* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
  font-family: sans-serif;
}

body {
  width: 100%;
  height: 100vh;
  background-color: rgb(81, 52, 150);
  display: flex;
  align-items: center;
  justify-content: center;
}

.container {
  width: 300px;
  height: auto;
  padding: 15px;
  background-color: rgb(0, 0, 34);
  display: flex;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  gap: 15px;
  border-radius: 10px;
}

.container .display {
  width: 100%;
  height: 100px;
  padding: 5px 10px;
  border: 1px solid rgba(255, 255, 255, 0.103);
  border-radius: 10px;
  color: white;
  font-size: 2rem;
  display: flex;
  justify-content: right;
  align-items: end;
  overflow: hidden;
}

.container .buttons {
  width: 100%;
  height: 320px;
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  grid-template-rows: repeat(5, 1fr);
  gap: 8px;
}

.container .buttons .btn-equal {
  grid-column: 3 / 5;
  grid-row: 5;
}

button {
  border-radius: 15px;
  border: none;
  color: white;
  background-color: rgba(255, 255, 255, 0.014);
  transition: background .3s ease;
  font-weight: 500;
  font-size: 1rem;
}

button.btn-special {
  color: rgb(79, 28, 173);
}

button.btn-clear {
  color: rgb(99, 0, 0);
}

button.btn-equal {
  font-weight: 800;
  background: rgb(100, 0, 0);
}

button.btn-clear, button.btn-special {
  font-weight: 800;
  background-color: rgba(255, 255, 255, 0.034);
}

button:not(.btn-equal):hover {
  background: rgba(255, 255, 255, 0.075);
  cursor: pointer;
}

button.btn-equal:hover {
  background: rgb(51, 0, 0);
  cursor: pointer;
}