/* ==========================================================================
   ESUMEI — design tokens
   "Control panel / schematic sheet" system: editorial sans headlines +
   monospace technical labels, dark industrial base, one signal accent
   (orange) and one telemetry accent (teal), used sparingly.
   ========================================================================== */
:root {
  --color-bg: #0a0d11;
  --color-bg-alt: #0f1319;
  --color-surface: #141a21;
  --color-surface-raised: #1a212a;
  --color-border: #262e38;
  --color-border-strong: #37424f;
  --color-text: #edf1f5;
  --color-text-muted: #a7b5c2;
  --color-text-faint: #778693;

  --color-accent: #f2803f;
  --color-accent-strong: #ff9757;
  --color-accent-contrast: #1a0f07;
  --color-signal: #4fc7c0;
  --color-signal-strong: #7fe0d9;

  --color-focus: #6fb8ff;
  --color-ok: #3fb87f;
  --color-error: #ff6b6b;

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

  --fs-100: 0.8125rem;
  --fs-200: 0.9375rem;
  --fs-300: 1rem;
  --fs-400: 1.125rem;
  --fs-500: 1.375rem;
  --fs-600: 1.9rem;
  --fs-700: 3rem;
  --fs-800: 4.25rem;
  --fs-900: 5.5rem;

  --line-height-base: 1.55;
  --line-height-tight: 1.05;

  --space-1: 0.25rem;
  --space-2: 0.5rem;
  --space-3: 0.75rem;
  --space-4: 1rem;
  --space-5: 1.5rem;
  --space-6: 2rem;
  --space-7: 3rem;
  --space-8: 4.5rem;
  --space-9: 6.5rem;

  --radius-sm: 3px;
  --radius-md: 6px;
  --radius-lg: 10px;

  --shadow-card: 0 1px 2px rgba(0, 0, 0, 0.45), 0 10px 28px rgba(0, 0, 0, 0.3);
  --shadow-panel: 0 20px 60px rgba(0, 0, 0, 0.45);

  --container-max: 1220px;
  --nav-height: 96px;

  --grid-line: rgba(167, 181, 194, 0.06);
  --grid-line-strong: rgba(79, 199, 192, 0.1);

  color-scheme: dark;
}

/* ==========================================================================
   Reset / base
   ========================================================================== */
*,
*::before,
*::after {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
  scroll-padding-top: var(--nav-height);
}

body {
  margin: 0;
  background: var(--color-bg);
  color: var(--color-text);
  font-family: var(--font-sans);
  font-size: var(--fs-300);
  line-height: var(--line-height-base);
  -webkit-font-smoothing: antialiased;
}

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

a {
  color: var(--color-accent-strong);
}

a:hover {
  color: var(--color-accent);
}

button {
  font: inherit;
}

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

h1, h2, h3, h4 {
  line-height: var(--line-height-tight);
  margin: 0 0 var(--space-3);
  font-weight: 800;
  letter-spacing: -0.015em;
}

h1 { font-size: var(--fs-900); }
h2 { font-size: var(--fs-700); }
h3 { font-size: var(--fs-400); }

p {
  margin: 0 0 var(--space-4);
  color: var(--color-text);
}

table {
  border-collapse: collapse;
  width: 100%;
}

code {
  font-family: var(--font-mono);
}

:focus-visible {
  outline: 3px solid var(--color-focus);
  outline-offset: 2px;
}

@media (prefers-reduced-motion: reduce) {
  html {
    scroll-behavior: auto;
  }
  *,
  *::before,
  *::after {
    animation-duration: 0.001ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.001ms !important;
    scroll-behavior: auto !important;
  }
}

/* ==========================================================================
   Layout / utility
   ========================================================================== */
.container {
  width: 100%;
  max-width: var(--container-max);
  margin-inline: auto;
  padding-inline: var(--space-5);
}

.section {
  position: relative;
  padding-block: var(--space-9) var(--space-8);
}

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

.section-header {
  max-width: 780px;
  margin-bottom: var(--space-7);
  position: relative;
}

.section-index {
  display: flex;
  align-items: baseline;
  gap: var(--space-3);
  margin-bottom: var(--space-4);
}

.section-index .index-number {
  font-family: var(--font-mono);
  font-size: var(--fs-300);
  font-weight: 700;
  color: var(--color-signal);
  letter-spacing: 0.02em;
}

.section-index .eyebrow {
  font-family: var(--font-mono);
  font-size: var(--fs-100);
  font-weight: 700;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--color-text-faint);
}

.lede {
  color: var(--color-text-muted);
  font-size: var(--fs-400);
  max-width: 64ch;
}

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

.skip-link {
  position: absolute;
  top: -60px;
  left: var(--space-4);
  z-index: 1000;
  background: var(--color-accent);
  color: var(--color-accent-contrast);
  padding: var(--space-3) var(--space-4);
  border-radius: var(--radius-sm);
  font-weight: 700;
  transition: top 0.15s ease;
}

.skip-link:focus {
  top: var(--space-4);
}

.note {
  font-size: var(--fs-200);
  color: var(--color-text-faint);
  border-left: 2px solid var(--color-border-strong);
  padding-left: var(--space-4);
}

.badge-placeholder {
  display: inline-block;
  padding: var(--space-1) var(--space-3);
  border: 1px solid var(--color-border-strong);
  border-radius: 999px;
  font-family: var(--font-mono);
  font-size: var(--fs-100);
  color: var(--color-text-muted);
  background: var(--color-surface);
}

/* Faint blueprint grid background — pure CSS, no image request */
.tech-grid {
  background-image:
    linear-gradient(var(--grid-line) 1px, transparent 1px),
    linear-gradient(90deg, var(--grid-line) 1px, transparent 1px);
  background-size: 44px 44px;
  background-position: center top;
}

/* Signal ruler — tick-marked divider between bands, replaces plain hairlines */
.signal-ruler {
  height: 1px;
  background-image: repeating-linear-gradient(
    90deg,
    var(--color-border-strong) 0,
    var(--color-border-strong) 1px,
    transparent 1px,
    transparent 12px
  );
  position: relative;
}

.signal-ruler::after {
  content: "";
  position: absolute;
  inset: 0;
  background: linear-gradient(90deg, transparent, var(--color-signal) 50%, transparent);
  opacity: 0.35;
}

/* Bracket-cornered panel frame, used on device illustration + spec blocks */
.bracket-panel {
  position: relative;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  background: var(--color-surface);
}

.bracket-panel::before,
.bracket-panel::after,
.bracket-panel .corner-tl,
.bracket-panel .corner-br {
  content: "";
  position: absolute;
  width: 18px;
  height: 18px;
  border-color: var(--color-signal);
  opacity: 0.7;
}

.bracket-panel::before {
  top: -1px;
  left: -1px;
  border-top: 2px solid var(--color-signal);
  border-left: 2px solid var(--color-signal);
}

.bracket-panel::after {
  bottom: -1px;
  right: -1px;
  border-bottom: 2px solid var(--color-signal);
  border-right: 2px solid var(--color-signal);
}

/* ==========================================================================
   Buttons
   ========================================================================== */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-2);
  padding: var(--space-3) var(--space-5);
  border-radius: var(--radius-sm);
  border: 1px solid transparent;
  font-weight: 700;
  font-size: var(--fs-300);
  cursor: pointer;
  text-decoration: none;
  transition: background-color 0.15s ease, border-color 0.15s ease, color 0.15s ease, transform 0.1s ease;
}

.btn-primary {
  background: var(--color-accent);
  color: var(--color-accent-contrast);
}

.btn-primary:hover {
  background: var(--color-accent-strong);
  color: var(--color-accent-contrast);
}

.btn-secondary {
  background: transparent;
  color: var(--color-text);
  border-color: var(--color-border-strong);
}

.btn-secondary:hover {
  border-color: var(--color-signal);
  color: var(--color-signal-strong);
}

.btn-small {
  padding: var(--space-2) var(--space-4);
  font-size: var(--fs-200);
}

.btn[disabled] {
  opacity: 0.5;
  cursor: not-allowed;
}

.btn:active {
  transform: translateY(1px);
}

/* ==========================================================================
   Header / nav
   ========================================================================== */
.site-header {
  position: sticky;
  top: 0;
  z-index: 100;
  height: var(--nav-height);
  display: flex;
  align-items: center;
  background: rgba(10, 13, 17, 0.9);
  backdrop-filter: saturate(140%) blur(8px);
  border-bottom: 1px solid var(--color-border);
}

.site-header .container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-4);
}

.brand {
  display: flex;
  align-items: center;
  gap: var(--space-2);
}

.brand img {
  height: 80px;
  width: auto;
}

.nav-toggle {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 44px;
  height: 44px;
  background: transparent;
  border: 1px solid var(--color-border-strong);
  border-radius: var(--radius-sm);
  color: var(--color-text);
  cursor: pointer;
}

.nav-toggle svg {
  width: 22px;
  height: 22px;
}

.nav-toggle .icon-close {
  display: none;
}

.nav-toggle[aria-expanded="true"] .icon-menu {
  display: none;
}

.nav-toggle[aria-expanded="true"] .icon-close {
  display: block;
}

.primary-nav {
  position: fixed;
  inset: var(--nav-height) 0 0 0;
  background: var(--color-bg);
  padding: var(--space-5);
  overflow-y: auto;
  transform: translateY(-8px);
  opacity: 0;
  pointer-events: none;
  transition: opacity 0.15s ease, transform 0.15s ease;
}

.primary-nav.is-open {
  opacity: 1;
  transform: translateY(0);
  pointer-events: auto;
}

.primary-nav > ul {
  counter-reset: navstep;
  display: flex;
  flex-direction: column;
  gap: var(--space-1);
}

.primary-nav > ul > li {
  counter-increment: navstep;
}

/* Only the four top-level items get numbered — nested dropdown links do not.
   summary is a grandchild of li (li > details > summary), hence the
   descendant combinator here; there is no other summary element anywhere
   in .primary-nav for it to accidentally match. */
.primary-nav > ul > li > a::before,
.primary-nav > ul > li summary::before {
  content: counter(navstep, decimal-leading-zero) " ";
  font-family: var(--font-mono);
  color: var(--color-signal);
  margin-right: var(--space-2);
  font-size: 0.85em;
}

.primary-nav a {
  display: block;
  width: 100%;
  text-align: left;
  padding: var(--space-4) var(--space-2);
  color: var(--color-text);
  text-decoration: none;
  font-weight: 700;
  font-size: var(--fs-500);
  border-bottom: 1px solid var(--color-border);
}

.primary-nav a:hover {
  color: var(--color-accent-strong);
}

.nav-cta {
  display: inline-flex;
  margin-top: var(--space-5);
}

/* Products / Bundles dropdown — native <details>/<summary>, works without JS */
.nav-dropdown {
  border-bottom: 1px solid var(--color-border);
}

.nav-dropdown summary {
  cursor: pointer;
  list-style: none;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-2);
  padding: var(--space-4) var(--space-2);
  color: var(--color-text);
  font-weight: 700;
  font-size: var(--fs-500);
}

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

.nav-dropdown summary .chevron {
  width: 14px;
  height: 14px;
  flex-shrink: 0;
  transition: transform 0.15s ease;
}

.nav-dropdown[open] summary .chevron {
  transform: rotate(180deg);
}

.nav-dropdown summary:hover {
  color: var(--color-accent-strong);
}

.nav-dropdown-menu {
  padding: 0 0 var(--space-2) var(--space-5);
}

.nav-dropdown-menu a {
  border-bottom: none;
  padding: var(--space-3) var(--space-2);
  font-size: var(--fs-400);
  font-weight: 500;
  color: var(--color-text-muted);
}

.nav-dropdown-menu a:hover {
  color: var(--color-accent-strong);
}

/* ==========================================================================
   Hero
   ========================================================================== */
.hero {
  padding-block: var(--space-8) var(--space-7);
  position: relative;
  overflow: hidden;
}

.hero::before {
  content: "";
  position: absolute;
  inset: 0;
  background:
    radial-gradient(55% 55% at 82% 12%, rgba(242, 128, 63, 0.1), transparent 70%),
    radial-gradient(40% 40% at 10% 90%, rgba(79, 199, 192, 0.07), transparent 70%);
  pointer-events: none;
}

.hero .container {
  position: relative;
  display: grid;
  gap: var(--space-7);
  align-items: center;
}

.hero-index {
  font-family: var(--font-mono);
  color: var(--color-text-faint);
  font-size: var(--fs-200);
  margin-bottom: var(--space-3);
}

.hero-index strong {
  color: var(--color-signal);
}

.hero-eyebrow {
  display: inline-block;
  margin-bottom: var(--space-3);
  color: var(--color-accent-strong);
  font-family: var(--font-mono);
  font-size: var(--fs-100);
  font-weight: 700;
  letter-spacing: 0.12em;
  text-transform: uppercase;
}

.hero h1 {
  font-size: clamp(3rem, 11vw, var(--fs-900));
  margin-bottom: var(--space-4);
}

.hero .lede {
  font-size: var(--fs-400);
  max-width: 56ch;
}

.hero-actions {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-3);
  margin-top: var(--space-5);
}

.hero-stats {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-6);
  margin-top: var(--space-7);
  padding-top: var(--space-5);
  border-top: 1px solid var(--color-border);
}

.hero-stat .stat-value {
  display: block;
  font-family: var(--font-mono);
  font-size: var(--fs-500);
  font-weight: 700;
  color: var(--color-signal-strong);
}

.hero-stat .stat-label {
  display: block;
  font-size: var(--fs-100);
  color: var(--color-text-faint);
  text-transform: uppercase;
  letter-spacing: 0.06em;
  margin-top: var(--space-1);
}

/* Device illustration panel */
.device-panel {
  position: relative;
  padding: var(--space-6);
  min-height: 320px;
}

.device-panel .tech-grid {
  position: absolute;
  inset: 0;
  border-radius: inherit;
}

.device-illustration {
  position: relative;
  z-index: 1;
  color: var(--color-text-muted);
}

.device-illustration img {
  width: 100%;
  height: auto;
  display: block;
}

.device-illustration .accent {
  color: var(--color-accent);
}

.device-illustration .signal {
  color: var(--color-signal);
}

.device-callout {
  position: absolute;
  z-index: 2;
  display: flex;
  align-items: center;
  gap: var(--space-2);
  font-family: var(--font-mono);
  font-size: var(--fs-100);
  color: var(--color-text);
  background: rgba(10, 13, 17, 0.85);
  border: 1px solid var(--color-border-strong);
  border-radius: 999px;
  padding: var(--space-1) var(--space-3);
  white-space: nowrap;
}

.device-callout .dot {
  width: 6px;
  height: 6px;
  border-radius: 50%;
  background: var(--color-signal);
  flex-shrink: 0;
}

.device-callout.callout-lcd { top: 12%; left: 4%; }
.device-callout.callout-status { top: 8%; right: 6%; }
.device-callout.callout-hv { bottom: 14%; left: 6%; }
.device-callout.callout-usb { bottom: 6%; right: 10%; }

@media (prefers-reduced-motion: no-preference) {
  .device-callout .dot {
    animation: pulse-dot 2.4s ease-in-out infinite;
  }
}

@keyframes pulse-dot {
  0%, 100% { opacity: 0.5; transform: scale(0.85); }
  50% { opacity: 1; transform: scale(1.15); }
}

/* ==========================================================================
   Cards / grids
   ========================================================================== */
.grid {
  display: grid;
  gap: var(--space-5);
}

.grid-2 { grid-template-columns: 1fr; }
.grid-3 { grid-template-columns: 1fr; }

.card {
  position: relative;
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  padding: var(--space-5);
  box-shadow: var(--shadow-card);
  display: flex;
  flex-direction: column;
  gap: var(--space-3);
  transition: border-color 0.15s ease, transform 0.15s ease;
}

.card::before {
  content: "";
  position: absolute;
  top: -1px;
  left: var(--space-5);
  width: 28px;
  height: 2px;
  background: var(--color-accent);
}

.card:hover {
  border-color: var(--color-border-strong);
}

.card.is-featured {
  border-color: var(--color-accent);
  box-shadow: var(--shadow-panel);
}

.card.is-featured::before {
  background: var(--color-signal);
}

.card h3 {
  margin-bottom: 0;
}

.card .card-meta {
  font-family: var(--font-mono);
  font-size: var(--fs-100);
  color: var(--color-signal);
  text-transform: uppercase;
  letter-spacing: 0.08em;
  font-weight: 700;
}

.card p {
  color: var(--color-text-muted);
  margin-bottom: 0;
}

.card-actions {
  margin-top: auto;
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-2);
  padding-top: var(--space-3);
}

/* ==========================================================================
   Product tabs (progressive enhancement over stacked-panel fallback)
   ========================================================================== */
.tabs {
  margin-top: var(--space-6);
}

.tab-list {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-2);
  margin-bottom: var(--space-6);
  padding-bottom: var(--space-4);
}

.tab-label {
  display: inline-flex;
  align-items: center;
  gap: var(--space-2);
  padding: var(--space-2) var(--space-4);
  border: 1px solid var(--color-border-strong);
  border-radius: 999px;
  cursor: pointer;
  background: transparent;
  color: var(--color-text-muted);
  font-family: var(--font-mono);
  font-weight: 600;
  font-size: var(--fs-200);
}

.tab-label:hover {
  color: var(--color-text);
  border-color: var(--color-signal);
}

.tab-panel {
  display: block;
  margin-bottom: var(--space-7);
}

.tab-panel:last-child {
  margin-bottom: 0;
}

.tab-panel-title {
  color: var(--color-accent-strong);
  font-family: var(--font-mono);
  font-size: var(--fs-200);
  text-transform: uppercase;
  letter-spacing: 0.08em;
}

html.has-js .tab-list {
  display: flex;
}

html.has-js .tab-panel {
  display: none;
  margin-bottom: 0;
}

html.has-js .tab-panel.is-active {
  display: block;
}

html:not(.has-js) .tab-list {
  display: none;
}

.tab-label[aria-selected="true"] {
  background: var(--color-accent);
  border-color: var(--color-accent);
  color: var(--color-accent-contrast);
}

/* ==========================================================================
   Architecture flow diagram
   ========================================================================== */
.flow {
  counter-reset: flowstep;
  display: flex;
  flex-direction: column;
  gap: 0;
  margin-top: var(--space-7);
}

.flow-node {
  counter-increment: flowstep;
  position: relative;
  display: flex;
  gap: var(--space-4);
  align-items: flex-start;
  padding-block: var(--space-4);
}

.flow-node-marker {
  flex-shrink: 0;
  width: 52px;
  height: 52px;
  border-radius: 50%;
  border: 1px solid var(--color-border-strong);
  background: var(--color-surface);
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--color-signal);
  position: relative;
  z-index: 1;
}

.flow-node-marker svg {
  width: 24px;
  height: 24px;
}

.flow-node:not(:last-child)::before {
  content: "";
  position: absolute;
  left: 25px;
  top: 52px;
  bottom: -8px;
  width: 2px;
  background: repeating-linear-gradient(
    180deg,
    var(--color-border-strong) 0,
    var(--color-border-strong) 6px,
    transparent 6px,
    transparent 12px
  );
}

@media (prefers-reduced-motion: no-preference) {
  .flow-node:not(:last-child)::after {
    content: "";
    position: absolute;
    left: 24px;
    top: 52px;
    bottom: -8px;
    width: 4px;
    background: linear-gradient(180deg, transparent, var(--color-signal) 45%, transparent);
    background-size: 100% 200%;
    animation: flow-signal 3.2s linear infinite;
    opacity: 0.8;
  }
}

@keyframes flow-signal {
  0% { background-position: 0 -140%; }
  100% { background-position: 0 140%; }
}

.flow-node-body {
  padding-top: var(--space-1);
}

.flow-node-label {
  font-family: var(--font-mono);
  font-size: var(--fs-100);
  color: var(--color-text-faint);
  text-transform: uppercase;
  letter-spacing: 0.06em;
  margin-bottom: var(--space-1);
}

.flow-node-label::before {
  content: counter(flowstep, decimal-leading-zero) " — ";
  color: var(--color-signal);
}

.flow-node-body h3 {
  font-size: var(--fs-400);
  margin-bottom: var(--space-1);
}

.flow-node-body p {
  color: var(--color-text-muted);
  margin-bottom: 0;
  max-width: 56ch;
}

/* ==========================================================================
   Specification "readout" panels
   ========================================================================== */
.spec-groups {
  display: grid;
  gap: var(--space-5);
  margin-bottom: var(--space-7);
}

.spec-groups:last-child {
  margin-bottom: 0;
}

.spec-model-heading {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  gap: var(--space-3);
  margin-bottom: var(--space-5);
  padding-bottom: var(--space-3);
}

.spec-model-heading h3 {
  margin-bottom: 0;
}

.spec-model-heading .badge-placeholder {
  font-size: var(--fs-100);
}

.spec-panel {
  position: relative;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  background: var(--color-surface);
  padding: var(--space-4) var(--space-5) var(--space-2);
}

.spec-panel h4 {
  font-family: var(--font-mono);
  font-size: var(--fs-100);
  text-transform: uppercase;
  letter-spacing: 0.1em;
  color: var(--color-signal);
  margin-bottom: var(--space-3);
}

.spec-table {
  font-size: var(--fs-200);
}

.spec-table th,
.spec-table td {
  text-align: left;
  padding: var(--space-3) 0;
  border-bottom: 1px solid var(--color-border);
  vertical-align: top;
}

.spec-table tr:last-child th,
.spec-table tr:last-child td {
  border-bottom: none;
}

.spec-table th {
  width: 40%;
  color: var(--color-text-faint);
  font-family: var(--font-mono);
  font-weight: 500;
  font-size: 0.9em;
  text-transform: uppercase;
  letter-spacing: 0.03em;
}

.spec-table td {
  font-weight: 600;
  color: var(--color-text);
}

/* Product-photo detail crops (controlled crops, not the full photo repeated) */
.detail-grid {
  display: grid;
  gap: var(--space-4);
  margin: var(--space-6) 0;
}

.detail-card {
  margin: 0;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  overflow: hidden;
  background: var(--color-surface);
}

.detail-card img {
  width: 100%;
  height: auto;
  display: block;
}

.detail-card figcaption {
  padding: var(--space-3) var(--space-4);
  font-family: var(--font-mono);
  font-size: var(--fs-100);
  color: var(--color-text-faint);
  text-transform: uppercase;
  letter-spacing: 0.06em;
  border-top: 1px solid var(--color-border);
}

/* Expandable spec details — native <details>/<summary>, no JS required */
.spec-details {
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  background: var(--color-surface);
  padding: 0 var(--space-5);
  margin-top: var(--space-5);
}

.spec-details summary {
  cursor: pointer;
  list-style: none;
  padding: var(--space-4) 0;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-3);
  font-family: var(--font-mono);
  font-size: var(--fs-200);
  font-weight: 700;
  color: var(--color-signal);
  text-transform: uppercase;
  letter-spacing: 0.06em;
}

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

.spec-details summary::after {
  content: "+";
  font-family: var(--font-mono);
  font-size: 1.3em;
  color: var(--color-text-faint);
  transition: transform 0.15s ease;
}

.spec-details[open] summary::after {
  transform: rotate(45deg);
}

.spec-details .spec-groups {
  padding-bottom: var(--space-5);
  margin-bottom: 0;
}

/* Wide-table scroll container — wide content scrolls in its own box,
   the page itself never scrolls horizontally */
.table-scroll {
  overflow-x: auto;
  padding-bottom: var(--space-5);
}

.compare-table {
  width: 100%;
  min-width: 620px;
  border-collapse: collapse;
  font-size: var(--fs-200);
}

.compare-table th,
.compare-table td {
  padding: var(--space-3) var(--space-4);
  border-bottom: 1px solid var(--color-border);
  text-align: center;
  white-space: nowrap;
}

.compare-table thead th {
  font-family: var(--font-mono);
  font-size: var(--fs-100);
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: var(--color-text-faint);
}

.compare-table thead th:first-child {
  text-align: left;
}

.compare-table thead th:not(:first-child) {
  color: var(--color-signal);
}

.compare-table tbody th[scope="row"] {
  text-align: left;
  white-space: normal;
  font-weight: 500;
  color: var(--color-text-muted);
}

.compare-table td {
  color: var(--color-text);
}

.compare-table tr.compare-group th {
  padding-top: var(--space-5);
  border-bottom: 1px solid var(--color-border-strong);
  text-align: left;
  font-family: var(--font-mono);
  font-size: var(--fs-100);
  text-transform: uppercase;
  letter-spacing: 0.06em;
  color: var(--color-accent-strong);
}

.compare-table tr.compare-group:first-child th {
  padding-top: 0;
}

/* Product comparison table ("How ESUMEI G3 Compares") — subtle ESUMEI
   column highlight, wider min-width for 6 columns, sticky label column */
.compare-table-products {
  min-width: 980px;
}

.compare-table-products th,
.compare-table-products td {
  padding-inline: var(--space-3);
}

.compare-table-products th.col-esumei,
.compare-table-products td.col-esumei {
  background: rgba(242, 128, 63, 0.08);
  box-shadow: inset 2px 0 0 var(--color-accent), inset -2px 0 0 var(--color-accent);
}

.compare-table-products thead th.col-esumei {
  color: var(--color-accent-strong);
}

.compare-table-products tbody td.col-esumei {
  font-weight: 700;
}

/* Sticky characteristic-label column — stays visible while the rest of
   the row scrolls horizontally, so the active scroll area stays legible
   on narrow viewports without a sticky header (which would collide with
   the site's own sticky top nav). */
.compare-table-products th[scope="row"],
.compare-table-products thead th:first-child {
  position: sticky;
  left: 0;
  z-index: 2;
  background: var(--color-bg);
  box-shadow: 1px 0 0 var(--color-border-strong);
}

/* ==========================================================================
   Deployment offer panels
   ========================================================================== */
.offer-grid {
  display: grid;
  gap: var(--space-5);
  margin-top: var(--space-6);
}

.offer-panel {
  position: relative;
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  padding: var(--space-5);
  display: flex;
  flex-direction: column;
  gap: var(--space-3);
}

.offer-panel.is-featured {
  border-color: var(--color-accent);
  box-shadow: var(--shadow-card);
}

.offer-panel .offer-kicker {
  font-family: var(--font-mono);
  font-size: var(--fs-100);
  color: var(--color-signal);
  text-transform: uppercase;
  letter-spacing: 0.08em;
}

.offer-panel h3 {
  margin-bottom: 0;
}

.offer-panel .offer-for {
  color: var(--color-text-muted);
  font-size: var(--fs-200);
}

.offer-panel ul {
  display: grid;
  gap: var(--space-2);
  margin: var(--space-2) 0;
}

.offer-panel li {
  display: flex;
  gap: var(--space-2);
  font-size: var(--fs-200);
  color: var(--color-text);
}

.offer-panel li::before {
  content: "";
  width: 6px;
  height: 6px;
  margin-top: 0.5em;
  border-radius: 50%;
  background: var(--color-accent);
  flex-shrink: 0;
}

.offer-panel .card-actions {
  margin-top: auto;
  padding-top: var(--space-3);
}

/* ==========================================================================
   Platform diagram extras (layer labels + alternate SDK path)
   ========================================================================== */
.layer-tag {
  display: inline-block;
  font-family: var(--font-mono);
  font-size: 0.7rem;
  padding: 0.1em 0.5em;
  border: 1px solid var(--color-border-strong);
  border-radius: 999px;
  color: var(--color-text-faint);
  text-transform: uppercase;
  letter-spacing: 0.05em;
  margin-bottom: var(--space-1);
}

.flow-branch {
  margin-top: var(--space-6);
  padding-top: var(--space-6);
  border-top: 1px dashed var(--color-border);
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: var(--space-4);
}

.flow-branch-label {
  font-family: var(--font-mono);
  font-size: var(--fs-100);
  color: var(--color-text-faint);
  text-transform: uppercase;
  letter-spacing: 0.06em;
}

.flow-branch-path {
  display: flex;
  align-items: center;
  gap: var(--space-3);
  flex-wrap: wrap;
  font-size: var(--fs-200);
  color: var(--color-text-muted);
}

.flow-branch-path strong {
  color: var(--color-text);
}

.flow-branch-arrow {
  color: var(--color-signal);
  font-family: var(--font-mono);
}

/* ==========================================================================
   ESUMEI OS — poll/normalize/buffer/connect/forward strip
   ========================================================================== */
.os-strip {
  display: flex;
  flex-direction: column;
  gap: var(--space-3);
  margin: var(--space-7) 0;
}

.os-step {
  display: flex;
  align-items: center;
  gap: var(--space-4);
  padding: var(--space-4);
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
}

.os-step .os-step-num {
  font-family: var(--font-mono);
  font-size: var(--fs-500);
  font-weight: 700;
  color: var(--color-signal);
  width: 2.2ch;
  flex-shrink: 0;
}

.os-step h3 {
  font-size: var(--fs-400);
  margin-bottom: 0.2em;
}

.os-step p {
  color: var(--color-text-muted);
  margin-bottom: 0;
  font-size: var(--fs-200);
}

.os-step-arrow {
  align-self: center;
  color: var(--color-text-faint);
  font-family: var(--font-mono);
  transform: rotate(90deg);
}

/* ==========================================================================
   ESUMEI Cloud diagram
   ========================================================================== */
.cloud-diagram {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: var(--space-3);
  margin: var(--space-7) 0;
  padding: var(--space-6);
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
}

.cloud-controllers {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: var(--space-3);
}

.cloud-controller-node {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 40px;
  height: 40px;
  border-radius: var(--radius-sm);
  border: 1px solid var(--color-border-strong);
  color: var(--color-text-muted);
}

.cloud-controller-node svg {
  width: 18px;
  height: 18px;
}

.cloud-link {
  width: 2px;
  height: 28px;
  background: repeating-linear-gradient(180deg, var(--color-border-strong) 0 4px, transparent 4px 8px);
}

.cloud-core {
  display: flex;
  align-items: center;
  gap: var(--space-2);
  padding: var(--space-3) var(--space-5);
  border: 1px solid var(--color-signal);
  border-radius: 999px;
  color: var(--color-signal-strong);
  font-family: var(--font-mono);
  font-size: var(--fs-200);
  font-weight: 700;
}

.cloud-core svg {
  width: 20px;
  height: 20px;
}

.cloud-pillars {
  display: grid;
  gap: var(--space-4);
  margin-top: var(--space-6);
}

.cloud-pillar {
  padding: var(--space-4);
  border-left: 2px solid var(--color-accent);
  background: var(--color-surface);
  border-radius: 0 var(--radius-md) var(--radius-md) 0;
}

.cloud-pillar .pillar-kicker {
  font-family: var(--font-mono);
  font-size: var(--fs-100);
  color: var(--color-accent-strong);
  text-transform: uppercase;
  letter-spacing: 0.1em;
}

.cloud-pillar h3 {
  font-size: var(--fs-400);
  margin: 0.2em 0;
}

.cloud-pillar p {
  color: var(--color-text-muted);
  margin-bottom: 0;
  font-size: var(--fs-200);
}

/* ==========================================================================
   Feeder bundle cards
   ========================================================================== */
.bundle-card .bundle-meta {
  display: grid;
  gap: var(--space-2);
  margin: var(--space-2) 0 var(--space-3);
  font-family: var(--font-mono);
  font-size: var(--fs-100);
}

.bundle-meta-row {
  display: flex;
  justify-content: space-between;
  gap: var(--space-3);
  padding-block: var(--space-1);
  border-bottom: 1px dashed var(--color-border);
  color: var(--color-text-muted);
}

.bundle-meta-row span:last-child {
  color: var(--color-text);
  text-align: right;
}

/* ==========================================================================
   Forms
   ========================================================================== */
.order-layout {
  display: grid;
  gap: var(--space-6);
}

.order-aside {
  padding: var(--space-5);
}

.order-aside h3 {
  font-size: var(--fs-300);
  font-family: var(--font-mono);
  text-transform: uppercase;
  letter-spacing: 0.06em;
  color: var(--color-signal);
}

.order-aside ul {
  display: grid;
  gap: var(--space-3);
  margin-top: var(--space-4);
}

.order-aside li {
  display: flex;
  gap: var(--space-2);
  color: var(--color-text-muted);
  font-size: var(--fs-200);
}

.order-aside li::before {
  content: "—";
  color: var(--color-accent);
  flex-shrink: 0;
}

.form-grid {
  display: grid;
  gap: var(--space-4);
}

.form-field {
  display: flex;
  flex-direction: column;
  gap: var(--space-2);
}

.form-field label {
  font-weight: 600;
  font-size: var(--fs-200);
}

.form-field .required-mark {
  color: var(--color-accent-strong);
}

.form-field input,
.form-field select,
.form-field textarea {
  background: var(--color-bg-alt);
  border: 1px solid var(--color-border-strong);
  color: var(--color-text);
  padding: var(--space-3);
  border-radius: var(--radius-sm);
  font: inherit;
  width: 100%;
}

.form-field textarea {
  resize: vertical;
  min-height: 110px;
}

.form-field input:focus,
.form-field select:focus,
.form-field textarea:focus {
  border-color: var(--color-focus);
}

.form-field[data-invalid="true"] input,
.form-field[data-invalid="true"] select,
.form-field[data-invalid="true"] textarea {
  border-color: var(--color-error);
}

.field-error {
  color: var(--color-error);
  font-size: var(--fs-100);
  display: none;
}

.form-field[data-invalid="true"] .field-error {
  display: block;
}

.form-status {
  margin-top: var(--space-4);
  padding: var(--space-4);
  border-radius: var(--radius-sm);
  border: 1px solid var(--color-border-strong);
  background: var(--color-surface);
  display: none;
}

.form-status.is-visible {
  display: block;
}

.form-status.is-success {
  border-color: var(--color-ok);
}

.form-status.is-error {
  border-color: var(--color-error);
}

.quote-status-line {
  font-family: var(--font-mono);
  font-size: var(--fs-200);
  color: var(--color-text-muted);
  margin-top: var(--space-2);
}

/* ==========================================================================
   Contact / distributor block
   ========================================================================== */
.contact-cta {
  text-align: center;
  max-width: 720px;
  margin-inline: auto;
}

.contact-cta h2 {
  font-size: clamp(2.25rem, 6vw, var(--fs-800));
}

.distributor-card {
  background: var(--color-surface);
  padding: var(--space-5);
}

.distributor-card h3 {
  color: var(--color-accent-strong);
  font-family: var(--font-mono);
  font-size: var(--fs-200);
  text-transform: uppercase;
  letter-spacing: 0.06em;
  margin-bottom: var(--space-4);
}

.contact-line {
  display: flex;
  align-items: center;
  gap: var(--space-2);
  margin-bottom: var(--space-3);
}

.contact-line img {
  width: 18px;
  height: 18px;
  flex-shrink: 0;
}

.contact-line a {
  color: var(--color-text);
  text-decoration: none;
  font-family: var(--font-mono);
}

.contact-line a:hover {
  color: var(--color-accent-strong);
}

/* ==========================================================================
   Downloads
   ========================================================================== */
.download-card .download-tag {
  display: inline-block;
  margin-bottom: var(--space-2);
  font-family: var(--font-mono);
  font-size: var(--fs-100);
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.06em;
}

.download-tag.tag-public { color: var(--color-ok); }
.download-tag.tag-restricted { color: var(--color-text-faint); }

/* ==========================================================================
   Footer
   ========================================================================== */
.site-footer {
  padding-block: var(--space-6);
  background: var(--color-bg-alt);
}

.site-footer .footer-top {
  display: flex;
  flex-wrap: wrap;
  justify-content: space-between;
  gap: var(--space-5);
  margin-bottom: var(--space-5);
}

.footer-nav ul {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-4);
}

.footer-nav a {
  color: var(--color-text-muted);
  text-decoration: none;
  font-size: var(--fs-200);
}

.footer-nav a:hover {
  color: var(--color-accent-strong);
}

.footer-distributor {
  font-size: var(--fs-200);
  color: var(--color-text-muted);
}

.footer-distributor a {
  font-family: var(--font-mono);
}

.footer-copyright {
  padding-top: var(--space-4);
  border-top: 1px solid var(--color-border);
  font-family: var(--font-mono);
  font-size: var(--fs-100);
  color: var(--color-text-faint);
}

/* ==========================================================================
   404
   ========================================================================== */
.error-page {
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  text-align: center;
  gap: var(--space-4);
  padding: var(--space-6);
}

/* ==========================================================================
   Responsive
   ========================================================================== */
@media (min-width: 768px) {
  .grid-2 { grid-template-columns: repeat(2, 1fr); }
  .grid-3 { grid-template-columns: repeat(3, 1fr); }

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

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

  .cloud-pillars {
    grid-template-columns: repeat(3, 1fr);
  }

  .flow {
    flex-direction: row;
    align-items: stretch;
  }

  .flow-node {
    flex-direction: column;
    flex: 1;
    padding-inline: var(--space-3);
  }

  .flow-node-marker {
    margin-bottom: var(--space-3);
  }

  .flow-node:not(:last-child)::before {
    left: 52px;
    top: 25px;
    bottom: auto;
    right: -8px;
    width: auto;
    height: 2px;
    background: repeating-linear-gradient(
      90deg,
      var(--color-border-strong) 0,
      var(--color-border-strong) 6px,
      transparent 6px,
      transparent 12px
    );
  }

  @media (prefers-reduced-motion: no-preference) {
    .flow-node:not(:last-child)::after {
      left: 52px;
      top: 24px;
      bottom: auto;
      right: -8px;
      width: auto;
      height: 4px;
      background: linear-gradient(90deg, transparent, var(--color-signal) 45%, transparent);
      background-size: 200% 100%;
      animation: flow-signal-h 3.2s linear infinite;
    }
  }

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

  .order-layout {
    grid-template-columns: 0.8fr 1.2fr;
  }

  .form-grid.two-col {
    grid-template-columns: repeat(2, 1fr);
  }

  .form-field.full-width {
    grid-column: 1 / -1;
  }

}

@keyframes flow-signal-h {
  0% { background-position: -140% 0; }
  100% { background-position: 140% 0; }
}

@media (min-width: 1024px) {
  .container {
    padding-inline: var(--space-6);
  }

  .hero .container {
    grid-template-columns: 1.05fr 0.95fr;
  }

  .nav-toggle {
    display: none;
  }

  .primary-nav {
    position: static;
    inset: auto;
    background: none;
    padding: 0;
    overflow: visible;
    opacity: 1;
    transform: none;
    pointer-events: auto;
  }

  .primary-nav ul {
    counter-reset: none;
    flex-direction: row;
    align-items: center;
    gap: var(--space-1);
  }

  .primary-nav > ul > li > a::before,
  .primary-nav > ul > li summary::before {
    display: none;
  }

  .primary-nav a {
    padding: var(--space-2) var(--space-3);
    border-bottom: none;
    font-size: var(--fs-200);
    font-weight: 600;
    white-space: nowrap;
  }

  .nav-cta {
    display: inline-flex;
    margin-left: var(--space-3);
    margin-top: 0;
  }

  .nav-item-dropdown {
    position: relative;
  }

  .nav-dropdown {
    border-bottom: none;
  }

  .nav-dropdown summary {
    padding: var(--space-2) var(--space-3);
    font-size: var(--fs-200);
    font-weight: 600;
  }

  .nav-dropdown-menu {
    position: absolute;
    top: 100%;
    left: 0;
    margin-top: var(--space-2);
    min-width: 220px;
    padding: var(--space-2);
    background: var(--color-surface-raised);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-sm);
    box-shadow: var(--shadow-card);
  }

  .nav-dropdown:not([open]) .nav-dropdown-menu {
    display: none;
  }

  .nav-dropdown-menu a {
    padding: var(--space-2) var(--space-3);
    border-radius: var(--radius-sm);
    font-size: var(--fs-200);
    white-space: nowrap;
  }

  .nav-dropdown-menu a:hover {
    background: var(--color-surface);
  }

  .os-strip {
    flex-direction: row;
  }

  .os-step {
    flex: 1;
    flex-direction: column;
    text-align: center;
    align-items: center;
    gap: var(--space-2);
  }

  .os-step-arrow {
    align-self: center;
    transform: rotate(0deg);
  }
}