/* ==========================================================================
   IDW-26 - signature.v1.css
   The SIGNATURE GRAPHICS - the living, built-in 2D/3D moments promoted from
   the homepage (SHT 01) so every sheet can carry one. Bespoke, not stock:
   real DOM that stays legible + indexable, with motion drawn from live
   geometry. Link this AFTER surveyed.v1.css, on pages that deploy a device,
   and load shared/diagrams.v1.js (the geometry/scroll drivers, all guarded).

     - THE BROKER : a living "exchange" schematic. Sources flow IN to a
       breathing engine and OUT to every target; connectors draw in on reveal,
       then carry endless actor-coloured travelling comets. JS writes each
       bezier 'd' from live node geometry, so lines always meet the cards.

   (Flip-board and other devices are added here as they are deployed.)
   ========================================================================== */

/* ==========================================================================
   THE BROKER - living exchange schematic
   ========================================================================== */
/* the host .sheet-section must opt out of content-visibility:auto too, else
   the broker is laid out from a skipped box and depends on ResizeObserver to
   recover its connector geometry on first scroll-in (add .bk-section to it). */
.bk-section{content-visibility:visible}
.bk-net{position:relative;margin:40px auto 0;max-width:1040px;content-visibility:visible}
.bk-wires{position:absolute;inset:0;width:100%;height:100%;pointer-events:none;z-index:0;overflow:visible}

.bk-grid{
  position:relative;z-index:1;
  display:grid;
  grid-template-columns:minmax(0,1fr) minmax(200px,1.05fr) minmax(0,1fr);
  gap:clamp(20px,4vw,64px);
  align-items:center;
}
.bk-col{display:flex;flex-direction:column}
.bk-col-eng{align-items:center}
.bk-h{font-family:var(--font-mono);font-size:10px;font-weight:700;letter-spacing:1.3px;text-transform:uppercase;color:var(--ink-3);margin-bottom:14px}
.bk-h-center{text-align:center}

/* node cards: flat poster surfaces, actor colour as a left datum bar */
.bk-node{
  position:relative;padding:13px 15px;
  border:1px solid var(--hairline);border-left:3px solid var(--rule,var(--hairline-strong));
  border-radius:10px;background:var(--surface);
  transition:transform .22s var(--ease-out-soft), border-color .22s var(--ease-out-soft);
}
.bk-col-src .bk-node + .bk-node,
.bk-col-tgt .bk-node + .bk-node{margin-top:14px}
.bk-node b{display:block;font-size:13px;font-weight:700;color:var(--ink-1);line-height:1.25}
.bk-node span{display:block;margin-top:3px;font-family:var(--font-mono);font-size:10.5px;color:var(--ink-3);letter-spacing:.03em}
/* the dead nodes get a lift + an actor-colour glow on hover */
.bk-node::after{content:'';position:absolute;inset:-1px;border-radius:inherit;pointer-events:none;opacity:0;
  box-shadow:0 0 0 1px color-mix(in srgb,var(--rule) 45%,transparent), 0 14px 40px -16px color-mix(in srgb,var(--rule) 55%,transparent);
  transition:opacity .22s var(--ease-out-soft)}
@media (hover:hover) and (pointer:fine){
  .bk-node:hover{transform:translateY(-2px);border-color:color-mix(in srgb,var(--rule) 35%,var(--hairline-strong))}
  .bk-node:hover::after{opacity:1}
}

/* the engine - the hero node: slightly larger, lifted, breathing */
.bk-engine{
  width:100%;padding:24px 22px;
  border:1px solid var(--hairline-strong);border-left:3px solid var(--c-idw);border-radius:13px;
  background:linear-gradient(180deg,rgba(255,255,255,.025),transparent 32%),var(--surface);
  box-shadow:inset 0 1px 0 rgba(255,255,255,.05), 0 22px 52px -28px rgba(0,0,0,.85);
  overflow:hidden;isolation:isolate;
}
.bk-core-t{position:relative;z-index:2;font-family:var(--font-mono);font-size:12px;font-weight:700;letter-spacing:1.2px;text-transform:uppercase;color:var(--ink-1)}
.bk-core-d{position:relative;z-index:2;margin-top:7px;font-family:var(--font-mono);font-size:10.5px;color:var(--ink-3);letter-spacing:.06em;text-transform:uppercase;line-height:1.5}
/* breathing - opacity only (never box-shadow transitions): a soft wash that
   breathes + a thin ring that pulses a beat behind it. */
.bk-engine-glow{position:absolute;inset:-1px;z-index:0;border-radius:inherit;background:radial-gradient(120% 90% at 50% 50%, rgba(37,99,235,.30), rgba(37,99,235,0) 70%);opacity:.45;will-change:opacity}
.bk-engine-ring{position:absolute;inset:0;z-index:1;border-radius:inherit;box-shadow:inset 0 0 0 1px rgba(96,165,250,.35);opacity:0}
html.js .bk-net.in .bk-engine-glow{animation:bk-breathe 4.6s var(--ease-monument) infinite}
html.js .bk-net.in .bk-engine-ring{animation:bk-ring 4.6s var(--ease-monument) infinite}
@keyframes bk-breathe{0%,100%{opacity:.40}50%{opacity:.80}}
@keyframes bk-ring{0%,100%{opacity:0}55%{opacity:.9}}

/* connectors: the drawn rail (dim, draws in on .in) + a travelling comet.
   pathLength="1" => dasharray/dashoffset use 0..1. */
.bk-line{
  fill:none;stroke:var(--c,var(--hairline-strong));stroke-width:var(--stroke-w,1.25px);
  stroke-linecap:round;vector-effect:non-scaling-stroke;
  opacity:.42;stroke-dasharray:1;stroke-dashoffset:1;
}
html.js .bk-net.in .bk-line{stroke-dashoffset:0;transition:stroke-dashoffset .9s var(--ease-draw);transition-delay:calc(.18s + var(--i,0) * .07s)}
html:not(.js) .bk-line{stroke-dashoffset:0}
.bk-comet{
  fill:none;stroke:var(--c,var(--sky));stroke-width:calc(var(--stroke-w,1.25px) + 1px);
  stroke-linecap:round;vector-effect:non-scaling-stroke;
  stroke-dasharray:.05 .95;stroke-dashoffset:1;opacity:0;
  filter:drop-shadow(0 0 3px var(--c,var(--sky)));
}
html.js .bk-net.in .bk-comet{opacity:.95;animation:bk-comet-run 2.8s linear infinite;animation-delay:calc(1.7s + var(--d,0s))}
@keyframes bk-comet-run{from{stroke-dashoffset:1}to{stroke-dashoffset:0}}

/* reduced motion / save-data: rails fully drawn, no comets, engine static */
html.no-motion .bk-line{stroke-dashoffset:0 !important;transition:none !important}
html.no-motion .bk-comet{display:none !important}
html.no-motion .bk-engine-glow{opacity:.5 !important;animation:none !important}
html.no-motion .bk-engine-ring{opacity:0 !important;animation:none !important}
html.no-motion .bk-node,html.no-motion .bk-node::after{transition:none}
html.no-motion .bk-node::after{display:none}

/* mobile: stack vertically, flow rotates top -> bottom; sources/targets become
   a 2-col chip grid so the column isn't a long ladder. */
@media (max-width:880px){
  .bk-net{margin-top:32px}
  .bk-grid{grid-template-columns:1fr;gap:30px}
  .bk-col-src{order:1}.bk-col-eng{order:2}.bk-col-tgt{order:3}
  .bk-h{text-align:center}
  .bk-col-src,.bk-col-tgt{display:grid;grid-template-columns:1fr 1fr;gap:12px}
  .bk-col-src .bk-h,.bk-col-tgt .bk-h{grid-column:1/-1;margin-bottom:4px}
  .bk-col-src .bk-node + .bk-node,
  .bk-col-tgt .bk-node + .bk-node{margin-top:0}
  .bk-engine{max-width:420px;margin:0 auto}
  .bk-line{opacity:.3}
}
@media (max-width:460px){
  .bk-col-src,.bk-col-tgt{grid-template-columns:1fr}
}

/* ==========================================================================
   THE FLIP-BOARD - a scroll-pinned 3D journey. .jy-pin reserves the scroll
   travel (its height) so CLS = 0; .jy-stage is sticky-pinned and centred;
   left = a datum rail (travelling pulse + lit station dots), right = the
   flip-board where each step card flips in top-hinged as you scroll. The
   driver (diagrams.v1.js) maps scroll progress to discrete flip states.

   Per deployment:
     <section class="sheet-section jy-section"> ... wrap the device ...
     <div class="jy-pin" style="--steps:6">      (--steps = number of cards)
       <div class="jy-stage"> <div class="jy-intro">...</div>
         <div class="jy-flip"> <div class="jy-bar">...N dots...</div>
           <div class="jy-board"><ol class="jy-slot"> N x <li class="jy-card">
   Set the right-column list label with style="--jy-sys-label:'Form factors'".
   ========================================================================== */
.jy-section{content-visibility:visible}   /* the tall pin must not be skipped */
.jy-pin{
  --steps:6;
  --travel:58vh;                 /* scroll distance per step (tune to taste) */
  position:relative;
  margin-top:8px;
  height:calc(var(--travel) * var(--steps) + 40vh);
}
.jy-stage{
  position:sticky;
  top:max(84px, calc(50vh - 236px));   /* centre the intro+board block, clear the nav */
  display:flex;flex-direction:column;justify-content:center;
  gap:26px;
  height:472px;
}
.jy-intro{max-width:936px;width:100%;margin:0 auto}
.jy-intro .h2-sheet{margin-top:10px}
.jy-intro .lede{margin-top:12px}
.jy-flip{
  display:grid;
  grid-template-columns:46px minmax(0,860px);
  justify-content:center;
  gap:30px;
  align-items:stretch;
  height:264px;
}

/* --- the datum rail (track + travelling pulse + station dots) --- */
.jy-bar{position:relative;width:46px}
.jy-bar-track{position:absolute;left:1px;top:8px;bottom:8px;width:2px;background:var(--datum);opacity:.5}
.jy-bar-fill{
  position:absolute;left:0;top:0;width:2px;height:100%;
  transform-origin:top;transform:scaleY(0);
  background:linear-gradient(180deg,var(--blue),var(--amber));
  box-shadow:0 0 10px rgba(96,165,250,.45);
}
.jy-bar-orb{
  position:absolute;left:1px;top:0;margin-left:-6px;margin-top:-6px;
  width:12px;height:12px;border-radius:50%;pointer-events:none;opacity:0;color:#60a5fa;
  background:
    radial-gradient(circle, var(--ink-1) 0 2.2px, rgba(0,0,0,0) 3px),
    radial-gradient(circle, currentColor 0 1.8px, rgba(0,0,0,0) 7px);
  box-shadow:0 0 12px currentColor;
}
.jy-dot{
  position:absolute;left:1px;margin-left:-5px;margin-top:-5px;
  width:10px;height:10px;border-radius:50%;
  top:calc(8px + (100% - 16px) * var(--f));
  background:#232a35;border:1px solid #3b4250;
  box-shadow:0 0 0 3px var(--bg);
  transition:background .3s var(--ease-out-soft),border-color .3s var(--ease-out-soft),box-shadow .3s var(--ease-out-soft),transform .3s var(--ease-out-soft);
}
.jy-dot.is-lit{background:var(--rule);border-color:var(--rule);box-shadow:0 0 0 3px var(--bg),0 0 12px var(--rule)}
.jy-dot.is-here{transform:scale(1.35)}

/* --- the flip-board: a perspective stage holding stacked card faces --- */
.jy-board{position:relative;perspective:1200px;perspective-origin:50% 32%}
.jy-slot{position:relative;height:100%;transform-style:preserve-3d;margin:0;padding:0;list-style:none}
.jy-card{
  position:absolute;inset:0;
  transform-origin:top center;                       /* TOP hinge -> flips down */
  backface-visibility:hidden;-webkit-backface-visibility:hidden;
  border:1px solid var(--hairline-strong);border-left:3px solid var(--rule);border-radius:14px;
  background:linear-gradient(180deg,rgba(255,255,255,.045),transparent 28%),#13171f;
  padding:28px 34px;overflow:hidden;
  box-shadow:inset 0 1px 0 rgba(255,255,255,.06), 0 30px 70px -32px rgba(0,0,0,.85);
  display:grid;grid-template-columns:1.55fr minmax(148px,.82fr);column-gap:38px;align-content:center;
}
.jy-card h3{
  position:relative;margin:0 0 12px;
  font:560 clamp(22px,2.4vw,31px)/1.12 var(--font-display);
  letter-spacing:-.015em;color:var(--ink-1);
}
.jy-card p{position:relative;max-width:44ch;margin:0;color:var(--ink-2);font-size:15.5px;line-height:1.55}
.jy-step{display:block;font-size:10px;font-weight:800;letter-spacing:1.3px;text-transform:uppercase;color:var(--rule);margin-bottom:9px;font-variant-numeric:tabular-nums;position:relative;font-family:var(--font-mono)}
.jy-card .jy-step{grid-column:1;grid-row:1}
.jy-card h3{grid-column:1;grid-row:2}
.jy-card p{grid-column:1;grid-row:3}
.jy-systems{
  grid-column:2;grid-row:1 / 4;align-self:center;
  display:flex;flex-direction:column;flex-wrap:nowrap;align-items:stretch;gap:9px;
  border-left:1px solid var(--hairline);padding-left:26px;margin:0;
}
.jy-systems::before{
  content:var(--jy-sys-label,"Connected systems");display:block;margin-bottom:3px;
  /* --ink-3 not --ink-4: at 9px this label must clear WCAG 1.4.3 (4.5:1) */
  font-family:var(--font-mono);font-size:9px;font-weight:700;letter-spacing:1.4px;text-transform:uppercase;color:var(--ink-3);
}
.jy-systems span{
  font-size:12px;font-weight:500;color:var(--ink-2);
  display:flex;align-items:center;gap:9px;
}
.jy-systems span::before{content:"";width:5px;height:5px;border-radius:50%;background:var(--rule);flex:none;box-shadow:0 0 6px var(--rule)}

/* flip states (html.js-gated so JS-off shows a clean static stack). Only the
   active card is visible; past flips down+away, next/future sit cocked above. */
html.js .jy-card{transform:rotateX(-92deg);opacity:0;will-change:transform,opacity;
  transition:transform var(--t-flip) var(--ease-flip), opacity 240ms linear, box-shadow var(--t-flip) var(--ease-monument)}
html.js .jy-card.is-active{transform:rotateX(0deg);opacity:1;z-index:3;
  transition-delay:90ms,0ms,90ms;
  box-shadow:0 44px 84px -34px rgba(0,0,0,.88), 0 3px 12px -3px rgba(0,0,0,.55)}
html.js .jy-card.is-past{transform:rotateX(80deg);opacity:0;z-index:1;
  transition:transform 300ms var(--ease-snap), opacity 170ms linear, box-shadow 300ms linear}
html.js .jy-card.is-next{transform:rotateX(-92deg);opacity:0;z-index:2}
html.js .jy-card.is-future{transform:rotateX(-92deg);opacity:0;z-index:0}
html.js .jy-pin:not(.jy-armed) .jy-card:first-child{transform:rotateX(0deg);opacity:1}

@media (max-width:680px){
  .jy-stage{gap:18px;height:400px;top:max(76px, calc(50vh - 200px))}
  .jy-flip{grid-template-columns:30px minmax(0,1fr);gap:18px;height:auto;min-height:400px}
  .jy-card{padding:24px 22px;grid-template-columns:1fr;column-gap:0;align-content:start}
  .jy-card .jy-step{grid-row:auto}
  .jy-card h3{grid-row:auto}
  .jy-card p{grid-row:auto;max-width:none;font-size:15px}
  .jy-card .jy-systems{grid-column:1;grid-row:auto;align-self:auto;border-left:0;padding-left:0;margin-top:16px;flex-direction:row;flex-wrap:wrap;gap:6px}
  .jy-card .jy-systems::before{flex-basis:100%;margin-bottom:6px}
  .jy-card .jy-systems span{border:1px solid var(--hairline);border-radius:6px;padding:4px 9px;text-transform:uppercase;font-size:10px;font-weight:600;color:var(--ink-3)}
  .jy-card .jy-systems span::before{display:none}
}

/* reduced motion / JS-off: a clean numbered static stack; each card keeps its
   --rule left border so the actor colour still reads. */
html.no-motion .jy-pin,html:not(.js) .jy-pin{height:auto;margin-top:8px}
html.no-motion .jy-stage,html:not(.js) .jy-stage{position:static;display:block;height:auto}
/* the bar is hidden in the static stack, so the board must NOT stay in the
   46px|860px grid (it would auto-place into the 46px rail track and crush) */
html.no-motion .jy-flip,html:not(.js) .jy-flip{display:block;height:auto}
html.no-motion .jy-board,html:not(.js) .jy-board{perspective:none}
html.no-motion .jy-slot,html:not(.js) .jy-slot{height:auto}
html.no-motion .jy-card{position:relative;inset:auto;transform:none !important;opacity:1 !important;transition:none;box-shadow:none;margin-bottom:14px;will-change:auto}
html:not(.js) .jy-card{position:relative;inset:auto;margin-bottom:14px;box-shadow:none}
html.no-motion .jy-bar,html:not(.js) .jy-bar{display:none}

/* short viewports (landscape phones / tiny windows): the 472px pinned stage
   would exceed the height and clip the active card below the fold. Fall back
   to a flat static stack (the JS driver's flip transforms are overridden). */
@media (max-height:640px){
  .jy-pin{height:auto !important;margin-top:8px}
  .jy-stage{position:static !important;display:block;height:auto}
  .jy-flip{display:block;height:auto}
  .jy-board{perspective:none}
  .jy-slot{height:auto}
  .jy-card{position:relative;inset:auto;transform:none !important;opacity:1 !important;box-shadow:none;margin-bottom:14px}
  .jy-bar{display:none}
}