style.css

#calculator {
  direction: ltr;
  width: 300px;
  display: flex;
  flex-wrap: wrap;
  justify-content: space-between;
}

#output-container {
  flex-basis: 100%;
  display: flex;
}

input {
  flex-basis: 100%;
}

#reset {
  flex-shrink: 0;
}

#numbers {
  display: flex;
  flex-wrap: wrap-reverse;
  flex-basis: 75%;
  flex-grow: 1;
}

#operators {
  display: flex;
  flex-direction: column-reverse;
}

input, button {
  height: 50px;
  margin: 3px;
  font-size: larger;
}

button {
  width: 50px;
  border: 1px solid brown;
  background-color: #FFe900;
}

button:hover {
  background-color: sandybrown;
  color: white;
}

#calculate:hover {
  background-color: darkblue;
}


#numbers button {
  flex-basis: calc(33% - 6px);
}

#calculate, #dot, #zero {
  order: -1;
}

#calculate {
  font-weight: bold;
  background-color: lightblue;
  border-color: darkblue;
}