@import url('https://fonts.googleapis.com/css2?family=Abril+Fatface&family=Merriweather:wght@300;400;700&display=swap');

:root {
  --ink: #1f1f1f;
  --ink-soft: #4a4a4a;
  --ink-mute: #6d6d6d;
  --paper: #ffffff;
  --paper-2: #f5f5f5;
  --line: rgba(31, 31, 31, .12);
  --r: 18px;
  --serif: 'Abril Fatface', "Songti SC", "Noto Serif SC", Georgia, serif;
  --body: 'Merriweather', "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", system-ui, -apple-system, sans-serif;
  --e1: 0 1px 2px rgba(31, 31, 31, .06), 0 2px 6px rgba(31, 31, 31, .05);
  --e2: 0 2px 6px rgba(31, 31, 31, .07), 0 10px 22px rgba(31, 31, 31, .07);
  --e3: 0 6px 14px rgba(31, 31, 31, .09), 0 20px 40px rgba(31, 31, 31, .10);
  --e4: 0 12px 26px rgba(31, 31, 31, .12), 0 34px 64px rgba(31, 31, 31, .16);
}

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

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

body {
  margin: 0;
  font-family: var(--body);
  font-size: 17px;
  line-height: 1.78;
  color: var(--ink);
  background: var(--paper-2);
  overflow-x: clip;
}

img { display: block; max-width: 100%; }
a { color: inherit; }
p { margin: 0 0 1em; }

:focus-visible {
  outline: 3px solid var(--ink);
  outline-offset: 3px;
  border-radius: 8px;
}

.skip {
  position: absolute;
  left: 12px;
  top: -70px;
  z-index: 90;
  display: inline-flex;
  align-items: center;
  min-height: 44px;
  padding: 0 16px;
  border-radius: 10px;
  background: var(--ink);
  color: #fff;
  text-decoration: none;
  box-shadow: var(--e3);
  transition: top .2s ease;
}
.skip:focus { top: 12px; }

/* ---------- 顶部层叠条 ---------- */
.rail {
  position: sticky;
  top: 0;
  z-index: 50;
  display: grid;
  grid-template-columns: auto 1fr auto;
  align-items: center;
  gap: 10px 18px;
  padding: 10px clamp(14px, 3vw, 34px);
  background: rgba(245, 245, 245, .84);
  border-bottom: 1px solid var(--line);
  box-shadow: var(--e1);
}
@supports (backdrop-filter: blur(2px)) {
  .rail { backdrop-filter: blur(14px) saturate(140%); }
}

.rail__brand { margin: 0; }
.rail__logo {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  min-height: 44px;
  padding: 0 6px;
  font-family: var(--serif);
  font-size: 19px;
  letter-spacing: .02em;
  text-decoration: none;
}
.rail__mark {
  width: 28px;
  height: 28px;
  border-radius: 8px;
  box-shadow: var(--e1);
}

.rail__nav { justify-self: center; min-width: 0; max-width: 100%; }
.rail__nav ul {
  display: flex;
  flex-wrap: wrap;
  gap: 2px;
  margin: 0;
  padding: 0;
  list-style: none;
}
.rail__nav a {
  display: inline-flex;
  align-items: center;
  gap: 7px;
  min-height: 44px;
  padding: 0 12px;
  border-radius: 999px;
  font-size: 16px;
  color: var(--ink-soft);
  text-decoration: none;
  transition: background .18s ease, color .18s ease, box-shadow .18s ease, transform .18s ease;
}
.rail__nav a:hover,
.rail__nav a:focus-visible {
  background: var(--paper);
  color: var(--ink);
  box-shadow: var(--e2);
  transform: translateY(-2px);
}
.rail__dot {
  width: 6px;
  height: 6px;
  border-radius: 50%;
  background: var(--ink);
  opacity: .34;
}

.rail__cta {
  display: inline-flex;
  align-items: center;
  min-height: 44px;
  padding: 0 18px;
  border-radius: 999px;
  background: var(--ink);
  color: #fff;
  font-size: 16px;
  text-decoration: none;
  box-shadow: var(--e3);
  transition: transform .18s ease, box-shadow .18s ease;
}
.rail__cta:hover { transform: translateY(-2px); box-shadow: var(--e4); }

/* ---------- 首屏 ---------- */
.hero {
  position: relative;
  isolation: isolate;
  overflow: hidden;
  display: grid;
  grid-template-columns: minmax(0, 1.08fr) minmax(0, .92fr);
  grid-template-areas: "copy art" "index art";
  align-content: start;
  gap: 26px 34px;
  min-height: 100vh;
  padding: clamp(26px, 4.5vw, 64px) clamp(18px, 4.5vw, 56px) clamp(44px, 7vw, 96px);
  background: var(--ink);
  color: #fff;
}
.hero::after {
  content: "";
  position: absolute;
  inset: auto 0 0 0;
  height: 90px;
  z-index: 1;
  background: linear-gradient(to bottom, rgba(31, 31, 31, 0), rgba(31, 31, 31, .55));
  pointer-events: none;
}

.hero__bg {
  position: absolute;
  top: 4%;
  left: -3%;
  z-index: 0;
  font-family: var(--serif);
  font-size: clamp(80px, 25vw, 300px);
  line-height: .78;
  letter-spacing: .01em;
  color: rgba(255, 255, 255, .06);
  white-space: nowrap;
  pointer-events: none;
  user-select: none;
  will-change: transform;
}

.hero__copy { grid-area: copy; position: relative; z-index: 3; }
.hero__copy h1 {
  margin: 0 0 18px;
  font-family: var(--serif);
  font-weight: 400;
  font-size: clamp(32px, 5.6vw, 68px);
  line-height: 1.08;
  letter-spacing: .01em;
}
.hero__desc {
  margin: 0;
  max-width: 36ch;
  font-size: 17px;
  line-height: 1.82;
  color: rgba(255, 255, 255, .74);
}

.hero__art {
  grid-area: art;
  position: relative;
  z-index: 2;
  margin: 0;
  min-height: clamp(240px, 34vw, 440px);
}
.hero__img {
  position: absolute;
  width: min(74%, 300px);
  aspect-ratio: 3 / 4;
  object-fit: cover;
  border: 7px solid var(--paper);
  border-radius: var(--r);
  box-shadow: var(--e4);
}
.hero__img--a { top: 0; left: 0; z-index: 3; transform: rotate(-4deg); }
.hero__img--b { right: 0; bottom: -4%; z-index: 2; transform: rotate(5deg); }

.hero__index {
  grid-area: index;
  position: relative;
  z-index: 4;
  max-width: 460px;
  margin-right: auto;
  padding: 16px 16px 18px;
  border-radius: var(--r);
  background: var(--paper);
  color: var(--ink);
  box-shadow: var(--e3);
}
.hero__index small {
  display: block;
  font-size: 16px;
  letter-spacing: .2em;
  color: var(--ink-mute);
}
.hero__index h2 {
  margin: 2px 0 12px;
  font-family: var(--serif);
  font-weight: 400;
  font-size: 24px;
  line-height: 1.2;
}
.hero__index ul {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin: 0;
  padding: 0;
  list-style: none;
}
.hero__index a {
  display: inline-flex;
  align-items: center;
  min-height: 40px;
  padding: 0 13px;
  border-radius: 999px;
  background: var(--paper-2);
  font-size: 16px;
  text-decoration: none;
  box-shadow: var(--e1);
  transition: transform .18s ease, box-shadow .18s ease, background .18s ease;
}
.hero__index a:hover {
  background: var(--paper);
  transform: translateY(-2px);
  box-shadow: var(--e2);
}

/* ---------- 正文层 ---------- */
.flow {
  position: relative;
  z-index: 2;
  max-width: 980px;
  margin: 0 auto;
  padding: clamp(30px, 5vw, 64px) clamp(14px, 4vw, 32px);
  display: grid;
  gap: clamp(24px, 4vw, 42px);
}
.flow > article {
  position: relative;
  padding: clamp(22px, 3.6vw, 40px);
  border-radius: var(--r);
  background: var(--paper);
  box-shadow: var(--e2);
  scroll-margin-top: 132px;
}
.flow > article:nth-child(odd) { transform: translateX(-5px); }
.flow > article:nth-child(even) { transform: translateX(6px); box-shadow: var(--e3); }

.flow small {
  display: block;
  margin-bottom: 4px;
  font-size: 16px;
  letter-spacing: .2em;
  color: var(--ink-mute);
}
.flow h2 {
  margin: 0 0 .55em;
  font-family: var(--serif);
  font-weight: 400;
  font-size: clamp(23px, 3vw, 32px);
  line-height: 1.22;
}
.flow h3 {
  margin: 1.2em 0 .45em;
  font-family: var(--serif);
  font-weight: 400;
  font-size: 20px;
  line-height: 1.32;
}
.flow p:last-child { margin-bottom: 0; }
.flow ul, .flow ol { margin: 0 0 1em; padding-left: 1.3em; }
.flow li { margin-bottom: .35em; }
.flow li:last-child { margin-bottom: 0; }
.flow a {
  text-decoration: underline;
  text-decoration-thickness: 2px;
  text-decoration-color: rgba(31, 31, 31, .28);
  text-underline-offset: 3px;
}
.flow a:hover { text-decoration-color: var(--ink); }
.flow img { border-radius: 14px; }
.flow figure { margin: 0 0 1.1em; }
.flow figure img { width: 100%; box-shadow: var(--e3); }
.flow figcaption { margin-top: 8px; font-size: 16px; color: var(--ink-mute); }
.flow aside {
  margin: 0 0 1em;
  padding: 16px 18px;
  border-radius: 14px;
  background: var(--paper-2);
  box-shadow: inset 0 0 0 1px var(--line);
}
.flow blockquote {
  margin: 0 0 1em;
  padding: 14px 18px;
  border-left: 4px solid var(--ink);
  border-radius: 0 14px 14px 0;
  background: var(--paper-2);
}

/* ---------- 收尾卡 ---------- */
.outro {
  position: relative;
  z-index: 2;
  display: flex;
  justify-content: center;
  padding: 0 clamp(14px, 4vw, 32px) clamp(40px, 6vw, 72px);
}
.outro__card {
  width: 100%;
  max-width: 520px;
  padding: clamp(22px, 3.6vw, 36px);
  border-radius: var(--r);
  background: var(--ink);
  color: #fff;
  text-align: center;
  box-shadow: var(--e4);
  transform: rotate(-1.2deg);
}
.outro__card small {
  display: block;
  font-size: 16px;
  letter-spacing: .2em;
  color: rgba(255, 255, 255, .6);
}
.outro__card h2 {
  margin: 4px 0 16px;
  font-family: var(--serif);
  font-weight: 400;
  font-size: clamp(24px, 3.4vw, 32px);
  line-height: 1.25;
}
.outro__btn {
  display: inline-flex;
  align-items: center;
  min-height: 44px;
  padding: 0 20px;
  border-radius: 999px;
  background: var(--paper);
  color: var(--ink);
  text-decoration: none;
  box-shadow: var(--e2);
  transition: transform .18s ease, box-shadow .18s ease;
}
.outro__btn:hover { transform: translateY(-2px); box-shadow: var(--e3); }

/* ---------- 页脚 ---------- */
.foot {
  position: relative;
  z-index: 1;
  display: grid;
  grid-template-columns: minmax(0, 1.5fr) minmax(0, 1fr);
  gap: 26px 32px;
  padding: clamp(30px, 5vw, 60px) clamp(16px, 4vw, 44px) 22px;
  background: var(--ink);
  color: #fff;
  box-shadow: 0 -18px 44px rgba(31, 31, 31, .18);
}
.foot__big {
  margin: 0;
  font-family: var(--serif);
  font-size: clamp(38px, 8.4vw, 116px);
  line-height: .86;
  color: rgba(255, 255, 255, .92);
  word-break: break-word;
}
.foot__nav ul {
  display: flex;
  flex-wrap: wrap;
  gap: 4px 16px;
  margin: 0;
  padding: 0;
  list-style: none;
}
.foot__nav a {
  display: inline-flex;
  align-items: center;
  min-height: 40px;
  font-size: 16px;
  color: rgba(255, 255, 255, .78);
  text-decoration: none;
}
.foot__nav a:hover { color: #fff; text-decoration: underline; }
.foot__meta {
  grid-column: 1 / -1;
  display: flex;
  flex-wrap: wrap;
  justify-content: space-between;
  align-items: center;
  gap: 10px;
  padding-top: 16px;
  border-top: 1px solid rgba(255, 255, 255, .16);
  font-size: 16px;
  color: rgba(255, 255, 255, .6);
}
.foot__meta p { margin: 0; }
.foot__meta a {
  display: inline-flex;
  align-items: center;
  min-height: 40px;
  padding: 0 4px;
  color: #fff;
  text-decoration: none;
}

/* ---------- 窄屏 ---------- */
@media (max-width: 820px) {
  .rail {
    grid-template-columns: auto auto;
    grid-template-areas: "brand cta" "nav nav";
    justify-content: space-between;
  }
  .rail__brand { grid-area: brand; }
  .rail__cta { grid-area: cta; }
  .rail__nav { grid-area: nav; justify-self: stretch; width: 100%; }
  .rail__nav ul {
    flex-wrap: nowrap;
    overflow-x: auto;
    padding-bottom: 4px;
    scrollbar-width: none;
  }
  .rail__nav ul::-webkit-scrollbar { display: none; }

  .hero {
    grid-template-columns: minmax(0, 1fr);
    grid-template-areas: "copy" "art" "index";
    min-height: 0;
    padding-bottom: clamp(30px, 6vw, 48px);
  }
  .hero__art { min-height: clamp(200px, 52vw, 300px); }
  .hero__img { width: min(58%, 240px); }
  .hero__img--b { bottom: -8%; }
  .hero::after { height: 50px; }

  .flow > article { transform: none; }
  .foot { grid-template-columns: minmax(0, 1fr); }
}

@media (max-width: 420px) {
  .rail__logo { font-size: 17px; }
  .hero__index { max-width: none; }
  .outro__card { transform: none; }
}

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  *, *::before, *::after {
    animation-duration: .001ms !important;
    transition-duration: .001ms !important;
  }
  .hero__bg { transform: none !important; }
}

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