:root {
  color-scheme: dark;
  --bg: #000;
  --fg: #fff;
  --muted: rgba(255,255,255,.62);
  --faint: rgba(255,255,255,.34);
  --line: rgba(255,255,255,.18);
  --face: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto,
          "Helvetica Neue", Arial, sans-serif;
}

*, *::before, *::after { box-sizing: border-box; }
html { background: var(--bg); scroll-behavior: smooth; }
body {
  margin: 0;
  background: var(--bg);
  color: var(--fg);
  font-family: var(--face);
  font-weight: 400;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}

a { color: inherit; text-underline-offset: .22em; }
a:hover { text-decoration-thickness: 1px; }
a:focus-visible { outline: 1px solid #fff; outline-offset: .35rem; }

.topbar {
  width: min(100% - 2rem, 76rem);
  margin: 0 auto;
  padding: clamp(1.35rem, 4vw, 2.5rem) 0;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1.5rem;
  font-size: .78rem;
  letter-spacing: .08em;
}

.brand, .lang a { text-decoration: none; }
.brand { color: var(--fg); }
.lang { color: var(--muted); white-space: nowrap; }
.lang [aria-current="page"] { color: var(--fg); }

main {
  width: min(100% - 2rem, 76rem);
  margin: 0 auto;
  padding: clamp(4rem, 12vh, 8rem) 0 clamp(5rem, 12vh, 9rem);
}

.hero { max-width: 68rem; }
.kicker {
  margin: 0 0 clamp(1.2rem, 3vw, 2rem);
  color: var(--muted);
  font-size: .76rem;
  line-height: 1.4;
  letter-spacing: .14em;
  text-transform: uppercase;
}

h1 {
  max-width: 64rem;
  margin: 0;
  font-size: clamp(2.55rem, 7.5vw, 6.9rem);
  line-height: .96;
  letter-spacing: -.055em;
  font-weight: 400;
}

.byline {
  margin: clamp(1.5rem, 4vw, 2.6rem) 0 0;
  color: var(--muted);
  font-size: clamp(.9rem, 1.7vw, 1.05rem);
}

.claim {
  max-width: 54rem;
  margin: clamp(4.5rem, 12vw, 9rem) 0 0;
  padding: 0 0 0 clamp(1rem, 2.8vw, 2rem);
  border-left: 1px solid var(--fg);
  font-size: clamp(1.35rem, 3.2vw, 2.45rem);
  line-height: 1.17;
  letter-spacing: -.025em;
}

.actions {
  display: flex;
  flex-wrap: wrap;
  gap: .7rem;
  margin-top: clamp(2.2rem, 5vw, 3.5rem);
}

.button {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 3rem;
  padding: .78rem 1rem;
  border: 1px solid var(--fg);
  text-decoration: none;
  font-size: .82rem;
  letter-spacing: .045em;
}
.button.primary { background: var(--fg); color: var(--bg); }
.button:hover { background: var(--fg); color: var(--bg); }
.button.primary:hover { background: var(--bg); color: var(--fg); }

.content {
  max-width: 64rem;
  margin-top: clamp(6rem, 15vw, 11rem);
}

section {
  display: grid;
  grid-template-columns: minmax(9rem, 14rem) minmax(0, 43rem);
  gap: clamp(1.5rem, 5vw, 4.5rem);
  padding: clamp(2.3rem, 6vw, 4.5rem) 0;
  border-top: 1px solid var(--line);
}

h2 {
  margin: 0;
  font-size: .75rem;
  line-height: 1.45;
  letter-spacing: .13em;
  text-transform: uppercase;
  font-weight: 500;
}

.prose { min-width: 0; }
.prose > :first-child { margin-top: 0; }
.prose > :last-child { margin-bottom: 0; }
.prose p, .prose li {
  font-size: clamp(1rem, 1.65vw, 1.13rem);
  line-height: 1.62;
}
.prose p { margin: 0 0 1.2em; }
.prose ul { margin: 0; padding-left: 1.15em; }
.prose li + li { margin-top: .65em; }

.method {
  margin: 0;
  display: grid;
  gap: 1.7rem;
}
.method > div { padding-bottom: 1.7rem; border-bottom: 1px solid var(--line); }
.method > div:last-child { padding-bottom: 0; border-bottom: 0; }
.method dt {
  margin: 0 0 .55rem;
  font-size: .76rem;
  letter-spacing: .08em;
  text-transform: uppercase;
  color: var(--muted);
}
.method dd {
  margin: 0;
  font-size: clamp(1rem, 1.65vw, 1.13rem);
  line-height: 1.58;
}

.formula {
  overflow-x: auto;
  padding: 1.2rem 0;
  color: var(--fg);
  font: 400 clamp(.95rem, 2vw, 1.2rem)/1.55 ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
  white-space: nowrap;
}

.files { display: grid; gap: .8rem; }
.file {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: 1rem;
  padding: 1rem 0;
  border-bottom: 1px solid var(--line);
  text-decoration: none;
}
.file:first-child { border-top: 1px solid var(--line); }
.file span:last-child { color: var(--muted); font-size: .78rem; letter-spacing: .08em; }
.file:hover span:first-child { text-decoration: underline; text-underline-offset: .25em; }

.citation {
  padding: 1rem;
  border: 1px solid var(--line);
  color: var(--muted);
  font: 400 .84rem/1.55 ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
  overflow-wrap: anywhere;
}

footer {
  width: min(100% - 2rem, 76rem);
  margin: 0 auto;
  padding: 2rem 0 3rem;
  border-top: 1px solid var(--line);
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 1rem;
  color: var(--muted);
  font-size: .74rem;
  letter-spacing: .08em;
}
.mark { width: 17px; height: auto; color: #fff; }

@media (max-width: 720px) {
  main { padding-top: 3.5rem; }
  section { grid-template-columns: 1fr; gap: 1.2rem; }
  h1 { font-size: clamp(2.55rem, 13vw, 4.3rem); }
  .claim { font-size: clamp(1.35rem, 6.4vw, 2rem); }
  .file { align-items: center; }
}

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
}