/* Byterra main landing — system fonts, mobile-first */

:root {
  --color-bg: #fafafa;
  --color-surface: #ffffff;
  --color-text: #0c0c0d;
  --color-muted: #52525b;
  --color-border: #e4e4e7;
  --color-accent: #4f46e5;
  --color-accent-soft: rgba(79, 70, 229, 0.12);
  --gradient-hero: linear-gradient(
    135deg,
    rgba(79, 70, 229, 0.08) 0%,
    rgba(139, 92, 246, 0.06) 45%,
    rgba(250, 250, 250, 0) 70%
  );
  --radius: 12px;
  --radius-sm: 8px;
  --shadow: 0 1px 2px rgba(0, 0, 0, 0.04), 0 4px 24px rgba(0, 0, 0, 0.06);
  --font: system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto,
    "Helvetica Neue", Arial, sans-serif;
  --max: 68rem;
  --space-1: 0.25rem;
  --space-2: 0.5rem;
  --space-3: 1rem;
  --space-4: 1.5rem;
  --space-5: 2.5rem;
  --space-6: 4rem;
  --space-7: 6rem;
}

*,
*::before,
*::after {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

@media (prefers-reduced-motion: reduce) {
  html {
    scroll-behavior: auto;
  }
}

body {
  margin: 0;
  font-family: var(--font);
  font-size: 1rem;
  line-height: 1.6;
  color: var(--color-text);
  background: var(--color-bg);
  -webkit-font-smoothing: antialiased;
}

.skip-link {
  position: absolute;
  left: var(--space-3);
  top: -100px;
  z-index: 100;
  padding: var(--space-2) var(--space-3);
  background: var(--color-text);
  color: var(--color-surface);
  border-radius: var(--radius-sm);
  text-decoration: none;
  font-weight: 600;
}

.skip-link:focus {
  top: var(--space-3);
  outline: 2px solid var(--color-accent);
  outline-offset: 2px;
}

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

a {
  color: var(--color-accent);
  text-decoration-thickness: 1px;
  text-underline-offset: 0.2em;
}

a:hover {
  text-decoration-thickness: 2px;
}

.site-header {
  position: sticky;
  top: 0;
  z-index: 50;
  background: rgba(250, 250, 250, 0.85);
  backdrop-filter: blur(10px);
  border-bottom: 1px solid var(--color-border);
}

.site-header__inner {
  max-width: var(--max);
  margin: 0 auto;
  padding: var(--space-3) var(--space-4);
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-3);
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: var(--space-2);
  color: var(--color-text);
  text-decoration: none;
  font-weight: 700;
  letter-spacing: -0.02em;
}

.brand:hover {
  text-decoration: none;
}

.brand__mark {
  flex-shrink: 0;
}

.site-nav {
  display: flex;
  align-items: center;
  gap: var(--space-3);
  flex-wrap: wrap;
  justify-content: flex-end;
}

.site-nav a {
  color: var(--color-muted);
  font-size: 0.9375rem;
  font-weight: 500;
  text-decoration: none;
}

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

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 0.625rem 1.125rem;
  font-family: inherit;
  font-size: 0.9375rem;
  font-weight: 600;
  line-height: 1.25;
  border-radius: var(--radius-sm);
  border: none;
  cursor: pointer;
  text-decoration: none;
  transition: background 0.15s ease, transform 0.1s ease;
}

.btn:active {
  transform: scale(0.98);
}

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

.btn--primary:hover {
  background: #27272a;
  text-decoration: none;
}

.btn--primary:focus-visible {
  outline: 2px solid var(--color-accent);
  outline-offset: 2px;
}

.btn--ghost {
  background: transparent;
  color: var(--color-text);
  border: 1px solid var(--color-border);
}

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

main {
  overflow-x: hidden;
}

.section {
  max-width: var(--max);
  margin: 0 auto;
  padding: var(--space-6) var(--space-4);
}

.section--tight-top {
  padding-top: var(--space-5);
}

.hero {
  background: var(--gradient-hero);
  border-bottom: 1px solid var(--color-border);
}

.hero__inner {
  max-width: var(--max);
  margin: 0 auto;
  padding: var(--space-7) var(--space-4) var(--space-6);
}

.hero__eyebrow {
  font-size: 0.8125rem;
  font-weight: 600;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  color: var(--color-muted);
  margin: 0 0 var(--space-3);
}

.hero h1 {
  margin: 0 0 var(--space-4);
  font-size: clamp(1.875rem, 5vw, 2.75rem);
  font-weight: 700;
  letter-spacing: -0.03em;
  line-height: 1.15;
  max-width: 20ch;
}

.hero__sub {
  margin: 0 0 var(--space-5);
  font-size: 1.125rem;
  color: var(--color-muted);
  max-width: 42ch;
}

.download-badges {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: var(--space-4);
}

.download-badges__qr {
  width: 80px;
  height: 80px;
  display: block;
  flex-shrink: 0;
  border-radius: var(--radius-sm);
  background: var(--color-surface);
}

.download-badges__store {
  display: inline-flex;
  line-height: 0;
  text-decoration: none;
}

.download-badges__store:hover {
  text-decoration: none;
  opacity: 0.9;
}

.download-badges__store img {
  height: 40px;
  width: auto;
  display: block;
}

.cta-form {
  display: flex;
  flex-direction: column;
  gap: var(--space-3);
  max-width: 26rem;
}

@media (min-width: 480px) {
  .cta-form__row {
    display: flex;
    gap: var(--space-2);
    align-items: stretch;
  }

  .cta-form__row input {
    flex: 1;
    min-width: 0;
  }
}

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

.cta-form input[type="email"] {
  width: 100%;
  padding: 0.75rem 1rem;
  font-family: inherit;
  font-size: 1rem;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-sm);
  background: var(--color-surface);
}

.cta-form input[type="email"]:focus {
  border-color: var(--color-accent);
  outline: none;
  box-shadow: 0 0 0 3px var(--color-accent-soft);
}

.cta-form__hint {
  margin: 0;
  font-size: 0.8125rem;
  color: var(--color-muted);
}

.cta-form__error {
  margin: 0;
  font-size: 0.8125rem;
  color: #b91c1c;
  display: none;
}

.cta-form--invalid .cta-form__error {
  display: block;
}

.section h2 {
  margin: 0 0 var(--space-4);
  font-size: clamp(1.375rem, 3vw, 1.75rem);
  font-weight: 700;
  letter-spacing: -0.02em;
}

.section__lead {
  margin: 0 0 var(--space-5);
  color: var(--color-muted);
  max-width: 50ch;
}

.steps {
  display: grid;
  gap: var(--space-4);
  counter-reset: step;
  list-style: none;
  margin: 0;
  padding: 0;
}

@media (min-width: 640px) {
  .steps {
    grid-template-columns: repeat(3, 1fr);
    gap: var(--space-5);
  }
}

.steps li {
  position: relative;
  padding: var(--space-4);
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
}

.steps li::before {
  counter-increment: step;
  content: counter(step);
  display: flex;
  align-items: center;
  justify-content: center;
  width: 2rem;
  height: 2rem;
  margin-bottom: var(--space-3);
  font-size: 0.875rem;
  font-weight: 700;
  color: var(--color-surface);
  background: linear-gradient(135deg, #4f46e5, #7c3aed);
  border-radius: 999px;
}

.steps h3 {
  margin: 0 0 var(--space-2);
  font-size: 1.0625rem;
  font-weight: 600;
}

.steps p {
  margin: 0;
  font-size: 0.9375rem;
  color: var(--color-muted);
}

.benefits {
  display: grid;
  gap: var(--space-3);
  margin: 0;
  padding: 0;
  list-style: none;
}

@media (min-width: 640px) {
  .benefits {
    grid-template-columns: repeat(2, 1fr);
  }
}

.benefits li {
  padding: var(--space-4);
  border-left: 3px solid var(--color-accent);
  background: var(--color-surface);
  border-radius: 0 var(--radius-sm) var(--radius-sm) 0;
  border-top: 1px solid var(--color-border);
  border-right: 1px solid var(--color-border);
  border-bottom: 1px solid var(--color-border);
}

.benefits li strong {
  display: block;
  margin-bottom: var(--space-1);
  font-size: 1rem;
}

.benefits li span {
  font-size: 0.9375rem;
  color: var(--color-muted);
}

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

@media (min-width: 640px) {
  .pricing-grid {
    grid-template-columns: repeat(2, 1fr);
  }
}

.price-card {
  padding: var(--space-4);
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
}

.price-card h3 {
  margin: 0 0 var(--space-2);
  font-size: 1.125rem;
}

.price-card ul {
  margin: 0;
  padding-left: 1.25rem;
  color: var(--color-muted);
  font-size: 0.9375rem;
}

.price-card li {
  margin-bottom: var(--space-2);
}

.disclaimer {
  margin-top: var(--space-4);
  padding: var(--space-3);
  font-size: 0.8125rem;
  color: var(--color-muted);
  background: rgba(0, 0, 0, 0.03);
  border-radius: var(--radius-sm);
  border: 1px solid var(--color-border);
}

.faq {
  max-width: 48rem;
}

.faq details {
  padding: var(--space-3) 0;
  border-bottom: 1px solid var(--color-border);
}

.faq summary {
  font-weight: 600;
  cursor: pointer;
  list-style: none;
}

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

.faq summary::after {
  content: "+";
  float: right;
  color: var(--color-muted);
  font-weight: 400;
}

.faq details[open] summary::after {
  content: "−";
}

.faq p {
  margin: var(--space-3) 0 0;
  font-size: 0.9375rem;
  color: var(--color-muted);
}

.labs-grid {
  display: grid;
  gap: var(--space-3);
}

@media (min-width: 640px) {
  .labs-grid {
    grid-template-columns: repeat(2, 1fr);
  }
}

@media (min-width: 900px) {
  .labs-grid {
    grid-template-columns: repeat(4, 1fr);
  }
}

.lab-card {
  padding: var(--space-4);
  background: var(--color-surface);
  border: 1px dashed var(--color-border);
  border-radius: var(--radius);
  font-size: 0.875rem;
  color: var(--color-muted);
}

.lab-card h3 {
  margin: 0 0 var(--space-2);
  font-size: 0.9375rem;
  font-weight: 600;
  color: var(--color-text);
}

.lab-card p {
  margin: 0;
}

.site-footer {
  margin-top: var(--space-6);
  padding: var(--space-5) var(--space-4);
  border-top: 1px solid var(--color-border);
  background: var(--color-surface);
}

.site-footer__inner {
  max-width: var(--max);
  margin: 0 auto;
  display: flex;
  flex-direction: column;
  gap: var(--space-4);
}

@media (min-width: 640px) {
  .site-footer__inner {
    flex-direction: row;
    align-items: flex-start;
    justify-content: space-between;
  }
}

.site-footer p {
  margin: 0;
  font-size: 0.875rem;
  color: var(--color-muted);
}

.site-footer nav {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-3);
}

.site-footer a {
  font-size: 0.875rem;
  font-weight: 500;
}

/* Legal pages */
.legal-page {
  padding-bottom: var(--space-7);
}

.legal-page .section {
  padding-top: var(--space-5);
}

.legal-page article {
  max-width: 48rem;
}

.legal-page h1 {
  margin: 0 0 var(--space-2);
  font-size: clamp(1.5rem, 3vw, 2rem);
  font-weight: 700;
  letter-spacing: -0.02em;
}

.legal-meta {
  margin: 0 0 var(--space-5);
  font-size: 0.875rem;
  color: var(--color-muted);
}

.legal-page h2 {
  margin: var(--space-5) 0 var(--space-3);
  font-size: 1.125rem;
}

.legal-page h3 {
  margin: var(--space-4) 0 var(--space-2);
  font-size: 1rem;
}

.legal-page p,
.legal-page li {
  font-size: 0.9375rem;
  color: var(--color-muted);
}

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

.legal-page ul {
  padding-left: 1.25rem;
}

.legal-page .callout {
  margin: var(--space-4) 0;
  padding: var(--space-3);
  font-size: 0.9375rem;
  background: var(--color-accent-soft);
  border-radius: var(--radius-sm);
  border: 1px solid var(--color-border);
}