* {
  padding: -40;
  margin: 0;
}

.kontener {
  width: 500px;
  height: 600px;
  display: flex;
  justify-content: center;
  /*  box-shadow is from materialize css's website */
 /* box-shadow: 0 24px 38px 3px rgba(0, 0, 0, 0.14),
      0 9px 46px 8px rgba(0, 0, 0, 0.12), 0 11px 15px -7px rgba(0, 0, 0, 0.2); */
}

.kontener img {
  width: 100%;
  height: 100%;
  z-index: -2;
}

button {
  height: 10%;
  border: none;
  outline: none;
  background: rgba(0, 0, 0, 0.5);
  cursor: pointer;
  padding: 1em;
  display: flex;
}

button .arrow {
  border: solid #fff;
  border-width: 0 7px 7px 0;
  display: inline-block;
  padding: 11px;
  transition: transform 0.3s ease-out;
  outline: none;
}

#right-btn {
  margin: auto 0 auto -2em;
}

#right-btn .arrow {
  transform: rotate(-45deg);
}

#left-btn {
  z-index: 0;
  margin: auto -2em auto 0;
}

#left-btn .arrow {
  transform: rotate(135deg);
}