body { margin:0; background:#000; }
.gallery-shell { display:flex;position:relative; width:100%; height:100%;  justify-content: center; }
.nav-peek {
  position:absolute;
  top:50%;
  transform:translateY(-50%) scale(0.85);
  width:10%;
  height:70%;
  background:#fff;
  border-radius:1em;
  box-shadow:0 1em 2em rgba(0,0,0,0.4);
  display:flex;
  align-items:center;
  justify-content:center;
  opacity:0.7;
  transition:0.25s;
  text-decoration:none;
  z-index:10;
}
.nav-peek.prev { left:-5%; transform:translateY(-50%) scale(0.85) rotateY(10deg); }
.nav-peek.next { right:-5%; transform:translateY(-50%) scale(0.85) rotateY(-10deg); }
.nav-peek:hover { opacity:1; transform:translateY(-50%) scale(0.92); }
.peek-inner { color:#333; font-weight:bold; }