html { font-size: 16px; } body { margin: 0; font-family: 'Source Sans Pro', Helvetica, sans-serif; line-height: 1.4em; color: #111; background-color: #111; } h1, h2 { font-weight: normal; } h1 { font-size: 2em; } h2 { font-size: 1.25em; } hr { border: 1px solid #111; } .card { padding: 2em; margin: 1em; width: 25em; background-color: #ee0; } @media screen and (max-width: 35em) { .card { width: auto; } }