stylesheet.css

* {
  margin: 0;
  padding: 0;
}

body {
  display: flex;
  justify-content: center;
  align-items: center;
  height: 100vh;
  background-color: #d3d4cf;
}

.second-table {
  width: 500px;
  height: 700px;
  background-color: #000;
  color: #fff;
  font-size: 28px;
  text-align: center;
  font-weight: 600;
  font-family: Arial, Helvetica, sans-serif;
  transform: scale(0.7);
  box-shadow: 0px 10px 10px -5px black;
}

.second-table {
  padding: 20px;
}

.second-table tr td {
  width: 100px;
  height: 100px;
}

.second-table .total {
  background-color: #000;
  border-radius: 0;
  text-align: right;
  padding-right: 20px;
}

.zero {
  width: 200px;
  height: 90px;
  border-radius: 50px;
}

button {
  border-radius: 100%;
  width: 95px;
  height: 95px;
  background-color: #333333;
  border: 0;
  color: #fff;
  font-size: 28px;
  font-family: Arial, Helvetica, sans-serif;
  outline: none;
}

button: hover {
    background-color: #5b5a5a;
    cursor: pointer;
}

.aaa {
    background-color: #a5a5a5;
}

.aaa: hover {
    background-color: #efe7e7;
}

.mobile-operation {
    background-color: #fe9e09;
}

.mobile-operation:hover {
    background-color: #ffc366;
}

.second-table .total {
    font-size: 34px;
}