:root {
  #header header {
    box-sizing: border-box;
  }

  body {
    margin: 0 auto;
    width: clamp(375px, 100%, 1920px);
  }
}

@media (prefers-color-scheme: light) {
  :root {
    background-color: #f3f4f9;
  }
}

@media (prefers-color-scheme: dark) {
  :root {
    background-color: #1b1d29;
  }
}