* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
  font-family: "Poppins", sans-serif;
  border: none;
  outline: none;
}

body {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  min-height: 100vh;
  background: #424242;
  color: #fff;
}

main {
  width: 100%;
  max-width: 400px;
  height: auto;
  padding: 1rem;
  background-color: #222;
  border-radius: 10px;
  box-shadow: 0 0 10px rgba(0, 0, 0, 0.2);
}

h1 {
  font-size: 2.2rem;
  font-weight: 500;
  margin-bottom: 1rem;
  padding: 0.6rem 2rem;
  border-radius: 5px;
  background-color: #2222226b;
  border: solid 2px #000000;
}

h2 {
  font-size: 1.8rem;
  font-weight: 500;
  margin-bottom: 1rem;
  text-align: center;
}

.visor {
  display: flex;
  align-items: center;
  justify-content: center;
  text-align: right;
  padding-right: 1rem;
  margin-bottom: 1rem;
  width: 100%;
  height: 60px;
  border-radius: 5px;
  background-color: #f0f0f0;
  font-size: 1.8rem;
}

.visor::placeholder {
  font-size: 1.5rem;
  color: rgba(0, 0, 0, 0.411);
}

.buttons {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 7px;
  height: auto;
}

.equal {
  height: auto;
  width: 100%;
  grid-column: span 2;
  background-color: #009292;
}

.equal:hover {
  background-color: #00bdbd;
}

button {
  padding: 10px;
  font-size: 1.2rem;
  font-weight: 500;
  cursor: pointer;
  transition: 0.2s;
  background-color: #7e7e7e;
  color: #fff;
}

button:hover {
  opacity: 0.9;
}