/* ==========================================================================
   BB Systems — "The Drawing Set"
   A technical drawing-set / site-plan visual world: blueprint blue as the
   literal field colour (the client's requested trust-blue, made structural
   rather than decorative), warm drafting-paper neutrals, ink linework,
   numbered sheets, and authored axonometric diagrams standing in for
   photography that does not exist yet.
   ========================================================================== */

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

html { scroll-behavior: smooth; }

:root {
  /* Brand palette — blueprint blue as the dominant trust colour */
  --primary:      #1c3f6e;   /* blueprint field blue */
  --primary-mid:  #2f5c9c;
  --primary-dark: #0d1f38;   /* navy-black, never pure black */
  --primary-tint: #e8eef7;   /* pale blue wash for surfaces on the paper ground */

  /* Accent — the redline / revision-mark, used sparingly */
  --accent:       #b3452c;
  --accent-mid:   #d3624a;
  --accent-dark:  #8a3320;

  /* Neutrals — warm drafting paper, not flat grey */
  --bg:        #f6f2e9;
  --surface:   #fffdf8;
  --border:    #cdd3da;
  --border-blue: #b9c7dc;
  --text:      #14202f;
  --text-soft: #46536a;
  --text-muted:#5a6579;
  --text-on-blue: #eef2f9;
  --text-on-blue-soft: #b9c9e3;

  /* Typography */
  --font-display: 'Big Shoulders Display', sans-serif;
  --font-body:    'Archivo', sans-serif;
  --font-mono:    'JetBrains Mono', monospace;

  /* Spacing */
  --section-pad: clamp(60px, 8vw, 120px);
  --container:   1200px;
  --radius:      4px;
  --radius-lg:   8px;

  --ease: cubic-bezier(0.16, 1, 0.3, 1);
}

body {
  font-family: var(--font-body);
  color: var(--text);
  background: var(--bg);
  line-height: 1.75;
  -webkit-font-smoothing: antialiased;
}

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

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

ul { list-style: none; }

button { font-family: inherit; cursor: pointer; }

.container {
  max-width: var(--container);
  margin-inline: auto;
  padding-inline: clamp(1.25rem, 5vw, 2.5rem);
}

section { padding-block: var(--section-pad); }

/* ---- Typography scale ---- */

h1, h2, h3 {
  font-family: var(--font-display);
  font-weight: 700;
  letter-spacing: -0.01em;
  text-transform: uppercase;
}

h1 { font-size: clamp(2.8rem, 8vw, 6rem); line-height: 0.95; letter-spacing: -0.015em; }
h2 { font-size: clamp(1.9rem, 5vw, 3.2rem); line-height: 1; }
h3 { font-size: clamp(1.15rem, 2.4vw, 1.6rem); line-height: 1.1; }

p { font-size: clamp(0.98rem, 1.3vw, 1.08rem); line-height: 1.75; max-width: 66ch; }

.eyebrow-sheet {
  font-family: var(--font-mono);
  font-size: 0.72rem;
  letter-spacing: 0.12em;
  color: var(--text-muted);
  text-transform: uppercase;
}

.section-head {
  display: flex;
  flex-wrap: wrap;
  align-items: flex-end;
  justify-content: space-between;
  gap: 1.5rem;
  margin-bottom: clamp(2rem, 5vw, 3.5rem);
  padding-bottom: 1.25rem;
  border-bottom: 1px solid var(--border-blue);
}

.section-head h2 { max-width: 20ch; }
.section-head .sheet-meta { text-align: right; }

/* ---- Dimension-line motif (drafting furniture) ---- */

.dim-line {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  font-family: var(--font-mono);
  font-size: 0.7rem;
  letter-spacing: 0.08em;
  color: var(--text-muted);
}
.dim-line::before, .dim-line::after {
  content: '';
  flex: 1;
  height: 1px;
  background: var(--border-blue);
}
.dim-line--on-blue { color: var(--text-on-blue-soft); }
.dim-line--on-blue::before, .dim-line--on-blue::after { background: rgba(255,255,255,0.25); }

/* ---- Buttons ---- */

.btn {
  display: inline-flex;
  align-items: center;
  gap: 0.6rem;
  font-family: var(--font-body);
  font-weight: 700;
  font-size: 0.95rem;
  letter-spacing: 0.01em;
  padding: 0.95rem 1.9rem;
  border-radius: var(--radius);
  border: 1.5px solid transparent;
  transition: background 0.2s var(--ease), color 0.2s var(--ease), border-color 0.2s var(--ease), transform 0.2s var(--ease);
}

.btn-primary {
  background: var(--accent);
  color: #fff8f3;
}
.btn-primary:hover { background: var(--accent-dark); transform: translateY(-2px); }
.btn-primary:focus-visible { outline: 3px solid var(--accent-mid); outline-offset: 3px; }

.btn-ghost-on-blue {
  background: transparent;
  color: var(--text-on-blue);
  border-color: rgba(238,242,249,0.4);
}
.btn-ghost-on-blue:hover { background: rgba(238,242,249,0.1); border-color: var(--text-on-blue); }
.btn-ghost-on-blue:focus-visible { outline: 3px solid var(--text-on-blue); outline-offset: 3px; }

.btn-outline {
  background: transparent;
  color: var(--primary);
  border-color: var(--primary);
}
.btn-outline:hover { background: var(--primary); color: var(--text-on-blue); }
.btn-outline:focus-visible { outline: 3px solid var(--primary-mid); outline-offset: 3px; }

/* ==========================================================================
   Navigation — a persistent title-block strip
   ========================================================================== */

.site-nav {
  position: fixed;
  top: 0; left: 0; right: 0;
  z-index: 100;
  padding-block: 1.1rem;
  background: transparent;
  border-bottom: 1px solid transparent;
  transition: background 0.3s var(--ease), border-color 0.3s var(--ease);
}

.site-nav.is-scrolled {
  background: rgba(246, 242, 233, 0.94);
  backdrop-filter: blur(10px);
  border-bottom-color: var(--border-blue);
  padding-block: 0.7rem;
}

.nav-row {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
}

.nav-logo {
  display: flex;
  flex-direction: column;
  line-height: 1;
}
.nav-logo .mark {
  font-family: var(--font-display);
  font-weight: 700;
  font-size: 1.5rem;
  letter-spacing: -0.01em;
  color: var(--text-on-blue);
  transition: color 0.3s var(--ease);
}
.nav-logo .sub {
  font-family: var(--font-mono);
  font-size: 0.62rem;
  letter-spacing: 0.14em;
  color: var(--text-on-blue-soft);
  text-transform: uppercase;
  margin-top: 0.15rem;
  transition: color 0.3s var(--ease);
}
.site-nav.is-scrolled .nav-logo .mark { color: var(--primary); }
.site-nav.is-scrolled .nav-logo .sub { color: var(--text-muted); }

.nav-links {
  display: none;
  align-items: center;
  gap: clamp(1.2rem, 2vw, 2.2rem);
}
.nav-links a {
  font-family: var(--font-mono);
  font-size: 0.78rem;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  color: var(--text-on-blue-soft);
  padding-block: 0.3rem;
  border-bottom: 1px solid transparent;
  transition: color 0.2s var(--ease), border-color 0.2s var(--ease);
}
.nav-links a:hover, .nav-links a:focus-visible { color: var(--text-on-blue); border-color: var(--text-on-blue); }
.nav-links a[aria-current="page"] { color: var(--text-on-blue); border-color: var(--accent-mid); }
.site-nav.is-scrolled .nav-links a { color: var(--text-soft); }
.site-nav.is-scrolled .nav-links a:hover { color: var(--primary); border-color: var(--primary); }
.site-nav.is-scrolled .nav-links a[aria-current="page"] { color: var(--primary); border-color: var(--primary); }

.nav-cta {
  display: none;
}

.hamburger {
  display: flex;
  flex-direction: column;
  justify-content: center;
  gap: 5px;
  width: 40px;
  height: 40px;
  background: transparent;
  border: 1px solid rgba(238,242,249,0.4);
  border-radius: var(--radius);
  padding: 0;
  align-items: center;
  transition: border-color 0.2s var(--ease);
}
.site-nav.is-scrolled .hamburger { border-color: var(--border-blue); }
.hamburger span {
  width: 18px;
  height: 2px;
  background: var(--text-on-blue);
  transition: background 0.2s var(--ease), transform 0.25s var(--ease), opacity 0.2s var(--ease);
}
.site-nav.is-scrolled .hamburger span { background: var(--primary); }

.hamburger[aria-expanded="true"] span:nth-child(1) { transform: translateY(7px) rotate(45deg); }
.hamburger[aria-expanded="true"] span:nth-child(2) { opacity: 0; }
.hamburger[aria-expanded="true"] span:nth-child(3) { transform: translateY(-7px) rotate(-45deg); }

.mobile-menu {
  position: fixed;
  inset: 0;
  z-index: 99;
  background: var(--primary-dark);
  display: flex;
  flex-direction: column;
  justify-content: center;
  gap: 2rem;
  overflow-y: auto;
  padding: 6rem clamp(1.5rem, 8vw, 4rem) 2rem;
  transform: translateY(-100%);
  visibility: hidden;
  transition: transform 0.4s var(--ease), visibility 0s linear 0.4s;
}
.mobile-menu.is-open {
  transform: translateY(0);
  visibility: visible;
  transition: transform 0.4s var(--ease), visibility 0s linear 0s;
}
.mobile-menu a {
  font-family: var(--font-display);
  font-size: clamp(2rem, 9vw, 3rem);
  color: var(--text-on-blue);
  text-transform: uppercase;
  padding-block: 0.3rem;
  border-bottom: 1px solid rgba(238,242,249,0.15);
}
.mobile-menu .btn { margin-top: 1rem; align-self: flex-start; }

@media (min-width: 900px) {
  .nav-links { display: flex; }
  .nav-cta { display: inline-flex; }
  .hamburger { display: none; }
}

/* ==========================================================================
   Hero — the site plan
   ========================================================================== */

.hero {
  min-height: 100svh;
  display: flex;
  flex-direction: column;
  justify-content: flex-end;
  position: relative;
  background: var(--primary);
  background-image:
    linear-gradient(rgba(238,242,249,0.06) 1px, transparent 1px),
    linear-gradient(90deg, rgba(238,242,249,0.06) 1px, transparent 1px),
    radial-gradient(ellipse at 20% 0%, rgba(47,92,156,0.55), transparent 60%);
  background-size: 44px 44px, 44px 44px, 100% 100%;
  overflow: hidden;
  isolation: isolate;
}

.hero-plan {
  position: absolute;
  inset: 0;
  z-index: -1;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: clamp(1rem, 4vw, 3rem);
  padding-top: 6rem;
}

.hero-plan svg {
  width: min(100%, 1180px);
  height: auto;
  opacity: 0.9;
}

.hero-content {
  position: relative;
  padding-block: clamp(1.5rem, 5vw, 3rem);
}

.hero-inner {
  max-width: var(--container);
  margin-inline: auto;
  padding-inline: clamp(1.25rem, 5vw, 2.5rem);
  width: 100%;
}

.hero-tag {
  display: inline-flex;
  align-items: center;
  gap: 0.6rem;
  font-family: var(--font-mono);
  font-size: 0.75rem;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--text-on-blue-soft);
  border: 1px solid rgba(238,242,249,0.3);
  border-radius: 999px;
  padding: 0.4rem 1rem;
  margin-bottom: 1.5rem;
}
.hero-tag .dot { width: 6px; height: 6px; border-radius: 50%; background: var(--accent-mid); }

.hero h1 { color: var(--text-on-blue); max-width: 30ch; }
.hero h1 em { font-style: normal; color: var(--accent-mid); }

.hero-sub {
  color: var(--text-on-blue-soft);
  max-width: 46ch;
  margin-top: 1.25rem;
  font-size: clamp(1rem, 1.6vw, 1.2rem);
}

.hero-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 1rem;
  margin-top: 2.5rem;
}

.hero-scale {
  display: flex;
  gap: clamp(1.5rem, 4vw, 3rem);
  margin-top: clamp(1.5rem, 4vw, 2.5rem);
  padding-top: 1.5rem;
  border-top: 1px solid rgba(238,242,249,0.18);
  flex-wrap: wrap;
}
.hero-scale .zone {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  letter-spacing: 0.08em;
  color: var(--text-on-blue-soft);
  text-transform: uppercase;
}
.hero-scale .zone strong {
  display: block;
  font-family: var(--font-display);
  font-size: clamp(1.4rem, 2.6vw, 1.9rem);
  color: var(--text-on-blue);
  letter-spacing: -0.01em;
  margin-bottom: 0.2rem;
}

/* ==========================================================================
   Reveal animation
   ========================================================================== */

.reveal { opacity: 0; transform: translateY(28px); transition: opacity 0.7s var(--ease), transform 0.7s var(--ease); }
.reveal.visible { opacity: 1; transform: none; }
.reveal-delay-1.visible { transition-delay: 0.08s; }
.reveal-delay-2.visible { transition-delay: 0.16s; }
.reveal-delay-3.visible { transition-delay: 0.24s; }

@media (max-width: 480px) {
  .hero-content { padding-block: 1.25rem; }
  .hero-scale { margin-top: 1rem; padding-top: 1rem; gap: 1.25rem; }
  .hero-tag { margin-bottom: 1rem; }
}

@media (prefers-reduced-motion: reduce) {
  .reveal { opacity: 1; transform: none; transition: none; }
  html { scroll-behavior: auto; }
}

/* ==========================================================================
   Systems Schedule (services) — a parts schedule, not icon cards
   ========================================================================== */

.schedule-section { background: var(--bg); }

.schedule-list {
  border-top: 1px solid var(--border-blue);
}

.schedule-row {
  display: grid;
  grid-template-columns: 3.5rem 1fr;
  gap: 1.5rem;
  padding-block: clamp(1.75rem, 4vw, 2.75rem);
  border-bottom: 1px solid var(--border-blue);
  align-items: start;
}

.schedule-row .no {
  font-family: var(--font-mono);
  font-size: 0.9rem;
  color: var(--text-muted);
  padding-top: 0.3rem;
}

.schedule-row .diagram {
  width: clamp(96px, 12vw, 140px);
  flex-shrink: 0;
}
.schedule-row .diagram svg { width: 100%; height: auto; color: var(--primary); }

.schedule-row .body {
  display: grid;
  grid-template-columns: 1fr;
  gap: 1rem;
}

.schedule-row h3 { color: var(--text); margin-bottom: 0.35rem; }
.schedule-row p { color: var(--text-soft); }

.schedule-row .content-grid {
  display: grid;
  grid-template-columns: auto 1fr;
  gap: 1.5rem;
  align-items: start;
}

@media (min-width: 640px) {
  .schedule-row { grid-template-columns: 3.5rem auto 1fr; }
}

/* ==========================================================================
   About / Story
   ========================================================================== */

.about-section .container {
  display: grid;
  grid-template-columns: 1fr;
  gap: clamp(2.5rem, 6vw, 4rem);
  align-items: center;
}

.about-elevation {
  background: var(--surface);
  border: 1px solid var(--border-blue);
  border-radius: var(--radius-lg);
  padding: clamp(1.5rem, 4vw, 2.5rem);
  position: relative;
}
.about-elevation .sheet-label {
  display: flex;
  justify-content: space-between;
  font-family: var(--font-mono);
  font-size: 0.68rem;
  letter-spacing: 0.08em;
  color: var(--text-muted);
  text-transform: uppercase;
  margin-bottom: 1rem;
  padding-bottom: 0.75rem;
  border-bottom: 1px solid var(--border);
}
.about-elevation svg { width: 100%; height: auto; color: var(--primary); }

.about-copy .eyebrow-sheet { margin-bottom: 1rem; display: block; }
.about-copy h2 { margin-bottom: 1.25rem; }
.about-copy p + p { margin-top: 1rem; }
.about-copy .btn { margin-top: 2rem; }

@media (min-width: 900px) {
  .about-section .container { grid-template-columns: 0.9fr 1.1fr; }
  .about-section.reverse .container { grid-template-columns: 1.1fr 0.9fr; }
  .about-section.reverse .about-elevation { order: 2; }
}

/* ==========================================================================
   Systems Gallery — exploded diagrams
   ========================================================================== */

.gallery-section { background: var(--primary-dark); color: var(--text-on-blue); }
.gallery-section .section-head { border-bottom-color: rgba(238,242,249,0.18); }
.gallery-section .section-head h2 { color: var(--text-on-blue); }
.gallery-section .eyebrow-sheet { color: var(--text-on-blue-soft); }
.gallery-section p { color: var(--text-on-blue-soft); }

.gallery-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 1.5rem;
}

.gallery-card {
  background: rgba(238,242,249,0.04);
  border: 1px solid rgba(238,242,249,0.14);
  border-radius: var(--radius-lg);
  padding: clamp(1.5rem, 3vw, 2rem);
  transition: background 0.25s var(--ease), border-color 0.25s var(--ease), transform 0.25s var(--ease);
}
.gallery-card:hover { background: rgba(238,242,249,0.08); border-color: rgba(238,242,249,0.3); transform: translateY(-4px); }

.gallery-card .diagram-frame {
  background: var(--text-on-blue);
  border-radius: var(--radius);
  padding: 1.25rem;
  margin-bottom: 1.25rem;
}
.gallery-card .diagram-frame svg { width: 100%; height: auto; color: var(--primary-dark); }

.gallery-card .tag {
  font-family: var(--font-mono);
  font-size: 0.68rem;
  letter-spacing: 0.1em;
  color: var(--text-on-blue-soft);
  text-transform: uppercase;
  display: block;
  margin-bottom: 0.5rem;
}

.gallery-card h3 { color: var(--text-on-blue); margin-bottom: 0.5rem; }
.gallery-card p { font-size: 0.92rem; }

@media (min-width: 720px) {
  .gallery-grid { grid-template-columns: repeat(3, 1fr); }
}

.gallery-note {
  margin-top: 2.5rem;
  padding-top: 1.5rem;
  border-top: 1px solid rgba(238,242,249,0.14);
  font-family: var(--font-mono);
  font-size: 0.75rem;
  color: var(--text-on-blue-soft);
  letter-spacing: 0.02em;
}

/* ==========================================================================
   Process strip
   ========================================================================== */

.process-section { background: var(--surface); border-top: 1px solid var(--border-blue); border-bottom: 1px solid var(--border-blue); }

.process-list {
  display: grid;
  grid-template-columns: 1fr;
  gap: 0;
}

.process-item {
  display: grid;
  grid-template-columns: 3.5rem 1fr;
  gap: 1.5rem;
  padding-block: 1.75rem;
  border-bottom: 1px dashed var(--border-blue);
}
.process-item:last-child { border-bottom: none; }
.process-item .no { font-family: var(--font-mono); color: var(--primary); font-size: 0.9rem; padding-top: 0.2rem; }
.process-item h3 { margin-bottom: 0.4rem; }
.process-item p { color: var(--text-soft); font-size: 0.95rem; }

@media (min-width: 720px) {
  .process-list { grid-template-columns: repeat(4, 1fr); gap: 1.5rem; }
  .process-item { grid-template-columns: 1fr; border-bottom: none; padding-block: 0; }
  .process-item .no { padding-top: 0; border-top: 2px solid var(--primary); padding-top: 0.75rem; }
}

/* ==========================================================================
   Contact — request form styled as an enquiry sheet
   ========================================================================== */

.contact-section { background: var(--bg); }

.contact-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: clamp(2rem, 5vw, 3rem);
}

.contact-info { display: flex; flex-direction: column; gap: 1.75rem; }

.contact-info .info-row {
  display: flex;
  gap: 1rem;
  align-items: flex-start;
  padding-bottom: 1.5rem;
  border-bottom: 1px solid var(--border-blue);
}
.contact-info .info-row:last-child { border-bottom: none; }

.contact-info .icon {
  width: 2.4rem;
  height: 2.4rem;
  border: 1px solid var(--border-blue);
  border-radius: var(--radius);
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--primary);
  flex-shrink: 0;
}
.contact-info .icon svg { width: 1.15rem; height: 1.15rem; }

.contact-info .label {
  font-family: var(--font-mono);
  font-size: 0.68rem;
  letter-spacing: 0.1em;
  color: var(--text-muted);
  text-transform: uppercase;
  margin-bottom: 0.25rem;
}
.contact-info .value { font-weight: 600; }
.contact-info .value a:hover { color: var(--primary); }

.contact-form {
  background: var(--surface);
  border: 1px solid var(--border-blue);
  border-radius: var(--radius-lg);
  padding: clamp(1.5rem, 4vw, 2.5rem);
}

.form-sheet-head {
  display: flex;
  justify-content: space-between;
  align-items: baseline;
  margin-bottom: 1.75rem;
  padding-bottom: 1.25rem;
  border-bottom: 1px solid var(--border);
  flex-wrap: wrap;
  gap: 0.5rem;
}

.form-row { margin-bottom: 1.25rem; }
.form-row-split { display: grid; grid-template-columns: 1fr; gap: 1.25rem; }
@media (min-width: 560px) { .form-row-split { grid-template-columns: 1fr 1fr; } }

.form-row label {
  display: block;
  font-family: var(--font-mono);
  font-size: 0.7rem;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--text-muted);
  margin-bottom: 0.5rem;
}

.form-row input, .form-row textarea {
  width: 100%;
  font-family: var(--font-body);
  font-size: 1rem;
  color: var(--text);
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 0.85rem 1rem;
  transition: border-color 0.2s var(--ease), box-shadow 0.2s var(--ease);
}
.form-row input:focus, .form-row textarea:focus {
  outline: none;
  border-color: var(--primary);
  box-shadow: 0 0 0 3px var(--primary-tint);
}
.form-row textarea { resize: vertical; min-height: 120px; }

.form-note {
  font-size: 0.82rem;
  color: var(--text-muted);
  margin-top: 1rem;
  max-width: none;
}

.form-success {
  display: none;
  text-align: center;
  padding: 2.5rem 1rem;
}
.form-success.is-visible { display: block; }
.form-success .stamp {
  display: inline-flex;
  align-items: center;
  gap: 0.6rem;
  border: 2px solid var(--accent);
  color: var(--accent-dark);
  font-family: var(--font-display);
  text-transform: uppercase;
  letter-spacing: 0.05em;
  padding: 0.6rem 1.4rem;
  border-radius: var(--radius);
  transform: rotate(-2deg);
  margin-bottom: 1.25rem;
}
.form-success p { margin-inline: auto; }

@media (min-width: 960px) {
  .contact-grid { grid-template-columns: 0.85fr 1.15fr; }
}

/* ==========================================================================
   Page Header — subpage "sheet" banner (Systems / About / Range / Process / Contact)
   ========================================================================== */

.page-header {
  position: relative;
  overflow: hidden;
  background: var(--primary);
  background-image:
    linear-gradient(rgba(238,242,249,0.06) 1px, transparent 1px),
    linear-gradient(90deg, rgba(238,242,249,0.06) 1px, transparent 1px);
  background-size: 44px 44px;
  padding-block: clamp(7rem, 16vw, 9.5rem) clamp(3rem, 6vw, 4.5rem);
}

.page-header .container { position: relative; z-index: 1; }
.page-header .hero-tag { margin-bottom: 1.25rem; }

.page-title {
  color: var(--text-on-blue);
  font-family: var(--font-display);
  font-weight: 700;
  text-transform: uppercase;
  font-size: clamp(2.2rem, 6vw, 3.6rem);
  line-height: 1;
  max-width: 20ch;
}

.page-sub {
  color: var(--text-on-blue-soft);
  max-width: 56ch;
  margin-top: 1.1rem;
  font-size: clamp(1rem, 1.5vw, 1.15rem);
}

/* ==========================================================================
   Sheet Nav — prev/next between pages, echoing a drawing set's sheet index
   ========================================================================== */

.sheet-nav {
  border-top: 1px solid var(--border-blue);
  background: var(--surface);
}

.sheet-nav .container {
  display: flex;
  justify-content: space-between;
  gap: 1.5rem;
  flex-wrap: wrap;
  padding-block: clamp(1.75rem, 4vw, 2.5rem);
}

.sheet-nav a {
  display: flex;
  flex-direction: column;
  gap: 0.35rem;
  max-width: 26ch;
  transition: color 0.2s var(--ease);
}
.sheet-nav a:last-child { text-align: right; align-items: flex-end; margin-left: auto; }
.sheet-nav .dir {
  font-family: var(--font-mono);
  font-size: 0.68rem;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--text-muted);
}
.sheet-nav .title {
  font-family: var(--font-display);
  font-size: clamp(1.1rem, 2vw, 1.4rem);
  text-transform: uppercase;
  color: var(--text);
}
.sheet-nav a:hover .title { color: var(--primary); }

/* ==========================================================================
   Home teasers — compact links out to each sheet's dedicated page
   ========================================================================== */

.teaser-section { background: var(--bg); }

.teaser-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 1.25rem;
  margin-top: 2rem;
}

.teaser-card {
  display: flex;
  gap: 1.25rem;
  align-items: flex-start;
  padding: 1.5rem;
  background: var(--surface);
  border: 1px solid var(--border-blue);
  border-radius: var(--radius-lg);
  transition: border-color 0.2s var(--ease), transform 0.2s var(--ease);
}
.teaser-card:hover { border-color: var(--primary); transform: translateY(-3px); }
.teaser-card .diagram { width: 56px; flex-shrink: 0; }
.teaser-card .diagram svg { width: 100%; height: auto; color: var(--primary); }
.teaser-card h3 { margin-bottom: 0.35rem; }
.teaser-card p { color: var(--text-soft); font-size: 0.92rem; }
.teaser-card .more {
  display: inline-block;
  margin-top: 0.6rem;
  font-family: var(--font-mono);
  font-size: 0.72rem;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  color: var(--primary);
}

@media (min-width: 720px) {
  .teaser-grid { grid-template-columns: repeat(3, 1fr); }
}

.teaser-more-link { display: inline-flex; margin-top: 2rem; }

.about-teaser-band { background: var(--primary-dark); color: var(--text-on-blue); text-align: center; }
.about-teaser-band .container { max-width: 700px; }
.about-teaser-band h2 { color: var(--text-on-blue); margin-bottom: 1rem; }
.about-teaser-band p { color: var(--text-on-blue-soft); margin-inline: auto; }
.about-teaser-band .eyebrow-sheet { color: var(--text-on-blue-soft); }
.about-teaser-band .btn { margin-top: 1.5rem; }

.cta-band { background: var(--surface); border-top: 1px solid var(--border-blue); text-align: center; }
.cta-band .container { display: flex; flex-direction: column; align-items: center; gap: 1.25rem; }
.cta-band h2 { max-width: 18ch; }
.cta-band p { max-width: 50ch; }
.cta-band .actions { display: flex; gap: 1rem; flex-wrap: wrap; justify-content: center; margin-top: 0.5rem; }

/* ==========================================================================
   Footer
   ========================================================================== */

.site-footer {
  background: var(--primary-dark);
  color: var(--text-on-blue-soft);
  padding-block: clamp(3rem, 6vw, 4.5rem) 2rem;
}

.footer-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 2.5rem;
  padding-bottom: 2.5rem;
  border-bottom: 1px solid rgba(238,242,249,0.14);
}

.footer-brand .mark {
  font-family: var(--font-display);
  font-size: 1.6rem;
  color: var(--text-on-blue);
  text-transform: uppercase;
}
.footer-brand p { color: var(--text-on-blue-soft); margin-top: 1rem; font-size: 0.92rem; max-width: 34ch; }

.footer-col h4 {
  font-family: var(--font-mono);
  font-size: 0.72rem;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--text-on-blue);
  margin-bottom: 1rem;
}
.footer-col ul { display: flex; flex-direction: column; gap: 0.65rem; }
.footer-col a { font-size: 0.92rem; transition: color 0.2s var(--ease); }
.footer-col a:hover { color: var(--text-on-blue); }

.footer-bottom {
  display: flex;
  flex-wrap: wrap;
  justify-content: space-between;
  gap: 1rem;
  padding-top: 1.75rem;
  font-size: 0.82rem;
  color: var(--text-on-blue-soft);
}
.footer-bottom a:hover { color: var(--text-on-blue); }

@media (min-width: 720px) {
  .footer-grid { grid-template-columns: 1.4fr 1fr 1fr; }
}

/* ==========================================================================
   Focus visibility (global)
   ========================================================================== */

a:focus-visible, button:focus-visible {
  outline: 3px solid var(--primary-mid);
  outline-offset: 2px;
}