/* ==================================================================
   THE T LAB - portal pillar
   ================================================================== */

:root {
  --bg:        #000206;   /* near-black so the accents read as light sources */
  --bg-2:      #03060f;
  --panel:     #04070f;   /* solid fill inside portal frames */
  --ink:       #ffffff;
  --ink-dim:   #8fa0bd;
  --ink-faint: #4a5877;
  --accent:    #00e5ff;
  --line:      rgba(110, 160, 255, 0.10);

  --portal-size: clamp(170px, 24vmin, 300px);
  --cart-w: calc(var(--portal-size) * 0.80);   /* cartridge width  */
  --cart-h: var(--portal-size);                /* cartridge height */
  --cart-d: calc(var(--portal-size) * 0.15);   /* cartridge depth  */
  --ease-out: cubic-bezier(0.16, 1, 0.3, 1);
}

* { box-sizing: border-box; margin: 0; padding: 0; }

html, body {
  height: 100%;
  overflow: hidden;
  background: var(--bg);
  color: var(--ink);
  font-family: 'Space Grotesk', system-ui, sans-serif;
  -webkit-font-smoothing: antialiased;
  overscroll-behavior: none;
}

body { position: relative; }

/* --- ambient background ------------------------------------------ */

.bg-grid {
  position: fixed; inset: -20%;
  background-image:
    linear-gradient(var(--line) 1px, transparent 1px),
    linear-gradient(90deg, var(--line) 1px, transparent 1px);
  background-size: 64px 64px;
  transform: perspective(600px) rotateX(62deg) translateZ(-120px);
  transform-origin: 50% 100%;
  opacity: 0.32;
  mask-image: radial-gradient(ellipse 70% 60% at 50% 60%, #000 0%, transparent 75%);
  -webkit-mask-image: radial-gradient(ellipse 70% 60% at 50% 60%, #000 0%, transparent 75%);
  pointer-events: none;
  animation: grid-drift 24s linear infinite;
}
@keyframes grid-drift { to { background-position: 0 64px, 64px 0; } }

.bg-glow {
  position: fixed; inset: 0;
  background:
    radial-gradient(ellipse 34% 42% at 50% 48%, color-mix(in srgb, var(--accent) 16%, transparent) 0%, transparent 70%),
    radial-gradient(ellipse 70% 40% at 50% 112%, color-mix(in srgb, var(--accent) 10%, transparent) 0%, transparent 70%),
    linear-gradient(180deg, var(--bg) 0%, var(--bg-2) 55%, var(--bg) 100%);
  pointer-events: none;
  transition: background 700ms linear;
}

#starfield { position: fixed; inset: 0; width: 100%; height: 100%; pointer-events: none; opacity: 0.75; }

/* atmospheric depth: the tower dissolves into haze top and bottom.
   Done in screen space so nothing in the 3D scene needs an opacity
   (which would flatten preserve-3d children). */
.fog {
  position: fixed; inset: 0; z-index: 20; pointer-events: none;
  background:
    linear-gradient(180deg, var(--bg) 0%, color-mix(in srgb, var(--bg) 82%, transparent) 11%, transparent 27%),
    linear-gradient(0deg,   var(--bg) 0%, color-mix(in srgb, var(--bg) 82%, transparent) 11%, transparent 27%);
}

.vignette {
  position: fixed; inset: 0; pointer-events: none;
  background: radial-gradient(ellipse 78% 78% at 50% 50%, transparent 38%, #000 100%);
}

.scanlines {
  position: fixed; inset: 0; pointer-events: none; opacity: 0.16;
  background: repeating-linear-gradient(180deg, rgba(255,255,255,0.035) 0 1px, transparent 1px 3px);
  mix-blend-mode: overlay;
}

/* --- HUD ---------------------------------------------------------- */

.hud {
  position: fixed; left: 0; right: 0; z-index: 40;
  display: flex; align-items: center; justify-content: space-between;
  padding: clamp(16px, 3vw, 32px) clamp(18px, 4vw, 48px);
  font-family: 'JetBrains Mono', ui-monospace, monospace;
  font-size: 11px; letter-spacing: 0.18em; text-transform: uppercase;
  color: var(--ink-dim);
  pointer-events: none;
}
.hud-top { top: 0; }
.hud-bottom { bottom: 0; justify-content: center; }

.brand { display: flex; align-items: center; gap: 12px; color: var(--ink); }
.brand-mark {
  width: 10px; height: 10px; border: 1px solid var(--accent);
  box-shadow: 0 0 12px var(--accent), inset 0 0 6px var(--accent);
  transform: rotate(45deg);
  animation: mark-pulse 3.2s ease-in-out infinite;
}
@keyframes mark-pulse { 0%, 100% { opacity: 1 } 50% { opacity: 0.35 } }
.brand-text { font-weight: 500; letter-spacing: 0.34em; font-size: 12px; }

.hud-meta { display: flex; align-items: center; gap: 14px; }
#counter { color: var(--accent); font-variant-numeric: tabular-nums; transition: color 500ms linear; }
.hud-divider { width: 40px; height: 1px; background: var(--line); }

.hint { opacity: 0.6; font-size: 10px; }
.hint-key { color: var(--accent); }
.hint-sep { margin: 0 10px; opacity: 0.4; }

/* --- stage / pillar ----------------------------------------------- */

.stage {
  position: fixed; inset: 0;
  display: grid; place-items: center;
  perspective: 1400px;
  perspective-origin: 50% 50%;
  z-index: 10;
}

.pillar-wrap {
  position: relative;
  width: 100%; height: 100%;
  transform-style: preserve-3d;
  display: grid; place-items: center;
  transform: translateX(var(--pillar-shift, 0px));
}

.pillar { position: absolute; top: 50%; left: 50%; transform-style: preserve-3d; will-change: transform; }
.helix  { position: absolute; transform-style: preserve-3d; }

/* central glowing spine of the pillar */
.spine {
  position: absolute; top: 50%; left: 50%;
  width: 6px; height: 220vh;
  transform: translate(-50%, -50%) translateZ(-1px);
  pointer-events: none;
}
.spine-core {
  position: absolute; inset: 0;
  background: linear-gradient(180deg, transparent, var(--accent) 18%, #fff 50%, var(--accent) 82%, transparent);
  opacity: 0.5;
  box-shadow: 0 0 24px 3px color-mix(in srgb, var(--accent) 55%, transparent);
  transition: box-shadow 600ms linear, background 600ms linear;
}
.spine-pulse {
  position: absolute; left: -3px; width: 8px; height: 22vh;
  background: linear-gradient(180deg, transparent, #fff, transparent);
  filter: blur(4px); opacity: 0.55;
  animation: spine-travel 4.5s cubic-bezier(0.5, 0, 0.5, 1) infinite;
}
@keyframes spine-travel { 0% { top: -25vh } 100% { top: 100% } }

.floor-ring {
  position: absolute; bottom: 6vh; left: 50%;
  width: 62vmin; height: 18vmin;
  transform: translateX(-50%);
  border-radius: 50%;
  background: radial-gradient(ellipse at center, color-mix(in srgb, var(--accent) 22%, transparent) 0%, transparent 68%);
  filter: blur(14px);
  pointer-events: none;
  transition: background 600ms linear;
}

/* --- portals ------------------------------------------------------ */

.portal {
  position: absolute;
  top: 50%; left: 50%;
  width: var(--cart-w); height: var(--cart-h);
  margin: calc(var(--cart-h) / -2) 0 0 calc(var(--cart-w) / -2);
  transform-style: preserve-3d;
  cursor: pointer;
  will-change: transform, opacity;
  -webkit-tap-highlight-color: transparent;
}

.portal-inner {
  position: absolute; inset: 0;
  display: grid; place-items: center;
  transform-style: preserve-3d;      /* without this the barrel flattens */
  transition: transform 500ms var(--ease-out);
}
.portal:hover .portal-inner { transform: scale(1.07); }

/* --- the cartridge -------------------------------------------------
   A real six-sided box. Thickness is inherent to the form, so it reads
   as an object from every angle without any tricks.                  */

.cart { position: absolute; inset: 0; transform-style: preserve-3d; }

.cart-face, .cart-back, .cart-side {
  position: absolute;
  background: linear-gradient(158deg, #ffffff, #ccd4e2);
  border: 1px solid rgba(18, 26, 44, 0.28);
}

/* front */
.cart-face {
  inset: 0;
  transform: translateZ(calc(var(--cart-d) / 2));
  border-color: color-mix(in srgb, var(--pc) 55%, #7c8598);
  box-shadow:
    inset 0 -22px 30px rgba(120, 140, 175, 0.30),
    0 0 46px color-mix(in srgb, var(--pc) 42%, transparent),
    0 16px 44px rgba(0, 0, 0, 0.65);
  display: flex; flex-direction: column;
  padding: 12% 11%;
  overflow: hidden;
}
.cart-back { inset: 0; transform: translateZ(calc(var(--cart-d) / -2)) rotateY(180deg); filter: brightness(0.45); }

/* four walls */
.cart-side { filter: brightness(0.62); }
.cart-side.l, .cart-side.r {
  width: var(--cart-d); height: 100%;
  left: calc(50% - var(--cart-d) / 2); top: 0;
}
.cart-side.l { transform: rotateY(-90deg) translateZ(calc(var(--cart-w) / 2)); }
.cart-side.r { transform: rotateY(90deg) translateZ(calc(var(--cart-w) / 2)); }
.cart-side.t, .cart-side.b {
  width: 100%; height: var(--cart-d);
  left: 0; top: calc(50% - var(--cart-d) / 2);
}
.cart-side.t { transform: rotateX(90deg) translateZ(calc(var(--cart-h) / 2)); filter: brightness(0.85); }
.cart-side.b { transform: rotateX(-90deg) translateZ(calc(var(--cart-h) / 2)); filter: brightness(0.4); }

/* grip ridges on the top edge */
.cart-side.t i {
  position: absolute; top: 12%; bottom: 12%; width: 2px;
  background: rgba(20, 30, 50, 0.32);
}

/* face furniture */
.cart-top { display: flex; align-items: center; justify-content: space-between; }
.cart-slug {
  font-family: 'JetBrains Mono', ui-monospace, monospace;
  font-size: 11px; letter-spacing: 0.22em;
  color: color-mix(in srgb, var(--pc) 62%, #000);
}
.cart-led {
  width: 7px; height: 7px; border-radius: 50%;
  background: var(--pc); box-shadow: 0 0 12px var(--pc);
  animation: mark-pulse 2.6s ease-in-out infinite;
}
.cart-window {
  flex: 1; display: grid; place-items: center;
  margin: 10% 0;
  border: 1px solid rgba(10, 16, 30, 0.45);
  background: radial-gradient(ellipse at center, #101a2e, #05080f 78%);
  box-shadow: inset 0 2px 10px rgba(0, 0, 0, 0.75);
  color: var(--pc);
}
.cart-window svg {
  width: 46%; height: 46%;
  filter: drop-shadow(0 0 10px color-mix(in srgb, var(--pc) 80%, transparent));
}
.cart-name {
  font-family: 'JetBrains Mono', ui-monospace, monospace;
  font-size: clamp(10px, 1.15vw, 14px); letter-spacing: 0.18em; font-weight: 500;
  color: #0d1526;
  white-space: nowrap;
}
.cart-tag {
  margin-top: 5px;
  font-family: 'JetBrains Mono', ui-monospace, monospace;
  font-size: 8px; letter-spacing: 0.2em; text-transform: uppercase;
  color: color-mix(in srgb, var(--pc) 55%, #000);
}
.cart-bars { display: flex; gap: 4px; margin-top: 10%; }
.cart-bars i { height: 3px; background: color-mix(in srgb, var(--pc) 72%, #000); }
.cart-bars i:nth-child(1) { width: 40%; }
.cart-bars i:nth-child(2) { width: 22%; opacity: 0.6; }
.cart-bars i:nth-child(3) { width: 12%; opacity: 0.35; }

/* the bay it seats into */
.bay {
  position: absolute;
  left: -7%; right: -7%; top: -5%; bottom: -5%;
  transform: translateZ(calc(var(--cart-d) / -2 - 8px));
  border: 2px solid color-mix(in srgb, var(--pc) 38%, transparent);
  border-right-width: 6px;
  box-shadow: 0 0 26px color-mix(in srgb, var(--pc) 18%, transparent);
}

/* focus state: the seated module lights up */
.portal:hover .cart-face, .portal:focus-visible .cart-face {
  box-shadow:
    inset 0 0 44px color-mix(in srgb, var(--pc) 26%, transparent),
    0 0 60px color-mix(in srgb, var(--pc) 55%, transparent);
}
.portal:focus-visible { outline: none; }

/* ring flash fired when a portal takes focus */
.flash {
  position: absolute; inset: -8px;
  border: 2px solid color-mix(in srgb, var(--pc) 90%, #fff);
  box-shadow: 0 0 30px color-mix(in srgb, var(--pc) 70%, transparent);
  opacity: 0;
  pointer-events: none;
}

/* softer echo fired on hover */
.ripple {
  position: absolute; inset: 0;
  border: 1px solid var(--pc);
  opacity: 0;
  pointer-events: none;
}

/* focus state: the frame hardens up rather than just growing */
.portal:hover .ring, .portal:focus-visible .ring {
  box-shadow:
    0 0 0 1px #000,
    0 0 0 5px color-mix(in srgb, var(--pc) 28%, transparent),
    0 0 60px color-mix(in srgb, var(--pc) 70%, transparent),
    inset 0 0 0 1px color-mix(in srgb, var(--pc) 60%, transparent);
}
.portal:focus-visible { outline: none; }

/* --- the tower ----------------------------------------------------- */

.tower { position: absolute; top: 0; left: 0; transform-style: preserve-3d; pointer-events: none; }

.storey { position: absolute; top: 0; left: 0; transform-style: preserve-3d; }

/* Open truss: no walls. Everything behind the mast stays visible, which
   is the point -- the per-project backdrops read straight through it. */

/* diagonal bracing across each face */
.brace {
  position: absolute; left: 0; top: 0;
  height: 2px;
  transform-origin: 0 50%;
  background: linear-gradient(90deg,
    color-mix(in srgb, var(--accent) 30%, transparent),
    color-mix(in srgb, var(--accent) 90%, #fff) 50%,
    color-mix(in srgb, var(--accent) 30%, transparent));
  box-shadow: 0 0 7px color-mix(in srgb, var(--accent) 45%, transparent);
  opacity: 0.8;
  transition: background 600ms linear;
}

/* corner legs of the mast */
.column {
  position: absolute; left: 0; top: 0;
  width: 3px;
  background: linear-gradient(180deg,
    transparent,
    color-mix(in srgb, var(--accent) 85%, #fff) 22%,
    color-mix(in srgb, var(--accent) 85%, #fff) 78%,
    transparent);
  opacity: 0.9;
  box-shadow: 0 0 10px color-mix(in srgb, var(--accent) 75%, transparent);
  transition: background 600ms linear;
}

/* horizontal floor plate, drawn as a ring lying flat in 3D */
.deck {
  position: absolute; left: 0; top: 0;
  border-radius: 50%;
  border: 1px solid color-mix(in srgb, var(--accent) 45%, transparent);
  box-shadow:
    0 0 20px color-mix(in srgb, var(--accent) 26%, transparent),
    inset 0 0 30px rgba(0, 0, 0, 0.8);
  background: radial-gradient(ellipse at center, transparent 58%, color-mix(in srgb, var(--accent) 10%, transparent) 82%, transparent);
  transition: border-color 600ms linear, box-shadow 600ms linear;
}
.deck.major {
  border-color: color-mix(in srgb, var(--accent) 95%, #fff);
  box-shadow:
    0 0 34px color-mix(in srgb, var(--accent) 40%, transparent),
    inset 0 0 46px color-mix(in srgb, var(--accent) 16%, transparent);
}
.deck.major::after {
  content: ''; position: absolute; inset: 9%;
  border-radius: 50%;
  border: 1px dashed color-mix(in srgb, var(--accent) 26%, transparent);
}

/* level number etched onto the shaft */
.level-mark {
  position: absolute; left: 0; top: 0;
  font-family: 'JetBrains Mono', ui-monospace, monospace;
  font-size: 11px; letter-spacing: 0.3em;
  color: color-mix(in srgb, var(--accent) 85%, #fff);
  text-shadow: 0 0 10px color-mix(in srgb, var(--accent) 60%, transparent);
  white-space: nowrap;
  transition: color 600ms linear;
}

/* gantry arm: runs from the portal in to the tower skin.
   rotateY(90deg) maps the element's +X onto -Z, i.e. straight at the axis. */
.strut {
  position: absolute; top: 50%; left: 50%;
  height: 8px;
  transform-origin: 0 50%;
  /* cancel the portal's tilt first, so the arm still runs to the shaft */
  transform: rotateX(calc(var(--tilt-x, 0deg) * -1)) rotateY(calc(var(--tilt-y, 0deg) * -1))
             rotateY(90deg) translateY(-50%);
  pointer-events: none;
  opacity: 0.75;
  background:
    linear-gradient(180deg,
      color-mix(in srgb, var(--pc) 70%, transparent) 0 1px,
      transparent 1px calc(100% - 1px),
      color-mix(in srgb, var(--pc) 45%, transparent) calc(100% - 1px)),
    repeating-linear-gradient(66deg,
      color-mix(in srgb, var(--pc) 40%, transparent) 0 1px,
      transparent 1px 9px);
}

/* service rings riding up and down the shaft */
.tram {
  position: absolute; left: 0; top: 0;
  border-radius: 50%;
  border: 1px solid color-mix(in srgb, var(--accent) 90%, #fff);
  box-shadow:
    0 0 26px color-mix(in srgb, var(--accent) 70%, transparent),
    inset 0 0 22px color-mix(in srgb, var(--accent) 30%, transparent);
  opacity: 0.75;
  animation-name: tram-run;
  animation-timing-function: cubic-bezier(0.55, 0, 0.45, 1);
  animation-iteration-count: infinite;
}
@keyframes tram-run {
  0%   { transform: translateY(var(--from)) rotateX(90deg); opacity: 0 }
  12%  { opacity: 0.8 }
  88%  { opacity: 0.8 }
  100% { transform: translateY(var(--to)) rotateX(90deg); opacity: 0 }
}

/* velocity flash: brightens the whole scene while you're moving fast */
.surge {
  position: fixed; inset: 0; z-index: 15; pointer-events: none; opacity: 0;
  background:
    radial-gradient(ellipse 46% 60% at 50% 50%, color-mix(in srgb, var(--accent) 30%, transparent), transparent 72%);
  mix-blend-mode: screen;
}

/* spire + base */
.spire {
  position: absolute; left: 0; top: 0;
  width: 3px;
  background: linear-gradient(180deg, transparent, color-mix(in srgb, var(--accent) 90%, #fff));
  box-shadow: 0 0 16px var(--accent);
}
.beacon {
  position: absolute; left: 0; top: 0;
  width: 10px; height: 10px; border-radius: 50%;
  background: #fff;
  box-shadow: 0 0 22px 5px var(--accent);
  animation: beacon-blink 2.6s ease-in-out infinite;
}
@keyframes beacon-blink { 0%, 100% { opacity: 1 } 45% { opacity: 0.15 } }

.plinth {
  position: absolute; left: 0; top: 0;
  border-radius: 50%;
  border: 1px solid color-mix(in srgb, var(--accent) 45%, transparent);
  background: radial-gradient(ellipse at center, color-mix(in srgb, var(--accent) 16%, transparent), transparent 72%);
  box-shadow: 0 0 60px color-mix(in srgb, var(--accent) 30%, transparent);
}

@media (prefers-reduced-motion: reduce) {
  .beacon, .tram { animation: none !important; }
  .tram { opacity: 0 }
}

/* --- project panel -------------------------------------------------
   Filmstrip presentation on the tower's mechanism: one full-height
   panel per project, oversized name, moving at a different rate to the
   tower behind it so the two read as separate depths.                */

.readout {
  position: fixed;
  right: 0; top: 0; bottom: 0;
  width: min(620px, 50vw);
  padding: 0 clamp(26px, 4vw, 76px) 0 0;
  display: flex; align-items: center;
  z-index: 30;
  pointer-events: none;
}
.readout-inner { pointer-events: auto; width: 100%; will-change: transform, opacity; }

.readout-index {
  font-family: 'JetBrains Mono', ui-monospace, monospace;
  font-size: 11px; letter-spacing: 0.34em; color: var(--accent);
  margin-bottom: 18px;
  transition: color 500ms linear;
}
.readout-name {
  font-size: clamp(40px, 7.4vw, 112px);
  font-weight: 700; letter-spacing: -0.02em; line-height: 0.88;
  margin-bottom: 16px;
  text-shadow: 0 2px 26px rgba(0, 0, 0, 0.85);
  white-space: nowrap;          /* the name is the hero: never break it */
}
.readout-name .ch { display: inline-block; }
.readout-tag {
  font-family: 'JetBrains Mono', ui-monospace, monospace;
  font-size: 10px; letter-spacing: 0.28em; text-transform: uppercase;
  color: var(--accent); margin-bottom: 22px;
  transition: color 500ms linear;
}
.readout-blurb {
  font-size: clamp(14px, 1.5vw, 17px); line-height: 1.7; color: #c8d3e6;
  font-weight: 300; margin-bottom: 30px; max-width: 44ch;
  text-shadow: 0 1px 8px rgba(0, 0, 0, 0.9);
}

.readout-meta {
  display: flex; flex-wrap: wrap; gap: 1px;
  background: var(--line);
  border: 1px solid var(--line);
  margin-bottom: 32px;
}
.readout-meta > div { background: rgba(0, 2, 6, 0.86); padding: 14px 18px; flex: 1 1 130px; }
.readout-meta dt {
  font-family: 'JetBrains Mono', ui-monospace, monospace;
  font-size: 9px; letter-spacing: 0.24em; text-transform: uppercase;
  color: var(--ink-dim); margin-bottom: 7px;
}
.readout-meta dd { font-size: 13px; color: var(--ink); font-weight: 400; }

.enter-btn {
  display: inline-flex; align-items: center; gap: 12px;
  padding: 16px 26px;
  background: transparent;
  border: 1px solid color-mix(in srgb, var(--accent) 50%, transparent);
  color: var(--ink);
  font-family: 'JetBrains Mono', ui-monospace, monospace;
  font-size: 10px; letter-spacing: 0.26em;
  cursor: pointer;
  position: relative; overflow: hidden;
  transition: border-color 300ms, color 300ms, box-shadow 300ms;
}
.enter-btn::before {
  content: ''; position: absolute; inset: 0;
  background: var(--accent); opacity: 0.14;
  transform: translateY(101%);
  transition: transform 520ms var(--ease-out);
}
.enter-btn:hover { border-color: var(--accent); box-shadow: 0 0 30px color-mix(in srgb, var(--accent) 32%, transparent); }
.enter-btn:hover::before { transform: translateY(0); }
.enter-btn svg { width: 15px; height: 15px; fill: none; stroke: currentColor; stroke-width: 1.5; }

/* --- progress rail ------------------------------------------------ */

.rail {
  position: fixed; left: clamp(18px, 3vw, 44px); top: 50%;
  transform: translateY(-50%);
  z-index: 30;
  display: flex; flex-direction: column; gap: 14px;
}
.rail-line, .rail-thumb { display: none; }   /* replaced by filmstrip bars */
.rail-ticks { display: flex; flex-direction: column; gap: 14px; }
.rail-tick {
  width: 2px; height: 26px;
  background: rgba(255, 255, 255, 0.22);
  cursor: pointer;
  transition: background 320ms, transform 420ms var(--ease-out);
  transform-origin: 50% 50%;
}
.rail-tick:hover { background: rgba(255, 255, 255, 0.5); }
.rail-tick.on { background: var(--accent); transform: scaleX(2.6); }


/* --- landing hero -------------------------------------------------- */

.hud-btn {
  pointer-events: auto;
  background: transparent;
  border: 1px solid color-mix(in srgb, var(--accent) 35%, transparent);
  color: var(--ink-dim);
  font-family: 'JetBrains Mono', ui-monospace, monospace;
  font-size: 9px; letter-spacing: 0.22em; text-transform: uppercase;
  padding: 9px 14px; margin-left: 22px;
  cursor: pointer;
  transition: color 250ms, border-color 250ms, box-shadow 250ms;
}
.hud-btn:hover {
  color: var(--accent);
  border-color: var(--accent);
  box-shadow: 0 0 22px color-mix(in srgb, var(--accent) 28%, transparent);
}

.intro {
  position: fixed; inset: 0; z-index: 80;
  display: grid; place-items: center;
  text-align: center;
  padding: 6vh clamp(20px, 6vw, 60px);
  background:
    radial-gradient(ellipse 60% 55% at 50% 50%, color-mix(in srgb, var(--bg) 88%, transparent) 0%, color-mix(in srgb, var(--bg) 96%, transparent) 55%, var(--bg) 100%);
  backdrop-filter: blur(3px);
  -webkit-backdrop-filter: blur(3px);
}
.intro.gone { display: none; }

.intro-eyebrow {
  font-family: 'JetBrains Mono', ui-monospace, monospace;
  font-size: 9px; letter-spacing: 0.42em; text-transform: uppercase;
  color: var(--ink-faint);
  margin-bottom: 26px;
}

.intro-title {
  font-size: clamp(44px, 11vw, 132px);
  font-weight: 700; line-height: 0.92;
  letter-spacing: 0.06em;
  margin-bottom: 26px;
}
.intro-title .ch { display: inline-block; }

.slogan {
  display: flex; flex-wrap: wrap; align-items: center; justify-content: center;
  gap: clamp(10px, 2.2vw, 22px);
  font-family: 'JetBrains Mono', ui-monospace, monospace;
  font-size: clamp(9px, 1.4vw, 12px);
  letter-spacing: 0.34em; text-transform: uppercase;
  color: var(--ink);
  margin-bottom: 30px;
}
.slogan i { color: var(--accent); font-style: normal; opacity: 0.8; }

.intro-line {
  max-width: 46ch; margin: 0 auto 40px;
  font-size: clamp(14px, 1.7vw, 18px); font-weight: 300; line-height: 1.7;
  color: var(--ink-dim);
}

.intro-btn {
  display: inline-flex; align-items: center; gap: 14px;
  padding: 16px 30px;
  background: transparent;
  border: 1px solid var(--accent);
  color: var(--ink);
  font-family: 'JetBrains Mono', ui-monospace, monospace;
  font-size: 10px; letter-spacing: 0.3em;
  cursor: pointer; position: relative; overflow: hidden;
  box-shadow: 0 0 30px color-mix(in srgb, var(--accent) 22%, transparent);
  transition: box-shadow 300ms;
}
.intro-btn::before {
  content: ''; position: absolute; inset: 0;
  background: var(--accent); opacity: 0.14;
  transform: translateY(101%);
  transition: transform 520ms var(--ease-out);
}
.intro-btn:hover { box-shadow: 0 0 52px color-mix(in srgb, var(--accent) 42%, transparent); }
.intro-btn:hover::before { transform: translateY(0); }
.intro-btn svg { width: 15px; height: 15px; fill: none; stroke: currentColor; stroke-width: 1.5; }

.intro-note {
  margin-top: 34px;
  font-family: 'JetBrains Mono', ui-monospace, monospace;
  font-size: 9px; letter-spacing: 0.24em; text-transform: uppercase;
  color: var(--ink-faint);
}

/* --- about panel ---------------------------------------------------- */

.about {
  position: fixed; top: 0; right: 0; bottom: 0; z-index: 90;
  width: min(560px, 100vw);
  background: color-mix(in srgb, var(--bg) 94%, transparent);
  border-left: 1px solid color-mix(in srgb, var(--accent) 30%, transparent);
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  transform: translateX(101%);
  visibility: hidden;
}
.about.open { visibility: visible; }

.about-scroll {
  height: 100%; overflow-y: auto;
  padding: clamp(56px, 8vh, 84px) clamp(26px, 5vw, 52px) 80px;
}

.about-close {
  position: absolute; top: 20px; right: 22px; z-index: 2;
  width: 36px; height: 36px;
  background: transparent; color: var(--ink-dim);
  border: 1px solid var(--line);
  font-size: 13px; cursor: pointer;
  transition: color 220ms, border-color 220ms;
}
.about-close:hover { color: var(--accent); border-color: var(--accent); }

.about-key {
  font-family: 'JetBrains Mono', ui-monospace, monospace;
  font-size: 9px; letter-spacing: 0.28em; text-transform: uppercase;
  color: var(--accent);
  margin: 46px 0 16px;
}
.about-key:first-child { margin-top: 0; }

.about-lead { font-size: 19px; font-weight: 300; line-height: 1.6; color: var(--ink); }
.about-body, .about-foot {
  margin-top: 14px;
  font-size: 14px; font-weight: 300; line-height: 1.75; color: var(--ink-dim);
}
.about-foot {
  margin-top: 52px; padding-top: 26px;
  border-top: 1px solid var(--line);
}

/* the manual -> AI ladder */
.principle { list-style: none; counter-reset: rung; }
.principle li {
  counter-increment: rung;
  position: relative;
  padding: 0 0 20px 34px;
  border-left: 1px solid var(--line);
  margin-left: 6px;
  font-size: 13px; font-weight: 300; line-height: 1.6; color: var(--ink-dim);
}
.principle li:last-child { border-left-color: transparent; padding-bottom: 0; }
.principle li::before {
  content: ''; position: absolute; left: -5px; top: 4px;
  width: 9px; height: 9px; background: var(--bg);
  border: 1px solid var(--accent); transform: rotate(45deg);
}
.principle li span {
  display: block; margin-bottom: 5px;
  font-family: 'JetBrains Mono', ui-monospace, monospace;
  font-size: 11px; letter-spacing: 0.2em; text-transform: uppercase; color: var(--ink);
}

.stack-list dt {
  font-family: 'JetBrains Mono', ui-monospace, monospace;
  font-size: 11px; letter-spacing: 0.2em; text-transform: uppercase;
  color: var(--ink); margin-top: 20px;
}
.stack-list dt:first-child { margin-top: 0; }
.stack-list dd { margin-top: 6px; font-size: 13px; font-weight: 300; line-height: 1.65; color: var(--ink-dim); }

.sections-list { list-style: none; }
.sections-list li {
  display: flex; align-items: baseline; gap: 14px;
  padding: 13px 0; border-bottom: 1px solid var(--line);
  font-size: 13px; font-weight: 300; color: var(--ink-dim);
  cursor: pointer;
  transition: color 220ms;
}
.sections-list li:hover { color: var(--ink); }
.sections-list .slug {
  font-family: 'JetBrains Mono', ui-monospace, monospace;
  font-size: 11px; letter-spacing: 0.18em;
  color: var(--pc, var(--accent));
  width: 34px; flex: none;
}
.sections-list .nm { color: var(--ink); flex: 1; }
.sections-list .st {
  font-family: 'JetBrains Mono', ui-monospace, monospace;
  font-size: 9px; letter-spacing: 0.18em; text-transform: uppercase; color: var(--ink-faint);
}

.learn { display: flex; flex-wrap: wrap; gap: 8px; }
.learn span {
  font-family: 'JetBrains Mono', ui-monospace, monospace;
  font-size: 10px; letter-spacing: 0.14em;
  padding: 7px 12px;
  border: 1px solid color-mix(in srgb, var(--accent) 28%, transparent);
  color: var(--ink-dim);
}

@media (max-width: 900px) {
  .hud-btn { margin-left: 12px; padding: 8px 10px; font-size: 8px; }
  .about { width: 100vw; }
}


/* --- per-project theming -------------------------------------------
   Each project gets a backdrop layer (crossfaded on focus) and props
   mounted on the tower shaft at its level.                           */

.backdrops { position: fixed; inset: 0; z-index: 5; pointer-events: none; }

.tb {
  position: absolute; inset: 0;
  opacity: 0;
  color: var(--tc);
  mask-image: radial-gradient(ellipse 78% 74% at 50% 50%, #000 12%, transparent 82%);
  -webkit-mask-image: radial-gradient(ellipse 78% 74% at 50% 50%, #000 12%, transparent 82%);
}

/* the big line-art motif each theme carries */
/* the motif sits behind the tower, not behind the copy */
.tb-art {
  position: absolute; left: 6%; top: 50%;
  height: 84vh; transform: translateY(-50%);
  fill: none; stroke: currentColor; stroke-width: 1.1;
  opacity: 0.26;
}
@media (max-width: 900px) { .tb-art { left: 50%; transform: translate(-50%, -50%); } }

/* strings: a strung mesh */
.tb-mesh {
  position: absolute; inset: -10%;
  background-image:
    repeating-linear-gradient(52deg, currentColor 0 1px, transparent 1px 26px),
    repeating-linear-gradient(-52deg, currentColor 0 1px, transparent 1px 26px);
  opacity: 0.13;
  animation: tb-drift 26s linear infinite;
}
@keyframes tb-drift { to { transform: translate(26px, 26px); } }

/* court: a slow sweeping scan, like a rally replay */
.tb-scan {
  position: absolute; inset: 0;
  background: repeating-linear-gradient(180deg, currentColor 0 1px, transparent 1px 44px);
  opacity: 0.12;
}

/* arcade: pixel field and drifting blocks */
.tb-pixels {
  position: absolute; inset: 0;
  background-image:
    linear-gradient(currentColor 1px, transparent 1px),
    linear-gradient(90deg, currentColor 1px, transparent 1px);
  background-size: 22px 22px;
  opacity: 0.10;
}
.tb-sprites i {
  position: absolute; left: var(--x); top: var(--y);
  width: 14px; height: 14px;
  background: currentColor;
  box-shadow: 14px 14px 0 currentColor, -14px 14px 0 currentColor;
  opacity: 0.5;
  animation: tb-float 6.5s ease-in-out infinite;
  animation-delay: var(--d);
}
@keyframes tb-float { 0%, 100% { transform: translateY(0) } 50% { transform: translateY(-26px) } }

/* wire: a receding grid horizon */
.tb-wire {
  position: absolute; left: 0; right: 0; bottom: 0;
  height: 62vh; width: 100%;
  fill: none; stroke: currentColor; stroke-width: 0.8;
  opacity: 0.24;
}
.tb-horizon {
  position: absolute; left: 0; right: 0; bottom: 62vh; height: 1px;
  background: currentColor; opacity: 0.5;
  box-shadow: 0 0 30px 4px currentColor;
}

/* film: perforated strips and a timeline */
.tb-perf {
  position: absolute; left: 0; right: 0; height: 46px;
  background:
    repeating-linear-gradient(90deg, transparent 0 16px, currentColor 16px 30px, transparent 30px 46px);
  opacity: 0.18;
  animation: tb-run 9s linear infinite;
}
.tb-perf.top { top: 0; } .tb-perf.bottom { bottom: 0; }
@keyframes tb-run { to { background-position: 460px 0; } }
.tb-timeline {
  position: absolute; left: 6%; right: 6%; bottom: 84px; height: 2px;
  background: repeating-linear-gradient(90deg, currentColor 0 2px, transparent 2px 34px);
  opacity: 0.30;
}

/* --- props on the shaft --------------------------------------------- */

.prop {
  position: absolute; top: 50%; left: 50%;
  width: 46px; height: 46px; margin: -23px 0 0 -23px;
  color: var(--pc);
  pointer-events: none;
  will-change: opacity;
}
.prop svg {
  width: 100%; height: 100%;
  filter: drop-shadow(0 0 8px color-mix(in srgb, var(--pc) 70%, transparent));
}
/* the little bracket that bolts it to the shaft */
.prop::after {
  content: ''; position: absolute; left: 50%; bottom: -12px;
  width: 1px; height: 12px;
  background: linear-gradient(180deg, color-mix(in srgb, var(--pc) 80%, transparent), transparent);
}

/* --- warp transition ---------------------------------------------- */

.warp {
  position: fixed; inset: 0; z-index: 100;
  display: grid; place-items: center;
  pointer-events: none; opacity: 0;
}
.warp-ring {
  width: 40px; height: 40px; border-radius: 50%;
  border: 2px solid var(--accent);
  box-shadow: 0 0 60px var(--accent), inset 0 0 40px var(--accent);
  transform: scale(0);
}
.warp-flash { position: absolute; inset: 0; background: #fff; opacity: 0; }

/* --- responsive --------------------------------------------------- */

@media (max-width: 900px) {
  .readout {
    right: auto; left: 0; top: auto; bottom: 8vh;
    width: 100vw; padding: 0 22px;
    align-items: flex-end;
  }
  .readout-name { font-size: clamp(34px, 12vw, 60px); }
  .readout-blurb { margin-bottom: 20px; max-width: none; }
  .readout-meta { display: none; }
  .rail { display: none; }
  .hud-bottom { padding-bottom: 6px; }
  .hint { font-size: 9px; }
}

@media (prefers-reduced-motion: reduce) {
  .ring::before, .ring-2, .ring-3, .core, .core-glow, .ticks, .spine-pulse, .bg-grid { animation: none !important; }
}