body { margin: auto; font-family: sans-serif; color: black; }
main, article, footer { border: 1px solid; padding: 5px; margin: 5px; }
main { display: block; background: #d2d2d2; border-color: #a6a6a6;
 min-width: 16em; }
a { margin: 0; }
input:invalid { border-color: red; }
strong { color: red; }
article { background: #f6fff0; border-color: #a6a6a6; }
.row1 { display: grid; grid-template-columns: 1fr 0.05fr 1fr; }
.col1 { display: flex; flex-direction: column; justify-content: center; }
button { margin: 0.2em; }
footer { font-size: 0.91em; background: #e6ecf2; border-color: #a6a6a6; }
main p { margin: 1em 0; }
footer p { float: right; margin: 0; }
.center { text-align: center; }