/* ============================================================
   FOUNDATION — design-system contract (Layer 1)
   Semantic tokens + base + utilities. Every page links this.
   A STYLE THEME overrides these :root values via [data-style="x"]
   (see ds/styles/). A PROJECT sets only --brand-* (see ds/projects + brands).
   The baseline values below = the site's original Swiss-minimal look.
   ============================================================ */
:root{
  /* surfaces */
  --paper:#FFFFFF; --card:#FFFFFF; --wash:#F5F5F3;
  --elev:color-mix(in srgb, var(--ink) 5%, var(--paper)); /* elevated hover surface, re-skins per theme */
  --line:#EBEBEB; --line-strong:#D6D6D6;
  /* ink */
  --ink:#0E0E0E; --slate:#4D4D4D; --steel:#7A7A7A; --stone:#A3A3A3;
  /* brand / accent — project layer fills --brand (see brands.css) */
  --brand:#0E0E0E; --brand-deep:#000000; --on-brand:#FFFFFF;
  --accent:var(--brand); --accent-deep:var(--brand-deep); --on-accent:var(--on-brand);
  /* shape */
  --r-xs:3px; --r-sm:6px; --r-md:10px; --r-lg:16px; --r-pill:9999px;
  --content:1180px; --gutter:clamp(20px,4.5vw,36px); --section:clamp(52px,7vw,88px);
  /* spacing scale (4px base · 96px section rhythm — mirrors the studied systems) */
  --s-1:4px; --s-2:8px; --s-3:12px; --s-4:16px; --s-5:24px; --s-6:32px; --s-7:48px; --s-8:96px;
  /* elevation */
  --sh-1:0 2px 8px -3px rgba(0,0,0,.06);
  --sh-2:0 6px 18px -6px rgba(0,0,0,.08);
  --sh-3:0 22px 48px -16px rgba(0,0,0,.12);
  /* type */
  --display:'Google Sans Flex',-apple-system,sans-serif;
  --sans:'Inter',-apple-system,BlinkMacSystemFont,'Segoe UI',Roboto,Helvetica,Arial,sans-serif;
  --mono:'IBM Plex Mono',ui-monospace,SFMono-Regular,Menlo,monospace; /* micro-label face (per theme) */
  --code:'IBM Plex Mono',ui-monospace,SFMono-Regular,Menlo,monospace; /* fixed monospace for code/tabular content */
  /* motion */
  --ease:cubic-bezier(.22,.61,.36,1);
  --ease-out:cubic-bezier(.16,1,.3,1);
  --dur-fast:.2s; --dur:.35s; --dur-slow:.8s;
}

/* base */
*{box-sizing:border-box;margin:0;padding:0}
html{scroll-behavior:smooth;scroll-padding-top:92px}
body{font-family:var(--sans);color:var(--slate);background:var(--paper);line-height:1.55;-webkit-font-smoothing:antialiased;text-rendering:optimizeLegibility}
img{max-width:100%;display:block}
a{color:inherit;text-decoration:none}
::selection{background:var(--ink);color:var(--paper)}

/* in-page theme crossfade only (cross-document nav transition disabled — buggy snapshots on Safari) */
@keyframes vt-in{from{opacity:0;transform:translateY(10px)}to{opacity:1;transform:none}}
::view-transition-new(root){animation:vt-in .35s var(--ease-out)}

/* layout / type */
.wrap{max-width:var(--content);margin:0 auto;padding:0 var(--gutter)}
h1,h2{font-family:var(--display);font-weight:600;line-height:1.02;letter-spacing:-.035em;color:var(--ink)}
h2{font-size:clamp(30px,4.2vw,48px)}
.chap{display:flex;align-items:baseline;gap:18px;border-top:1px solid var(--line-strong);padding-top:16px;margin-bottom:48px}
.chap .no{font-family:var(--mono);font-size:13px;font-weight:600;color:var(--steel);letter-spacing:.08em}
.chap .lab{font-family:var(--display);font-size:12.5px;font-weight:700;letter-spacing:.14em;text-transform:uppercase;color:var(--ink)}
.chap .rule{display:none}

/* link underline */
.ul{position:relative;padding-bottom:2px}
.ul::after{content:"";position:absolute;left:0;bottom:0;height:1.5px;width:100%;background:currentColor;transform:scaleX(0);transform-origin:right;transition:transform .35s var(--ease)}
.ul:hover::after{transform:scaleX(1);transform-origin:left}

/* buttons */
.btn{display:inline-flex;align-items:center;gap:9px;font-family:var(--display);font-weight:600;font-size:14px;padding:13px 24px;border-radius:var(--r-sm);transition:transform .25s var(--ease),box-shadow .25s var(--ease),background .2s;cursor:pointer;border:1.5px solid transparent;line-height:1.3}
.btn-primary{background:var(--ink);color:#fff}
.btn-primary:hover{transform:translateY(-2px);box-shadow:var(--sh-2)}
.btn-secondary{background:transparent;color:var(--ink);border-color:var(--line-strong)}
.btn-secondary:hover{border-color:var(--ink)}
.btn .ar{transition:transform .25s var(--ease)}
.btn:hover .ar{transform:translateX(4px)}

/* capability marquee */
.marq{overflow:hidden;border-top:1px solid var(--line);border-bottom:1px solid var(--line);padding:15px 0;background:var(--paper)}
.marq-track{display:flex;gap:52px;width:max-content;white-space:nowrap;animation:marq 30s linear infinite}
.marq span{font-family:var(--mono);font-size:12px;font-weight:500;letter-spacing:.2em;text-transform:uppercase;color:var(--steel)}
@keyframes marq{from{transform:translateX(0)}to{transform:translateX(-50%)}}
.marq:hover .marq-track{animation-play-state:paused}

/* footer — ultra-minimal hairline bar */
footer{border-top:1px solid var(--line);background:var(--paper);padding:30px 0}
.foot{display:flex;align-items:center;justify-content:space-between;gap:18px;flex-wrap:wrap}
.foot .nm{font-family:var(--display);font-weight:700;font-size:14px;color:var(--ink)}
.foot .links{display:flex;gap:22px;font-size:13px;font-weight:500;color:var(--steel)}
.foot .links a{transition:color .2s}
.foot .links a:hover{color:var(--ink)}
.foot .cr{font-size:12px;color:var(--stone)}
@media(max-width:560px){.foot{gap:12px}.foot .cr{width:100%;order:3}}

/* reveal-on-scroll — initial state; ds/motion.js (GSAP) animates in */
.reveal{opacity:0;transform:translateY(26px);transition:opacity var(--dur-slow) var(--ease-out),transform var(--dur-slow) var(--ease-out)}
.reveal.in{opacity:1;transform:none}
.reveal.d1{transition-delay:.08s}
.reveal.d2{transition-delay:.16s}

@media(prefers-reduced-motion:reduce){
  .marq-track{animation:none}
  .reveal{opacity:1;transform:none;transition:none}
}