/* ==========================================================================
   BLKPVNTHR LLC — Corporate Site
   Monochrome institutional design system.

   Palette rule: the page is grayscale. Exactly one accent (--accent) exists
   and is reserved for functional signal only — the active data series, the
   active navigation indicator, and focus rings. It is never decorative.
   ========================================================================== */

/* --------------------------------------------------------------------------
   1. Tokens
   -------------------------------------------------------------------------- */

:root {
  /* Surfaces — near-black base, graphite panels one or two steps lighter */
  --bg: #0a0a0a;
  --panel: #121316;
  --panel-2: #17181c;
  --panel-3: #1d1e23;

  /* Hairlines — low-opacity silver, never solid gray */
  --line: rgba(245, 245, 240, 0.09);
  --line-strong: rgba(245, 245, 240, 0.16);
  --line-faint: rgba(245, 245, 240, 0.05);

  /* Text — verified against WCAG AA on both --bg and --panel */
  --ink: #f5f5f0; /* 18.0:1 on --bg */
  --ink-muted: #9c9c96; /* 7.2:1 on --bg */
  --ink-faint: #87877f; /* 5.5:1 on --bg, 5.1:1 on --panel, 4.9:1 on --panel-2 */

  /* The single accent: desaturated sage. 8.7:1 on --bg. */
  --accent: #8fb4a2;
  --accent-dim: rgba(143, 180, 162, 0.16);
  --accent-line: rgba(143, 180, 162, 0.4);

  /* Type families — shared with PantherByte for family consistency */
  --font-display: 'Sora', 'Helvetica Neue', Helvetica, Arial, sans-serif;
  --font-body: 'Inter', 'Helvetica Neue', system-ui, -apple-system, sans-serif;
  --font-mono: 'JetBrains Mono', ui-monospace, SFMono-Regular, Menlo, monospace;

  /* Type scale — fluid, authored explicitly (do not rely on inherited sizes) */
  --text-2xs: 0.6875rem;
  --text-xs: 0.75rem;
  --text-sm: 0.875rem;
  --text-base: 1rem;
  --text-lg: 1.0625rem;
  --text-xl: clamp(1.125rem, 0.9rem + 0.9vw, 1.375rem);
  --text-2xl: clamp(1.375rem, 1rem + 1.6vw, 1.875rem);
  --text-3xl: clamp(1.75rem, 1.2rem + 2.6vw, 2.75rem);
  --text-4xl: clamp(2.125rem, 1.3rem + 4vw, 3.75rem);

  /* Spacing */
  --space-section: clamp(4rem, 9vw, 7.5rem);
  --space-gutter: clamp(1.25rem, 4vw, 2.5rem);

  /* Widths */
  --content: 1160px;
  --content-narrow: 680px;

  /* Geometry — sharp and technical, never pill-shaped */
  --radius: 3px;
  --radius-lg: 4px;

  /* Motion */
  --ease: cubic-bezier(0.16, 1, 0.3, 1);
  --dur: 200ms;
}

/* --------------------------------------------------------------------------
   2. Base
   -------------------------------------------------------------------------- */

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

html {
  scroll-behavior: smooth;
  scroll-padding-top: 5.5rem;
  -webkit-text-size-adjust: 100%;
}

body {
  margin: 0;
  background: var(--bg);
  color: var(--ink);
  font-family: var(--font-body);
  font-size: var(--text-base);
  line-height: 1.65;
  font-weight: 400;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  overflow-x: hidden;
}

h1,
h2,
h3,
h4 {
  font-family: var(--font-display);
  font-weight: 600;
  line-height: 1.15;
  letter-spacing: -0.02em;
  margin: 0;
  text-wrap: balance;
}

p {
  margin: 0;
  text-wrap: pretty;
}

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

ul,
ol,
dl {
  margin: 0;
  padding: 0;
  list-style: none;
}

/* Without this the UA's 40px dd indent offsets every metric value from its
   label, and the dl margins break the flush hairlines in the model panel. */
dd {
  margin: 0;
}

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

button {
  font: inherit;
  color: inherit;
  background: none;
  border: none;
  cursor: pointer;
}

hr {
  border: none;
  border-top: 1px solid var(--line);
  margin: 0;
}

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

/* Focus: the accent earns its keep here — visible, high contrast, never removed. */
:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 3px;
  border-radius: 1px;
}

:focus:not(:focus-visible) {
  outline: none;
}

/* .model and .faq clip to their rounded corners, which would slice the left and
   right edges off an outward ring on their full-bleed children. Draw it inward. */
.model-tab:focus-visible,
#graph-panel:focus-visible,
.faq summary:focus-visible {
  outline-offset: -3px;
}

.skip-link {
  position: absolute;
  top: -100%;
  left: var(--space-gutter);
  z-index: 200;
  padding: 0.75rem 1.25rem;
  background: var(--ink);
  color: var(--bg);
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  text-transform: uppercase;
  letter-spacing: 0.1em;
}

.skip-link:focus {
  top: 1rem;
}

.visually-hidden {
  position: absolute;
  width: 1px;
  height: 1px;
  margin: -1px;
  padding: 0;
  overflow: hidden;
  clip: rect(0 0 0 0);
  white-space: nowrap;
  border: 0;
}

/* --------------------------------------------------------------------------
   3. Layout primitives
   -------------------------------------------------------------------------- */

.container {
  width: 100%;
  max-width: var(--content);
  margin-inline: auto;
  padding-inline: var(--space-gutter);
}

/* The signature element: continuous 1px rules at the container edges, so the
   page reads like an engineering drawing rather than a marketing page. */
.rail {
  position: relative;
}

.rail::before,
.rail::after {
  content: '';
  position: absolute;
  top: 0;
  bottom: 0;
  width: 1px;
  background: var(--line-faint);
  pointer-events: none;
}

.rail::before {
  left: max(var(--space-gutter), calc(50% - var(--content) / 2 + var(--space-gutter)));
}

.rail::after {
  right: max(var(--space-gutter), calc(50% - var(--content) / 2 + var(--space-gutter)));
}

.section {
  padding-block: var(--space-section);
  border-top: 1px solid var(--line);
}

.section-head {
  max-width: 46rem;
  display: flex;
  flex-direction: column;
  gap: 1rem;
  margin-bottom: clamp(2.5rem, 5vw, 4rem);
}

.section-title {
  font-size: var(--text-3xl);
}

.lead {
  color: var(--ink-muted);
  font-size: var(--text-lg);
  line-height: 1.7;
}

/* Mono eyebrow with an index number — institutional report styling. */
.eyebrow {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  font-family: var(--font-mono);
  font-size: var(--text-2xs);
  font-weight: 500;
  text-transform: uppercase;
  letter-spacing: 0.18em;
  color: var(--ink-faint);
}

.eyebrow::before {
  content: '';
  width: 1.5rem;
  height: 1px;
  background: var(--line-strong);
  flex: none;
}

.eyebrow-index {
  color: var(--ink-faint);
}

/* --------------------------------------------------------------------------
   4. Header / navigation
   -------------------------------------------------------------------------- */

.site-header {
  position: sticky;
  top: 0;
  z-index: 100;
  background: rgba(10, 10, 10, 0.86);
  backdrop-filter: saturate(140%) blur(12px);
  -webkit-backdrop-filter: saturate(140%) blur(12px);
  border-bottom: 1px solid var(--line);
  transition: transform 0.28s ease;
  will-change: transform;
}

/* Slide the whole bar up on scroll-down, back down on scroll-up. JS toggles
   .is-hidden; translateY(-100%) lifts it fully off-screen, border included. */
.site-header.is-hidden {
  transform: translateY(-100%);
}

@media (prefers-reduced-motion: reduce) {
  .site-header {
    transition: none;
  }
}

.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1.5rem;
  height: 4.25rem;
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 0.625rem;
  flex: none;
}

.brand img {
  width: 38px;
  height: 38px;
  flex: none;
}

.brand-name {
  font-family: var(--font-display);
  font-size: var(--text-sm);
  font-weight: 600;
  letter-spacing: 0.04em;
}

.brand-suffix {
  color: var(--ink-faint);
  font-weight: 400;
}

.nav {
  display: flex;
  align-items: center;
  gap: 0.25rem;
  margin-left: auto;
}

.nav-link {
  position: relative;
  padding: 0.5rem 0.75rem;
  font-size: var(--text-sm);
  color: var(--ink-muted);
  transition: color var(--dur) var(--ease);
}

.nav-link:hover {
  color: var(--ink);
}

/* Active-state indicator — the one navigational use of the accent. */
.nav-link[aria-current='true'] {
  color: var(--ink);
}

.nav-link[aria-current='true']::after {
  content: '';
  position: absolute;
  left: 0.75rem;
  right: 0.75rem;
  bottom: 0.1rem;
  height: 1px;
  background: var(--accent);
}

.nav-cta {
  flex: none;
  margin-left: 0.75rem;
}

.nav-toggle {
  display: none;
  width: 2.5rem;
  height: 2.5rem;
  align-items: center;
  justify-content: center;
  border: 1px solid var(--line-strong);
  border-radius: var(--radius);
  margin-left: auto;
}

.nav-toggle span,
.nav-toggle span::before,
.nav-toggle span::after {
  display: block;
  width: 15px;
  height: 1px;
  background: var(--ink);
  transition:
    transform var(--dur) var(--ease),
    opacity var(--dur) var(--ease);
}

.nav-toggle span {
  position: relative;
}

.nav-toggle span::before,
.nav-toggle span::after {
  content: '';
  position: absolute;
  left: 0;
}

.nav-toggle span::before {
  top: -5px;
}

.nav-toggle span::after {
  top: 5px;
}

.nav-toggle[aria-expanded='true'] span {
  background: transparent;
}

.nav-toggle[aria-expanded='true'] span::before {
  transform: translateY(5px) rotate(45deg);
}

.nav-toggle[aria-expanded='true'] span::after {
  transform: translateY(-5px) rotate(-45deg);
}

/* --------------------------------------------------------------------------
   5. Buttons
   -------------------------------------------------------------------------- */

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
  padding: 0.6875rem 1.25rem;
  border-radius: var(--radius);
  font-family: var(--font-body);
  font-size: var(--text-sm);
  font-weight: 500;
  letter-spacing: 0.01em;
  border: 1px solid transparent;
  transition:
    background-color var(--dur) var(--ease),
    border-color var(--dur) var(--ease),
    color var(--dur) var(--ease);
  text-align: center;
}

.btn-primary {
  background: var(--ink);
  color: var(--bg);
  border-color: var(--ink);
}

.btn-primary:hover {
  background: #ffffff;
  border-color: #ffffff;
}

.btn-secondary {
  border-color: var(--line-strong);
  color: var(--ink);
}

.btn-secondary:hover {
  border-color: var(--ink-faint);
  background: var(--panel);
}

.btn-sm {
  padding: 0.5rem 0.9375rem;
  font-size: var(--text-xs);
}

/* Inline text link with a hairline underline that thickens on hover. */
.link {
  display: inline-flex;
  align-items: center;
  gap: 0.375rem;
  color: var(--ink);
  font-size: var(--text-sm);
  font-weight: 500;
  border-bottom: 1px solid var(--line-strong);
  padding-bottom: 2px;
  transition: border-color var(--dur) var(--ease);
}

.link:hover {
  border-bottom-color: var(--ink);
}

.link .arrow {
  transition: transform var(--dur) var(--ease);
}

.link:hover .arrow {
  transform: translateX(3px);
}

.btn-row {
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem;
}

/* --------------------------------------------------------------------------
   6. Hero
   -------------------------------------------------------------------------- */

.hero {
  padding-block: clamp(3.5rem, 8vw, 6.5rem) var(--space-section);
}

.hero-grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr) minmax(0, 1.05fr);
  gap: clamp(2.5rem, 5vw, 4.5rem);
  align-items: start;
}

.hero-copy {
  display: flex;
  flex-direction: column;
  gap: 1.5rem;
  max-width: 34rem;
}

.hero-title {
  font-size: var(--text-4xl);
  font-weight: 600;
  letter-spacing: -0.03em;
}

.hero-body {
  color: var(--ink-muted);
  font-size: var(--text-lg);
  line-height: 1.7;
}

.hero-note {
  font-family: var(--font-mono);
  font-size: var(--text-2xs);
  color: var(--ink-faint);
  line-height: 1.6;
  padding-top: 0.5rem;
  border-top: 1px solid var(--line);
  max-width: 30rem;
}

/* --------------------------------------------------------------------------
   7. Decision Evidence Graph (hero right)

   The old scenario-model composition — bar, tablist, plotting grid, three
   rising traces, legend, 2x2 objective grid, status footer — reskinned as a
   claim-safe conceptual panel. Nothing here is measured data: trace positions
   illustrate information flow (not performance) and the objective values are
   status labels (not metrics). The single accent marks the emphasized trace,
   the active-tab underline, the checkpoints, and the provenance dot only.
   -------------------------------------------------------------------------- */

.model {
  border: 1px solid var(--line);
  border-radius: var(--radius-lg);
  background: var(--panel);
  overflow: hidden;
}

.model-bar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  padding: 0.75rem 1rem;
  border-bottom: 1px solid var(--line);
  background: var(--panel-2);
}

.model-label {
  font-family: var(--font-mono);
  font-size: var(--text-2xs);
  text-transform: uppercase;
  letter-spacing: 0.14em;
  color: var(--ink-faint);
}

.model-tag {
  font-family: var(--font-mono);
  font-size: var(--text-2xs);
  letter-spacing: 0.08em;
  color: var(--ink-faint);
  border: 1px solid var(--line-strong);
  border-radius: var(--radius);
  padding: 0.125rem 0.5rem;
  white-space: nowrap;
}

/* Trace-emphasis selector — an ARIA tablist, fully keyboard driven. */
.model-tabs {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  border-bottom: 1px solid var(--line);
}

.model-tab {
  padding: 0.8125rem 0.5rem;
  font-family: var(--font-mono);
  font-size: var(--text-2xs);
  text-transform: uppercase;
  letter-spacing: 0.1em;
  color: var(--ink-faint);
  border-right: 1px solid var(--line);
  transition:
    color var(--dur) var(--ease),
    background-color var(--dur) var(--ease);
  position: relative;
}

.model-tab:last-child {
  border-right: none;
}

.model-tab:hover {
  color: var(--ink-muted);
  background: var(--panel-2);
}

.model-tab[aria-selected='true'] {
  color: var(--ink);
  background: var(--panel-2);
}

.model-tab[aria-selected='true']::after {
  content: '';
  position: absolute;
  inset: auto 0 0 0;
  height: 2px;
  background: var(--accent);
}

.model-body {
  padding: 1.25rem 1rem 1rem;
}

.model-chart {
  position: relative;
}

.model-chart svg {
  width: 100%;
  height: auto;
  display: block;
  overflow: visible;
}

.chart-grid line {
  stroke: var(--line-faint);
  stroke-width: 1;
  vector-effect: non-scaling-stroke;
}

/* Six qualitative checkpoints, no numeric axis. Small so all six fit the row;
   sized in SVG user units, so they track the panel width. */
.chart-axis text {
  font-family: var(--font-mono);
  font-size: 6px;
  fill: var(--ink-faint);
  letter-spacing: 0.02em;
}

/* Inactive traces stay gray but readable (3:1 non-text minimum); only the
   emphasized trace takes the accent. */
.series {
  fill: none;
  stroke-width: 1.5;
  vector-effect: non-scaling-stroke;
  stroke-linecap: round;
  stroke-linejoin: round;
  stroke: var(--ink-muted);
  opacity: 0.75;
  transition:
    opacity var(--dur) var(--ease),
    stroke var(--dur) var(--ease);
}

.series.is-active {
  stroke: var(--accent);
  opacity: 1;
  stroke-width: 2;
}

.series-fill {
  fill: var(--accent-dim);
  opacity: 0;
  transition: opacity var(--dur) var(--ease);
}

.series-fill.is-active {
  opacity: 1;
}

/* Checkpoint markers — shown only on the emphasized trace. */
.series-dots circle {
  fill: var(--panel);
  stroke: var(--ink-muted);
  stroke-width: 1.25;
  vector-effect: non-scaling-stroke;
  opacity: 0;
  transition: opacity var(--dur) var(--ease);
}

.series-dots.is-active circle {
  opacity: 1;
  stroke: var(--accent);
}

.model-legend {
  display: flex;
  flex-wrap: wrap;
  gap: 0.875rem;
  margin-top: 0.875rem;
  padding-top: 0.875rem;
  border-top: 1px solid var(--line);
}

.legend-item {
  display: inline-flex;
  align-items: center;
  gap: 0.4375rem;
  font-family: var(--font-mono);
  font-size: var(--text-2xs);
  color: var(--ink-faint);
}

.legend-swatch {
  width: 12px;
  height: 2px;
  background: var(--ink-muted);
  flex: none;
}

.legend-item.is-active {
  color: var(--ink);
}

.legend-item.is-active .legend-swatch {
  background: var(--accent);
}

/* Anti-metric note under the legend. */
.model-note {
  margin-top: 0.75rem;
  font-family: var(--font-mono);
  font-size: var(--text-2xs);
  line-height: 1.5;
  color: var(--ink-faint);
}

/* DESIGN OBJECTIVES heading above the objective grid. */
.model-metrics-head {
  padding: 0.875rem 1rem 0.5rem;
  border-top: 1px solid var(--line);
  font-family: var(--font-mono);
  font-size: var(--text-2xs);
  text-transform: uppercase;
  letter-spacing: 0.14em;
  color: var(--ink-faint);
}

/* Objective grid — the old four-cell structure; values are status labels,
   not measured metrics. */
.model-metrics {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
}

.metric {
  padding: 0.875rem 1rem;
  border-right: 1px solid var(--line);
  border-bottom: 1px solid var(--line);
}

.metric:nth-child(2n) {
  border-right: none;
}

.metric:nth-last-child(-n + 2) {
  border-bottom: none;
}

.metric-label {
  font-family: var(--font-mono);
  font-size: var(--text-2xs);
  text-transform: uppercase;
  letter-spacing: 0.1em;
  color: var(--ink-faint);
  margin-bottom: 0.375rem;
}

.metric-value {
  font-family: var(--font-display);
  font-size: var(--text-xl);
  font-weight: 500;
  letter-spacing: -0.01em;
}

.metric-delta {
  font-family: var(--font-mono);
  font-size: var(--text-2xs);
  color: var(--ink-faint);
  margin-top: 0.125rem;
}

/* Status footer — provenance line + interface-concept label, with the relocated
   supporting caption above them. */
.model-foot {
  padding: 0.75rem 1rem;
  border-top: 1px solid var(--line);
  background: var(--panel-2);
  display: flex;
  flex-direction: column;
  gap: 0.625rem;
}

.model-caption {
  font-family: var(--font-mono);
  font-size: var(--text-2xs);
  line-height: 1.55;
  color: var(--ink-faint);
}

.model-foot-row {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 0.5rem 1rem;
  flex-wrap: wrap;
  padding-top: 0.625rem;
  border-top: 1px solid var(--line);
}

.provenance {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  font-family: var(--font-mono);
  font-size: var(--text-2xs);
  color: var(--ink-faint);
  letter-spacing: 0.06em;
}

.provenance-dot {
  width: 6px;
  height: 6px;
  border-radius: 50%;
  background: var(--accent);
  flex: none;
}

/* ---- Staged line draw (progressive enhancement) ----
   With .js the three traces start undrawn (a pathLength-normalized dashoffset);
   .is-drawn — added by main.js when the panel scrolls into view — draws them
   in, staggered. If main.js never loads the head-script fallback drops .js.
   Under reduced motion the graph renders complete immediately. Without JS,
   every trace, label, and objective stays visible. */
.js .model .series {
  stroke-dasharray: 1;
  stroke-dashoffset: 1;
}

.js .model.is-drawn .series {
  stroke-dashoffset: 0;
  transition: stroke-dashoffset 0.9s var(--ease);
}

.js .model.is-drawn [data-series='analysis'] {
  transition-delay: 0.15s;
}

.js .model.is-drawn [data-series='review'] {
  transition-delay: 0.3s;
}

@media (prefers-reduced-motion: reduce) {
  .js .model .series {
    stroke-dashoffset: 0;
    transition: none;
  }
}

/* --------------------------------------------------------------------------
   8. Credibility strip
   -------------------------------------------------------------------------- */

.capability-strip {
  border-top: 1px solid var(--line);
  border-bottom: 1px solid var(--line);
  padding-block: 1.5rem;
}

.capability-strip ul {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem 2rem;
  align-items: center;
}

.capability-strip li {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  font-family: var(--font-mono);
  font-size: var(--text-2xs);
  text-transform: uppercase;
  letter-spacing: 0.12em;
  color: var(--ink-faint);
}

.capability-strip li::before {
  content: '';
  width: 3px;
  height: 3px;
  background: var(--ink-faint);
  flex: none;
}

/* --------------------------------------------------------------------------
   9. Card grids
   -------------------------------------------------------------------------- */

.grid {
  display: grid;
  gap: 1px;
  background: var(--line);
  border: 1px solid var(--line);
  border-radius: var(--radius-lg);
  overflow: hidden;
}

/* Cards sit on a 1px gap over a hairline background — the grid lines are the
   borders, so panels read as a single ruled sheet rather than floating boxes. */
.grid-3 {
  grid-template-columns: repeat(3, minmax(0, 1fr));
}

.grid-2 {
  grid-template-columns: repeat(2, minmax(0, 1fr));
}

.card {
  background: var(--bg);
  padding: clamp(1.5rem, 2.5vw, 2rem);
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
  transition: background-color var(--dur) var(--ease);
}

.card:hover {
  background: var(--panel);
}

.card-index {
  font-family: var(--font-mono);
  font-size: var(--text-2xs);
  color: var(--ink-faint);
  letter-spacing: 0.1em;
}

.card-title {
  font-size: var(--text-xl);
  font-weight: 600;
}

.card-body {
  color: var(--ink-muted);
  font-size: var(--text-sm);
  line-height: 1.7;
}

/* The #approach method grid reads as four SEPARATE boxes rather than the shared
   ruled sheet: real gaps, no framing background/border/clip on the container,
   and a self-contained border + radius on each card. */
.method {
  gap: 1rem;
  background: none;
  border: none;
  border-radius: 0;
  overflow: visible;
}

.method .card {
  border: 1px solid var(--line);
  border-radius: var(--radius-lg);
}

/* --------------------------------------------------------------------------
   10. Product lines
   -------------------------------------------------------------------------- */

.product {
  background: var(--bg);
  padding: clamp(1.5rem, 2.5vw, 2rem);
  display: flex;
  flex-direction: column;
  gap: 1rem;
}

/* Stacked rather than inline: status labels vary a lot in length
   ("Available now" vs "Commercialization exploration"), so a shared row either
   overflows the card or aligns inconsistently between the three products. */
.product-head {
  display: flex;
  flex-direction: column;
  align-items: flex-start;
  gap: 0.625rem;
}

.product-title {
  font-size: var(--text-xl);
  font-weight: 600;
}

.status {
  flex: none;
  font-family: var(--font-mono);
  font-size: var(--text-2xs);
  text-transform: uppercase;
  letter-spacing: 0.1em;
  color: var(--ink-faint);
  border: 1px solid var(--line-strong);
  border-radius: var(--radius);
  padding: 0.1875rem 0.5rem;
  white-space: nowrap;
}

/* Availability is a functional signal, so it earns the accent. */
.status-available {
  color: var(--accent);
  border-color: var(--accent-line);
}

.product-body {
  color: var(--ink-muted);
  font-size: var(--text-sm);
  line-height: 1.7;
  flex: 1;
}

.product-foot {
  padding-top: 0.5rem;
}

/* Cards with a hover preview hint at it: a soft accent edge and a cursor that
   signals there is something to reveal. */
.product.has-preview {
  cursor: pointer;
  transition: background-color var(--dur) var(--ease);
}

.product.has-preview:hover,
.product.has-preview:focus-within {
  background: var(--panel);
}

/* Floating preview box. Rendered as a direct child of <body> (see main.js) so
   it escapes the products grid's `overflow: hidden` and the .reveal transform
   containing-block; positioned per-card with position: fixed. */
.product-preview {
  --arrow-x: 50%; /* horizontal arrow offset; JS overrides per card */
  position: fixed;
  z-index: 200;
  width: 360px;
  max-width: 88vw;
  border: 1px solid var(--line-strong);
  border-radius: var(--radius-lg);
  background: var(--panel);
  box-shadow: 0 18px 48px rgba(0, 0, 0, 0.55);
  overflow: hidden;
  opacity: 0;
  transform: translateY(6px);
  transition:
    opacity 0.18s var(--ease),
    transform 0.18s var(--ease);
  pointer-events: none; /* never intercept the hover that summoned it */
}

.product-preview.is-visible {
  opacity: 1;
  transform: translateY(0);
}

/* Little pointer joining the box to its card; JS sets --arrow-x and flips
   .points-down when the box sits above the card instead of below. */
.product-preview::after {
  content: '';
  position: absolute;
  left: var(--arrow-x, 50%);
  transform: translateX(-50%);
  border: 7px solid transparent;
}

.product-preview:not(.points-down)::after {
  bottom: 100%;
  border-bottom-color: var(--line-strong);
}

.product-preview.points-down::after {
  top: 100%;
  border-top-color: var(--line-strong);
}

.product-preview-media {
  display: block;
  width: 100%;
  height: auto;
  aspect-ratio: 16 / 9;
  object-fit: cover;
  background: var(--bg);
}

@media (prefers-reduced-motion: reduce) {
  .product-preview {
    transition: none;
    transform: none;
  }
}

/* --------------------------------------------------------------------------
   11. ReactorCast section
   -------------------------------------------------------------------------- */

.reactorcast {
  background: var(--panel);
  border-top: 1px solid var(--line);
  border-bottom: 1px solid var(--line);
}

/* The licensing-status notice: visible and unmissable, but not alarmist. */
.notice {
  display: flex;
  gap: 0.875rem;
  padding: 1rem 1.125rem;
  border: 1px solid var(--line-strong);
  border-left: 2px solid var(--accent);
  border-radius: var(--radius);
  background: var(--bg);
  margin-block: 1.75rem;
}

.notice-label {
  font-family: var(--font-mono);
  font-size: var(--text-2xs);
  text-transform: uppercase;
  letter-spacing: 0.12em;
  color: var(--accent);
  flex: none;
  padding-top: 0.125rem;
}

.notice p {
  font-size: var(--text-sm);
  line-height: 1.65;
  color: var(--ink-muted);
}

.subhead {
  font-family: var(--font-mono);
  font-size: var(--text-2xs);
  text-transform: uppercase;
  letter-spacing: 0.14em;
  color: var(--ink-faint);
  margin-bottom: 1rem;
}

/* Commercialization path — six stages presented as one ruled process. */
.rc-path {
  margin-top: clamp(2rem, 4vw, 3rem);
}

.rc-path-title {
  font-size: var(--text-2xl);
  margin-bottom: 0.875rem;
}

.rc-path-intro {
  color: var(--ink-muted);
  font-size: var(--text-lg);
  line-height: 1.7;
  max-width: 60rem;
  margin-bottom: clamp(1.75rem, 3vw, 2.5rem);
}

/* Ruled 3-up grid: shared hairlines make the stages read as one sequence
   rather than unrelated feature cards. Reflows to 2 then 1 column. */
.stage-grid {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 1px;
  background: var(--line);
  border: 1px solid var(--line);
  border-radius: var(--radius-lg);
  overflow: hidden;
}

.stage {
  background: var(--bg);
  padding: clamp(1.375rem, 2vw, 1.75rem);
  display: flex;
  flex-direction: column;
  gap: 0.625rem;
}

.stage-meta {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  margin-bottom: 0.125rem;
}

/* Two-digit stage number with a short accent progression tick beneath it —
   a restrained, always-visible progression cue that holds at every width. */
.stage-num {
  position: relative;
  font-family: var(--font-display);
  font-size: var(--text-xl);
  font-weight: 600;
  letter-spacing: -0.01em;
  color: var(--ink);
  font-variant-numeric: tabular-nums;
  padding-bottom: 0.375rem;
  flex: none;
}

.stage-num::after {
  content: '';
  position: absolute;
  left: 0;
  bottom: 0;
  width: 1.25rem;
  height: 2px;
  background: var(--accent);
}

/* Phase label — deliberately restrained so it never competes with the title. */
.stage-phase {
  font-family: var(--font-mono);
  font-size: var(--text-2xs);
  text-transform: uppercase;
  letter-spacing: 0.14em;
  color: var(--ink-faint);
}

.stage-title {
  font-family: var(--font-display);
  font-size: var(--text-lg);
  font-weight: 600;
  line-height: 1.25;
}

.stage-body {
  font-size: var(--text-sm);
  color: var(--ink-muted);
  line-height: 1.65;
}

/* Multidisciplinary-validation callout — collaborative framing, not a warning:
   a lighter panel with an accent edge, no icon. */
.callout {
  margin-top: clamp(1.75rem, 3vw, 2.5rem);
  padding: 1.25rem 1.5rem;
  border: 1px solid var(--line-strong);
  border-left: 2px solid var(--accent);
  border-radius: var(--radius);
  background: var(--panel-2);
}

.callout-label {
  font-family: var(--font-mono);
  font-size: var(--text-2xs);
  text-transform: uppercase;
  letter-spacing: 0.12em;
  color: var(--accent);
  margin-bottom: 0.5rem;
}

.callout-body {
  font-size: var(--text-sm);
  color: var(--ink-muted);
  line-height: 1.7;
  max-width: 62rem;
}

.rc-cta {
  margin-top: clamp(1.75rem, 3vw, 2.5rem);
}

/* --------------------------------------------------------------------------
   12. Commercialization method
   -------------------------------------------------------------------------- */

/* Bullet list inside the four method cards — dashed markers to match the
   institutional, engineering-drawing feel of the rest of the page. */
.method-list {
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
  margin-top: 0.25rem;
}

.method-list li {
  position: relative;
  padding-left: 1rem;
  font-size: var(--text-sm);
  color: var(--ink-muted);
  line-height: 1.5;
}

.method-list li::before {
  content: '';
  position: absolute;
  left: 0;
  top: 0.6em;
  width: 0.5rem;
  height: 1px;
  background: var(--line-strong);
}

/* --------------------------------------------------------------------------
   13. Company
   -------------------------------------------------------------------------- */

.company-grid {
  display: grid;
  grid-template-columns: minmax(0, 1.15fr) minmax(0, 1fr);
  gap: clamp(2rem, 5vw, 4rem);
  align-items: start;
}

.company-body p + p {
  margin-top: 1.125rem;
}

.company-body p {
  color: var(--ink-muted);
  line-height: 1.75;
}

.facts {
  border: 1px solid var(--line);
  border-radius: var(--radius-lg);
  overflow: hidden;
}

.facts div {
  display: flex;
  justify-content: space-between;
  gap: 1rem;
  padding: 0.8125rem 1rem;
  border-bottom: 1px solid var(--line);
  font-size: var(--text-sm);
}

.facts div:last-child {
  border-bottom: none;
}

.facts dt {
  font-family: var(--font-mono);
  font-size: var(--text-2xs);
  text-transform: uppercase;
  letter-spacing: 0.1em;
  color: var(--ink-faint);
  padding-top: 0.1875rem;
}

.facts dd {
  margin: 0;
  text-align: right;
  color: var(--ink);
}

.tags {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
  margin-top: 1.75rem;
}

.tag {
  font-family: var(--font-mono);
  font-size: var(--text-2xs);
  letter-spacing: 0.06em;
  color: var(--ink-muted);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 0.25rem 0.5625rem;
}

/* --------------------------------------------------------------------------
   14. FAQ — native <details> for free keyboard and screen-reader support
   -------------------------------------------------------------------------- */

.faq {
  border: 1px solid var(--line);
  border-radius: var(--radius-lg);
  overflow: hidden;
  max-width: 52rem;
}

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

.faq details:last-child {
  border-bottom: none;
}

.faq summary {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1.5rem;
  padding: 1.125rem 1.25rem;
  cursor: pointer;
  list-style: none;
  font-family: var(--font-display);
  font-size: var(--text-base);
  font-weight: 500;
  transition: background-color var(--dur) var(--ease);
}

.faq summary::-webkit-details-marker {
  display: none;
}

.faq summary:hover {
  background: var(--panel);
}

.faq summary::after {
  content: '';
  flex: none;
  width: 9px;
  height: 9px;
  border-right: 1px solid var(--ink-faint);
  border-bottom: 1px solid var(--ink-faint);
  transform: rotate(45deg) translateY(-2px);
  transition: transform var(--dur) var(--ease);
}

.faq details[open] summary::after {
  transform: rotate(-135deg) translateY(-2px);
}

.faq-answer {
  padding: 0 1.25rem 1.25rem;
  color: var(--ink-muted);
  font-size: var(--text-sm);
  line-height: 1.75;
  max-width: 46rem;
}

.faq-answer p + p {
  margin-top: 0.875rem;
}

/* --------------------------------------------------------------------------
   15. Contact
   -------------------------------------------------------------------------- */

.contact-grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr) minmax(0, 1fr);
  gap: clamp(2rem, 5vw, 4rem);
  align-items: start;
}

/* Investor/licensing statement above the interest lists. */
.contact-statement {
  color: var(--ink-muted);
  font-size: var(--text-lg);
  line-height: 1.7;
  margin-bottom: 1.75rem;
}

/* Space the second heading (Areas of interest) away from the list above it. */
.interest-list + .subhead {
  margin-top: 1.75rem;
}

.interest-list li {
  padding-block: 0.6875rem;
  border-bottom: 1px solid var(--line);
  font-size: var(--text-sm);
  color: var(--ink-muted);
  display: flex;
  align-items: center;
  gap: 0.75rem;
}

.interest-list li::before {
  content: '';
  width: 4px;
  height: 4px;
  border: 1px solid var(--ink-faint);
  flex: none;
  transform: rotate(45deg);
}

.contact-card {
  border: 1px solid var(--line);
  border-radius: var(--radius-lg);
  padding: clamp(1.5rem, 3vw, 2rem);
  background: var(--panel);
  display: flex;
  flex-direction: column;
  gap: 1.25rem;
}

.contact-email {
  font-family: var(--font-display);
  font-size: var(--text-xl);
  font-weight: 500;
  word-break: break-word;
  border-bottom: 1px solid var(--line-strong);
  padding-bottom: 0.25rem;
  align-self: flex-start;
  transition: border-color var(--dur) var(--ease);
}

.contact-email:hover {
  border-bottom-color: var(--accent);
}

.contact-meta {
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
  padding-top: 1.25rem;
  border-top: 1px solid var(--line);
  font-family: var(--font-mono);
  font-size: var(--text-2xs);
  color: var(--ink-faint);
  letter-spacing: 0.06em;
}

/* --------------------------------------------------------------------------
   16. Footer
   -------------------------------------------------------------------------- */

.site-footer {
  border-top: 1px solid var(--line);
  padding-block: clamp(2.5rem, 5vw, 4rem) 2rem;
}

.footer-grid {
  display: grid;
  grid-template-columns: minmax(0, 1.5fr) repeat(3, minmax(0, 1fr));
  gap: 2.5rem;
  padding-bottom: 2.5rem;
  border-bottom: 1px solid var(--line);
}

.footer-about p {
  margin-top: 0.875rem;
  color: var(--ink-muted);
  font-size: var(--text-sm);
  line-height: 1.7;
  max-width: 22rem;
}

.footer-heading {
  font-family: var(--font-mono);
  font-size: var(--text-2xs);
  text-transform: uppercase;
  letter-spacing: 0.14em;
  color: var(--ink-faint);
  margin-bottom: 0.875rem;
}

.footer-links li {
  margin-bottom: 0.5rem;
}

.footer-links a {
  font-size: var(--text-sm);
  color: var(--ink-muted);
  transition: color var(--dur) var(--ease);
}

.footer-links a:hover {
  color: var(--ink);
}

.footer-bottom {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  padding-top: 1.75rem;
  font-family: var(--font-mono);
  font-size: var(--text-2xs);
  color: var(--ink-faint);
  letter-spacing: 0.06em;
}

/* Sub-pages carry no footer columns, so the bottom bar provides the
   cross-links between Privacy, Terms, and home. */
.footer-legal {
  display: inline-flex;
  flex-wrap: wrap;
  gap: 1.25rem;
}

.footer-legal a {
  transition: color var(--dur) var(--ease);
}

.footer-legal a:hover {
  color: var(--ink);
}

/* --------------------------------------------------------------------------
   17. Legal / 404 pages
   -------------------------------------------------------------------------- */

.page-header {
  padding-block: clamp(3rem, 7vw, 5rem) clamp(2rem, 4vw, 3rem);
  border-bottom: 1px solid var(--line);
}

.page-title {
  font-size: var(--text-3xl);
  margin-top: 1rem;
}

.prose {
  max-width: var(--content-narrow);
  padding-block: clamp(2.5rem, 5vw, 4rem);
}

.prose h2 {
  font-size: var(--text-xl);
  margin-top: 2.5rem;
  margin-bottom: 0.875rem;
}

.prose h2:first-child {
  margin-top: 0;
}

.prose p,
.prose li {
  color: var(--ink-muted);
  font-size: var(--text-sm);
  line-height: 1.8;
}

.prose p + p {
  margin-top: 1rem;
}

.prose ul {
  list-style: disc;
  padding-left: 1.25rem;
  margin-top: 0.875rem;
}

.prose li {
  margin-bottom: 0.5rem;
}

.prose a {
  border-bottom: 1px solid var(--line-strong);
}

.prose a:hover {
  border-bottom-color: var(--ink);
}

.error-page {
  min-height: 60vh;
  display: flex;
  flex-direction: column;
  justify-content: center;
  gap: 1.25rem;
  padding-block: clamp(4rem, 10vw, 8rem);
  max-width: 34rem;
}

.error-code {
  font-family: var(--font-mono);
  font-size: var(--text-2xs);
  letter-spacing: 0.2em;
  color: var(--ink-faint);
  text-transform: uppercase;
}

/* --------------------------------------------------------------------------
   18. Motion — opt-in reveal, disabled entirely under reduced-motion
   -------------------------------------------------------------------------- */

/* Scoped to .js so that with scripting disabled the content is simply visible
   rather than stuck at opacity 0. */
.js .reveal {
  opacity: 0;
  transform: translateY(12px);
  transition:
    opacity 600ms var(--ease),
    transform 600ms var(--ease);
}

.js .reveal.is-visible {
  opacity: 1;
  transform: none;
}

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

  *,
  *::before,
  *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
    scroll-behavior: auto !important;
  }

  .js .reveal {
    opacity: 1;
    transform: none;
    transition: none;
  }
}

/* --------------------------------------------------------------------------
   19. Responsive
   -------------------------------------------------------------------------- */

@media (max-width: 1080px) {
  .stage-grid {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
}

/* 1060px, not 940px: the seven nav links plus the CTA and the brand need about
   975px of header width, so below ~1053px the links wrap inside the fixed-height
   bar and the CTA is pushed off-screen. Keep main.js's matchMedia in sync. */
@media (max-width: 1060px) {
  .hero-grid,
  .company-grid,
  .contact-grid {
    grid-template-columns: minmax(0, 1fr);
  }

  .hero-copy {
    max-width: 40rem;
  }

  .grid-3 {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

  .footer-grid {
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 2rem;
  }

  /* Nav collapses into a disclosure panel below the header bar. */
  .nav-toggle {
    display: inline-flex;
  }

  .nav {
    display: none;
    position: absolute;
    top: 100%;
    left: 0;
    right: 0;
    flex-direction: column;
    align-items: stretch;
    gap: 0;
    padding: 0.5rem var(--space-gutter) 1.25rem;
    background: var(--bg);
    border-bottom: 1px solid var(--line);
    margin-left: 0;
  }

  .nav.is-open {
    display: flex;
  }

  .nav-link {
    padding: 0.8125rem 0;
    border-bottom: 1px solid var(--line);
    font-size: var(--text-base);
  }

  .nav-link[aria-current='true']::after {
    left: 0;
    right: auto;
    width: 1.25rem;
    bottom: 0.4rem;
  }

  .nav-cta {
    margin-left: 0;
    margin-top: 1rem;
  }
}

@media (max-width: 720px) {
  .stage-grid,
  .grid-3,
  .grid-2 {
    grid-template-columns: minmax(0, 1fr);
  }

  .model-metrics {
    grid-template-columns: minmax(0, 1fr);
  }

  .metric {
    border-right: none;
  }

  .metric:nth-last-child(-n + 2) {
    border-bottom: 1px solid var(--line);
  }

  .metric:last-child {
    border-bottom: none;
  }

  .btn-row .btn {
    flex: 1 1 100%;
  }

  .facts div {
    flex-direction: column;
    gap: 0.25rem;
  }

  .facts dd {
    text-align: left;
  }
}

@media (max-width: 560px) {
  .footer-grid {
    grid-template-columns: minmax(0, 1fr);
  }

  .rail::before,
  .rail::after {
    display: none;
  }

  .model-tabs {
    grid-template-columns: minmax(0, 1fr);
  }

  .model-tab {
    border-right: none;
    border-bottom: 1px solid var(--line);
    text-align: left;
    padding-inline: 1rem;
  }

  .model-tab:last-child {
    border-bottom: none;
  }

  .model-tab[aria-selected='true']::after {
    inset: 0 auto 0 0;
    width: 2px;
    height: auto;
  }
}

/* --------------------------------------------------------------------------
   20. Print
   -------------------------------------------------------------------------- */

@media print {
  /* Re-point the tokens rather than patching each consumer: every muted colour
     is tuned for a near-black background and would sit at ~2.8:1 on paper. */
  :root {
    --bg: #fff;
    --panel: #fff;
    --panel-2: #fff;
    --panel-3: #fff;
    --ink: #000;
    --ink-muted: #333;
    --ink-faint: #555;
    --accent: #000;
    --accent-dim: transparent;
    --accent-line: #999;
    --line: #ccc;
    --line-strong: #999;
    --line-faint: #ddd;
  }

  .site-header,
  .nav-toggle,
  .model-tabs,
  .skip-link {
    display: none;
  }

  body {
    background: #fff;
    color: #000;
  }
}