/* ═══════════════════════════════════════════════════════════
   祇園地下構想 — Gion Underground
   ═══════════════════════════════════════════════════════════ */

:root{
  --bg:#06070a;
  --ink:#eef1f5;
  --dim:#8d94a1;
  --dimmer:#5b6270;
  --gold:#e0b978;        /* 提灯の灯り */
  --bengara:#b2503c;     /* 弁柄色 */
  --cool:#a9cdf7;        /* 地下の光 */
  --line:rgba(255,255,255,.13);
  --mincho:"Shippori Mincho","Hiragino Mincho ProN","Yu Mincho",serif;
  --gothic:"Zen Kaku Gothic New","Hiragino Sans","Noto Sans JP",system-ui,sans-serif;
  --mono:"Inter",ui-monospace,"SF Mono",Menlo,monospace;
  --pad:clamp(20px,4vw,64px);
}

*{box-sizing:border-box}
html{scroll-behavior:auto}
html,body{margin:0;padding:0}
body{
  background:var(--bg);
  color:var(--ink);
  font-family:var(--gothic);
  font-weight:400;
  -webkit-font-smoothing:antialiased;
  overflow-x:hidden;
  cursor:default;
}
body.locked{overflow:hidden;height:100vh}

/* ── 3D レイヤー ─────────────────────────── */
#bg{
  position:fixed; inset:0; width:100vw; height:100vh;
  display:block; z-index:0;
}
#vignette{
  position:fixed; inset:0; z-index:1; pointer-events:none;
  background:radial-gradient(ellipse at 50% 48%, transparent 46%, rgba(0,0,0,.62) 100%);
}
#grain{
  position:fixed; inset:-50%; z-index:2; pointer-events:none; opacity:.045;
  background-image:url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='140' height='140'%3E%3Cfilter id='n'%3E%3CfeTurbulence type='fractalNoise' baseFrequency='.85' numOctaves='3'/%3E%3C/filter%3E%3Crect width='140' height='140' filter='url(%23n)'/%3E%3C/svg%3E");
  animation:grain 1.1s steps(4) infinite;
}
@keyframes grain{
  0%{transform:translate(0,0)}25%{transform:translate(-3%,2%)}
  50%{transform:translate(2%,-3%)}75%{transform:translate(-2%,-2%)}
  100%{transform:translate(0,0)}
}

/* ── ローディング ─────────────────────────── */
#loader{
  position:fixed; inset:0; z-index:100;
  display:flex; flex-direction:column; align-items:center; justify-content:center;
  gap:22px; background:var(--bg);
  transition:opacity .9s ease, visibility .9s;
}
#loader.done{opacity:0; visibility:hidden; pointer-events:none}
.loader-ring{position:relative; width:120px; height:120px}
.loader-ring svg{width:100%; height:100%; transform:rotate(-90deg)}
.lr-bg{fill:none; stroke:rgba(255,255,255,.09); stroke-width:1}
.lr-fg{
  fill:none; stroke:var(--gold); stroke-width:1.4; stroke-linecap:round;
  stroke-dasharray:339.3; stroke-dashoffset:339.3;
  transition:stroke-dashoffset .45s cubic-bezier(.2,.8,.2,1);
}
.loader-num{
  position:absolute; inset:0; display:flex; align-items:center; justify-content:center;
  font-family:var(--mono); font-size:15px; letter-spacing:.14em; color:var(--gold);
}
.loader-num::after{content:"%"; font-size:9px; margin-left:3px; opacity:.6; align-self:center}
.loader-label{font-family:var(--mincho); font-size:24px; letter-spacing:.34em; margin:0; padding-left:.34em}
.loader-sub{font-family:var(--mono); font-size:9.5px; letter-spacing:.32em; color:var(--dimmer); margin:-10px 0 0; padding-left:.32em}
#enter-btn{
  margin-top:14px; padding:13px 40px; background:transparent; color:var(--gold);
  border:1px solid rgba(224,185,120,.4); border-radius:999px; cursor:pointer;
  font-family:var(--gothic); font-size:13px; letter-spacing:.3em; padding-left:calc(40px + .3em);
  transition:background .35s, border-color .35s, color .35s;
}
#enter-btn:hover{background:rgba(224,185,120,.1); border-color:var(--gold)}

/* ── HUD ─────────────────────────────────── */
#hud{
  position:fixed; z-index:20; top:0; left:0; right:0;
  display:flex; align-items:center; justify-content:space-between;
  padding:calc(var(--pad)*.6) var(--pad);
  pointer-events:none; opacity:0; transition:opacity .8s ease .3s;
  mix-blend-mode:difference;
}
body.ready #hud{opacity:1}
.hud-left{display:flex; align-items:center; gap:13px}
.hud-ring{width:44px; height:44px; transform:rotate(-90deg); flex:none}
.hr-bg{fill:none; stroke:rgba(255,255,255,.16); stroke-width:1}
.hr-fg{fill:none; stroke:#fff; stroke-width:1.5; stroke-linecap:round; stroke-dasharray:119.4; stroke-dashoffset:119.4}
.hud-titles{display:flex; flex-direction:column; line-height:1.35}
.hud-idx{font-family:var(--mono); font-size:9.5px; letter-spacing:.26em; color:#9aa0ab}
.hud-name{font-family:var(--mincho); font-size:15px; letter-spacing:.2em}
.hud-depth{
  display:flex; align-items:baseline; gap:5px; opacity:0;
  transition:opacity .6s ease; font-family:var(--mono);
}
.hud-depth.on{opacity:1}
.hd-label{font-size:9px; letter-spacing:.26em; color:#9aa0ab; margin-right:4px}
.hd-value{font-size:26px; font-weight:300; font-variant-numeric:tabular-nums}
.hd-unit{font-size:11px; color:#9aa0ab}

/* ── チャプターナビ ───────────────────────── */
#chapter-nav{
  position:fixed; z-index:20; right:var(--pad); top:50%; transform:translateY(-50%);
  display:flex; flex-direction:column; gap:13px; align-items:flex-end;
  opacity:0; transition:opacity .8s ease .5s;
}
body.ready #chapter-nav{opacity:1}
.nav-item{
  display:flex; align-items:center; gap:9px; background:none; border:0; padding:0;
  cursor:pointer; color:var(--dimmer); font-family:var(--gothic); font-size:11px;
  letter-spacing:.14em; transition:color .35s;
}
.nav-item span{opacity:0; transform:translateX(6px); transition:opacity .35s, transform .35s; white-space:nowrap}
.nav-item i{
  display:block; width:7px; height:7px; border-radius:50%; flex:none;
  border:1px solid rgba(255,255,255,.3); transition:all .35s;
}
.nav-item:hover span,.nav-item.on span{opacity:1; transform:none}
.nav-item:hover,.nav-item.on{color:var(--ink)}
.nav-item.on i{background:var(--gold); border-color:var(--gold); box-shadow:0 0 9px rgba(224,185,120,.75)}

/* ── スクロールヒント ─────────────────────── */
#scroll-hint{
  position:fixed; z-index:20; bottom:calc(var(--pad)*.8); left:50%; transform:translateX(-50%);
  display:flex; flex-direction:column; align-items:center; gap:9px;
  font-family:var(--mono); font-size:9px; letter-spacing:.34em; color:var(--dimmer);
  opacity:0; transition:opacity .7s ease;
}
body.ready #scroll-hint{opacity:1}
#scroll-hint.hide{opacity:0 !important}
#scroll-hint i{display:block; width:1px; height:44px; background:linear-gradient(180deg,var(--gold),transparent); animation:drop 2.1s ease-in-out infinite}
@keyframes drop{0%{transform:scaleY(0); transform-origin:top}45%{transform:scaleY(1); transform-origin:top}55%{transform:scaleY(1); transform-origin:bottom}100%{transform:scaleY(0); transform-origin:bottom}}

/* ── ストーリー / チャプター ───────────────── */
#story{position:relative; z-index:10}
.ch{position:relative}
.stage{
  position:sticky; top:0; height:100vh; height:100svh;
  overflow:hidden; pointer-events:none;
}
.cap{
  position:absolute; inset:0; display:flex; padding:calc(var(--pad)*2.2) var(--pad);
}
.c-mid{align-items:center; justify-content:center; text-align:center; flex-direction:column}
.c-left{align-items:flex-start; justify-content:center; flex-direction:column; text-align:left;
        padding-right:45vw}
.c-left>*{width:100%; max-width:520px}
.c-right{align-items:flex-end; justify-content:center; flex-direction:column; text-align:left;
         padding-left:45vw}
.c-right>*{width:100%; max-width:440px}
.c-top{align-items:center; justify-content:flex-start; text-align:center; flex-direction:column}
.c-bottom{align-items:center; justify-content:flex-end; text-align:center; flex-direction:column;
          padding-bottom:calc(var(--pad)*1.6)}
.c-card{align-items:center; justify-content:flex-start; padding-right:50vw}

/* テキスト行 */
.l,.cap ul,.cap ol,.cap .card,.outro-end>div{
  opacity:0; transform:translateY(22px);
  transition:opacity .05s linear, transform .05s linear;
  will-change:opacity,transform;
}
.l{margin:0 0 .55em; line-height:1.85; letter-spacing:.08em; text-wrap:balance;
   text-shadow:0 1px 3px rgba(0,0,0,.7), 0 6px 34px rgba(0,0,0,.55)}
.xs{font-size:10.5px; line-height:1.9}
.sm{font-size:12px}
.md{font-size:clamp(15px,1.55vw,19px)}
.lg{font-size:clamp(22px,3.1vw,40px); line-height:1.7; letter-spacing:.13em}
.xl{font-size:clamp(34px,5.6vw,78px); line-height:1.42; letter-spacing:.2em}
.mincho{font-family:var(--mincho); font-weight:500}
.mono{font-family:var(--mono); letter-spacing:.28em; font-weight:400}
.dim{color:var(--dim)}
.accent{color:var(--cool)}
.glow{text-shadow:0 0 34px rgba(224,185,120,.45), 0 0 90px rgba(224,185,120,.18)}
.l b{font-weight:700; color:#fff}
.l em{
  font-style:normal; font-family:var(--mono); font-size:11px; letter-spacing:.2em;
  color:var(--gold); display:inline-block; min-width:52px; margin-right:12px;
}

/* 課題リスト */
.issues ul{list-style:none; margin:0; padding:0; border-top:1px solid var(--line)}
.issues li{
  display:flex; align-items:baseline; gap:16px; padding:15px 2px;
  border-bottom:1px solid var(--line);
}
.issues b{font-family:var(--mincho); font-size:19px; letter-spacing:.22em; min-width:4.6em; font-weight:500}
.issues span{font-size:12.5px; color:#b3bac6; letter-spacing:.06em}
.issues li,.feats li,.steps li{text-shadow:0 1px 3px rgba(0,0,0,.7), 0 6px 34px rgba(0,0,0,.5)}

/* 機能リスト */
.feats ul{list-style:none; margin:0; padding:0; display:flex; flex-direction:column; gap:9px}
.feats li{
  font-family:var(--mincho); font-size:clamp(17px,2vw,25px); letter-spacing:.2em;
  padding:9px 0 9px 26px; position:relative;
}
.feats li::before{
  content:""; position:absolute; left:0; top:50%; width:9px; height:9px; margin-top:-4px;
  border:1px solid var(--gold); border-radius:50%;
}

/* 段階リスト */
.steps ol{list-style:none; margin:0; padding:0; counter-reset:s}
.steps li{
  display:grid; grid-template-columns:44px 1fr; gap:4px 16px; align-items:baseline;
  padding:13px 0; border-bottom:1px solid var(--line);
  transition:opacity .4s, color .4s;
}
.steps i{
  font-family:var(--mono); font-size:10.5px; letter-spacing:.16em; color:var(--gold);
  font-style:normal; grid-row:span 2;
}
.steps b{font-size:16px; letter-spacing:.16em; font-weight:500}
.steps span{grid-column:2; font-size:12px; color:var(--dim); letter-spacing:.05em; line-height:1.7}
.vsteps i{color:var(--cool)}

/* 解決カード */
.card{
  background:linear-gradient(150deg, rgba(18,21,27,.96), rgba(8,10,14,.93));
  border:1px solid var(--line); border-radius:3px;
  padding:30px 32px 28px; position:relative; max-width:440px;
  backdrop-filter:blur(14px); -webkit-backdrop-filter:blur(14px);
}
.card-no{
  position:absolute; top:22px; right:26px;
  font-family:var(--mono); font-size:36px; font-weight:300; color:rgba(255,255,255,.09);
}
.card h3{
  font-family:var(--mincho); font-size:29px; letter-spacing:.26em; margin:0 0 16px;
  font-weight:500;
}
.card h3::after{content:""; display:block; width:26px; height:1px; background:var(--gold); margin-top:15px}
.card p{margin:0; font-size:13.5px; line-height:2.05; letter-spacing:.06em; color:#c8ced8}
.card p b{color:#fff}
.card .tag{
  margin-top:17px; font-family:var(--mono); font-size:9.5px; letter-spacing:.22em;
  color:var(--bengara); border-top:1px solid var(--line); padding-top:13px;
}

/* 結び */
.outro-end hr{border:0; border-top:1px solid var(--line); margin:26px auto; width:70px}
.outro-end .l{margin-bottom:.45em}

/* ── ビューア ─────────────────────────────── */
.viewer-stage{
  display:flex; flex-direction:column; align-items:center; justify-content:center;
  gap:clamp(10px,1.6vh,20px); padding:calc(var(--pad)*.9) var(--pad);
  pointer-events:auto;
  background:radial-gradient(ellipse at 50% 45%, #0d1016 0%, #05060a 72%);
}
.viewer-head{text-align:center}
.viewer-head .shown{opacity:1; transform:none; margin-bottom:8px}
.viewer-head h2{
  font-size:clamp(21px,2.7vw,34px); letter-spacing:.2em; margin:0 0 8px; font-weight:500;
}
.viewer-hint{font-size:11px; letter-spacing:.14em; color:var(--dimmer); margin:0}
.viewer-wrap{
  position:relative; width:min(1080px,100%); flex:1 1 auto; min-height:0;
  border:1px solid var(--line); border-radius:3px; overflow:hidden;
  background:linear-gradient(180deg,#0a0d13,#06080c);
}
#viewer{display:block; width:100%; height:100%; touch-action:none; cursor:grab}
#viewer:active{cursor:grabbing}
.viewer-loading{
  position:absolute; inset:0; display:grid; place-items:center;
  font-family:var(--mono); font-size:10px; letter-spacing:.28em; color:var(--dimmer);
  transition:opacity .5s;
}
.viewer-loading.hide{opacity:0; pointer-events:none}
.v-reset{
  position:absolute; top:12px; right:12px; z-index:3;
  background:rgba(10,12,17,.7); color:var(--dim); border:1px solid var(--line);
  border-radius:2px; padding:7px 13px; cursor:pointer;
  font-family:var(--mono); font-size:9px; letter-spacing:.22em;
  transition:color .3s, border-color .3s;
}
.v-reset:hover{color:var(--gold); border-color:rgba(224,185,120,.45)}
.v-readout{
  position:absolute; left:12px; bottom:12px; z-index:3;
  font-family:var(--mono); font-size:9.5px; letter-spacing:.22em; color:var(--dimmer);
}
.viewer-ui{
  display:flex; flex-wrap:wrap; gap:clamp(12px,2.4vw,34px);
  justify-content:center; align-items:flex-start; width:min(1080px,100%);
}
.v-group{display:flex; flex-direction:column; gap:7px; align-items:center}
.v-label{font-family:var(--mono); font-size:8.5px; letter-spacing:.26em; color:var(--dimmer)}
.v-btns{display:flex; flex-wrap:wrap; gap:5px; justify-content:center}
.v-btns.v-parts{max-width:430px}
.v-btns button{
  background:transparent; border:1px solid var(--line); border-radius:999px;
  color:var(--dim); padding:6px 14px; cursor:pointer;
  font-family:var(--gothic); font-size:11px; letter-spacing:.1em;
  transition:all .28s;
}
.v-btns button:hover{color:var(--ink); border-color:rgba(255,255,255,.3)}
.v-btns button.on{color:#0a0b0e; background:var(--gold); border-color:var(--gold); font-weight:500}

/* 断面スライダー */
.v-cutwrap{min-width:150px}
#v-cut{
  -webkit-appearance:none; appearance:none; width:150px; height:22px;
  background:transparent; cursor:ew-resize;
}
#v-cut::-webkit-slider-runnable-track{
  height:1px; background:rgba(255,255,255,.24);
}
#v-cut::-moz-range-track{height:1px; background:rgba(255,255,255,.24)}
#v-cut::-webkit-slider-thumb{
  -webkit-appearance:none; appearance:none; width:11px; height:11px; margin-top:-5px;
  border-radius:50%; background:var(--dim); border:0; transition:background .25s, box-shadow .25s;
}
#v-cut::-moz-range-thumb{
  width:11px; height:11px; border-radius:50%; background:var(--dim); border:0;
}
.v-cutwrap.on #v-cut::-webkit-slider-thumb{background:var(--gold); box-shadow:0 0 10px rgba(224,185,120,.7)}
.v-cutwrap.on #v-cut::-moz-range-thumb{background:var(--gold)}
.v-cutwrap.on .v-label{color:var(--gold)}
/* パーツは「全部オン」が初期状態なので、控えめな塗りにする */
.v-parts button.on{
  color:var(--ink); background:rgba(255,255,255,.09);
  border-color:rgba(255,255,255,.34); font-weight:400;
}
.v-parts button:not(.on){opacity:.5; text-decoration:line-through; text-decoration-color:rgba(255,255,255,.35)}

/* ── フォールバック ───────────────────────── */
#webgl-fallback{
  position:fixed; inset:auto 0 0 0; z-index:60; padding:16px;
  background:#12151b; text-align:center; font-size:13px; color:var(--dim);
}

/* ── レスポンシブ ─────────────────────────── */
@media (max-width:880px){
  :root{--pad:20px}
  #chapter-nav{display:none}
  .c-left,.c-right,.c-card{padding-left:var(--pad); padding-right:var(--pad)}
  .c-left,.c-card{align-items:flex-start; justify-content:flex-end; padding-bottom:16vh}
  .c-right{align-items:flex-start; justify-content:flex-end; padding-bottom:16vh}
  .c-left>*,.c-right>*{max-width:100%}
  .cap{padding-top:16vh}
  .card{padding:22px 20px}
  .card-no{font-size:26px; top:16px; right:18px}
  .hud-depth .hd-value{font-size:20px}
  .viewer-ui{gap:12px}
  .viewer-stage{padding-top:64px}
  .viewer-head h2{font-size:19px; letter-spacing:.14em}
  .v-btns.v-parts{max-width:100%}
  .viewer-hint{font-size:10px}
}
@media (max-height:620px){
  .viewer-head h2{font-size:19px}
  .viewer-head .shown,.viewer-hint{display:none}
}
@media (prefers-reduced-motion:reduce){
  #grain{animation:none}
  #scroll-hint i{animation:none}
}