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

:root {
  --ink: #000000;
  --paper: #ffffff;
  --wash: #f5f5f6;
  --line: rgba(0, 0, 0, 0.12);
  --line-soft: rgba(0, 0, 0, 0.07);
  --glass: rgba(255, 255, 255, 0.66);
  --r: 28px;
  --maxw: 1200px;
  --pad: clamp(16px, 4vw, 44px);
}

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

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

body {
  margin: 0;
  background: var(--wash);
  color: var(--ink);
  font-family: "Plus Jakarta Sans", system-ui, -apple-system, "PingFang SC",
    "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
  font-size: 17px;
  line-height: 1.7;
  letter-spacing: 0.005em;
  -webkit-font-smoothing: antialiased;
}

img,
svg {
  max-width: 100%;
}

a {
  color: inherit;
}

h1,
h2,
h3,
h4 {
  margin: 0;
  font-weight: 700;
  line-height: 1.12;
  letter-spacing: -0.03em;
}

p {
  margin: 0 0 1em;
}

menu,
ul,
ol {
  margin: 0;
  padding: 0;
  list-style: none;
}

article[id] {
  scroll-margin-top: 118px;
}

/* ---------- 顶部细条 ---------- */

.masthead {
  background: var(--paper);
  border-bottom: 1px solid var(--line);
}

.strip {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 10px;
  padding: 5px var(--pad);
  border-bottom: 1px solid var(--line);
  font-size: 14px;
}

.strip__b {
  font-weight: 700;
  letter-spacing: 0.18em;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

.strip__top {
  flex: 0 0 auto;
  display: inline-flex;
  align-items: center;
  min-height: 42px;
  margin: -12px -8px -12px 0;
  padding: 12px 8px;
  text-decoration: none;
  font-size: 14px;
  letter-spacing: 0.08em;
  color: #2a2a2a;
}

.strip__top:hover {
  text-decoration: underline;
  text-underline-offset: 4px;
}

/* ---------- 主栏：品牌居中，菜单分列两侧 ---------- */

.bar {
  display: grid;
  grid-template-columns: 1fr auto 1fr;
  align-items: center;
  gap: 8px;
  padding: 8px var(--pad);
  background: var(--paper);
}

.side {
  min-width: 0;
}

.side--r {
  justify-self: end;
}

.brand {
  justify-self: center;
  display: inline-flex;
  align-items: center;
  min-height: 44px;
  padding: 6px 10px;
  text-decoration: none;
}

.brand__text {
  font-size: clamp(17px, 4.6vw, 22px);
  font-weight: 700;
  letter-spacing: -0.03em;
  white-space: nowrap;
}

.brand__logo {
  display: block;
  height: 30px;
  width: auto;
}

/* ---------- 分组下拉 ---------- */

.dd {
  position: relative;
}

.dd__s {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  min-height: 44px;
  padding: 12px 14px;
  font-size: 16px;
  font-weight: 600;
  letter-spacing: 0.02em;
  border: 1px solid transparent;
  border-radius: 999px;
  cursor: pointer;
  list-style: none;
}

.dd__s::-webkit-details-marker {
  display: none;
}

.dd__s:hover {
  border-color: var(--line);
}

.dd__s::after {
  content: "";
  width: 6px;
  height: 6px;
  border-right: 1.6px solid currentColor;
  border-bottom: 1.6px solid currentColor;
  transform: rotate(45deg) translateY(-2px);
  transition: transform 0.2s ease;
}

.dd[open] .dd__s {
  background: var(--ink);
  color: var(--paper);
}

.dd[open] .dd__s::after {
  transform: rotate(-135deg) translateY(-2px);
}

.dd__m {
  position: absolute;
  top: calc(100% + 8px);
  left: 0;
  z-index: 40;
  min-width: 210px;
  padding: 8px;
  background: rgba(255, 255, 255, 0.94);
  -webkit-backdrop-filter: blur(16px);
  backdrop-filter: blur(16px);
  border: 1px solid var(--line);
  border-radius: 20px;
  box-shadow: 0 20px 44px rgba(0, 0, 0, 0.12);
}

.side--r .dd__m {
  left: auto;
  right: 0;
}

.dd__m a {
  display: flex;
  align-items: center;
  min-height: 44px;
  padding: 11px 14px;
  border-radius: 14px;
  text-decoration: none;
  font-size: 16px;
}

.dd__m a:hover {
  background: rgba(0, 0, 0, 0.06);
}

/* ---------- 粘性锚点条 ---------- */

.anchors {
  position: sticky;
  top: 0;
  z-index: 20;
  display: flex;
  gap: 2px;
  padding: 6px var(--pad);
  overflow-x: auto;
  scrollbar-width: none;
  background: rgba(255, 255, 255, 0.84);
  -webkit-backdrop-filter: blur(14px);
  backdrop-filter: blur(14px);
  border-bottom: 1px solid var(--line);
}

.anchors::-webkit-scrollbar {
  display: none;
}

.anchors a {
  flex: 0 0 auto;
  display: inline-flex;
  align-items: center;
  min-height: 44px;
  padding: 11px 14px;
  border-radius: 999px;
  font-size: 16px;
  font-weight: 500;
  text-decoration: none;
  white-space: nowrap;
}

.anchors a:hover {
  background: rgba(0, 0, 0, 0.07);
}

/* ---------- 版心与非对称分栏 ---------- */

.wrap {
  max-width: var(--maxw);
  margin: 0 auto;
  padding: 0 var(--pad);
}

.spread {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: clamp(24px, 4vw, 56px);
  padding-block: clamp(20px, 4vw, 44px);
}

@media (min-width: 960px) {
  .spread {
    grid-template-columns: minmax(0, 1fr) 296px;
  }
}

/* ---------- 首屏 ---------- */

.hero {
  display: grid;
  grid-template-columns: auto minmax(0, 1fr);
  align-items: center;
  gap: clamp(12px, 3vw, 28px);
  min-height: 62vh;
  padding-block: clamp(16px, 4vw, 40px);
  margin-bottom: clamp(20px, 3vw, 34px);
  border-bottom: 1px solid var(--line);
}

@media (max-width: 700px) {
  .hero {
    min-height: 48vh;
    align-items: start;
  }
}

.hero__mark {
  color: var(--ink);
}

.hero__mark svg {
  display: block;
  width: clamp(42px, 7vw, 72px);
  height: auto;
}

.hero__h1 {
  font-size: clamp(2rem, 6vw, 3.5rem);
  letter-spacing: -0.045em;
  text-wrap: balance;
}

.hero__desc {
  max-width: 46ch;
  margin: 0.75em 0 0;
  font-size: clamp(1rem, 2.1vw, 1.1rem);
  line-height: 1.62;
  color: #1a1a1a;
}

/* ---------- 正文 ---------- */

.body-col {
  min-width: 0;
}

.body-col > article {
  margin-bottom: clamp(18px, 2.6vw, 32px);
  padding: clamp(20px, 3.4vw, 40px);
  background: var(--glass);
  -webkit-backdrop-filter: blur(12px);
  backdrop-filter: blur(12px);
  border: 1px solid var(--line-soft);
  border-radius: var(--r);
}

.body-col h2 {
  margin-bottom: 0.55em;
  padding-top: 0.7em;
  border-top: 2px solid var(--ink);
  font-size: clamp(1.45rem, 3.4vw, 2.05rem);
  letter-spacing: -0.04em;
}

.body-col h3 {
  margin: 1.7em 0 0.5em;
  font-size: 1.16rem;
}

.body-col p {
  max-width: 68ch;
}

.body-col article > p:first-of-type::first-letter {
  float: left;
  padding: 0.06em 0.14em 0 0;
  font-size: 3.1em;
  font-weight: 700;
  line-height: 0.82;
  letter-spacing: -0.04em;
}

.body-col blockquote {
  margin: 1.6em 0;
  padding: 0.15em 0 0.15em 1.1em;
  border-left: 3px solid var(--ink);
  font-size: 1.1em;
  font-weight: 500;
  letter-spacing: -0.01em;
}

.body-col ul,
.body-col ol {
  margin: 0 0 1.2em;
}

.body-col li {
  position: relative;
  margin-bottom: 0.55em;
  padding-left: 1.4em;
}

.body-col li::before {
  content: "";
  position: absolute;
  left: 0;
  top: 0.66em;
  width: 8px;
  height: 2px;
  background: var(--ink);
}

@media (min-width: 1120px) {
  .body-col article ul,
  .body-col article ol {
    column-count: 2;
    column-gap: 2.4rem;
  }

  .body-col article li {
    break-inside: avoid;
  }
}

.body-col figure {
  margin: 1.6em 0;
}

.body-col figcaption {
  margin-top: 0.5em;
  font-size: 14px;
  line-height: 1.5;
  color: #4a4a4a;
}

.body-col a {
  text-underline-offset: 3px;
}

/* ---------- 右侧栏 ---------- */

.rail {
  align-self: start;
  padding: 22px 20px 18px;
  background: var(--glass);
  -webkit-backdrop-filter: blur(12px);
  backdrop-filter: blur(12px);
  border: 1px solid var(--line-soft);
  border-radius: var(--r);
}

@media (min-width: 960px) {
  .rail {
    position: sticky;
    top: 64px;
  }
}

.rail__h {
  font-size: 1.08rem;
  letter-spacing: 0.02em;
}

.subtitle {
  margin: 0.35em 0 1.1em;
  font-size: 14px;
  line-height: 1.5;
  letter-spacing: 0.1em;
  color: #525252;
}

.rail__list a {
  display: flex;
  align-items: center;
  gap: 10px;
  min-height: 42px;
  padding: 10px 8px;
  border-top: 1px solid var(--line-soft);
  border-radius: 10px;
  font-size: 16px;
  text-decoration: none;
}

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

.rail__list a:hover {
  background: rgba(0, 0, 0, 0.05);
}

.rail__n {
  font-size: 13px;
  letter-spacing: 0.12em;
  font-variant-numeric: tabular-nums;
  color: #6b6b6b;
}

/* ---------- 页脚 ---------- */

.foot {
  margin-top: clamp(32px, 6vw, 72px);
  padding: clamp(28px, 5vw, 56px) var(--pad) 0;
  background: var(--ink);
  color: var(--paper);
}

.foot > article + article {
  margin-top: clamp(22px, 4vw, 40px);
}

.foot__giant {
  margin: 0;
  font-size: clamp(2.3rem, 12vw, 7.5rem);
  font-weight: 700;
  line-height: 0.92;
  letter-spacing: -0.05em;
}

.foot__list {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 0 22px;
}

@media (min-width: 760px) {
  .foot__list {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }
}

.foot__list a {
  display: flex;
  align-items: center;
  min-height: 44px;
  padding: 8px 0;
  border-bottom: 1px solid rgba(255, 255, 255, 0.18);
  font-size: 16px;
  text-decoration: none;
  color: rgba(255, 255, 255, 0.9);
}

.foot__list a:hover {
  color: #ffffff;
  border-color: #ffffff;
}

.foot__base {
  padding-block: 18px;
  border-top: 1px solid rgba(255, 255, 255, 0.22);
  font-size: 14px;
  color: rgba(255, 255, 255, 0.72);
}

.foot__base p {
  margin: 0;
}

/* ---------- 滚动显现 ---------- */

html.js .rv {
  opacity: 0;
  transform: translateY(14px);
  transition: opacity 0.6s ease, transform 0.6s ease;
}

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

@media (prefers-reduced-motion: reduce) {
  html {
    scroll-behavior: auto;
  }

  html.js .rv,
  html.js .rv.in {
    opacity: 1;
    transform: none;
    transition: none;
  }

  .dd__s::after {
    transition: none;
  }
}

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