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

:root {
  --ink: #000000;
  --paper: #ffffff;
  --line: rgba(0, 0, 0, 0.16);
  --glass: rgba(255, 255, 255, 0.66);
  --r: 28px;
}

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

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

body {
  margin: 0;
  font-family: "Nunito Sans", system-ui, -apple-system, "PingFang SC", "Microsoft YaHei", sans-serif;
  font-size: 17px;
  line-height: 1.72;
  color: var(--ink);
  background-color: var(--paper);
  background-image: radial-gradient(rgba(0, 0, 0, 0.12) 1px, transparent 1px);
  background-size: 26px 26px;
}

h1,
h2,
h3,
.brand,
.cta {
  font-family: "Varela Round", "Nunito Sans", system-ui, sans-serif;
  font-weight: 400;
}

a {
  text-underline-offset: 3px;
}

/* 左侧固定竖排导航 */
.rail {
  position: fixed;
  top: 0;
  left: 0;
  bottom: 0;
  width: 264px;
  z-index: 40;
  display: flex;
  flex-direction: column;
  gap: 1.2rem;
  padding: 2rem 1.4rem;
  border-right: 1px solid var(--line);
  background: rgba(255, 255, 255, 0.76);
  -webkit-backdrop-filter: blur(16px);
  backdrop-filter: blur(16px);
  overflow-y: auto;
}

.brand {
  display: flex;
  align-items: center;
  gap: 0.7rem;
  min-height: 46px;
  color: var(--ink);
  text-decoration: none;
  font-size: 1.16rem;
  letter-spacing: -0.02em;
}

.mark {
  width: 40px;
  height: 40px;
  border-radius: 14px;
  object-fit: cover;
  display: block;
  flex: 0 0 auto;
}

.mark-dot {
  width: 22px;
  height: 22px;
  border-radius: 50%;
  background: var(--ink);
  flex: 0 0 auto;
}

.rail-list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: flex;
  flex-direction: column;
  gap: 0.15rem;
}

.rail-list a {
  display: flex;
  align-items: center;
  gap: 0.62rem;
  min-height: 44px;
  padding: 0.45rem 0.72rem;
  border-radius: 14px;
  color: var(--ink);
  text-decoration: none;
  font-size: 0.97rem;
  transition: background 0.25s ease, color 0.25s ease, transform 0.25s ease;
}

.rail-list a:hover,
.rail-list a.on {
  background: var(--ink);
  color: var(--paper);
  transform: translateX(2px);
}

.ico {
  width: 12px;
  height: 12px;
  flex: 0 0 auto;
}

.cta {
  margin-top: auto;
  display: flex;
  align-items: center;
  justify-content: center;
  min-height: 50px;
  padding: 0.8rem 1rem;
  border-radius: 999px;
  background: var(--ink);
  color: var(--paper);
  text-decoration: none;
  font-size: 1rem;
  transition: transform 0.25s ease, opacity 0.25s ease;
}

.cta:hover {
  transform: translateY(-2px);
  opacity: 0.86;
}

main,
footer {
  margin-left: 264px;
}

/* 首屏 */
.hero {
  position: relative;
  min-height: 70vh;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 1.6rem;
  padding: 5rem 2rem 4.5rem;
  text-align: center;
  background-image: radial-gradient(rgba(0, 0, 0, 0.2) 1px, transparent 1px);
  background-size: 18px 18px;
}

.hero h1 {
  margin: 0;
  max-width: 16ch;
  font-size: clamp(2.6rem, 8.5vw, 7rem);
  line-height: 0.98;
  letter-spacing: -0.05em;
}

.lede {
  margin: 0;
  max-width: 46ch;
  font-size: 1rem;
  opacity: 0.72;
}

.hero-art {
  margin: 0;
  width: clamp(84px, 12vw, 132px);
}

.hero-art svg {
  display: block;
  width: 100%;
  height: auto;
}

/* 正文区：左侧目录 + 玻璃卡片 */
.board {
  max-width: 1180px;
  margin: 0 auto 0 0;
  padding: 3.5rem 2.5rem 6rem;
  display: grid;
  grid-template-columns: 210px minmax(0, 1fr);
  gap: 2.4rem 3.4rem;
  align-items: start;
}

.board-aside {
  grid-column: 1;
  grid-row: 1;
  position: sticky;
  top: 1.6rem;
  padding: 1.2rem;
  border-radius: var(--r);
  border: 1px solid rgba(255, 255, 255, 0.75);
  background: var(--glass);
  -webkit-backdrop-filter: blur(14px);
  backdrop-filter: blur(14px);
  box-shadow: 0 18px 40px -28px rgba(0, 0, 0, 0.55);
}

.kicker {
  display: inline-block;
  font-size: 0.72rem;
  letter-spacing: 0.3em;
  opacity: 0.55;
}

.board-aside h2 {
  margin: 0.35rem 0 0.9rem;
  font-size: 1.34rem;
  line-height: 1.2;
  letter-spacing: -0.02em;
}

.aside-nav ul {
  list-style: none;
  margin: 0;
  padding: 0;
}

.aside-nav a {
  display: flex;
  align-items: center;
  min-height: 44px;
  padding: 0.4rem 0.1rem;
  font-size: 0.93rem;
  color: var(--ink);
  text-decoration: none;
  border-bottom: 1px solid rgba(0, 0, 0, 0.1);
}

.aside-nav li:last-child a {
  border-bottom: 0;
}

.aside-nav a:hover,
.aside-nav a.on {
  opacity: 0.5;
}

.board > section {
  grid-column: 2;
  scroll-margin-top: 5.5rem;
  padding: 2rem 2.2rem 2.3rem;
  border-radius: var(--r);
  border: 1px solid rgba(255, 255, 255, 0.8);
  background: var(--glass);
  -webkit-backdrop-filter: blur(12px);
  backdrop-filter: blur(12px);
  box-shadow: 0 24px 60px -46px rgba(0, 0, 0, 0.75);
}

.board > section h2 {
  margin: 0 0 1rem;
  font-size: clamp(1.6rem, 3.4vw, 2.5rem);
  line-height: 1.06;
  letter-spacing: -0.04em;
}

.board > section h3 {
  margin: 1.8rem 0 0.55rem;
  font-size: clamp(1.2rem, 2.2vw, 1.5rem);
  line-height: 1.25;
  letter-spacing: -0.02em;
}

.board > section p {
  margin: 0 0 1rem;
  max-width: 62ch;
}

.board > section p:last-child {
  margin-bottom: 0;
}

.board > section ul,
.board > section ol {
  max-width: 62ch;
  padding-left: 1.35rem;
}

.board > section li {
  margin: 0.35rem 0;
}

.board > section a {
  color: var(--ink);
}

.board > section img {
  max-width: 100%;
  height: auto;
  border-radius: 18px;
}

.board > section blockquote {
  margin: 1.4rem 0;
  padding: 0.2rem 0 0.2rem 1.2rem;
  border-left: 3px solid var(--ink);
  font-size: 1.04rem;
}

/* 页脚 */
footer {
  padding: 3rem 2.5rem 2rem;
  color: var(--paper);
  background-color: var(--ink);
  background-image: radial-gradient(rgba(255, 255, 255, 0.18) 1px, transparent 1px);
  background-size: 24px 24px;
}

.foot-cols {
  max-width: 1180px;
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 2rem;
}

footer address {
  font-style: normal;
  font-family: "Varela Round", system-ui, sans-serif;
  font-size: 1.45rem;
  line-height: 1.18;
  letter-spacing: -0.03em;
}

footer dl {
  margin: 0;
}

footer dt {
  margin-bottom: 0.25rem;
  font-size: 0.72rem;
  letter-spacing: 0.3em;
  opacity: 0.6;
}

footer dd {
  margin: 0;
}

footer dd a,
.foot-ul a {
  display: inline-flex;
  align-items: center;
  min-height: 42px;
  padding: 0.25rem 0;
  color: var(--paper);
  text-decoration: none;
  opacity: 0.86;
}

footer dd a:hover,
.foot-ul a:hover {
  opacity: 1;
  text-decoration: underline;
}

.foot-ul {
  list-style: none;
  margin: 0;
  padding: 0;
}

.foot-base {
  max-width: 1180px;
  margin: 2rem auto 0;
  padding-top: 1.2rem;
  border-top: 1px solid rgba(255, 255, 255, 0.32);
  text-align: center;
}

.foot-base p {
  margin: 0;
  font-size: 0.9rem;
}

.foot-base small {
  font-size: 0.78rem;
  opacity: 0.62;
}

/* 入场 */
html.js .reveal {
  opacity: 0;
  transform: translateY(16px);
  transition: opacity 0.6s ease, transform 0.6s ease;
}

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

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

@media (max-width: 1000px) {
  .rail {
    position: sticky;
    top: 0;
    bottom: auto;
    width: auto;
    flex-direction: row;
    align-items: center;
    gap: 0.5rem;
    padding: 0.6rem 1rem;
    border-right: 0;
    border-bottom: 1px solid var(--line);
    overflow-x: auto;
  }

  .brand {
    flex: 0 0 auto;
    font-size: 1rem;
    min-height: 44px;
  }

  .rail-list {
    flex-direction: row;
    gap: 0.2rem;
  }

  .rail-list a {
    white-space: nowrap;
    font-size: 0.9rem;
    padding: 0.4rem 0.62rem;
  }

  .rail-list a:hover,
  .rail-list a.on {
    transform: none;
  }

  .cta {
    flex: 0 0 auto;
    margin: 0 0 0 auto;
    min-height: 44px;
    padding: 0.45rem 1rem;
    font-size: 0.9rem;
  }

  main,
  footer {
    margin-left: 0;
  }

  .hero {
    min-height: auto;
    padding: 3.2rem 1.2rem 3rem;
  }

  .hero h1 {
    font-size: clamp(2.3rem, 10vw, 3.4rem);
  }

  .hero-art {
    order: 2;
    width: 84px;
  }

  .board {
    grid-template-columns: 1fr;
    gap: 1.2rem;
    padding: 2rem 1.1rem 3.5rem;
  }

  .board-aside {
    grid-column: 1;
    grid-row: auto;
    position: static;
  }

  .board-aside h2 {
    margin-bottom: 0.6rem;
    font-size: 1.1rem;
  }

  .aside-nav ul {
    display: flex;
    flex-wrap: wrap;
    gap: 0.4rem;
  }

  .aside-nav a {
    min-height: 40px;
    padding: 0.35rem 0.8rem;
    font-size: 0.85rem;
    border: 1px solid rgba(0, 0, 0, 0.18);
    border-radius: 999px;
  }

  .board > section {
    grid-column: 1;
    padding: 1.5rem 1.2rem 1.8rem;
    scroll-margin-top: 4.5rem;
  }

  .foot-cols {
    grid-template-columns: 1fr;
    gap: 1.6rem;
  }

  footer {
    padding: 2.4rem 1.1rem 1.6rem;
  }
}

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