.container {  position: relative; }

.container{
    content: "";
    position: absolute;
    top: 0;
    bottom: 0;
    left: 0;
    right: 0;
    z-index: -1;
    /*background-image: url('BG.png');*/
    background-size: 2000px 700px;
    background-repeat: no-repeat;
    background-attachment: fixed;
    opacity: 0.60;
}

.content {
    position: relative; 
    margin-top: 300px;
    font-size: 60px;
    opacity: 20;
    z-index: 1;
}​

.tool1 {
    margin-top: 680px;
    background-color: green;
    z-index: 1;
}

.tool2 {
    margin-top: 700px;
    background-color: #5DBCD2;
    z-index: 2;
}

.tool3 {
    margin-top: 720px;
    background-color: #5DBCD2;
}

.tool4 {
    margin-top: 720px;
    background-color: #5DBCD2;
}