styles.css

@import url('https://fonts.googleapis.com/css2?family=Monoton&family=Teko&display=swap');

body {
  text-align: center;
  margin: 0 auto;
  padding: 0;
  width: 100%;
  min-width: 390px;
  background-color: #fff;
  font-size: 20px;
  letter-spacing: 2px;
  font-family: 'Teko', sans-serif;
  color: #545454;
  overflow: hidden;
}

h1 {
  margin-top: 3vh;
  font-family: 'Monoton', cursive;
  font-size: 2.3rem;
}

#container {
  display: grid;
  grid-template-columns: repeat(var(--grid-rows), auto);
  grid-template-rows: repeat(var(--grid-columns), auto);
  width: 500px;
  height: 500px;
  margin: 7vh auto 0 auto;
  border: solid 2px #d5d5d5;
  box-shadow: 5px 5px 30px 5px #e5e5e5;
}

.square {
  border: solid 1px #f1f1f1;
}

#options {
  display: flex;
  justify-content: space-around;
  flex-wrap: wrap;
  align-content: center;
  width: 70%;
  max-width: 500px;
  margin: 8vh auto;
}

.option {
  width: 30%;
  padding: 5px;
  margin: 0 auto 10px auto;
  border: solid 2px #d5d5d5;
  border-radius: 4px;
  box-shadow: 2px 4px 10px #d5d5d5;
  cursor: pointer;
}

.option:hover {
  background-color: #f6f6f6;
  transition: 0.25s;
}

#size:active {
  transform: translate(0px, 1px);
  box-shadow: none;
}

#clear:active {
  transform: translate(0px, 1px);
  box-shadow: none;
}

input {
  font-family: 'Teko', sans-serif;
  font-size: 1rem;
  letter-spacing: 2px;
  text-align: center;
  border: solid 1px #d5d5d5;
  color: #545454;
}

@media screen and (max-width: 555px) {
  h1 {
    margin-top: 10vh;
  }
  #container {
    width: 400px;
    height: 400px;
  }
}

@media screen and (max-width: 420px) {
  #container {
    width: 300px;
    height: 300px;
  }
}