/* ────────────────────────────────────────────
   A·Sc · Line Draw (scroll-synced SVG stroke)
   スクロール進捗に同期して SVG ストロークを描画
   Pure CSS + JS、外部依存ゼロ
   ──────────────────────────────────────────── */

*,*::before,*::after{box-sizing:border-box;margin:0;padding:0}
:where(html,body){line-break:strict;word-break:normal;overflow-wrap:break-word}
:where(h1,h2,h3,h4){text-wrap:balance}
:where(p,li){text-wrap:pretty}

:root{
  --bg:#f4f3ee;
  --ink:#0a0a0a;
  --muted:#6a6a6a;
  --line:#d8d6cc;
  --paper:#fff;
  --hi:#ff2d55;
  --alt:#0066ff;
  --font:'DM Sans','Noto Sans JP',sans-serif;
  --mono:'JetBrains Mono',monospace;

  /* ── Component variables ── */
  --ld-stroke:#0a0a0a;
  --ld-accent:#ff2d55;
  --ld-width:2;
  --ld-scroll:260vh;       /* 描画に使うスクロール区間 */
}

html{scroll-behavior:smooth}
body{
  background:var(--bg);color:var(--ink);
  font-family:var(--font);font-weight:400;line-height:1.65;
}
a{color:inherit;text-decoration:none}

/* ─── HEADER ─── */
header.site{
  position:sticky;top:0;z-index:50;background:var(--bg);
  padding:1rem clamp(1.2rem,4vw,3rem);
  display:flex;align-items:center;justify-content:space-between;gap:1rem;
  border-bottom:1px solid var(--ink);
}
.back{font-family:var(--mono);font-size:.78rem;letter-spacing:.18em;display:inline-flex;align-items:center;gap:.6em}
.back .arrow{transition:transform .25s}
.back:hover .arrow{transform:translateX(-.3em)}
.cell-marker{font-family:var(--mono);font-size:.78rem;letter-spacing:.22em;color:var(--hi)}

/* ─── intro / after ─── */
.intro,.after{
  max-width:1000px;margin:0 auto;
  padding:clamp(4rem,10vw,8rem) clamp(1.5rem,4vw,3rem);
  min-height:60vh;display:flex;flex-direction:column;justify-content:center;
}
.kicker{
  display:inline-block;align-self:flex-start;
  font-family:var(--mono);font-size:.78rem;letter-spacing:.25em;
  padding:.3em .9em;border:1px solid var(--ink);margin-bottom:1.5rem;
}
.intro h1{font-weight:700;font-size:clamp(2.4rem,8vw,5.4rem);line-height:1.02;letter-spacing:-.02em}
.intro .lead{font-size:clamp(1rem,1.3vw,1.1rem);color:var(--muted);max-width:38em;margin-top:1.5rem}
/* intro 上部の図形ピッカー */
.ld-pick-wrap{
  align-self:flex-start;
  display:flex;flex-direction:column;gap:.7rem;
  margin-top:2rem;
}
.ld-pick-label{
  font-family:var(--mono);font-size:.68rem;letter-spacing:.25em;color:var(--muted);
}
.scroll-cue{
  margin-top:2rem;font-family:var(--mono);font-size:.74rem;letter-spacing:.25em;color:var(--muted);
  animation:cue 1.8s cubic-bezier(.5,0,.5,1) infinite;
}
@keyframes cue{0%,100%{opacity:1;transform:translateY(0)}50%{opacity:.4;transform:translateY(.3em)}}
.after h2{font-weight:700;font-size:clamp(1.8rem,5vw,3rem);line-height:1.1;letter-spacing:-.01em}
.after p{font-size:clamp(.95rem,1.3vw,1.1rem);color:var(--muted);max-width:36em;margin-top:1.2rem}
.after code,.note code,.var span code{font-family:var(--mono);font-size:.88em;background:var(--paper);padding:.1em .35em;border:1px solid var(--line)}

/* ────────────────────────────────────────────
   COMPONENT: .line-draw
   ──────────────────────────────────────────── */
.line-draw{
  position:relative;
  height:var(--ld-scroll);
}
.ld-sticky{
  position:sticky;top:0;
  height:100vh;
  display:flex;flex-direction:column;align-items:center;justify-content:center;
  gap:1.4rem;
}
.ld-svg{
  width:min(78vmin,560px);height:auto;
  overflow:visible;
}
.ld-path{
  fill:none;
  stroke:var(--ld-stroke);
  stroke-width:var(--ld-width);
  stroke-linecap:round;
  stroke-linejoin:round;
  /* dasharray / dashoffset は JS が設定 */
}
.ld-path.ld-accent{ stroke:var(--ld-accent); stroke-width:calc(var(--ld-width) + 1); }

.ld-bar{
  width:min(78vmin,560px);height:3px;background:var(--line);position:relative;
}
.ld-bar-fill{
  position:absolute;left:0;top:0;height:100%;width:var(--ld-progress,0%);
  background:var(--hi);
}
.ld-pct{font-family:var(--mono);font-size:.74rem;letter-spacing:.2em;color:var(--muted)}

/* 図形ピッカー */
.ld-picker{
  display:flex;flex-wrap:wrap;gap:.4rem;
  max-width:min(90vw,620px);
}
.ld-chip{
  font-family:var(--mono);font-size:.72rem;letter-spacing:.08em;
  padding:.4em .9em;background:var(--paper);border:1px solid var(--ink);color:var(--ink);
  cursor:pointer;transition:background .15s,color .15s,transform .15s;
}
.ld-chip:hover{transform:translate(-1px,-1px)}
.ld-chip[aria-pressed="true"]{background:var(--hi);color:#fff;border-color:var(--hi)}
/* END COMPONENT */


/* ─── NOTES ─── */
section.notes{max-width:1000px;margin:0 auto;padding:clamp(3rem,5vw,4.5rem) clamp(1.5rem,4vw,3rem)}
.shou{
  display:flex;align-items:baseline;justify-content:space-between;gap:1rem;flex-wrap:wrap;
  padding-bottom:1rem;border-bottom:1px solid var(--ink);margin-bottom:2.5rem;
}
.shou h2{font-size:clamp(1.3rem,2vw,1.7rem);font-weight:700;letter-spacing:.04em}
.shou .no{font-family:var(--mono);font-size:.78rem;letter-spacing:.25em;color:var(--muted)}
.notes-grid{display:grid;grid-template-columns:1fr;gap:1.2rem;margin-bottom:3rem}
@media(min-width:780px){.notes-grid{grid-template-columns:repeat(3,1fr)}}
.note{position:relative;background:var(--paper);border:1px solid var(--ink);padding:1.5rem 1.4rem 1.4rem}
.note-no{position:absolute;top:1rem;right:1rem;font-family:var(--mono);font-size:.7rem;letter-spacing:.2em;color:var(--muted)}
.note h3{font-size:1.02rem;font-weight:700;margin-bottom:.7rem;letter-spacing:.02em}
.note p{font-size:.86rem;color:var(--muted);line-height:1.8}
.sub-h{font-size:1rem;font-weight:700;letter-spacing:.04em;margin:2rem 0 1rem;padding-bottom:.7rem;border-bottom:1px dashed var(--ink)}
.vars{display:grid;grid-template-columns:1fr;gap:0;border:1px solid var(--ink);background:var(--paper)}
.var{display:grid;grid-template-columns:minmax(8rem,auto) 1fr auto;gap:1rem;padding:.8rem 1rem;border-bottom:1px solid var(--line);align-items:center}
.var:last-child{border-bottom:none}
.var code{font-family:var(--mono);font-size:.82rem;color:var(--hi);font-weight:500}
.var span{font-size:.85rem;color:var(--muted);line-height:1.5}
.var em{font-family:var(--mono);font-size:.78rem;font-style:normal;color:var(--ink);background:var(--bg);padding:.15em .55em;border:1px solid var(--line);white-space:nowrap}
@media(max-width:680px){.var{grid-template-columns:1fr;gap:.3rem;padding:.9rem 1rem}.var em{justify-self:start}}

/* ─── FOOTER ─── */
footer{
  padding:2rem clamp(1.2rem,4vw,3rem) 1.5rem;
  display:flex;flex-wrap:wrap;gap:1rem;justify-content:space-between;align-items:center;
  font-family:var(--mono);font-size:.72rem;letter-spacing:.2em;color:var(--muted);
  border-top:1px solid var(--ink);
}
footer a{color:var(--ink)}

/* Reduced motion: 全線を描画済みで静止表示（JS も尊重） */
@media (prefers-reduced-motion: reduce){
  .scroll-cue{animation:none}
}