body {
  padding: 0 15px;
  margin-bottom: 100px;
}

[data-bs-theme="dark"] header img {
  filter: invert(100%);
}

.container {
  padding: 0;
}

@media (min-width: 768px) {
  .container {
    max-width: 768px;
  }
}

h1 {
  font-size: 4em;
}

h2 {
  border-bottom: 1px solid #ccc;
  margin-top: 2em;
  padding-bottom: 0.125em;
}

input:invalid {
  border-color: red;
}