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

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

:root {
  --ink: #000000;
  --paper: #ffffff;
  --gap: clamp(1.25rem, 4vw, 4.5rem);
  --ui: 'Atkinson Hyperlegible', system-ui, -apple-system, 'Segoe UI', 'PingFang SC', 'Microsoft YaHei', sans-serif;
  --text: 'Crimson Pro', Georgia, 'Songti SC', 'Times New Roman', serif;
}

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

body {
  margin: 0;
  background: var(--paper);
  color: var(--ink);
  font-family: var(--text);
  font-size: 1.125rem;
  line-height: 1.68;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}

img { max-width: 100%; }

h1, h2, h3 {
  font-family: var(--ui);
  font-weight: 700;
  letter-spacing: -0.045em;
  line-height: 0.98;
  margin: 0;
}

a { color: var(--ink); }

::selection { background: var(--ink); color: var(--paper); }

:focus-visible { outline: 3px solid var(--ink); outline-offset: 3px; }

/* 顶部 */
.masthead { border-bottom: 2px solid var(--ink); }

.util {
  display: flex;
  justify-content: flex-end;
  padding: 0.7rem var(--gap);
}

.seek { display: flex; gap: 0.4rem; margin-left: auto; }

.seek input {
  font-family: var(--ui);
  font-size: 1rem;
  padding: 0.55rem 0.8rem;
  min-height: 44px;
  width: 15rem;
  border: 1px solid var(--ink);
  border-radius: 0;
  background: var(--paper);
  color: var(--ink);
}

.seek button {
  font-family: var(--ui);
  font-size: 1rem;
  min-height: 44px;
  padding: 0 1.1rem;
  border: 1px solid var(--ink);
  border-radius: 0;
  background: var(--ink);
  color: var(--paper);
  cursor: pointer;
}

.seek button:hover { background: var(--paper); color: var(--ink); }

.dock {
  display: grid;
  grid-template-columns: 1fr auto 1fr;
  align-items: center;
  gap: 1rem;
  padding: 0.9rem var(--gap);
}

.brand {
  font-family: var(--ui);
  font-weight: 700;
  font-size: clamp(1.5rem, 3vw, 2.3rem);
  letter-spacing: -0.05em;
  text-decoration: none;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 44px;
  padding: 0 0.5rem;
  white-space: nowrap;
}

.dock-list {
  list-style: none;
  display: flex;
  flex-wrap: wrap;
  gap: 0.25rem 0.9rem;
  margin: 0;
  padding: 0;
}

.dock-left { justify-content: flex-end; }
.dock-right { justify-content: flex-start; }

.dock-list a {
  display: inline-flex;
  align-items: center;
  gap: 0.45rem;
  min-height: 44px;
  padding: 0.4rem 0.1rem;
  font-family: var(--ui);
  font-size: 1rem;
  text-decoration: none;
  border-bottom: 2px solid transparent;
}

.dock-list a:hover { border-bottom-color: var(--ink); }

.dot { width: 0.45rem; height: 0.45rem; background: var(--ink); flex: none; }

.dock-list li.is-off { display: none; }

/* 首屏 */
.hero {
  position: relative;
  grid-column: 1 / -1;
  margin: 0 calc(var(--gap) * -1);
  min-height: 100vh;
  min-height: 100svh;
  display: flex;
  align-items: flex-end;
  justify-content: flex-end;
  padding: clamp(2rem, 6vw, 5rem);
  padding-bottom: clamp(2.6rem, 7vw, 6rem);
  background: var(--ink);
  color: var(--paper);
  overflow: hidden;
  isolation: isolate;
}

.hero-media { position: absolute; inset: 0; z-index: 0; }

.hero-media img {
  display: block;
  width: 100%;
  height: 100%;
  object-fit: cover;
  filter: grayscale(1) contrast(1.08);
}

.hero::before {
  content: '';
  position: absolute;
  inset: 0;
  z-index: 1;
  background: linear-gradient(to top, rgba(0, 0, 0, 0.88), rgba(0, 0, 0, 0.2) 55%, rgba(0, 0, 0, 0.5));
}

.hero-band {
  position: absolute;
  left: 0;
  right: 0;
  bottom: 0;
  height: clamp(1.5rem, 4vw, 3.5rem);
  background: var(--paper);
  clip-path: polygon(0 100%, 100% 0, 100% 100%);
  z-index: 2;
}

.hero-copy { position: relative; z-index: 3; text-align: right; max-width: 100%; }

.hero-copy h1 {
  font-size: clamp(3rem, 10vw, 9rem);
  letter-spacing: -0.055em;
  line-height: 0.88;
  overflow-wrap: break-word;
  text-wrap: balance;
}

/* 版心 */
.piece {
  display: grid;
  grid-template-columns: minmax(0, 1fr) 21rem;
  column-gap: clamp(2rem, 5vw, 5rem);
  align-items: start;
  padding: 0 var(--gap);
}

.flow {
  min-width: 0;
  padding: clamp(2.5rem, 6vw, 5rem) 0 clamp(3rem, 7vw, 6rem);
  counter-reset: sec;
}

.flow > section {
  border-top: 2px solid var(--ink);
  padding: clamp(2rem, 4vw, 3.5rem) 0;
  scroll-margin-top: 1.5rem;
  counter-increment: sec;
}

.flow > section:first-child { border-top: 0; }

.flow > section::before {
  content: counter(sec, decimal-leading-zero);
  display: block;
  font-family: var(--ui);
  font-size: 1rem;
  letter-spacing: 0.16em;
  margin-bottom: 1.2rem;
}

.flow h2 {
  font-size: clamp(1.8rem, 4.4vw, 3.2rem);
  margin: 0 0 1.2rem;
}

.flow h3 {
  font-size: clamp(1.25rem, 2.4vw, 1.7rem);
  letter-spacing: -0.03em;
  margin: 2.2rem 0 0.6rem;
}

.flow p { max-width: 66ch; margin: 0 0 1.3rem; }

.flow ul, .flow ol { max-width: 66ch; padding-left: 1.3rem; margin: 0 0 1.4rem; }

.flow li { margin-bottom: 0.5rem; }

.flow blockquote {
  margin: 1.8rem 0;
  padding: 0.4rem 0 0.4rem 1.4rem;
  border-left: 8px solid var(--ink);
  font-size: 1.3rem;
  line-height: 1.45;
}

.flow strong { font-weight: 700; }

.flow img { margin: 1.5rem 0; height: auto; border: 2px solid var(--ink); }

.flow hr { border: 0; border-top: 2px solid var(--ink); margin: 2rem 0; }

.flow a { text-decoration: underline; text-underline-offset: 0.2em; }

.js-reveal { opacity: 0; transform: translateY(20px); transition: opacity 0.7s ease, transform 0.7s ease; }
.js-reveal.in { opacity: 1; transform: none; }

/* 侧栏 */
.rail {
  position: sticky;
  top: 2rem;
  align-self: start;
  margin: clamp(2.5rem, 6vw, 5rem) 0 4rem;
  border-top: 6px solid var(--ink);
  padding-top: 1.1rem;
  font-family: var(--ui);
}

.rail h2 { font-size: 1.4rem; }

.rail .subtitle {
  font-family: var(--text);
  font-size: 1rem;
  line-height: 1.55;
  margin: 0.6rem 0 1.2rem;
}

.rail-list {
  list-style: none;
  margin: 0;
  padding: 0;
  counter-reset: rail;
  border-top: 1px solid var(--ink);
}

.rail-list li { counter-increment: rail; border-bottom: 1px solid var(--ink); }

.rail-list a {
  display: flex;
  align-items: center;
  gap: 0.7rem;
  min-height: 44px;
  padding: 0.35rem 0;
  font-size: 1rem;
  text-decoration: none;
}

.rail-list a::before {
  content: counter(rail, decimal-leading-zero);
  font-size: 0.95rem;
  letter-spacing: 0.1em;
  flex: none;
}

.rail-list a:hover { background: var(--ink); color: var(--paper); }

/* 页脚 */
footer {
  display: grid;
  grid-template-columns: 1fr auto 1fr;
  align-items: center;
  gap: 1rem;
  border-top: 2px solid var(--ink);
  padding: 1.4rem var(--gap);
  font-family: var(--ui);
  font-size: 1rem;
}

footer p { margin: 0; }
footer section { min-width: 0; }
.f-brand p { font-weight: 700; letter-spacing: -0.03em; }
.f-copy { text-align: center; }
.f-top { text-align: right; }
.f-top a {
  display: inline-flex;
  align-items: center;
  min-height: 44px;
  text-decoration: none;
  border-bottom: 2px solid transparent;
}
.f-top a:hover { border-bottom-color: var(--ink); }

@media (max-width: 1024px) {
  .piece { grid-template-columns: minmax(0, 1fr); }
  .rail { position: static; margin: 0 0 3.5rem; }
}

@media (max-width: 860px) {
  .util { padding: 0.6rem var(--gap); }
  .seek { width: 100%; }
  .seek input { width: 100%; flex: 1 1 auto; }
  .dock {
    grid-template-columns: 1fr;
    justify-items: center;
    gap: 0.4rem;
    padding: 0.6rem var(--gap) 1rem;
  }
  .brand { order: -1; font-size: clamp(1.6rem, 7vw, 2.1rem); }
  .dock-list { justify-content: center; gap: 0.15rem 0.6rem; }
  .dock-list a { font-size: 1rem; padding: 0.35rem 0.2rem; }
  .hero {
    min-height: 62vh;
    min-height: 62svh;
    padding: 1.6rem 1.4rem 2.6rem;
  }
  .hero-copy h1 { font-size: clamp(2.4rem, 12.5vw, 4rem); }
  footer {
    grid-template-columns: 1fr;
    justify-items: center;
    text-align: center;
    gap: 0.3rem;
    padding: 1.2rem var(--gap);
  }
  .f-top { text-align: center; }
}

@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}