header {position: absolute; width: 100%; padding: 25px 0; z-index: 5;}
header .logo {width: 99px; height: auto;}
header .logo img {width: 100%; height: auto;}

/* fixed-btn */
.fixed-btn {position: fixed; bottom: 30px; right: 30px; z-index: 5;}
.fixed-btn a {display: block; width: 110px; height: auto;}
.fixed-btn a img {width: 100%; height: auto; box-shadow: 0 4px 25px 0 rgba(0, 0, 0, 0.15); border-radius: 100%;}
.fixed-btn:hover a img {animation: heartbeat 1.5s ease-in-out infinite both;}
@keyframes heartbeat {
  from {
    -webkit-transform: scale(1);
            transform: scale(1);
    -webkit-transform-origin: center center;
            transform-origin: center center;
    -webkit-animation-timing-function: ease-out;
            animation-timing-function: ease-out;
  }
  10% {
    -webkit-transform: scale(0.91);
            transform: scale(0.91);
    -webkit-animation-timing-function: ease-in;
            animation-timing-function: ease-in;
  }
  17% {
    -webkit-transform: scale(0.98);
            transform: scale(0.98);
    -webkit-animation-timing-function: ease-out;
            animation-timing-function: ease-out;
  }
  33% {
    -webkit-transform: scale(0.87);
            transform: scale(0.87);
    -webkit-animation-timing-function: ease-in;
            animation-timing-function: ease-in;
  }
  45% {
    -webkit-transform: scale(1);
            transform: scale(1);
    -webkit-animation-timing-function: ease-out;
            animation-timing-function: ease-out;
  }
}