style.css

body {
  margin: 0;
  padding: 0;
  font-family: Arial, Monospace, sans-serif;
  background-color: rgb(32, 32, 32);
  /* This fancy gradient background is not written by me, I found it on Stack OverFlow. */
  background-image: linear-gradient(
      to right,
      rgba(0, 0, 0, 1),
      rgba(0, 0, 0, 0) 20%,
      rgba(0, 0, 0, 0) 80%,
      rgba(0, 0, 0, 1)
    ),
    linear-gradient(
      45deg,
      black 25%,
      transparent 25%,
      transparent 75%,
      black 75%,
      black
    ),
    linear-gradient(
      45deg,
      black 25%,
      transparent 25%,
      transparent 75%,
      black 75%,
      black
    ),
    linear-gradient(to bottom, rgb(8, 8, 8), rgb(32, 32, 32));
  background-size: 100% 100%, 10px 10px, 10px 10px, 10px 5px;
  background-position: 0px 0px, 0px 0px, 5px 5px, 0px 0px;
}

#top-bar {
  display: flex;
  flex: 1;
  justify-content: center;
  height: 7vh;
  font-size: 4em;
  color: #ff9900;
  text-transform: uppercase;
  font-weight: 600;
  padding: 0.5em;
  padding-top: 0.5em;
  white-space: pre-wrap;
}

#content-container {
  display: flex;
  justify-content: space-between;
  flex-wrap: wrap;
  width: 90%;
  margin-left: auto;
  margin-right: auto;
  color: #228dff;
}

#compare-button {
  display: flex;
  margin-left: auto;
  margin-right: auto;
  justify-content: center;
  text-transform: uppercase;
  font-size: 2.5em;
  margin-bottom: 1.5vh;
  font-weight: 600;
  padding: 0.1em 0.3em 0.1em 0.3em;
  border-radius: 0.1em;
  cursor: pointer;
  transition: all 0.25s;
  background-color: rgba(30, 30, 30, 0.3);
  border: 1px solid #fff;
  -moz-user-select: none;
  -khtml-user-select: none;
  -webkit-user-select: none;
  -ms-user-select: none;
  user-select: none;
}

#compare-button:hover {
  transform: scale(1.05);
  background-color: rgba(1, 1, 1, 1);
}

#compare-button:active {
  transform: scale(1);
}

textarea {
  width: 47%;
  height: 30vh;
  border-radius: 0.2em;
  font-size: 1.5em;
  padding: 0.5em;
  margin-bottom: 1.5vh;
  white-space: normal;
}

#output {
  width: 100%;
  font-size: 1.5em;
  text-align: left;
  color: black;
  background-color: #fff;
  height: 30vh;
  padding: 0.5em;
  overflow-y: scroll;
  overflow-x: hidden;
}

ins {
  text-decoration: none;
  background-color: #51cc09;
}

del {
  text-decoration: line-through;
  background-color: #ff1145;
  color: rgb(0, 0, 0);
}

h1 {
  text-align: center;
  margin: 1em;
}



h1 > a {
    text-decoration: none;
    color: #fff;
    font-size: 0.9em;
    font-weight: 600;
    letter-spacing: 0.1em;
    transition: letter-spacing 1s ease, color 1s ease;
}

h1 > a:hover {
    color: #2c92fe;
    letter-spacing: 0.3em;
    transition: letter-spacing 0.5s ease, color 0.5s ease;
}

@media (max-width: 769px) {
  #top-bar {
    font-size: 2em;
  }

  #content-container {
    width: 95%;
  }

  textarea {
    width: 100%;
  }

  #compare-button {
    font-size: 1.5em;
    margin-top: 1vh;
    margin-bottom: 1.5vh;
  }

  a {
    font-size: 0.7em;
  }
}