/* ============================================================
   COPSER CONSULTANCY — shared stylesheet
   Design system: "The Engineering Dossier"
   No frameworks. No webfonts. Hand-rolled.
   ============================================================ */

/* ---------- Tokens ---------- */
:root {
  --bg:        #141311;
  --bg-raised: #1b1a17;
  --bg-inset:  #0f0e0c;
  --ink:       #ece7dc;
  --ink-dim:   #9b9488;
  --ink-faint: #6d675d;
  --hairline:  rgba(236, 231, 220, 0.14);
  --hairline-soft: rgba(236, 231, 220, 0.07);
  --accent:      #d9a441;
  --accent-dim:  rgba(217, 164, 65, 0.16);
  --accent-text: #e4b45c;
  --ok:          #8fae8b;

  --font-sans: "Avenir Next", "Helvetica Neue", -apple-system, BlinkMacSystemFont,
               "Segoe UI", Roboto, Arial, sans-serif;
  --font-mono: ui-monospace, "SF Mono", "Cascadia Code", "JetBrains Mono",
               Menlo, Consolas, "Liberation Mono", monospace;

  --max: 1180px;
  --pad: clamp(1.25rem, 4vw, 2.5rem);
  --ease: cubic-bezier(0.22, 1, 0.36, 1);
}

/* ---------- Reset / base ---------- */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }

html {
  scroll-behavior: smooth;
  color-scheme: dark;
}

body {
  background: var(--bg);
  color: var(--ink);
  font-family: var(--font-sans);
  font-size: 1.0625rem;
  line-height: 1.65;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
  min-height: 100vh;
  position: relative;
}

/* Faint blueprint column grid across the whole document */
body::before {
  content: "";
  position: fixed;
  inset: 0;
  pointer-events: none;
  z-index: 0;
  background-image: repeating-linear-gradient(
    90deg,
    var(--hairline-soft) 0,
    var(--hairline-soft) 1px,
    transparent 1px,
    transparent 140px
  );
  opacity: 0.5;
}

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

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

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

/* ---------- Type utilities ---------- */
.mono {
  font-family: var(--font-mono);
  font-size: 0.6875rem;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--ink-dim);
}

.mono-accent { color: var(--accent-text); }

h1, h2, h3 {
  font-weight: 600;
  letter-spacing: -0.025em;
  line-height: 1.08;
  text-wrap: balance;
}

.display {
  font-size: clamp(2.5rem, 6.4vw, 4.75rem);
  letter-spacing: -0.035em;
  line-height: 1.02;
}

.lede {
  font-size: clamp(1.125rem, 2vw, 1.3125rem);
  line-height: 1.6;
  color: var(--ink-dim);
  max-width: 38em;
}

.lede strong, .body-copy strong { color: var(--ink); font-weight: 600; }

.body-copy { color: var(--ink-dim); max-width: 42em; }
.body-copy + .body-copy { margin-top: 1em; }

/* Inline text links */
.tlink {
  color: var(--ink);
  border-bottom: 1px solid var(--accent);
  padding-bottom: 1px;
  transition: color 0.25s var(--ease), border-color 0.25s var(--ease);
}
.tlink:hover { color: var(--accent-text); border-color: var(--accent-text); }

/* ---------- Layout shells ---------- */
.wrap {
  max-width: var(--max);
  margin-inline: auto;
  padding-inline: var(--pad);
  position: relative;
  z-index: 1;
}

.sec {
  padding-block: clamp(4rem, 9vw, 7.5rem);
  border-top: 1px solid var(--hairline-soft);
  position: relative;
}
.sec:first-of-type { border-top: 0; }

/* Section header row: mono label — rule — revision mark */
.sec-head {
  display: flex;
  align-items: baseline;
  gap: 1.25rem;
  margin-bottom: clamp(2.25rem, 5vw, 3.75rem);
}
.sec-head .rule {
  flex: 1;
  height: 1px;
  background: var(--hairline);
  align-self: center;
}
.sec-head .rev { color: var(--ink-faint); }

/* Registration ticks — corner "+" marks on framed blocks */
.ticks { position: relative; }
/* The tick-b helper must not occupy a grid/flex cell */
.ticks > .tick-b { position: absolute; inset: 0; pointer-events: none; }
.ticks::before, .ticks::after,
.ticks > .tick-b::before, .ticks > .tick-b::after {
  content: "+";
  position: absolute;
  font-family: var(--font-mono);
  font-size: 0.8125rem;
  line-height: 1;
  color: var(--ink-faint);
  pointer-events: none;
}
.ticks::before { top: -0.4em; left: -0.25em; }
.ticks::after  { top: -0.4em; right: -0.25em; }
.ticks > .tick-b::before { bottom: -0.4em; left: -0.25em; }
.ticks > .tick-b::after  { bottom: -0.4em; right: -0.25em; }

/* ---------- Top bar ---------- */
.topbar {
  position: fixed;
  top: 0; left: 0; right: 0;
  z-index: 50;
  background: color-mix(in srgb, var(--bg) 82%, transparent);
  -webkit-backdrop-filter: blur(12px);
  backdrop-filter: blur(12px);
  border-bottom: 1px solid transparent;
  transition: border-color 0.35s var(--ease);
}
.topbar.scrolled { border-bottom-color: var(--hairline); }

.topbar-inner {
  max-width: var(--max);
  margin-inline: auto;
  padding: 0 var(--pad);
  height: 4.25rem;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 2rem;
}

.wordmark { display: flex; align-items: baseline; gap: 0.6rem; }
.wordmark-main {
  font-weight: 700;
  font-size: 1.1875rem;
  letter-spacing: 0.02em;
  text-transform: uppercase;
}
.wordmark-sub {
  font-family: var(--font-mono);
  font-size: 0.625rem;
  letter-spacing: 0.22em;
  text-transform: uppercase;
  color: var(--ink-dim);
}

.nav { display: flex; align-items: center; gap: clamp(1.25rem, 3vw, 2.5rem); }

.nav a {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--ink-dim);
  display: inline-flex;
  align-items: baseline;
  gap: 0.45em;
  padding-block: 0.4em;
  position: relative;
  transition: color 0.25s var(--ease);
}
.nav a .nav-num { color: var(--ink-faint); font-size: 0.875em; transition: color 0.25s var(--ease); }
.nav a::after {
  content: "";
  position: absolute;
  left: 0; bottom: 0;
  width: 100%;
  height: 1px;
  background: var(--accent);
  transform: scaleX(0);
  transform-origin: left;
  transition: transform 0.35s var(--ease);
}
.nav a:hover { color: var(--ink); }
.nav a:hover::after { transform: scaleX(1); }
.nav a[aria-current="page"] { color: var(--ink); }
.nav a[aria-current="page"] .nav-num { color: var(--accent-text); }
.nav a[aria-current="page"]::after { transform: scaleX(1); }

/* Mobile menu button */
.menu-btn {
  display: none;
  background: none;
  border: 1px solid var(--hairline);
  width: 2.75rem; height: 2.75rem;
  cursor: pointer;
  position: relative;
  z-index: 60;
}
.menu-btn span {
  position: absolute;
  left: 25%; width: 50%; height: 1px;
  background: var(--ink);
  transition: transform 0.3s var(--ease), top 0.3s var(--ease);
}
.menu-btn span:nth-child(1) { top: calc(50% - 4px); }
.menu-btn span:nth-child(2) { top: calc(50% + 3px); }
.menu-btn[aria-expanded="true"] span:nth-child(1) { top: 50%; transform: rotate(45deg); }
.menu-btn[aria-expanded="true"] span:nth-child(2) { top: 50%; transform: rotate(-45deg); }

/* Push page content below fixed bar */
main { padding-top: 4.25rem; position: relative; z-index: 1; }

/* ---------- Buttons: bracket motif ---------- */
.btn {
  display: inline-flex;
  align-items: center;
  gap: 0.75em;
  font-family: var(--font-mono);
  font-size: 0.75rem;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--ink);
  padding: 0.95em 1.5em;
  border: 1px solid var(--hairline);
  background: transparent;
  cursor: pointer;
  position: relative;
  transition: border-color 0.3s var(--ease), background 0.3s var(--ease), color 0.3s var(--ease);
}
.btn::before, .btn::after {
  font-family: var(--font-mono);
  color: var(--accent-text);
  transition: transform 0.3s var(--ease);
}
.btn::before { content: "["; }
.btn::after  { content: "]"; }
.btn:hover::before { transform: translateX(-4px); }
.btn:hover::after  { transform: translateX(4px); }
.btn:hover { border-color: var(--accent); }

.btn-solid {
  background: var(--accent);
  border-color: var(--accent);
  color: var(--bg);
}
.btn-solid::before, .btn-solid::after { color: var(--bg); }
.btn-solid:hover { background: var(--accent-text); border-color: var(--accent-text); }

/* ---------- Hero (index) ---------- */
.hero {
  min-height: calc(92vh - 4.25rem);
  display: flex;
  flex-direction: column;
  justify-content: center;
  padding-block: clamp(4rem, 8vw, 6rem);
  position: relative;
}

.hero-topline {
  display: flex;
  align-items: center;
  gap: 1rem;
  margin-bottom: clamp(1.75rem, 4vw, 2.75rem);
}
.hero-topline .rule { flex: 1; max-width: 140px; height: 1px; background: var(--hairline); }

.hero h1 { max-width: 12.5em; }

.hero .lede { margin-top: clamp(1.5rem, 3vw, 2.25rem); }

.hero-cta {
  display: flex;
  flex-wrap: wrap;
  gap: 1rem;
  margin-top: clamp(2rem, 4vw, 3rem);
}

/* Hero spec block — key/value dossier card */
.spec {
  margin-top: clamp(3rem, 6vw, 4.5rem);
  border: 1px solid var(--hairline);
  background: color-mix(in srgb, var(--bg-raised) 65%, transparent);
  display: grid;
  grid-template-columns: repeat(3, 1fr);
}
.spec-item {
  padding: 1.25rem 1.5rem;
  border-left: 1px solid var(--hairline-soft);
}
.spec-item:first-child { border-left: 0; }
.spec-item dt { margin-bottom: 0.5rem; }
.spec-item dd {
  font-size: 0.9375rem;
  color: var(--ink);
  line-height: 1.5;
}

/* ---------- Ledger rows (replaces "cards") ---------- */
.ledger { border-top: 1px solid var(--hairline); }

.ledger-row {
  display: grid;
  grid-template-columns: 4.5rem 1fr 1.4fr auto;
  gap: 1.5rem;
  align-items: baseline;
  padding: 1.6rem 0.75rem;
  border-bottom: 1px solid var(--hairline);
  position: relative;
  transition: background 0.3s var(--ease);
}
a.ledger-row:hover { background: var(--bg-raised); }

.ledger-num {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  letter-spacing: 0.1em;
  color: var(--ink-faint);
  transition: color 0.3s var(--ease);
}
a.ledger-row:hover .ledger-num { color: var(--accent-text); }

.ledger-title {
  font-size: 1.1875rem;
  font-weight: 600;
  letter-spacing: -0.015em;
}

.ledger-desc {
  color: var(--ink-dim);
  font-size: 0.9375rem;
  line-height: 1.55;
}

.ledger-arrow {
  font-family: var(--font-mono);
  color: var(--ink-faint);
  transition: transform 0.3s var(--ease), color 0.3s var(--ease);
}
a.ledger-row:hover .ledger-arrow { transform: translateX(6px); color: var(--accent-text); }

/* ---------- Stack index strip ---------- */
.stack-strip {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem 0;
  font-family: var(--font-mono);
  font-size: 0.75rem;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--ink-dim);
}
.stack-strip span { white-space: nowrap; }
.stack-strip span::after {
  content: "/";
  margin-inline: 0.9em;
  color: var(--ink-faint);
}
.stack-strip span:last-child::after { content: ""; margin: 0; }

/* ---------- Principle / feature grid ---------- */
.grid-2, .grid-3 {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 1px;
  background: var(--hairline-soft);
  border: 1px solid var(--hairline-soft);
}
.grid-3 { grid-template-columns: repeat(3, 1fr); }
.grid-2 > *, .grid-3 > * { background: var(--bg); padding: 2rem; }

.cell-label { margin-bottom: 0.9rem; display: block; }
.cell-title {
  font-size: 1.1875rem;
  margin-bottom: 0.6rem;
}
.cell-body { color: var(--ink-dim); font-size: 0.9375rem; }

/* ---------- Doc header (interior pages) ---------- */
.doc-head {
  padding-block: clamp(3.5rem, 8vw, 6rem) clamp(2.5rem, 6vw, 4rem);
}
.doc-head .doc-meta {
  display: flex;
  align-items: center;
  gap: 1rem;
  margin-bottom: clamp(1.5rem, 3vw, 2.25rem);
}
.doc-head .doc-meta .rule { flex: 1; max-width: 140px; height: 1px; background: var(--hairline); }
.doc-head h1 {
  font-size: clamp(2.25rem, 5.4vw, 3.9rem);
  letter-spacing: -0.03em;
  max-width: 14em;
}
.doc-head .lede { margin-top: clamp(1.25rem, 2.5vw, 2rem); }

/* ---------- Service dossier entries ---------- */
.svc {
  display: grid;
  grid-template-columns: 8rem 1fr;
  gap: clamp(1.5rem, 4vw, 3.5rem);
  padding-block: clamp(2.5rem, 5vw, 3.75rem);
  border-top: 1px solid var(--hairline);
}
.svc-id {
  font-family: var(--font-mono);
  font-size: 0.8125rem;
  letter-spacing: 0.12em;
  color: var(--accent-text);
}
.svc h2 { font-size: clamp(1.375rem, 2.6vw, 1.75rem); margin-bottom: 0.9rem; }
.svc .body-copy { max-width: 40em; }

.svc-deliverables {
  margin-top: 1.5rem;
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
}
.chip {
  font-family: var(--font-mono);
  font-size: 0.6875rem;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--ink-dim);
  border: 1px solid var(--hairline);
  padding: 0.45em 0.9em;
  transition: border-color 0.3s var(--ease), color 0.3s var(--ease);
}
.svc:hover .chip { border-color: var(--hairline); }
.chip:hover { border-color: var(--accent); color: var(--ink); }

/* ---------- Phase list (approach) ---------- */
.phase {
  display: grid;
  grid-template-columns: 8rem 1fr;
  gap: clamp(1.5rem, 4vw, 3.5rem);
  padding-block: clamp(2.25rem, 5vw, 3.5rem);
  border-top: 1px solid var(--hairline);
  position: relative;
}
.phase-num {
  font-family: var(--font-mono);
  font-size: clamp(1.5rem, 3vw, 2rem);
  color: var(--ink-faint);
  line-height: 1;
  transition: color 0.4s var(--ease);
}
.phase.in .phase-num, .phase:hover .phase-num { color: var(--accent-text); }
.phase h2 { font-size: clamp(1.375rem, 2.6vw, 1.75rem); margin-bottom: 0.9rem; }
.phase .phase-kicker { display: block; margin-bottom: 0.75rem; }

/* ---------- Definition table (about / record) ---------- */
.record {
  border: 1px solid var(--hairline);
}
.record-row {
  display: grid;
  grid-template-columns: 11rem 1fr;
  border-top: 1px solid var(--hairline-soft);
}
.record-row:first-child { border-top: 0; }
.record-row dt {
  padding: 1.1rem 1.5rem;
  border-right: 1px solid var(--hairline-soft);
  align-self: stretch;
  display: flex;
  align-items: center;
}
.record-row dd {
  padding: 1.1rem 1.5rem;
  color: var(--ink);
  font-size: 0.9375rem;
  line-height: 1.55;
}
.record-row dd .dim { color: var(--ink-dim); }

/* ---------- Quote / callout ---------- */
.callout {
  border-left: 2px solid var(--accent);
  padding: 0.4rem 0 0.4rem 1.75rem;
  max-width: 36em;
  font-size: clamp(1.1875rem, 2.2vw, 1.4375rem);
  line-height: 1.5;
  letter-spacing: -0.01em;
}
.callout .mono { display: block; margin-top: 1.1rem; }

/* ---------- CTA band ---------- */
.cta-band {
  border: 1px solid var(--hairline);
  background: var(--bg-raised);
  padding: clamp(2.5rem, 6vw, 4.5rem);
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 2rem;
}
.cta-band h2 {
  font-size: clamp(1.5rem, 3.2vw, 2.25rem);
  max-width: 16em;
}
.cta-band .mono { display: block; margin-bottom: 0.9rem; }

/* ---------- Contact form ---------- */
.contact-grid {
  display: grid;
  grid-template-columns: 1.2fr 1fr;
  gap: clamp(2.5rem, 6vw, 5rem);
  align-items: start;
}

.field { margin-bottom: 1.75rem; }
.field label { display: block; margin-bottom: 0.6rem; }
.field input, .field textarea {
  width: 100%;
  background: var(--bg-inset);
  border: 1px solid var(--hairline);
  color: var(--ink);
  font-family: var(--font-sans);
  font-size: 1rem;
  padding: 0.9em 1em;
  transition: border-color 0.3s var(--ease);
  border-radius: 0;
  -webkit-appearance: none;
}
.field textarea { min-height: 10.5rem; resize: vertical; line-height: 1.6; }
.field input:focus, .field textarea:focus {
  outline: none;
  border-color: var(--accent);
}
.field input::placeholder, .field textarea::placeholder { color: var(--ink-faint); }

.form-note {
  margin-top: 1.25rem;
  font-size: 0.8125rem;
  color: var(--ink-faint);
  max-width: 34em;
}

/* Pre-flight checklist */
.preflight { border: 1px solid var(--hairline); }
.preflight-head {
  padding: 1rem 1.5rem;
  border-bottom: 1px solid var(--hairline-soft);
}
.preflight ul { list-style: none; }
.preflight li {
  padding: 1rem 1.5rem;
  border-top: 1px solid var(--hairline-soft);
  display: flex;
  gap: 0.9rem;
  font-size: 0.9375rem;
  color: var(--ink-dim);
}
.preflight li:first-child { border-top: 0; }
.preflight li::before {
  content: "○";
  font-family: var(--font-mono);
  color: var(--accent-text);
  flex-shrink: 0;
}

.direct-line { margin-top: 2rem; }
.direct-line a {
  font-family: var(--font-mono);
  font-size: 0.9375rem;
  letter-spacing: 0.04em;
  color: var(--ink);
  border-bottom: 1px solid var(--accent);
  transition: color 0.25s var(--ease);
}
.direct-line a:hover { color: var(--accent-text); }

/* ---------- Footer ---------- */
.footer {
  border-top: 1px solid var(--hairline);
  margin-top: clamp(4rem, 9vw, 7rem);
  position: relative;
  overflow: hidden;
  z-index: 1;
  background: var(--bg);
}

.footer-grid {
  max-width: var(--max);
  margin-inline: auto;
  padding: clamp(3rem, 6vw, 4.5rem) var(--pad) clamp(2rem, 4vw, 3rem);
  display: grid;
  grid-template-columns: 2fr 1fr 1fr 1fr;
  gap: 2.5rem;
  position: relative;
  z-index: 1;
}

.footer h3 { margin-bottom: 1.1rem; }
.footer-col a {
  display: block;
  font-size: 0.9375rem;
  color: var(--ink-dim);
  padding-block: 0.3rem;
  transition: color 0.25s var(--ease);
}
.footer-col a:hover { color: var(--accent-text); }

.footer-tag {
  color: var(--ink-dim);
  font-size: 0.9375rem;
  max-width: 24em;
  margin-top: 0.9rem;
}

.footer-base {
  max-width: var(--max);
  margin-inline: auto;
  padding: 1.5rem var(--pad) 2rem;
  display: flex;
  flex-wrap: wrap;
  justify-content: space-between;
  align-items: center;
  gap: 1rem;
  border-top: 1px solid var(--hairline-soft);
  position: relative;
  z-index: 1;
}

/* Giant ghost wordmark behind footer */
.footer-mark {
  position: absolute;
  bottom: -0.28em;
  left: 50%;
  transform: translateX(-50%);
  font-weight: 800;
  font-size: clamp(6rem, 22vw, 17rem);
  letter-spacing: 0.02em;
  line-height: 1;
  color: transparent;
  -webkit-text-stroke: 1px var(--hairline-soft);
  user-select: none;
  pointer-events: none;
  white-space: nowrap;
  z-index: 0;
}

/* ---------- Reveal on scroll ---------- */
[data-reveal] {
  opacity: 0;
  transform: translateY(16px);
  transition: opacity 0.7s var(--ease), transform 0.7s var(--ease);
}
[data-reveal].in {
  opacity: 1;
  transform: none;
}

/* ---------- Reduced motion ---------- */
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  [data-reveal] { opacity: 1; transform: none; transition: none; }
  *, *::before, *::after { transition-duration: 0.01ms !important; animation-duration: 0.01ms !important; }
}

/* ---------- Responsive ---------- */
@media (max-width: 900px) {
  .ledger-row {
    grid-template-columns: 3rem 1fr auto;
    gap: 1rem;
  }
  .ledger-desc { grid-column: 2 / 3; grid-row: 2; }
  .ledger-arrow { grid-row: 1; }

  .svc, .phase { grid-template-columns: 1fr; gap: 1rem; }
  .spec { grid-template-columns: 1fr; }
  .spec-item { border-left: 0; border-top: 1px solid var(--hairline-soft); }
  .spec-item:first-child { border-top: 0; }

  .grid-2, .grid-3 { grid-template-columns: 1fr; }
  .contact-grid { grid-template-columns: 1fr; }
  .footer-grid { grid-template-columns: 1fr 1fr; }
  .record-row { grid-template-columns: 1fr; }
  .record-row dt { border-right: 0; border-bottom: 1px solid var(--hairline-soft); padding-bottom: 0.75rem; }
}

@media (max-width: 720px) {
  .menu-btn { display: block; }

  /* Note: .topbar's backdrop-filter makes it the containing block for this
     fixed overlay, so use explicit top/height instead of inset. */
  .nav {
    position: fixed;
    top: 0; left: 0; right: 0;
    height: 100vh;
    background: var(--bg);
    flex-direction: column;
    justify-content: center;
    align-items: flex-start;
    padding: var(--pad);
    gap: 0;
    transform: translateY(-100%);
    visibility: hidden;
    transition: transform 0.45s var(--ease), visibility 0s linear 0.45s;
    z-index: 55;
  }
  .nav.open {
    transform: translateY(0);
    visibility: visible;
    transition: transform 0.45s var(--ease);
  }
  .nav a {
    font-size: 1.25rem;
    letter-spacing: 0.08em;
    padding: 1.1rem 0;
    width: 100%;
    border-bottom: 1px solid var(--hairline-soft);
  }
  .nav a::after { display: none; }

  .footer-grid { grid-template-columns: 1fr; gap: 2rem; }
  .cta-band { padding: 2rem 1.5rem; }
}