@import url('https://fonts.googleapis.com/css2?family=Fira+Code:wght@300;400;500;600;700&family=Share+Tech+Mono&display=swap');

:root{
--ink:#000000;
--paper:#ffffff;
--mono:'Share Tech Mono','Fira Code',ui-monospace,SFMono-Regular,Menlo,Consolas,'Noto Sans SC','PingFang SC','Microsoft YaHei',monospace;
--r:18px;
--gutter:clamp(1rem,5vw,4.5rem);
--topbar:118px;
}

*,*::before,*::after{box-sizing:border-box}

html{overflow-x:hidden;scroll-behavior:smooth;-webkit-text-size-adjust:100%}
body{margin:0;overflow-x:hidden;background:var(--paper);color:var(--ink);font-family:var(--mono);font-size:17px;line-height:1.72;letter-spacing:.01em}
a{color:inherit}
img{max-width:100%}
p{margin:0 0 1.05rem}
:focus-visible{outline:3px solid var(--ink);outline-offset:3px}

/* top bar */
.topbar{position:sticky;top:0;z-index:60;background:var(--paper);border-bottom:2px solid var(--ink)}
.masthead{display:flex;align-items:center;justify-content:space-between;gap:1rem;padding:.7rem var(--gutter)}
.brand{display:inline-flex;align-items:center;min-height:44px;padding-right:.5rem;font-size:clamp(1.25rem,3.4vw,1.7rem);font-weight:700;letter-spacing:-.05em;text-decoration:none}
.mast-actions{display:flex;align-items:center;gap:.55rem}
.btn{display:inline-flex;align-items:center;justify-content:center;min-height:44px;padding:.5rem 1.1rem;border:2px solid var(--ink);border-radius:var(--r);background:var(--ink);color:var(--paper);font-family:inherit;font-size:.95rem;font-weight:600;text-decoration:none;cursor:pointer;transition:background .18s,color .18s,transform .18s}
.btn:hover{background:var(--paper);color:var(--ink);transform:translateY(-2px)}
.btn-inv{background:var(--paper);color:var(--ink)}
.btn-inv:hover{background:var(--ink);color:var(--paper)}
.burger{min-height:44px;min-width:54px;padding:.5rem .8rem;border:2px solid var(--ink);border-radius:var(--r);background:var(--paper);color:var(--ink);font-family:inherit;font-size:.95rem;cursor:pointer;transition:background .18s,color .18s}
.burger:hover{background:var(--ink);color:var(--paper)}

.strip{border-top:2px solid var(--ink);background:var(--paper)}
.strip ul{display:flex;gap:.4rem;margin:0;padding:.5rem var(--gutter);list-style:none;overflow-x:auto;scrollbar-width:none}
.strip ul::-webkit-scrollbar{display:none}
.strip a{display:inline-flex;align-items:center;min-height:40px;padding:.4rem .85rem;border:2px solid var(--ink);border-radius:var(--r);font-size:.9rem;text-decoration:none;white-space:nowrap;transition:background .18s,color .18s}
.strip a:hover,.strip a.on{background:var(--ink);color:var(--paper)}

/* hero */
.hero{display:grid;grid-template-columns:1.02fr .98fr;gap:clamp(1.5rem,4vw,3.5rem);align-items:center;min-height:70vh;padding:clamp(1.8rem,5vw,4rem) var(--gutter);border-bottom:2px solid var(--ink)}
.hero-media{aspect-ratio:4/3;border:2px solid var(--ink);border-radius:var(--r);overflow:hidden;background:var(--paper)}
.hero-media img{display:block;width:100%;height:100%;object-fit:cover;filter:grayscale(1) contrast(1.08)}
.hero-copy{text-align:center}
.hero h1{margin:0 0 1.1rem;font-size:clamp(2.7rem,8.5vw,6.5rem);font-weight:700;line-height:.94;letter-spacing:-.06em;overflow-wrap:anywhere}
.lede{max-width:32ch;margin:0 auto;font-size:clamp(1rem,1.6vw,1.12rem);opacity:.72}

.slant{height:clamp(44px,9vw,110px);margin:0 -4vw;background:var(--ink);transform:skewY(-3.2deg)}

/* layout */
.layout{display:grid;grid-template-columns:minmax(0,1fr) clamp(220px,23vw,290px);align-items:start;gap:clamp(1.4rem,4vw,3rem);padding:clamp(2rem,5vw,3.6rem) var(--gutter) clamp(3rem,7vw,5rem)}
.prose{min-width:0;max-width:70ch}
.prose>div{scroll-margin-top:152px}
.prose>div+div{margin-top:clamp(2.4rem,6vw,4.5rem);padding-top:clamp(1.8rem,4vw,3rem);border-top:2px solid var(--ink)}
.prose h2{margin:0 0 1rem;font-size:clamp(1.7rem,4.2vw,2.9rem);line-height:1.06;letter-spacing:-.05em}
.prose h3{margin:1.6rem 0 .6rem;font-size:1.2rem;letter-spacing:-.02em}
.prose p{margin:0 0 1.05rem}
.prose ul,.prose ol{margin:0 0 1.1rem;padding-left:1.35rem}
.prose li{margin:.32rem 0}
.prose a{text-decoration:underline;text-decoration-thickness:2px;text-underline-offset:3px}
.prose a:hover{background:var(--ink);color:var(--paper)}
.prose strong{font-weight:700}
.prose blockquote{margin:1.4rem 0;padding:.9rem 1.1rem;border-left:4px solid var(--ink);background:rgba(0,0,0,.04)}
.prose table{width:100%;margin:1.2rem 0;border-collapse:collapse;font-size:.95rem}
.prose th,.prose td{padding:.55rem .7rem;border:2px solid var(--ink);text-align:left;vertical-align:top}
.prose img{border:2px solid var(--ink);border-radius:var(--r)}
.prose code{padding:.1em .3em;border-radius:6px;background:rgba(0,0,0,.06);font-size:.95em}

/* rail */
.rail{position:sticky;top:calc(var(--topbar) + 14px);align-self:start;padding:1.1rem;border:2px solid var(--ink);border-radius:var(--r);background:var(--paper)}
.rail-h{margin:0 0 .2rem;font-size:1.05rem;letter-spacing:-.04em}
.subtitle{margin:0 0 .9rem;font-size:.82rem;letter-spacing:.14em;opacity:.6}
.rail ul{display:grid;gap:.15rem;margin:0;padding:0;list-style:none}
.rail a{display:flex;align-items:center;min-height:40px;padding:.35rem .5rem;border-bottom:1px solid rgba(0,0,0,.12);font-size:.9rem;text-decoration:none;transition:background .16s,color .16s,padding-left .16s}
.rail a:hover{background:var(--ink);color:var(--paper);padding-left:.8rem}
.to-top{display:inline-flex;align-items:center;min-height:40px;margin-top:.7rem;font-size:.85rem;text-decoration:underline;text-underline-offset:3px}

/* sheet menu */
.sheet{position:fixed;inset:0;z-index:120;display:flex;flex-direction:column;overflow-y:auto;padding:clamp(1rem,4vw,2.5rem) var(--gutter);background:var(--ink);color:var(--paper);transform:translateX(102%);visibility:hidden;transition:transform .45s cubic-bezier(.22,1,.36,1),visibility .45s}
body.menu-open .sheet{transform:none;visibility:visible}
body.menu-open{overflow:hidden}
.sheet-head{display:flex;align-items:center;justify-content:space-between;gap:1rem;padding-bottom:.8rem;border-bottom:2px solid var(--paper)}
.brand-inv{color:var(--paper)}
.sheet-close{min-height:44px;padding:.5rem 1rem;border:2px solid var(--paper);border-radius:var(--r);background:transparent;color:var(--paper);font-family:inherit;font-size:.9rem;cursor:pointer;transition:background .18s,color .18s}
.sheet-close:hover{background:var(--paper);color:var(--ink)}
.sheet nav{margin:auto 0;padding:1.5rem 0}
.sheet ul{margin:0;padding:0;list-style:none}
.sheet a{display:flex;align-items:center;min-height:56px;padding:.6rem 0;border-bottom:1px solid rgba(255,255,255,.16);color:var(--paper);font-size:clamp(1.5rem,5.5vw,2.8rem);font-weight:700;line-height:1.1;letter-spacing:-.05em;text-decoration:none;transition:padding-left .2s}
.sheet a:hover{padding-left:.7rem}

/* footer */
.foot{padding:clamp(2rem,5vw,3.6rem) var(--gutter) 1.4rem;border-top:3px solid var(--ink)}
.foot-cta{display:flex;flex-wrap:wrap;align-items:flex-end;justify-content:space-between;gap:1.2rem;padding-bottom:clamp(1.4rem,4vw,2.6rem);border-bottom:2px solid var(--ink)}
.cta-big{margin:0;font-size:clamp(2.4rem,11vw,7rem);font-weight:700;line-height:.88;letter-spacing:-.07em}
.foot-cols{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:clamp(1rem,3vw,2.5rem);padding:clamp(1.4rem,4vw,2.4rem) 0}
.foot dl{margin:0}
.foot dt{margin-bottom:.5rem;font-size:.78rem;letter-spacing:.2em;opacity:.55}
.foot dd{margin:0;font-size:.95rem}
.foot dd a{display:flex;align-items:center;min-height:40px;border-bottom:1px solid rgba(0,0,0,.12);text-decoration:none}
.foot dd a:hover{background:var(--ink);color:var(--paper);padding-left:.4rem}
.foot-base{display:flex;flex-wrap:wrap;align-items:center;justify-content:space-between;gap:1rem;padding-top:1rem;border-top:2px solid var(--ink);font-size:.85rem}
.foot-base p{margin:0}
.foot-base a{display:inline-flex;align-items:center;min-height:40px;text-decoration:underline;text-underline-offset:3px}

/* reveal */
.js .rv{opacity:0;transform:translateY(18px)}
.js .rv.in{opacity:1;transform:none;transition:opacity .55s ease,transform .55s ease}

@media (max-width:900px){
.layout{grid-template-columns:minmax(0,1fr)}
.prose{order:1}
.rail{order:2;position:static}
}

@media (max-width:820px){
.hero{grid-template-columns:minmax(0,1fr);min-height:0;padding-top:1.6rem}
.hero-copy{order:-1}
.foot-cols{grid-template-columns:repeat(2,minmax(0,1fr))}
}

@media (max-width:520px){
body{font-size:16px}
.masthead{padding:.6rem 1rem}
.strip ul{padding:.5rem 1rem}
.hero{padding:1.4rem 1rem 2rem}
.layout{padding-left:1rem;padding-right:1rem}
.foot{padding-left:1rem;padding-right:1rem}
.foot-cols{grid-template-columns:minmax(0,1fr)}
}

@media (prefers-reduced-motion:reduce){
html{scroll-behavior:auto}
.js .rv{opacity:1;transform:none;transition:none}
*{transition-duration:.01ms !important;animation-duration:.01ms !important}
}

button[aria-expanded]{min-width:44px;min-height:44px}