/* Pebble Dynamics — apple.com-style spacing & scale */

:root {
  --bg: #ffffff;
  --bg-dark: #000000;
  --fg: #1d1d1f;
  --fg-dark: #f5f5f7;
  --muted: #6e6e73;
  --muted-dark: #86868b;
  --accent: #0071e3;
  --accent-hover: #0077ed;
  --line: rgba(0,0,0,0.1);
  --line-dark: rgba(255,255,255,0.12);

  --max: 980px;
  --max-narrow: 720px;

  --font: -apple-system, BlinkMacSystemFont, "SF Pro Display", "SF Pro Text", "Helvetica Neue", Helvetica, Arial, sans-serif;
}

* { box-sizing: border-box; }
html { -webkit-font-smoothing: antialiased; -moz-osx-font-smoothing: grayscale; }
body {
  margin: 0;
  font-family: var(--font);
  font-size: 17px;
  line-height: 1.47;
  color: var(--fg);
  background: var(--bg);
  letter-spacing: -0.01em;
}

a { color: inherit; text-decoration: none; }

/* ---- Nav ---- */
.nav {
  position: sticky;
  top: 0;
  z-index: 100;
  background: rgba(255,255,255,0.72);
  backdrop-filter: saturate(180%) blur(20px);
  -webkit-backdrop-filter: saturate(180%) blur(20px);
  border-bottom: 1px solid var(--line);
}
.nav-inner {
  max-width: 1024px;
  margin: 0 auto;
  padding: 0 22px;
  height: 48px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  font-size: 14px;
}
.brand { font-weight: 600; letter-spacing: -0.015em; }
.nav nav a {
  color: var(--fg);
  opacity: 0.85;
  margin-left: 28px;
  transition: opacity .2s;
}
.nav nav a:hover { opacity: 1; }

/* ---- Layout ---- */
.container {
  max-width: var(--max);
  margin: 0 auto;
  padding: 0 22px;
}
.container.narrow { max-width: var(--max-narrow); }
.center { text-align: center; }

/* ---- Type ---- */
h1, h2, h3 { margin: 0; font-weight: 600; letter-spacing: -0.04em; }
h1 {
  font-size: clamp(48px, 7.5vw, 96px);
  line-height: 1.04;
  letter-spacing: -0.045em;
}
h2 {
  font-size: clamp(36px, 4.4vw, 56px);
  line-height: 1.08;
  letter-spacing: -0.035em;
}
h3 {
  font-size: 24px;
  line-height: 1.2;
  letter-spacing: -0.02em;
}

p { margin: 0; }
.eyebrow {
  font-size: 13px;
  font-weight: 600;
  letter-spacing: 0.02em;
  text-transform: none;
  color: var(--muted);
  margin-bottom: 18px;
}
.lede {
  font-size: clamp(20px, 2vw, 24px);
  line-height: 1.4;
  color: var(--fg);
  max-width: 720px;
  margin-top: 28px;
  letter-spacing: -0.015em;
}
.body {
  font-size: 19px;
  line-height: 1.5;
  color: var(--fg);
  max-width: 720px;
  margin-top: 28px;
  letter-spacing: -0.012em;
}
.footnote {
  font-size: 13px;
  color: var(--muted-dark);
  margin-top: 56px;
  font-family: ui-monospace, SFMono-Regular, "SF Mono", Menlo, monospace;
  letter-spacing: 0.02em;
}

/* ---- Buttons ---- */
.cta-row { margin-top: 48px; display: flex; gap: 24px; flex-wrap: wrap; }
.btn {
  display: inline-block;
  font-size: 17px;
  line-height: 1;
  padding: 14px 24px;
  border-radius: 980px;
  transition: background .2s, color .2s, transform .15s;
  white-space: nowrap;
}
.btn.primary { background: var(--accent); color: #fff; }
.btn.primary:hover { background: var(--accent-hover); }
.btn.ghost { color: var(--accent); }
.btn.ghost:hover { color: var(--accent-hover); }
.btn.large { padding: 18px 32px; font-size: 19px; }

/* ---- Hero ---- */
.hero {
  padding: 140px 0 160px;
  text-align: left;
}

/* ---- Sections ---- */
.section {
  padding: 140px 0;
  border-top: 1px solid var(--line);
}
.section.dark {
  background: var(--bg-dark);
  color: var(--fg-dark);
  border-top-color: transparent;
}
.section.dark .body,
.section.dark h2,
.section.dark h3 { color: var(--fg-dark); }
.section.dark .eyebrow { color: var(--muted-dark); }

/* ---- Stats ---- */
.stats {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 32px;
  margin-top: 96px;
}
.stat .num {
  font-size: clamp(40px, 5vw, 64px);
  font-weight: 600;
  letter-spacing: -0.04em;
  line-height: 1;
}
.stat .label {
  margin-top: 12px;
  font-size: 15px;
  color: var(--muted);
}

/* ---- Layers list ---- */
.layers {
  list-style: none;
  padding: 0;
  margin: 96px 0 0;
  counter-reset: layer;
  display: grid;
  gap: 1px;
  background: var(--line-dark);
  border-top: 1px solid var(--line-dark);
  border-bottom: 1px solid var(--line-dark);
}
.layers li {
  background: var(--bg-dark);
  padding: 40px 0;
  display: grid;
  grid-template-columns: 240px 1fr;
  gap: 48px;
  counter-increment: layer;
}
.layers li::before {
  content: "0" counter(layer);
  font-family: ui-monospace, SFMono-Regular, monospace;
  font-size: 13px;
  color: var(--muted-dark);
  align-self: start;
}
.layer-name {
  font-size: 22px;
  font-weight: 600;
  letter-spacing: -0.02em;
}
.layer-body {
  font-size: 17px;
  line-height: 1.5;
  color: var(--muted-dark);
  max-width: 540px;
}

/* ---- Process ---- */
.process {
  list-style: none;
  padding: 0;
  margin: 96px 0 0;
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 48px 64px;
}
.process li {
  position: relative;
  padding-top: 16px;
  border-top: 1px solid var(--line);
}
.process .step {
  font-family: ui-monospace, SFMono-Regular, monospace;
  font-size: 13px;
  color: var(--muted);
  letter-spacing: 0.04em;
}
.process h3 { margin-top: 16px; }
.process p {
  margin-top: 14px;
  font-size: 17px;
  line-height: 1.5;
  color: var(--muted);
}

/* ---- Contact ---- */
.contact .body { margin-left: auto; margin-right: auto; }
.contact .btn { margin-top: 32px; }
.contact-form {
  display: grid;
  gap: 20px;
  margin: 48px auto 0;
  max-width: 520px;
  text-align: left;
}
.contact-form label { display: grid; gap: 8px; font-size: 13px; color: var(--muted); }
.contact-form input,
.contact-form textarea {
  font: inherit;
  padding: 12px 14px;
  border-radius: 8px;
  border: 1px solid rgba(255,255,255,0.18);
  background: rgba(255,255,255,0.04);
  color: inherit;
  width: 100%;
  box-sizing: border-box;
}
.contact-form input:focus,
.contact-form textarea:focus {
  outline: none;
  border-color: var(--accent);
}
.contact-form button { justify-self: center; margin-top: 8px; }

/* ---- Footer ---- */
footer {
  padding: 32px 0 48px;
  background: #f5f5f7;
  font-size: 12px;
  color: var(--muted);
}
.footer-inner { display: flex; flex-direction: column; gap: 6px; }
.footer-inner .muted { opacity: 0.85; }

/* ---- Responsive ---- */
@media (max-width: 768px) {
  .hero { padding: 96px 0 112px; }
  .section { padding: 96px 0; }
  .stats { grid-template-columns: repeat(2, 1fr); gap: 40px 24px; }
  .layers li { grid-template-columns: 1fr; gap: 8px; padding: 32px 0; }
  .layers li::before { font-size: 12px; }
  .process { grid-template-columns: 1fr; gap: 40px; }
  .nav nav a { margin-left: 18px; font-size: 13px; }
  .lede, .body { font-size: 17px; }
}