@font-face {
  font-family: calculator;
  src: url(digital-7.ttf);
}

@font-face {
  font-family: Roboto;
  src: url(Roboto-Regular.ttf);
}

:root {
  --display-equals: #4d5340;
  --main-background: #c6bba3;
  --btns-area-background: #979684;
  --calc-container: #1d1e18;
  --btn-font: #c6bba3;
}

html {
  font-size: 15px;
}

* {
  touch-action: manipulation;
}

body {
  font-size: 1rem;
  font-family: 'Roboto', Arial, Helvetica, sans-serif;
  background-color: var(--main-background);
}

h1 {
  font-size: 2rem;
  line-height: 2.2rem;
}

p {
  font-size: 1rem;
  line-height: 1.3rem;
}

.calc-container {
  width: 450px;
  margin: 4rem auto;
  border: 8px outset var(--calc-container);
  border-radius: 4px;
  box-shadow: 6px 8px var(--display-equals);
}

.display-container {
  display: flex;
  background-color: var(--calc-container);
}

#display {
  background: var(--display-equals);
  padding: 4px 12px;
  margin: 1rem;
  font-size: 3rem;
  flex: auto;
  text-align: end;
  font-family: 'calculator', monospace;
  font-weight: 100;
  pointer-events: none;
  border: 8px inset var(--calc-container);
  border-radius: 4px;
}

#info {
  margin: auto;
  width: 400px;
  display: grid;
  gap: 1rem;
}

.calculator-buttons {
  background-color: var(--btns-area-background);
  padding: 1rem;
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 1rem;
}

.clear-button {
  background: #934730;
}

button {
  color: var(--btn-font);
  background: rgb(80, 80, 80);
  background: linear-gradient(
    90deg,
    rgb(66, 66, 66) 0%,
    var(--calc-container) 100%
  );
  border: 8px solid var(--calc-container);
  border-radius: 8px;
  padding: 0.8rem;
  font-size: 1.2rem;
  font-weight: 600;
  font-family: Arial, Helvetica, sans-serif;
}

#equals {
  background: var(--display-equals);
  grid-column-start: 3;
  grid-column-end: span 2;
  color: var(--btn-font);
}

@media only screen and (max-width: 450px) {
  button {
    padding: 0.6rem 0.4rem;
    font-size: 1rem;
    border: 6px solid var(--calc-container);
    border-radius: 6px;
  }

  .calculator-buttons {
    gap: 0.7rem;
  }

  .calc-container {
    width: 350px;
    border: 6px outset var(--calc-container);
    border-radius: 4px;
    box-shadow: 6px 8px var(--display-equals);
  }

  #info {
    margin: auto;
    width: 300px;
    font-size: 1.2rem;
    line-height: 1.5rem;
    padding-bottom: 2rem;
  }
}