body {
  margin: 0;
  font-family: system-ui, sans-serif;
  display: flex;
  flex-direction: column;
  min-height: 100dvh;
  /* Set background and default text color */
  background-color: #000;
  color: #fff;
}

/* Center header and footer content */
header,
footer {
  text-align: center;
  padding: 2rem 1rem;
}

/* Make the main section a centered flex column */
main {
  flex: 1;
  display: flex;
  flex-direction: column;       /* stack children vertically */
  align-items: center;          /* horizontal centering */
  justify-content: center;      /* vertical centering */
  text-align: center;           /* center text inside */
  padding: 2rem;
}

/* Constrain paragraph width a bit for readability */
main p {
  max-width: 60ch; /* roughly 60 characters */
}

img.logo {
  max-width: 90%;
  height: auto;
}

a.mail {
  color: inherit; /* will be white because body text is white */
  text-decoration: none;
}