/* ==========================================================================
   Responsible Cloud Infrastructure Standard — stylesheet
   Design concept: read like a working standards document (think an RFC or
   ISO draft), not a SaaS marketing page. Paper background, a serif for
   headings, monospace for clause numbers/labels/data, hairline rules
   instead of shadows and rounded cards, one restrained "stamp" accent.
   ========================================================================== */

@import url('https://fonts.googleapis.com/css2?family=Source+Serif+4:opsz,wght@8..60,500;8..60,600;8..60,700&display=swap');

:root {
  /* Color */
  --paper: #EDEAE1;
  --paper-2: #E3DFD1;
  --ink: #1A1F2A;
  --ink-soft: #4B5264;
  --ink-faint: #8A8F7F;
  --line: #C9C2AC;
  --line-strong: #B3AA8C;

  --accent: #8B3A32;
  --accent-dark: #6E2D27;
  --accent-wash: #F1E1D9;

  --panel: #15181F;
  --panel-2: #1D2129;
  --panel-line: #333947;
  --panel-text: #E9E5D8;
  --panel-text-soft: #9CA0AC;

  /* Type */
  --font-serif: 'Source Serif 4', Georgia, 'Times New Roman', serif;
  --font-sans: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
  --font-mono: 'IBM Plex Mono', 'SFMono-Regular', Consolas, monospace;

  /* Layout */
  --container: 1180px;
  --gutter: 28px;
  --rule: 1px solid var(--line);
}

/* ---------- Reset / base ---------- */
* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  * { animation-duration: 0.001ms !important; animation-iteration-count: 1 !important; transition-duration: 0.001ms !important; }
}

body {
  margin: 0;
  background: var(--paper);
  color: var(--ink);
  font-family: var(--font-sans);
  font-size: 16px;
  line-height: 1.55;
  -webkit-font-smoothing: antialiased;
}

h1, h2, h3 {
  font-family: var(--font-serif);
  color: var(--ink);
  margin: 0;
  font-weight: 600;
  letter-spacing: -0.01em;
}

p { margin: 0 0 1em; }
p:last-child { margin-bottom: 0; }

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

:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 3px;
}

img, svg { max-width: 100%; display: block; }

.container {
  max-width: var(--container);
  margin: 0 auto;
  padding: 0 var(--gutter);
}

/* ---------- Shared section rhythm ---------- */
.section {
  padding: 96px 0;
  border-top: var(--rule);
}
.section:first-of-type { border-top: none; }

.section-kicker {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  font-family: var(--font-mono);
  font-size: 12.5px;
  letter-spacing: 0.06em;
  color: var(--accent);
  margin: 0 0 18px;
}
.section-kicker::before {
  content: '';
  width: 18px;
  height: 1px;
  background: var(--accent);
  display: inline-block;
}
.section-kicker.light { color: #D8A99A; }
.section-kicker.light::before { background: #D8A99A; }

.section h2 {
  font-size: clamp(28px, 3.4vw, 40px);
  line-height: 1.18;
  max-width: 16ch;
}

.section-lede {
  font-family: var(--font-sans);
  color: var(--ink-soft);
  font-size: 17px;
  max-width: 62ch;
  margin-top: 18px;
}

.body-large {
  font-size: 17px;
  color: var(--ink-soft);
  max-width: 52ch;
}
.body-large p { margin-bottom: 1.1em; }

/* ---------- Buttons ---------- */
.btn {
  display: inline-block;
  font-family: var(--font-sans);
  font-weight: 600;
  font-size: 14.5px;
  padding: 13px 22px;
  border: 1.5px solid var(--ink);
  background: var(--ink);
  color: var(--paper);
  border-radius: 2px;
  transition: background 0.15s ease, color 0.15s ease, border-color 0.15s ease;
}
.btn:hover { background: var(--accent); border-color: var(--accent); }

.btn-secondary {
  background: transparent;
  color: var(--ink);
  border-color: var(--ink);
}
.btn-secondary:hover { background: var(--ink); color: var(--paper); }

.btn-small { padding: 9px 16px; font-size: 13.5px; }

.btn-light {
  background: transparent;
  color: var(--panel-text);
  border: 1.5px solid var(--panel-text-soft);
}
.btn-light:hover {
  background: var(--panel-text);
  color: var(--panel);
  border-color: var(--panel-text);
}

.text-link {
  font-family: var(--font-mono);
  font-size: 14px;
  color: var(--panel-text);
  border-bottom: 1px solid var(--panel-line);
  padding-bottom: 2px;
  transition: border-color 0.15s ease, color 0.15s ease;
}
.text-link:hover { color: #D8A99A; border-color: #D8A99A; }

/* ---------- Header ---------- */
.site-header {
  position: sticky;
  top: 0;
  z-index: 40;
  background: rgba(237, 234, 225, 0.92);
  backdrop-filter: saturate(140%) blur(6px);
  border-bottom: var(--rule);
}

.nav-wrap {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding-top: 16px;
  padding-bottom: 16px;
  gap: 20px;
}

.brand {
  display: flex;
  align-items: center;
  gap: 10px;
  font-family: var(--font-sans);
}

.brand-mark {
  font-family: var(--font-mono);
  font-size: 12.5px;
  font-weight: 600;
  letter-spacing: 0.05em;
  border: 1.5px solid var(--ink);
  color: var(--ink);
  padding: 4px 7px;
  line-height: 1;
}

.brand-text {
  font-weight: 600;
  font-size: 14.5px;
  color: var(--ink);
  max-width: 21ch;
  line-height: 1.2;
}

.nav-toggle { display: none; }

.nav-links {
  display: flex;
  align-items: center;
  gap: 26px;
  font-size: 14.5px;
  color: var(--ink-soft);
  flex-wrap: wrap;
}

.nav-links a:not(.btn) {
  position: relative;
  padding-bottom: 2px;
}
.nav-links a:not(.btn)::after {
  content: '';
  position: absolute;
  left: 0; right: 100%;
  bottom: -2px;
  height: 1px;
  background: var(--accent);
  transition: right 0.18s ease;
}
.nav-links a:not(.btn):hover { color: var(--ink); }
.nav-links a:not(.btn):hover::after { right: 0; }

/* ---------- Hero ---------- */
.hero { padding: 76px 0 96px; }

.hero-grid {
  display: grid;
  grid-template-columns: 1.15fr 0.85fr;
  gap: 64px;
  align-items: start;
}

.eyebrow {
  font-family: var(--font-mono);
  font-size: 12.5px;
  letter-spacing: 0.06em;
  color: var(--ink-faint);
  margin: 0 0 22px;
}

.hero h1 {
  font-size: clamp(34px, 4.6vw, 54px);
  line-height: 1.08;
  max-width: 15ch;
}

.hero-copy {
  font-size: 18px;
  color: var(--ink-soft);
  max-width: 52ch;
  margin-top: 22px;
}

.hero-actions {
  display: flex;
  gap: 14px;
  margin-top: 34px;
  flex-wrap: wrap;
}

.hero-note {
  margin-top: 34px;
  padding-top: 22px;
  border-top: var(--rule);
  font-size: 15px;
  color: var(--ink-soft);
  max-width: 46ch;
}
.hero-note strong { color: var(--ink); font-weight: 600; }

.hero-panel {
  background: var(--panel);
  color: var(--panel-text);
  padding: 26px 24px;
  border-radius: 2px;
}

.panel-label {
  font-family: var(--font-mono);
  font-size: 11.5px;
  letter-spacing: 0.08em;
  color: var(--panel-text-soft);
  margin-bottom: 18px;
}

.stack-item {
  display: grid;
  grid-template-columns: 26px 1fr;
  column-gap: 14px;
  row-gap: 2px;
  padding: 13px 0;
  border-top: 1px solid var(--panel-line);
}
.stack-item:first-of-type { border-top: none; }

.stack-item span {
  font-family: var(--font-mono);
  font-size: 12.5px;
  color: #D8A99A;
  padding-top: 2px;
}

.stack-item b {
  font-family: var(--font-sans);
  font-weight: 600;
  font-size: 14.5px;
  color: var(--panel-text);
  grid-column: 2;
}

.stack-item small {
  grid-column: 2;
  font-size: 12.5px;
  color: var(--panel-text-soft);
}

/* ---------- Intro band ---------- */
.intro-band { background: var(--paper); }

.intro-grid {
  display: grid;
  grid-template-columns: 0.85fr 1.15fr;
  gap: 56px;
}

.intro-grid h2 { max-width: 14ch; }

/* ---------- Six-domain cards ---------- */
.card-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 1px;
  background: var(--line);
  border: var(--rule);
  margin-top: 44px;
}

.card {
  background: var(--paper);
  padding: 28px 24px 26px;
  position: relative;
}

.card .num {
  display: block;
  font-family: var(--font-mono);
  font-size: 13px;
  color: var(--accent);
  margin-bottom: 30px;
}

.card h3 {
  font-family: var(--font-sans);
  font-weight: 600;
  font-size: 16.5px;
  margin-bottom: 10px;
  letter-spacing: -0.005em;
}

.card p {
  font-size: 14.5px;
  color: var(--ink-soft);
}

/* ---------- Operating model (dark) ---------- */
.section-dark {
  background: var(--panel);
  color: var(--panel-text);
  border-top: none;
}

.section-dark h2 { color: var(--panel-text); }

.flow-grid {
  display: grid;
  grid-template-columns: repeat(6, 1fr);
  gap: 0;
  margin-top: 48px;
  position: relative;
}

.flow-step {
  padding: 0 18px 0 0;
  position: relative;
}

.flow-step:not(:last-child)::after {
  content: '';
  position: absolute;
  top: 15px;
  left: 0;
  right: 18px;
  height: 1px;
  background: var(--panel-line);
}

.flow-step span {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 30px;
  height: 30px;
  border: 1.5px solid #D8A99A;
  color: #D8A99A;
  font-family: var(--font-mono);
  font-size: 13px;
  border-radius: 50%;
  background: var(--panel);
  position: relative;
  z-index: 1;
  margin-bottom: 16px;
}

.flow-step h3 {
  font-family: var(--font-sans);
  font-weight: 600;
  font-size: 15.5px;
  color: var(--panel-text);
  margin-bottom: 8px;
}

.flow-step p {
  font-size: 13.5px;
  color: var(--panel-text-soft);
  line-height: 1.5;
}

/* ---------- Evidence / PRRS ---------- */
.split {
  display: grid;
  grid-template-columns: 0.95fr 1.05fr;
  gap: 64px;
  align-items: start;
}

.split h2 { max-width: 13ch; }

.formula {
  margin-top: 32px;
  border: 1.5px solid var(--ink);
  padding: 24px 22px;
  position: relative;
}
.formula::before {
  content: '';
  position: absolute;
  inset: 5px;
  border: 1px solid var(--line-strong);
  pointer-events: none;
}

.formula span {
  display: block;
  font-family: var(--font-mono);
  font-size: 13px;
  color: var(--accent);
  letter-spacing: 0.04em;
  margin-bottom: 10px;
}

.formula strong {
  display: block;
  font-family: var(--font-serif);
  font-size: 21px;
  font-weight: 600;
  color: var(--ink);
  line-height: 1.3;
}

.formula small {
  display: block;
  margin-top: 10px;
  font-size: 13px;
  color: var(--ink-faint);
}

.evidence-list {
  display: grid;
  gap: 0;
  border-top: var(--rule);
}

.evidence-list > div {
  display: grid;
  grid-template-columns: 130px 1fr;
  gap: 18px;
  padding: 17px 0;
  border-bottom: var(--rule);
}

.evidence-list b {
  font-family: var(--font-sans);
  font-weight: 600;
  font-size: 14.5px;
  color: var(--ink);
}

.evidence-list span {
  font-size: 14.5px;
  color: var(--ink-soft);
}

/* ---------- Architecture map ---------- */
.architecture-section { background: var(--paper-2); }

.architecture-map {
  margin-top: 44px;
  display: flex;
  flex-direction: column;
  align-items: center;
  max-width: 420px;
  margin-left: auto;
  margin-right: auto;
}

.architecture-map div {
  width: 100%;
  text-align: center;
  border: 1.5px solid var(--ink);
  background: var(--paper);
  padding: 13px 18px;
  font-family: var(--font-sans);
  font-weight: 600;
  font-size: 14.5px;
  color: var(--ink);
}

.architecture-map span {
  font-family: var(--font-mono);
  color: var(--accent);
  padding: 4px 0;
  font-size: 14px;
}

.map-caption {
  margin-top: 26px;
  text-align: center;
  font-size: 14.5px;
  color: var(--ink-soft);
  max-width: 56ch;
  margin-left: auto;
  margin-right: auto;
}

/* ---------- Research agenda ---------- */
.research-grid {
  margin-top: 44px;
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  column-gap: 40px;
  row-gap: 30px;
}

.research-grid article {
  padding-top: 18px;
  border-top: 2px solid var(--ink);
}

.research-grid h3 {
  font-family: var(--font-mono);
  font-weight: 500;
  font-size: 13px;
  letter-spacing: 0.02em;
  color: var(--accent);
  margin-bottom: 10px;
}

.research-grid p {
  font-size: 14.5px;
  color: var(--ink-soft);
}

/* ---------- Principles ---------- */
.principles-section { background: var(--paper); }

.principles-list {
  margin-top: 40px;
  border-top: var(--rule);
  max-width: 74ch;
}

.principles-list > div {
  display: grid;
  grid-template-columns: 48px 1fr;
  gap: 18px;
  padding: 19px 0;
  border-bottom: var(--rule);
}

.principles-list span {
  font-family: var(--font-mono);
  font-size: 13px;
  color: var(--accent);
  padding-top: 2px;
}

.principles-list p {
  font-family: var(--font-serif);
  font-size: 17px;
  line-height: 1.5;
  color: var(--ink);
}
.principles-list strong { font-weight: 600; }

/* ---------- Roadmap timeline ---------- */
.section-muted { background: var(--paper-2); }

.timeline {
  margin-top: 48px;
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 32px;
}

.timeline > div {
  padding-top: 18px;
  border-top: 3px solid var(--ink);
}

.timeline span {
  display: block;
  font-family: var(--font-mono);
  font-size: 13px;
  color: var(--accent);
  margin-bottom: 12px;
}

.timeline h3 {
  font-family: var(--font-sans);
  font-weight: 600;
  font-size: 16px;
  margin-bottom: 8px;
}

.timeline p {
  font-size: 14px;
  color: var(--ink-soft);
}

/* ---------- Comparison / positioning ---------- */
.comparison-section h2 { max-width: 20ch; }

.tag-cloud {
  margin-top: 32px;
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
}

.tag-cloud span {
  font-family: var(--font-mono);
  font-size: 13px;
  color: var(--ink-soft);
  border: 1px solid var(--line-strong);
  padding: 7px 12px;
}

/* ---------- CTA ---------- */
.cta-section {
  background: var(--panel);
  color: var(--panel-text);
  border-top: none;
}

.cta-box {
  display: grid;
  grid-template-columns: 1.2fr 0.8fr;
  gap: 48px;
  align-items: center;
}

.cta-box h2 {
  color: var(--panel-text);
  max-width: 16ch;
}

.cta-box p {
  color: var(--panel-text-soft);
  font-size: 15.5px;
  margin-top: 18px;
  max-width: 52ch;
}

.cta-actions {
  display: flex;
  flex-direction: column;
  align-items: flex-start;
  gap: 18px;
}

/* ---------- Footer ---------- */
.footer {
  background: var(--paper-2);
  border-top: var(--rule);
  padding: 56px 0 0;
}

.footer-grid {
  display: grid;
  grid-template-columns: 1.4fr 1fr;
  gap: 48px;
  padding-bottom: 44px;
}

.footer-brand { margin-bottom: 16px; }

.footer-grid > div:first-child p {
  color: var(--ink-soft);
  font-size: 14.5px;
  max-width: 48ch;
}

.footer-meta p {
  font-size: 14px;
  color: var(--ink-soft);
  margin-bottom: 8px;
}
.footer-meta strong { color: var(--ink); }

.footer-bottom {
  border-top: var(--rule);
  padding: 18px 0;
  font-size: 13px;
  color: var(--ink-faint);
}

/* ---------- Responsive ---------- */
@media (max-width: 980px) {
  .hero-grid,
  .intro-grid,
  .split,
  .cta-box,
  .footer-grid {
    grid-template-columns: 1fr;
  }

  .hero-panel { max-width: 460px; }

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

  .flow-grid {
    grid-template-columns: repeat(3, 1fr);
    row-gap: 36px;
  }
  .flow-step:nth-child(3)::after { display: none; }

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

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

  .cta-actions { align-items: flex-start; }
}

@media (max-width: 620px) {
  .section { padding: 64px 0; }
  .hero { padding: 48px 0 64px; }

  .nav-links { gap: 16px; }
  .nav-links .btn-small { order: -1; width: 100%; text-align: center; }

  .card-grid { grid-template-columns: 1fr; }
  .flow-grid { grid-template-columns: 1fr; row-gap: 30px; }
  .flow-step::after { display: none; }

  .research-grid { grid-template-columns: 1fr; }
  .timeline { grid-template-columns: 1fr; }

  .evidence-list > div,
  .principles-list > div {
    grid-template-columns: 1fr;
    row-gap: 6px;
  }

  .architecture-map { max-width: 100%; }
}