style.css

@import url("https://fonts.googleapis.com/css2?family=New+Tegomin&display=swap");

:root {
  --title: #333;
  --background: #ededed;
  --button-border: #333;
  --button: #555;
  --button-hover: #444;
  --button-active: #333;
  --border: #222;
}

*,
*::before,
*::after {
  box-sizing: border-box;
  padding: 0;
  margin: 0;
}

html {
  font-family: "Roboto", sans-serif;
  font-size: 62.5%;
  line-height: 1.6;
}

body {
  background-color: var(--background);
  font-size: 1.6rem;
  text-align: center;
}

header {
  margin-top: 3rem;
  font-family: "New Tegomin", serif;
  padding: 2rem;
  font-size: 3.2rem;
}

h1 {
  line-height: 1.2;
}

.title {
  color: var(--title);
}

.container {
  padding: 1rem;
}

button {
  box-shadow: 0px 0px 0px 0px #ffffff;
  background-color: #ededed;
  border-radius: 28px;
  border: 1px solid #dcdcdc;
  display: inline-block;
  cursor: pointer;
  color: #777777;
  font-family: Arial;
  font-size: 17px;
  padding: 16px 22px;
  text-decoration: none;
  text-shadow: 0px 1px 0px #ffffff;
  outline: none;
}

button:hover {
  background-color: #dfdfdf;
}

button:active {
  position: relative;
  top: 1px;
}

.grid {
  display: grid;
  max-width: 500px;
  min-height: 500px;
  margin: 2rem auto;
  border: 2px solid var(--border);
}

.grid-element {
  border: 1px solid var(--border);
  background-color: var(--background);
}

@media (max-width: 450px) {
  header {
    font-size: 2.4rem;
  }

  .grid {
    max-width: 300px;
    min-height: 300px;
  }
}