:root {
  --bg: #f8fafc;
  --surface: #ffffff;
  --surface-soft: #f1f5f9;
  --text: #0f172a;
  --muted: #475569;
  --muted-soft: #64748b;
  --border: #dbe3ef;
  --accent: #3157ff;
  --accent-dark: #243fc0;
  --accent-soft: #eef2ff;
  --danger: #b42318;
  --warning: #8a4b00;
  --warning-bg: #fff7e6;
  --success: #067647;
  --shadow: 0 24px 60px rgba(15, 23, 42, 0.08);
  --radius-lg: 28px;
  --radius-md: 18px;
  --radius-sm: 12px;
  --container: 1160px;
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  font-family: system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  color: var(--text);
  background: var(--bg);
  line-height: 1.55;
}

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

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

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

.container {
  width: min(100% - 40px, var(--container));
  margin-inline: auto;
}

.narrow {
  max-width: 840px;
}

.section {
  padding: 92px 0;
}

.site-header {
  position: sticky;
  top: 0;
  z-index: 20;
  background: rgba(248, 250, 252, 0.9);
  backdrop-filter: blur(18px);
  border-bottom: 1px solid rgba(219, 227, 239, 0.85);
}

.nav {
  min-height: 76px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 24px;
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  font-weight: 800;
  letter-spacing: -0.04em;
}

.brand-mark {
  display: grid;
  place-items: center;
  width: 38px;
  height: 38px;
  border-radius: 12px;
  background: var(--text);
  color: #ffffff;
  font-size: 0.78rem;
  letter-spacing: -0.02em;
}

.nav-links {
  display: flex;
  align-items: center;
  gap: 24px;
  color: var(--muted);
  font-weight: 600;
  font-size: 0.94rem;
}

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

.nav-cta {
  color: var(--accent) !important;
}

.nav-toggle {
  display: none;
  width: 42px;
  height: 42px;
  padding: 10px;
  border: 1px solid var(--border);
  border-radius: 12px;
  background: var(--surface);
  cursor: pointer;
}

.nav-toggle span {
  display: block;
  height: 2px;
  width: 100%;
  background: var(--text);
  margin: 5px 0;
}

.hero {
  position: relative;
  overflow: hidden;
  padding-top: 92px;
}

.hero::before {
  content: "";
  position: absolute;
  inset: -220px -160px auto auto;
  width: 520px;
  height: 520px;
  background: radial-gradient(circle, rgba(49, 87, 255, 0.18), transparent 66%);
  pointer-events: none;
}

.hero-grid {
  display: grid;
  grid-template-columns: 1.05fr 0.95fr;
  gap: 56px;
  align-items: center;
}

.eyebrow {
  margin: 0 0 14px;
  color: var(--accent);
  font-weight: 800;
  text-transform: uppercase;
  letter-spacing: 0.12em;
  font-size: 0.78rem;
}

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

h1 {
  margin-bottom: 22px;
  font-size: clamp(3rem, 7vw, 5.75rem);
  line-height: 0.95;
  letter-spacing: -0.08em;
}

h2 {
  margin-bottom: 18px;
  font-size: clamp(2rem, 4vw, 3.35rem);
  line-height: 1.02;
  letter-spacing: -0.065em;
}

h3 {
  margin-bottom: 10px;
  font-size: 1.1rem;
  letter-spacing: -0.035em;
}

.hero-subheadline,
.section-heading p,
.problem-section p,
.example-grid p,
.upload-copy p,
.final-cta-box p,
.privacy-grid > div:first-child p {
  color: var(--muted);
  font-size: 1.08rem;
}

.hero-subheadline {
  max-width: 690px;
  font-size: clamp(1.1rem, 2vw, 1.32rem);
}

.hero-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 14px;
  margin: 34px 0 18px;
}

.button {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 50px;
  padding: 0 20px;
  border-radius: 999px;
  font-weight: 800;
  border: 1px solid transparent;
  cursor: pointer;
  transition: transform 180ms ease, box-shadow 180ms ease, background 180ms ease;
}

.button:hover {
  transform: translateY(-1px);
}

.button-primary {
  background: var(--accent);
  color: #ffffff;
  box-shadow: 0 14px 28px rgba(49, 87, 255, 0.22);
}

.button-primary:hover {
  background: var(--accent-dark);
}

.button-secondary {
  background: var(--surface);
  color: var(--text);
  border-color: var(--border);
}

.full-width {
  width: 100%;
}

.hero-note {
  color: var(--muted-soft);
  font-weight: 600;
}

.hero-card {
  position: relative;
  border: 1px solid rgba(219, 227, 239, 0.9);
  border-radius: var(--radius-lg);
  padding: 24px;
  background: rgba(255, 255, 255, 0.88);
  box-shadow: var(--shadow);
}

.card-header {
  display: flex;
  align-items: center;
  gap: 10px;
  padding-bottom: 16px;
  margin-bottom: 18px;
  border-bottom: 1px solid var(--border);
  color: var(--muted);
  font-weight: 700;
}

.status-dot {
  width: 10px;
  height: 10px;
  border-radius: 999px;
  background: var(--success);
  box-shadow: 0 0 0 6px rgba(6, 118, 71, 0.12);
}

.mini-dashboard {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 14px;
}

.metric-card {
  padding: 18px;
  border-radius: var(--radius-md);
  background: var(--surface-soft);
}

.metric-card.wide {
  grid-column: 1 / -1;
  background: var(--accent-soft);
}

.metric-label {
  display: block;
  margin-bottom: 8px;
  color: var(--muted-soft);
  font-size: 0.84rem;
  font-weight: 700;
}

.metric-card strong {
  display: block;
  font-size: 1.08rem;
  line-height: 1.35;
}

.evidence-list {
  display: grid;
  gap: 10px;
  margin-top: 18px;
}

.evidence-list div {
  padding: 12px 14px;
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  background: #ffffff;
  color: var(--muted);
  font-size: 0.95rem;
}

.evidence-list span {
  display: inline-flex;
  margin-right: 6px;
  color: var(--text);
  font-weight: 800;
}

.problem-section {
  background: var(--surface);
  border-block: 1px solid var(--border);
}

.section-heading {
  max-width: 760px;
  margin-bottom: 42px;
}

.steps-grid,
.cards-grid,
.faq-grid {
  display: grid;
  gap: 18px;
}

.steps-grid {
  grid-template-columns: repeat(4, 1fr);
}

.step-card,
.info-card,
.hypothesis-card,
.diagnostic-form,
.safe-upload-box,
.final-cta-box,
.limit-box,
details {
  border: 1px solid var(--border);
  background: var(--surface);
  border-radius: var(--radius-md);
  box-shadow: 0 12px 30px rgba(15, 23, 42, 0.04);
}

.step-card {
  padding: 24px;
}

.step-number {
  display: grid;
  place-items: center;
  width: 40px;
  height: 40px;
  margin-bottom: 28px;
  border-radius: 13px;
  background: var(--accent-soft);
  color: var(--accent);
  font-weight: 900;
}

.step-card p,
.info-card p,
.faq-grid p,
.safe-upload-box li,
.form-disclaimer {
  color: var(--muted);
}

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

.info-card {
  padding: 24px;
}

.warning-card {
  background: var(--warning-bg);
  border-color: #ffdf99;
}

.warning-card h3 {
  color: var(--warning);
}

.example-section {
  background: var(--surface);
  border-block: 1px solid var(--border);
}

.example-grid,
.privacy-grid,
.upload-grid {
  display: grid;
  grid-template-columns: 0.9fr 1.1fr;
  gap: 56px;
  align-items: start;
}

.hypothesis-card {
  padding: 30px;
}

.hypothesis-label {
  display: inline-flex;
  margin-bottom: 18px;
  padding: 8px 12px;
  border-radius: 999px;
  background: var(--accent-soft);
  color: var(--accent);
  font-weight: 800;
  font-size: 0.84rem;
}

blockquote {
  margin: 0 0 24px;
  color: var(--text);
  font-size: 1.2rem;
  line-height: 1.6;
  letter-spacing: -0.02em;
}

.hypothesis-breakdown {
  display: grid;
  gap: 10px;
}

.hypothesis-breakdown div {
  padding: 14px;
  border-radius: var(--radius-sm);
  background: var(--surface-soft);
  color: var(--muted);
}

.limit-section {
  padding: 58px 0;
}

.limit-box {
  display: grid;
  grid-template-columns: 0.85fr 1.15fr;
  gap: 32px;
  padding: 34px;
  background: var(--text);
  color: #ffffff;
}

.limit-box .eyebrow,
.limit-box p {
  color: #c7d2fe;
}

.limit-box .button-primary {
  margin-top: 12px;
  background: #ffffff;
  color: var(--text);
  box-shadow: none;
}

.privacy-section {
  background: #0f172a;
  color: #ffffff;
}

.privacy-section .eyebrow,
.privacy-grid > div:first-child p {
  color: #c7d2fe;
}

.trust-list {
  display: grid;
  gap: 14px;
}

.trust-item {
  display: grid;
  grid-template-columns: 44px 1fr;
  gap: 16px;
  padding: 18px;
  border: 1px solid rgba(255, 255, 255, 0.14);
  border-radius: var(--radius-md);
  background: rgba(255, 255, 255, 0.06);
}

.trust-item span {
  display: grid;
  place-items: center;
  width: 38px;
  height: 38px;
  border-radius: 12px;
  background: rgba(255, 255, 255, 0.1);
  color: #c7d2fe;
  font-weight: 900;
  font-size: 0.8rem;
}

.trust-item p {
  margin: 0;
  color: #e2e8f0;
}

.upload-copy {
  position: sticky;
  top: 110px;
}

.safe-upload-box {
  padding: 22px;
  margin-top: 26px;
}

.safe-upload-box ul {
  margin: 12px 0 0;
  padding-left: 20px;
}

.safe-upload-box li + li {
  margin-top: 8px;
}

.diagnostic-form {
  padding: 28px;
}

.form-row {
  margin-bottom: 18px;
}

.two-columns {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 16px;
}

.field-group {
  display: grid;
  gap: 8px;
  margin-bottom: 18px;
}

label {
  color: var(--text);
  font-weight: 800;
  font-size: 0.92rem;
}

input[type="text"],
input[type="email"],
input[type="url"],
select,
textarea {
  width: 100%;
  border: 1px solid var(--border);
  border-radius: 14px;
  background: #ffffff;
  color: var(--text);
  padding: 13px 14px;
  outline: none;
  transition: border-color 150ms ease, box-shadow 150ms ease;
}

input:focus,
select:focus,
textarea:focus {
  border-color: var(--accent);
  box-shadow: 0 0 0 4px rgba(49, 87, 255, 0.12);
}

textarea {
  resize: vertical;
}

.file-field input[type="file"] {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  border: 0;
}

.file-dropzone {
  display: flex;
  align-items: center;
  gap: 16px;
  min-height: 130px;
  padding: 22px;
  border: 1.5px dashed #b7c4d8;
  border-radius: var(--radius-md);
  background: var(--surface-soft);
  cursor: pointer;
  transition: border-color 150ms ease, background 150ms ease;
}

.file-dropzone:hover,
.file-dropzone.is-dragging {
  border-color: var(--accent);
  background: var(--accent-soft);
}

.file-icon {
  display: grid;
  place-items: center;
  flex: 0 0 auto;
  width: 44px;
  height: 44px;
  border-radius: 14px;
  background: var(--accent);
  color: #ffffff;
  font-size: 1.4rem;
  font-weight: 800;
}

.file-dropzone strong,
.file-dropzone em {
  display: block;
}

.file-dropzone em {
  margin-top: 6px;
  color: var(--muted);
  font-style: normal;
  font-weight: 500;
}

.file-feedback {
  min-height: 24px;
  color: var(--muted);
  font-size: 0.94rem;
}

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

.file-feedback .warning {
  color: var(--warning);
  font-weight: 700;
}

.csv-preview {
  margin-bottom: 20px;
  border: 1px solid var(--border);
  border-radius: var(--radius-md);
  overflow: hidden;
  background: #ffffff;
}

.preview-header {
  display: flex;
  justify-content: space-between;
  gap: 16px;
  padding: 14px 16px;
  background: var(--surface-soft);
  border-bottom: 1px solid var(--border);
}

.preview-header span {
  color: var(--muted);
  font-weight: 700;
  font-size: 0.86rem;
}

.preview-table-wrap {
  overflow-x: auto;
}

.csv-preview table {
  width: 100%;
  border-collapse: collapse;
  font-size: 0.88rem;
}

.csv-preview th,
.csv-preview td {
  min-width: 120px;
  max-width: 220px;
  padding: 10px 12px;
  border-bottom: 1px solid var(--border);
  text-align: left;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

.csv-preview th {
  background: #ffffff;
  font-weight: 800;
}

.checkbox-group {
  margin-bottom: 16px;
}

.checkbox-group label {
  display: grid;
  grid-template-columns: 20px 1fr;
  gap: 10px;
  align-items: start;
  color: var(--muted);
  font-weight: 600;
}

.checkbox-group input {
  margin-top: 3px;
  width: 18px;
  height: 18px;
  accent-color: var(--accent);
}

.field-error {
  min-height: 18px;
  color: var(--danger);
  font-weight: 700;
}

.has-error input,
.has-error select,
.has-error textarea,
.has-error .file-dropzone {
  border-color: var(--danger);
}

.form-disclaimer {
  margin: 14px 0 0;
  font-size: 0.86rem;
}

.faq-section {
  background: var(--surface);
  border-top: 1px solid var(--border);
}

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

details {
  padding: 20px 22px;
}

summary {
  cursor: pointer;
  font-weight: 800;
  letter-spacing: -0.02em;
}

details p {
  margin: 12px 0 0;
}

.final-cta-section {
  padding-top: 70px;
}

.final-cta-box {
  padding: 48px;
  text-align: center;
  background: linear-gradient(180deg, #ffffff 0%, #f4f7ff 100%);
}

.final-cta-box p {
  max-width: 660px;
  margin-inline: auto;
}

.site-footer {
  padding: 42px 0;
  background: #ffffff;
  border-top: 1px solid var(--border);
}

.footer-grid {
  display: flex;
  justify-content: space-between;
  gap: 28px;
  color: var(--muted);
}

.footer-grid p {
  margin: 12px 0 0;
}

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

.hidden {
  display: none !important;
}

@media (max-width: 980px) {
  .section {
    padding: 72px 0;
  }

  .hero-grid,
  .example-grid,
  .privacy-grid,
  .upload-grid,
  .limit-box {
    grid-template-columns: 1fr;
  }

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

  .upload-copy {
    position: static;
  }
}

@media (max-width: 760px) {
  .container {
    width: min(100% - 28px, var(--container));
  }

  .nav-links {
    position: absolute;
    inset: 76px 14px auto;
    display: none;
    flex-direction: column;
    align-items: stretch;
    gap: 0;
    padding: 12px;
    border: 1px solid var(--border);
    border-radius: var(--radius-md);
    background: #ffffff;
    box-shadow: var(--shadow);
  }

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

  .nav-links a {
    padding: 14px;
    border-radius: 12px;
  }

  .nav-links a:hover {
    background: var(--surface-soft);
  }

  .nav-toggle {
    display: block;
  }

  .hero {
    padding-top: 62px;
  }

  h1 {
    font-size: clamp(2.75rem, 15vw, 4.2rem);
  }

  .hero-actions,
  .button {
    width: 100%;
  }

  .mini-dashboard,
  .steps-grid,
  .diagnostic-grid,
  .faq-grid,
  .two-columns {
    grid-template-columns: 1fr;
  }

  .diagnostic-form,
  .hypothesis-card,
  .final-cta-box,
  .limit-box {
    padding: 24px;
  }

  .footer-grid {
    flex-direction: column;
  }
}

@media (max-width: 480px) {
  .section {
    padding: 58px 0;
  }

  .hero-card,
  .diagnostic-form {
    border-radius: 22px;
    padding: 20px;
  }

  blockquote {
    font-size: 1.05rem;
  }

  .file-dropzone {
    align-items: flex-start;
  }
}