:root {
  --bg: #f6f7f8;
  --surface: #ffffff;
  --text: #111418;
  --muted: #646b74;
  --faint: #8a9199;
  --line: #d9dde2;
  --line-strong: #b8bec6;
  --accent: #215ee7;
  --accent-soft: #e8efff;
  --max-width: 1180px;
  --rail-width: 172px;
  --gutter: clamp(20px, 4vw, 56px);
  --sans: ui-sans-serif, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  --mono: "SFMono-Regular", Consolas, "Liberation Mono", Menlo, monospace;
}

* {
  box-sizing: border-box;
}

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

body {
  margin: 0;
  color: var(--text);
  background:
    linear-gradient(
      to right,
      transparent calc(50% - 0.5px),
      rgba(17, 20, 24, 0.025) 50%,
      transparent calc(50% + 0.5px)
    ),
    var(--bg);
  font-family: var(--sans);
  font-size: 16px;
  line-height: 1.6;
  text-rendering: optimizeLegibility;
  -webkit-font-smoothing: antialiased;
}

::selection {
  color: var(--text);
  background: var(--accent-soft);
}

a {
  color: inherit;
  text-decoration-color: var(--line-strong);
  text-underline-offset: 0.22em;
  text-decoration-thickness: 1px;
}

a:hover {
  color: var(--accent);
  text-decoration-color: currentColor;
}

a:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 4px;
  border-radius: 2px;
}

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

h1,
h2,
h3 {
  line-height: 1.06;
  letter-spacing: -0.035em;
  text-wrap: balance;
}

h1 {
  max-width: 920px;
  margin-bottom: 30px;
  font-size: clamp(3rem, 7vw, 6.8rem);
  font-weight: 590;
}

h2 {
  margin-bottom: 24px;
  font-size: clamp(2.15rem, 4.5vw, 4.35rem);
  font-weight: 580;
}

h3 {
  margin-bottom: 10px;
  font-size: 1.15rem;
  font-weight: 650;
  letter-spacing: -0.02em;
}

.shell {
  width: min(calc(100% - (var(--gutter) * 2)), var(--max-width));
  margin-inline: auto;
}

.skip-link {
  position: fixed;
  top: 12px;
  left: 12px;
  z-index: 100;
  padding: 10px 14px;
  color: #fff;
  background: var(--text);
  transform: translateY(-150%);
}

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

.site-header {
  position: sticky;
  top: 0;
  z-index: 20;
  border-bottom: 1px solid rgba(184, 190, 198, 0.72);
  background: rgba(246, 247, 248, 0.9);
  backdrop-filter: blur(12px);
}

.header-grid,
.footer-grid {
  display: grid;
  grid-template-columns: var(--rail-width) minmax(0, 1fr);
  align-items: center;
  min-height: 64px;
}

.brand {
  width: max-content;
  font-family: var(--mono);
  font-size: 0.86rem;
  font-weight: 650;
  text-decoration: none;
}

.nav {
  display: flex;
  justify-content: flex-end;
  gap: clamp(18px, 3vw, 36px);
  font-family: var(--mono);
  font-size: 0.76rem;
  text-transform: uppercase;
  letter-spacing: 0.04em;
}

.nav a {
  color: var(--muted);
  text-decoration: none;
}

.nav a:hover {
  color: var(--text);
}

.hero,
.section {
  scroll-margin-block-start: 64px;
  display: grid;
  grid-template-columns: var(--rail-width) minmax(0, 1fr);
  border-bottom: 1px solid var(--line);
}

.hero {
  min-height: min(840px, calc(100vh - 64px));
}

.section-rail {
  display: flex;
  flex-direction: column;
  gap: 8px;
  padding: 38px 24px 38px 0;
  border-right: 1px solid var(--line);
  font-family: var(--mono);
  font-size: 0.72rem;
  text-transform: uppercase;
  letter-spacing: 0.055em;
}

.section-index {
  color: var(--accent);
  font-weight: 700;
}

.section-label {
  color: var(--faint);
}

.hero-content,
.section-content {
  padding-left: clamp(28px, 5vw, 70px);
}

.hero-content {
  display: flex;
  min-height: inherit;
  flex-direction: column;
  justify-content: center;
  padding-top: 84px;
  padding-bottom: 72px;
}

.section-content {
  padding-top: clamp(80px, 10vw, 140px);
  padding-bottom: clamp(80px, 10vw, 140px);
}

.eyebrow,
.block-label {
  font-family: var(--mono);
  text-transform: uppercase;
  letter-spacing: 0.055em;
}

.eyebrow {
  margin-bottom: 26px;
  color: var(--accent);
  font-size: 0.74rem;
  font-weight: 700;
}

.block-label {
  margin-bottom: 18px;
  color: var(--faint);
  font-size: 0.7rem;
  font-weight: 650;
}

.hero-copy,
.lede,
.experience-summary {
  max-width: 760px;
  color: #3e454d;
  font-size: clamp(1.08rem, 1.8vw, 1.34rem);
  line-height: 1.55;
}

.hero-copy {
  margin-bottom: 36px;
}

.hero-actions,
.contact-links {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 22px;
}

.hero-actions {
  margin-bottom: 78px;
}

.primary-link {
  display: inline-flex;
  align-items: center;
  min-height: 44px;
  padding: 0 18px;
  color: #fff;
  background: var(--text);
  font-family: var(--mono);
  font-size: 0.78rem;
  font-weight: 650;
  text-decoration: none;
  text-transform: uppercase;
  letter-spacing: 0.04em;
}

.primary-link::after {
  margin-left: 12px;
  content: "↗";
}

.primary-link:hover {
  color: #fff;
  background: var(--accent);
}

.hero-meta {
  display: grid;
  max-width: 760px;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  margin-bottom: 0;
  border-top: 1px solid var(--line);
}

.hero-meta div {
  padding: 16px 16px 0 0;
}

.hero-meta dt {
  margin-bottom: 5px;
  color: var(--faint);
  font-family: var(--mono);
  font-size: 0.67rem;
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

.hero-meta dd {
  margin-left: 0;
  font-size: 0.92rem;
}

.section-heading {
  max-width: 900px;
  margin-bottom: 72px;
}

.compact-heading {
  margin-bottom: 56px;
}

.project-grid,
.feature-layout {
  display: grid;
  grid-template-columns: minmax(0, 1.2fr) minmax(280px, 0.8fr);
  gap: clamp(38px, 7vw, 84px);
  margin-bottom: 72px;
}

.project-block p:not(.block-label),
.feature-copy p {
  color: #3e454d;
  font-size: 1.03rem;
}

.project-block p:last-child,
.feature-copy p:last-child {
  margin-bottom: 0;
}

.system-map {
  padding-top: 4px;
}

.system-map ol {
  margin: 0;
  padding: 0;
  list-style: none;
  counter-reset: system;
}

.system-map li {
  position: relative;
  display: grid;
  grid-template-columns: 24px 1fr;
  align-items: center;
  min-height: 48px;
  counter-increment: system;
  color: #343a42;
  font-family: var(--mono);
  font-size: 0.78rem;
}

.system-map li::before {
  color: var(--accent);
  content: counter(system, decimal-leading-zero);
}

.system-map li:not(:last-child)::after {
  position: absolute;
  bottom: -6px;
  left: 7px;
  width: 1px;
  height: 12px;
  background: var(--line-strong);
  content: "";
}

.system-map li span {
  display: block;
  padding: 12px 0 12px 16px;
  border-bottom: 1px solid var(--line);
}

.decision-list,
.principles {
  border-top: 1px solid var(--line-strong);
}

.decision,
.principles article {
  display: grid;
  grid-template-columns: 72px minmax(0, 1fr);
  gap: 20px;
  padding: 28px 0;
  border-bottom: 1px solid var(--line);
}

.decision-number,
.principles article > span {
  color: var(--accent);
  font-family: var(--mono);
  font-size: 0.76rem;
  font-weight: 700;
}

.decision p,
.principles p {
  max-width: 760px;
  margin-bottom: 0;
  color: var(--muted);
}

.impact {
  display: grid;
  grid-template-columns: 160px minmax(0, 1fr);
  gap: 24px;
  margin-top: 64px;
  padding: 30px 0 0;
  border-top: 1px solid var(--line-strong);
}

.impact p:last-child {
  max-width: 740px;
  margin-bottom: 0;
  font-size: 1.08rem;
}

.config-tree {
  padding: 22px;
  border: 1px solid var(--line);
  background: rgba(255, 255, 255, 0.55);
}

.config-tree pre {
  margin-bottom: 0;
  overflow-x: auto;
  color: #2f353c;
  font-family: var(--mono);
  font-size: 0.78rem;
  line-height: 1.75;
}

.progression {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  margin: 72px 0 0;
  padding: 0;
  border-top: 1px solid var(--line-strong);
  list-style: none;
}

.progression li {
  min-height: 210px;
  padding: 22px 22px 0 0;
  border-right: 1px solid var(--line);
}

.progression li + li {
  padding-left: 22px;
}

.progression li:last-child {
  border-right: 0;
}

.progression-year {
  display: block;
  margin-bottom: 48px;
  color: var(--accent);
  font-family: var(--mono);
  font-size: 0.72rem;
  font-weight: 700;
}

.progression strong {
  display: block;
  margin-bottom: 10px;
  font-size: 0.97rem;
}

.progression p {
  margin-bottom: 0;
  color: var(--muted);
  font-size: 0.88rem;
}

.principles article {
  grid-template-columns: 72px minmax(0, 1fr);
  padding-block: 34px;
}

.principles h3 {
  font-size: clamp(1.25rem, 2vw, 1.65rem);
}

.experience-header {
  display: flex;
  align-items: flex-start;
  justify-content: space-between;
  gap: 32px;
  padding-bottom: 30px;
  border-bottom: 1px solid var(--line-strong);
}

.experience-header h2 {
  margin-bottom: 0;
}

.role-title {
  margin: 8px 0 0;
  color: var(--muted);
  font-family: var(--mono);
  font-size: 0.78rem;
  text-transform: uppercase;
  letter-spacing: 0.045em;
}

.experience-summary {
  margin: 40px 0 64px;
}

.timeline {
  position: relative;
}

.timeline::before {
  position: absolute;
  top: 10px;
  bottom: 10px;
  left: 67px;
  width: 1px;
  background: var(--line);
  content: "";
}

.timeline-item {
  position: relative;
  display: grid;
  grid-template-columns: 68px minmax(0, 1fr);
  gap: 34px;
  padding-bottom: 34px;
}

.timeline-item:last-child {
  padding-bottom: 0;
}

.timeline-date {
  position: relative;
  z-index: 1;
  width: max-content;
  padding-right: 8px;
  color: var(--accent);
  background: var(--bg);
  font-family: var(--mono);
  font-size: 0.7rem;
  font-weight: 700;
  text-transform: uppercase;
}

.timeline-item strong {
  display: block;
  margin-bottom: 5px;
}

.timeline-item p {
  margin-bottom: 0;
  color: var(--muted);
}

.toolkit > h2 {
  max-width: 720px;
}

.toolkit-groups {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 54px;
  margin-top: 60px;
  padding-top: 30px;
  border-top: 1px solid var(--line-strong);
}

.tool-list {
  max-width: 520px;
  margin-bottom: 0;
  font-size: 1.02rem;
  line-height: 1.9;
}

.contact-section {
  border-bottom: 0;
}

.contact-content {
  padding-top: clamp(100px, 13vw, 180px);
  padding-bottom: clamp(110px, 14vw, 200px);
}

.contact-content h2 {
  max-width: 780px;
}

.contact-email {
  display: inline-block;
  margin: 52px 0 26px;
  font-size: clamp(1.25rem, 3vw, 2.4rem);
  font-weight: 560;
  letter-spacing: -0.025em;
  overflow-wrap: anywhere;
}

.contact-links {
  font-family: var(--mono);
  font-size: 0.78rem;
  text-transform: uppercase;
  letter-spacing: 0.04em;
}

.site-footer {
  border-top: 1px solid var(--line-strong);
}

.footer-grid {
  min-height: 76px;
  color: var(--muted);
  font-family: var(--mono);
  font-size: 0.7rem;
}

.footer-grid span:last-child {
  text-align: right;
}

@media (max-width: 900px) {
  :root {
    --rail-width: 112px;
  }

  .nav {
    gap: 18px;
  }

  .project-grid,
  .feature-layout,
  .toolkit-groups {
    grid-template-columns: 1fr;
  }

  .progression {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

  .progression li:nth-child(2) {
    border-right: 0;
  }

  .progression li:nth-child(n + 3) {
    padding-top: 28px;
    border-top: 1px solid var(--line);
  }

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

@media (max-width: 680px) {
  :root {
    --gutter: 20px;
  }

  body {
    background: var(--bg);
  }

  .site-header {
    position: static;
  }

  .header-grid,
  .footer-grid,
  .hero,
  .section {
    grid-template-columns: 1fr;
  }

  .header-grid {
    min-height: auto;
    padding: 18px 0;
  }

  .nav {
    display: none;
  }

  .section-rail {
    flex-direction: row;
    gap: 14px;
    padding: 22px 0 0;
    border-right: 0;
  }

  .hero-content,
  .section-content {
    padding-left: 0;
  }

  .hero {
    min-height: auto;
  }

  .hero-content {
    min-height: auto;
    padding-top: 52px;
    padding-bottom: 72px;
  }

  h1 {
    font-size: clamp(2.75rem, 13vw, 4.8rem);
  }

  h2 {
    font-size: clamp(2.1rem, 10vw, 3.4rem);
  }

  .hero-actions {
    margin-bottom: 54px;
  }

  .hero-meta {
    grid-template-columns: 1fr;
  }

  .hero-meta div {
    padding: 14px 0;
    border-bottom: 1px solid var(--line);
  }

  .decision,
  .principles article {
    grid-template-columns: 42px minmax(0, 1fr);
    gap: 14px;
  }

  .project-grid,
  .feature-layout {
    margin-bottom: 56px;
  }

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

  .progression li,
  .progression li + li {
    min-height: auto;
    padding: 24px 0;
    border-top: 1px solid var(--line);
    border-right: 0;
  }

  .progression li:first-child {
    border-top: 0;
  }

  .progression-year {
    margin-bottom: 18px;
  }

  .experience-header {
    flex-direction: column;
    gap: 12px;
  }

  .timeline::before {
    left: 51px;
  }

  .timeline-item {
    grid-template-columns: 52px minmax(0, 1fr);
    gap: 22px;
  }

  .footer-grid {
    grid-template-columns: 1fr 1fr;
    gap: 12px;
  }
}

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