/* ==========================================================================
   BioGrid Networks — Main Stylesheet
   Design System: Industrial, Structured, Measured, Controlled
   ========================================================================== */

/* --------------------------------------------------------------------------
   1. CSS CUSTOM PROPERTIES
   -------------------------------------------------------------------------- */
:root {
  /* Colors */
  --color-bg:           #F5F5F2;
  --color-bg-alt:       #F2F1EC;
  --color-navy:         #0B1F2D;
  --color-navy-hover:   #153449;
  --color-steel:        #3E5C76;
  --color-copper:       #8A4F2A;
  --color-text:         #1A2B38;
  --color-text-muted:   #4A5E6D;
  --color-text-light:   #F5F5F2;
  --color-border:       #D4D0C8;
  --color-border-dark:  #2A3F52;

  /* Typography */
  --font-primary:   'Inter', 'IBM Plex Sans', sans-serif;
  --font-heading:   'IBM Plex Sans', 'Inter', sans-serif;

  /* Spacing */
  --section-padding:    96px;
  --container-max:      1100px;
  --container-padding:  24px;

  /* Transitions */
  --transition-base:    0.2s ease;
}

/* --------------------------------------------------------------------------
   2. RESET & BASE
   -------------------------------------------------------------------------- */
*, *::before, *::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

html {
  scroll-behavior: smooth;
  font-size: 16px;
}

body {
  font-family: var(--font-primary);
  background-color: #E8E6DF;
  color: var(--color-text);
  line-height: 1.7;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

/* --------------------------------------------------------------------------
   SITE SHELL — fixed 1100px column, centred on page
   -------------------------------------------------------------------------- */
.site-shell {
  max-width: var(--container-max);
  width: 100%;
  margin: 0 auto;
  background-color: var(--color-bg);
  box-shadow: 0 0 0 1px rgba(0,0,0,0.08), 0 4px 32px rgba(0,0,0,0.10);
  position: relative;
  overflow-x: clip;
}

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

a {
  color: inherit;
  text-decoration: none;
  transition: color var(--transition-base), opacity var(--transition-base);
}

ul {
  list-style: none;
}

strong {
  font-weight: 600;
}

/* --------------------------------------------------------------------------
   3. LAYOUT — CONTAINER
   -------------------------------------------------------------------------- */
.container {
  max-width: var(--container-max);
  margin-left: auto;
  margin-right: auto;
  padding-left: var(--container-padding);
  padding-right: var(--container-padding);
  width: 100%;
}

/* --------------------------------------------------------------------------
   4. TYPOGRAPHY SYSTEM
   -------------------------------------------------------------------------- */
h1, h2, h3, h4 {
  font-family: var(--font-heading);
  line-height: 1.2;
  letter-spacing: -0.01em;
  text-align: center;
}

h1 { font-size: clamp(2rem, 4vw, 3rem);    font-weight: 700; }
h2 { font-size: clamp(1.5rem, 3vw, 2.1rem); font-weight: 600; }
h3 { font-size: 1.15rem;                    font-weight: 600; }

p  { font-size: 1rem; font-weight: 400; }

/* --------------------------------------------------------------------------
   5. SECTION UTILITIES
   -------------------------------------------------------------------------- */
.section {
  padding: var(--section-padding) 0;
  text-align: center;
}

.section--alt {
  background-color: var(--color-bg-alt);
}

.section--cta {
  background-color: var(--color-navy);
}

.section-header {
  margin-bottom: 56px;
}

.section__title {
  color: var(--color-navy);
  margin-bottom: 16px;
}

.section__title--light {
  color: var(--color-text-light);
}

.section__lead {
  font-size: 1.15rem;
  font-weight: 500;
  color: var(--color-text);
  max-width: 700px;
  margin: 0 auto 24px;
  text-align: center;
}

.section__lead--light {
  color: rgba(245, 245, 242, 0.9);
}

.section__body {
  font-size: 1rem;
  color: var(--color-text-muted);
  text-align: center;
  margin-bottom: 40px;
}

.section__note {
  font-size: 0.9rem;
  color: var(--color-text-muted);
  margin-top: 40px;
  font-style: italic;
  text-align: center;
}

/* Section Divider */
.section-divider {
  width: 48px;
  height: 3px;
  background-color: var(--color-copper);
  margin: 0 auto;
}

.section-divider--light {
  background-color: rgba(245, 245, 242, 0.4);
}

/* --------------------------------------------------------------------------
   6. BUTTONS
   -------------------------------------------------------------------------- */
.btn {
  display: inline-block;
  padding: 13px 32px;
  font-family: var(--font-primary);
  font-size: 0.95rem;
  font-weight: 600;
  letter-spacing: 0.04em;
  text-transform: uppercase;
  border: 2px solid transparent;
  cursor: pointer;
  transition: background-color var(--transition-base), color var(--transition-base), border-color var(--transition-base);
  text-align: center;
}

.btn--primary {
  background-color: var(--color-navy);
  color: var(--color-text-light);
  border-color: var(--color-navy);
}

.btn--primary:hover {
  background-color: var(--color-navy-hover);
  border-color: var(--color-navy-hover);
  color: var(--color-text-light);
}

.btn--outline {
  background-color: transparent;
  color: var(--color-text-light);
  border-color: rgba(245, 245, 242, 0.6);
}

.btn--outline:hover {
  background-color: rgba(245, 245, 242, 0.1);
  border-color: var(--color-text-light);
  color: var(--color-text-light);
}

/* --------------------------------------------------------------------------
   7. NAVIGATION
   -------------------------------------------------------------------------- */
.nav {
  position: sticky;
  top: 0;
  z-index: 1000;
  background-color: var(--color-navy);
  border-bottom: 1px solid var(--color-border-dark);
}

.nav__inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 64px;
}

.nav__brand {
  font-family: var(--font-heading);
  font-size: 1.05rem;
  font-weight: 700;
  letter-spacing: 0.02em;
  text-transform: uppercase;
  display: flex;
  align-items: center;
  gap: 10px;
}

.nav__logo {
  height: 32px;
  width: auto;
  display: block;
  flex-shrink: 0;
}

.nav__brand-primary {
  color: var(--color-text-light);
}

.nav__brand-secondary {
  color: var(--color-steel);
}

.nav__links {
  display: flex;
  align-items: center;
  gap: 32px;
}

.nav__links li a {
  color: rgba(245, 245, 242, 0.75);
  font-size: 0.85rem;
  font-weight: 500;
  letter-spacing: 0.06em;
  text-transform: uppercase;
}

.nav__links li a:hover,
.nav__links li a.active {
  color: var(--color-text-light);
}

.nav__links li a.active {
  border-bottom: 2px solid var(--color-steel);
  padding-bottom: 2px;
}

.nav__cta {
  background-color: var(--color-steel);
  color: var(--color-text-light) !important;
  padding: 8px 18px;
  font-size: 0.82rem !important;
  letter-spacing: 0.06em;
  transition: background-color var(--transition-base);
}

.nav__cta:hover {
  background-color: #4f7496 !important;
}

.nav__toggle {
  display: none;
  background: none;
  border: none;
  color: var(--color-text-light);
  font-size: 1.2rem;
  cursor: pointer;
  padding: 4px 8px;
}

/* --------------------------------------------------------------------------
   8. HERO SECTION
   -------------------------------------------------------------------------- */
.hero {
  padding: 104px 0 96px;
  text-align: center;
  background-color: var(--color-bg);
  border-bottom: 1px solid var(--color-border);
}

.hero__inner {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 0;
}

.hero__program-label {
  font-size: 0.8rem;
  font-weight: 500;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--color-steel);
  margin-bottom: 20px;
}

.hero__title {
  color: var(--color-navy);
  margin-bottom: 24px;
}

/* divider placed by section-divider class */
.hero__inner .section-divider {
  margin-bottom: 36px;
}

.hero__subtitle {
  font-size: 1.2rem;
  font-weight: 500;
  color: var(--color-text);
  max-width: 680px;
  margin: 0 auto 20px;
}

.hero__body {
  font-size: 1rem;
  color: var(--color-text-muted);
  max-width: 580px;
  margin: 0 auto 40px;
}

/* --------------------------------------------------------------------------
   9. THE PROBLEM SECTION
   -------------------------------------------------------------------------- */
.problem-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 32px;
  margin: 48px auto;
  max-width: 900px;
}

.problem-item {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 16px;
  padding: 36px 24px;
  background-color: var(--color-bg-alt);
  border: 1px solid var(--color-border);
  border-top: 3px solid var(--color-steel);
  text-align: center;
}

.problem-item__icon {
  width: 52px;
  height: 52px;
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--color-steel);
  font-size: 1.4rem;
}

.problem-item p {
  font-size: 0.95rem;
  color: var(--color-text-muted);
  font-weight: 500;
}

.callout {
  max-width: 640px;
  margin: 0 auto;
  padding: 36px 40px;
  border-left: 3px solid var(--color-copper);
  border-right: 3px solid var(--color-copper);
  background-color: var(--color-bg-alt);
  text-align: center;
}

.callout p {
  font-size: 1rem;
  color: var(--color-text-muted);
  margin-bottom: 12px;
}

.callout p:last-child {
  margin-bottom: 0;
}

.callout__emphasis {
  font-size: 1.05rem !important;
  font-weight: 600 !important;
  color: var(--color-navy) !important;
}

/* --------------------------------------------------------------------------
   10. WHAT BIOGRID IS — CARDS
   -------------------------------------------------------------------------- */
.card-row {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 28px;
  margin: 0 auto 56px;
  max-width: 960px;
}

.card {
  display: flex;
  flex-direction: column;
  align-items: center;
  padding: 40px 28px;
  background-color: var(--color-bg);
  border: 1px solid var(--color-border);
  border-bottom: 3px solid var(--color-steel);
  text-align: center;
}

.card__icon {
  width: 56px;
  height: 56px;
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--color-steel);
  font-size: 1.5rem;
  margin-bottom: 20px;
}

.card__title {
  color: var(--color-navy);
  margin-bottom: 12px;
  font-size: 1rem;
  letter-spacing: 0.04em;
  text-transform: uppercase;
}

.card__text {
  font-size: 0.95rem;
  color: var(--color-text-muted);
  line-height: 1.6;
}

/* Exclusion Block */
.exclusion-block {
  max-width: 560px;
  margin: 0 auto;
  padding: 32px 40px;
  background-color: var(--color-bg);
  border: 1px solid var(--color-border);
  text-align: center;
}

.exclusion-block__label {
  font-size: 0.72rem;
  font-weight: 600;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--color-copper);
  margin-bottom: 16px;
}

.exclusion-list {
  display: flex;
  flex-direction: column;
  gap: 10px;
  width: fit-content;
  margin: 0 auto;
}

.exclusion-list li {
  display: flex;
  align-items: baseline;
  justify-content: flex-start;
  gap: 12px;
  font-size: 0.9rem;
  color: var(--color-text-muted);
  text-align: left;
}

.exclusion-list li i {
  color: var(--color-copper);
  font-size: 0.7rem;
  flex-shrink: 0;
  width: 12px;
  text-align: center;
  margin-top: 3px;
}

.exclusion-list li span {
  flex: 1;
}

/* --------------------------------------------------------------------------
   11. HOW IT WORKS
   -------------------------------------------------------------------------- */
.how-grid {
  display: grid;
  grid-template-columns: 1fr 40px 1fr 40px 1fr;
  align-items: start;
  gap: 0;
  max-width: 1000px;
  margin: 0 auto;
}

.how-block {
  display: flex;
  flex-direction: column;
  align-items: center;
  padding: 40px 28px;
  background-color: var(--color-bg-alt);
  border: 1px solid var(--color-border);
  border-top: 3px solid var(--color-navy);
  text-align: center;
  height: 100%;
}

.how-block__num {
  font-size: 0.72rem;
  font-weight: 700;
  letter-spacing: 0.16em;
  color: var(--color-copper);
  margin-bottom: 16px;
}

.how-block__icon {
  width: 52px;
  height: 52px;
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--color-steel);
  font-size: 1.4rem;
  margin-bottom: 20px;
  border: 1px solid var(--color-border);
  background-color: var(--color-bg);
}

.how-block__title {
  color: var(--color-navy);
  font-size: 1rem;
  text-transform: uppercase;
  letter-spacing: 0.04em;
  margin-bottom: 8px;
}

.how-block__sub {
  font-size: 0.85rem;
  color: var(--color-steel);
  font-weight: 500;
  margin-bottom: 20px;
  font-style: italic;
}

.how-block__list {
  text-align: left;
  display: flex;
  flex-direction: column;
  gap: 8px;
}

.how-block__list li {
  font-size: 0.9rem;
  color: var(--color-text-muted);
  padding-left: 14px;
  position: relative;
}

.how-block__list li::before {
  content: '—';
  position: absolute;
  left: 0;
  color: var(--color-steel);
  font-size: 0.75rem;
}

.how-connector {
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--color-border);
  font-size: 1rem;
  padding-top: 80px;
}

/* --------------------------------------------------------------------------
   12. DEVELOPMENT STAGE
   -------------------------------------------------------------------------- */
.trl-block {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 8px;
  margin: 0 auto 48px;
}

.trl-badge {
  display: inline-block;
  padding: 12px 36px;
  background-color: var(--color-navy);
  color: var(--color-text-light);
  font-family: var(--font-heading);
  font-size: 1.5rem;
  font-weight: 700;
  letter-spacing: 0.06em;
}

.trl-label {
  font-size: 0.8rem;
  font-weight: 500;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--color-text-muted);
}

.focus-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 24px;
  max-width: 880px;
  margin: 0 auto;
}

.focus-item {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 14px;
  padding: 32px 20px;
  background-color: var(--color-bg);
  border: 1px solid var(--color-border);
  text-align: center;
}

.focus-item i {
  color: var(--color-steel);
  font-size: 1.3rem;
}

.focus-item span {
  font-size: 0.88rem;
  color: var(--color-text-muted);
  font-weight: 500;
  line-height: 1.4;
}

/* --------------------------------------------------------------------------
   13. VALIDATION TARGETS
   -------------------------------------------------------------------------- */
.metrics-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 24px;
  max-width: 960px;
  margin: 0 auto;
}

.metric {
  display: flex;
  flex-direction: column;
  align-items: center;
  padding: 40px 20px;
  background-color: var(--color-bg-alt);
  border: 1px solid var(--color-border);
  border-top: 3px solid var(--color-navy);
  text-align: center;
}

.metric__value {
  font-family: var(--font-heading);
  font-size: 1.8rem;
  font-weight: 700;
  color: var(--color-navy);
  margin-bottom: 12px;
  line-height: 1;
}

.metric__label {
  font-size: 0.82rem;
  font-weight: 500;
  color: var(--color-text-muted);
  letter-spacing: 0.04em;
  line-height: 1.4;
}

/* --------------------------------------------------------------------------
   14. DEPLOYMENT / SECTOR GRID
   -------------------------------------------------------------------------- */
.sector-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 20px;
  max-width: 800px;
  margin: 0 auto;
}

.sector-item {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 14px;
  padding: 32px 16px;
  background-color: var(--color-bg);
  border: 1px solid var(--color-border);
  text-align: center;
  transition: border-color var(--transition-base);
}

.sector-item:hover {
  border-color: var(--color-steel);
}

.sector-item i {
  color: var(--color-steel);
  font-size: 1.4rem;
}

.sector-item span {
  font-size: 0.85rem;
  font-weight: 600;
  color: var(--color-navy);
  letter-spacing: 0.04em;
  text-transform: uppercase;
}

/* --------------------------------------------------------------------------
   15. PILOT CTA SECTION
   -------------------------------------------------------------------------- */
.section--cta .section__lead strong {
  color: var(--color-text-light);
}

/* --------------------------------------------------------------------------
   16. FOOTER
   -------------------------------------------------------------------------- */
.footer {
  background-color: var(--color-navy);
  padding: 72px 0 48px;
  text-align: center;
}

.footer__inner {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 0;
}

.footer__brand {
  margin-bottom: 32px;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 12px;
}

.footer__logo {
  height: 40px;
  width: auto;
  display: block;
  opacity: 0.9;
}

.footer__name {
  font-family: var(--font-heading);
  font-size: 1.15rem;
  font-weight: 700;
  color: var(--color-text-light);
  letter-spacing: 0.06em;
  text-transform: uppercase;
  margin-bottom: 6px;
}

.footer__sub {
  font-size: 0.85rem;
  color: rgba(245, 245, 242, 0.55);
  font-weight: 400;
}

.footer__divider {
  width: 40px;
  height: 1px;
  background-color: var(--color-border-dark);
  margin: 0 auto 28px;
}

.footer__info {
  margin-bottom: 32px;
}

.footer__info p {
  font-size: 0.88rem;
  color: rgba(245, 245, 242, 0.65);
  margin-bottom: 6px;
}

.footer__info strong {
  color: rgba(245, 245, 242, 0.85);
}

.footer__links {
  display: flex;
  align-items: center;
  gap: 14px;
  margin-bottom: 32px;
}

.footer__links a {
  font-size: 0.82rem;
  color: rgba(245, 245, 242, 0.55);
  letter-spacing: 0.04em;
  transition: color var(--transition-base);
}

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

.footer__sep {
  color: var(--color-border-dark);
  font-size: 0.8rem;
}

.footer__copy {
  font-size: 0.78rem;
  color: rgba(245, 245, 242, 0.35);
  letter-spacing: 0.04em;
}

/* --------------------------------------------------------------------------
   17. FADE-IN ANIMATION
   -------------------------------------------------------------------------- */
.fade-in {
  opacity: 0;
  transform: translateY(16px);
  transition: opacity 0.5s ease, transform 0.5s ease;
}

.fade-in.visible {
  opacity: 1;
  transform: translateY(0);
}

/* --------------------------------------------------------------------------
   18. IMAGE BREAK
   -------------------------------------------------------------------------- */
.img-break {
  width: 100%;
  margin: 0;
  padding: 0;
  box-sizing: border-box;
  display: block;
}

.img-break img {
  display: block;
  width: 100%;
  height: auto;
  border-top: 3px solid var(--color-navy);
  border-bottom: 3px solid var(--color-navy);
}

/* --------------------------------------------------------------------------
   19. RESPONSIVE — TABLET (≤900px)
   -------------------------------------------------------------------------- */
@media (max-width: 900px) {
  :root {
    --section-padding: 72px;
  }

  .nav__links {
    display: none;
    position: absolute;
    top: 64px;
    left: 0;
    right: 0;
    background-color: var(--color-navy);
    flex-direction: column;
    gap: 0;
    border-top: 1px solid var(--color-border-dark);
    border-bottom: 1px solid var(--color-border-dark);
    padding: 16px 0;
  }

  .nav__links.open {
    display: flex;
  }

  .nav__links li {
    width: 100%;
    text-align: center;
  }

  .nav__links li a {
    display: block;
    padding: 12px 24px;
  }

  .nav__cta {
    margin: 8px auto;
    display: inline-block;
  }

  .nav__toggle {
    display: block;
  }

  .nav {
    position: relative;
  }

  /* Problem */
  .problem-grid {
    grid-template-columns: 1fr;
    max-width: 480px;
  }

  /* Cards */
  .card-row {
    grid-template-columns: 1fr;
    max-width: 480px;
  }

  /* How it works */
  .how-grid {
    grid-template-columns: 1fr;
    max-width: 560px;
  }

  .how-connector {
    padding-top: 0;
    transform: rotate(90deg);
    height: 40px;
  }

  /* Focus */
  .focus-grid {
    grid-template-columns: repeat(2, 1fr);
  }

  /* Metrics */
  .metrics-grid {
    grid-template-columns: repeat(2, 1fr);
  }

  /* Sectors */
  .sector-grid {
    grid-template-columns: repeat(3, 1fr);
  }
}

/* --------------------------------------------------------------------------
   20. RESPONSIVE — MOBILE (≤600px)
   -------------------------------------------------------------------------- */
@media (max-width: 600px) {
  :root {
    --section-padding: 56px;
    --container-padding: 20px;
  }

  .hero {
    padding: 72px 0 64px;
  }

  .hero__title {
    font-size: 2rem;
  }

  .hero__subtitle {
    font-size: 1.05rem;
  }

  .callout {
    padding: 28px 24px;
  }

  .exclusion-block {
    padding: 24px 20px;
  }

  /* Cards */
  .card-row {
    grid-template-columns: 1fr;
  }

  /* Focus */
  .focus-grid {
    grid-template-columns: 1fr 1fr;
  }

  /* Metrics */
  .metrics-grid {
    grid-template-columns: 1fr 1fr;
  }

  /* Sectors */
  .sector-grid {
    grid-template-columns: repeat(2, 1fr);
  }

  .footer__links {
    flex-direction: column;
    gap: 10px;
  }

  .footer__sep {
    display: none;
  }
}

@media (max-width: 400px) {
  .focus-grid {
    grid-template-columns: 1fr;
  }

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

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