@import url('https://fonts.googleapis.com/css2?family=Space+Grotesk:wght@400;500;600;700&display=swap');

:root{
--ink:#000000;
--paper:#ffffff;
--rule:#000000;
--soft:#e3e3e3;
--mute:#2b2b2b;
--pad:clamp(16px,4vw,48px);
--max:1280px;
--u:8px;
}

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

html{
-webkit-text-size-adjust:100%;
scroll-behavior:smooth;
}

body{
margin:0;
overflow-x:hidden;
background:var(--paper);
color:var(--ink);
font-family:"Space Grotesk","Helvetica Neue",Helvetica,Arial,"Noto Sans SC","PingFang SC","Microsoft YaHei",sans-serif;
font-size:17px;
line-height:1.65;
font-weight:400;
}

img{display:block;max-width:100%;height:auto}
a{color:inherit}
p{margin:0 0 1rem}
:focus-visible{outline:2px solid var(--ink);outline-offset:3px}

/* ---------- 顶部细条 ---------- */
.strip{background:var(--ink);color:var(--paper)}
.strip-in{
display:flex;
align-items:center;
justify-content:space-between;
gap:16px;
max-width:var(--max);
margin:0 auto;
padding:0 var(--pad);
min-height:40px;
}
.dots{display:inline-flex;gap:6px;align-items:center;height:40px}
.dots span{width:8px;height:8px;background:var(--paper);display:block}
.strip-top{
display:inline-flex;
align-items:center;
min-height:40px;
padding:0 2px;
color:var(--paper);
text-decoration:none;
font-size:16px;
letter-spacing:.06em;
}
.strip-top:hover{text-decoration:underline;text-underline-offset:4px}

/* ---------- 主导航 ---------- */
.bar{
display:grid;
grid-template-columns:1fr auto 1fr;
align-items:center;
gap:16px;
max-width:var(--max);
margin:0 auto;
padding:14px var(--pad);
border-bottom:2px solid var(--rule);
}
.group{position:relative}
.group--l{justify-self:start}
.group--r{justify-self:end}
.group summary{
list-style:none;
display:inline-flex;
align-items:center;
gap:10px;
min-height:44px;
padding:10px 16px;
border:1px solid var(--rule);
font-size:16px;
font-weight:600;
letter-spacing:.1em;
cursor:pointer;
-webkit-user-select:none;
user-select:none;
}
.group summary::-webkit-details-marker{display:none}
.group summary::after{
content:"";
width:8px;
height:8px;
background:var(--ink);
transition:transform .18s ease;
}
.group[open] summary{background:var(--ink);color:var(--paper)}
.group[open] summary::after{background:var(--paper);transform:rotate(45deg)}
.group menu{
list-style:none;
position:absolute;
top:calc(100% + 8px);
left:0;
z-index:40;
min-width:min(240px,78vw);
margin:0;
padding:6px;
background:var(--ink);
color:var(--paper);
border-radius:4px;
box-shadow:0 14px 30px rgba(0,0,0,.24);
}
.group--r menu{left:auto;right:0}
.group menu a{
display:flex;
align-items:center;
min-height:44px;
padding:8px 12px;
color:var(--paper);
text-decoration:none;
font-size:16px;
border-bottom:1px solid rgba(255,255,255,.3);
}
.group menu li:last-child a{border-bottom:0}
.group menu a:hover,
.group menu a:focus-visible{background:var(--paper);color:var(--ink)}

.mark{
justify-self:center;
display:inline-flex;
align-items:center;
min-height:44px;
padding:10px 8px;
font-size:clamp(18px,2.2vw,26px);
font-weight:700;
letter-spacing:-.02em;
text-decoration:none;
white-space:nowrap;
}
.mark:hover{text-decoration:underline;text-underline-offset:6px;text-decoration-thickness:3px}

/* ---------- 首屏 ---------- */
.hero{
display:grid;
grid-template-columns:repeat(12,1fr);
align-items:center;
gap:16px;
min-height:45vh;
padding:clamp(28px,6vw,64px) var(--pad);
border-bottom:2px solid var(--rule);
background-color:var(--paper);
background-image:radial-gradient(var(--ink) 1px,transparent 1px);
background-size:16px 16px;
}
.hero-media{
grid-column:4 / span 2;
display:flex;
justify-content:flex-end;
}
.hero-art{
width:clamp(64px,9vw,120px);
filter:grayscale(1);
}
.hero-txt{
grid-column:6 / span 7;
text-align:right;
}
.hero-txt h1{
margin:0;
font-size:clamp(30px,6.2vw,74px);
line-height:1.04;
letter-spacing:-.035em;
font-weight:700;
}

/* ---------- 正文骨架 ---------- */
.wrap{
display:grid;
grid-template-columns:minmax(0,1fr) 264px;
gap:clamp(24px,4vw,56px);
max-width:var(--max);
margin:0 auto;
padding:clamp(28px,5vw,56px) var(--pad) 0;
}
.stream{min-width:0}

.prose > div{
padding:clamp(24px,4vw,44px) 0;
border-top:1px solid var(--rule);
scroll-margin-top:24px;
}
.prose > div:first-child{border-top:0;padding-top:0}
.prose h2{
position:relative;
margin:0 0 .5rem;
padding-left:24px;
font-size:clamp(22px,3.2vw,32px);
line-height:1.16;
letter-spacing:-.02em;
font-weight:700;
}
.prose h2::before{
content:"";
position:absolute;
left:0;
top:.5em;
width:12px;
height:12px;
background:var(--ink);
}
.prose h3{
margin:1.6rem 0 .4rem;
font-size:clamp(18px,2.2vw,22px);
line-height:1.3;
letter-spacing:-.01em;
}
.prose p,
.prose ul,
.prose ol,
.prose blockquote{max-width:70ch}
.prose ul,
.prose ol{padding-left:1.2em;margin:0 0 1rem}
.prose li{margin:0 0 .45rem}
.prose a{text-decoration:underline;text-underline-offset:3px;text-decoration-thickness:2px}
.prose strong{font-weight:700}
.prose blockquote{
margin:1.2rem 0;
padding:.2rem 0 .2rem 20px;
border-left:4px solid var(--ink);
font-size:17px;
}
.prose .subtitle,
.prose p.subtitle,
.prose p.subhead,
.prose p.lead,
.prose p.desc{
max-width:70ch;
font-size:16px;
color:var(--mute);
letter-spacing:.01em;
margin:0 0 1.1rem;
}
.prose img{margin:1rem 0}
.prose table{width:100%;border-collapse:collapse;margin:1rem 0;font-size:16px}
.prose th,
.prose td{border-bottom:1px solid var(--rule);padding:10px 8px;text-align:left;vertical-align:top}

/* ---------- 侧栏 ---------- */
.rail{
align-self:start;
position:sticky;
top:20px;
border-left:1px solid var(--rule);
padding-left:20px;
}
.rail-h{
margin:0;
font-size:20px;
font-weight:700;
letter-spacing:.2em;
line-height:1.3;
}
.rail .subtitle{
margin:.35rem 0 1.1rem;
padding-bottom:.7rem;
border-bottom:2px solid var(--rule);
font-size:16px;
font-weight:500;
letter-spacing:.06em;
}
.rail-menu{list-style:none;margin:0;padding:0}
.rail-menu a{
display:block;
min-height:44px;
padding:10px 0;
font-size:16px;
text-decoration:none;
border-bottom:1px solid var(--soft);
}
.rail-menu a:hover,
.rail-menu a:focus-visible{
background:var(--ink);
color:var(--paper);
padding-left:8px;
}

/* ---------- 页脚 ---------- */
.foot{
display:grid;
grid-template-columns:1fr 1fr;
align-items:center;
gap:8px 16px;
margin-top:clamp(28px,5vw,64px);
padding:12px var(--pad);
border-top:2px solid var(--rule);
}
.foot p{margin:0;font-size:16px}
.foot-b{justify-self:end}
.foot menu{
list-style:none;
display:flex;
flex-wrap:wrap;
gap:2px 18px;
justify-content:flex-end;
margin:0;
padding:0;
}
.foot a{
display:inline-flex;
align-items:center;
min-height:40px;
padding:2px 0;
font-size:16px;
text-decoration:none;
}
.foot a:hover{text-decoration:underline;text-underline-offset:4px;text-decoration-thickness:2px}

/* ---------- 动效 ---------- */
.js .reveal{
opacity:0;
transform:translateY(14px);
transition:opacity .55s ease,transform .55s ease;
}
.js .reveal.is-in{opacity:1;transform:none}

/* ---------- 移动端 ---------- */
@media (max-width:860px){
.bar{
grid-template-columns:1fr 1fr;
gap:10px;
}
.mark{grid-column:1 / -1;order:-1;justify-self:center}
.group--l{justify-self:start}
.group--r{justify-self:end}
.group summary{padding:10px 14px}
.hero{
grid-template-columns:1fr;
min-height:auto;
gap:20px;
padding:clamp(24px,7vw,40px) var(--pad) clamp(28px,8vw,44px);
}
.hero-media{grid-column:1;justify-content:flex-end}
.hero-txt{grid-column:1}
.hero-txt h1{font-size:clamp(30px,9vw,46px)}
.wrap{
grid-template-columns:minmax(0,1fr);
gap:28px;
}
.rail{
position:static;
border-left:0;
border-top:2px solid var(--rule);
padding-left:0;
padding-top:16px;
}
.foot{
grid-template-columns:1fr;
gap:0;
}
.foot-b{justify-self:start}
.foot menu{justify-content:flex-start}
}

@media (prefers-reduced-motion:reduce){
html{scroll-behavior:auto}
.js .reveal{opacity:1;transform:none;transition:none}
}

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