/* ==========================================================================
   Design tokens
   ========================================================================== */

   :root {
    --ink: #0f0f0d;
    --paper: #f8f6f1;
    --warm: #eeebe2;
    --rule: rgba(15, 15, 13, 0.1);
    --teal: #0f6e56;
    --teal-bg: #e1f5ee;
    --teal-mid: #1d9e75;
    --mono: 'IBM Plex Mono', monospace;
    --serif: 'Instrument Serif', serif;
    --sans: 'IBM Plex Sans', sans-serif;
  }
  *,
  *::before,
  *::after {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
  }
  html {
    scroll-behavior: smooth;
  }
  body {
    background: var(--paper);
    color: var(--ink);
    font-family: var(--sans);
    font-size: 16px;
    line-height: 1.65;
    -webkit-font-smoothing: antialiased;
  }
  
  
  /* ==========================================================================
     Navigation
     ========================================================================== */
  
  nav {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    z-index: 100;
    background: var(--paper);
    border-bottom: 1px solid var(--rule);
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 0 2.5rem;
    height: 54px;
  }
  .nav-logo {
    font-family: var(--mono);
    font-size: 13px;
    font-weight: 500;
    letter-spacing: 0.04em;
    color: var(--ink);
  }
  .nav-logo em {
    color: var(--teal);
    font-style: normal;
  }
  .nav-links {
    display: flex;
    gap: 2rem;
    list-style: none;
  }
  .nav-links a {
    font-size: 13px;
    color: rgba(15, 15, 13, 0.45);
    text-decoration: none;
    letter-spacing: 0.02em;
    transition: color 0.15s;
  }
  .nav-links a:hover {
    color: var(--ink);
  }
  .nav-cta {
    font-family: var(--mono);
    font-size: 11px;
    font-weight: 500;
    letter-spacing: 0.08em;
    text-transform: uppercase;
    background: var(--teal);
    color: #fff;
    padding: 8px 16px;
    border-radius: 3px;
    text-decoration: none;
    transition: opacity 0.15s;
  }
  .nav-cta:hover {
    opacity: 0.85;
  }
  
  
  /* ==========================================================================
     Hero
     ========================================================================== */
  
  .hero {
    padding: 54px 0 0;
    min-height: 100vh;
    display: flex;
    align-items: center;
  }
  .hero-inner {
    max-width: 1120px;
    margin: 0 auto;
    padding: 5rem 2.5rem 4rem;
    display: grid;
    grid-template-columns: 1.1fr 0.9fr;
    gap: 5rem;
    align-items: center;
  }
  .hero-eyebrow {
    font-family: var(--mono);
    font-size: 11px;
    font-weight: 500;
    letter-spacing: 0.12em;
    text-transform: uppercase;
    color: var(--teal);
    margin-bottom: 1.25rem;
  }
  .hero h1 {
    font-family: var(--serif);
    font-size: clamp(2.6rem, 4.5vw, 4rem);
    line-height: 1.06;
    margin-bottom: 1.5rem;
  }
  .hero h1 i {
    font-style: italic;
    color: var(--teal);
  }
  .hero-lead {
    font-size: 17px;
    color: rgba(15, 15, 13, 0.55);
    line-height: 1.75;
    max-width: 480px;
    margin-bottom: 2.5rem;
  }
  .hero-actions {
    display: flex;
    gap: 1rem;
    align-items: center;
    flex-wrap: wrap;
  }
  .btn-dark {
    font-family: var(--mono);
    font-size: 12px;
    font-weight: 500;
    letter-spacing: 0.06em;
    text-transform: uppercase;
    background: var(--ink);
    color: #fff;
    padding: 12px 22px;
    border-radius: 3px;
    text-decoration: none;
    transition: background 0.15s;
  }
  .btn-dark:hover {
    background: var(--teal);
  }
  .btn-text {
    font-family: var(--mono);
    font-size: 12px;
    letter-spacing: 0.04em;
    color: rgba(15, 15, 13, 0.45);
    text-decoration: none;
    transition: color 0.15s;
  }
  .btn-text:hover {
    color: var(--ink);
  }
  
  
  /* --------------------------------------------------------------------------
     Hero: $BIRTH index panel
     -------------------------------------------------------------------------- */
  
  .index-panel {
    background: var(--ink);
    border-radius: 8px;
    padding: 2rem;
    color: #fff;
    font-family: var(--mono);
  }
  .ip-header {
    display: flex;
    justify-content: space-between;
    align-items: flex-start;
    margin-bottom: 1.75rem;
  }
  .ip-name {
    font-size: 10px;
    letter-spacing: 0.12em;
    text-transform: uppercase;
    color: rgba(255, 255, 255, 0.5);
    margin-bottom: 6px;
  }
  .ip-ticker {
    font-size: 16px;
    font-weight: 500;
    letter-spacing: 0.04em;
  }
  .ip-live {
    display: flex;
    align-items: center;
    gap: 6px;
    font-size: 10px;
    letter-spacing: 0.08em;
    text-transform: uppercase;
    color: rgba(255, 255, 255, 0.5);
  }
  .live-dot {
    width: 6px;
    height: 6px;
    border-radius: 50%;
    background: #1d9e75;
    animation: blink 2s infinite;
  }
  @keyframes blink {
    0%,
    100% {
      opacity: 1;
    }
    50% {
      opacity: 0.25;
    }
  }
  .ip-value {
    font-size: 3.5rem;
    font-weight: 300;
    letter-spacing: -0.03em;
    line-height: 1;
    margin-bottom: 4px;
  }
  .ip-delta {
    font-size: 12px;
    color: rgba(255, 255, 255, 0.5);
    margin-bottom: 2rem;
  }
  .ip-sparkline {
    display: block;
    margin-bottom: 1.5rem;
  }
  .ip-advantage {
    background: rgba(255, 255, 255, 0.05);
    border-radius: 4px;
    padding: 1.25rem;
    margin-bottom: 1.5rem;
  }
  .ip-advantage .adv-label {
    font-size: 10px;
    letter-spacing: 0.1em;
    text-transform: uppercase;
    color: rgba(255, 255, 255, 0.5);
    margin-bottom: 8px;
  }
  .ip-advantage .adv-row {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 6px 0;
    border-bottom: 1px solid rgba(255, 255, 255, 0.06);
  }
  .ip-advantage .adv-row:last-child {
    border-bottom: none;
  }
  .ip-advantage .adv-name {
    font-size: 12px;
    color: rgba(255, 255, 255, 0.5);
  }
  .ip-advantage .adv-val {
    font-size: 12px;
  }
  .adv-val.green {
    color: #1d9e75;
  }
  .adv-val.red {
    color: #e05c50;
  }
  .ip-sources {
    display: flex;
    gap: 8px;
    flex-wrap: wrap;
  }
  .ip-tag {
    font-size: 10px;
    letter-spacing: 0.06em;
    padding: 4px 10px;
    border-radius: 2px;
    background: rgba(255, 255, 255, 0.08);
    color: rgba(255, 255, 255, 0.5);
  }
  
  
  /* ==========================================================================
     Shared section layout
     ========================================================================== */
  
  section {
    padding: 5rem 2.5rem;
  }
  .container {
    max-width: 1120px;
    margin: 0 auto;
  }
  .sec-label {
    font-family: var(--mono);
    font-size: 10px;
    font-weight: 500;
    letter-spacing: 0.14em;
    text-transform: uppercase;
    color: rgba(15, 15, 13, 0.5);
    margin-bottom: 1rem;
    display: flex;
    align-items: center;
    gap: 10px;
  }
  .sec-label::after {
    content: '';
    flex: 0 0 24px;
    height: 1px;
    background: var(--rule);
  }
  h2 {
    font-family: var(--serif);
    font-size: clamp(2rem, 3vw, 2.8rem);
    line-height: 1.1;
    margin-bottom: 1.5rem;
  }
  
  
  /* ==========================================================================
     Methodology section ("Why this exists")
     ========================================================================== */
  
  .edge {
    background: var(--warm);
  }
  .edge-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 4rem;
    align-items: start;
  }
  .edge-intro {
    font-size: 17px;
    color: rgba(15, 15, 13, 0.55);
    line-height: 1.75;
    margin-bottom: 2.5rem;
  }
  .edge-intro--secondary {
    margin-top: 1.5rem;
  }
  .advantage-list {
    display: flex;
    flex-direction: column;
    gap: 1.25rem;
  }
  .advantage-item {
    display: grid;
    grid-template-columns: 32px 1fr;
    gap: 12px;
    align-items: start;
    padding-bottom: 1.25rem;
    border-bottom: 1px solid var(--rule);
  }
  .advantage-item:last-child {
    border-bottom: none;
    padding-bottom: 0;
  }
  .adv-num {
    font-family: var(--mono);
    font-size: 13px;
    color: var(--teal);
    font-weight: 500;
    padding-top: 2px;
  }
  .adv-body h4 {
    font-size: 14px;
    font-weight: 500;
    margin-bottom: 3px;
  }
  .adv-body p {
    font-size: 13px;
    color: rgba(15, 15, 13, 0.5);
    line-height: 1.6;
  }
  
  .tiers-intro {
    max-width: 580px;
    margin-bottom: 3rem;
  }
  .tiers-intro p {
    font-size: 17px;
    color: rgba(15, 15, 13, 0.55);
    line-height: 1.75;
  }
  
  /* ==========================================================================
     Pricing tiers
     ========================================================================== */
  
  .tier-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 1px;
    background: var(--rule);
    border: 1px solid var(--rule);
    border-radius: 6px;
    overflow: hidden;
    margin-bottom: 3.5rem;
  }
  .tier-card {
    background: var(--paper);
    padding: 2rem;
  }
  .tier-card.featured {
    background: var(--ink);
    color: #fff;
  }
  .tier-num {
    font-family: var(--mono);
    font-size: 10px;
    letter-spacing: 0.1em;
    text-transform: uppercase;
    color: rgba(15, 15, 13, 0.5);
    margin-bottom: 1rem;
  }
  .tier-card.featured .tier-num {
    color: rgba(255, 255, 255, 0.5);
  }
  .tier-name {
    font-family: var(--serif);
    font-size: 1.4rem;
    margin-bottom: 0.35rem;
  }
  .tier-price {
    font-family: var(--mono);
    font-size: 13px;
    color: var(--teal);
    margin-bottom: 1.25rem;
  }
  .tier-card.featured .tier-price {
    color: #5dcaa5;
  }
  .tier-desc {
    font-size: 14px;
    color: rgba(15, 15, 13, 0.5);
    line-height: 1.65;
    margin-bottom: 1.5rem;
  }
  .tier-card.featured .tier-desc {
    color: rgba(255, 255, 255, 0.45);
  }
  .tier-clients {
    font-family: var(--mono);
    font-size: 11px;
    color: rgba(15, 15, 13, 0.5);
    line-height: 1.8;
  }
  .tier-card.featured .tier-clients {
    color: rgba(255, 255, 255, 0.5);
  }
  .tier-tag {
    display: inline-block;
    font-family: var(--mono);
    font-size: 10px;
    letter-spacing: 0.06em;
    padding: 3px 8px;
    border-radius: 2px;
    background: rgba(255, 255, 255, 0.08);
    color: rgba(255, 255, 255, 0.45);
    margin-bottom: 1rem;
  }
  
  
  /* ==========================================================================
     Index Family section
     ========================================================================== */
  
  .sources {
    background: var(--ink);
    color: #fff;
  }
  .sources h2 {
    color: #fff;
  }
  .sources .sec-label {
    color: rgba(255, 255, 255, 0.5);
  }
  .sources .sec-label::after {
    background: rgba(255, 255, 255, 0.15);
  }
  .src-cols {
    display: grid;
    grid-template-columns: 1fr 1fr 1fr;
    gap: 1px;
    background: rgba(255, 255, 255, 0.08);
    border: 1px solid rgba(255, 255, 255, 0.08);
    border-radius: 6px;
    overflow: hidden;
    margin-top: 2.5rem;
  }
  .src-card {
    background: var(--ink);
    padding: 2rem;
  }
  .src-icon {
    font-family: var(--mono);
    font-size: 11px;
    letter-spacing: 0.1em;
    text-transform: uppercase;
    color: rgba(255, 255, 255, 0.5);
    margin-bottom: 1rem;
  }
  .src-card h3 {
    font-family: var(--serif);
    font-size: 1.3rem;
    color: #fff;
    margin-bottom: 0.5rem;
  }
  .src-card p {
    font-size: 14px;
    color: rgba(255, 255, 255, 0.4);
    line-height: 1.65;
  }
  .src-card .src-detail {
    font-family: var(--mono);
    font-size: 11px;
    color: rgba(255, 255, 255, 0.5);
    margin-top: 1rem;
    line-height: 1.7;
  }
  
  /* ==========================================================================
     Mission statement
     ========================================================================== */
  
  .mission {
    background: var(--ink);
    text-align: center;
    padding-top: 6rem;
    padding-bottom: 6rem;
    border-top: 1px solid rgba(255, 255, 255, 0.08);
  }
  .mission-container {
    max-width: 720px;
  }
  .mission-statement {
    color: #fff;
    font-size: clamp(1.9rem, 3vw, 2.5rem);
    font-weight: 400;
  }
  .mission-accent {
    color: var(--teal-mid);
    font-style: italic;
  }
  
  /* ==========================================================================
     Contact
     ========================================================================== */
  
  .contact {
    background: var(--teal);
    color: #fff;
    text-align: center;
  }
  .contact .sec-label {
    justify-content: center;
    color: rgba(255, 255, 255, 0.55);
  }
  .contact .sec-label::after {
    background: rgba(255, 255, 255, 0.2);
  }
  .contact h2 {
    color: #fff;
    max-width: 560px;
    margin: 0 auto 1.25rem;
  }
  .contact-sub {
    font-size: 17px;
    color: rgba(255, 255, 255, 0.55);
    max-width: 480px;
    margin: 0 auto 2.5rem;
    line-height: 1.75;
  }
  .contact-btns {
    display: flex;
    gap: 1rem;
    justify-content: center;
    flex-wrap: wrap;
  }
  .btn-white {
    font-family: var(--mono);
    font-size: 12px;
    font-weight: 500;
    letter-spacing: 0.06em;
    text-transform: uppercase;
    background: #fff;
    color: var(--teal);
    padding: 13px 24px;
    border-radius: 3px;
    text-decoration: none;
    transition: opacity 0.15s;
  }
  .btn-white:hover {
    opacity: 0.9;
  }
  .contact-legal {
    margin-top: 3rem;
    font-family: var(--mono);
    font-size: 11px;
    color: rgba(255, 255, 255, 0.55);
  }
  
  
  /* ==========================================================================
     Footer
     ========================================================================== */
  
  footer {
    background: var(--ink);
    color: rgba(255, 255, 255, 0.5);
    padding: 1.5rem 2.5rem;
    display: flex;
    justify-content: space-between;
    align-items: center;
    font-family: var(--mono);
    font-size: 11px;
    letter-spacing: 0.04em;
  }
  footer a {
    color: rgba(255, 255, 255, 0.5);
    text-decoration: none;
  }
  footer a:hover {
    color: rgba(255, 255, 255, 0.5);
  }
  .footer-links {
    display: flex;
    gap: 1.5rem;
  }
  
  
  /* ==========================================================================
     Scroll-reveal animation
     ========================================================================== */
  
  .fade-up {
    opacity: 0;
    transform: translateY(20px);
    transition:
      opacity 0.5s ease,
      transform 0.5s ease;
  }
  .fade-up.in {
    opacity: 1;
    transform: translateY(0);
  }
  
  
  /* ==========================================================================
     Responsive: mobile (<= 800px)
     ========================================================================== */
  
  @media (max-width: 800px) {
    .hero-inner,
    .edge-grid {
      grid-template-columns: 1fr;
      gap: 2.5rem;
    }
    .tier-grid,
    .src-cols {
      grid-template-columns: 1fr;
    }
    .src-card {
      padding: 1.5rem;
    }
    .nav-links {
      display: none;
    }
    footer {
      flex-direction: column;
      gap: 0.5rem;
      text-align: center;
      padding: 1.5rem 1.5rem;
    }
  }