:root {
  --black: #000000;
  --white: #ffffff;
  --gray: #ededed;
  --muted: #6a6a6a;
  --line: rgba(0, 0, 0, 0.12);
  --space: clamp(20px, 5vw, 72px);
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  color: var(--black);
  background: var(--white);
  font-family: Montserrat, sans-serif;
  font-weight: 300;
  line-height: 1.6;
}

img,
svg {
  display: block;
}

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

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

h1,
h2,
h3,
strong {
  font-weight: 500;
  letter-spacing: -0.03em;
}

h1,
h2,
h3,
p {
  margin: 0;
}

h1 {
  font-size: clamp(2rem, 6vw, 4.6rem);
  line-height: 1.08;
  max-width: 16ch;
}

h2 {
  font-size: clamp(1.45rem, 3.4vw, 2.4rem);
  line-height: 1.18;
  max-width: 22ch;
}

h3 {
  font-weight: 400;
  font-size: 1.15rem;
  line-height: 1.3;
}

.dot-grid {
  position: fixed;
  inset: 0;
  z-index: -1;
  pointer-events: none;
  background-image: radial-gradient(rgba(0, 0, 0, 0.08) 0.7px, transparent 0.8px);
  background-size: 18px 18px;
  mask-image: linear-gradient(180deg, rgba(0, 0, 0, 0.45), transparent 28%, transparent 72%, rgba(0, 0, 0, 0.2));
}

.site-header {
  position: sticky;
  top: 0;
  z-index: 20;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  padding: 16px var(--space);
  background: rgba(255, 255, 255, 0.92);
  border-bottom: 1px solid var(--line);
  backdrop-filter: blur(10px);
}

.brand {
  display: flex;
  align-items: center;
  gap: 10px;
}

.brand-mark {
  width: 34px;
  height: 34px;
  min-width: 34px;
}

.brand-lockup {
  display: grid;
  line-height: 1;
  text-transform: uppercase;
}

.brand-lockup span:first-child {
  font-size: 11px;
  font-weight: 500;
  letter-spacing: 0.18em;
}

.brand-lockup span:last-child {
  font-size: 10px;
  font-weight: 300;
  letter-spacing: 0.32em;
}

.nav-links {
  display: none;
  gap: 28px;
  font-size: 13px;
  font-weight: 400;
  letter-spacing: 0.04em;
}

.header-cta,
.button {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 44px;
  padding: 0 18px;
  border: 1px solid var(--black);
  background: var(--black);
  color: var(--white);
  font-size: 12px;
  font-weight: 500;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  cursor: pointer;
}

.button.ghost,
.header-cta {
  background: transparent;
  color: var(--black);
}

.button.primary {
  background: var(--black);
  color: var(--white);
}

.header-cta {
  display: none;
}

main {
  padding: 0 var(--space) 80px;
}

.hero,
.section {
  max-width: 1120px;
  margin: 0 auto;
  padding: 72px 0;
  border-bottom: 1px solid var(--line);
}

.eyebrow {
  margin-bottom: 18px;
  font-size: 11px;
  font-weight: 500;
  letter-spacing: 0.18em;
  text-transform: uppercase;
}

.lead,
.prose p,
.section-heading p,
.model-detail p,
.cases p {
  color: var(--muted);
  font-size: 1.02rem;
}

.lead {
  max-width: 46ch;
  margin-top: 22px;
}

.hero-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: 32px;
}

.hero-note {
  margin-top: 22px;
  color: var(--muted);
  font-size: 13px;
}

.section-heading {
  display: grid;
  gap: 14px;
  margin-bottom: 36px;
}

.signal-list {
  display: grid;
  gap: 0;
  padding: 0;
  margin: 0;
  list-style: none;
}

.signal-list li {
  padding: 18px 0;
  border-top: 1px solid var(--line);
  font-size: 1.05rem;
}

.split {
  display: grid;
  gap: 28px;
}

.prose {
  display: grid;
  gap: 16px;
  max-width: 54ch;
}

.statement {
  color: var(--black) !important;
  font-weight: 500;
  letter-spacing: 0.04em;
}

.model-grid {
  display: grid;
  gap: 10px;
}

.model-card {
  display: grid;
  gap: 6px;
  padding: 18px;
  text-align: left;
  background: var(--white);
  border: 1px solid var(--line);
}

.model-card span {
  font-size: 11px;
  letter-spacing: 0.16em;
}

.model-card em {
  color: var(--muted);
  font-style: normal;
  font-size: 13px;
}

.model-card.is-active {
  background: var(--black);
  color: var(--white);
}

.model-card.is-active em {
  color: #cfcfcf;
}

.model-detail {
  margin-top: 18px;
  padding: 24px;
  background: var(--gray);
}

.model-detail h3 {
  margin-bottom: 10px;
}

.cases {
  display: grid;
  gap: 16px;
}

.cases article {
  padding: 24px 0;
  border-top: 1px solid var(--line);
}

.case-label {
  margin-bottom: 10px;
  font-size: 11px;
  font-weight: 500;
  letter-spacing: 0.16em;
  text-transform: uppercase;
}

.cases h3 {
  max-width: 28ch;
  margin-bottom: 10px;
}

.diagnostic-form,
.contact-form,
.result-panel {
  max-width: 720px;
}

.step-meta {
  font-size: 12px;
  letter-spacing: 0.12em;
  text-transform: uppercase;
}

.progress {
  height: 1px;
  margin: 14px 0 28px;
  background: var(--gray);
}

.progress span {
  display: block;
  width: 16.6%;
  height: 100%;
  background: var(--black);
  transition: width 180ms ease;
}

fieldset {
  margin: 0;
  padding: 0;
  border: 0;
}

legend {
  padding: 0;
  margin-bottom: 18px;
  font-size: 1.25rem;
  font-weight: 500;
  letter-spacing: -0.03em;
}

.option-grid {
  display: grid;
  gap: 8px;
}

.option-grid label,
.fields label,
.contact-form label {
  display: flex;
  gap: 10px;
  align-items: center;
  padding: 14px 16px;
  border: 1px solid var(--line);
  background: var(--white);
  cursor: pointer;
}

.fields label,
.contact-form label {
  display: grid;
  gap: 8px;
  cursor: default;
  font-size: 12px;
  letter-spacing: 0.08em;
  text-transform: uppercase;
}

.fields,
.contact-form {
  display: grid;
  gap: 10px;
}

input,
textarea {
  width: 100%;
  padding: 0;
  border: 0;
  background: transparent;
  outline: none;
  text-transform: none;
  letter-spacing: 0;
  font-size: 15px;
  font-weight: 300;
}

.hint,
.form-note {
  color: var(--muted);
  font-size: 13px;
}

.hint {
  margin: 8px 0 16px;
}

.hint a,
.form-note a,
.site-footer a {
  text-decoration: underline;
  text-underline-offset: 3px;
}

.form-nav {
  display: flex;
  gap: 10px;
  margin-top: 22px;
}

.result-panel {
  margin-top: 36px;
  padding: 28px;
  background: var(--gray);
}

.result-stack {
  display: grid;
  gap: 18px;
  margin: 18px 0 8px;
}

.result-stack article strong {
  display: block;
  margin-bottom: 6px;
  font-size: 11px;
  letter-spacing: 0.16em;
  text-transform: uppercase;
}

.site-footer {
  display: grid;
  gap: 18px;
  padding: 36px var(--space) 48px;
  border-top: 1px solid var(--line);
  font-size: 13px;
}

.site-footer div:nth-child(2) {
  display: flex;
  flex-wrap: wrap;
  gap: 16px;
}

.legal {
  max-width: 720px;
  margin: 0 auto;
  padding: 80px var(--space) 100px;
}

.legal h1 {
  font-size: 2rem;
  margin-bottom: 18px;
}

.legal p + p {
  margin-top: 14px;
}

@media (min-width: 760px) {
  .nav-links,
  .header-cta {
    display: flex;
  }

  .hero,
  .section {
    padding: 96px 0;
  }

  .split {
    grid-template-columns: 0.9fr 1.1fr;
    align-items: start;
  }

  .model-grid {
    grid-template-columns: repeat(5, 1fr);
  }

  .cases {
    grid-template-columns: repeat(2, 1fr);
    gap: 0 36px;
  }

  .option-grid {
    grid-template-columns: 1fr 1fr;
  }

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

  .fields {
    grid-template-columns: 1fr 1fr;
  }

  .site-footer {
    grid-template-columns: 1fr auto auto;
    align-items: end;
  }
}