cover.css

/*
 * Globals
 */

.clear {
  clear: both;
}

 .imgcontainer {
   position: relative;
 }

 .image {
   display: block;
   width: 100%;
   height: auto;
 }

 .imgoverlay {
   position: absolute;
   top: 0;
   bottom: 0;
   left: 0;
   right: 0;
   height: 100%;
   width: 100%;
   background: rgba(50,50,50,0.8);
   box-shadow: inset 0 0 5rem rgba(0, 0, 0, .5);
 }

 .text {
   color: white;
   font-size: 20px;
   position: absolute;
   top: 50%;
   left: 50%;
   -webkit-transform: translate(-50%, -50%);
   -ms-transform: translate(-50%, -50%);
   transform: translate(-50%, -50%);
   text-align: center;
 }

.card {
  background-color: #222 !important;
  float: left;
  margin: 10px;
}
/* Links */
a,
a:focus,
a:hover {
  color: #fff;
}

/* Custom default button */
.btn-secondary,
.btn-secondary:hover,
.btn-secondary:focus {
  color: #333;
  text-shadow: none; /* Prevent inheritance from `body` */
  background-color: #fff;
  border: .05rem solid #fff;
}


/*
 * Base structure
 */

html,
body {
  min-height: 100vh;
  height: 100%;
  background-color: #333;
}

body {
  display: -ms-flexbox;
  display: flex;
  color: #fff;
  text-shadow: 0 .05rem .1rem rgba(0, 0, 0, .5);
}

.cover-container {
  max-width: 57em;
}


/*
 * Header
 */
.masthead {
  margin-bottom: 2rem;
}

.masthead-brand {
  margin-bottom: 0;
}

.nav-masthead .nav-link {
  padding: .25rem 0;
  font-weight: 700;
  color: rgba(255, 255, 255, .5);
  background-color: transparent;
  border-bottom: .25rem solid transparent;
}

.nav-masthead .nav-link:hover,
.nav-masthead .nav-link:focus {
  border-bottom-color: rgba(255, 255, 255, .25);
}

.nav-masthead .nav-link + .nav-link {
  margin-left: 1rem;
}

.nav-masthead .active {
  color: #fff;
  border-bottom-color: #fff;
}

@media (min-width: 63em) {
  .masthead-brand {
    float: left;
  }
  .nav-masthead {
    float: right;
  }
}


/*
 * Cover
 */
.cover {
  padding: 0 1.5rem;
}
.cover .btn-lg {
  padding: .75rem 1.25rem;
  font-weight: 700;
}


/*
 * Footer
 */
.mastfoot {
  color: rgba(255, 255, 255, .5);
}