styles.css

*,
*::before,
*::before {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

html,
body {
  font-size: 62.5%;
  font-family: system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto,
    Oxygen, Ubuntu, Cantarell, "Open Sans", "Helvetica Neue", sans-serif;
  line-height: 1.5;
  background-color: #ef8787;
}

.calculator {
  display: flex;
  height: 100vh;
  flex-direction: column;
  justify-content: flex-start;
  margin-top: 1rem;
  align-items: center;
}

.heading {
  font-size: 1.5rem;
  margin-bottom: 1rem;
  text-decoration: underline;
  color: dodgerblue;
  font-weight: 700;
  padding-left: 3.6rem;
}

#screen {
  padding: 2.5rem 1.5rem;
  font-size: 2.5rem;
  border: 1px solid dodgerblue;
  outline: none;
  border-radius: 6px;
  cursor: pointer;
  color: white;
  width: 85%;
  background-color: dodgerblue;
  margin: 2.5rem;
}

.row .btn {
  margin: 1.3rem;
  padding: 1.5rem 1rem;
  font-size: 2rem;
  width: 5rem;
  border: 1px solid dodgerblue;
  outline: none;
  border-radius: 6px;
  cursor: pointer;
  color: white;
  background-color: dodgerblue;
  transition: all 0.8s ease-out;
}

.btn:hover,
#screen:hover {
  color: dodgerblue;
  box-shadow: 0 0 1.2rem dodgerblue;
  outline: none;

  background-color: white;
}

.screen,
.rows {
  background-color: #f7f0f0;
  border: 2px solid blue;
  border-radius: 2rem 2rem 0 0;
  border-collapse: collapse;
  padding: 2rem;
}

.rows {
  border-top: 0;
  border-radius: 0rem 0 2rem 2rem;
  padding: 2rem 6.1rem;
}

@media screen and (max-width: 468px) {
}