CSS Done

body {
    background: url(../img/main.jpg) no-repeat center fixed;
    background-size: cover;
}

.menu ul {
    list-style:none;
    padding: 0;
    margin: 0;
    text-align: center;
}

.menu li {
    border: 1px solid black;
    background-color: #4da6ff; /* Világoskék */
    width: 90px;
    text-align: center;
    display: inline-block;
}

.menu li a {
    display: block;
    color: white; /* Betuszín */
    padding: 12px;
    text-decoration: none;
}

.menu li a:hover {
    background-color: #ffdb4d; /* Világossárga*/
}

.menu .active {
    background-color: #4CAF50;
}

.menu {
    top: 20px;
    display: block;
    position: fixed;
    width: 100%;
}

.text p {
    margin: 80px 40px 20px 40px;
    padding: 10px;
    text-align:  justify;
    background-color: white;
       filter:alpha(opacity=50);
   -moz-opacity:0.7;
   opacity: 0.7;
   top: 80px;
   position: absolute;
   border: 1px solid;
}

.pTitle {
    margin: 106px 80px 200px 40px;
    padding: 10px;
    top: 90px;
    text-align: center;
    font-size: 30px;
        background-color: white;
       filter:alpha(opacity=50);
   -moz-opacity:0.9;
   opacity: 0.9;
   width: 260px;
   border: 1px solid;
   font-family: Arial;
}