:root {
  --duo-green: #58CC02;
  --duo-green-light: #61E002;
  --duo-green-dark: #46A302;
  --duo-green-shadow: #58A700;
  --ink: #3C3C3C;
  --ink-strong: #4B4B4B;
  --muted: #777777;
  --muted-light: #AFAFAF;
  --canvas: #FFFFFF;
  --wash-blue: #DDF4FF;
  --surface: #FFFFFF;
  --border: #E5E5E5;
  --border-strong: #DADADA;
  --link-blue: #1CB0F6;
  --link-blue-dark: #1B99D6;
  --navy: #042C60;
  --super-navy: #100F3E;
  --footer-soft: #D7FFB8;
  --warning: #FFC800;
  --streak: #FF9600;
  --radius-control: 12px;
  --radius-lg: 16px;
  --radius-pill: 999px;
  --max: 988px;
  --wide: 1090px;
  --section-pad: 96px;
  --font-display: "Nunito", system-ui, sans-serif;
  --font-body: "Nunito", system-ui, sans-serif;
}

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

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  font-family: var(--font-body);
  font-size: 17px;
  font-weight: 500;
  line-height: 24px;
  color: var(--muted);
  background: var(--canvas);
  -webkit-font-smoothing: antialiased;
}

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

a {
  color: var(--link-blue);
  text-decoration: none;
}

a:hover {
  color: var(--link-blue-dark);
}

a:focus-visible,
button:focus-visible,
.btn:focus-visible {
  outline: 3px solid var(--link-blue);
  outline-offset: 2px;
}

.skip-link {
  position: absolute;
  left: -9999px;
  top: 0;
  z-index: 1000;
  padding: 12px 16px;
  background: var(--duo-green);
  color: #fff;
  font-weight: 700;
}

.skip-link:focus {
  left: 16px;
  top: 16px;
}

.container {
  width: 100%;
  max-width: var(--max);
  margin: 0 auto;
  padding: 0 24px;
}

.container--wide {
  max-width: var(--wide);
}

/* Header */
.site-header {
  height: 72px;
  display: flex;
  align-items: center;
  background: var(--canvas);
  border-bottom: 1px solid var(--border);
  position: sticky;
  top: 0;
  z-index: 50;
}

.site-header__inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  width: 100%;
}

.brand-lockup {
  display: flex;
  align-items: center;
  gap: 10px;
  text-decoration: none;
  color: var(--ink-strong);
}

.brand-lockup__mark {
  width: 40px;
  height: 40px;
  border-radius: 10px;
  background: var(--duo-green);
  display: flex;
  align-items: center;
  justify-content: center;
  box-shadow: 0 4px 0 var(--duo-green-shadow);
}

.brand-lockup__mark svg {
  width: 26px;
  height: 26px;
}

.brand-lockup__name {
  font-family: var(--font-display);
  font-size: 22px;
  font-weight: 800;
  letter-spacing: -0.02em;
  color: var(--duo-green);
}

.header-cta {
  font-size: 15px;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.02em;
}

/* Buttons */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 50px;
  padding: 0 24px;
  border-radius: var(--radius-control);
  font-size: 15px;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.02em;
  border: none;
  cursor: pointer;
  text-decoration: none;
  transition: transform 0.1s ease, background 0.15s ease, box-shadow 0.1s ease;
}

.btn--primary {
  background: var(--duo-green);
  color: #fff;
  box-shadow: 0 4px 0 var(--duo-green-shadow);
}

.btn--primary:hover {
  background: var(--duo-green-light);
  color: #fff;
}

.btn--primary:active {
  transform: translateY(4px);
  box-shadow: none;
}

.btn--secondary {
  background: var(--surface);
  color: var(--link-blue);
  border: 2px solid var(--border);
  box-shadow: 0 4px 0 var(--border-strong);
}

.btn--secondary:hover {
  background: var(--wash-blue);
  border-color: var(--link-blue);
  color: var(--link-blue-dark);
}

.btn--secondary:active {
  transform: translateY(4px);
  box-shadow: none;
}

.btn--block {
  width: 100%;
  max-width: 330px;
}

.btn--sm {
  min-height: 44px;
  padding: 0 16px;
  font-size: 13px;
}

/* Hero */
.hero {
  padding: 48px 0 40px;
}

.hero__grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 48px;
  align-items: center;
}

.hero__visual {
  position: relative;
  min-height: 320px;
}

.hero-illustration {
  width: 100%;
  max-width: 424px;
  margin: 0 auto;
}

.hero__copy {
  max-width: 480px;
}

.hero__eyebrow {
  display: inline-block;
  font-size: 13px;
  font-weight: 800;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  color: var(--link-blue);
  margin-bottom: 12px;
}

.hero__title {
  margin: 0 0 8px;
  font-family: var(--font-display);
  font-size: clamp(36px, 6vw, 56px);
  font-weight: 800;
  line-height: 1.1;
  letter-spacing: -0.02em;
  color: var(--duo-green);
}

.hero__product {
  margin: 0 0 16px;
  font-family: var(--font-display);
  font-size: clamp(22px, 3.5vw, 32px);
  font-weight: 800;
  line-height: 1.2;
  letter-spacing: -0.01em;
  color: var(--ink-strong);
}

.hero__lead {
  margin: 0 0 24px;
  max-width: 473px;
  color: var(--muted);
}

.hero__actions {
  display: flex;
  flex-direction: column;
  gap: 12px;
  align-items: flex-start;
}

.hero__bullets {
  list-style: none;
  margin: 24px 0 0;
  padding: 0;
}

.hero__bullets li {
  position: relative;
  padding-left: 32px;
  margin-bottom: 12px;
  color: var(--ink);
  font-weight: 600;
}

.hero__bullets li::before {
  content: "";
  position: absolute;
  left: 0;
  top: 2px;
  width: 22px;
  height: 22px;
  border-radius: 50%;
  background: var(--duo-green);
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 24 24' fill='white'%3E%3Cpath d='M9 16.2 4.8 12l-1.4 1.4L9 19 21 7l-1.4-1.4z'/%3E%3C/svg%3E");
  background-size: 14px;
  background-repeat: no-repeat;
  background-position: center;
}

/* Topic rail */
.topic-rail {
  border-top: 1px solid var(--border);
  border-bottom: 1px solid var(--border);
  padding: 20px 0;
  background: var(--surface);
}

.topic-rail__inner {
  display: flex;
  align-items: center;
  gap: 12px;
}

.topic-rail__label {
  flex-shrink: 0;
  font-size: 13px;
  font-weight: 800;
  text-transform: uppercase;
  color: var(--muted-light);
  letter-spacing: 0.04em;
}

.topic-rail__scroll {
  display: flex;
  gap: 10px;
  overflow-x: auto;
  scroll-snap-type: x mandatory;
  scrollbar-width: thin;
  padding: 4px 0;
  -webkit-overflow-scrolling: touch;
}

.topic-chip {
  flex-shrink: 0;
  scroll-snap-align: start;
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 10px 16px;
  border: 2px solid var(--border);
  border-radius: var(--radius-pill);
  font-size: 14px;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.02em;
  color: var(--ink);
  text-decoration: none;
  background: #fff;
  transition: border-color 0.15s, background 0.15s;
}

.topic-chip:hover {
  border-color: var(--duo-green);
  background: #f0ffe8;
  color: var(--ink-strong);
}

.topic-chip__icon {
  width: 20px;
  height: 20px;
  border-radius: 50%;
  background: var(--wash-blue);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 11px;
}

/* Sections */
.section {
  padding: var(--section-pad) 0;
}

.section--wash {
  background: var(--wash-blue);
}

.section__title {
  margin: 0 0 16px;
  font-family: var(--font-display);
  font-size: clamp(32px, 4vw, 48px);
  font-weight: 800;
  line-height: 1.25;
  letter-spacing: -0.005em;
  color: var(--duo-green);
}

.section__lead {
  margin: 0 0 32px;
  max-width: 520px;
}

.feature {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 48px;
  align-items: center;
}

.feature--reverse .feature__visual {
  order: 2;
}

.feature--reverse .feature__text {
  order: 1;
}

.feature__text h3 {
  margin: 0 0 12px;
  font-family: var(--font-display);
  font-size: 28px;
  font-weight: 800;
  color: var(--ink-strong);
  line-height: 1.3;
}

.feature__text p {
  margin: 0 0 20px;
  max-width: 473px;
}

.feature-card {
  background: var(--surface);
  border-radius: var(--radius-lg);
  border: 2px solid var(--border);
  padding: 24px;
  box-shadow: 0 4px 0 var(--border-strong);
}

.feature-card__bar {
  height: 12px;
  border-radius: var(--radius-pill);
  background: #e8e8e8;
  margin-bottom: 16px;
  overflow: hidden;
}

.feature-card__bar-fill {
  height: 100%;
  width: 72%;
  background: var(--duo-green);
  border-radius: var(--radius-pill);
}

.feature-card__nodes {
  display: flex;
  gap: 12px;
  flex-wrap: wrap;
}

.feature-node {
  width: 48px;
  height: 48px;
  border-radius: 50%;
  border: 3px solid var(--border);
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 800;
  font-size: 14px;
  color: var(--muted-light);
  background: #fff;
}

.feature-node--done {
  border-color: var(--duo-green);
  background: #e8ffd4;
  color: var(--duo-green-dark);
}

.feature-node--active {
  border-color: var(--link-blue);
  background: var(--wash-blue);
  color: var(--navy);
}

/* Trust */
.trust-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 24px;
}

.trust-card {
  text-align: center;
  padding: 32px 20px;
  background: var(--surface);
  border-radius: var(--radius-lg);
  border: 2px solid var(--border);
}

.trust-card__icon {
  width: 56px;
  height: 56px;
  margin: 0 auto 16px;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 28px;
}

.trust-card__icon--gov {
  background: var(--navy);
  color: #fff;
}

.trust-card__icon--lock {
  background: var(--duo-green);
  color: #fff;
}

.trust-card__icon--nih {
  background: var(--warning);
  color: var(--ink-strong);
}

.trust-card h3 {
  margin: 0 0 8px;
  font-size: 18px;
  font-weight: 800;
  color: var(--ink-strong);
}

.trust-card p {
  margin: 0;
  font-size: 15px;
  line-height: 22px;
}

/* Term preview grid */
.terms-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(200px, 1fr));
  gap: 16px;
}

.term-tile {
  padding: 20px;
  border-radius: var(--radius-control);
  background: var(--surface);
  border: 2px solid var(--border);
  text-decoration: none;
  color: inherit;
  transition: border-color 0.15s, transform 0.1s;
  box-shadow: 0 3px 0 var(--border-strong);
}

.term-tile:hover {
  border-color: var(--duo-green);
  transform: translateY(-2px);
  color: inherit;
}

.term-tile h4 {
  margin: 0 0 8px;
  font-size: 16px;
  font-weight: 800;
  color: var(--ink-strong);
}

.term-tile p {
  margin: 0;
  font-size: 14px;
  line-height: 20px;
}

/* Dark promo block */
.super-block {
  background: var(--super-navy);
  color: #fff;
  padding: 80px 0;
  text-align: center;
}

.super-block h2 {
  margin: 0 0 16px;
  font-family: var(--font-display);
  font-size: clamp(28px, 4vw, 40px);
  font-weight: 800;
  color: #fff;
}

.super-block p {
  margin: 0 auto 32px;
  max-width: 560px;
  color: #c8c8e8;
  font-size: 17px;
}

.super-block .btn--super {
  background: #fff;
  color: var(--super-navy);
  box-shadow: 0 4px 0 rgba(255, 255, 255, 0.25);
}

.super-block .btn--super:hover {
  background: #f5f5ff;
  color: var(--super-navy);
}

/* Final CTA */
.final-cta {
  padding: 80px 0 100px;
  text-align: center;
  background: linear-gradient(180deg, var(--canvas) 0%, #e8ffd4 40%, var(--duo-green) 100%);
}

.final-cta h2 {
  margin: 0 0 12px;
  font-family: var(--font-display);
  font-size: clamp(32px, 5vw, 48px);
  font-weight: 800;
  color: var(--ink-strong);
}

.final-cta p {
  margin: 0 auto 28px;
  max-width: 520px;
  color: var(--ink);
}

/* Footer */
.site-footer {
  background: var(--duo-green);
  color: #fff;
  padding: 48px 0 32px;
}

.footer__grid {
  display: grid;
  grid-template-columns: 2fr 1fr 1fr;
  gap: 40px;
  margin-bottom: 40px;
}

.footer__brand {
  font-family: var(--font-display);
  font-size: 24px;
  font-weight: 800;
  margin: 0 0 12px;
}

.footer__tagline {
  margin: 0;
  color: var(--footer-soft);
  font-size: 15px;
  max-width: 320px;
}

.footer h3 {
  margin: 0 0 16px;
  font-size: 15px;
  font-weight: 800;
  text-transform: uppercase;
  letter-spacing: 0.04em;
}

.footer ul {
  list-style: none;
  margin: 0;
  padding: 0;
}

.footer li {
  margin-bottom: 10px;
}

.footer a {
  color: var(--footer-soft);
  font-weight: 600;
  font-size: 15px;
}

.footer a:hover {
  color: #fff;
}

.footer__legal {
  border-top: 1px solid rgba(255, 255, 255, 0.25);
  padding-top: 24px;
  font-size: 13px;
  color: var(--footer-soft);
  line-height: 20px;
}

.footer__legal p {
  margin: 0 0 8px;
}

/* Responsive */
@media (max-width: 900px) {
  .hero__grid,
  .feature {
    grid-template-columns: 1fr;
    gap: 32px;
  }

  .feature--reverse .feature__visual,
  .feature--reverse .feature__text {
    order: unset;
  }

  .hero__visual {
    order: -1;
    min-height: 240px;
  }

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

  .footer__grid {
    grid-template-columns: 1fr;
    gap: 32px;
  }

  .header-cta.btn--primary {
    display: none;
  }

  :root {
    --section-pad: 64px;
  }
}

@media (max-width: 480px) {
  .hero__actions .btn--block {
    max-width: 100%;
  }
}