:root,[data-theme="dark"]{
  --bg:#050a18;--text:#f4f6fb;--muted:#8f9bb0;--line:rgba(255,255,255,.09);
  --panel:#0b101c;--nav-bg:rgba(8,12,24,.9);--accent:#5eb8ff;--btn-text:#050a18;
  --brand-grad:linear-gradient(115deg,#7dd3fc 0%,#3a8bff 40%,#3a7bd5 70%,#1e4fd8 100%);
  color-scheme:dark;
}
[data-theme="light"]{
  --bg:#f7f8fc;--text:#0a1128;--muted:#5a6578;--line:rgba(10,17,40,.1);
  --panel:#ffffff;--nav-bg:rgba(255,255,255,.94);--accent:#0284c7;--btn-text:#ffffff;
  color-scheme:light;
}
*{box-sizing:border-box}
html{scroll-behavior:smooth}
body{
  margin:0;font-family:system-ui,-apple-system,"Segoe UI",Roboto,Ubuntu,Cantarell,sans-serif;
  background:var(--bg);color:var(--text);line-height:1.65;
}
a{color:var(--accent);text-decoration:none}
a:hover{text-decoration:underline}
.wrap{width:min(calc(100% - 40px),780px);margin:0 auto;padding:120px 0 80px}
.topbar{
  position:fixed;inset:18px 0 auto;z-index:10;pointer-events:none;
}
.topbar-inner{
  pointer-events:auto;width:min(calc(100% - 32px),780px);margin:auto;height:58px;
  display:flex;align-items:center;justify-content:space-between;gap:12px;
  padding:0 16px;border:1px solid var(--line);border-radius:16px;background:var(--nav-bg);
  backdrop-filter:blur(16px);
}
.brand{font:700 1rem system-ui,sans-serif;color:var(--text);text-decoration:none}
.actions{display:flex;gap:8px;align-items:center}
.chip{
  border:1px solid var(--line);background:transparent;color:var(--muted);
  border-radius:10px;padding:7px 10px;font:700 .72rem system-ui;cursor:pointer;letter-spacing:.06em;
}
.chip.active{background:var(--brand-grad);color:var(--btn-text);border-color:transparent}
h1{font-size:clamp(1.8rem,4vw,2.6rem);letter-spacing:-.03em;line-height:1.15;margin:0 0 12px}
.meta{color:var(--muted);font-size:.9rem;margin-bottom:36px}
h2{font-size:1.15rem;margin:32px 0 10px;letter-spacing:-.02em}
p,li{color:var(--muted);font-size:.95rem}
ul{padding-left:1.2rem}
.card{
  border:1px solid var(--line);border-radius:20px;background:var(--panel);
  padding:28px 26px;margin-top:18px;
}
.note{
  margin-top:28px;padding:14px 16px;border-radius:12px;border:1px solid var(--line);
  font-size:.82rem;color:var(--muted);
}
.lang-block{display:none}
.lang-block.show{display:block}
footer.page-foot{margin-top:48px;padding-top:20px;border-top:1px solid var(--line);font-size:.8rem;color:var(--muted)}
@media(max-width:640px){
  .wrap{padding-top:100px}
  .topbar{inset:10px 0 auto}
}