* {
  border: 0px;
  padding: 0px;
  font-family: monospace;
  background-color: #bcf3f0;
}

.title {
  text-align: center;
}

.introduction {
  text-align: center;
  font-size: 24px;
}

.entire-calculator-container {
  display: flex;
  justify-content: center;
  font-family: 'Courier New', Courier, monospace
}

.calculator-outline {
  display: flex;
  flex: 1;
  flex-direction: column;
  align-items: center;
  background-color: gray;
  height: 600px;
  width: 400px;
  border: 3px solid black;
  border-radius: 5px;
  
}

.calculator-screen {
  background-color: lightgreen;
  height: 100px;
  width: 90%;
  border-radius: 2px;
  border: 2px solid black;
  margin: 10px;
  font-size: 28px;
  font-family: monospace;
  text-align: left;
}

/* 
- buttons-flex-container 
  - buttons-row-flex-container
    - row
      - button (4x)
*/

.buttons-flex-container {
  display: flex;
  flex-direction: column;
}

.buttons-flex-container .buttons-row-flex-container {
  display: flex;
  flex-direction: row;
}

.row {
  display: flex;
  flex-direction: row;
  flex: 1;
  background-color: gray;
}

.row.top {
  justify-content: right;
}

.button {
  cursor: pointer;
  background-color: white;
  border-radius: 2px;
  text-align: center;
  font-size: 52px;
  border: 2px solid black;
  height: 80px;
  width: 80px;
  margin: 5px;
}

.button:active {
  background-color: lightgray;
}

.clear-button {
  background-color: lightblue;
}

.clear-button:active {
  background-color: blue;
}

.equals-button {
  background-color: lightgray;
}

.equals-button:active {
  background-color: darkslategray;
}

.operators {
  background-color: orange;
}

.operators:active {
  background-color: orangered;
}

.footer {
  text-align: center;
  margin-top: 50px;
}