/* ---------- self-hosted fonts ---------- */
@font-face { font-family: 'Switzer'; src: url('../fonts/switzer-500.woff2') format('woff2'); font-weight: 500; font-style: normal; font-display: swap; }
@font-face { font-family: 'Switzer'; src: url('../fonts/switzer-600.woff2') format('woff2'); font-weight: 600; font-style: normal; font-display: swap; }
@font-face { font-family: 'Switzer'; src: url('../fonts/switzer-700.woff2') format('woff2'); font-weight: 700; font-style: normal; font-display: swap; }
@font-face { font-family: 'Satoshi'; src: url('../fonts/satoshi-400.woff2') format('woff2'); font-weight: 400; font-style: normal; font-display: swap; }
@font-face { font-family: 'Satoshi'; src: url('../fonts/satoshi-500.woff2') format('woff2'); font-weight: 500; font-style: normal; font-display: swap; }
@font-face { font-family: 'Satoshi'; src: url('../fonts/satoshi-700.woff2') format('woff2'); font-weight: 700; font-style: normal; font-display: swap; }
@font-face { font-family: 'JetBrains Mono'; src: url('../fonts/jetbrains-mono.woff2') format('woff2'); font-weight: 400 500; font-style: normal; font-display: swap; }

/* ==========================================================================
   D & W Surface Technologies — design system
   Direction: clean Swiss / lab white. Cool neutral surfaces, precision grid,
   one precision-blue accent (low temperature), heat-orange reserved for data.
   ========================================================================== */

:root,
[data-theme='light'] {
  /* Type scale */
  --text-xs: clamp(0.75rem, 0.7rem + 0.25vw, 0.875rem);
  --text-sm: clamp(0.875rem, 0.8rem + 0.35vw, 1rem);
  --text-base: clamp(1rem, 0.95rem + 0.25vw, 1.125rem);
  --text-lg: clamp(1.125rem, 1rem + 0.75vw, 1.5rem);
  --text-xl: clamp(1.5rem, 1.2rem + 1.25vw, 2.25rem);
  --text-2xl: clamp(2rem, 1.2rem + 2.5vw, 3.5rem);
  --text-3xl: clamp(2.5rem, 1rem + 4vw, 5rem);

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

  /* Surfaces — lab white, cool neutral */
  --color-bg: #fbfbfc;
  --color-surface: #ffffff;
  --color-surface-2: #f6f7f9;
  --color-surface-offset: #f1f3f6;
  --color-surface-offset-2: #e9ecf1;
  --color-surface-dynamic: #e2e6ec;
  --color-divider: #e4e7ec;
  --color-border: #d7dce3;

  /* Text */
  --color-text: #0e1418;
  --color-text-muted: #5c6670;
  --color-text-faint: #a2aab4;
  --color-text-inverse: #fbfbfc;

  /* Primary — precision blue */
  --color-primary: #0f4fd1;
  --color-primary-hover: #0a3ca8;
  --color-primary-active: #082e80;
  --color-primary-highlight: #dce6fa;

  /* Heat — data visualisation only (conventional high-temperature processes) */
  --color-heat: #c2410c;
  --color-heat-highlight: #f7e3d8;
  --color-success: #17683d;

  --radius-sm: 0.25rem;
  --radius-md: 0.375rem;
  --radius-lg: 0.625rem;
  --radius-full: 9999px;

  --transition-interactive: 180ms cubic-bezier(0.16, 1, 0.3, 1);

  --shadow-sm: 0 1px 2px oklch(0.25 0.02 250 / 0.06);
  --shadow-md:
    0 1px 2px oklch(0.25 0.02 250 / 0.05), 0 6px 20px oklch(0.25 0.02 250 / 0.06);
  --shadow-lg:
    0 2px 4px oklch(0.25 0.02 250 / 0.06), 0 16px 40px oklch(0.25 0.02 250 / 0.1);

  --content-narrow: 660px;
  --content-default: 1000px;
  --content-wide: 1240px;

  --font-display: 'Switzer', 'Helvetica Neue', sans-serif;
  --font-body: 'Satoshi', 'Inter', sans-serif;
  --font-mono: 'JetBrains Mono', ui-monospace, monospace;
}

[data-theme='dark'] {
  --color-bg: #0c0f12;
  --color-surface: #11151a;
  --color-surface-2: #161b21;
  --color-surface-offset: #14181d;
  --color-surface-offset-2: #1a1f26;
  --color-surface-dynamic: #232a32;
  --color-divider: #1c2229;
  --color-border: #2a323b;
  --color-text: #d9dee4;
  --color-text-muted: #7d8792;
  --color-text-faint: #565f69;
  --color-text-inverse: #11151a;
  --color-primary: #7ba6f7;
  --color-primary-hover: #9dbdfa;
  --color-primary-active: #b6cefb;
  --color-primary-highlight: #1a2740;
  --color-heat: #f08a52;
  --color-heat-highlight: #33231a;
  --color-success: #59b183;
  --shadow-sm: 0 1px 2px oklch(0 0 0 / 0.4);
  --shadow-md: 0 4px 14px oklch(0 0 0 / 0.45);
  --shadow-lg: 0 16px 40px oklch(0 0 0 / 0.55);
}

@media (prefers-color-scheme: dark) {
  :root:not([data-theme]) {
    --color-bg: #0c0f12;
    --color-surface: #11151a;
    --color-surface-2: #161b21;
    --color-surface-offset: #14181d;
    --color-surface-offset-2: #1a1f26;
    --color-surface-dynamic: #232a32;
    --color-divider: #1c2229;
    --color-border: #2a323b;
    --color-text: #d9dee4;
    --color-text-muted: #7d8792;
    --color-text-faint: #565f69;
    --color-text-inverse: #11151a;
    --color-primary: #7ba6f7;
    --color-primary-hover: #9dbdfa;
    --color-primary-highlight: #1a2740;
    --color-heat: #f08a52;
  }
}

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

html {
  -webkit-text-size-adjust: none;
  text-size-adjust: none;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  text-rendering: optimizeLegibility;
  scroll-behavior: smooth;
  scroll-padding-top: 6rem;
}

body {
  min-height: 100dvh;
  line-height: 1.6;
  font-family: var(--font-body);
  font-size: var(--text-base);
  color: var(--color-text);
  background: var(--color-bg);
}

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

img {
  background: var(--color-surface-offset);
}

h1,
h2,
h3,
h4 {
  text-wrap: balance;
  line-height: 1.12;
  letter-spacing: -0.02em;
  font-family: var(--font-display);
  font-weight: 600;
}

p,
li {
  text-wrap: pretty;
}

a {
  color: var(--color-primary);
  text-decoration-thickness: 1px;
  text-underline-offset: 3px;
}

button {
  cursor: pointer;
  background: none;
  border: none;
}

input,
button,
textarea,
select {
  font: inherit;
  color: inherit;
}

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

::selection {
  background: var(--color-primary-highlight);
  color: var(--color-text);
}

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

a,
button,
input,
textarea,
select,
.card {
  transition:
    color var(--transition-interactive),
    background var(--transition-interactive),
    border-color var(--transition-interactive),
    box-shadow var(--transition-interactive),
    transform var(--transition-interactive);
}

@media (prefers-reduced-motion: reduce) {
  *,
  *::before,
  *::after {
    animation-duration: 0.01ms !important;
    transition-duration: 0.01ms !important;
    scroll-behavior: auto !important;
  }
}

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

/* ---------- layout ---------- */
.container {
  width: 100%;
  max-width: var(--content-wide);
  margin-inline: auto;
  padding-inline: var(--space-5);
}

@media (min-width: 900px) {
  .container {
    padding-inline: var(--space-10);
  }
}

.narrow {
  max-width: var(--content-narrow);
}

.section {
  padding-block: clamp(var(--space-16), 8vw, var(--space-32));
}

.section--tight {
  padding-block: clamp(var(--space-12), 5vw, var(--space-20));
}

.section--offset {
  background: var(--color-surface-2);
  border-block: 1px solid var(--color-divider);
}

.rule {
  border: 0;
  border-top: 1px solid var(--color-divider);
}

/* ---------- type utilities ---------- */
.eyebrow {
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  font-weight: 500;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--color-primary);
  display: flex;
  align-items: center;
  gap: var(--space-3);
  margin-bottom: var(--space-5);
}

.eyebrow::before {
  content: '';
  width: 22px;
  height: 1px;
  background: currentColor;
  flex: none;
}

.h-hero {
  font-size: var(--text-2xl);
  font-weight: 600;
}

.h-section {
  font-size: var(--text-xl);
  max-width: 22ch;
}

.h-sub {
  font-family: var(--font-body);
  font-size: var(--text-lg);
  font-weight: 700;
  letter-spacing: -0.01em;
  line-height: 1.25;
}

.lead {
  font-size: var(--text-lg);
  line-height: 1.5;
  color: var(--color-text-muted);
  max-width: 46ch;
}

.body-muted {
  color: var(--color-text-muted);
  max-width: 62ch;
}

.mono {
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
}

.stack > * + * {
  margin-top: var(--space-4);
}

.mt-8 {
  margin-top: var(--space-8);
}
.mt-10 {
  margin-top: var(--space-10);
}
.mt-12 {
  margin-top: var(--space-12);
}

/* ---------- header ---------- */
.header {
  position: sticky;
  top: 0;
  z-index: 60;
  background: color-mix(in oklab, var(--color-bg) 88%, transparent);
  backdrop-filter: blur(14px) saturate(1.4);
  border-bottom: 1px solid var(--color-divider);
}

.header__inner {
  display: flex;
  align-items: center;
  gap: var(--space-6);
  min-height: 72px;
}

.logo {
  display: flex;
  align-items: center;
  gap: var(--space-3);
  color: var(--color-text);
  text-decoration: none;
  flex: none;
}

.logo:hover {
  color: var(--color-primary);
}

.logo svg {
  flex: none;
  color: currentColor;
}

.logo__text {
  display: flex;
  flex-direction: column;
  line-height: 1;
}

.logo__name {
  font-family: var(--font-display);
  font-size: 1.25rem;
  font-weight: 700;
  letter-spacing: -0.015em;
}

.logo__sub {
  font-family: var(--font-mono);
  font-size: 0.625rem;
  letter-spacing: 0.17em;
  text-transform: uppercase;
  color: var(--color-text-muted);
  margin-top: 4px;
}

.nav {
  display: none;
  margin-left: auto;
  align-items: center;
  gap: var(--space-6);
}

.nav a {
  font-size: var(--text-sm);
  font-weight: 500;
  color: var(--color-text-muted);
  text-decoration: none;
  padding-block: var(--space-2);
}

.nav a:hover {
  color: var(--color-text);
}

.nav a[aria-current='page'] {
  color: var(--color-text);
  box-shadow: inset 0 -2px 0 var(--color-primary);
}

.header__actions .header__cta {
  display: none;
}

@media (min-width: 560px) {
  .header__actions .header__cta {
    display: inline-flex;
  }
}

.header__actions {
  display: flex;
  align-items: center;
  gap: var(--space-2);
  margin-left: auto;
}

@media (min-width: 1000px) {
  .nav {
    display: flex;
  }
  .header__actions {
    margin-left: var(--space-4);
  }
}

.icon-btn {
  display: grid;
  place-items: center;
  width: 40px;
  height: 40px;
  border-radius: var(--radius-md);
  color: var(--color-text-muted);
  border: 1px solid transparent;
}

.icon-btn:hover {
  color: var(--color-text);
  background: var(--color-surface-offset-2);
}

.menu-btn {
  display: grid;
}

@media (min-width: 1000px) {
  .menu-btn {
    display: none;
  }
}

.mobile-nav {
  display: none;
  border-top: 1px solid var(--color-divider);
  background: var(--color-surface);
  padding: var(--space-3) 0 var(--space-5);
}

.mobile-nav[data-open='true'] {
  display: block;
}

.mobile-nav a {
  display: block;
  padding: var(--space-3) 0;
  font-size: var(--text-base);
  font-weight: 500;
  color: var(--color-text);
  text-decoration: none;
  border-bottom: 1px solid var(--color-divider);
}

.mobile-nav a.mobile-nav__cta {
  display: flex;
  margin-top: var(--space-4);
  border-bottom: 0;
  color: #fff;
}

@media (min-width: 560px) {
  .mobile-nav a.mobile-nav__cta {
    display: none;
  }
}

/* ---------- buttons ---------- */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-2);
  min-height: 46px;
  padding: 0 var(--space-5);
  border-radius: var(--radius-md);
  font-size: var(--text-sm);
  font-weight: 600;
  text-decoration: none;
  border: 1px solid transparent;
  white-space: nowrap;
}

.btn--primary {
  background: var(--color-primary);
  color: #fff;
}

[data-theme='dark'] .btn--primary {
  color: #0b1017;
}

.btn--primary:hover {
  background: var(--color-primary-hover);
  transform: translateY(-1px);
  box-shadow: var(--shadow-md);
}

.btn--ghost {
  border-color: var(--color-border);
  color: var(--color-text);
  background: var(--color-surface);
}

.btn--ghost:hover {
  border-color: var(--color-text-muted);
  background: var(--color-surface-offset);
}

.btn--sm {
  min-height: 40px;
  padding: 0 var(--space-4);
}

.btn-row {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-3);
}

.link-arrow {
  display: inline-flex;
  align-items: center;
  gap: var(--space-2);
  font-size: var(--text-sm);
  font-weight: 600;
  text-decoration: none;
}

.link-arrow svg {
  transition: transform var(--transition-interactive);
}

.link-arrow:hover svg {
  transform: translateX(4px);
}

/* ---------- hero ---------- */
.hero {
  border-bottom: 1px solid var(--color-divider);
  position: relative;
  overflow: hidden;
}

.hero__grid {
  display: grid;
  gap: var(--space-10);
  padding-block: clamp(var(--space-12), 7vw, var(--space-24));
  align-items: center;
}

@media (min-width: 950px) {
  .hero__grid {
    grid-template-columns: minmax(0, 0.92fr) minmax(0, 1.08fr);
    gap: var(--space-16);
  }
}

.hero h1 {
  font-size: var(--text-2xl);
}

.hero__figure {
  position: relative;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  overflow: hidden;
  background: var(--color-surface);
}

.hero__figure img {
  width: 100%;
  aspect-ratio: 1 / 1;
  object-fit: cover;
}

[data-theme='dark'] .hero__figure img,
[data-theme='dark'] .fig img {
  filter: brightness(0.94) contrast(1.02);
}

.hero__tag {
  position: absolute;
  left: var(--space-4);
  bottom: var(--space-4);
  background: color-mix(in oklab, var(--color-surface) 90%, transparent);
  backdrop-filter: blur(8px);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-sm);
  padding: var(--space-2) var(--space-3);
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  color: var(--color-text-muted);
}

/* grid backdrop for hero */
.grid-bg::before {
  content: '';
  position: absolute;
  inset: 0;
  pointer-events: none;
  background-image:
    linear-gradient(to right, var(--color-divider) 1px, transparent 1px),
    linear-gradient(to bottom, var(--color-divider) 1px, transparent 1px);
  background-size: 64px 64px;
  mask-image: radial-gradient(120% 90% at 15% 0%, #000 0%, transparent 68%);
  opacity: 0.65;
}

.hero > .container {
  position: relative;
}

/* ---------- spec strip ---------- */
.specs {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  border-top: 1px solid var(--color-divider);
}

@media (min-width: 800px) {
  .specs {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }
}

.spec {
  padding: var(--space-6) var(--space-5);
  border-right: 1px solid var(--color-divider);
  border-bottom: 1px solid var(--color-divider);
}

@media (min-width: 800px) {
  .spec {
    border-bottom: 0;
    padding: var(--space-8) var(--space-6);
  }
  .spec:last-child {
    border-right: 0;
  }
}

.spec__value {
  font-family: var(--font-display);
  font-size: clamp(1.5rem, 1rem + 1.6vw, 2.125rem);
  font-weight: 600;
  letter-spacing: -0.03em;
  font-variant-numeric: tabular-nums;
  line-height: 1;
}

.spec__unit {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  font-weight: 400;
  color: var(--color-text-muted);
  letter-spacing: 0;
  margin-left: 2px;
}

.spec__label {
  margin-top: var(--space-3);
  font-size: var(--text-xs);
  color: var(--color-text-muted);
  max-width: 24ch;
}

/* ---------- two column ---------- */
.two-col {
  display: grid;
  gap: var(--space-10);
  align-items: start;
}

@media (min-width: 950px) {
  .two-col {
    grid-template-columns: minmax(0, 1fr) minmax(0, 1fr);
    gap: clamp(var(--space-12), 6vw, var(--space-20));
  }
  .two-col--sticky > :first-child {
    position: sticky;
    top: 6.5rem;
  }
  .two-col--flip > :first-child {
    order: 2;
  }
}

.fig {
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  overflow: hidden;
  background: var(--color-surface);
}

.fig img {
  width: 100%;
  object-fit: cover;
}

.fig figcaption {
  padding: var(--space-4) var(--space-5);
  border-top: 1px solid var(--color-divider);
  font-size: var(--text-xs);
  color: var(--color-text-muted);
  background: var(--color-surface-2);
}

/* ---------- cards ---------- */
.cards {
  display: grid;
  gap: var(--space-5);
  grid-template-columns: repeat(auto-fill, minmax(min(280px, 100%), 1fr));
}

.card {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  padding: var(--space-6);
}

.card--link:hover {
  border-color: var(--color-primary);
  box-shadow: var(--shadow-md);
  transform: translateY(-2px);
}

.card__num {
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  color: var(--color-primary);
  letter-spacing: 0.1em;
  margin-bottom: var(--space-4);
  display: block;
}

.card h3 {
  font-family: var(--font-body);
  font-size: var(--text-base);
  font-weight: 700;
  letter-spacing: -0.01em;
  margin-bottom: var(--space-2);
}

.card p {
  font-size: var(--text-sm);
  color: var(--color-text-muted);
  line-height: 1.6;
}

.card__icon {
  color: var(--color-primary);
  margin-bottom: var(--space-4);
}

/* checklist */
.check {
  list-style: none;
  display: grid;
  gap: var(--space-3);
}

.check li {
  display: grid;
  grid-template-columns: 20px 1fr;
  gap: var(--space-3);
  font-size: var(--text-sm);
  color: var(--color-text-muted);
  align-items: start;
}

.check svg {
  margin-top: 3px;
  color: var(--color-primary);
}

.check strong {
  color: var(--color-text);
  font-weight: 600;
}

/* ---------- process steps ---------- */
.steps {
  display: grid;
  gap: 0;
  counter-reset: step;
  border-top: 1px solid var(--color-divider);
}

.step {
  display: grid;
  gap: var(--space-2) var(--space-6);
  padding-block: var(--space-6);
  border-bottom: 1px solid var(--color-divider);
}

@media (min-width: 800px) {
  .step {
    grid-template-columns: 5.5rem minmax(0, 15rem) minmax(0, 1fr);
    align-items: baseline;
    padding-block: var(--space-8);
  }
}

@media (min-width: 800px) {
  .steps--stack .step {
    grid-template-columns: 3.5rem minmax(0, 1fr);
    gap: var(--space-3) var(--space-4);
  }
  .steps--stack .step__idx { grid-column: 1; grid-row: 1 / span 2; }
  .steps--stack .step__title,
  .steps--stack .step p { grid-column: 2; }
}

.step__idx {
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  color: var(--color-primary);
  letter-spacing: 0.1em;
}

.step__title {
  font-family: var(--font-body);
  font-size: var(--text-base);
  font-weight: 700;
}

.step p {
  font-size: var(--text-sm);
  color: var(--color-text-muted);
  max-width: 62ch;
}

/* ---------- table ---------- */
.table-wrap {
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  overflow-x: auto;
  background: var(--color-surface);
}

table.data {
  font-size: var(--text-sm);
  min-width: 620px;
  width: 100%;
  border-collapse: collapse;
}

table.data caption {
  text-align: left;
  padding: var(--space-5) var(--space-5) 0;
  font-size: var(--text-xs);
  color: var(--color-text-muted);
}

table.data th,
table.data td {
  text-align: left;
  padding: var(--space-4);
  border-bottom: 1px solid var(--color-divider);
  vertical-align: top;
}

table.data thead th {
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  font-weight: 500;
  letter-spacing: 0.09em;
  text-transform: uppercase;
  color: var(--color-text-muted);
  background: var(--color-surface-2);
}

table.data tbody tr:last-child th,
table.data tbody tr:last-child td {
  border-bottom: 0;
}

table.data tbody th {
  font-weight: 600;
  color: var(--color-text);
}

table.data td.num {
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  white-space: nowrap;
}

table.data tbody tr:hover td,
table.data tbody tr:hover th {
  background: var(--color-surface-2);
}

.pill {
  display: inline-block;
  font-family: var(--font-mono);
  font-size: 0.6875rem;
  letter-spacing: 0.06em;
  padding: 3px var(--space-2);
  border-radius: var(--radius-full);
  border: 1px solid var(--color-border);
  color: var(--color-text-muted);
  white-space: nowrap;
}

.pill--ok {
  color: var(--color-success);
  border-color: color-mix(in oklab, var(--color-success) 40%, transparent);
  background: color-mix(in oklab, var(--color-success) 8%, transparent);
}

/* ---------- chart ---------- */
.chart-card {
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  background: var(--color-surface);
  padding: var(--space-6);
}

.chart-card h3 {
  font-family: var(--font-body);
  font-size: var(--text-base);
  font-weight: 700;
  margin-bottom: var(--space-1);
}

.chart-card .cap {
  font-size: var(--text-xs);
  color: var(--color-text-muted);
  margin-bottom: var(--space-5);
}

.chart-box {
  position: relative;
  height: 320px;
}

/* ---------- callout ---------- */
.callout {
  border-left: 3px solid var(--color-primary);
  background: var(--color-surface-2);
  padding: var(--space-5) var(--space-6);
  border-radius: 0 var(--radius-md) var(--radius-md) 0;
}

.callout p {
  font-size: var(--text-sm);
  color: var(--color-text-muted);
  max-width: 68ch;
}

.callout strong {
  color: var(--color-text);
}

/* ---------- faq ---------- */
.faq {
  border-top: 1px solid var(--color-divider);
}

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

.faq summary {
  cursor: pointer;
  list-style: none;
  padding: var(--space-5) var(--space-8) var(--space-5) 0;
  font-weight: 600;
  font-size: var(--text-base);
  position: relative;
}

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

.faq summary::after {
  content: '';
  position: absolute;
  right: var(--space-2);
  top: 50%;
  width: 10px;
  height: 10px;
  border-right: 1.5px solid var(--color-text-muted);
  border-bottom: 1.5px solid var(--color-text-muted);
  transform: translateY(-70%) rotate(45deg);
  transition: transform var(--transition-interactive);
}

.faq details[open] summary::after {
  transform: translateY(-30%) rotate(225deg);
}

.faq summary:hover {
  color: var(--color-primary);
}

.faq p {
  font-size: var(--text-sm);
  color: var(--color-text-muted);
  padding-bottom: var(--space-5);
  max-width: 70ch;
}

/* ---------- page header ---------- */
.page-head {
  border-bottom: 1px solid var(--color-divider);
  background: var(--color-surface-2);
  padding-block: clamp(var(--space-12), 6vw, var(--space-20));
}

.page-head h1 {
  font-size: var(--text-xl);
  max-width: 26ch;
}

.crumb {
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--color-text-faint);
  margin-bottom: var(--space-4);
}

.crumb a {
  color: var(--color-text-muted);
  text-decoration: none;
}

.crumb a:hover {
  color: var(--color-primary);
}

/* ---------- cta band ---------- */
.cta {
  background: var(--color-text);
  color: var(--color-text-inverse);
}

.cta__inner {
  padding-block: clamp(var(--space-16), 7vw, var(--space-24));
  display: grid;
  gap: var(--space-8);
}

@media (min-width: 900px) {
  .cta__inner {
    grid-template-columns: minmax(0, 1fr) auto;
    align-items: center;
    gap: var(--space-16);
  }
}

.cta h2 {
  font-size: var(--text-xl);
  max-width: 24ch;
  color: var(--color-text-inverse);
}

.cta p {
  color: color-mix(in oklab, var(--color-text-inverse) 68%, transparent);
  font-size: var(--text-sm);
  margin-top: var(--space-4);
  max-width: 52ch;
}

.cta .btn--primary {
  background: var(--color-text-inverse);
  color: var(--color-text);
}

.cta .btn--primary:hover {
  background: #fff;
  color: #000;
}

.cta .btn--ghost {
  background: transparent;
  color: var(--color-text-inverse);
  border-color: color-mix(in oklab, var(--color-text-inverse) 30%, transparent);
}

.cta .btn--ghost:hover {
  border-color: var(--color-text-inverse);
  background: color-mix(in oklab, var(--color-text-inverse) 10%, transparent);
}

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

.field {
  display: grid;
  gap: var(--space-2);
}

.field label {
  font-size: var(--text-sm);
  font-weight: 600;
}

.field .hint {
  font-size: var(--text-xs);
  color: var(--color-text-muted);
}

.field input,
.field select,
.field textarea {
  width: 100%;
  padding: var(--space-3) var(--space-4);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  background: var(--color-surface);
  font-size: var(--text-sm);
  min-height: 46px;
}

.field textarea {
  min-height: 130px;
  resize: vertical;
  line-height: 1.6;
}

.field input:hover,
.field textarea:hover,
.field select:hover {
  border-color: var(--color-text-faint);
}

.field input:focus,
.field textarea:focus,
.field select:focus {
  border-color: var(--color-primary);
  outline: none;
  box-shadow: 0 0 0 3px var(--color-primary-highlight);
}

.field-row {
  display: grid;
  gap: var(--space-5);
}

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

.err {
  font-size: var(--text-xs);
  color: #b42318;
  display: none;
}

[data-theme='dark'] .err {
  color: #f97066;
}

.field[data-invalid='true'] .err {
  display: block;
}

.field[data-invalid='true'] input,
.field[data-invalid='true'] textarea {
  border-color: #b42318;
}

/* ---------- contact meta ---------- */
.meta-list {
  list-style: none;
  display: grid;
  gap: var(--space-6);
}

.meta-list dt,
.meta-list .k {
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--color-text-faint);
  margin-bottom: var(--space-2);
}

.meta-list .v {
  font-size: var(--text-sm);
  color: var(--color-text);
}

.meta-list .v a {
  font-weight: 600;
}

/* ---------- footer ---------- */
.footer {
  border-top: 1px solid var(--color-divider);
  background: var(--color-surface-2);
  padding-block: var(--space-16) var(--space-8);
  font-size: var(--text-sm);
}

.footer__grid {
  display: grid;
  gap: var(--space-10);
}

@media (min-width: 800px) {
  .footer__grid {
    grid-template-columns: 1.6fr 1fr 1fr 1.2fr;
    gap: var(--space-8);
  }
}

.footer__h {
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  font-weight: 500;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--color-text-faint);
  margin-bottom: var(--space-4);
}

.footer ul {
  list-style: none;
  display: grid;
  gap: var(--space-3);
}

.footer a {
  color: var(--color-text-muted);
  text-decoration: none;
}

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

.footer__blurb {
  color: var(--color-text-muted);
  font-size: var(--text-sm);
  max-width: 34ch;
  margin-top: var(--space-4);
}

.footer__bottom {
  margin-top: var(--space-12);
  padding-top: var(--space-6);
  border-top: 1px solid var(--color-divider);
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-4);
  justify-content: space-between;
  font-size: var(--text-xs);
  color: var(--color-text-faint);
}

.footer__bottom p {
  max-width: 70ch;
}

/* reveal on scroll */
.reveal {
  opacity: 0;
  transform: translateY(14px);
  transition:
    opacity 0.7s cubic-bezier(0.16, 1, 0.3, 1),
    transform 0.7s cubic-bezier(0.16, 1, 0.3, 1);
}

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

@media (prefers-reduced-motion: reduce) {
  .reveal {
    opacity: 1;
    transform: none;
  }
}

/* ---------- utilities (replace inline styles; CSP-safe) ---------- */
.u-text { color: var(--color-text) !important; }
.u-mb4 { margin-bottom: var(--space-4) !important; }
.u-mb5 { margin-bottom: var(--space-5) !important; }
.u-wrap { white-space: normal !important; }
.u-plainlink { text-decoration: none !important; color: inherit !important; }
.u-measure { max-width: var(--content-default) !important; }
.u-xs { font-size: var(--text-xs) !important; }
.u-pi0 { padding-inline: 0 !important; }
.u-h340 { height: 340px !important; }
.u-lg-mb6 { font-size: var(--text-lg) !important; margin-bottom: var(--space-6) !important; }
.form-status { font-size: var(--text-sm); color: var(--color-text-muted); min-height: 1.5em; }

/* ---- hero eyebrow spans both columns, lead-time note ---- */
.hero__eyebrow { grid-column: 1 / -1; margin-bottom: calc(-1 * var(--space-6)); }
.hero__note { font-size: var(--text-sm, 0.9375rem); color: var(--color-text-muted); }
.hero__note strong { color: var(--color-primary); font-weight: 700; }
.u-accent { color: var(--color-primary); text-transform: uppercase; }

/* ---- coating-free alternatives grid ---- */
.alt-grid {
  display: grid;
  grid-template-columns: 1fr;
  border-top: 1px solid var(--color-border);
  border-left: 1px solid var(--color-border);
}
@media (min-width: 640px) { .alt-grid { grid-template-columns: repeat(2, 1fr); } }
@media (min-width: 1100px) { .alt-grid { grid-template-columns: repeat(4, 1fr); } }
.alt {
  padding: var(--space-6) var(--space-5);
  border-right: 1px solid var(--color-border);
  border-bottom: 1px solid var(--color-border);
  background: var(--color-surface);
}
.alt__h { font-size: 1.0625rem; font-weight: 700; margin-bottom: var(--space-2); }
.alt p { font-size: 0.9375rem; line-height: 1.55; color: var(--color-text-muted); }
.alt:first-child { background: color-mix(in oklab, var(--color-primary) 7%, var(--color-surface)); }
.alt:first-child .alt__h { color: var(--color-primary); }

/* ---- lead-time card (materials) ---- */
.card .leadcard__value {
  font-family: var(--font-display);
  font-size: clamp(3rem, 6vw, 4.5rem) !important;
  color: var(--color-text);
  font-weight: 700;
  letter-spacing: -0.03em;
  line-height: 1;
  margin: var(--space-4) 0 var(--space-3);
}
.leadcard__steps { list-style: none; padding: 0; margin: var(--space-6) 0 0; border-top: 1px solid var(--color-divider); }
.leadcard__steps li { display: grid; grid-template-columns: 6.5rem 1fr; gap: var(--space-3); padding: var(--space-3) 0; border-bottom: 1px solid var(--color-divider); font-size: 0.9375rem; }
.leadcard__d { font-family: var(--font-mono); font-size: 0.8125rem; color: var(--color-primary); padding-top: 2px; }
#alt-h { max-width: 34ch; }
.flow-grid { display: grid; grid-template-columns: 1fr 1fr; gap: var(--space-6); align-items: start; }
@media (max-width: 800px) { .flow-grid { grid-template-columns: 1fr; } }
.flowcard--np { border-color: var(--color-primary); box-shadow: 0 0 0 1px var(--color-primary); }
.flowcard--wc .leadcard__d { color: var(--color-text-muted); }
.hp { position: absolute; left: -9999px; width: 1px; height: 1px; opacity: 0; }