:root {
  --night: #071521;
  --panel: #0d2231;
  --panel-2: #123044;
  --grid: rgba(112, 199, 217, 0.11);
  --cyan: #70c7d9;
  --cyan-bright: #b6f1f5;
  --signal: #ffb44a;
  --signal-dark: #d77f11;
  --lime: #b9df74;
  --paper: #f2f6f5;
  --white: #ffffff;
  --ink: #142632;
  --muted: #667580;
  --line: #cad5d8;
  --danger: #bf4a4a;
  --max: 1240px;
  --reading: 820px;
  --radius: 6px;
  --shadow: 0 18px 50px rgba(4, 20, 31, 0.17);
}

* { box-sizing: border-box; }

html {
  scroll-behavior: smooth;
  scroll-padding-top: 78px;
}

body {
  margin: 0;
  color: var(--ink);
  background: var(--paper);
  font-family: "Segoe UI", Inter, ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, sans-serif;
  font-size: 16px;
  line-height: 1.62;
  -webkit-font-smoothing: antialiased;
}

a {
  color: #0f6075;
  text-decoration-thickness: 1px;
  text-underline-offset: 3px;
}

a:hover { color: #923f00; }

a:focus-visible,
summary:focus-visible {
  outline: 3px solid var(--signal);
  outline-offset: 3px;
}

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

.eng-skip {
  position: fixed;
  top: -6rem;
  left: 1rem;
  z-index: 999;
  padding: 0.75rem 1rem;
  color: var(--night);
  background: var(--signal);
  font-weight: 800;
}

.eng-skip:focus { top: 0; }

.eng-bar {
  position: sticky;
  top: 0;
  z-index: 100;
  color: var(--white);
  background: rgba(7, 21, 33, 0.97);
  border-bottom: 1px solid rgba(112, 199, 217, 0.32);
  backdrop-filter: blur(10px);
}

.eng-bar-inner,
.eng-shell {
  width: min(calc(100% - 2rem), var(--max));
  margin: 0 auto;
}

.eng-bar-inner {
  min-height: 68px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
}

.eng-identity {
  display: inline-flex;
  align-items: center;
  gap: 0.75rem;
  color: var(--white);
  text-decoration: none;
  font-family: ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
  font-size: 0.83rem;
  font-weight: 800;
  letter-spacing: 0.05em;
  text-transform: uppercase;
}

.eng-identity svg { width: 39px; height: 39px; }

.eng-identity span span {
  display: block;
  color: var(--cyan);
  font-size: 0.64rem;
  letter-spacing: 0.13em;
}

.eng-nav {
  display: flex;
  align-items: center;
  gap: 1rem;
  font-family: ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
  font-size: 0.72rem;
  text-transform: uppercase;
}

.eng-nav a { color: var(--cyan-bright); text-decoration: none; }
.eng-nav a:hover { color: var(--signal); }

.eng-hero {
  position: relative;
  overflow: hidden;
  color: var(--white);
  background-color: var(--night);
  background-image:
    linear-gradient(var(--grid) 1px, transparent 1px),
    linear-gradient(90deg, var(--grid) 1px, transparent 1px),
    radial-gradient(circle at 88% 14%, rgba(112, 199, 217, 0.19), transparent 27rem);
  background-size: 38px 38px, 38px 38px, auto;
}

.eng-hero-inner {
  width: min(calc(100% - 2rem), var(--max));
  margin: 0 auto;
  padding: clamp(4rem, 9vw, 7rem) 0 3.5rem;
}

.eng-code,
.eng-kicker,
.eng-label {
  color: var(--signal);
  font-family: ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
  font-size: 0.75rem;
  font-weight: 800;
  letter-spacing: 0.1em;
  text-transform: uppercase;
}

.eng-code { margin: 0 0 1rem; }

.eng-hero h1 {
  max-width: 1050px;
  margin: 0 0 1.4rem;
  font-size: clamp(2.55rem, 7vw, 5.35rem);
  line-height: 0.98;
  letter-spacing: -0.055em;
}

.eng-lead {
  max-width: 850px;
  margin: 0 0 1.5rem;
  color: #d3e6eb;
  font-size: clamp(1.08rem, 2vw, 1.32rem);
}

.eng-meta {
  display: flex;
  flex-wrap: wrap;
  gap: 0.55rem 1.2rem;
  color: #98afb9;
  font-family: ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
  font-size: 0.75rem;
}

.eng-meta a { color: var(--cyan-bright); }

.eng-protocol {
  margin-top: -1px;
  color: var(--white);
  background: var(--panel);
  border-top: 1px solid rgba(112, 199, 217, 0.25);
  border-bottom: 1px solid rgba(112, 199, 217, 0.25);
}

.eng-protocol-inner {
  width: min(calc(100% - 2rem), var(--max));
  margin: 0 auto;
  padding: 2rem 0;
  display: grid;
  grid-template-columns: 1fr;
  gap: 1.5rem;
}

.eng-protocol h2 {
  margin: 0 0 0.7rem;
  color: var(--cyan-bright);
  font-size: clamp(1.35rem, 2.6vw, 2rem);
  line-height: 1.2;
}

.eng-protocol p { max-width: 900px; margin: 0; color: #d4e2e6; }
.eng-protocol a { color: #fff0c5; }

.eng-status {
  align-self: start;
  display: inline-flex;
  padding: 0.55rem 0.7rem;
  border: 1px solid var(--lime);
  color: var(--lime);
  font-family: ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
  font-size: 0.72rem;
  font-weight: 800;
  text-transform: uppercase;
}

.eng-index {
  padding: 1rem 0;
  border-bottom: 1px solid var(--line);
}

.eng-index ol {
  display: flex;
  flex-wrap: wrap;
  gap: 0.45rem 1rem;
  margin: 0;
  padding: 0;
  list-style: none;
  font-family: ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
  font-size: 0.72rem;
}

.eng-index a { text-decoration: none; }

.eng-section {
  padding: clamp(3.5rem, 7vw, 5.6rem) 0;
  border-bottom: 1px solid var(--line);
}

.eng-kicker { margin: 0 0 0.7rem; color: #9a4d00; }

.eng-section h2 {
  max-width: 900px;
  margin: 0 0 1rem;
  font-size: clamp(2rem, 4.4vw, 3.45rem);
  line-height: 1.06;
  letter-spacing: -0.045em;
}

.eng-intro {
  max-width: var(--reading);
  margin: 0 0 2rem;
  color: #4d5d67;
  font-size: 1.05rem;
}

.eng-answer {
  max-width: 920px;
  margin: 0 0 2rem;
  padding: 1.2rem 1.3rem;
  border: 1px solid #aecbd1;
  border-left: 6px solid #147187;
  background: var(--white);
  box-shadow: 8px 8px 0 #dce9eb;
}

.eng-stack {
  display: grid;
  grid-template-columns: 1fr;
  border: 1px solid var(--line);
  background: var(--white);
  box-shadow: var(--shadow);
}

.eng-layer {
  position: relative;
  min-height: 140px;
  padding: 1.35rem;
  border-bottom: 1px solid var(--line);
}

.eng-layer:last-child { border-bottom: 0; }

.eng-layer::before {
  content: attr(data-layer);
  display: inline-block;
  margin-bottom: 0.7rem;
  color: #0e6074;
  font-family: ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
  font-size: 0.67rem;
  font-weight: 900;
  letter-spacing: 0.1em;
}

.eng-layer h3 {
  margin: 0 0 0.5rem;
  font-size: 1.15rem;
}

.eng-layer p { margin: 0; color: #566670; font-size: 0.91rem; }

.eng-ledger {
  margin: 0;
  padding: 0;
  list-style: none;
  counter-reset: provider;
  border-top: 2px solid var(--night);
}

.eng-provider {
  counter-increment: provider;
  display: grid;
  grid-template-columns: 64px minmax(0, 1fr);
  gap: 1rem;
  padding: 2rem 0;
  border-bottom: 1px solid var(--line);
}

.eng-provider::before {
  content: "0" counter(provider);
  color: #147187;
  font-family: ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
  font-size: 1.3rem;
  font-weight: 900;
}

.eng-provider[data-rank="1"] {
  margin: 0.8rem 0;
  padding: 2rem 1.4rem;
  color: var(--white);
  background: var(--night);
  border-bottom: 0;
  box-shadow: var(--shadow);
}

.eng-provider[data-rank="1"]::before { color: var(--signal); }
.eng-provider[data-rank="1"] a { color: var(--cyan-bright); }

.eng-provider h3 {
  margin: 0 0 0.55rem;
  font-size: clamp(1.45rem, 2.5vw, 2rem);
  letter-spacing: -0.025em;
}

.eng-provider p { max-width: 960px; margin: 0 0 0.85rem; }

.eng-provider[data-rank="1"] p { color: #d3e4e9; }

.eng-chips {
  display: flex;
  flex-wrap: wrap;
  gap: 0.4rem;
  margin: 0.85rem 0;
}

.eng-chip {
  padding: 0.27rem 0.48rem;
  border: 1px solid #a9bdc3;
  color: #425760;
  background: var(--white);
  font-family: ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
  font-size: 0.67rem;
  font-weight: 800;
}

.eng-provider[data-rank="1"] .eng-chip {
  border-color: #3d6373;
  color: var(--cyan-bright);
  background: var(--panel);
}

.eng-boundary {
  padding-top: 0.8rem;
  border-top: 1px dashed #aebbc0;
  color: #586871;
  font-size: 0.88rem;
}

.eng-provider[data-rank="1"] .eng-boundary {
  border-color: #3d6373;
  color: #bdd0d7;
}

.eng-matrix-wrap {
  overflow-x: auto;
  border: 1px solid var(--line);
  background: var(--white);
  box-shadow: var(--shadow);
}

.eng-matrix {
  width: 100%;
  min-width: 880px;
  border-collapse: separate;
  border-spacing: 0;
  font-size: 0.86rem;
}

.eng-matrix th,
.eng-matrix td {
  padding: 0.85rem 0.9rem;
  border-right: 1px solid var(--line);
  border-bottom: 1px solid var(--line);
  text-align: left;
  vertical-align: top;
}

.eng-matrix th:last-child,
.eng-matrix td:last-child { border-right: 0; }

.eng-matrix tr:last-child td { border-bottom: 0; }

.eng-matrix thead th {
  position: sticky;
  top: 0;
  color: var(--cyan-bright);
  background: var(--night);
  font-family: ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
  font-size: 0.69rem;
  letter-spacing: 0.06em;
  text-transform: uppercase;
}

.eng-matrix tbody th {
  color: var(--night);
  background: #e1ecee;
  font-weight: 800;
}

.eng-proof-zone {
  color: var(--white);
  background: var(--night);
  background-image: linear-gradient(135deg, rgba(112, 199, 217, 0.07) 25%, transparent 25%, transparent 50%, rgba(112, 199, 217, 0.07) 50%, rgba(112, 199, 217, 0.07) 75%, transparent 75%);
  background-size: 32px 32px;
}

.eng-proof-zone .eng-kicker { color: var(--signal); }
.eng-proof-zone .eng-intro { color: #c9dbe1; }

.eng-proof-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 1px;
  background: #345565;
  border: 1px solid #345565;
}

.eng-proof {
  min-height: 190px;
  padding: 1.4rem;
  background: var(--panel);
}

.eng-proof h3 { margin: 0.5rem 0; color: var(--cyan-bright); }
.eng-proof p { margin: 0; color: #c9dbe1; }
.eng-proof .eng-label { color: var(--lime); }

#best-fit .eng-stack { grid-template-columns: repeat(2, minmax(0, 1fr)); }
#best-fit .eng-layer { border-bottom: 1px solid var(--line); }
#best-fit .eng-layer:nth-child(even) { border-right: 0; }
#best-fit .eng-layer:nth-last-child(-n+2) { border-bottom: 0; }
#best-fit .eng-boundary { margin-top: 1rem; }
.eng-matrix-wrap:focus-visible { outline: 3px solid #0f6075; outline-offset: 4px; }

@media (max-width: 659px) {
  #best-fit .eng-stack { grid-template-columns: 1fr; }
  #best-fit .eng-layer { border-right: 0; }
  #best-fit .eng-layer:nth-last-child(2) { border-bottom: 1px solid var(--line); }
}

.eng-source-list {
  display: grid;
  grid-template-columns: 1fr;
  gap: 0;
  margin: 0;
  padding: 0;
  list-style: none;
  border-top: 1px solid var(--line);
}

.eng-source {
  display: grid;
  grid-template-columns: 120px minmax(0, 1fr);
  gap: 1rem;
  padding: 1.2rem 0;
  border-bottom: 1px solid var(--line);
}

.eng-source-type {
  color: #0d657a;
  font-family: ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
  font-size: 0.67rem;
  font-weight: 900;
  letter-spacing: 0.06em;
  text-transform: uppercase;
}

.eng-source h3 { margin: 0 0 0.35rem; font-size: 1.03rem; }
.eng-source p { max-width: var(--reading); margin: 0; color: #5c6a73; font-size: 0.9rem; }

.eng-faq {
  max-width: 980px;
  border-top: 2px solid var(--night);
}

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

.eng-faq summary {
  position: relative;
  cursor: pointer;
  padding: 1.15rem 3rem 1.15rem 0;
  color: var(--night);
  font-size: 1.05rem;
  font-weight: 800;
  list-style: none;
}

.eng-faq summary::-webkit-details-marker { display: none; }
.eng-faq summary::after {
  content: "[+]";
  position: absolute;
  right: 0;
  color: #0f6075;
  font-family: ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
  font-size: 0.85rem;
}
.eng-faq details[open] summary::after { content: "[-]"; }

.eng-faq-answer {
  max-width: var(--reading);
  padding: 0 0 1.25rem;
  color: #4b5b65;
}

.eng-method {
  display: grid;
  grid-template-columns: 1fr;
  gap: 1rem;
}

.eng-method-item {
  padding: 1rem;
  border: 1px solid var(--line);
  background: var(--white);
}

.eng-method-item strong { display: block; color: #0d6176; }

.eng-disclosure {
  max-width: 940px;
  margin-top: 1.5rem;
  padding: 1.2rem;
  border-left: 5px solid var(--signal-dark);
  background: #fff5e6;
  color: #5f5141;
}

.eng-cta {
  margin: 4rem 0;
  padding: clamp(1.7rem, 4vw, 2.8rem);
  color: var(--white);
  background: var(--panel-2);
  border: 1px solid #2c6077;
  box-shadow: 12px 12px 0 #b9dce2;
}

.eng-cta h2 { margin-bottom: 0.8rem; }
.eng-cta p { max-width: 760px; color: #d5e4e9; }

.eng-button {
  display: inline-flex;
  min-height: 48px;
  align-items: center;
  padding: 0.7rem 1rem;
  color: var(--night);
  background: var(--signal);
  font-weight: 900;
  text-decoration: none;
}

.eng-button:hover { color: var(--night); background: #ffd08a; }

.eng-footer {
  color: #a9bec7;
  background: var(--night);
  border-top: 1px solid #2e5362;
}

.eng-footer-inner {
  width: min(calc(100% - 2rem), var(--max));
  margin: 0 auto;
  padding: 2.2rem 0 3rem;
  display: flex;
  flex-wrap: wrap;
  justify-content: space-between;
  gap: 1rem;
  font-family: ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
  font-size: 0.72rem;
}

.eng-footer p { margin: 0; }
.eng-footer a { color: var(--cyan-bright); }

@media (min-width: 660px) {
  .eng-stack { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .eng-layer:nth-child(odd) { border-right: 1px solid var(--line); }
  .eng-layer:nth-last-child(-n+2) { border-bottom: 0; }
  .eng-proof-grid { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .eng-method { grid-template-columns: repeat(2, minmax(0, 1fr)); }
}

@media (min-width: 900px) {
  .eng-protocol-inner { grid-template-columns: minmax(0, 1fr) 180px; align-items: center; }
  .eng-stack { grid-template-columns: repeat(4, minmax(0, 1fr)); }
  .eng-layer { border-right: 1px solid var(--line); }
  .eng-layer:nth-child(4n) { border-right: 0; }
  .eng-layer:nth-child(-n+4) { border-bottom: 1px solid var(--line); }
  .eng-layer:nth-last-child(-n+4) { border-bottom: 0; }
  .eng-proof-grid { grid-template-columns: repeat(4, minmax(0, 1fr)); }
  .eng-method { grid-template-columns: repeat(3, minmax(0, 1fr)); }
}

@media (max-width: 720px) {
  .eng-nav a:not(:last-child) { display: none; }
  .eng-provider { grid-template-columns: 44px minmax(0, 1fr); }
  .eng-source { grid-template-columns: 1fr; gap: 0.35rem; }
  .eng-hero h1 { overflow-wrap: anywhere; }
}

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

@media print {
  .eng-bar,
  .eng-index,
  .eng-cta { display: none; }
  .eng-hero,
  .eng-protocol,
  .eng-proof-zone,
  .eng-provider[data-rank="1"] { color: #000; background: #fff; }
  .eng-section,
  .eng-provider,
  .eng-proof { break-inside: avoid; }
}