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

.kalkulator {
  width: 100%;
  background: #eaeaea;
  padding: 7px;
  border-radius: 5px;
  height: 100vh;
  display: flex;
  flex-direction: column;
}

#layar {
  width: 100%;
  box-sizing: border-box;
  border: 1px solid #cecece;
  font-size: 25px;
  font-weight: bold;
  color: gray;
  padding: 10px 5px;
  text-align: right;
  outline: none;
  height: 80%;
  resize: none;            /* agar tidak bisa diubah ukurannya */
  overflow: hidden;        /* sembunyikan scroll bar */
}


.container-tombol {
  display: flex;
  flex-wrap: wrap;
}

.tombol {
  display: flex;
  width: 25%;
  font-size: 20px;
  color: gray;
  font-weight: bold;
  height: 70px;
  border: 1px solid #cecece;
  box-sizing: border-box;
  justify-content: center;
  align-items: center;
  border-top: none;
  border-left: none;
}

.tombol:nth-child(4n + 1) {
  border-left: 1px solid #cecece;
}

.tombol:hover {
  background: #e4e4e4;
  cursor: pointer;
}

#nol {
  flex-grow: 1;
}

.operator {
  background: #d8d8d8;
}

.hitung {
  background: #ffa64a;
  color: white;
}

.hitung:hover {
  background: orange;
}