body {
  display: grid;
  height: 100vh;
  width: 100vw;
  align-items: center;
  align-content: center;
  justify-content: center;
}

.slider {
  position: relative;
  width: 600px;
  height: 300px;
  transform: scale(0.8);
  overflow: hidden; /* remove overflow to see what's going on*/
}

.slide {
  position: absolute;
  width: 100%;
  height: 100%;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: transform 1s;
}

.slide b {
  position: absolute;
  font-size: 10em;
  color: black;
  opacity: 0.6;
  width: 100%;
  height: 100%;
  display: flex;
  align-items: center;
  justify-content: center;
}

.s1 {
  background-color: cornflowerblue;
}

.s2 {
  background-color: bisque;
}

.s3 {
  background-color: coral;
}

.s4 {
  background-color: thistle;
}

.btn {
  position: absolute;
  top: 50%;
  z-index: 10;
  border: none;
  background: crimson;
  font-family: inherit;
  color: white;
  height: 5.5rem;
  width: 5.5rem;
  font-size: 3.25rem;
  cursor: pointer;
}

.btn-left {
  left: 6%;
  transform: translate(-50%, -50%);
}

.btn-right {
  right: 6%;
  transform: translate(50%, -50%);
}