.milestone-background {
    position: relative;
    margin: 10px;
    border-radius: 20px;
    overflow: hidden; /* overlay stays inside border */
    background-attachment: fixed;
}

/* Overlay */
.milestone-background::before {
    content: "";
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background-color: #001f36d1; 
    border-radius: 10px;
    z-index: 0;
}

/* Content */
.milestone-background > .container {
    position: relative; /* above overlay */
    z-index: 1;
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    height: 100%;
    text-align: center;
    color: #fff; 
}