@import url('https://fonts.googleapis.com/css2?family=Poppins&display=swap');

* {
  box-sizing: border-box;
}

body {
  font-family: 'Poppins', sans-serif;
  background-color: #173f5f;
}

.flex-container-col {
  display: flex;
  flex-direction: column;
  max-width: 800px;
  margin: 0 auto;
  text-align: right;
}

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

.button {
  flex-basis: 25%;
  font-size: 1.5em;
  text-align: center;
  padding: 20px;
  margin: 0.3em 0.5em;
  border: 1px solid black;
  border-radius: 5px;
  background: #f6d55c;
  cursor: pointer;
}

.button:hover {
  font-weight: bold;
}

.display {
  width: 100%;
  padding: 2px 20px;
  margin-bottom: -25px;
  font-size: 2em;
  color: #f6d55c;
}

.operator,
.negative,
.clear,
.equal {
  background-color: #ed553b;
}

.card {
  box-shadow: 0 4px 8px 0 rgba(0, 0, 0, 0.2);
  border-radius: 5px;
  background-color: #20639b;
  padding: 30px;
  margin-top: 20px;
}

.footer {
  margin: 0 auto;
  margin-top: 10px;
  text-align: center;
  color: #f6d55c;
}

.footer a {
  text-decoration: none;
  color: #f6d55c;
}

@media screen and (max-width: 513px) {
  .button {
    padding: 10px;
  }
}