/* A content page is one reading column: its text, boxes and card grids all stop at
   42rem (app.css). Left-aligned in the 72rem layout that column left a wide empty
   strip on the right of a desktop screen; centred, the empty space splits evenly and
   the page sits balanced under the header. Title and body share the column, so they
   keep one left edge. The children inside keep margin 0 and simply fill it. */
h1,
article,
p {
    max-width: 42rem;
    margin-inline: auto;
}