style.css

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

* {
  margin: 0; 
  padding: 0;
  box-sizing: border-box;
  font-family: 'Poppins';
}

body {
  margin: 2rem 0;
}

h1 {
  margin-top: 1.5rem;
  text-align: center;
  font-size: 1.5rem;
  color: red;
}

#btns, #options, #find {
  display: flex; 
  justify-content: center;
  align-items: center;
}

button {
  padding: 0 0.5rem;
  margin: 0.5rem .7rem; 
  cursor: pointer;
}

input {
  margin: 0 .5rem;
  padding: .3rem;
  width: 45px;
  height: 30px;
  border-color: #f1f1f1;
  outline: none;
  margin: .5rem;
}

main {
  display: flex;
  justify-content: center;
  align-content: center;
}

#adjacencyMatrix {
  margin-top: 1.5rem;
  margin-bottom: 1rem;
}

@media only screen and (max-width: 425px) {
  h1 {
    font-size: 1.2rem;
  }
}