Exemplo de opacidade do CSS
.opacity30 {
opacity: 0.3;
filter: alpha(opacity=30); /* For IE8 and earlier */
}
Grepper
.opacity30 {
opacity: 0.3;
filter: alpha(opacity=30); /* For IE8 and earlier */
}.div{
opacity: 0.8; /* 1 means fully visible, 0 means invisible */
}