style.css

body {
    background-color: black;
    background-repeat: no-repeat;
    background-attachment: fixed;
}

/* This class is already present in Bootstrap navbar. No need to add maually */
.navbar {
    background: rgba(255,255,255,0.2) !important;  /* Give transparent white background to navbar */
                                                   /* 0.2 to give little whitish effect. */
                                                   /* Put 0 to get complete transperency */
    z-index: 2;
    backdrop-filter: blur(10px) saturate(125%);                   /* Blur the background */
                                                                  /* 10px Gaussian Blur and saturate for fluent design */
    -webkit-backdrop-filter: blur(10px) saturate(125%);           /* Increases browser compability (safari ios and mac) */
}


/* Add the rest of page in div with this class. Use this class accordingly. It is not necessary */
.main-content {
    color: #fff;
    margin-top: 60px;
}


/* Below code in only needed if you have dropdown in navbar and want to change its fore and back colors */
.navbar-nav > li > .dropdown-menu { 
    background-color: #000000; 
}

.navbar-nav > li > .dropdown-menu > a{ 
    color: white;
}