:root {
  color-scheme: light dark;
  --bg: #f6f6f2;
  --surface: #ffffff;
  --text: #171713;
  --muted: #62625b;
  --line: #d9d9d0;
  --soft: #eeeeE7;
  --accent: #1f5eff;
  --accent-text: #ffffff;
  --code: #141414;
  --code-text: #f5f5f2;
  --max: 1080px;
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font-family: ui-sans-serif, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  line-height: 1.55;
}
a { color: inherit; text-decoration-thickness: 1px; text-underline-offset: 3px; }
.site-header {
  max-width: var(--max);
  margin: 0 auto;
  padding: 22px 24px;
  display: flex;
  justify-content: space-between;
  gap: 20px;
  align-items: center;
}
.brand { font-weight: 750; text-decoration: none; letter-spacing: -0.02em; }
.header-actions { display: flex; align-items: center; gap: 18px; }
.small-link { color: var(--muted); font-size: 14px; }
.language-switcher { display: flex; gap: 2px; padding: 3px; border: 1px solid var(--line); border-radius: 9px; background: var(--surface); font-size: 14px; }
.language-switcher a { padding: 4px 8px; border-radius: 6px; color: var(--muted); text-decoration: none; }
.language-switcher a[aria-current="page"] { background: var(--soft); color: var(--text); font-weight: 700; }
a:focus-visible, button:focus-visible, summary:focus-visible { outline: 3px solid var(--accent); outline-offset: 3px; }
main { max-width: var(--max); margin: 0 auto; padding: 0 24px 80px; }
.hero { padding: 40px 0 64px; max-width: 880px; }
.eyebrow { font-size: 13px; text-transform: uppercase; letter-spacing: .12em; font-weight: 750; color: var(--muted); }
h1 { font-size: clamp(42px, 7vw, 78px); line-height: .98; letter-spacing: -0.055em; margin: 18px 0 24px; max-width: 850px; }
.lead { font-size: clamp(19px, 2.4vw, 25px); line-height: 1.42; color: var(--muted); max-width: 800px; }
.prompt-card { margin-top: 42px; background: var(--surface); border: 1px solid var(--line); border-radius: 18px; padding: 24px; box-shadow: 0 18px 60px rgba(0,0,0,.05); }
.prompt-label { font-size: 13px; font-weight: 750; text-transform: uppercase; letter-spacing: .07em; color: var(--muted); }
.prompt-card p { font-size: 18px; margin: 14px 0 20px; }
button { border: 0; border-radius: 10px; padding: 12px 16px; font: inherit; font-weight: 700; background: var(--accent); color: var(--accent-text); cursor: pointer; }
button:hover { filter: brightness(.94); }
#copy-status { margin-left: 12px; font-size: 14px; color: var(--muted); }
.prompt-card .prompt-hint { margin: 18px 0 0; font-size: 14px; color: var(--muted); }
.section { border-top: 1px solid var(--line); padding: 56px 0; }
.section h2 { font-size: clamp(28px, 4vw, 42px); letter-spacing: -.035em; margin: 0 0 24px; }
.section > p { max-width: 800px; color: var(--muted); font-size: 18px; }
.steps { display: grid; grid-template-columns: repeat(4, 1fr); gap: 14px; }
.steps article { background: var(--surface); border: 1px solid var(--line); padding: 20px; border-radius: 14px; }
.steps strong { display: inline-grid; place-items: center; width: 30px; height: 30px; border-radius: 999px; background: var(--soft); }
.steps h3 { font-size: 18px; margin: 18px 0 8px; }
.steps p { margin: 0; color: var(--muted); font-size: 15px; }
.steps + p { margin-top: 28px; }
.flow { display: flex; gap: 12px; align-items: center; flex-wrap: wrap; margin-top: 28px; }
.flow span { border: 1px solid var(--line); background: var(--surface); border-radius: 999px; padding: 9px 14px; font-weight: 650; font-size: 14px; }
.flow i { color: var(--muted); font-style: normal; }
.requirements { margin-top: 42px; }
.requirements h2 { font-size: 20px; letter-spacing: -.025em; margin: 0 0 16px; }
.requirements-list { list-style: none; margin: 0; padding: 0; display: grid; grid-template-columns: 1fr 1fr; gap: 14px; }
.requirements-list li { background: var(--surface); border: 1px solid var(--line); border-radius: 14px; padding: 22px; color: var(--muted); font-size: 16px; }
.requirements-list strong { display: block; margin-bottom: 8px; color: var(--text); font-size: 18px; }
.protocol-shell { border-top: 1px solid var(--line); margin-top: 20px; }
.protocol-shell > summary { list-style: none; cursor: pointer; padding: 34px 0; display: flex; justify-content: space-between; align-items: baseline; gap: 20px; font-size: 20px; font-weight: 750; }
.protocol-shell > summary::-webkit-details-marker { display: none; }
.protocol-shell > summary::after { content: "+"; font-size: 28px; font-weight: 400; }
.protocol-shell[open] > summary::after { content: "−"; }
.protocol-shell > summary small { display: block; margin-left: auto; margin-right: 18px; color: var(--muted); font-weight: 400; font-size: 14px; }
.protocol { background: var(--surface); border: 1px solid var(--line); border-radius: 18px; overflow: hidden; }
.protocol-header, .protocol section { padding: 32px clamp(22px, 5vw, 54px); }
.protocol section { border-top: 1px solid var(--line); }
.machine-kicker { font-size: 12px; letter-spacing: .12em; font-weight: 800; color: var(--accent); }
.protocol h2 { font-size: clamp(30px, 5vw, 52px); line-height: 1; letter-spacing: -.045em; margin: 12px 0 20px; }
.protocol h3 { font-size: 26px; letter-spacing: -.025em; margin: 0 0 18px; }
.protocol h4 { font-size: 19px; margin: 30px 0 10px; }
.protocol p, .protocol li { max-width: 900px; }
.protocol li + li { margin-top: 7px; }
.protocol pre { background: var(--code); color: var(--code-text); overflow: auto; padding: 16px 18px; border-radius: 10px; font-size: 14px; }
.protocol code { font-family: ui-monospace, SFMono-Regular, Menlo, Consolas, monospace; }
.protocol :not(pre) > code { background: var(--soft); padding: 2px 5px; border-radius: 5px; font-size: .92em; }
.protocol blockquote { margin: 18px 0; padding: 16px 18px; border-left: 4px solid var(--accent); background: var(--soft); border-radius: 0 10px 10px 0; }
.protocol .cloudflare { background: linear-gradient(180deg, rgba(31,94,255,.045), transparent 18%); }
.references a { color: var(--accent); }
.completion-contract { background: var(--soft); }
footer { max-width: var(--max); margin: 0 auto; padding: 24px 24px 54px; color: var(--muted); font-size: 14px; }

@media (prefers-color-scheme: dark) {
  :root {
    --bg: #11110f;
    --surface: #191917;
    --text: #f0f0ea;
    --muted: #a5a59d;
    --line: #33332e;
    --soft: #242420;
    --accent: #7ea2ff;
    --accent-text: #101010;
    --code: #080808;
    --code-text: #f3f3ef;
  }
  .prompt-card { box-shadow: none; }
}

@media (max-width: 800px) {
  .steps { grid-template-columns: 1fr 1fr; }
  .requirements-list { grid-template-columns: 1fr; }
  .hero { padding-top: 28px; }
  .protocol-shell > summary small { display: none; }
}

@media (max-width: 520px) {
  main, .site-header, footer { padding-left: 18px; padding-right: 18px; }
  .site-header { align-items: flex-start; flex-direction: column; gap: 12px; }
  .header-actions { width: 100%; justify-content: space-between; gap: 12px; flex-wrap: wrap; }
  .steps { grid-template-columns: 1fr; }
  .prompt-card { padding: 18px; }
  #copy-status { display: block; margin: 10px 0 0; }
  .prompt-card .prompt-hint { margin-top: 14px; }
}