/* ═══════════════════════════════════════════════════════════════════
   BeaconLock — Website Stylesheet
   Aerospace · Optical · Engineering identity
   ═══════════════════════════════════════════════════════════════════ */

/* ── Tokens ─────────────────────────────────────────────────────── */
:root {
  /* Base palette */
  --clr-white:       #fafaf9;
  --clr-offwhite:    #f5f4f1;
  --clr-tinted:      #f0efe9;
  --clr-ink:         #111110;
  --clr-ink-80:      #28271f;
  --clr-ink-60:      #4a4840;
  --clr-ink-40:      #7a7870;
  --clr-ink-20:      #b8b6ae;
  --clr-border:      #e2e0da;
  --clr-border-mid:  #c8c6be;

  /* Accents */
  --clr-blue:        #1a4f8a;        /* ISRO-inspired deep blue */
  --clr-blue-light:  #2563ad;
  --clr-blue-bg:     #eef3fb;
  --clr-amber:       #c9520a;        /* optical beacon warm accent */
  --clr-amber-light: #ea6c20;
  --clr-green:       #1a7a45;
  --clr-red:         #b91c1c;

  /* Dark sections */
  --clr-dark:        #0d1117;
  --clr-dark-2:      #161b22;
  --clr-dark-border: #2a2f38;
  --clr-dark-text:   #e6e4dc;
  --clr-dark-sub:    #8a887e;

  /* Typography */
  --font-main: 'Inter', system-ui, -apple-system, sans-serif;

  /* Spacing scale */
  --space-1:  0.25rem;
  --space-2:  0.5rem;
  --space-3:  0.75rem;
  --space-4:  1rem;
  --space-5:  1.25rem;
  --space-6:  1.5rem;
  --space-8:  2rem;
  --space-10: 2.5rem;
  --space-12: 3rem;
  --space-16: 4rem;
  --space-20: 5rem;
  --space-24: 6rem;
  --space-32: 8rem;

  /* Radii */
  --radius-sm:  4px;
  --radius-md:  8px;
  --radius-lg:  12px;
  --radius-xl:  16px;
  --radius-2xl: 24px;

  /* Shadows */
  --shadow-sm:  0 1px 3px rgba(0,0,0,.06), 0 1px 2px rgba(0,0,0,.04);
  --shadow-md:  0 4px 12px rgba(0,0,0,.08), 0 2px 4px rgba(0,0,0,.04);
  --shadow-lg:  0 12px 40px rgba(0,0,0,.12), 0 4px 12px rgba(0,0,0,.06);
  --shadow-xl:  0 24px 64px rgba(0,0,0,.16), 0 8px 24px rgba(0,0,0,.08);

  /* Nav */
  --nav-h: 60px;
}

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

html {
  scroll-behavior: smooth;
  -webkit-text-size-adjust: 100%;
  font-size: 16px;
}

body {
  font-family: var(--font-main);
  background: var(--clr-white);
  color: var(--clr-ink);
  line-height: 1.6;
  overflow-x: hidden;
}

img { display: block; max-width: 100%; height: auto; }
a { color: inherit; text-decoration: none; }
ul { list-style: none; }
button { font-family: inherit; cursor: pointer; }

/* ── Layout helpers ──────────────────────────────────────────────── */
.container {
  width: 100%;
  max-width: 1160px;
  margin-inline: auto;
  padding-inline: var(--space-6);
}

.section {
  padding-block: var(--space-24);
  scroll-margin-top: var(--nav-h);
}

.section-dark {
  background: var(--clr-dark);
  color: var(--clr-dark-text);
}

.section-tinted {
  background: var(--clr-tinted);
}

/* ── Typography ──────────────────────────────────────────────────── */
.section-label {
  font-size: 0.7rem;
  font-weight: 600;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--clr-blue);
  margin-bottom: var(--space-3);
}
.section-label-light { color: #5b8fd4; }

.section-title {
  font-size: clamp(1.75rem, 3.5vw, 2.5rem);
  font-weight: 800;
  letter-spacing: -0.025em;
  line-height: 1.18;
  color: var(--clr-ink);
  margin-bottom: var(--space-4);
}
.section-title-light { color: var(--clr-dark-text); }

.section-sub {
  font-size: 1.05rem;
  color: var(--clr-ink-60);
  max-width: 560px;
  margin-bottom: var(--space-10);
  line-height: 1.65;
}
.section-sub-light { color: var(--clr-dark-sub); }

/* ── Buttons ─────────────────────────────────────────────────────── */
.btn {
  display: inline-flex;
  align-items: center;
  gap: var(--space-2);
  border-radius: var(--radius-lg);
  font-weight: 600;
  font-size: 0.9rem;
  letter-spacing: -0.005em;
  transition: all 0.18s ease;
  white-space: nowrap;
  border: 1.5px solid transparent;
  text-decoration: none;
}

.btn-sm  { padding: var(--space-2) var(--space-4);   font-size: 0.82rem; border-radius: var(--radius-md); }
.btn-lg  { padding: var(--space-4) var(--space-8);   font-size: 0.95rem; }

.btn-primary {
  background: var(--clr-blue);
  color: #fff;
  border-color: var(--clr-blue);
}
.btn-primary:hover {
  background: var(--clr-blue-light);
  border-color: var(--clr-blue-light);
  transform: translateY(-1px);
  box-shadow: 0 4px 16px rgba(26,79,138,.3);
}

.btn-outline {
  background: transparent;
  color: var(--clr-ink);
  border-color: var(--clr-border-mid);
}
.btn-outline:hover {
  border-color: var(--clr-ink-60);
  background: var(--clr-offwhite);
  transform: translateY(-1px);
}

.btn-ghost {
  background: transparent;
  color: var(--clr-ink-60);
  border-color: transparent;
}
.btn-ghost:hover {
  color: var(--clr-ink);
  background: var(--clr-offwhite);
}

/* ── Navigation ──────────────────────────────────────────────────── */
.nav-wrapper {
  position: sticky;
  top: 0;
  z-index: 200;
  height: var(--nav-h);
  background: rgba(250,250,249,.92);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--clr-border);
  transition: border-color 0.2s;
}

.nav-inner {
  max-width: 1160px;
  margin-inline: auto;
  padding-inline: var(--space-6);
  height: 100%;
  display: flex;
  align-items: center;
  gap: var(--space-8);
}

.nav-brand {
  display: flex;
  align-items: center;
  gap: var(--space-3);
  flex-shrink: 0;
}
.nav-logo-img {
  width: 28px;
  height: 28px;
  border-radius: var(--radius-sm);
}
.nav-brand-name {
  font-size: 1rem;
  font-weight: 700;
  letter-spacing: -0.02em;
  color: var(--clr-ink);
}

.nav-links {
  display: flex;
  align-items: center;
  gap: var(--space-1);
  margin-inline: auto;
}
.nav-link {
  font-size: 0.875rem;
  font-weight: 500;
  color: var(--clr-ink-60);
  padding: var(--space-2) var(--space-3);
  border-radius: var(--radius-md);
  transition: color 0.15s, background 0.15s;
}
.nav-link:hover {
  color: var(--clr-ink);
  background: var(--clr-offwhite);
}

.nav-actions {
  display: flex;
  align-items: center;
  gap: var(--space-2);
  flex-shrink: 0;
}

.nav-toggle {
  display: none;
  flex-direction: column;
  gap: 5px;
  background: none;
  border: none;
  padding: var(--space-2);
  margin-left: auto;
}
.nav-toggle span {
  display: block;
  width: 22px;
  height: 2px;
  background: var(--clr-ink);
  border-radius: 2px;
  transition: all 0.2s;
}

/* ── Hero ────────────────────────────────────────────────────────── */
.hero {
  text-align: center;
  padding-top: var(--space-20);
  padding-bottom: 0;
  padding-inline: var(--space-6);
  overflow: hidden;
}

.hero-eyebrow {
  display: inline-flex;
  align-items: center;
  gap: var(--space-3);
  font-size: 0.72rem;
  font-weight: 600;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--clr-ink-40);
  background: var(--clr-offwhite);
  border: 1px solid var(--clr-border);
  border-radius: 100px;
  padding: var(--space-2) var(--space-5);
  margin-bottom: var(--space-8);
}
.eyebrow-dot {
  width: 6px;
  height: 6px;
  background: var(--clr-amber);
  border-radius: 50%;
  animation: pulse-dot 2s ease infinite;
}
@keyframes pulse-dot {
  0%, 100% { opacity: 1; transform: scale(1); }
  50% { opacity: 0.5; transform: scale(0.8); }
}

.hero-headline {
  font-size: clamp(3.5rem, 9vw, 7rem);
  font-weight: 900;
  letter-spacing: -0.04em;
  line-height: 1.0;
  color: var(--clr-ink);
  margin-bottom: var(--space-5);
  background: linear-gradient(160deg, var(--clr-ink) 0%, var(--clr-ink-60) 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.hero-subhead {
  font-size: clamp(1.1rem, 2.5vw, 1.5rem);
  font-weight: 400;
  color: var(--clr-ink-60);
  letter-spacing: -0.01em;
  line-height: 1.45;
  margin-bottom: var(--space-6);
  max-width: 640px;
  margin-inline: auto;
}

.hero-body {
  font-size: 0.975rem;
  color: var(--clr-ink-60);
  max-width: 540px;
  margin-inline: auto;
  margin-bottom: var(--space-8);
  line-height: 1.7;
}

.hero-actions {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-4);
  flex-wrap: wrap;
  margin-bottom: var(--space-5);
}

.hero-scroll-link {
  font-size: 0.82rem;
  color: var(--clr-ink-40);
  letter-spacing: 0.01em;
  margin-bottom: var(--space-12);
  display: inline-block;
  transition: color 0.15s;
}
.hero-scroll-link:hover { color: var(--clr-ink); }

/* Hero visual */
.hero-visual-wrapper {
  max-width: 1100px;
  margin-inline: auto;
  position: relative;
  padding-bottom: var(--space-6);
}

.hero-frame {
  position: relative;
  border-radius: var(--radius-xl) var(--radius-xl) 0 0;
  border: 1.5px solid var(--clr-border);
  border-bottom: none;
  background: var(--clr-dark-2);
  padding: var(--space-3);
  box-shadow: var(--shadow-xl);
  overflow: hidden;
}

.hero-screenshot {
  width: 100%;
  border-radius: var(--radius-md);
  display: block;
}

/* Annotation badges */
.annotation {
  position: absolute;
  z-index: 10;
  background: rgba(13,17,23,.85);
  backdrop-filter: blur(8px);
  border: 1px solid var(--clr-dark-border);
  border-radius: var(--radius-md);
  padding: var(--space-2) var(--space-3);
  font-size: 0.68rem;
  font-weight: 600;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--clr-dark-text);
  display: flex;
  align-items: center;
  gap: var(--space-2);
  pointer-events: none;
}
.ann-tl { top: var(--space-5); left: var(--space-5); }
.ann-tr { top: var(--space-5); right: var(--space-5); }
.ann-bl { bottom: var(--space-5); left: var(--space-5); }
.ann-br { bottom: var(--space-5); right: var(--space-5); font-size: 0.85rem; }
.ann-br small { font-size: 0.62rem; font-weight: 400; }
.ann-bl strong { color: var(--clr-amber-light); }

.ann-dot {
  width: 7px;
  height: 7px;
  border-radius: 50%;
  flex-shrink: 0;
}
.ann-green { background: #22c55e; box-shadow: 0 0 6px rgba(34,197,94,.6); animation: pulse-dot 2s ease infinite; }
.ann-amber { background: var(--clr-amber-light); box-shadow: 0 0 6px rgba(234,108,32,.6); animation: pulse-dot 2.5s ease infinite; }
.ann-red   { background: #ef4444; box-shadow: 0 0 6px rgba(239,68,68,.6); }

@keyframes reticle-spin {
  from { transform: rotate(0deg); }
  to   { transform: rotate(360deg); }
}

/* Telemetry strip */
.telemetry-strip {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 0;
  background: var(--clr-dark);
  border: 1.5px solid var(--clr-dark-border);
  border-top: none;
  border-radius: 0 0 var(--radius-xl) var(--radius-xl);
  padding: var(--space-4) var(--space-6);
  max-width: 700px;
  margin-inline: auto;
}
.telem-item {
  display: flex;
  flex-direction: column;
  align-items: center;
  padding-inline: var(--space-6);
}
.telem-sep {
  width: 1px;
  height: 32px;
  background: var(--clr-dark-border);
}
.telem-label {
  font-size: 0.62rem;
  font-weight: 600;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--clr-dark-sub);
  margin-bottom: 2px;
}
.telem-value {
  font-size: 0.88rem;
  font-weight: 600;
  color: var(--clr-dark-text);
  font-variant-numeric: tabular-nums;
  font-feature-settings: "tnum";
}
.telem-green { color: #4ade80; }

/* ── Feature Cards ───────────────────────────────────────────────── */
.cards-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
  gap: var(--space-4);
}

.card {
  background: var(--clr-white);
  border: 1.5px solid var(--clr-border);
  border-radius: var(--radius-xl);
  padding: var(--space-6);
  transition: border-color 0.2s, box-shadow 0.2s, transform 0.2s;
}
.card:hover {
  border-color: var(--clr-border-mid);
  box-shadow: var(--shadow-md);
  transform: translateY(-2px);
}

.card-icon {
  width: 40px;
  height: 40px;
  color: var(--clr-blue);
  margin-bottom: var(--space-4);
}
.card-icon svg {
  width: 100%;
  height: 100%;
}

.card-title {
  font-size: 0.975rem;
  font-weight: 700;
  letter-spacing: -0.01em;
  color: var(--clr-ink);
  margin-bottom: var(--space-2);
}

.card-body {
  font-size: 0.875rem;
  color: var(--clr-ink-60);
  line-height: 1.65;
}

/* ── Problem Section ─────────────────────────────────────────────── */
.problem-layout {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: var(--space-12);
  align-items: start;
}

.problem-text p {
  font-size: 0.975rem;
  color: var(--clr-dark-sub);
  line-height: 1.7;
  margin-bottom: var(--space-5);
}

.problem-specs {
  border-top: 1px solid var(--clr-dark-border);
  padding-top: var(--space-5);
  display: flex;
  flex-direction: column;
  gap: var(--space-3);
}
.problem-specs li {
  display: flex;
  justify-content: space-between;
  align-items: center;
  font-size: 0.85rem;
  gap: var(--space-4);
}
.spec-key { color: var(--clr-dark-sub); flex-shrink: 0; }
.spec-val { color: var(--clr-dark-text); font-weight: 500; text-align: right; font-variant-numeric: tabular-nums; }

/* FOV Diagram */
.fov-diagram {
  background: var(--clr-dark-2);
  border: 1px solid var(--clr-dark-border);
  border-radius: var(--radius-xl);
  padding: var(--space-6);
}
.fov-world {
  position: relative;
  height: 220px;
  border: 1px dashed var(--clr-dark-border);
  border-radius: var(--radius-lg);
  background: rgba(255,255,255,.02);
  overflow: hidden;
  margin-bottom: var(--space-4);
}
.fov-label-top {
  position: absolute;
  top: var(--space-2);
  left: var(--space-3);
  font-size: 0.65rem;
  color: var(--clr-dark-sub);
  letter-spacing: 0.05em;
}
.beacon-path {
  position: absolute;
  inset: 0;
}
.beacon-dot {
  position: absolute;
  width: 10px;
  height: 10px;
  background: #ea6c20;
  border-radius: 50%;
  box-shadow: 0 0 12px rgba(234,108,32,.8), 0 0 24px rgba(234,108,32,.3);
  top: 50%;
  left: 20%;
  transform: translate(-50%, -50%);
  animation: beacon-figure8 6s ease-in-out infinite;
}
@keyframes beacon-figure8 {
  0%   { top: 50%; left: 20%; }
  12%  { top: 30%; left: 40%; }
  25%  { top: 50%; left: 60%; }
  37%  { top: 70%; left: 40%; }
  50%  { top: 50%; left: 20%; }
  62%  { top: 30%; left: 40%; }
  75%  { top: 50%; left: 80%; }
  87%  { top: 70%; left: 60%; }
  100% { top: 50%; left: 20%; }
}
.fov-box {
  position: absolute;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  width: 160px;
  height: 120px;
  border: 1.5px solid rgba(91,143,212,.6);
  border-radius: var(--radius-sm);
  display: flex;
  align-items: center;
  justify-content: center;
  background: rgba(91,143,212,.03);
}
.fov-box-label {
  position: absolute;
  bottom: -20px;
  left: 50%;
  transform: translateX(-50%);
  font-size: 0.62rem;
  color: var(--clr-dark-sub);
  white-space: nowrap;
}
.fov-reticle {
  width: 30px;
  height: 30px;
  border: 1px solid rgba(234,108,32,.6);
  border-radius: 50%;
  animation: reticle-spin 4s linear infinite;
}
.fov-annotations {
  display: flex;
  flex-direction: column;
  gap: var(--space-2);
  margin-top: var(--space-6);
}
.fov-ann {
  display: flex;
  align-items: center;
  gap: var(--space-2);
  font-size: 0.78rem;
  color: var(--clr-dark-sub);
}

/* ── Pipeline / How It Works ─────────────────────────────────────── */
.pipeline-wrapper {
  position: relative;
}

.pipeline-steps {
  display: grid;
  grid-template-columns: 1fr auto 1fr auto 1fr auto 1fr;
  align-items: center;
  gap: var(--space-2);
  margin-bottom: var(--space-4);
}

.pipeline-steps-row2 {
  direction: rtl;
}
.pipeline-steps-row2 > * {
  direction: ltr;
}

.pipe-step {
  background: var(--clr-white);
  border: 1.5px solid var(--clr-border);
  border-radius: var(--radius-xl);
  padding: var(--space-4) var(--space-3);
  text-align: center;
  transition: border-color 0.2s, box-shadow 0.2s;
  position: relative;
  min-width: 0;
}
.pipe-step:hover {
  border-color: var(--clr-blue);
  box-shadow: 0 0 0 3px var(--clr-blue-bg);
}

.pipe-num {
  font-size: 0.65rem;
  font-weight: 700;
  letter-spacing: 0.06em;
  color: var(--clr-ink-20);
  margin-bottom: var(--space-2);
}

.pipe-icon {
  width: 28px;
  height: 28px;
  color: var(--clr-blue);
  margin-inline: auto;
  margin-bottom: var(--space-2);
}
.pipe-icon svg { width: 100%; height: 100%; }

.pipe-step h4 {
  font-size: 0.8rem;
  font-weight: 700;
  color: var(--clr-ink);
  margin-bottom: var(--space-1);
  letter-spacing: -0.01em;
  overflow-wrap: break-word;
}

.pipe-step p {
  font-size: 0.72rem;
  color: var(--clr-ink-60);
  line-height: 1.55;
  overflow-wrap: break-word;
}

.pipe-arrow {
  font-size: 1.1rem;
  color: var(--clr-ink-20);
  flex-shrink: 0;
  font-weight: 300;
}

.pipeline-feedback-label {
  text-align: center;
  font-size: 0.72rem;
  font-weight: 600;
  letter-spacing: 0.06em;
  color: var(--clr-amber);
  padding-block: var(--space-2);
  border-left: 2px solid var(--clr-amber);
  border-right: 2px solid var(--clr-amber);
  border-radius: var(--radius-sm);
  margin-inline: var(--space-6);
  margin-bottom: var(--space-4);
  background: rgba(201,82,10,.04);
}

.pipeline-output {
  display: flex;
  justify-content: center;
  margin-top: var(--space-6);
}
.output-box {
  display: flex;
  align-items: center;
  gap: var(--space-3);
  background: var(--clr-tinted);
  border: 1.5px solid var(--clr-border);
  border-radius: var(--radius-lg);
  padding: var(--space-3) var(--space-6);
  font-size: 0.85rem;
  font-weight: 600;
  color: var(--clr-ink-60);
}

/* ── Modes ───────────────────────────────────────────────────────── */
.modes-grid {
  display: grid;
  grid-template-columns: 1fr auto 1fr;
  gap: var(--space-6);
  align-items: center;
}

.mode-card {
  background: var(--clr-white);
  border: 1.5px solid var(--clr-border);
  border-radius: var(--radius-2xl);
  padding: var(--space-8);
  height: 100%;
  min-width: 0;
}

.mode-badge {
  display: inline-block;
  font-size: 0.65rem;
  font-weight: 700;
  letter-spacing: 0.1em;
  background: var(--clr-blue);
  color: #fff;
  padding: var(--space-1) var(--space-3);
  border-radius: var(--radius-sm);
  margin-bottom: var(--space-4);
}
.mode-badge-b {
  background: var(--clr-amber);
}

.mode-title {
  font-size: 1.2rem;
  font-weight: 800;
  letter-spacing: -0.02em;
  color: var(--clr-ink);
  margin-bottom: var(--space-3);
}

.mode-desc {
  font-size: 0.875rem;
  color: var(--clr-ink-60);
  line-height: 1.65;
  margin-bottom: var(--space-6);
}

.mode-flow {
  display: flex;
  align-items: center;
  gap: var(--space-2);
  margin-bottom: var(--space-5);
  flex-wrap: wrap;
}
.mode-node {
  font-size: 0.72rem;
  font-weight: 600;
  background: var(--clr-offwhite);
  border: 1px solid var(--clr-border);
  border-radius: var(--radius-md);
  padding: var(--space-2) var(--space-3);
  color: var(--clr-ink-60);
  text-align: center;
  line-height: 1.3;
}
.mode-node small { font-size: 0.62rem; font-weight: 400; display: block; }
.mode-node-accent {
  background: var(--clr-blue-bg);
  border-color: rgba(37,99,173,.3);
  color: var(--clr-blue);
}
.mode-arrow { color: var(--clr-ink-20); font-size: 0.9rem; }

.mode-specs {
  display: flex;
  flex-direction: column;
  gap: var(--space-2);
  border-top: 1px solid var(--clr-border);
  padding-top: var(--space-4);
}
.mode-specs li {
  font-size: 0.8rem;
  color: var(--clr-ink-60);
  padding-left: var(--space-4);
  position: relative;
}
.mode-specs li::before {
  content: '→';
  position: absolute;
  left: 0;
  color: var(--clr-blue);
  font-weight: 700;
}

.modes-convergence {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: var(--space-3);
}
.convergence-line {
  width: 1.5px;
  height: 60px;
  background: linear-gradient(to bottom, var(--clr-border), var(--clr-blue));
}
.convergence-label {
  background: var(--clr-blue-bg);
  border: 1.5px solid rgba(37,99,173,.3);
  border-radius: var(--radius-lg);
  padding: var(--space-3) var(--space-4);
  font-size: 0.72rem;
  font-weight: 700;
  color: var(--clr-blue);
  text-align: center;
  letter-spacing: -0.01em;
}
.convergence-label small {
  display: block;
  font-weight: 400;
  font-size: 0.65rem;
  color: rgba(37,99,173,.7);
  margin-top: 2px;
}

/* ── Architecture ────────────────────────────────────────────────── */
.arch-diagram {
  display: flex;
  flex-direction: column;
  gap: 0;
}

.arch-tier {
  border: 1.5px solid var(--clr-border);
  border-radius: var(--radius-xl);
  overflow: hidden;
  background: var(--clr-white);
}

.arch-tier-label {
  background: var(--clr-offwhite);
  border-bottom: 1px solid var(--clr-border);
  padding: var(--space-3) var(--space-6);
  font-size: 0.65rem;
  font-weight: 700;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--clr-ink-60);
}

.arch-tier-body {
  padding: var(--space-5) var(--space-6);
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: var(--space-6);
}
.arch-tier-3col {
  grid-template-columns: repeat(3, 1fr);
}
.arch-tier-body-single {
  grid-template-columns: 1fr;
}

.arch-col {
  display: flex;
  flex-direction: column;
  gap: var(--space-2);
  min-width: 0;
}

.arch-tag {
  font-size: 0.65rem;
  font-weight: 700;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  padding: var(--space-1) var(--space-3);
  border-radius: var(--radius-sm);
  display: inline-flex;
  width: fit-content;
  margin-bottom: var(--space-1);
}
.arch-tag-a { background: var(--clr-blue-bg); color: var(--clr-blue); }
.arch-tag-b { background: rgba(201,82,10,.1); color: var(--clr-amber); }

.arch-item {
  display: flex;
  align-items: flex-start;
  gap: var(--space-4);
  padding: var(--space-2) 0;
  border-bottom: 1px solid var(--clr-border);
  font-size: 0.8rem;
}
.arch-item:last-child { border-bottom: none; }
.arch-item code {
  font-family: 'SFMono-Regular', 'Consolas', 'Liberation Mono', monospace;
  font-size: 0.78rem;
  color: var(--clr-blue);
  background: var(--clr-blue-bg);
  padding: 1px var(--space-2);
  border-radius: 3px;
  flex-shrink: 0;
  white-space: nowrap;
}
.arch-item span {
  color: var(--clr-ink-60);
  flex: 1;
}

.arch-item-h {
  font-size: 0.85rem;
  font-weight: 700;
  color: var(--clr-ink);
  padding-bottom: var(--space-2);
  border-bottom: 1px solid var(--clr-border);
  margin-bottom: var(--space-2);
}
.arch-item-h code {
  font-family: 'SFMono-Regular', 'Consolas', monospace;
  font-size: 0.82rem;
  background: none;
  color: var(--clr-ink);
  padding: 0;
  border-radius: 0;
}

.arch-tier-output {
  background: var(--clr-blue-bg);
  border-top: 1px solid rgba(37,99,173,.2);
  padding: var(--space-3) var(--space-6);
  font-size: 0.78rem;
  color: var(--clr-blue);
  font-weight: 500;
}
.arch-tier-output code {
  font-family: 'SFMono-Regular', 'Consolas', monospace;
  font-size: 0.78rem;
}

.arch-connector {
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--clr-border-mid);
  font-size: 1.5rem;
  padding-block: var(--space-1);
}

.arch-tier-telem .arch-item-h {
  margin-bottom: var(--space-4);
}
.telem-chips {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-2);
}
.chip {
  font-size: 0.75rem;
  font-weight: 500;
  background: var(--clr-offwhite);
  border: 1px solid var(--clr-border);
  border-radius: 100px;
  padding: var(--space-1) var(--space-4);
  color: var(--clr-ink-60);
}

/* ── Performance Metrics ─────────────────────────────────────────── */
.metrics-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(220px, 1fr));
  gap: var(--space-4);
  margin-bottom: var(--space-8);
}

.metric-card {
  border: 1px solid var(--clr-dark-border);
  border-radius: var(--radius-xl);
  padding: var(--space-6);
  background: var(--clr-dark-2);
  transition: border-color 0.2s, transform 0.2s;
}
.metric-card:hover {
  border-color: rgba(91,143,212,.5);
  transform: translateY(-2px);
}

.metric-primary {
  grid-column: span 1;
  border-color: rgba(37,99,173,.5);
  background: rgba(37,99,173,.08);
}

.metric-accent {
  border-color: rgba(234,108,32,.4);
  background: rgba(201,82,10,.05);
}

.metric-value {
  font-size: 2.8rem;
  font-weight: 900;
  letter-spacing: -0.04em;
  line-height: 1.0;
  color: var(--clr-dark-text);
  margin-bottom: var(--space-1);
  font-variant-numeric: tabular-nums;
}
.metric-lt { font-size: 2.2rem; }
.metric-decimal { font-size: 2.4rem; }

.metric-unit {
  font-size: 0.7rem;
  font-weight: 600;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--clr-dark-sub);
  margin-bottom: var(--space-3);
}

.metric-label {
  font-size: 0.82rem;
  font-weight: 600;
  color: var(--clr-dark-text);
  line-height: 1.4;
}

.metric-note {
  font-size: 0.72rem;
  color: var(--clr-dark-sub);
  margin-top: var(--space-2);
}

.perf-footnote {
  font-size: 0.8rem;
  color: var(--clr-dark-sub);
  text-align: center;
  border-top: 1px solid var(--clr-dark-border);
  padding-top: var(--space-5);
}

/* ── Technology ──────────────────────────────────────────────────── */
.tech-layout {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: var(--space-12);
  align-items: start;
}

.tech-col-title {
  font-size: 0.7rem;
  font-weight: 700;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--clr-ink-40);
  margin-bottom: var(--space-5);
  padding-bottom: var(--space-3);
  border-bottom: 1px solid var(--clr-border);
}

.tech-list {
  display: flex;
  flex-direction: column;
  gap: var(--space-3);
}

.tech-item {
  display: flex;
  align-items: center;
  gap: var(--space-4);
  padding: var(--space-3) 0;
  border-bottom: 1px solid var(--clr-border);
}
.tech-item:last-child { border-bottom: none; }

.tech-item-icon {
  width: 36px;
  height: 36px;
  border-radius: var(--radius-md);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 0.72rem;
  font-weight: 800;
  flex-shrink: 0;
  letter-spacing: -0.02em;
}
.python-icon { background: #1d4a7a; color: #f0f; background: linear-gradient(135deg, #3776ab, #ffd343); color: #000; }
.cv-icon     { background: #1d5c2a; color: #fff; }
.np-icon     { background: #4c72b0; color: #fff; }
.qt-icon     { background: #41cd52; color: #fff; }
.pg-icon     { background: #1a4a5e; color: #fff; }
.pi-icon     { background: #2d2d2d; color: #e8c84d; }

.tech-item-name {
  font-size: 0.9rem;
  font-weight: 600;
  color: var(--clr-ink);
  letter-spacing: -0.01em;
}
.tech-item-sub {
  font-size: 0.78rem;
  color: var(--clr-ink-60);
  margin-top: 1px;
}

.algo-list {
  display: flex;
  flex-direction: column;
  gap: 0;
}
.algo-item {
  padding: var(--space-4) 0;
  border-bottom: 1px solid var(--clr-border);
}
.algo-item:last-child { border-bottom: none; }
.algo-label {
  font-size: 0.85rem;
  font-weight: 600;
  color: var(--clr-ink);
  margin-bottom: var(--space-1);
}
.algo-formula {
  font-family: 'SFMono-Regular', 'Consolas', monospace;
  font-size: 0.78rem;
  color: var(--clr-blue);
  background: var(--clr-blue-bg);
  padding: var(--space-2) var(--space-3);
  border-radius: var(--radius-sm);
  display: inline-block;
}

/* ── Download Section ────────────────────────────────────────────── */
.section-download {
  background: var(--clr-ink);
  color: var(--clr-white);
}

.download-inner {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: var(--space-12);
  align-items: center;
}

.download-title {
  font-size: clamp(2rem, 4vw, 3rem);
  font-weight: 900;
  letter-spacing: -0.03em;
  color: var(--clr-white);
  margin-bottom: var(--space-4);
  margin-top: var(--space-3);
}

.download-body {
  font-size: 0.975rem;
  color: var(--clr-ink-20);
  line-height: 1.7;
  margin-bottom: var(--space-8);
  max-width: 440px;
}

.download-actions {
  display: flex;
  align-items: center;
  gap: var(--space-4);
  flex-wrap: wrap;
  margin-bottom: var(--space-5);
}
.section-download .btn-primary {
  background: var(--clr-white);
  color: var(--clr-ink);
  border-color: var(--clr-white);
}
.section-download .btn-primary:hover {
  background: var(--clr-offwhite);
  border-color: var(--clr-offwhite);
  box-shadow: 0 4px 16px rgba(255,255,255,.2);
}
.section-download .btn-outline {
  color: var(--clr-dark-text);
  border-color: rgba(255,255,255,.25);
}
.section-download .btn-outline:hover {
  background: rgba(255,255,255,.06);
  border-color: rgba(255,255,255,.45);
}

.download-meta {
  display: flex;
  align-items: center;
  gap: var(--space-3);
  flex-wrap: wrap;
}
.dl-tag {
  display: inline-flex;
  align-items: center;
  gap: var(--space-1);
  font-size: 0.75rem;
  color: var(--clr-ink-40);
  background: rgba(255,255,255,.06);
  border: 1px solid rgba(255,255,255,.1);
  border-radius: 100px;
  padding: var(--space-1) var(--space-3);
}

/* Download card */
.dl-card {
  background: var(--clr-dark-2);
  border: 1px solid var(--clr-dark-border);
  border-radius: var(--radius-xl);
  overflow: hidden;
}
.dl-card-header {
  background: rgba(255,255,255,.03);
  border-bottom: 1px solid var(--clr-dark-border);
  padding: var(--space-3) var(--space-5);
  display: flex;
  align-items: center;
  gap: var(--space-3);
}
.dl-dots {
  display: flex;
  gap: 5px;
}
.dl-dots span {
  width: 10px;
  height: 10px;
  border-radius: 50%;
  background: var(--clr-dark-border);
}
.dl-dots span:nth-child(1) { background: #ff5f57; }
.dl-dots span:nth-child(2) { background: #ffbd2e; }
.dl-dots span:nth-child(3) { background: #28c840; }
.dl-card-title {
  font-size: 0.78rem;
  color: var(--clr-dark-sub);
  font-weight: 500;
  margin-left: var(--space-2);
}
.dl-card-body {
  padding: var(--space-6);
  display: flex;
  flex-direction: column;
  gap: var(--space-4);
}
.dl-file {
  display: flex;
  align-items: center;
  gap: var(--space-4);
  color: var(--clr-dark-text);
}
.dl-file svg { color: var(--clr-blue-light); flex-shrink: 0; }
.dl-filename { font-size: 0.9rem; font-weight: 600; }
.dl-filesize { font-size: 0.75rem; color: var(--clr-dark-sub); margin-top: 2px; }
.dl-hash {
  font-size: 0.72rem;
  color: var(--clr-dark-sub);
  display: flex;
  align-items: center;
  gap: var(--space-3);
  font-family: 'SFMono-Regular', 'Consolas', monospace;
}
.dl-hash-label {
  background: rgba(255,255,255,.06);
  padding: 2px var(--space-2);
  border-radius: 3px;
  font-family: var(--font-main);
  font-weight: 600;
  letter-spacing: 0.04em;
}
.dl-hash-val { opacity: 0.7; }
.dl-release-info {
  display: flex;
  justify-content: space-between;
  font-size: 0.78rem;
  color: var(--clr-dark-sub);
  padding-top: var(--space-3);
  border-top: 1px solid var(--clr-dark-border);
}

/* ── Source Section ──────────────────────────────────────────────── */
.source-inner {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: var(--space-12);
  align-items: center;
}

.source-title {
  font-size: clamp(1.75rem, 3.5vw, 2.5rem);
  font-weight: 800;
  letter-spacing: -0.025em;
  color: var(--clr-ink);
  margin-bottom: var(--space-4);
  margin-top: var(--space-3);
}

.source-body {
  font-size: 0.975rem;
  color: var(--clr-ink-60);
  line-height: 1.7;
  margin-bottom: var(--space-6);
  max-width: 440px;
}

.source-list {
  display: flex;
  flex-direction: column;
  gap: var(--space-3);
  margin-bottom: var(--space-8);
}
.source-list li {
  display: flex;
  align-items: center;
  gap: var(--space-3);
  font-size: 0.875rem;
  color: var(--clr-ink-60);
}
.source-list li::before {
  content: '✓';
  font-weight: 700;
  color: var(--clr-green);
  flex-shrink: 0;
}

/* Repo card */
.repo-card {
  background: var(--clr-white);
  border: 1.5px solid var(--clr-border);
  border-radius: var(--radius-xl);
  padding: var(--space-6);
  box-shadow: var(--shadow-md);
}
.repo-card-header {
  display: flex;
  align-items: center;
  gap: var(--space-3);
  font-size: 0.9rem;
  font-weight: 600;
  color: var(--clr-ink);
  margin-bottom: var(--space-3);
}
.repo-card-header svg { color: var(--clr-ink-60); }
.repo-desc {
  font-size: 0.82rem;
  color: var(--clr-ink-60);
  line-height: 1.55;
  margin-bottom: var(--space-4);
  padding-bottom: var(--space-4);
  border-bottom: 1px solid var(--clr-border);
}
.repo-langs {
  display: flex;
  align-items: center;
  gap: var(--space-2);
  font-size: 0.78rem;
  color: var(--clr-ink-60);
  margin-bottom: var(--space-4);
}
.lang-dot {
  width: 10px;
  height: 10px;
  border-radius: 50%;
}
.python-dot { background: #3776ab; }
.repo-files {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: var(--space-2);
}
.rf {
  font-family: 'SFMono-Regular', 'Consolas', monospace;
  font-size: 0.72rem;
  color: var(--clr-blue);
  background: var(--clr-blue-bg);
  padding: var(--space-1) var(--space-2);
  border-radius: var(--radius-sm);
  text-align: center;
}

/* ── Footer ──────────────────────────────────────────────────────── */
.footer {
  background: var(--clr-offwhite);
  border-top: 1px solid var(--clr-border);
  padding-block: var(--space-8) var(--space-6);
}

.footer-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-6);
  flex-wrap: wrap;
  padding-bottom: var(--space-5);
  border-bottom: 1px solid var(--clr-border);
  margin-bottom: var(--space-4);
}

.footer-brand {
  display: flex;
  align-items: center;
  gap: var(--space-2);
}
.footer-brand img { border-radius: var(--radius-sm); }
.footer-brand-name {
  font-size: 0.9rem;
  font-weight: 700;
  letter-spacing: -0.015em;
  color: var(--clr-ink);
}

.footer-meta {
  font-size: 0.78rem;
  color: var(--clr-ink-40);
  text-align: center;
  flex: 1;
}

.footer-links {
  display: flex;
  align-items: center;
  gap: var(--space-5);
}
.footer-links a {
  font-size: 0.82rem;
  color: var(--clr-ink-60);
  transition: color 0.15s;
}
.footer-links a:hover { color: var(--clr-ink); }

.footer-bottom {
  display: flex;
  justify-content: space-between;
  align-items: center;
  font-size: 0.75rem;
  color: var(--clr-ink-40);
  gap: var(--space-4);
  flex-wrap: wrap;
}

/* ── Utility ─────────────────────────────────────────────────────── */
.break-tablet { display: none; }

/* ── Scroll reveal ───────────────────────────────────────────────── */
.reveal {
  opacity: 0;
  transform: translateY(20px);
  transition: opacity 0.55s ease, transform 0.55s ease;
}
.reveal.visible {
  opacity: 1;
  transform: translateY(0);
}

@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
  }
  .reveal { opacity: 1; transform: none; }
}

/* ═══════════════════════════════════════════════════════════════════
   RESPONSIVE
   ═══════════════════════════════════════════════════════════════════ */

/* Mobile (<= 768px) */
@media (max-width: 768px) {
  :root { --nav-h: 56px; }

  .nav-actions .btn-ghost { display: none; }

  .nav-links {
    display: none;
    position: fixed;
    top: var(--nav-h);
    left: 0;
    right: 0;
    background: var(--clr-white);
    border-bottom: 1px solid var(--clr-border);
    flex-direction: column;
    align-items: stretch;
    padding: var(--space-4);
    gap: var(--space-1);
    z-index: 199;
    box-shadow: var(--shadow-lg);
  }
  .nav-links.open { display: flex; }
  .nav-link { padding: var(--space-3) var(--space-4); border-radius: var(--radius-md); }

  .nav-toggle { display: flex; }

  .hero { padding-top: var(--space-12); }
  .hero-headline { font-size: clamp(2.8rem, 12vw, 4rem); }

  .hero-actions { flex-direction: column; align-items: stretch; }
  .hero-actions .btn { justify-content: center; }

  .problem-layout {
    grid-template-columns: 1fr;
    gap: var(--space-8);
  }

  .pipeline-steps {
    grid-template-columns: 1fr;
    gap: var(--space-3);
  }
  .pipe-arrow {
    transform: rotate(90deg);
    margin-inline: auto;
  }
  .pipeline-steps-row2 {
    direction: ltr;
  }

  .cards-grid { grid-template-columns: 1fr; }
  .metrics-grid { grid-template-columns: 1fr 1fr; }
  .metric-primary { grid-column: span 2; }

  .modes-grid {
    grid-template-columns: 1fr;
    gap: var(--space-6);
  }
  .modes-convergence { display: none; }

  .arch-tier-body,
  .arch-tier-3col { grid-template-columns: 1fr; }
  .arch-tier-body:not(.arch-tier-body-single) .arch-col + .arch-col {
    border-top: 1px solid var(--clr-border);
    padding-top: var(--space-4);
    margin-top: var(--space-2);
  }

  .tech-layout { grid-template-columns: 1fr; }

  .download-inner,
  .source-inner { grid-template-columns: 1fr; gap: var(--space-8); }
  .download-visual,
  .source-visual { display: none; }

  .footer-inner { flex-direction: column; align-items: flex-start; gap: var(--space-4); }
  .footer-meta { text-align: left; }
  .footer-bottom { flex-direction: column; align-items: flex-start; }

  .repo-files { grid-template-columns: repeat(2, 1fr); }
  .telem-item { padding-inline: var(--space-3); }
  .break-tablet { display: block; }
}

@media (max-width: 480px) {
  .metrics-grid { grid-template-columns: 1fr; }
  .metric-primary { grid-column: span 1; }
  .telemetry-strip { flex-wrap: wrap; row-gap: var(--space-3); }
  .telem-sep { display: none; }
}