:root {
  --bg: #090c11;
  --bg-soft: #0f141c;
  --panel: #131a23;
  --panel-2: #18212d;
  --text: #f3f6fa;
  --muted: #a7b0bd;
  --subtle: #6f7a88;
  --line: rgba(255, 255, 255, 0.12);
  --line-strong: rgba(255, 255, 255, 0.22);
  --accent: #dfe7ef;
  --accent-dark: #111720;
  --focus: #8fd8ff;
  --shadow: 0 24px 80px rgba(0, 0, 0, 0.34);
  --radius: 20px;
  --shell: min(1180px, calc(100% - 40px));
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
  background: var(--bg);
}

body {
  margin: 0;
  color: var(--text);
  background:
    radial-gradient(circle at 85% 8%, rgba(122, 143, 165, 0.12), transparent 26rem),
    linear-gradient(180deg, #090c11 0%, #0b0f15 100%);
  font-family: Inter, ui-sans-serif, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  font-size: 16px;
  line-height: 1.6;
  text-rendering: optimizeLegibility;
}

a {
  color: inherit;
  text-decoration-thickness: 1px;
  text-underline-offset: 0.2em;
}

button,
a {
  -webkit-tap-highlight-color: transparent;
}

:focus-visible {
  outline: 3px solid var(--focus);
  outline-offset: 4px;
  border-radius: 6px;
}

::selection {
  color: #081016;
  background: #bce9ff;
}

h1,
h2,
h3,
p {
  margin-top: 0;
}

h1,
h2,
h3 {
  line-height: 1.08;
  letter-spacing: -0.035em;
}

h1 {
  max-width: 9ch;
  margin-bottom: 0.15em;
  font-size: clamp(4rem, 11vw, 8.7rem);
  font-weight: 760;
}

h2 {
  max-width: 15ch;
  margin-bottom: 0.7em;
  font-size: clamp(2.35rem, 5.6vw, 4.7rem);
  font-weight: 720;
}

h3 {
  margin-bottom: 0.55em;
  font-size: 1.18rem;
}

p {
  color: var(--muted);
}

.shell {
  width: var(--shell);
  margin-inline: auto;
}

.section {
  position: relative;
  padding: 112px 0;
}

section[id] {
  scroll-margin-top: 88px;
}

.section-muted {
  background: rgba(255, 255, 255, 0.025);
  border-top: 1px solid var(--line);
  border-bottom: 1px solid var(--line);
}

.section-dark {
  background: #070a0f;
  border-top: 1px solid var(--line);
  border-bottom: 1px solid var(--line);
}

.eyebrow {
  margin-bottom: 1rem;
  color: #d8e0e8;
  font-size: 0.76rem;
  font-weight: 760;
  letter-spacing: 0.16em;
  text-transform: uppercase;
}

.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border: 0;
}

.skip-link {
  position: fixed;
  z-index: 1000;
  top: 12px;
  left: 12px;
  padding: 10px 14px;
  color: #081016;
  background: var(--focus);
  transform: translateY(-160%);
  transition: transform 160ms ease;
}

.skip-link:focus {
  transform: translateY(0);
}

.site-header {
  position: fixed;
  z-index: 100;
  top: 0;
  right: 0;
  left: 0;
  border-bottom: 1px solid transparent;
  transition: background 180ms ease, border-color 180ms ease, backdrop-filter 180ms ease;
}

.site-header.is-scrolled {
  background: rgba(9, 12, 17, 0.82);
  border-color: var(--line);
  backdrop-filter: blur(18px);
}

.nav-wrap {
  display: flex;
  min-height: 72px;
  align-items: center;
  justify-content: space-between;
  gap: 24px;
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  color: var(--text);
  font-weight: 720;
  letter-spacing: -0.02em;
  text-decoration: none;
}

.brand-logo {
  display: block;
  width: 30px;
  height: 30px;
  object-fit: contain;
}

.brand-mark {
  width: 22px;
  height: 22px;
  border: 1px solid rgba(255, 255, 255, 0.35);
  border-radius: 50%;
  background:
    radial-gradient(circle at 35% 30%, #f4f7fa 0 7%, transparent 8%),
    radial-gradient(circle at 35% 35%, #9daab7 0 18%, #303b48 42%, #0d1219 75%);
  box-shadow: inset -3px -5px 9px rgba(0, 0, 0, 0.55), 0 0 20px rgba(190, 211, 226, 0.12);
}

.site-nav {
  display: flex;
  align-items: center;
  gap: 26px;
}

.site-nav a {
  color: #c9d1da;
  font-size: 0.9rem;
  font-weight: 630;
  text-decoration: none;
}

.site-nav a:hover {
  color: #fff;
}

.site-nav .nav-cta {
  padding: 9px 14px;
  color: #091016;
  background: #f1f5f8;
  border-radius: 999px;
}

.nav-toggle {
  display: none;
  width: 42px;
  height: 42px;
  padding: 10px;
  border: 1px solid var(--line);
  color: #fff;
  background: transparent;
  border-radius: 10px;
}

.nav-toggle span[aria-hidden="true"] {
  display: block;
  width: 100%;
  height: 1px;
  margin: 6px 0;
  background: currentColor;
}

.hero {
  min-height: 100svh;
  display: grid;
  align-items: center;
  padding-top: 150px;
  overflow: hidden;
}

.hero-noise {
  position: absolute;
  inset: 0;
  pointer-events: none;
  opacity: 0.22;
  background-image: url("data:image/svg+xml,%3Csvg viewBox='0 0 180 180' xmlns='http://www.w3.org/2000/svg'%3E%3Cfilter id='n'%3E%3CfeTurbulence type='fractalNoise' baseFrequency='.9' numOctaves='3' stitchTiles='stitch'/%3E%3C/filter%3E%3Crect width='100%25' height='100%25' filter='url(%23n)' opacity='.10'/%3E%3C/svg%3E");
}

.hero-grid {
  display: grid;
  align-items: center;
  grid-template-columns: minmax(0, 1.15fr) minmax(360px, 0.85fr);
  gap: 6vw;
}

.hero-copy {
  position: relative;
  z-index: 1;
}

.author-line {
  margin-bottom: 2.25rem;
  color: #8f9aa8;
  font-size: 1rem;
}

.hero-tagline {
  margin-bottom: 0.6rem;
  color: #eff3f7;
  font-size: clamp(1.45rem, 3.1vw, 2.4rem);
  font-weight: 620;
  letter-spacing: -0.035em;
}

.hero-summary {
  max-width: 720px;
  margin-bottom: 2rem;
  font-size: clamp(1.05rem, 1.8vw, 1.32rem);
}

.button-row {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-bottom: 1.5rem;
}

.button {
  display: inline-flex;
  min-height: 48px;
  align-items: center;
  justify-content: center;
  padding: 11px 18px;
  border: 1px solid transparent;
  border-radius: 999px;
  font-weight: 720;
  text-decoration: none;
  transition: transform 160ms ease, border-color 160ms ease, background 160ms ease;
}

.button:hover {
  transform: translateY(-2px);
}

.button-primary {
  color: #0b1118;
  background: #edf2f6;
}

.button-secondary {
  color: #e8edf2;
  background: rgba(255, 255, 255, 0.04);
  border-color: var(--line-strong);
}

.hero-caveat {
  max-width: 650px;
  margin-bottom: 0;
  color: #7f8997;
  font-size: 0.88rem;
}

.marble-stage {
  position: relative;
  min-height: 520px;
  display: grid;
  place-items: center;
  border: 1px solid var(--line);
  border-radius: 36px;
  background:
    linear-gradient(140deg, rgba(255, 255, 255, 0.055), transparent 42%),
    rgba(255, 255, 255, 0.018);
  box-shadow: var(--shadow), inset 0 1px rgba(255, 255, 255, 0.06);
  overflow: hidden;
}

.marble-stage::before,
.marble-stage::after {
  content: "";
  position: absolute;
  border: 1px solid rgba(255, 255, 255, 0.08);
  border-radius: 50%;
}

.marble-stage::before {
  width: 410px;
  height: 410px;
}

.marble-stage::after {
  width: 280px;
  height: 280px;
}

.axis-line {
  position: absolute;
  right: 10%;
  left: 10%;
  top: 50%;
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 1px;
  background: rgba(255, 255, 255, 0.22);
}

.axis-node {
  width: 9px;
  height: 9px;
  border: 2px solid #7f8995;
  border-radius: 50%;
  background: #111721;
}

.axis-label {
  position: absolute;
  top: calc(50% - 34px);
  color: #7f8995;
  font-family: ui-monospace, SFMono-Regular, Menlo, monospace;
  font-size: 0.7rem;
  letter-spacing: 0.08em;
  text-transform: uppercase;
}

.axis-label-a {
  left: 10%;
}

.axis-label-b {
  right: 10%;
}

.marble-orbit {
  position: relative;
  z-index: 2;
  width: 150px;
  height: 150px;
  animation: drift 7s ease-in-out infinite;
}

.marble {
  position: absolute;
  inset: 0;
  border: 1px solid rgba(255, 255, 255, 0.28);
  border-radius: 50%;
  background:
    radial-gradient(circle at 32% 26%, rgba(255, 255, 255, 0.95) 0 3%, transparent 4%),
    radial-gradient(circle at 42% 38%, #8896a5 0 9%, #5c6977 19%, #26303b 46%, #0b0f15 78%);
  box-shadow:
    inset -18px -22px 35px rgba(0, 0, 0, 0.65),
    inset 12px 12px 25px rgba(255, 255, 255, 0.09),
    0 34px 72px rgba(0, 0, 0, 0.5),
    0 0 50px rgba(181, 205, 224, 0.12);
}

.marble::before {
  content: "";
  position: absolute;
  inset: 18% 34% 18% 33%;
  border-left: 1px solid rgba(255, 255, 255, 0.18);
  border-radius: 50%;
  transform: rotate(26deg);
}

.marble-core {
  position: absolute;
  width: 27%;
  height: 27%;
  top: 36%;
  left: 36%;
  border: 1px solid rgba(255, 255, 255, 0.14);
  border-radius: 50%;
  background: rgba(255, 255, 255, 0.025);
}

.stage-caption {
  position: absolute;
  right: 28px;
  bottom: 24px;
  left: 28px;
  margin: 0;
  color: #7c8795;
  font-size: 0.8rem;
  text-align: center;
}

@keyframes drift {
  0%, 100% { transform: translate3d(-54px, -8px, 0) rotate(-6deg); }
  50% { transform: translate3d(54px, 8px, 0) rotate(6deg); }
}

.split-heading,
.classification-layout,
.license-grid,
.contact-grid {
  display: grid;
  grid-template-columns: minmax(0, 0.8fr) minmax(0, 1.2fr);
  gap: 8vw;
}

.split-heading > p {
  max-width: 580px;
  margin-top: 3.2rem;
  font-size: 1.08rem;
}

.concept-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  margin-top: 68px;
  border-top: 1px solid var(--line);
  border-left: 1px solid var(--line);
}

.concept-grid article {
  min-height: 270px;
  padding: 30px 26px;
  border-right: 1px solid var(--line);
  border-bottom: 1px solid var(--line);
}

.concept-grid p {
  margin-bottom: 0;
  font-size: 0.93rem;
}

.concept-index {
  display: block;
  margin-bottom: 70px;
  color: var(--subtle);
  font-family: ui-monospace, SFMono-Regular, Menlo, monospace;
  font-size: 0.72rem;
}

.section-heading {
  margin-bottom: 58px;
}

.flow {
  display: grid;
  grid-template-columns: repeat(5, 1fr);
  padding: 0;
  list-style: none;
}

.flow li {
  position: relative;
  min-height: 240px;
  padding: 27px 24px 24px;
  border-top: 1px solid var(--line-strong);
  border-right: 1px solid var(--line);
  border-bottom: 1px solid var(--line);
}

.flow li:first-child {
  border-left: 1px solid var(--line);
  border-radius: var(--radius) 0 0 var(--radius);
}

.flow li:last-child {
  border-radius: 0 var(--radius) var(--radius) 0;
}

.flow-number {
  display: grid;
  width: 34px;
  height: 34px;
  place-items: center;
  margin-bottom: 64px;
  color: #0c1218;
  background: #dfe6ec;
  border-radius: 50%;
  font-size: 0.78rem;
  font-weight: 800;
}

.flow strong,
.flow small {
  display: block;
}

.flow strong {
  margin-bottom: 0.55rem;
  line-height: 1.25;
}

.flow small {
  color: #7f8997;
  font-size: 0.84rem;
  line-height: 1.45;
}

.classification-intro p:last-child {
  max-width: 500px;
}

.classification-list {
  border-top: 1px solid var(--line);
}

.classification-list article {
  display: grid;
  grid-template-columns: 0.6fr 1.4fr;
  gap: 30px;
  padding: 30px 0;
  border-bottom: 1px solid var(--line);
}

.classification-list article > div {
  display: flex;
  align-items: center;
  gap: 12px;
}

.classification-list h3,
.classification-list p {
  margin: 0;
}

.classification-list h3 {
  font-family: ui-monospace, SFMono-Regular, Menlo, monospace;
  font-size: 0.98rem;
  letter-spacing: 0;
}

.classification-list p {
  font-size: 0.92rem;
}

.status-dot {
  width: 9px;
  height: 9px;
  flex: 0 0 auto;
  border: 1px solid rgba(255, 255, 255, 0.35);
  border-radius: 50%;
  background: #909da9;
  box-shadow: 0 0 16px rgba(216, 228, 238, 0.18);
}

.advisory-note {
  display: flex;
  gap: 16px;
  margin-top: 52px;
  padding: 18px 20px;
  border: 1px solid var(--line);
  border-radius: 14px;
  color: #9fa9b6;
  font-size: 0.9rem;
}

.advisory-note strong {
  flex: 0 0 auto;
  color: #e7edf2;
}

.examples-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 22px;
}

.example-panel {
  padding: 30px;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: linear-gradient(155deg, rgba(255, 255, 255, 0.042), rgba(255, 255, 255, 0.012));
}

.example-panel header {
  display: flex;
  gap: 16px;
  margin-bottom: 28px;
}

.example-panel header h3,
.example-panel header p {
  margin-bottom: 0;
}

.example-panel header p {
  font-size: 0.86rem;
}

.example-letter {
  display: grid;
  width: 42px;
  height: 42px;
  flex: 0 0 auto;
  place-items: center;
  border: 1px solid var(--line-strong);
  border-radius: 50%;
  font-weight: 800;
}

.code-block {
  display: grid;
  gap: 7px;
  margin-bottom: 24px;
  padding: 22px;
  border: 1px solid var(--line);
  border-radius: 14px;
  background: #080b10;
  overflow-x: auto;
}

.code-block code {
  color: #d4dce4;
  font-family: ui-monospace, SFMono-Regular, Menlo, monospace;
  font-size: 0.86rem;
}

.code-block code span {
  color: #7e8a98;
}

.example-panel > p {
  margin-bottom: 0;
  font-size: 0.95rem;
}

.example-panel > p strong {
  color: #eef3f7;
  font-family: ui-monospace, SFMono-Regular, Menlo, monospace;
  font-size: 0.9em;
}

.faq-layout {
  display: grid;
  grid-template-columns: minmax(0, 0.72fr) minmax(0, 1.28fr);
  gap: 8vw;
  align-items: start;
}

.faq-intro {
  position: sticky;
  top: 110px;
}

.faq-intro p:last-child {
  max-width: 500px;
}

.faq-list {
  border-top: 1px solid var(--line);
}

.faq-item {
  border-bottom: 1px solid var(--line);
}

.faq-item summary {
  position: relative;
  display: grid;
  grid-template-columns: 1fr 28px;
  gap: 22px;
  align-items: center;
  padding: 24px 0;
  color: #edf3f7;
  cursor: pointer;
  font-size: 1.02rem;
  font-weight: 700;
  line-height: 1.28;
  list-style: none;
}

.faq-item summary::-webkit-details-marker {
  display: none;
}

.faq-item summary::after {
  content: "+";
  display: grid;
  width: 28px;
  height: 28px;
  place-items: center;
  border: 1px solid var(--line-strong);
  border-radius: 50%;
  color: #dce5ed;
  font-family: ui-monospace, SFMono-Regular, Menlo, monospace;
  font-size: 1rem;
  line-height: 1;
}

.faq-item[open] summary::after {
  content: "-";
}

.faq-item summary:hover {
  color: #fff;
}

.faq-item summary:focus-visible {
  outline-offset: 6px;
}

.faq-item p {
  max-width: 740px;
  margin: -2px 0 26px;
  color: #aab4c0;
  font-size: 0.98rem;
}

.status-panel {
  display: grid;
  grid-template-columns: minmax(0, 0.75fr) minmax(0, 1.25fr);
  gap: 8vw;
  padding: 44px;
  border: 1px solid var(--line);
  border-radius: 28px;
  background: rgba(8, 11, 16, 0.65);
}

.status-panel h2 {
  margin-bottom: 0.35em;
}

.status-list {
  margin: 0;
  padding: 0;
  border-top: 1px solid var(--line);
  list-style: none;
}

.status-list li {
  display: flex;
  justify-content: space-between;
  gap: 30px;
  padding: 14px 0;
  border-bottom: 1px solid var(--line);
  font-size: 0.9rem;
}

.status-list span {
  color: #778290;
}

.status-list strong {
  color: #e7edf2;
  font-weight: 650;
  text-align: right;
}

.license-intro {
  align-self: start;
  position: sticky;
  top: 110px;
}

.license-intro p {
  max-width: 470px;
}

.license-rules {
  display: grid;
  gap: 18px;
}

.license-rules article {
  padding: 28px;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: rgba(255, 255, 255, 0.02);
}

.license-rules ul {
  margin: 0;
  padding-left: 1.25rem;
  color: var(--muted);
}

.license-rules li + li {
  margin-top: 0.7rem;
}

.attribution-line {
  padding: 18px 22px;
  border: 1px dashed var(--line-strong);
  border-radius: 14px;
  color: #dfe6ec;
  font-family: ui-monospace, SFMono-Regular, Menlo, monospace;
  font-size: 0.86rem;
  text-align: center;
}

.contact-section {
  background:
    radial-gradient(circle at 8% 100%, rgba(121, 147, 169, 0.12), transparent 28rem),
    #0d1219;
  border-top: 1px solid var(--line);
}

.contact-grid h2 {
  max-width: 13ch;
}

.contact-actions {
  border-top: 1px solid var(--line);
}

.contact-actions a {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 28px;
  padding: 24px 0;
  border-bottom: 1px solid var(--line);
  text-decoration: none;
}

.contact-actions a:hover span,
.contact-actions a:hover strong {
  color: #fff;
}

.contact-actions span {
  color: #8d98a6;
}

.contact-actions strong {
  color: #dfe6ec;
  font-size: 0.95rem;
}

.site-footer {
  padding: 48px 0;
  background: #07090d;
  border-top: 1px solid var(--line);
}

.footer-grid {
  display: grid;
  grid-template-columns: 1fr auto;
  gap: 28px;
  align-items: start;
}

.footer-brand {
  margin-bottom: 10px;
}

.footer-logo {
  width: 34px;
  height: 34px;
}

.site-footer p {
  margin-bottom: 0;
  font-size: 0.84rem;
}

.footer-links {
  display: flex;
  gap: 22px;
}

.footer-links a {
  color: #b2bcc7;
  font-size: 0.84rem;
}

.copyright {
  grid-column: 1 / -1;
  padding-top: 24px;
  border-top: 1px solid var(--line);
}

@media (max-width: 980px) {
  :root {
    --shell: min(100% - 32px, 820px);
  }

  .section {
    padding: 88px 0;
  }

  .hero {
    min-height: auto;
    padding-top: 130px;
  }

  .hero-grid,
  .split-heading,
  .classification-layout,
  .license-grid,
  .contact-grid,
  .faq-layout,
  .status-panel {
    grid-template-columns: 1fr;
    gap: 54px;
  }

  .marble-stage {
    min-height: 430px;
  }

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

  .flow {
    grid-template-columns: 1fr;
  }

  .flow li,
  .flow li:first-child,
  .flow li:last-child {
    min-height: 0;
    display: grid;
    grid-template-columns: 46px 1fr;
    column-gap: 18px;
    padding: 22px;
    border: 1px solid var(--line);
    border-bottom: 0;
    border-radius: 0;
  }

  .flow li:first-child {
    border-radius: var(--radius) var(--radius) 0 0;
  }

  .flow li:last-child {
    border-bottom: 1px solid var(--line);
    border-radius: 0 0 var(--radius) var(--radius);
  }

  .flow-number {
    grid-row: 1 / 3;
    margin: 0;
  }

  .examples-grid {
    grid-template-columns: 1fr;
  }

  .license-intro {
    position: static;
  }

  .faq-intro {
    position: static;
  }
}

@media (max-width: 760px) {
  .brand-logo {
    width: 28px;
    height: 28px;
  }

  .footer-logo {
    width: 30px;
    height: 30px;
  }

  .site-nav {
    position: absolute;
    top: 64px;
    right: 16px;
    left: 16px;
    display: none;
    align-items: stretch;
    padding: 16px;
    border: 1px solid var(--line);
    border-radius: 16px;
    background: rgba(10, 13, 18, 0.97);
    box-shadow: var(--shadow);
  }

  .site-nav.is-open {
    display: grid;
    gap: 4px;
  }

  .site-nav a {
    padding: 11px 12px;
    border-radius: 10px;
  }

  .site-nav .nav-cta {
    margin-top: 4px;
    text-align: center;
  }

  .nav-toggle {
    display: block;
  }

  h1 {
    font-size: clamp(3.45rem, 18vw, 5.6rem);
  }

  .hero-tagline {
    font-size: 1.5rem;
  }

  .marble-stage {
    min-height: 360px;
    border-radius: 24px;
  }

  .marble-stage::before {
    width: 320px;
    height: 320px;
  }

  .marble-stage::after {
    width: 220px;
    height: 220px;
  }

  .marble-orbit {
    width: 112px;
    height: 112px;
  }

  @keyframes drift {
    0%, 100% { transform: translate3d(-35px, -7px, 0) rotate(-5deg); }
    50% { transform: translate3d(35px, 7px, 0) rotate(5deg); }
  }

  .concept-grid {
    grid-template-columns: 1fr;
  }

  .concept-grid article {
    min-height: auto;
  }

  .concept-index {
    margin-bottom: 34px;
  }

  .classification-list article {
    grid-template-columns: 1fr;
    gap: 12px;
  }

  .advisory-note {
    display: grid;
  }

  .faq-item summary {
    grid-template-columns: 1fr 26px;
    gap: 16px;
    padding: 21px 0;
    font-size: 0.98rem;
  }

  .faq-item summary::after {
    width: 26px;
    height: 26px;
  }

  .faq-item p {
    margin-bottom: 24px;
    font-size: 0.94rem;
  }

  .status-panel {
    padding: 28px 22px;
  }

  .status-list li {
    display: grid;
    gap: 3px;
  }

  .status-list strong {
    text-align: left;
  }

  .contact-actions a {
    display: grid;
    gap: 6px;
  }

  .footer-grid {
    grid-template-columns: 1fr;
  }

  .footer-links {
    display: grid;
    gap: 10px;
  }

  .copyright {
    grid-column: auto;
  }
}

@media (max-width: 460px) {
  :root {
    --shell: calc(100% - 24px);
  }

  .section {
    padding: 72px 0;
  }

  .button-row,
  .button {
    width: 100%;
  }

  .example-panel,
  .license-rules article {
    padding: 22px;
  }
}

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

  *,
  *::before,
  *::after {
    scroll-behavior: auto !important;
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
  }
}