:root {
  --btc-orange: #f7931a;
  --btc-orange-dark: #d67d0c;
  --ink: #1d1d1d;
  --muted: #5a5a5a;
  --line: #e4e4e4;
  --paper: #ffffff;
  --wash: #f7f7f7;
  --footer: #1b1b1b;
  --max: 1080px;
  --font: "Helvetica Neue", Helvetica, Arial, sans-serif;
}

*,
*::before,
*::after {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  color: var(--ink);
  background: var(--paper);
  font-family: var(--font);
  font-size: 17px;
  line-height: 1.65;
}

img {
  max-width: 100%;
  height: auto;
}

a {
  color: var(--btc-orange-dark);
  text-decoration: none;
}

a:hover,
a:focus-visible {
  color: var(--btc-orange);
  text-decoration: underline;
}

code {
  font-family: ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
  font-size: 0.92em;
  background: #f1f1f1;
  padding: 0.1em 0.35em;
  border-radius: 3px;
}

pre {
  overflow-x: auto;
  background: #f1f1f1;
  padding: 1rem 1.1rem;
  border-radius: 3px;
}

pre code {
  padding: 0;
  background: none;
}

.skip-link {
  position: absolute;
  left: -999px;
  top: 0;
  background: var(--ink);
  color: #fff;
  padding: 0.6rem 1rem;
  z-index: 100;
}

.skip-link:focus {
  left: 1rem;
  top: 1rem;
}

.wrap {
  width: min(calc(100% - 2.5rem), var(--max));
  margin: 0 auto;
}

.site-header {
  border-top: 3px solid var(--btc-orange);
  border-bottom: 1px solid var(--line);
  background: var(--paper);
}

.header-bar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  min-height: 76px;
  gap: 1.5rem;
}

.brand {
  display: flex;
  align-items: center;
  gap: 0.7rem;
  color: var(--ink);
  text-decoration: none;
  font-weight: 700;
  letter-spacing: 0.01em;
}

.brand:hover,
.brand:focus-visible {
  color: var(--ink);
  text-decoration: none;
}

.brand img {
  width: 36px;
  height: 36px;
}

.brand-text {
  display: flex;
  flex-direction: column;
  line-height: 1.1;
}

.brand-text strong {
  font-size: 1.15rem;
}

.brand-text span {
  font-size: 0.72rem;
  font-weight: 500;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--muted);
}

.nav-toggle {
  display: none;
  border: 1px solid var(--line);
  background: var(--paper);
  color: var(--ink);
  padding: 0.45rem 0.7rem;
  font: inherit;
  cursor: pointer;
}

.site-nav {
  display: flex;
  align-items: center;
  gap: 0.25rem;
}

.nav-item {
  position: relative;
}

.site-nav a,
.site-nav button {
  display: block;
  padding: 0.7rem 0.8rem;
  color: var(--ink);
  background: none;
  border: 0;
  font: inherit;
  cursor: pointer;
}

.site-nav a:hover,
.site-nav button:hover,
.site-nav a:focus-visible,
.site-nav button:focus-visible,
.site-nav a[aria-current="page"] {
  color: var(--btc-orange-dark);
  text-decoration: none;
}

.dropdown-menu {
  display: none;
  position: absolute;
  top: 100%;
  left: 0;
  min-width: 220px;
  background: var(--paper);
  border: 1px solid var(--line);
  box-shadow: 0 10px 24px rgba(0, 0, 0, 0.08);
  padding: 0.4rem 0;
  z-index: 20;
}

.nav-item:hover .dropdown-menu,
.nav-item:focus-within .dropdown-menu,
.nav-item.is-open .dropdown-menu {
  display: block;
}

.dropdown-menu a {
  padding: 0.55rem 1rem;
}

.hero {
  padding: 5.5rem 0 4.5rem;
}

.hero h1 {
  margin: 0 0 1rem;
  font-size: clamp(2.1rem, 5vw, 3.4rem);
  line-height: 1.15;
  letter-spacing: -0.03em;
  max-width: 18ch;
}

.hero .lede {
  max-width: 40rem;
  font-size: 1.2rem;
  color: var(--muted);
  margin: 0 0 1.8rem;
}

.hero-actions,
.button-row {
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem;
}

.button {
  display: inline-block;
  padding: 0.8rem 1.25rem;
  border-radius: 3px;
  font-weight: 600;
  text-decoration: none;
}

.button:hover,
.button:focus-visible {
  text-decoration: none;
}

.button-primary {
  background: var(--btc-orange);
  color: #fff;
}

.button-primary:hover,
.button-primary:focus-visible {
  background: var(--btc-orange-dark);
  color: #fff;
}

.button-secondary {
  background: var(--ink);
  color: #fff;
}

.button-secondary:hover,
.button-secondary:focus-visible {
  color: #fff;
  opacity: 0.92;
}

.button-ghost {
  border: 1px solid var(--line);
  color: var(--ink);
  background: var(--paper);
}

.button-ghost:hover,
.button-ghost:focus-visible {
  color: var(--ink);
  border-color: var(--ink);
}

.section {
  padding: 4rem 0;
}

.section-wash {
  background: var(--wash);
}

.section h2,
.page-header h1 {
  margin: 0 0 1rem;
  font-size: clamp(1.7rem, 3vw, 2.3rem);
  letter-spacing: -0.02em;
}

.section-intro,
.page-header p {
  max-width: 42rem;
  color: var(--muted);
}

.page-header {
  padding: 3.2rem 0 0.5rem;
}

.page-header .kicker {
  margin: 0 0 0.6rem;
  color: var(--btc-orange-dark);
  font-size: 0.82rem;
  font-weight: 700;
  letter-spacing: 0.08em;
  text-transform: uppercase;
}

.prose {
  max-width: 46rem;
  padding: 0 0 4rem;
}

.prose h2,
.prose h3 {
  margin-top: 2.2rem;
  letter-spacing: -0.02em;
}

.prose p,
.prose li {
  color: #333;
}

.prose ul,
.prose ol {
  padding-left: 1.2rem;
}

.card-grid,
.feature-grid,
.audience-grid {
  display: grid;
  gap: 1.25rem;
}

.audience-grid,
.feature-grid {
  grid-template-columns: repeat(3, 1fr);
}

.card-grid {
  grid-template-columns: repeat(2, 1fr);
}

.card,
.audience-card,
.feature-card {
  background: var(--paper);
  border: 1px solid var(--line);
  padding: 1.5rem 1.4rem 1.4rem;
}

.audience-card h3,
.feature-card h3,
.card h3 {
  margin: 0 0 0.6rem;
  font-size: 1.2rem;
}

.audience-card p,
.feature-card p,
.card p {
  margin: 0 0 1rem;
  color: var(--muted);
}

.icon-mark {
  width: 42px;
  height: 42px;
  margin-bottom: 1rem;
  color: var(--btc-orange);
}

.fact-row {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 1.25rem;
  margin-top: 2.5rem;
}

.fact dt {
  font-size: 0.78rem;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--muted);
  margin-bottom: 0.35rem;
}

.fact dd {
  margin: 0;
  font-weight: 700;
  font-size: 1.15rem;
}

.faq-index {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 0.4rem 1.5rem;
  margin: 0 0 2.5rem;
  padding-left: 1.2rem;
  list-style: disc;
}

.faq-index li {
  margin-left: 0.2rem;
}

.faq-item {
  border-top: 1px solid var(--line);
  padding: 1.5rem 0 0.4rem;
}

.faq-item h2 {
  font-size: 1.25rem;
  margin: 0 0 0.7rem;
}

.callout {
  border-left: 3px solid var(--btc-orange);
  background: #fff8ee;
  padding: 1rem 1.15rem;
  margin: 1.5rem 0;
}

.site-footer {
  background: var(--footer);
  color: #d8d8d8;
  padding: 3.2rem 0 1.6rem;
}

.site-footer p {
  color: #b8b8b8;
  max-width: 22rem;
}

.site-footer a {
  color: #f0f0f0;
}

.footer-grid {
  display: grid;
  grid-template-columns: 1.4fr repeat(3, 1fr);
  gap: 2rem;
}

.footer-brand {
  display: flex;
  align-items: center;
  gap: 0.7rem;
  color: #fff;
  font-weight: 700;
  text-decoration: none;
}

.footer-brand:hover {
  color: #fff;
  text-decoration: none;
}

.footer-brand img {
  width: 28px;
  height: 28px;
}

.site-footer h2 {
  margin: 0 0 0.8rem;
  font-size: 0.95rem;
  color: #fff;
}

.site-footer ul {
  list-style: none;
  margin: 0;
  padding: 0;
}

.site-footer li {
  margin: 0.35rem 0;
}

.footer-note {
  margin-top: 2.4rem;
  padding-top: 1.2rem;
  border-top: 1px solid #333;
  color: #9a9a9a;
  font-size: 0.92rem;
}

@media (max-width: 860px) {
  .nav-toggle {
    display: inline-block;
  }

  .site-nav {
    display: none;
    position: absolute;
    left: 0;
    right: 0;
    top: 76px;
    background: var(--paper);
    border-bottom: 1px solid var(--line);
    flex-direction: column;
    align-items: stretch;
    padding: 0.5rem 1.25rem 1rem;
    z-index: 30;
  }

  .site-nav.is-open {
    display: flex;
  }

  .site-header {
    position: relative;
  }

  .dropdown-menu {
    position: static;
    border: 0;
    box-shadow: none;
    padding: 0 0 0.4rem 0.6rem;
  }

  .audience-grid,
  .feature-grid,
  .card-grid,
  .fact-row,
  .faq-index,
  .footer-grid {
    grid-template-columns: 1fr;
  }

  .hero {
    padding: 3.2rem 0 2.8rem;
  }
}