html { font-family: system-ui, sans-serif; background: #f4f5f7; color: #1d2939; }
main { max-width: 40rem; margin: 5vh auto; padding: 2rem; background: white; border-radius: 1rem; }
p { line-height: 1.65; }
button { font: inherit; cursor: pointer; padding: .9rem 1rem; border: 0; border-radius: .5rem; background: #253e35; color: white; }
button:disabled { opacity: .65; cursor: default; }