* {
  margin: 0px;
  padding: 0px;
  box-sizing: border-box;
}

body {
  height: 100vh;
  width: 100vw;
  display: grid;
  justify-content: center;
  align-items: center;
  background-color: #0c0c0c;
}

div {
  background: linear-gradient(191.34deg, #17181a -4.95%, #17181a 103.74%);
  width: 375px;
  height: 588px;
  border-radius: 35px;
  padding: 20px;
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  grid-template-rows: repeat(7, 1fr);

  @media screen and (max-width: 375px) {
    width: 350px;
  }
}

input {
  font-size: 48px;
  background-color: #1c1c1c;
  color: #fff;
  border: none;
  outline: none;
  text-align: right;
  padding-top: 50px;

  grid-row: 1/3;
  grid-column: 1/5;
}

button {
  font-size: 24px;
  border: none;
  margin: 7px;
  border-radius: 10px;
  color: #fff;

  &:hover {
    cursor: pointer;
    opacity: 0.7;
  }
}

.black-button {
  background-color: #303136;
}

.blue-button {
  background-color: #005db2;
}

.equal {
  background-color: #1991ff;
  grid-row: 6/8;
  grid-column: 4/5;
}

.gray-button {
  background-color: #616161;
}

.zero {
  grid-column: 1/3;
}