:root {
  --5in-gap: 20px;
}

body {
  margin: 0;
  padding: 0;
}

.header {
  margin-bottom: calc(2 * var(--5in-gap));
}

.footer {
  margin-top: calc(2 * var(--5in-gap));
}

.center {
  max-width: 960px;
  margin-inline: auto;
}

.line {
  display: flex;
  justify-content: flex-start;
  align-items: center;
  gap: var(--5in-gap);
}