/* Desktop chapter navigation rail — a bare text-and-dot index, no card shell. */
@media (min-width: 981px) {
  .chapter-nav {
    position: fixed !important;
    top: 50% !important;
    right: 28px !important;
    left: auto !important;
    bottom: auto !important;
    transform: translateY(-50%) !important;
    z-index: 80 !important;
    display: flex !important;
    flex-direction: column !important;
    align-items: flex-end !important;
    gap: 7px !important;
    width: auto !important;
    min-height: 0 !important;
    padding: 0 !important;
    overflow: visible !important;
    border: 0 !important;
    border-radius: 0 !important;
    background: transparent !important;
    box-shadow: none !important;
    backdrop-filter: none !important;
    -webkit-backdrop-filter: none !important;
  }
  .chapter-nav a {
    display: grid !important;
    grid-template-columns: minmax(0, 1fr) 30px !important;
    align-items: center !important;
    gap: 11px !important;
    width: 126px !important;
    min-height: 30px !important;
    padding: 0 !important;
    border: 0 !important;
    border-radius: 0 !important;
    background: transparent !important;
    color: #a4aaa6 !important;
    font-size: 10px !important;
    letter-spacing: .055em !important;
    text-transform: uppercase !important;
    text-decoration: none !important;
    white-space: nowrap !important;
    opacity: .62 !important;
    transform: none !important;
    transition: color .32s ease, opacity .32s ease, transform .38s cubic-bezier(.2,.9,.2,1.25), font-size .32s ease !important;
  }
  .chapter-nav a:hover {
    color: #59615b !important;
    opacity: .95 !important;
    background: transparent !important;
    transform: translateX(-2px) !important;
  }
  .chapter-nav a b {
    grid-column: 1 !important;
    grid-row: 1 !important;
    justify-self: end !important;
    font-weight: 720 !important;
  }
  .chapter-nav a span {
    grid-column: 2 !important;
    grid-row: 1 !important;
    justify-self: center !important;
    display: block !important;
    width: 3px !important;
    height: 3px !important;
    padding: 0 !important;
    border-radius: 50% !important;
    background: #a7adaa !important;
    color: transparent !important;
    font-size: 0 !important;
    line-height: 0 !important;
    opacity: 1 !important;
    box-shadow: none !important;
    transform: scale(1) !important;
    transform-origin: center !important;
    transition: width .42s cubic-bezier(.2,.9,.2,1.35), height .42s cubic-bezier(.2,.9,.2,1.35), background .3s ease, box-shadow .35s ease, transform .35s ease !important;
  }
  .chapter-nav a.rail-near-2 {
    opacity: .72 !important;
    font-size: 10.5px !important;
  }
  .chapter-nav a.rail-near-2 span {
    width: 7px !important;
    height: 7px !important;
  }
  .chapter-nav a.rail-near-1 {
    color: #7d8580 !important;
    opacity: .86 !important;
    font-size: 12.5px !important;
    transform: translateX(-2px) !important;
  }
  .chapter-nav a.rail-near-1 span {
    width: 14px !important;
    height: 14px !important;
    background: #8f9792 !important;
  }
  .chapter-nav a.is-current {
    color: #0b6b3b !important;
    opacity: 1 !important;
    font-size: 14px !important;
    background: transparent !important;
    transform: translateX(-6px) !important;
  }
  .chapter-nav a.is-current b {
    font-weight: 820 !important;
  }
  .chapter-nav a.is-current span {
    width: 26px !important;
    height: 26px !important;
    background: #0b6b3b !important;
    box-shadow: 0 0 0 7px rgba(11, 107, 59, .13) !important;
    animation: rail-dot-arrive .48s cubic-bezier(.2,.95,.25,1.35), rail-dot-breathe 1.9s ease-in-out .48s infinite !important;
  }
  @keyframes rail-dot-arrive {
    0% { transform: scale(.35); }
    72% { transform: scale(1.14); }
    100% { transform: scale(1); }
  }
  @keyframes rail-dot-breathe {
    0%, 100% { transform: scale(1); box-shadow: 0 0 0 7px rgba(11, 107, 59, .13); }
    50% { transform: scale(1.09); box-shadow: 0 0 0 11px rgba(11, 107, 59, .055); }
  }
  @media (prefers-reduced-motion: reduce) {
    .chapter-nav a,
    .chapter-nav a span {
      transition-duration: .01ms !important;
    }
    .chapter-nav a.is-current span {
      animation: none !important;
    }
  }
  .story-hero {
    min-height: calc(100vh - var(--header-h)) !important;
  }
  .chapter {
    scroll-margin-top: calc(var(--header-h) + 12px) !important;
  }
}

/* Final rail layer: this file is intentionally last so legacy rail rules cannot
   cover the lesson content or reintroduce the oversized active dot. */
@media (min-width:981px){
  .story-hero,.chapter,.behind-scenes,.final-cta,.learn-footer{
    width:min(var(--max),calc(100% - 260px)) !important;
    margin-left:clamp(28px,5vw,76px) !important;
    margin-right:auto !important;
  }

  .chapter-nav{
    top:calc(var(--header-h) + (100vh - var(--header-h)) / 2) !important;
    right:clamp(18px,3vw,44px) !important;
    width:144px !important;
    gap:2px !important;
    padding:15px 0 15px 18px !important;
    transform:translateY(-50%) !important;
    border-left:1px solid rgba(15,21,17,.16) !important;
  }

  .chapter-nav::before{
    content:"LEARNING PATH / 08";
    display:block;
    margin:0 0 11px;
    color:rgba(15,21,17,.42);
    font-size:8px;
    font-weight:900;
    letter-spacing:.14em;
    line-height:1.2;
  }

  .chapter-nav a{
    position:relative !important;
    display:grid !important;
    grid-template-columns:24px minmax(0,1fr) !important;
    gap:8px !important;
    width:126px !important;
    min-height:34px !important;
    padding:0 10px 0 0 !important;
    border:0 !important;
    border-radius:0 !important;
    color:rgba(15,21,17,.46) !important;
    font-size:11px !important;
    letter-spacing:.015em !important;
    text-transform:none !important;
    opacity:1 !important;
    transform:none !important;
    transition:color .2s ease,background .2s ease,padding-left .2s ease !important;
  }

  .chapter-nav a::before{
    content:"";
    position:absolute;
    left:-19px;
    top:0;
    bottom:0;
    width:1px;
    background:transparent;
    transition:background .2s ease;
  }

  .chapter-nav a:hover{
    color:var(--ink) !important;
    background:transparent !important;
    transform:none !important;
  }

  .chapter-nav a b{
    grid-column:2 !important;
    grid-row:1 !important;
    justify-self:start !important;
    align-self:center !important;
    font-weight:720 !important;
  }

  .chapter-nav a span{
    grid-column:1 !important;
    grid-row:1 !important;
    justify-self:start !important;
    align-self:center !important;
    width:auto !important;
    height:auto !important;
    border-radius:0 !important;
    background:none !important;
    color:rgba(15,21,17,.34) !important;
    font-size:9px !important;
    line-height:1 !important;
    font-variant-numeric:tabular-nums !important;
    opacity:1 !important;
    box-shadow:none !important;
    transform:none !important;
    transition:color .2s ease,font-weight .2s ease !important;
  }

  .chapter-nav a.rail-near-2,
  .chapter-nav a.rail-near-1,
  .chapter-nav a.is-current{
    font-size:11px !important;
    opacity:1 !important;
    transform:none !important;
  }

  .chapter-nav a.rail-near-1{color:rgba(15,21,17,.72) !important}
  .chapter-nav a.rail-near-1 span,
  .chapter-nav a.rail-near-2 span{width:auto !important;height:auto !important;background:none !important}

  .chapter-nav a.is-current{
    color:var(--ink) !important;
    padding-left:8px !important;
    background:var(--lime) !important;
    font-size:12px !important;
  }

  .chapter-nav a.is-current::before{background:var(--green)}
  .chapter-nav a.is-current b{font-weight:850 !important}
  .chapter-nav a.is-current span{
    width:auto !important;
    height:auto !important;
    background:none !important;
    color:var(--green) !important;
    box-shadow:none !important;
    font-weight:900 !important;
    animation:none !important;
  }

  .story-hero{min-height:calc(100vh - var(--header-h) - 32px) !important;padding-top:62px !important}
  .chapter{scroll-margin-top:calc(var(--header-h) + 24px) !important}
}