/* ============================================================
   MEMBLIT · Landing Page Stylesheet
   Retro-brutalist. Mono-first. High contrast. No decoration.
   ============================================================ */

/* ------- TOKENS ------- */
:root {
  /* Light mode (default per brief) */
  --bg:        #FFFFFF;
  --fg:        #0A0A0A;
  --fg-soft:   #3A3A3A;
  --line:      #0A0A0A;
  --muted:     #6B6B6B;
  --surface:   #FAFAFA;
  --invert-bg: #0A0A0A;
  --invert-fg: #FFFFFF;

  /* Semantic accents (used as UI language, not decoration) */
  --green:      #2ECC40;   /* correct / verified / proven */
  --green-ink:  #0A0A0A;
  --pink:       #FF3D8A;   /* gap / unproven / needs work */
  --pink-ink:   #0A0A0A;

  /* Type */
  --mono: "JetBrains Mono", ui-monospace, "SF Mono", Menlo, Consolas, monospace;
  --sans: "Inter", -apple-system, BlinkMacSystemFont, "Segoe UI", system-ui, sans-serif;

  /* Scale */
  --step-000: 0.75rem;   /* 12 */
  --step-00:  0.8125rem; /* 13 */
  --step-0:   0.9375rem; /* 15 */
  --step-1:   1rem;      /* 16 */
  --step-2:   1.125rem;  /* 18 */
  --step-3:   1.375rem;  /* 22 */
  --step-4:   1.75rem;   /* 28 */
  --step-5:   2.25rem;   /* 36 */
  --step-6:   3rem;      /* 48 */
  --step-7:   clamp(2.75rem, 7vw + 1rem, 6rem);
  --step-8:   clamp(3.25rem, 9vw + 1rem, 7.5rem);

  /* Space */
  --space-1: 0.5rem;
  --space-2: 1rem;
  --space-3: 1.5rem;
  --space-4: 2rem;
  --space-5: 3rem;
  --space-6: 4rem;
  --space-7: 6rem;
  --space-8: 8rem;

  /* Structural */
  --border: 1.5px;
  --border-strong: 2px;
  --radius: 0;
  --container: 1180px;

  --ease: cubic-bezier(0.2, 0.7, 0.2, 1);
}

/* Dark mode — full palette inversion via [data-theme] */
html[data-theme="dark"] {
  --bg:      #0A0A0A;
  --fg:      #F5F5F5;
  --fg-soft: #C4C4C4;
  --line:    #F5F5F5;
  --muted:   #8B8B8B;
  --surface: #141414;
  --invert-bg: #141414;
  --invert-fg: #F5F5F5;
  --green: #33FF57;
  --pink:  #FF4D97;
}

/* ------- RESET / BASE ------- */
*, *::before, *::after { box-sizing: border-box; }
html {
  -webkit-text-size-adjust: 100%;
}
body {
  margin: 0;
  background: var(--bg);
  color: var(--fg);
  font-family: var(--sans);
  font-size: var(--step-1);
  line-height: 1.55;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
  transition: background 260ms var(--ease), color 260ms var(--ease);
}
img, svg { display: block; max-width: 100%; }
button { font: inherit; cursor: pointer; background: none; border: 0; color: inherit; }
a { color: inherit; text-decoration: none; }
a:hover { text-decoration: underline; text-underline-offset: 3px; }
::selection { background: var(--fg); color: var(--bg); }

.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;
}

.container {
  max-width: var(--container);
  margin: 0 auto;
  padding: 0 clamp(1.25rem, 4vw, 2.5rem);
  position: relative;
  width: 100%;
}
.container--center { text-align: center; }

/* Base Section Styling */
section {
  display: flex;
  flex-direction: column;
  justify-content: center;
  min-height: 100dvh;
}

/* Utility */
.rule {
  border: 0;
  border-top: var(--border) solid var(--line);
  margin: var(--space-4) 0;
  width: 100%;
}
.section-label {
  font-family: var(--mono);
  font-size: var(--step-000);
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--muted);
  margin: 0 0 var(--space-3);
}
.section-label--invert { color: rgba(255,255,255,0.55); }
.section-title {
  font-family: var(--mono);
  font-weight: 800;
  font-size: clamp(2rem, 4.6vw, 3.25rem);
  line-height: 1.02;
  letter-spacing: -0.02em;
  margin: 0 0 var(--space-5);
  text-transform: uppercase;
}

/* Reusable colour marks */
.hl-pink {
  color: var(--pink);
  border-bottom: 2px solid var(--pink);
  padding-bottom: 2px;
  font-weight: 600;
}
.dot {
  display: inline-block;
  width: 8px; height: 8px;
  margin-right: 6px;
  vertical-align: middle;
}
.dot--green { background: var(--green); box-shadow: 0 0 0 2px var(--bg), 0 0 12px var(--green); animation: pulse 2.4s var(--ease) infinite; }
@keyframes pulse {
  0%, 100% { opacity: 1; }
  50% { opacity: 0.4; }
}

/* ============================================================
   SECTION A · NAV
   ============================================================ */
.nav {
  position: sticky;
  top: 0;
  z-index: 50;
  background: var(--bg);
  border-bottom: var(--border) solid var(--line);
  backdrop-filter: blur(8px);
}
.nav__inner {
  max-width: var(--container);
  margin: 0 auto;
  padding: 0.9rem clamp(1.25rem, 4vw, 2.5rem);
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
}
.nav__brand {
  display: inline-flex;
  align-items: center;
  gap: 0.65rem;
  font-family: var(--mono);
  font-weight: 800;
  letter-spacing: 0.16em;
  font-size: var(--step-0);
}
.nav__brand:hover { text-decoration: none; }
.nav__logo { width: 22px; height: 22px; color: var(--fg); }

.theme-toggle {
  display: inline-flex;
  align-items: center;
  gap: 0.55rem;
  font-family: var(--mono);
  font-size: var(--step-000);
  letter-spacing: 0.14em;
  text-transform: uppercase;
  padding: 0.5rem 0.75rem;
  border: var(--border) solid var(--line);
  transition: background 200ms var(--ease);
}
.theme-toggle:hover { background: var(--fg); color: var(--bg); }
.theme-toggle:hover .theme-toggle__switch { border-color: var(--bg); }
.theme-toggle:hover .theme-toggle__dot { background: var(--bg); }
.theme-toggle__label { opacity: 0.4; transition: opacity 200ms var(--ease); }
html[data-theme="light"] .theme-toggle__label[data-mode="light"],
html[data-theme="dark"] .theme-toggle__label[data-mode="dark"] { opacity: 1; }
.theme-toggle__switch {
  position: relative;
  width: 30px; height: 14px;
  border: var(--border) solid var(--line);
  display: inline-block;
}
.theme-toggle__dot {
  position: absolute;
  top: 1px; left: 1px;
  width: 8px; height: 8px;
  background: var(--fg);
  transition: transform 200ms var(--ease);
}
html[data-theme="dark"] .theme-toggle__dot { transform: translateX(16px); }

/* ============================================================
   SECTION B · HERO
   ============================================================ */
.hero {
  padding: clamp(3rem, 8vw, 6rem) 0 clamp(3rem, 8vw, 5rem);
  border-bottom: var(--border) solid var(--line);
  position: relative;
  overflow: hidden;
}
.hero::before {
  content: "";
  position: absolute;
  inset: 0;
  background-image:
    linear-gradient(to right, var(--line) 1px, transparent 1px),
    linear-gradient(to bottom, var(--line) 1px, transparent 1px);
  background-size: 80px 80px;
  opacity: 0.04;
  pointer-events: none;
}
.hero__eyebrow {
  font-family: var(--mono);
  font-size: var(--step-000);
  letter-spacing: 0.18em;
  color: var(--muted);
  margin: 0 0 var(--space-4);
  text-transform: uppercase;
}
.hero__title {
  font-family: var(--mono);
  font-weight: 800;
  font-size: var(--step-8);
  line-height: 0.96;
  letter-spacing: -0.03em;
  margin: 0;
  text-transform: uppercase;
}
.hero__title-accent { display: inline-block; position: relative; }
.cursor {
  display: inline-block;
  width: 0.55ch;
  height: 0.85em;
  background: currentColor;
  vertical-align: -0.08em;
  margin-left: 0.15ch;
  animation: blink 1.05s steps(2, start) infinite;
}
@keyframes blink { to { visibility: hidden; } }

.hero__sub {
  font-size: var(--step-2);
  line-height: 1.55;
  max-width: 62ch;
  color: var(--fg-soft);
  margin: 0 0 var(--space-3);
}
.hero__sub em { font-style: italic; color: var(--fg); font-weight: 500; }

.hero__counter {
  margin-top: var(--space-4);
  font-family: var(--mono);
  font-size: var(--step-000);
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--muted);
}

/* ------- Email capture ------- */
.capture {
  margin-top: var(--space-5);
  max-width: 640px;
}
.capture--center { margin-left: auto; margin-right: auto; }
.capture__row {
  display: flex;
  align-items: stretch;
  border: var(--border-strong) solid var(--line);
  background: var(--bg);
  transition: box-shadow 200ms var(--ease);
}
.capture__row:focus-within { box-shadow: 6px 6px 0 var(--line); transform: translate(-1px, -1px); }
.capture__bracket {
  display: flex;
  align-items: center;
  padding: 0 0.6rem;
  font-family: var(--mono);
  font-weight: 700;
  color: var(--muted);
  background: var(--surface);
  border-right: var(--border) solid var(--line);
}
.capture__row .capture__bracket:last-of-type {
  border-right: var(--border) solid var(--line);
  border-left: 0;
}
.capture__row--secondary {
  border-top: 0;
  width: 100%;
}
.capture__input {
  flex: 2;
  border: 0;
  outline: 0;
  padding: 1rem 0.9rem;
  background: transparent;
  color: var(--fg);
  font-family: var(--mono);
  font-size: var(--step-1);
  min-width: 0;
}
.capture__input--code {
  flex: 1;
  color: var(--green);
  border-left: 0;
  margin-left: 0;
  padding-left: 1rem;
}
.capture__input::placeholder { color: var(--muted); }
.btn {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  padding: 1rem 1.25rem;
  font-family: var(--mono);
  font-weight: 700;
  font-size: var(--step-00);
  letter-spacing: 0.14em;
  text-transform: uppercase;
  border: 0;
  transition: background 180ms var(--ease), color 180ms var(--ease), transform 180ms var(--ease);
  white-space: nowrap;
}
.btn--primary {
  background: var(--fg);
  color: var(--bg);
}
.btn--primary:hover { background: var(--green); color: var(--green-ink); }
.btn--primary:hover .btn__arrow { transform: translateX(3px); }
.btn__arrow { transition: transform 180ms var(--ease); }

.capture__note {
  margin: 0.75rem 0 0;
  font-family: var(--mono);
  font-size: var(--step-000);
  letter-spacing: 0.1em;
  text-transform: uppercase;
  min-height: 1em;
}
.capture__note[data-state="success"] { color: var(--green); }
.capture__note[data-state="error"] { color: var(--pink); }

/* ============================================================
   SECTION B.5 · INTERACTIVE DEMO
   ============================================================ */
.demo-section {
  padding: clamp(3rem, 8vw, 6rem) 0;
  border-bottom: var(--border) solid var(--line);
  background: var(--surface);
}

.demo-app {
  border: var(--border-strong) solid var(--line);
  background: var(--bg);
  box-shadow: 12px 12px 0 var(--line);
  margin-top: var(--space-4);
  max-width: 800px;
  overflow: hidden;
  transition: box-shadow 200ms var(--ease);
}
.demo-app:hover { box-shadow: 16px 16px 0 var(--line); transform: translate(-2px, -2px); }

.demo-app__header {
  border-bottom: var(--border) solid var(--line);
  padding: 0.75rem 1rem;
  display: flex;
  align-items: center;
  background: var(--surface);
}

.demo-app__controls {
  display: flex;
  gap: 6px;
}
.demo-app__controls span {
  width: 12px; height: 12px;
  border: var(--border) solid var(--line);
  border-radius: 50%;
  background: var(--bg);
}
.demo-app__controls span:nth-child(1) { background: var(--pink); }
.demo-app__controls span:nth-child(3) { background: var(--green); }

.demo-app__title {
  margin-left: auto;
  font-family: var(--mono);
  font-size: var(--step-000);
  letter-spacing: 0.16em;
  color: var(--muted);
}

.demo-app__body {
  position: relative;
  min-height: 400px;
  padding: var(--space-4);
}

/* State Management */
.demo-state {
  display: none;
  animation: fadeIn 300ms var(--ease);
}
.demo-state.is-active {
  display: block;
}
@keyframes fadeIn {
  from { opacity: 0; transform: translateY(10px); }
  to { opacity: 1; transform: translateY(0); }
}

/* Dashboard State */
.demo-dash h3 {
  font-family: var(--mono);
  font-weight: 800;
  font-size: var(--step-2);
  margin: 0 0 var(--space-3);
  text-transform: uppercase;
  border-bottom: var(--border) dashed var(--line);
  padding-bottom: var(--space-2);
}

.demo-topic {
  display: grid;
  grid-template-columns: 1fr 1fr auto;
  align-items: center;
  gap: var(--space-3);
  padding: var(--space-3);
  border: var(--border) solid var(--line);
  margin-bottom: var(--space-2);
  transition: transform 150ms var(--ease);
}
.demo-topic:not(.demo-topic--muted):hover {
  transform: translateX(4px);
  border-color: var(--fg);
}
.demo-topic--muted {
  opacity: 0.5;
  background: var(--surface);
}

.demo-topic__info { display: flex; flex-direction: column; gap: 4px; }
.demo-topic__name { font-weight: 600; font-size: var(--step-1); }
.demo-topic__status {
  font-family: var(--mono);
  font-size: var(--step-000);
  color: var(--pink);
  text-transform: uppercase;
  letter-spacing: 0.05em;
}
.demo-topic--muted .demo-topic__status { color: var(--green); }

.demo-topic__calib .calib-row { grid-template-columns: 1fr; padding: 0; }
.demo-topic__calib .calib-label { display: none; }
.demo-topic__calib .calib-bar { height: 8px; }

/* Study State */
.demo-prompt {
  margin-bottom: var(--space-4);
  padding-bottom: var(--space-3);
  border-bottom: var(--border) solid var(--line);
}
.demo-prompt__label {
  display: block;
  font-family: var(--mono);
  font-size: var(--step-000);
  letter-spacing: 0.1em;
  color: var(--muted);
  margin-bottom: var(--space-1);
}
.demo-prompt p {
  font-size: var(--step-2);
  font-weight: 600;
  margin: 0;
}

.demo-produce { margin-bottom: var(--space-4); }
.demo-textarea {
  width: 100%;
  min-height: 120px;
  padding: 1rem;
  font-family: var(--sans);
  font-size: var(--step-1);
  border: var(--border-strong) solid var(--line);
  background: var(--surface);
  color: var(--fg);
  resize: vertical;
  outline: none;
}
.demo-textarea:focus { border-color: var(--pink); }

.btn--text {
  font-family: var(--mono);
  font-size: var(--step-000);
  color: var(--fg-soft);
  text-decoration: underline;
  text-underline-offset: 3px;
  padding: 0; margin-left: 0.5rem;
}
.btn--text:hover { color: var(--fg); }

.demo-guess { margin-bottom: var(--space-4); }
.demo-slider-wrap {
  display: flex;
  align-items: center;
  gap: var(--space-2);
}
.demo-slider {
  flex: 1;
  -webkit-appearance: none;
  width: 100%;
  height: 8px;
  background: var(--surface);
  border: var(--border) solid var(--line);
  outline: none;
}
.demo-slider::-webkit-slider-thumb {
  -webkit-appearance: none;
  appearance: none;
  width: 24px;
  height: 24px;
  background: var(--fg);
  border: var(--border) solid var(--bg);
  cursor: pointer;
  border-radius: 0;
}
.demo-slider::-moz-range-thumb {
  width: 24px;
  height: 24px;
  background: var(--fg);
  border: var(--border) solid var(--bg);
  cursor: pointer;
  border-radius: 0;
}
.demo-slider-val {
  font-family: var(--mono);
  font-weight: 800;
  font-size: var(--step-2);
  min-width: 3ch;
  text-align: right;
}

/* Grading State */
.demo-grading {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  height: 300px;
  gap: var(--space-3);
  font-family: var(--mono);
  font-weight: 700;
  color: var(--muted);
  letter-spacing: 0.1em;
}
.demo-spinner {
  width: 40px; height: 40px;
  border: 4px solid var(--surface);
  border-top-color: var(--pink);
  animation: spin 1s linear infinite;
}
@keyframes spin { 100% { transform: rotate(360deg); } }

/* Result State */
.demo-result h3 {
  font-family: var(--mono);
  font-weight: 800;
  font-size: var(--step-2);
  margin: 0 0 var(--space-4);
  text-transform: uppercase;
  text-align: center;
}
.demo-result__calib {
  display: flex;
  justify-content: center;
  margin-bottom: var(--space-4);
}
.demo-result__calib .calib-demo { margin: 0; width: 100%; }

.demo-result__feedback {
  background: var(--surface);
  border: var(--border) solid var(--line);
  padding: var(--space-3);
  margin-bottom: var(--space-4);
}
.demo-result__feedback p:last-child { margin: 0; }

.demo-actions {
  display: flex;
  justify-content: flex-end;
}

/* ============================================================

   SECTION C · THE PROBLEM (invert block)
   ============================================================ */
.problem {
  background: var(--invert-bg);
  color: var(--invert-fg);
  padding: clamp(4rem, 10vw, 7rem) 0;
  border-bottom: var(--border) solid var(--invert-bg);
}
.problem .section-label { color: rgba(255,255,255,0.5); }
.problem .section-title { color: var(--invert-fg); }
.problem__grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: var(--space-3);
  max-width: 900px;
}
.problem__lead {
  font-family: var(--mono);
  font-size: clamp(1.15rem, 2.1vw, 1.5rem);
  line-height: 1.4;
  letter-spacing: -0.01em;
  margin: 0;
}
.problem__foot {
  margin: var(--space-4) 0 0;
  padding-top: var(--space-2);
  border-top: 1px solid rgba(255,255,255,0.15);
  font-size: var(--step-00);
  color: var(--muted);
  max-width: 70ch;
}

/* ============================================================
   SECTION D · MECHANISM
   ============================================================ */
.mechanism {
  padding: clamp(4rem, 10vw, 7rem) 0;
  border-bottom: var(--border) solid var(--line);
}
.steps {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: var(--space-5);
}
.step {
  display: flex;
  flex-direction: column;
  gap: var(--space-4);
  padding: var(--space-4) 0;
  border-top: var(--border) solid var(--line);
}
.step:last-child { border-bottom: var(--border) solid var(--line); }
.step__marker {
  display: flex;
  flex-direction: column;
  gap: 1rem;
}
.step__num {
  font-family: var(--mono);
  font-weight: 800;
  font-size: clamp(2.75rem, 5vw, 4rem);
  line-height: 1;
  letter-spacing: -0.03em;
}
.step__flow {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  flex-wrap: wrap;
}
.chip {
  display: inline-block;
  font-family: var(--mono);
  font-size: var(--step-000);
  letter-spacing: 0.12em;
  padding: 0.35rem 0.55rem;
  border: var(--border) solid var(--line);
}
.chip--pink { background: var(--pink); color: var(--pink-ink); border-color: var(--pink-ink); }
.chip--green { background: var(--green); color: var(--green-ink); border-color: var(--green-ink); }
.step__arrow { font-family: var(--mono); color: var(--muted); }

.step__title {
  font-family: var(--mono);
  font-weight: 800;
  font-size: clamp(1.15rem, 2vw, 1.5rem);
  letter-spacing: -0.01em;
  margin: 0 0 var(--space-2);
  text-transform: uppercase;
}
.step__body p {
  font-size: var(--step-2);
  color: var(--fg-soft);
  max-width: 62ch;
  margin: 0;
}
.step__body strong { color: var(--fg); }

/* Calibration demo */
.calib-demo {
  margin-top: var(--space-4);
  border: var(--border) solid var(--line);
  padding: 1rem 1.15rem;
  font-family: var(--mono);
  max-width: 480px;
  background: var(--surface);
}
.calib-row {
  display: grid;
  grid-template-columns: 110px 1fr 40px;
  align-items: center;
  gap: 0.75rem;
  padding: 0.35rem 0;
  font-size: var(--step-000);
  letter-spacing: 0.1em;
  text-transform: uppercase;
}
.calib-row--delta {
  grid-template-columns: 110px 1fr;
  border-top: var(--border) dashed var(--line);
  margin-top: 0.4rem;
  padding-top: 0.65rem;
}
.calib-label { color: var(--muted); }
.calib-bar {
  height: 10px;
  background: transparent;
  border: var(--border) solid var(--line);
  position: relative;
}
.calib-fill { height: 100%; }
.calib-fill--pink  { background: var(--pink);  animation: fillIn 900ms var(--ease) both; }
.calib-fill--green { background: var(--green); animation: fillIn 900ms var(--ease) 200ms both; }
@keyframes fillIn { from { transform: scaleX(0); transform-origin: left; } to { transform: scaleX(1); } }
.calib-val { text-align: right; font-weight: 700; }
.calib-delta { color: var(--pink); font-weight: 700; letter-spacing: 0.1em; }

/* ============================================================
   SECTION E · THE ANTI-FEATURE
   ============================================================ */
.anti {
  padding: clamp(3rem, 8vw, 5rem) 0;
  border-bottom: var(--border) solid var(--line);
}
.anti__box {
  display: grid;
  grid-template-columns: 6px 1fr;
  border: var(--border-strong) solid var(--line);
  background: var(--surface);
}
.anti__bar { background: var(--pink); }
.anti__content { padding: clamp(1.5rem, 4vw, 2.5rem); }
.anti__tag {
  font-family: var(--mono);
  font-size: var(--step-000);
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--pink);
  margin: 0 0 var(--space-2);
}
.anti__title {
  font-family: var(--mono);
  font-weight: 800;
  font-size: clamp(1.5rem, 3vw, 2.15rem);
  letter-spacing: -0.02em;
  text-transform: uppercase;
  margin: 0 0 var(--space-3);
}
.anti p { font-size: var(--step-1); color: var(--fg-soft); max-width: 65ch; margin: 0 0 var(--space-3); }
.anti em { font-style: italic; color: var(--fg); font-weight: 500; }
.anti__list {
  list-style: none;
  padding: 0;
  margin: var(--space-3) 0;
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem 1.5rem;
  font-family: var(--mono);
  font-size: var(--step-00);
  letter-spacing: 0.06em;
}
.anti__list li { display: inline-flex; align-items: center; gap: 0.5rem; }
.x { color: var(--pink); font-weight: 800; }
.anti__foot {
  border-top: var(--border) dashed var(--line);
  padding-top: var(--space-3);
  font-family: var(--mono);
  font-size: var(--step-2);
  color: var(--fg);
  margin: var(--space-3) 0 0;
  max-width: none;
}

/* ============================================================
   SECTION F · WHO WE ARE
   ============================================================ */
.who {
  padding: clamp(4rem, 10vw, 7rem) 0;
  border-bottom: var(--border) solid var(--line);
}
.who__grid {
  display: grid;
  grid-template-columns: 1.2fr 1fr;
  gap: var(--space-6);
  align-items: start;
}
.who__col p {
  font-size: var(--step-2);
  color: var(--fg-soft);
  margin: 0 0 var(--space-3);
  max-width: 55ch;
}
.who__col p strong { color: var(--fg); }
.who__facts {
  list-style: none;
  padding: 0;
  margin: 0;
  border: var(--border) solid var(--line);
  background: var(--surface);
}
.who__facts li {
  display: grid;
  grid-template-columns: 120px 1fr;
  gap: 1rem;
  padding: 0.9rem 1.1rem;
  border-bottom: var(--border) dashed var(--line);
  font-family: var(--mono);
  font-size: var(--step-00);
  align-items: center;
}
.who__facts li:last-child { border-bottom: 0; }
.who__key {
  color: var(--muted);
  letter-spacing: 0.12em;
  text-transform: uppercase;
  font-size: var(--step-000);
}
.who__val { letter-spacing: 0.02em; }
.who__val .dot { margin-right: 4px; }

/* ============================================================
   SECTION G · REFERRAL
   ============================================================ */
.referral {
  background: var(--invert-bg);
  color: var(--invert-fg);
  padding: clamp(4rem, 10vw, 6rem) 0;
  border-bottom: var(--border) solid var(--invert-bg);
}
.referral__title {
  font-family: var(--mono);
  font-weight: 800;
  font-size: clamp(2rem, 5vw, 3.5rem);
  letter-spacing: -0.02em;
  text-transform: uppercase;
  line-height: 1;
  margin: 0 0 var(--space-4);
  color: var(--invert-fg);
}
.pos, .pos-1 {
  display: inline-block;
  padding: 0 0.3ch;
  color: var(--green);
}
.referral__body {
  font-size: var(--step-2);
  color: rgba(255,255,255,0.8);
  max-width: 62ch;
  margin: 0 0 var(--space-5);
}
.referral__body strong { color: var(--invert-fg); }

.referral__cmd {
  display: flex;
  align-items: center;
  gap: 0.8rem;
  flex-wrap: wrap;
  border: var(--border-strong) solid rgba(255,255,255,0.85);
  padding: 0.9rem 1.15rem;
  font-family: var(--mono);
  font-size: var(--step-00);
  letter-spacing: 0.06em;
  margin-bottom: var(--space-5);
  transition: background 180ms var(--ease), color 180ms var(--ease);
  outline: none;
  max-width: 680px;
}
.referral__cmd:hover, .referral__cmd:focus-visible {
  background: var(--green);
  color: var(--green-ink);
  border-color: var(--green);
}
.referral__cmd:hover .referral__result,
.referral__cmd:hover .referral__prompt { color: var(--green-ink); }
.referral__prompt { color: var(--green); font-weight: 800; }
.referral__result { color: rgba(255,255,255,0.6); }
.referral__hint {
  margin-left: auto;
  font-size: var(--step-000);
  letter-spacing: 0.16em;
  color: rgba(255,255,255,0.5);
  text-transform: uppercase;
}
.referral__cmd:hover .referral__hint { color: var(--green-ink); }

.progress { max-width: 680px; }
.progress__bar {
  display: grid;
  grid-template-columns: repeat(10, 1fr);
  gap: 6px;
  margin-bottom: 0.75rem;
}
.progress__block {
  height: 22px;
  border: var(--border) solid rgba(255,255,255,0.4);
  background: transparent;
  transform: skewX(-12deg);
  transition: background 300ms var(--ease), border-color 300ms var(--ease);
}
.progress__block--on {
  background: var(--green);
  border-color: var(--green);
}
.progress__label {
  font-family: var(--mono);
  font-size: var(--step-000);
  letter-spacing: 0.16em;
  color: rgba(255,255,255,0.65);
  margin: 0;
}

/* ============================================================
   SECTION H · FAQ
   ============================================================ */
.faq {
  padding: clamp(4rem, 10vw, 7rem) 0;
  border-bottom: var(--border) solid var(--line);
}
.faq__list {
  border-top: var(--border) solid var(--line);
}
.faq__item {
  border-bottom: var(--border) solid var(--line);
}
.faq__item summary {
  list-style: none;
  cursor: pointer;
  padding: 1.35rem 0.25rem;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  transition: padding 200ms var(--ease);
}
.faq__item summary::-webkit-details-marker { display: none; }
.faq__item:hover summary { padding-left: 0.75rem; }
.faq__q {
  font-family: var(--mono);
  font-weight: 700;
  font-size: var(--step-1);
  letter-spacing: 0.02em;
  text-transform: uppercase;
}
.prompt { color: var(--green); margin-right: 0.35em; }
.faq__sign {
  position: relative;
  width: 14px;
  height: 14px;
  flex-shrink: 0;
}
.faq__sign::before, .faq__sign::after {
  content: "";
  position: absolute;
  background: currentColor;
  transition: transform 220ms var(--ease);
}
.faq__sign::before {
  top: 6px; left: 0; width: 14px; height: 2px;
}
.faq__sign::after {
  top: 0; left: 6px; width: 2px; height: 14px;
}
.faq__item[open] .faq__sign::after { transform: rotate(90deg); }
.faq__item p {
  padding: 0 0.25rem 1.5rem;
  margin: -0.35rem 0 0;
  max-width: 70ch;
  color: var(--fg-soft);
  font-size: var(--step-1);
}

/* ============================================================
   SECTION I · FINAL CTA
   ============================================================ */
.final {
  padding: clamp(4rem, 10vw, 7rem) 0;
  border-bottom: var(--border) solid var(--line);
  background: var(--bg);
  background-blend-mode: normal;
  position: relative;
}
.final::before {
  content: "";
  position: absolute; inset: -200px; /* Expand to cover after slant */
  background-image:
    repeating-linear-gradient(12deg, transparent, transparent 39px, var(--line) 39px, var(--line) 40px);
  opacity: 0.04;
  pointer-events: none;
}
.final .container { position: relative; z-index: 1; }
.final__title {
  font-family: var(--mono);
  font-weight: 800;
  font-size: clamp(2rem, 5.5vw, 4rem);
  line-height: 1;
  letter-spacing: -0.03em;
  text-transform: uppercase;
  margin: 0 auto var(--space-5);
  max-width: 20ch;
}
.final__accent {
  background: var(--green);
  color: var(--green-ink);
  padding: 0 0.15em;
  display: inline-block;
}

/* ============================================================
   SECTION J · FOOTER
   ============================================================ */
.foot {
  padding: var(--space-4) 0;
  border-top: var(--border) solid var(--line);
}
.foot__inner {
  display: flex;
  flex-wrap: wrap;
  gap: 0.6rem 1rem;
  align-items: center;
  justify-content: center;
  font-family: var(--mono);
  font-size: var(--step-000);
  letter-spacing: 0.12em;
  color: var(--muted);
  text-transform: uppercase;
}
.foot__sep { color: var(--muted); opacity: 0.5; }
.foot__brand { color: var(--fg); font-weight: 700; }
.foot__link { color: var(--fg); }

/* ============================================================
   Responsive
   ============================================================ */
@media (max-width: 860px) {
  .who__grid { grid-template-columns: 1fr; gap: var(--space-4); }
  .step { grid-template-columns: 1fr; gap: var(--space-3); }
  .step__marker { flex-direction: row; align-items: center; }
  .step__num { font-size: 2.5rem; }
  .referral__title { font-size: clamp(1.5rem, 4vw, 2.5rem); }
  .section-title { font-size: clamp(1.5rem, 4vw, 2.5rem); }
}
@media (max-width: 640px) {
  .container { padding: 0 1rem; }
  .capture__row { flex-direction: column; align-items: stretch; }
  .capture__bracket:first-of-type,
  .capture__row .capture__bracket:last-of-type {
    display: none;
  }
  .capture__input { border-right: 0; border-bottom: var(--border) solid var(--line); }
  .btn--primary { width: 100%; justify-content: center; padding: 1rem; }
  .hero__title { font-size: clamp(2rem, 8vw, 3.5rem); }
  .hero__sub { font-size: var(--step-1); }
  .hero { padding: clamp(3rem, 6vw, 5rem) 0; }
  .problem { padding: clamp(3rem, 6vw, 5rem) 0; }
  .mechanism { padding: clamp(3rem, 6vw, 5rem) 0; }
  .anti { padding: clamp(2rem, 4vw, 3rem) 0; }
  .referral { padding: clamp(3rem, 6vw, 5rem) 0; }
  .faq { padding: clamp(3rem, 6vw, 5rem) 0; }
  .final { padding: clamp(3rem, 6vw, 5rem) 0; }
  .steps { grid-template-columns: 1fr; }
  .step__body p { font-size: var(--step-1); }
  .progress__bar { grid-template-columns: repeat(10, 1fr); gap: 4px; }
  .progress__block { height: 18px; }
  .who__facts li { grid-template-columns: 1fr; gap: 0.25rem; }
  .referral__cmd { flex-direction: column; align-items: flex-start; gap: 0.5rem; }
  .referral__hint { margin-left: 0; }
  .demo-app__body { padding: 1rem; }
  .calib-row { grid-template-columns: 80px 1fr 30px; gap: 0.5rem; font-size: 0.65rem; }
  .calib-row--delta { grid-template-columns: 80px 1fr; }
}
@media (max-width: 420px) {
  .theme-toggle__label { display: none; }
  .theme-toggle__label[data-mode="light"],
  .theme-toggle__label[data-mode="dark"] { display: inline; }
  html[data-theme="light"] .theme-toggle__label[data-mode="dark"],
  html[data-theme="dark"] .theme-toggle__label[data-mode="light"] { display: none; }
  .hero__title { font-size: clamp(1.75rem, 7vw, 2.5rem); }
  .referral__title { font-size: clamp(1.25rem, 5vw, 2rem); line-height: 1.15; }
  .final__title { font-size: clamp(1.5rem, 5vw, 2.5rem); }
}

/* ------- ONTOLOGY SECTION ------- */
.ontology__grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: var(--space-5);
  align-items: center;
}
.ontology__list {
  list-style: none;
  padding: 0;
  margin: var(--space-3) 0;
}
.ontology__list li {
  display: flex;
  align-items: baseline;
  gap: 0.75rem;
  margin-bottom: 0.75rem;
  font-size: var(--step-0);
  line-height: 1.5;
}
.ontology__list li .chip {
  flex-shrink: 0;
}
.ontology__graph {
  border: 1px solid var(--line);
  padding: 1.5rem;
  display: flex;
  align-items: center;
  justify-content: center;
}
.ontology__svg {
  width: 100%;
  max-width: 420px;
  height: auto;
}
@media (max-width: 768px) {
  .ontology__grid {
    grid-template-columns: 1fr;
  }
}

/* Focus states — never hidden */
button:focus-visible, a:focus-visible, summary:focus-visible, input:focus-visible, [tabindex]:focus-visible {
  outline: 2px dashed var(--fg);
  outline-offset: 3px;
}

/* Motion accommodation */
@media (prefers-reduced-motion: reduce) {
  * { animation: none !important; transition: none !important; }
}

/* Buttons (secondary) */
.btn--outline {
  background: transparent;
  color: var(--fg);
  border: var(--border-strong) solid var(--line);
}
.btn--outline:hover {
  background: var(--fg);
  color: var(--bg);
}

/* Chips */
.chip {
  display: inline-flex;
  align-items: center;
  font-family: var(--mono);
  font-size: var(--step-000);
  font-weight: 700;
  letter-spacing: 0.1em;
  padding: 0.2rem 0.6rem;
  border: var(--border) solid var(--line);
  border-radius: 4px;
  background: var(--surface);
  color: var(--fg);
  line-height: 1.2;
}
.chip--green {
  background: var(--green);
  color: var(--green-ink);
}
.chip--pink {
  background: var(--pink);
  color: var(--pink-ink);
}