@import url('https://fonts.googleapis.com/css2?family=Outfit:wght@300;400;500;600;700&family=Work+Sans:wght@300;400;500;600;700&display=swap');

:root {
  --fg: #000000;
  --bg: #ffffff;
  --r: 10px;
  --max: 1200px;
}

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

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

body {
  margin: 0;
  background: var(--bg);
  color: var(--fg);
  font-family: 'Outfit', 'Work Sans', system-ui, -apple-system, 'Segoe UI', 'Noto Sans SC', 'PingFang SC', sans-serif;
  font-size: 1.0625rem;
  line-height: 1.75;
  font-weight: 400;
  overflow-x: hidden;
}

img { max-width: 100%; height: auto; display: block; }

a { color: inherit; }

::selection { background: #000; color: #fff; }

:focus-visible { outline: 3px solid #000; outline-offset: 3px; }

/* ---------- 顶栏 ---------- */
.top {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  max-width: var(--max);
  margin: 0 auto;
  padding: 1rem 1.5rem;
}

.mark {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 44px;
  min-width: 44px;
  padding-right: .5rem;
  font-size: 1.15rem;
  font-weight: 900;
  letter-spacing: -.045em;
  text-decoration: none;
  color: #000;
}

.mark img {
  width: 40px;
  height: 40px;
  border-radius: 50%;
  object-fit: cover;
  background: #000;
}

.nav { position: relative; }

.nav-d summary {
  list-style: none;
  display: inline-flex;
  align-items: center;
  gap: .55rem;
  min-height: 44px;
  padding: .35rem 1.15rem;
  border: 2px solid #000;
  border-radius: var(--r);
  font-weight: 700;
  letter-spacing: -.01em;
  cursor: pointer;
}

.nav-d summary::-webkit-details-marker { display: none; }

.nav-d summary::after {
  content: "+";
  font-weight: 700;
  line-height: 1;
}

.nav-d[open] summary::after { content: "\2013"; }

.nav-m {
  position: absolute;
  right: 0;
  top: calc(100% + .5rem);
  z-index: 50;
  margin: 0;
  padding: .5rem;
  min-width: min(260px, 78vw);
  list-style: none;
  background: #000;
  color: #fff;
  border-radius: var(--r);
  box-shadow: 0 14px 34px rgba(0, 0, 0, .28);
}

.nav-m li { list-style: none; }

.nav-m a {
  display: flex;
  align-items: center;
  min-height: 44px;
  padding: .35rem .85rem;
  border-radius: 8px;
  color: #fff;
  text-decoration: none;
  font-weight: 600;
}

.nav-m a:hover { background: rgba(255, 255, 255, .18); }

/* ---------- 粘性锚点条 ---------- */
.rail {
  position: sticky;
  top: 0;
  z-index: 30;
  background: #fff;
  border-top: 2px solid #000;
  border-bottom: 2px solid #000;
}

.rail ul {
  display: flex;
  gap: .15rem;
  overflow-x: auto;
  max-width: var(--max);
  margin: 0 auto;
  padding: 0 1rem;
  list-style: none;
  scrollbar-width: none;
}

.rail ul::-webkit-scrollbar { display: none; }

.rail a {
  display: inline-flex;
  align-items: center;
  min-height: 48px;
  padding: 0 .9rem;
  white-space: nowrap;
  text-decoration: none;
  font-weight: 600;
  font-size: 1rem;
}

.rail a:hover { background: #000; color: #fff; }

/* ---------- Hero ---------- */
.hero {
  position: relative;
  overflow: hidden;
  display: grid;
  grid-template-columns: 170px minmax(0, 1fr);
  align-items: center;
  gap: clamp(1rem, 4vw, 3rem);
  min-height: 45vh;
  max-width: var(--max);
  margin: 0 auto;
  padding: clamp(2rem, 5vw, 4rem) 1.5rem;
}

.hero-bg {
  position: absolute;
  left: -.05em;
  top: 6%;
  z-index: 0;
  font-size: clamp(3rem, 10vw, 12rem);
  font-weight: 900;
  letter-spacing: -.05em;
  line-height: .8;
  white-space: nowrap;
  color: #ececec;
  pointer-events: none;
  user-select: none;
  will-change: transform;
}

.hero-body {
  position: relative;
  z-index: 1;
  min-width: 0;
}

.hero h1 {
  margin: 0 0 1.5rem;
  font-size: clamp(2.2rem, 6.5vw, 5.5rem);
  font-weight: 900;
  letter-spacing: -.05em;
  line-height: .94;
  text-align: right;
}

.hero-lead {
  margin: 0 0 0 auto;
  max-width: 34ch;
  text-align: right;
  font-size: clamp(1rem, 1.6vw, 1.15rem);
  color: #222;
}

.hero-fig {
  position: relative;
  z-index: 1;
  order: -1;
  margin: 0;
}

.hero-img {
  width: 100%;
  border-radius: var(--r);
  background: #000;
}

.hero-shape {
  aspect-ratio: 1 / 1;
  border-radius: var(--r);
  background: #000;
}

/* ---------- 主体 ---------- */
.shell {
  display: grid;
  grid-template-columns: minmax(0, 1fr) 250px;
  gap: clamp(2rem, 5vw, 4rem);
  max-width: var(--max);
  margin: 0 auto;
  padding: clamp(3rem, 7vw, 6rem) 1.5rem;
}

.paper { min-width: 0; }

.paper article[id] { scroll-margin-top: 5.5rem; }

.paper article + article {
  margin-top: 6rem;
  padding-top: 3.5rem;
  border-top: 2px solid #000;
}

.paper h2 {
  margin: 0 0 1.4rem;
  font-size: clamp(1.7rem, 3.6vw, 2.9rem);
  font-weight: 900;
  letter-spacing: -.045em;
  line-height: 1.05;
}

.paper h3 {
  margin: 2.4rem 0 .9rem;
  font-size: clamp(1.3rem, 2.4vw, 1.9rem);
  font-weight: 800;
  letter-spacing: -.03em;
  line-height: 1.2;
}

.paper h2 > span,
.paper h3 > span { display: inline; }

.paper p { margin: 0 0 1.4rem; }

.paper a { text-underline-offset: .18em; }

.paper ul,
.paper ol { margin: 0 0 1.4rem; padding-left: 1.3rem; }

.paper li { margin: .3rem 0; }

.paper strong { font-weight: 800; }

.paper blockquote {
  margin: 2rem 0;
  padding: 0 0 0 1.4rem;
  border-left: 6px solid #000;
  font-weight: 600;
}

.paper hr {
  border: 0;
  border-top: 1px solid #000;
  margin: 3rem 0;
}

.paper table {
  width: 100%;
  border-collapse: collapse;
  margin: 0 0 1.5rem;
  font-size: 1rem;
}

.paper th,
.paper td {
  padding: .65rem .5rem;
  border-bottom: 1px solid #000;
  text-align: left;
}

/* ---------- 侧栏 ---------- */
.side {
  position: sticky;
  top: 5rem;
  align-self: start;
  padding: 1.5rem 1.4rem;
  border-radius: var(--r);
  background: #000;
  color: #fff;
}

.side h2 {
  margin: 0 0 1rem;
  font-size: 1.05rem;
  font-weight: 900;
  letter-spacing: -.02em;
}

.side ol {
  margin: 0;
  padding: 0;
  list-style: none;
}

.side a {
  display: flex;
  align-items: center;
  min-height: 44px;
  padding: .35rem 0;
  color: #fff;
  text-decoration: none;
  border-top: 1px solid rgba(255, 255, 255, .28);
  font-size: 1rem;
}

.side li:first-child a { border-top: 0; }

.side a:hover { text-decoration: underline; }

/* ---------- 页脚 ---------- */
.foot {
  background: #000;
  color: #fff;
  padding: 5rem 1.5rem 2.5rem;
}

.foot-brand {
  margin: 0 0 3.5rem;
  font-size: clamp(2.5rem, 11vw, 8rem);
  font-weight: 900;
  letter-spacing: -.06em;
  line-height: .88;
}

.foot-cols {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 2rem;
  max-width: 900px;
}

.foot dl { margin: 0; }

.foot dt {
  margin-bottom: .5rem;
  font-weight: 700;
  letter-spacing: .02em;
}

.foot dd { margin: 0; }

.foot a {
  display: inline-flex;
  align-items: center;
  min-height: 44px;
  padding: .3rem 0;
  color: #fff;
  text-decoration: none;
}

.foot a:hover { text-decoration: underline; }

.foot-line {
  margin: 3rem 0 0;
  color: #b9b9b9;
  font-size: 1rem;
}

/* ---------- 入场 ---------- */
html.js .reveal {
  opacity: 0;
  transform: translateY(28px);
  transition: opacity .7s ease, transform .7s ease;
}

html.js .reveal.in {
  opacity: 1;
  transform: none;
}

/* ---------- 断点 ---------- */
@media (max-width: 900px) {
  .shell { grid-template-columns: minmax(0, 1fr); }
  .side { position: static; }
}

@media (max-width: 620px) {
  .top { padding: 1rem 1.1rem; }
  .hero {
    grid-template-columns: 1fr;
    min-height: 0;
    padding: 2rem 1.1rem 2.5rem;
  }
  .hero-fig { max-width: 110px; }
  .hero h1 { text-align: left; font-size: clamp(2rem, 9vw, 3rem); }
  .hero-lead { margin: 0; text-align: left; }
  .hero-bg {
    top: auto;
    bottom: .5rem;
    font-size: clamp(3rem, 19vw, 6rem);
  }
  .shell { padding: 2.5rem 1.1rem 4rem; }
  .paper article + article { margin-top: 4rem; padding-top: 2.5rem; }
  .foot { padding: 3.5rem 1.1rem 2rem; }
  .foot-brand { margin-bottom: 2.5rem; }
  .foot-cols { grid-template-columns: 1fr 1fr; gap: 1rem 1.5rem; }
}

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

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