/* ==========================================================================
   chika.dev — 地下 — a subterranean developer workshop
   A single vertical isometric core sample. Hand-drawn line-illustration on
   candle-linen parchment. Three serifs, zero sans, zero mono.
   ========================================================================== */

:root{
  --topsoil:#3b2a1d;     /* deep umber-brown — body text */
  --loam:#5b4632;        /* warmed clay-brown — mid fill */
  --iron:#6e6238;        /* olive-ochre — cable labels, rules */
  --moss:#7a8050;        /* desaturated yellow-green — blobs, hover */
  --lichen:#4f5d3a;      /* deep mossy green — lower strata, links, gauge */
  --linen:#e8dcc4;       /* warm parchment — page background */
  --anthracite:#1d1812;  /* near-black warm — deep shadow lines */

  --serif-display:'Cormorant Garamond','Hoefler Text',Garamond,serif;
  --serif-body:'EB Garamond','Hoefler Text',Garamond,serif;
  --serif-margin:'IM Fell English','Hoefler Text',Garamond,serif;

  --draw-ease:cubic-bezier(0.6,0.0,0.2,1);
}

*{box-sizing:border-box;}

html{scroll-behavior:smooth;}

body{
  margin:0;
  background:var(--linen);
  color:var(--topsoil);
  font-family:var(--serif-body);
  font-size:1.0625rem;
  line-height:1.78;
  font-weight:400;
  overflow-x:hidden;
  /* faint paper grain */
  background-image:
    radial-gradient(circle at 18% 22%, rgba(110,98,56,0.05) 0 1px, transparent 1.5px),
    radial-gradient(circle at 72% 64%, rgba(59,42,29,0.045) 0 1px, transparent 1.5px),
    radial-gradient(circle at 44% 88%, rgba(79,93,58,0.04) 0 1px, transparent 1.5px);
  background-size:160px 160px,210px 210px,190px 190px;
}

em{font-style:italic;}

/* ========================== DEPTH GAUGE (right margin) ===================== */
.depth-gauge{
  position:fixed;
  top:0; right:0;
  width:108px;
  height:100vh;
  z-index:40;
  pointer-events:none;
  font-family:var(--serif-margin);
  color:var(--lichen);
}
.gauge-ruler{
  position:absolute;
  top:5vh; right:54px;
  width:40px; height:90vh;
}
.gauge-ruler line{
  stroke:var(--lichen);
  stroke-width:1.1;
  vector-effect:non-scaling-stroke;
}
.gauge-spine{stroke-width:1.4;}
.gauge-marks{
  position:absolute;
  top:5vh; right:62px;
  height:90vh;
  margin:0; padding:0;
  list-style:none;
}
.gauge-marks li{
  position:absolute;
  right:0;
  top:calc(var(--at));
  transform:translateY(-50%);
  font-style:italic;
  font-size:0.78rem;
  letter-spacing:0.04em;
  color:var(--lichen);
  white-space:nowrap;
  text-align:right;
  background:rgba(232,220,196,0.7);
  padding:0 4px;
}
.gauge-indicator{
  position:absolute;
  right:46px;
  top:5vh;
  transform:translateY(-50%);
  display:flex;
  align-items:center;
  gap:6px;
  transition:top 0.18s linear;
}
.gauge-indicator svg{
  width:16px; height:16px;
  flex:none;
}
.gauge-indicator svg path{
  fill:var(--lichen);
  stroke:var(--anthracite);
  stroke-width:0.6;
}
.gauge-stratum-label{
  font-style:italic;
  font-size:0.74rem;
  color:var(--lichen);
  background:rgba(232,220,196,0.82);
  padding:1px 5px;
  border-radius:40% 12% 38% 14% / 30% 36% 20% 32%;
  white-space:nowrap;
  max-width:120px;
}
@media (max-width:880px){
  .depth-gauge{width:74px;}
  .gauge-ruler{right:30px; width:26px;}
  .gauge-marks{right:34px;}
  .gauge-marks li{font-size:0.66rem;}
  .gauge-stratum-label{display:none;}
  .gauge-indicator{right:20px;}
}

/* ============================= CORE SAMPLE / MAIN ========================== */
.core-sample{
  width:100%;
  position:relative;
}

/* every stratum is full-bleed and at least one viewport tall */
.stratum{
  position:relative;
  width:100%;
  min-height:100vh;
  display:flex;
  align-items:center;
  overflow:hidden;
  isolation:isolate;
}
.stratum--cavern{min-height:135vh;}
.stratum--vault{min-height:118vh;}

/* tonal banding so the descent darkens as you go */
.stratum--surface{background:linear-gradient(180deg,#efe5cf 0%,#e8dcc4 55%,#e2d4 b8 100%);background:linear-gradient(180deg,#efe5cf 0%,#e8dcc4 55%,#e2d4b8 100%);}
.stratum--cable  {background:linear-gradient(180deg,#e2d4b8 0%,#dbcaa8 100%);}
.stratum--cavern {background:linear-gradient(180deg,#dbcaa8 0%,#cdb98f 100%);}
.stratum--vault  {background:linear-gradient(180deg,#cdb98f 0%,#b8a574 100%);}
.stratum--bedrock{background:linear-gradient(180deg,#b8a574 0%,#7c6c44 45%,#332a1c 100%);}

/* the line-illustration sits behind the text, full width */
.strata-art{
  position:absolute;
  inset:0;
  width:100%;
  height:100%;
  z-index:0;
}
.strata-art .ln,
.strata-art .ln *{
  stroke:var(--anthracite);
  stroke-width:1;
  vector-effect:non-scaling-stroke;
  fill:none;
  stroke-linecap:round;
  stroke-linejoin:round;
}
.art--bedrock .ln,
.art--bedrock .ln *{stroke:#0f0c08;}
.hatch-ln,.chalk-ln{
  stroke:var(--anthracite);
  stroke-width:0.8;
  vector-effect:non-scaling-stroke;
  fill:none;
}
.laptop-screen{fill:rgba(232,220,196,0.55);stroke:var(--anthracite);stroke-width:1;vector-effect:non-scaling-stroke;}
.glow-rays .ln{stroke:var(--iron);opacity:0.5;}
.chalk-text{
  font-family:var(--serif-margin);
  font-size:14px;
  fill:rgba(232,220,196,0.0);
  /* drawn as text but rendered via stroke on a near-black board */
  fill:rgba(232,220,196,0.7);
  font-style:italic;
}
.steam{stroke:var(--moss);}

/* anno text used inside SVGs (compass, etc.) */
.anno{
  font-family:var(--serif-margin);
  font-style:italic;
  font-size:13px;
  fill:var(--iron);
}
.anno--strong{fill:var(--lichen);font-size:13px;}

/* horizon line emphasised */
.horizon{stroke-width:1.4 !important;}

/* ----- engraved cross-hatch fields (generated by JS into [data-hatch]) ----- */
.hatch line{
  stroke:var(--anthracite);
  stroke-width:0.9;
  vector-effect:non-scaling-stroke;
  opacity:0.32;
}
[data-hatch="surface"] line{opacity:0.18;}
[data-hatch="cable"]   line{opacity:0.24;}
[data-hatch="cavern"]  line{opacity:0.32;}
[data-hatch="vault"]   line{opacity:0.4;}
[data-hatch="bedrock"] line{stroke:#0f0c08;opacity:0.5;}

/* --------------------------- ORGANIC BLOBS -------------------------------- */
.organic-blob path{
  fill:var(--moss);
  fill-opacity:0.16;
  stroke:var(--lichen);
  stroke-width:1;
  stroke-opacity:0.5;
  vector-effect:non-scaling-stroke;
  filter:url(#wobble);
}
/* slow 14s breathe loop, staggered */
.organic-blob{
  transform-box:fill-box;
  transform-origin:center;
  animation:breathe 14s ease-in-out infinite;
}
.blob--cable-a{animation-delay:0s;}
.blob--cable-b{animation-delay:-3.5s;}
.blob--cable-c{animation-delay:-7s;}
.blob--desk   {animation-delay:-2s;}
.blob--vault-a{animation-delay:-5.5s;}
.blob--vault-b{animation-delay:-9s;}
.blob--pool-a {animation-delay:-1s; }
.blob--pool-b {animation-delay:-6.5s;}
.blob--pool-a path,.blob--pool-b path{fill:var(--lichen);fill-opacity:0.22;stroke:var(--lichen);}

@keyframes breathe{
  0%,100%{transform:scale(1);}
  50%    {transform:scale(1.045);}
}

/* water trickle along the bedrock floor */
.water-trickle{
  stroke:var(--lichen)!important;
  stroke-width:2.4!important;
  fill:none!important;
  opacity:0.7;
  stroke-dasharray:1 9;
  animation:flow 9s linear infinite;
}
.water-trickle--2{stroke-width:1.6!important;opacity:0.5;animation-duration:13s;}
@keyframes flow{to{stroke-dashoffset:-60;}}

/* ----- path-draw setup: elements with .draw get drawn in on reveal -------- */
.draw{stroke-dasharray:var(--len,1400);stroke-dashoffset:var(--len,1400);}
.draw.fill-path{transition:fill-opacity 1.2s ease;}
.stratum.revealed .draw{
  animation:draw-in 1.6s var(--draw-ease) forwards;
  animation-delay:var(--d,0ms);
}
@keyframes draw-in{to{stroke-dashoffset:0;}}

/* text inside the cross-section */
.stratum-inner{
  position:relative;
  z-index:2;
  width:min(680px,90vw);
  margin-left:clamp(1.25rem,7vw,7rem);
  margin-right:auto;
  padding:3.5rem 0;
}
.stratum--cable .stratum-inner,
.stratum--vault .stratum-inner{
  margin-left:auto;
  margin-right:clamp(7rem,18vw,16rem);
  text-align:right;
}
@media (max-width:880px){
  .stratum--cable .stratum-inner,
  .stratum--vault .stratum-inner{
    margin-left:clamp(1.25rem,7vw,7rem);
    margin-right:auto;
    text-align:left;
  }
}

/* a faint parchment patch under each text block so it reads over line-art */
.stratum-inner::before{
  content:"";
  position:absolute;
  inset:-1.5rem -2.5rem;
  background:radial-gradient(ellipse at center,rgba(232,220,196,0.86) 0%,rgba(232,220,196,0.78) 55%,rgba(232,220,196,0) 100%);
  z-index:-1;
  border-radius:46% 12% 40% 16% / 30% 38% 24% 34%;
}
.stratum--bedrock .stratum-inner::before{
  background:radial-gradient(ellipse at center,rgba(32,26,18,0.62) 0%,rgba(32,26,18,0.4) 55%,rgba(32,26,18,0) 100%);
}

/* ============================== TYPOGRAPHY ================================ */
.site-title{
  font-family:var(--serif-display);
  font-weight:500;
  font-style:italic;
  font-size:clamp(3rem,11vw,7rem);
  line-height:0.95;
  letter-spacing:0.06em;
  color:var(--topsoil);
  margin:0 0 0.2rem;
  text-shadow:0 1px 0 rgba(232,220,196,0.6);
}
.site-title .dot{color:var(--lichen);}
.title-gloss{
  font-family:var(--serif-margin);
  font-style:italic;
  font-size:0.95rem;
  color:var(--iron);
  margin:0 0 1.6rem;
  letter-spacing:0.02em;
}

.stratum-title{
  font-family:var(--serif-display);
  font-weight:500;
  font-style:italic;
  font-variant:small-caps;
  text-transform:lowercase;
  letter-spacing:0.18em;
  font-size:clamp(2rem,5vw,3.75rem);
  color:var(--lichen);
  margin:0.2rem 0 1.2rem;
  line-height:1.1;
}

.depth-readout{
  font-family:var(--serif-margin);
  font-style:italic;
  font-size:0.82rem;
  letter-spacing:0.14em;
  color:var(--iron);
  margin:0 0 0.4rem;
  text-transform:uppercase;
}
.depth-readout--final{color:var(--moss);}
.stratum--bedrock .depth-readout{color:var(--moss);}

.stratum-text p{
  font-size:1.0625rem;
  line-height:1.78;
  color:var(--topsoil);
  margin:0 0 1.2rem;
}
.stratum--cavern .stratum-text p{color:var(--loam);}
.stratum--vault  .stratum-text p{color:var(--loam);}
.stratum--bedrock .stratum-text p{color:#e3d6bd;}
.stratum--bedrock .stratum-title{color:var(--moss);}

.cavern-aside{
  font-style:italic;
  color:var(--iron);
  font-size:1rem;
  margin:0 0 1.4rem;
}

/* scroll hint on the surface */
.scroll-hint{
  font-family:var(--serif-margin);
  font-style:italic;
  font-size:0.95rem;
  color:var(--lichen);
  letter-spacing:0.2em;
  text-transform:uppercase;
  margin:2.4rem 0 0;
  display:flex;
  align-items:center;
  gap:0.6rem;
}
.scroll-hint::after{display:none;}
.scroll-hint span{position:relative;}
.scroll-hint{animation:hint-bob 2.6s ease-in-out infinite;}
@keyframes hint-bob{0%,100%{transform:translateY(0);}50%{transform:translateY(5px);}}

/* ---------------------------- MARGINALIA ---------------------------------- */
.marginalia{
  font-family:var(--serif-margin);
  font-style:italic;
  font-size:0.78rem;
  line-height:1.5;
  color:var(--topsoil);
  opacity:0.4;
  letter-spacing:0.01em;
  margin:1.8rem 0 0;
  position:relative;
  padding-left:1.4rem;
  max-width:34rem;
}
.marginalia::before{
  content:"";
  position:absolute;
  left:0; top:0.7em;
  width:1rem; height:0;
  border-top:1px solid currentColor;
}
.stratum--cable .marginalia,
.stratum--vault .marginalia{
  padding-left:0; padding-right:1.4rem;
  margin-left:auto;
}
.stratum--cable .marginalia::before,
.stratum--vault .marginalia::before{left:auto;right:0;}
.stratum--bedrock .marginalia{color:var(--moss);opacity:0.65;}
@media (max-width:880px){
  .stratum--cable .marginalia,.stratum--vault .marginalia{padding-left:1.4rem;padding-right:0;}
  .stratum--cable .marginalia::before,.stratum--vault .marginalia::before{left:0;right:auto;}
}

/* ----------------------- CABLE MANIFEST (stratum II) ---------------------- */
.cable-manifest{
  list-style:none;
  margin:1.4rem 0 0;
  padding:0;
  display:inline-block;
  text-align:left;
}
.cable-manifest li{
  font-family:var(--serif-margin);
  font-style:italic;
  font-size:0.92rem;
  line-height:1.9;
  color:var(--iron);
  position:relative;
  padding-left:1.6rem;
}
.cable-manifest li::before{
  content:"";
  position:absolute; left:0; top:0.85em;
  width:1.1rem; height:0;
  border-top:1.4px solid var(--iron);
  transform-origin:left center;
  transform:rotate(30deg);
}
.cable-manifest .cm-name{
  color:var(--lichen);
  font-style:italic;
  letter-spacing:0.02em;
}
.cable-manifest .cm-note{color:var(--loam);opacity:0.85;}
.cable-manifest li:hover .cm-name{color:var(--moss);}

/* ----------------------- TOME INDEX (stratum IV) -------------------------- */
.tome-index{
  list-style:none;
  margin:1.4rem 0 0;
  padding:0;
  display:inline-block;
  text-align:left;
}
.tome-index li{margin:0.1rem 0;}
.ti-spine{
  display:inline-block;
  font-family:var(--serif-display);
  font-style:italic;
  font-variant:small-caps;
  text-transform:lowercase;
  letter-spacing:0.1em;
  font-size:1.05rem;
  color:var(--loam);
  padding:0.15rem 0.9rem 0.15rem 0.3rem;
  border-left:2px solid var(--iron);
  background:linear-gradient(90deg,rgba(122,128,80,0.0),rgba(122,128,80,0.0));
  transform:skewX(-2deg);
  transition:transform 0.32s var(--draw-ease),color 0.32s ease,background 0.32s ease;
  cursor:default;
}
.ti-spine:hover,
.ti-spine.tilt{
  transform:skewX(-2deg) translateX(8px) rotate(-1.4deg);
  color:var(--lichen);
  background:linear-gradient(90deg,rgba(122,128,80,0.18),rgba(122,128,80,0.0));
}

/* --------------------- ETCHED CONTACT (bedrock footer) -------------------- */
.etched-contact{
  list-style:none;
  margin:1.6rem 0 1.8rem;
  padding:0;
  display:inline-block;
  text-align:left;
}
.etched-contact li{
  font-family:var(--serif-margin);
  font-style:italic;
  font-size:0.95rem;
  line-height:2;
  color:#d8c9ad;
  letter-spacing:0.04em;
  display:flex;
  gap:1rem;
}
.etched-contact .ec-key{
  color:var(--moss);
  min-width:9.5rem;
  text-transform:uppercase;
  font-size:0.78rem;
  letter-spacing:0.12em;
  padding-top:0.15em;
}
.etched-contact .ec-val{
  color:#e6d8be;
  text-shadow:0 1px 0 rgba(0,0,0,0.5),0 -1px 0 rgba(232,220,196,0.08);
}
.bedrock-colophon{
  font-family:var(--serif-margin);
  font-style:italic;
  font-size:0.82rem;
  color:#bdb08a;
  margin:0 0 0.6rem;
  max-width:32rem;
}

/* ---------------------------------------------------------------------------
   Reduced motion: stop the breathe loop & flows, snap path-draw to complete.
   Layout stays fully intact.
   --------------------------------------------------------------------------- */
@media (prefers-reduced-motion:reduce){
  .organic-blob{animation:none;}
  .water-trickle{animation:none;stroke-dasharray:none;}
  .scroll-hint{animation:none;}
  .draw{stroke-dasharray:none!important;stroke-dashoffset:0!important;}
  .stratum.revealed .draw{animation:none;}
  html{scroll-behavior:auto;}
}