styles.css

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

body {
  font-size: 16px;
  font-family: Roboto;
  background-color: #f2f5ea;
}

.whole-page {
  width: 100vw;
}

.container {
  margin: 4em auto 0;
  width: 420px;
  background-color: #815355;
  padding: 20px;
  border-radius: 0.5em;
  box-shadow: 10px 10px#523249;
}
.top-row {
  display: flex;
  justify-content: space-evenly;
}
.top-row-button {
  flex: 1;
  border-radius: 0.5em;
  background-color: #c3b299;
  text-align: center;
  font-size: 5;
  margin: 10px 20px;
  padding: 10px;
  cursor: pointer;
  box-shadow: 5px 5px #523249;
}

.top-row-button:active {
  box-shadow: none;
}
.row {
  overflow: auto;
}
.row:after {
  content: "";
  clear: both;
  display: table;
}
#output {
  background-color: #dbebc0;
  width: 100%;
  height: 40px;
  border-radius: 0.5em;
  padding-right: 10px;

  font-size: 30px;
}
.button {
  display: inline-block;
  float: left;
  width: 85px;
  line-height: 35px;
  text-align: center;
  border-radius: 0.5em;
  background-color: #cbd4c2;
  cursor: pointer;
  margin: 5px;
  overflow: auto;
}
.button:after {
  content: "";
  clear: both;
  display: table;
}
.button:hover {
  box-shadow: 0px 0px 15px #523249;
  background-color: #c3b299;
}
.button:active {
  color: white;
}
#output {
  text-align: right;
}