:root{--bg:#eef1f6;--card:#fff;--fg:#1b2333;--muted:#5d6a80;--line:#d8deea;--brand:#0f6cbd;--soft:#e3eefa;color-scheme:light dark}
@media (prefers-color-scheme:dark){:root{--bg:#0f1520;--card:#18202d;--fg:#e6ebf3;--muted:#9aa6ba;--line:#2b3546;--brand:#3b8fdb;--soft:#1c2f47}}
*{box-sizing:border-box}
body{margin:0;background:var(--bg);color:var(--fg);font:16px/1.6 "IBM Plex Sans",system-ui,-apple-system,"Segoe UI",sans-serif}
a{color:var(--brand)}
.bar{max-width:820px;margin:20px auto 0;background:var(--brand);border-radius:14px;padding:14px 20px;display:flex;justify-content:space-between;align-items:center;gap:12px;margin-inline:16px}
@media (min-width:852px){.bar{margin-inline:auto}}
.bar a{color:#fff;text-decoration:none}.bar b{display:block;font-size:18px}.bar small{opacity:.85}
.bar .lang{border:1px solid rgba(255,255,255,.5);border-radius:999px;padding:4px 10px;font-size:13px;font-weight:600}
main{max-width:820px;margin:18px auto;padding:0 16px;display:grid;gap:18px}
article,.cta,.more{background:var(--card);border:1px solid var(--line);border-radius:14px;padding:24px}
h1{font-size:28px;line-height:1.25;margin:0 0 12px;text-wrap:balance}
h2{font-size:19px;margin:24px 0 8px}
.cta{background:var(--soft);border-color:var(--brand)}.cta h2{margin-top:0}
.btn{display:inline-block;background:var(--brand);color:#fff;text-decoration:none;font-weight:600;padding:10px 16px;border-radius:10px}
.note{color:var(--muted);font-size:14px}
.formula{background:var(--soft);border-radius:10px;padding:12px 14px;font-weight:600}
table{border-collapse:collapse;width:100%;font-size:15px;display:block;overflow-x:auto}
th,td{text-align:left;padding:8px;border-bottom:1px solid var(--line);vertical-align:top}
code{background:var(--soft);padding:1px 5px;border-radius:5px}
.more h2{margin-top:0}
footer{text-align:center;color:var(--muted);font-size:13px;padding:8px 16px 32px}