body { font-family: system-ui, Arial, sans-serif; padding: 24px; }
main { max-width: 840px; margin: auto; }
h1 { margin-bottom: 16px; }
form label { display: block; margin: 8px 0; }
.row { display: grid; grid-template-columns: repeat(4, 1fr); gap: 8px; }
button { padding: 8px 12px; }
.hidden { display: none; }
#output img { max-width: 100%; height: auto; margin-top: 12px; border: 1px solid #ddd; }