styles.css

:root {
  --main-max-width: 720px;
}

.navbar {
  font-size: 1.6em;
  font-weight: bold;
  margin-bottom: 20px;
  border: 3px solid #000;
  padding: 10px;
  display: flex;
  flex-wrap: wrap;
}
.navbar__col {
  margin-right: 5px;
  margin-left: 5px;
  display: flex;
  flex-direction: column;
  justify-content: center;
}
.navbar__image {
  height: 100%;
  width: 42px;
}
.navbar__link {
  color: #000;
}

.content {
  max-width: var(--main-max-width);
  margin: 0 auto;
  font-family: Arial;
  font-size: 18px;
  line-height: 1.4;
}

pre {
  font-size: 14px;
  overflow-x: auto;
}

.button {
  padding: .5em 1em;
  margin: 5px;
  border: 2px solid #000;
  border-radius: .5em;
  color: #fff;
  background-color: #000;
  text-decoration: none;
  user-select: none;
  cursor: pointer;
  font-family: -system-ui, sans-serif;
  font-size: 1em;
  line-height: 1.2;
  white-space: nowrap;
}

.button:hover {
  color: #555555;
  background-color: #fff;
  border: 2px solid #000;
}

img {
  max-width: 100%;
}