:root {
  --ink: #141414;
  --paper: #ffffff;
  --red: #d33127;
  --red-d: #b3271e;
  --muted: #8a8a8a;
  --line: #eae7e1;
  --mono: "SF Mono", "JetBrains Mono", "Roboto Mono", Menlo, Consolas, monospace;
  --max: 1040px;
}

* { box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; scroll-behavior: smooth; }
body {
  margin: 0;
  background: var(--paper);
  color: var(--ink);
  font-family: var(--mono);
  font-size: 15px;
  line-height: 1.65;
  -webkit-font-smoothing: antialiased;
}
a { color: var(--red-d); }
img { max-width: 100%; }

.wrap { max-width: var(--max); margin: 0 auto; padding: 0 24px; }

/* header */
header.site { border-bottom: 1.5px solid var(--ink); position: sticky; top: 0; background: var(--paper); z-index: 50; }
header.site .wrap { display: flex; align-items: center; justify-content: space-between; height: 62px; }
.brand { display: flex; align-items: center; gap: 10px; text-decoration: none; color: var(--ink); }
.brand .mark { width: 28px; height: 28px; display: block; border-radius: 6px; }
.brand b { font-size: 15px; letter-spacing: 0.06em; text-transform: uppercase; }
nav.site a { color: var(--ink); text-decoration: none; margin-left: 22px; font-size: 12px; letter-spacing: 0.1em; text-transform: uppercase; }
nav.site a:hover { color: var(--red); }
nav.site a.cta { background: var(--ink); color: #fff; padding: 8px 14px; border-radius: 3px; }
nav.site a.cta:hover { background: var(--red); }

/* generic headings */
h1 { font-size: clamp(38px, 7vw, 68px); line-height: 1.0; letter-spacing: -0.02em; margin: 0; font-weight: 800; }
h2 { font-size: 13px; letter-spacing: 0.22em; text-transform: uppercase; color: var(--red); margin: 0 0 18px; }
h3 { font-size: 19px; letter-spacing: -0.01em; margin: 0 0 6px; }
p { margin: 0 0 16px; }

.kicker { font-size: 12px; letter-spacing: 0.24em; text-transform: uppercase; color: var(--red); margin-bottom: 20px; }
.lede { font-size: clamp(16px, 2.4vw, 20px); color: #444; line-height: 1.55; }
.muted { color: var(--muted); }

.btn { display: inline-block; text-decoration: none; font-family: var(--mono); font-size: 13px; letter-spacing: 0.14em; text-transform: uppercase; font-weight: 700; padding: 14px 24px; border-radius: 3px; cursor: pointer; }
.btn.solid { background: var(--ink); color: #fff; }
.btn.solid:hover { background: var(--red); }
.btn.ghost { background: transparent; color: var(--ink); border: 1.6px solid var(--ink); }
.btn.ghost:hover { background: #f5f2ec; }

section { padding: 70px 0; border-top: 1px solid var(--line); scroll-margin-top: 84px; }
.section-lead { max-width: 640px; }

/* how-it-works steps */
.steps { display: grid; gap: 20px; grid-template-columns: repeat(3, 1fr); margin-top: 34px; padding: 0; list-style: none; }
.steps li { border: 1.5px solid var(--ink); border-radius: 6px; padding: 22px; position: relative; }
.steps li .n { font-size: 12px; letter-spacing: 0.1em; color: var(--red); font-weight: 700; }
.steps li h3 { margin-top: 8px; }
.steps li p { margin: 0; color: #555; font-size: 14px; }

/* science / formula */
.formula { background: var(--ink); color: #fff; border-radius: 8px; padding: 26px 28px; margin-top: 26px; }
.formula code { display: block; font-family: var(--mono); font-size: clamp(15px, 3.6vw, 21px); color: #ffd9a8; margin: 12px 0 6px; letter-spacing: 0.01em; }
.formula small { color: #bdb6a8; letter-spacing: 0.02em; }

/* footer */
footer.site { border-top: 1.5px solid var(--ink); padding: 30px 0; }
footer.site .wrap { display: flex; flex-wrap: wrap; gap: 8px 22px; align-items: center; font-size: 12px; letter-spacing: 0.08em; text-transform: uppercase; color: var(--muted); }
footer.site a { color: var(--muted); text-decoration: none; }
footer.site a:hover { color: var(--red); }
footer.site .sp { flex: 1; }

/* ---------- doc pages (privacy / disclaimer / support) ---------- */
.doc { padding: 54px 0 90px; max-width: 760px; }
.doc h1 { font-size: clamp(30px, 6vw, 44px); margin-bottom: 6px; }
.doc .updated { color: var(--muted); font-size: 12px; letter-spacing: 0.08em; text-transform: uppercase; margin: 0 0 26px; }
.doc h2 { font-size: 15px; letter-spacing: 0.06em; color: var(--ink); text-transform: none; margin: 34px 0 10px; }
.doc p, .doc li { color: #333; }
.doc ul { padding-left: 20px; }
.doc li { margin-bottom: 8px; }
.doc code { background: #f3f0ea; padding: 1px 6px; border-radius: 3px; font-size: 0.92em; }

@media (max-width: 720px) {
  .steps { grid-template-columns: 1fr; }
  header.site nav.site a:not(.cta) { display: none; }
}