body {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  background-color: hsl(0, 0%, 77%);
}
h1 {
  color: #0b2447;
  font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
}

#calc-container {
  display: flex;
  flex-wrap: wrap;
  width: 290px;
  border: 2px solid;
  padding: 10px;
  border-radius: 5px;
  background-color: #0b2447;
  align-items: center;
  justify-content: center;
  font-family: 'Trebuchet MS', 'Lucida Sans Unicode', 'Lucida Grande',
    'Lucida Sans', Arial, sans-serif;
}
.calc-btn {
  aspect-ratio: 1 / 1;
  width: 65px;
  border: 1px solid;
  border-radius: 5px;
  font-size: 1.8rem;
  margin: 3px;
  background-color: #a5d7e8;
  font-family: 'Trebuchet MS', 'Lucida Sans Unicode', 'Lucida Grande',
    'Lucida Sans', Arial, sans-serif;
}

.op-btn {
  color: #005c73;
  font-weight: bolder;
}

#backspace,
#clear-btn {
  color: rgb(180, 0, 0);
}

button:active {
  transform: translateY(3px);
}

#display-container {
  width: 100%;
  height: 100px;
  border: 1px solid black;
  padding: 10px;
  font-size: 1.2rem;
  margin-bottom: 5px;
  color: #1fc742;
  background-color: #005118;
}

a {
  color: black;
  font-size: 3rem;
  margin-top: 1rem;
}

@media screen and (min-width: 768px) {
  #display-container {
    font-size: 1.8rem;
  }

  .calc-btn {
    aspect-ratio: 1 / 1;
    width: 70px;
    border: 1px solid;
    border-radius: 5px;
    font-size: 1.8rem;
    margin: 3px;
    background-color: #a5d7e8;
    font-family: 'Trebuchet MS', 'Lucida Sans Unicode', 'Lucida Grande',
      'Lucida Sans', Arial, sans-serif;
  }
  #calc-container {
    display: flex;
    flex-wrap: wrap;
    width: 380px;
    border: 2px solid;
    padding: 10px;
    border-radius: 5px;
    background-color: #0b2447;
    align-items: center;
    justify-content: center;
    font-family: 'Trebuchet MS', 'Lucida Sans Unicode', 'Lucida Grande',
      'Lucida Sans', Arial, sans-serif;
  }
}