/* Enterprise software as algebraic specifications */

:root {
  --bg: #f5f3ee;
  --bg-2: #ece9e1;
  --surface: #fbfaf7;
  --ink: #15171b;
  --ink-2: #3b3f47;
  --ink-soft: #6b6f78;
  --line: rgba(21, 23, 27, 0.12);
  --line-strong: rgba(21, 23, 27, 0.24);
  --accent: #2f45d6;
  --accent-soft: rgba(47, 69, 214, 0.09);
  --accent-ink: #ffffff;
  --open: #157a5c;
  --open-soft: rgba(21, 122, 92, 0.09);
  --grid: rgba(21, 23, 27, 0.055);
  --shadow: 0 1px 0 rgba(255, 255, 255, 0.6) inset, 0 18px 40px -28px rgba(20, 24, 40, 0.35);

  --f-serif: "Newsreader", Georgia, "Times New Roman", serif;
  --f-sans: "Inter Tight", system-ui, -apple-system, "Segoe UI", sans-serif;
  --f-mono: "JetBrains Mono", ui-monospace, SFMono-Regular, Menlo, monospace;
  --gutter: max(16px, env(safe-area-inset-left));
  --measure: 40rem;
  color-scheme: light;
}

@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) {
    --bg: #0d0f12;
    --bg-2: #14171c;
    --surface: #12151a;
    --ink: #eceae4;
    --ink-2: #c4c3be;
    --ink-soft: #8d9099;
    --line: rgba(236, 234, 228, 0.11);
    --line-strong: rgba(236, 234, 228, 0.22);
    --accent: #8b9bff;
    --accent-soft: rgba(139, 155, 255, 0.12);
    --accent-ink: #0d0f12;
    --open: #5fd0a8;
    --open-soft: rgba(95, 208, 168, 0.1);
    --grid: rgba(236, 234, 228, 0.045);
    --shadow: 0 18px 40px -28px rgba(0, 0, 0, 0.8);
    color-scheme: dark;
  }
}
:root[data-theme="dark"] {
  --bg: #0d0f12;
  --bg-2: #14171c;
  --surface: #12151a;
  --ink: #eceae4;
  --ink-2: #c4c3be;
  --ink-soft: #8d9099;
  --line: rgba(236, 234, 228, 0.11);
  --line-strong: rgba(236, 234, 228, 0.22);
  --accent: #8b9bff;
  --accent-soft: rgba(139, 155, 255, 0.12);
  --accent-ink: #0d0f12;
  --open: #5fd0a8;
  --open-soft: rgba(95, 208, 168, 0.1);
  --grid: rgba(236, 234, 228, 0.045);
  --shadow: 0 18px 40px -28px rgba(0, 0, 0, 0.8);
  color-scheme: dark;
}

*, *::before, *::after { box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; scroll-behavior: smooth; scroll-padding-top: 5rem; }
@media (prefers-reduced-motion: reduce) { html { scroll-behavior: auto; } }
body {
  margin: 0;
  background: var(--bg);
  color: var(--ink);
  font-family: var(--f-serif);
  font-size: clamp(1.075rem, 1rem + 0.3vw, 1.2rem);
  line-height: 1.62;
  font-optical-sizing: auto;
  text-rendering: optimizeLegibility;
  -webkit-font-smoothing: antialiased;
  overflow-x: hidden;
}
a { color: inherit; }
::selection { background: var(--accent); color: var(--accent-ink); }
:focus-visible { outline: 2px solid var(--accent); outline-offset: 3px; border-radius: 4px; }

.wrap { width: 100%; max-width: 72rem; margin: 0 auto; padding-inline: var(--gutter); }

/* progress */
.progress { position: fixed; inset: 0 0 auto 0; height: 2px; z-index: 30; pointer-events: none; }
.progress span { display: block; height: 100%; width: 100%; background: var(--accent); transform-origin: 0 50%; transform: scaleX(0); }

/* header */
.top {
  position: sticky; top: 0; z-index: 20;
  display: flex; align-items: center; justify-content: space-between; gap: 1rem;
  padding: 0.85rem var(--gutter);
  background: color-mix(in srgb, var(--bg) 82%, transparent);
  backdrop-filter: saturate(1.4) blur(12px);
  -webkit-backdrop-filter: saturate(1.4) blur(12px);
  border-bottom: 1px solid transparent;
  transition: border-color 0.2s;
}
.top.scrolled { border-bottom-color: var(--line); }
.mark { display: inline-flex; align-items: center; gap: 0.55rem; text-decoration: none; font-family: var(--f-sans); font-weight: 600; font-size: 0.95rem; letter-spacing: -0.01em; }
.mark svg { width: 1.35rem; height: 1.35rem; color: var(--accent); }
.top-cta {
  font-family: var(--f-sans); font-weight: 600; font-size: 0.85rem; text-decoration: none;
  padding: 0.45rem 0.9rem; border-radius: 999px; border: 1px solid var(--line-strong);
  transition: background 0.15s, border-color 0.15s, color 0.15s;
}
.top-cta:hover { background: var(--ink); color: var(--bg); border-color: var(--ink); }

/* hero */
.hero { position: relative; padding: clamp(3.5rem, 10vw, 8rem) 0 clamp(3rem, 7vw, 5.5rem); overflow: hidden; border-bottom: 1px solid var(--line); }
.hero-grid {
  position: absolute; inset: 0; pointer-events: none;
  background-image:
    linear-gradient(var(--grid) 1px, transparent 1px),
    linear-gradient(90deg, var(--grid) 1px, transparent 1px);
  background-size: 32px 32px;
  background-position: -1px -1px;
  mask-image: radial-gradient(ellipse 80% 90% at 70% 10%, #000 30%, transparent 75%);
  -webkit-mask-image: radial-gradient(ellipse 80% 90% at 70% 10%, #000 30%, transparent 75%);
}
.hero .wrap { position: relative; }
.kicker {
  display: inline-flex; align-items: center; gap: 0.55rem; margin: 0 0 1.75rem;
  font-family: var(--f-mono); font-size: 0.78rem; letter-spacing: 0.04em; text-transform: uppercase; color: var(--ink-2);
  padding: 0.4rem 0.8rem 0.4rem 0.65rem; border: 1px solid var(--line-strong); border-radius: 999px; background: var(--surface);
}
.dot { width: 0.5rem; height: 0.5rem; border-radius: 50%; background: var(--open); box-shadow: 0 0 0 0 var(--open); animation: pulse 2.4s infinite; }
@keyframes pulse { 0% { box-shadow: 0 0 0 0 color-mix(in srgb, var(--open) 55%, transparent); } 70% { box-shadow: 0 0 0 9px transparent; } 100% { box-shadow: 0 0 0 0 transparent; } }
@media (prefers-reduced-motion: reduce) { .dot { animation: none; } }
h1 {
  margin: 0; max-width: 15ch;
  font-family: var(--f-sans); font-weight: 700;
  font-size: clamp(2.5rem, 1.4rem + 5.4vw, 5.6rem);
  line-height: 0.98; letter-spacing: -0.035em;
  text-wrap: balance;
}
h1 em { font-family: var(--f-serif); font-style: italic; font-weight: 400; letter-spacing: -0.02em; color: var(--accent); }
.lede { margin: 2rem 0 0; max-width: 34rem; font-size: clamp(1.2rem, 1.05rem + 0.6vw, 1.45rem); line-height: 1.45; color: var(--ink-2); text-wrap: pretty; }
.byline { margin: 1.75rem 0 0; font-family: var(--f-mono); font-size: 0.78rem; color: var(--ink-soft); letter-spacing: 0.02em; }

/* layout */
.layout { display: grid; grid-template-columns: minmax(0, 1fr); gap: 3rem; padding-block: clamp(2.5rem, 6vw, 4.5rem) 2rem; }
@media (min-width: 64rem) {
  .layout { grid-template-columns: 13rem minmax(0, var(--measure)); justify-content: center; gap: 4.5rem; }
}
.toc { display: none; }
@media (min-width: 64rem) {
  .toc { display: block; position: sticky; top: 6rem; align-self: start; font-family: var(--f-sans); font-size: 0.85rem; }
  .toc-title { margin: 0 0 0.9rem; font-family: var(--f-mono); font-size: 0.7rem; text-transform: uppercase; letter-spacing: 0.08em; color: var(--ink-soft); }
  .toc ol { list-style: none; margin: 0; padding: 0; border-left: 1px solid var(--line); counter-reset: toc; }
  .toc li { counter-increment: toc; }
  .toc a {
    display: block; padding: 0.4rem 0 0.4rem 1rem; margin-left: -1px; border-left: 2px solid transparent;
    text-decoration: none; color: var(--ink-soft); line-height: 1.35; transition: color 0.15s, border-color 0.15s;
  }
  .toc a::before { content: counter(toc, decimal-leading-zero) "  "; font-family: var(--f-mono); font-size: 0.72rem; opacity: 0.7; white-space: pre; }
  .toc a:hover { color: var(--ink); }
  .toc a.active { color: var(--ink); border-left-color: var(--accent); }
}

/* prose */
.prose { min-width: 0; max-width: var(--measure); margin-inline: auto; width: 100%; }
.prose p { margin: 0 0 1.25em; text-wrap: pretty; }
.prose a { color: var(--accent); text-decoration: underline; text-decoration-thickness: 1px; text-underline-offset: 0.18em; text-decoration-color: color-mix(in srgb, var(--accent) 45%, transparent); transition: text-decoration-color 0.15s; }
.prose a:hover { text-decoration-color: currentColor; }
.prose strong { font-weight: 600; color: var(--ink); }
.prose h2 {
  margin: 3.75rem 0 1.25rem; padding-top: 1.5rem; border-top: 1px solid var(--line);
  font-family: var(--f-sans); font-weight: 700; font-size: clamp(1.55rem, 1.2rem + 1.2vw, 2.1rem); line-height: 1.12; letter-spacing: -0.025em;
  text-wrap: balance;
}
.num { display: block; margin-bottom: 0.7rem; font-family: var(--f-mono); font-weight: 500; font-size: 0.75rem; letter-spacing: 0.06em; color: var(--accent); }

.summary {
  position: relative; margin: 0 0 1.5rem; padding: 1.5rem 1.6rem; border-radius: 14px;
  background: var(--surface); border: 1px solid var(--line); box-shadow: var(--shadow);
}
.summary::before { content: ""; position: absolute; left: -1px; top: 1.4rem; bottom: 1.4rem; width: 3px; border-radius: 3px; background: var(--accent); }
.summary p { margin: 0; font-size: 1.04em; }
.milestone-intro { font-size: 1.04em; }

/* layers */
.layers { list-style: none; margin: 1.5rem 0 2rem; padding: 0; display: grid; gap: 0.75rem; }
@media (min-width: 40rem) { .layers { grid-template-columns: 1fr 1fr; } }
.layer { position: relative; padding: 1.25rem 1.3rem 1.3rem; border-radius: 14px; border: 1px solid var(--line); background: var(--surface); }
.layer p { margin: 0; font-size: 0.95em; line-height: 1.55; }
.layer .layer-tag { display: inline-block; margin-bottom: 0.85rem; padding: 0.2rem 0.55rem; border-radius: 6px; font-family: var(--f-mono); font-size: 0.68rem; letter-spacing: 0.06em; text-transform: uppercase; }
.layer-open { border-color: color-mix(in srgb, var(--open) 35%, var(--line)); }
.layer-open .layer-tag { background: var(--open-soft); color: var(--open); }
.layer-domain .layer-tag { background: var(--accent-soft); color: var(--accent); }

/* pipeline */
.pipeline {
  margin: 2rem 0 2.5rem; padding: 1.5rem 1.25rem 1.25rem;
  display: grid; grid-template-columns: minmax(0, 1fr) auto minmax(0, 1fr) auto minmax(0, 1fr); align-items: center; column-gap: 0.5rem; row-gap: 0.4rem;
  border-radius: 14px; border: 1px solid var(--line);
  background:
    linear-gradient(var(--grid) 1px, transparent 1px) 0 0 / 20px 20px,
    linear-gradient(90deg, var(--grid) 1px, transparent 1px) 0 0 / 20px 20px,
    var(--bg-2);
}
.stage { display: flex; flex-direction: column; gap: 0.3rem; padding: 0.9rem 0.85rem; border-radius: 10px; background: var(--surface); border: 1px solid var(--line-strong); min-width: 0; }
.stage-n { font-family: var(--f-mono); font-size: 0.68rem; color: var(--ink-soft); }
.stage-name { font-family: var(--f-sans); font-weight: 600; font-size: 0.98rem; letter-spacing: -0.01em; }
.stage-io { font-family: var(--f-mono); font-size: 0.68rem; color: var(--ink-soft); overflow-wrap: anywhere; }
.stage-later { border-style: dashed; background: transparent; }
.stage-later .stage-name { color: var(--ink-soft); }
.arrow { width: 1.4rem; height: 1px; background: var(--ink-soft); position: relative; }
.arrow::after { content: ""; position: absolute; right: -1px; top: -3.5px; border: 4px solid transparent; border-left: 6px solid var(--ink-soft); border-right: 0; }
.arrow-later { background: repeating-linear-gradient(90deg, var(--ink-soft) 0 3px, transparent 3px 6px); }
.bracket { grid-column: 1 / 4; grid-row: 2; display: flex; flex-direction: column; align-items: center; gap: 0.45rem; }
.bracket::before { content: ""; align-self: stretch; height: 0.6rem; border: 1.5px solid var(--accent); border-top: 0; border-radius: 0 0 8px 8px; }
.bracket span { font-family: var(--f-mono); font-size: 0.68rem; letter-spacing: 0.04em; color: var(--accent); white-space: nowrap; }
@media (max-width: 34rem) {
  .pipeline { grid-template-columns: auto minmax(0, 1fr); column-gap: 0.75rem; row-gap: 0.5rem; }
  .pipeline > :not(.bracket) { grid-column: 2; }
  .arrow { width: 1px; height: 1rem; justify-self: center; }
  .arrow::after { right: auto; top: auto; left: -3.5px; bottom: -1px; border: 4px solid transparent; border-top: 6px solid var(--ink-soft); border-bottom: 0; }
  .arrow-later { background: repeating-linear-gradient(180deg, var(--ink-soft) 0 3px, transparent 3px 6px); }
  .bracket { grid-column: 1; grid-row: 1 / 4; flex-direction: row-reverse; align-self: stretch; gap: 0.35rem; }
  .bracket::before { width: 0.6rem; height: auto; align-self: stretch; border: 1.5px solid var(--accent); border-right: 0; border-radius: 8px 0 0 8px; }
  .bracket span { writing-mode: vertical-rl; transform: rotate(180deg); align-self: center; }
}

/* reasons */
.reasons { list-style: none; counter-reset: r; margin: 1.5rem 0 2rem; padding: 0; display: grid; gap: 0.75rem; }
.reasons li { counter-increment: r; position: relative; padding: 1.15rem 1.3rem 1.2rem 3.6rem; border-radius: 14px; border: 1px solid var(--line); background: var(--surface); }
.reasons li::before {
  content: counter(r); position: absolute; left: 1.15rem; top: 1.15rem;
  width: 1.7rem; height: 1.7rem; display: grid; place-items: center; border-radius: 50%;
  font-family: var(--f-mono); font-size: 0.78rem; font-weight: 500; color: var(--accent); background: var(--accent-soft);
}
.reasons p { margin: 0; font-size: 0.95em; line-height: 1.55; }

.callout { margin: 2rem 0; padding: 1.5rem 1.6rem; border-radius: 14px; background: var(--ink); color: var(--bg); }
.callout p { margin: 0; font-size: 1.04em; }

/* roles */
.roles { list-style: none; margin: 1.5rem 0 2rem; padding: 0; display: grid; gap: 0.75rem; }
@media (min-width: 40rem) { .roles { grid-template-columns: 1fr 1fr; } }
.roles li { padding: 1.3rem; border-radius: 14px; border: 1px solid var(--line); background: var(--surface); transition: border-color 0.2s, transform 0.2s; }
.roles li:hover { border-color: color-mix(in srgb, var(--accent) 45%, var(--line)); }
.roles p { margin: 0; font-size: 0.95em; line-height: 1.55; }
.roles .role-sym { width: 2.4rem; height: 2.4rem; margin-bottom: 1rem; display: grid; place-items: center; border-radius: 10px; background: var(--accent-soft); color: var(--accent); font-family: var(--f-serif); font-size: 1.35rem; line-height: 1; }

/* contact */
.contact { margin-top: 3.75rem; }
.contact h2 { margin-top: 0; }
.contact-links { display: flex; flex-wrap: wrap; gap: 0.6rem; margin-top: 1.75rem; }
.btn {
  display: inline-flex; align-items: center; max-width: 100%; padding: 0.8rem 1.15rem; border-radius: 999px;
  font-family: var(--f-sans); font-weight: 600; font-size: 0.92rem; text-decoration: none !important; overflow-wrap: anywhere;
  border: 1px solid var(--line-strong); color: var(--ink) !important; transition: background 0.15s, color 0.15s, border-color 0.15s, transform 0.15s;
}
.btn:hover { border-color: var(--ink); transform: translateY(-1px); }
.btn-primary { background: var(--accent); border-color: var(--accent); color: var(--accent-ink) !important; }
.btn-primary:hover { background: var(--ink); border-color: var(--ink); color: var(--bg) !important; }

/* footer */
.foot { display: flex; justify-content: space-between; align-items: center; gap: 1rem; padding-block: 2.5rem 3rem; margin-top: 3rem; border-top: 1px solid var(--line); font-family: var(--f-mono); font-size: 0.75rem; color: var(--ink-soft); }
.foot a { text-decoration: none; }
.foot a:hover { color: var(--ink); }

@media print {
  .top, .progress, .toc, .hero-grid { display: none !important; }
  body { background: #fff; color: #000; }
  .callout { background: #f1f1f1; color: #000; }
}