styles.css

body {
  display: flex;
  justify-content: center;
  align-items: center;
  margin: 40px;
  flex-direction: column;
  font-family: "verdana";
}
h1 {
  font-weight: bold;
  font-size: 3rem;
  letter-spacing: -4.5px;
}
form {
  margin: 20px;
}
canvas {
  border-top-left-radius: 10px;
  border-top-right-radius: 10px;
}
#palette,
#complementary {
  display: flex;
  justify-content: center;
  align-items: center;
  flex-wrap: wrap;
  width: 80%;
}

#palette div,
#complementary div {
  height: 120px;
  width: 120px;
  display: flex;
  justify-content: center;
  align-items: center;

  /* create a little bit of contrast for the text */
  mix-blend-mode: difference;
  color: #fff;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  text-shadow: 1px 1px #333;
}

#palette div,
#complementary div {
  height: 120px;
  width: 120px;
  display: flex;
  justify-content: center;
  align-items: center;
}