:root { color-scheme: light; font-family: system-ui, "Microsoft JhengHei", sans-serif; color: #19252c; background: #f1f5f6; }
body { margin: 0; padding: 1.25rem; }
main { max-width: 45rem; margin: 1.5rem auto; padding: clamp(1.25rem, 4vw, 3rem); border: 1px solid #d4dee1; border-radius: .75rem; background: #fff; line-height: 1.7; overflow-wrap: anywhere; }
h1, h2 { line-height: 1.3; color: #21494c; }
h1 { font-size: clamp(1.65rem, 5vw, 2.2rem); margin-top: 0; }
h2 { font-size: 1.45rem; margin-top: 2.25rem; }
li + li { margin-top: .8rem; }
a { color: #17616c; text-underline-offset: .15em; }
a:focus-visible { outline: 2px solid #21494c; outline-offset: .15em; }