body {
  height: 100vh;
  margin: 0px;
}
main {
  display: flex;
  height: 100%;
  background-color: #d9d9d9;
}

#calculator {
  margin: auto;
  width: 20%;
  height: 70%;
  padding: 1%;
  display: flex;
  flex-direction: column;
  justify-content: space-evenly;
  border-radius: 50px;
  background: #f3f1f1;
  box-shadow: 20px 20px 60px #9e9d9d, -20px -20px 60px #ffffff;
}

#input {
  width: 95%;
  margin: 0 auto;
  display: flex;
  height: 15%;
  justify-content: center;
  font-size: 2rem;
  font-weight: bold;
  color: #0b254e;
  text-align: center;
  overflow: scroll;
  outline: none;
  border: none;
  box-sizing: border-box;

  background: #e8eaec;
  border-radius: 10px;
  padding: 12px;
  box-shadow: 6px 6px 8px rgba(13, 39, 80, 0.25), -6px -6px 10px #fff,
    inset -8px -8px 12px rgba(255, 255, 255, 0.7),
    inset 5px 5px 8px rgba(13, 39, 80, 0.2);
}
.btn-wrap {
  height: 70%;
  display: grid;
}

.btn-row {
  height: 80%;
  display: flex;
  justify-content: space-around;
}
.btn {
  width: 20%;
  height: 100%;
  margin: 1%;
  border: 0px;
  border-radius: 9px;
  background: #fbfdfe;
  box-shadow: 6px 6px 12px #dddfe0, -6px -6px 12px #ffffff;
  transition: all 1s;
  font-size: 1.5rem;
  font-weight: bold;
  color: #0b254e;
}

.btn:hover {
  border-radius: 9px;
  background: linear-gradient(145deg, #e2e4e5, #ffffff);
  box-shadow: 6px 6px 12px #dddfe0, -6px -6px 12px #ffffff;
}
.btn:active {
  border-radius: 9px;
  background: #fbfdfe;
  box-shadow: inset 6px 6px 12px #dddfe0, inset -6px -6px 12px #ffffff;
}