:root{--bg:#ffffff;--fg:#0f172a;--accent:#2563eb;--muted:#64748b}*{box-sizing:border-box;padding:0;margin:0}body,html{max-width:100vw;font-family:system-ui,-apple-system,Segoe UI,Roboto,PingFang SC,Microsoft YaHei,sans-serif;background:var(--bg);color:var(--fg)}a{color:inherit;text-decoration:none}@keyframes learnPulse{0%,to{opacity:.55}50%{opacity:1}}html{-webkit-tap-highlight-color:transparent}