:root { color-scheme: dark; font-family: system-ui, sans-serif; color: #eff5f8; background: #101a22; }
body { margin: 0 auto; max-width: 55rem; padding: 2rem 1.25rem; line-height: 1.6; }
header { margin-bottom: 4rem; font-weight: 700; font-size: 1.3rem; }
a { color: #8cd8ff; text-underline-offset: .2em; }
button { font: inherit; border: 1px solid #8cd8ff; border-radius: .4rem; background: #174760; color: #fff; padding: .65rem 1.25rem; cursor: pointer; }
nav { margin-top: 3rem; }
:focus-visible { outline: 3px solid #fff; outline-offset: 4px; }