/* pixi-effects site styles shared by every page: base, buttons, chapter heading, header, footer. Page-only styles live next to the page. */
/* ---------- base ---------- */
*,*::before,*::after{box-sizing:border-box}
html{scroll-behavior:smooth;-webkit-text-size-adjust:100%}
body{margin:0;background:var(--bg);color:var(--ink);font-family:var(--sans);font-size:17px;line-height:1.55;overflow-x:hidden;-webkit-font-smoothing:antialiased}
img{max-width:100%;height:auto;display:block}
a{color:inherit;text-decoration-color:var(--line-2);text-underline-offset:.18em}
a:hover{text-decoration-color:var(--accent)}
:focus-visible{outline:2px solid var(--accent);outline-offset:3px;border-radius:2px}
h1,h2,h3,h4{margin:0;font-weight:700;letter-spacing:-.02em;line-height:1.05}
p{margin:0}
code,pre,kbd{font-family:var(--mono)}
code{font-size:.92em;background:var(--bg-3);padding:.1em .35em;border-radius:4px}
pre code{background:none;padding:0;font-size:inherit}
.wrap{max-width:var(--max);margin:0 auto;padding:0 var(--gutter)}
.mono{font-family:var(--mono);font-size:12px;letter-spacing:.08em;text-transform:uppercase;color:var(--ink-3)}
.sr{position:absolute;width:1px;height:1px;overflow:hidden;clip:rect(0 0 0 0);white-space:nowrap}
.skip{position:absolute;left:16px;top:-60px;z-index:60;background:var(--accent);color:var(--on-accent);padding:8px 12px;border-radius:6px;font-weight:600;text-decoration:none}
.skip:focus{top:8px}
.btn{display:inline-flex;align-items:center;gap:.5em;padding:.78em 1.15em;border-radius:6px;font-weight:600;font-size:15px;text-decoration:none;border:1px solid var(--line-2);background:transparent;color:var(--ink);cursor:pointer;font-family:var(--sans);line-height:1}
.btn:hover{border-color:var(--ink)}
.btn.primary{background:var(--accent);color:var(--on-accent);border-color:var(--accent)}
.btn.primary:hover{filter:brightness(1.08)}
.btn svg{width:14px;height:14px;flex:none}

/* ---------- keyframe diamond ---------- */
.dia{display:inline-block;width:8px;height:8px;background:var(--accent);transform:rotate(45deg);flex:none}

[hidden]{display:none!important}

/* ---------- chapter heading (a track) ---------- */
.ch{display:flex;flex-wrap:wrap;align-items:center;gap:14px;margin-bottom:16px}
.ch .n{font-family:var(--mono);font-size:12px;letter-spacing:.1em;color:var(--ink-3)}
.ch h2{font-size:clamp(30px,4vw,48px);letter-spacing:-.03em;flex-basis:100%;order:3}
.ch .rule{flex:1;height:1px;background:var(--line);min-width:24px}
.deck{font-size:clamp(17px,1.4vw,20px);color:var(--ink-2);max-width:62ch;line-height:1.5}
.deck strong{color:var(--ink);font-weight:600}
.deck a{color:var(--ink)}
.deck code{background:none;padding:0;color:var(--ink);font-size:.88em}
@media (min-width:900px){
  .ch{gap:18px;margin-bottom:20px;flex-wrap:nowrap}
  .ch h2{flex-basis:auto;order:0}
}

/* ---------- site header ---------- */
.top{position:sticky;top:0;z-index:40;background:color-mix(in srgb,var(--bg) 86%,transparent);backdrop-filter:blur(12px);-webkit-backdrop-filter:blur(12px);border-bottom:1px solid var(--line)}
.top .wrap{display:flex;align-items:center;gap:8px 18px;min-height:56px;flex-wrap:wrap}
.brand{display:flex;align-items:center;gap:10px;font-weight:700;letter-spacing:-.01em;text-decoration:none;font-size:16px;white-space:nowrap;flex:none;order:1}
.top nav{display:flex;gap:6px 18px;align-items:center;font-size:14px;order:3;flex-basis:100%;padding-bottom:8px}
.top nav a{text-decoration:none;color:var(--ink-2);padding:6px 0}
.top nav a:hover,.top nav a[aria-current="page"]{color:var(--ink)}
.top nav a[aria-current="page"]{box-shadow:inset 0 -2px 0 var(--accent)}
.top nav .only-wide{display:none}
.theme{order:2;margin-left:auto;font:inherit;font-family:var(--mono);font-size:11px;letter-spacing:.08em;text-transform:uppercase;background:none;border:1px solid var(--line);color:var(--ink-3);border-radius:999px;padding:4px 9px;cursor:pointer}
.theme:hover{color:var(--ink);border-color:var(--line-2)}
@media (min-width:600px){
  .top .wrap{flex-wrap:nowrap}
  .top nav{order:2;flex-basis:auto;margin-left:auto;padding-bottom:0}
  .top nav .only-wide{display:inline}
  .theme{order:3;margin-left:0}
}
/* ---------- site footer ---------- */
.site-foot{margin-top:80px;border-top:1px solid var(--line);padding:36px 0 48px;font-size:14.5px;color:var(--ink-2)}
.site-foot .wrap{display:grid;gap:18px}
.site-foot .links{display:flex;flex-wrap:wrap;gap:8px 20px}
.site-foot .links a{color:var(--ink);text-decoration:none;border-bottom:1px solid var(--line-2)}
.site-foot .links a:hover{border-color:var(--accent)}
.site-foot .end{font-family:var(--mono);font-size:12px;letter-spacing:.06em;color:var(--ink-3);display:flex;gap:10px;align-items:center;flex-wrap:wrap}
@media (prefers-reduced-motion:reduce){ html{scroll-behavior:auto} }