:root {
  --font-Title: "Montserrat", sans-serif;
  --font-Heading: "Montserrat Alternates", sans-serif;
  --font-Paragraph: "Poppins", sans-serif;

  --font-weight-thin: 300;
  --font-weight-regular: 400;
  --font-weight-bold: 700;
  --font-weight-black: 900;
}

body {
  font-family: var(--font-Paragraph);
}

a,
a:hover,
a:focus,
a:visited {
  text-decoration: none;
}

.container {
  max-width: 400px;
  margin: 10vh auto 0 auto;
  box-shadow: 0px 0px 43px 17px rgba(153, 153, 153, 1);
}

#display {
  text-align: right;
  height: 70px;
  line-height: 70px;
  padding: 16px 8px;
  font-size: 1.5625rem;
  border-left: 1px solid #999;
  border-top: 1px solid #999;
  border-right: 1px solid #999;
}

.buttons {
  display: grid;
  border-bottom: 1px solid #999;
  border-left: 1px solid #999;
  border-right: 1px solid #999;
  grid-template-columns: 1fr 1fr 1fr 1fr;
  -webkit-tap-highlight-color: rgba(0, 0, 0, 0);
}

.button {
  border: 0.5 px solid #999;
  line-height: 100px;
  text-align: center;
  font-size: 1.5625rem;
  cursor: pointer;
}

#equal {
  background-color: tomato;
  color: white;
}

.button:hover {
  background-color: #1b1b1b;
  color: white;
  transition: 100ms ease-in-out;
}

#equal:hover {
  background-color: rgb(255, 76, 44);
  color: white;
  transition: 100ms ease-in-out;
}

h1 {
  text-align: center;
}

.by-me {
  display: flex;
  justify-content: center;
  align-items: center;
}

.by-me a {
  padding: 1rem;
  color: tomato;
  border-radius: 25px;
}

.by-me a:hover {
  color: aqua;
  transition: 100ms ease-in-out;
}