18px;
    letter-spacing: 0.5px;
    padding: 0 7px;
    cursor: pointer;
}

.a_head:after{
    content: "";
    position: absolute;
    background-color: rgb(150, 204, 134);
    height: 3px;
    width: 0;
    left: 0;
    bottom: -4px;
    transition: 0.3s;
}
.a_head:hover{
    color: white;
}

.a_head:hover:after{
    width: 100%;
}