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

:root {
  --bg-deep: #050B18;
  --bg-night: #0B1526;
  --ice-white: #F3F8FF;
  --frost-silver: #A9B8CE;
  --ice-blue: #3D9BF0;
  --aurora-purple: #8E7BF2;
  --neon-cyan: #35F0DC;
  --crack-blue: #1B2A44;
  --mist-face: #E8F1FA;
  --header-h: 86px;
  --page-gutter: clamp(20px, 5vw, 72px);
  --content-max: 1240px;
  --text-max: 68ch;
  --font-display: "Inter", "Noto Sans SC", "Source Han Sans SC", "PingFang SC", "Microsoft YaHei", sans-serif;
  --font-mono: "JetBrains Mono", "IBM Plex Mono", ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
  --font-body: "Source Han Sans SC", "Noto Sans SC", "PingFang SC", "Microsoft YaHei", sans-serif;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  min-width: 320px;
  background:
    radial-gradient(circle at 12% -8%, rgba(61, 155, 240, .18), transparent 32%),
    radial-gradient(circle at 88% 8%, rgba(142, 123, 242, .14), transparent 34%),
    linear-gradient(180deg, var(--bg-deep) 0%, var(--bg-deep) 48%, var(--bg-night) 100%);
  background-attachment: fixed;
  color: var(--ice-white);
  font-family: var(--font-body);
  font-size: 17px;
  line-height: 1.9;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}

body::selection {
  background: rgba(61, 155, 240, .35);
  color: var(--ice-white);
}

a {
  color: inherit;
}

img {
  max-width: 100%;
}

button,
input,
select,
textarea {
  font: inherit;
}

:focus-visible {
  outline: 2px solid var(--ice-blue);
  outline-offset: 3px;
}

/* 跳转链接 */
.skip-link {
  position: fixed;
  top: 8px;
  left: 8px;
  z-index: 200;
  padding: 10px 14px;
  background: var(--ice-blue);
  color: #04101f;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: .08em;
  text-decoration: none;
  transform: translateY(-140%);
  transition: transform .2s ease;
}

.skip-link:focus {
  transform: translateY(0);
}

/* 头部 */
.site-header {
  position: sticky;
  top: 0;
  z-index: 80;
  background: linear-gradient(180deg, rgba(5, 11, 24, .96), rgba(5, 11, 24, .86));
  backdrop-filter: blur(18px);
  border-bottom: 1px solid var(--crack-blue);
}

.header-shell {
  width: min(100% - (var(--page-gutter) * 2), var(--content-max));
  min-height: var(--header-h);
  margin-inline: auto;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: clamp(20px, 5vw, 80px);
}

.brand-block {
  display: flex;
  align-items: center;
  gap: clamp(14px, 2vw, 22px);
  min-width: 0;
}

.brand-mark {
  display: inline-flex;
  align-items: center;
  gap: 14px;
  min-width: 0;
  text-decoration: none;
}

.brand-glyph {
  position: relative;
  display: inline-block;
  flex: 0 0 auto;
  width: 26px;
  height: 26px;
  border: 1px solid var(--ice-blue);
  background: linear-gradient(135deg, rgba(61, 155, 240, .35), rgba(142, 123, 242, .2));
  box-shadow: 0 0 18px rgba(61, 155, 240, .22);
  transform: rotate(45deg);
}

.brand-glyph::after {
  content: "";
  position: absolute;
  inset: 5px;
  border: 1px solid rgba(53, 240, 220, .7);
}

.brand-text {
  display: flex;
  flex-direction: column;
  min-width: 0;
}

.brand-name {
  font-family: var(--font-display);
  font-weight: 800;
  font-size: 18px;
  line-height: 1.2;
  letter-spacing: -.02em;
  color: var(--ice-white);
  white-space: nowrap;
}

.brand-descriptor {
  color: var(--frost-silver);
  font-size: 12px;
  line-height: 1.5;
  letter-spacing: .04em;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

.header-index {
  color: var(--frost-silver);
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: .18em;
  opacity: .6;
  white-space: nowrap;
}

.nav-toggle {
  display: none;
  align-items: center;
  gap: 8px;
  padding: 9px 11px;
  border: 1px solid var(--crack-blue);
  background: transparent;
  color: var(--ice-white);
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: .12em;
  cursor: pointer;
}

.nav-toggle-line {
  display: block;
  width: 18px;
  height: 1px;
  background: currentColor;
  box-shadow: 0 5px 0 currentColor;
}

.nav-toggle-label {
  line-height: 1;
}

.primary-nav {
  display: flex;
  align-items: center;
  gap: clamp(14px, 2vw, 30px);
  min-width: 0;
}

.nav-list {
  display: flex;
  align-items: center;
  gap: 2px;
  margin: 0;
  padding: 0;
  list-style: none;
}

.nav-link {
  position: relative;
  display: inline-block;
  padding: 10px 12px;
  color: var(--frost-silver);
  font-size: 14px;
  line-height: 1.2;
  letter-spacing: .04em;
  text-decoration: none;
  transition: color .2s ease;
}

.nav-link:hover {
  color: var(--ice-white);
}

.nav-link[aria-current="page"] {
  color: var(--ice-blue);
}

.nav-link[aria-current="page"]::after {
  content: "";
  position: absolute;
  left: 12px;
  right: 12px;
  bottom: 2px;
  height: 1px;
  background: var(--ice-blue);
}

.nav-utility {
  display: flex;
  align-items: center;
  gap: clamp(8px, 1.5vw, 16px);
}

.nav-utility-link {
  color: var(--frost-silver);
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: .08em;
  text-decoration: none;
  white-space: nowrap;
}

.nav-utility-link:hover {
  color: var(--ice-white);
}

.nav-cta {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 38px;
  padding: 0 14px;
  border: 1px solid var(--ice-blue);
  background: rgba(61, 155, 240, .1);
  color: var(--ice-white);
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: .08em;
  text-decoration: none;
  white-space: nowrap;
  transition: background .2s ease, color .2s ease;
}

.nav-cta:hover {
  background: var(--ice-blue);
  color: #04101f;
}

.header-crack {
  height: 1px;
  background: linear-gradient(90deg, transparent, var(--crack-blue) 12%, var(--ice-blue) 50%, var(--aurora-purple) 78%, transparent);
  opacity: .55;
}

/* 页脚 */
.site-footer {
  position: relative;
  margin-top: clamp(80px, 12vw, 160px);
  background: linear-gradient(180deg, var(--bg-night), var(--bg-deep));
  border-top: 1px solid var(--crack-blue);
}

.footer-shell {
  width: min(100% - (var(--page-gutter) * 2), var(--content-max));
  margin-inline: auto;
  padding: clamp(48px, 7vw, 88px) 0 clamp(28px, 4vw, 44px);
}

.footer-top {
  display: grid;
  grid-template-columns: minmax(260px, 1.3fr) minmax(420px, 2fr) minmax(220px, 1fr);
  gap: clamp(32px, 5vw, 72px);
}

.footer-brand {
  min-width: 0;
}

.footer-brand-link {
  display: inline-flex;
  align-items: center;
  gap: 14px;
  text-decoration: none;
}

.footer-brand-name {
  font-family: var(--font-display);
  font-weight: 800;
  font-size: 20px;
  line-height: 1.2;
  letter-spacing: -.02em;
  color: var(--ice-white);
}

.footer-summary {
  max-width: 46ch;
  margin: 22px 0 0;
  color: var(--frost-silver);
  font-size: 15px;
  line-height: 1.9;
}

.footer-note {
  margin: 12px 0 0;
  color: var(--ice-blue);
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: .12em;
}

.footer-nav {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: clamp(20px, 3vw, 40px);
}

.footer-group {
  min-width: 0;
}

.footer-group-title {
  margin: 0 0 16px;
  color: var(--ice-white);
  font-family: var(--font-mono);
  font-size: 11px;
  font-weight: 500;
  letter-spacing: .18em;
  text-transform: uppercase;
  opacity: .8;
}

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

.footer-link {
  display: inline-block;
  padding: 5px 0;
  color: var(--frost-silver);
  font-size: 14px;
  line-height: 1.7;
  text-decoration: none;
  transition: color .2s ease, padding-left .2s ease;
}

.footer-link:hover {
  color: var(--neon-cyan);
  padding-left: 4px;
}

.footer-contact-block {
  min-width: 0;
  padding-left: clamp(0px, 3vw, 34px);
  border-left: 1px solid var(--crack-blue);
}

.footer-contact-line {
  margin: 0 0 10px;
  color: var(--frost-silver);
  font-family: var(--font-mono);
  font-size: 12px;
  line-height: 1.8;
  word-break: break-word;
}

.footer-contact-window {
  color: var(--ice-blue);
}

.footer-bottom {
  display: flex;
  flex-wrap: wrap;
  justify-content: space-between;
  gap: 12px 24px;
  margin-top: 44px;
  padding-top: 20px;
  border-top: 1px solid var(--crack-blue);
}

.footer-meta {
  margin: 0;
  color: var(--frost-silver);
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: .08em;
  line-height: 1.7;
}

/* 主内容与布局 */
.site-main {
  display: block;
  min-height: 50vh;
}

.page-container {
  width: min(100% - (var(--page-gutter) * 2), var(--content-max));
  margin-inline: auto;
  padding-block: clamp(48px, 8vw, 120px);
}

.narrow {
  width: min(100% - (var(--page-gutter) * 2), 860px);
  margin-inline: auto;
}

.text-measure {
  max-width: var(--text-max);
}

.content-grid {
  display: grid;
  gap: clamp(24px, 4vw, 48px);
}

.grid-2 {
  grid-template-columns: repeat(2, minmax(0, 1fr));
}

.grid-3 {
  grid-template-columns: repeat(3, minmax(0, 1fr));
}

.grid-4 {
  grid-template-columns: repeat(4, minmax(0, 1fr));
}

/* 文字系统 */
.eyebrow {
  margin: 0 0 14px;
  color: var(--frost-silver);
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: .18em;
  text-transform: uppercase;
  opacity: .75;
}

.display-xl,
.display-lg,
.heading-2,
.heading-3 {
  font-family: var(--font-display);
  color: var(--ice-white);
  font-weight: 800;
  letter-spacing: -.02em;
}

.display-xl {
  margin: 0;
  font-size: clamp(42px, 7vw, 64px);
  line-height: 1.05;
}

.display-lg {
  margin: 0;
  font-size: clamp(34px, 5vw, 48px);
  line-height: 1.1;
}

.heading-2 {
  margin: 0;
  font-size: clamp(24px, 3vw, 28px);
  line-height: 1.35;
}

.heading-3 {
  margin: 0;
  font-size: 22px;
  line-height: 1.45;
}

.numeric-xl {
  display: block;
  margin: 0;
  color: var(--neon-cyan);
  font-family: var(--font-mono);
  font-size: clamp(52px, 8vw, 96px);
  font-weight: 500;
  line-height: 1;
  letter-spacing: .01em;
}

.lede {
  max-width: var(--text-max);
  margin: 0;
  color: var(--frost-silver);
  font-size: clamp(17px, 2vw, 20px);
  line-height: 1.9;
}

/* 按钮 */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 10px;
  min-height: 46px;
  padding: 0 22px;
  border: 1px solid var(--crack-blue);
  border-radius: 2px;
  background: rgba(61, 155, 240, .08);
  color: var(--ice-white);
  font-family: var(--font-mono);
  font-size: 14px;
  font-weight: 500;
  line-height: 1;
  letter-spacing: .06em;
  text-decoration: none;
  cursor: pointer;
  transition: background .2s ease, border-color .2s ease, color .2s ease, transform .2s ease;
}

.btn:hover {
  border-color: var(--ice-blue);
  background: rgba(61, 155, 240, .16);
  transform: translateY(-1px);
}

.btn-primary {
  border-color: var(--ice-blue);
  background: var(--ice-blue);
  color: #04101f;
}

.btn-primary:hover {
  background: var(--neon-cyan);
  border-color: var(--neon-cyan);
}

.btn-ghost {
  background: transparent;
}

.btn-small {
  min-height: 36px;
  padding: 0 14px;
  font-size: 12px;
}

/* 面包屑 */
.breadcrumb {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 8px;
  margin: 0 0 32px;
  color: var(--frost-silver);
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: .08em;
}

.breadcrumb a {
  color: inherit;
  text-decoration: none;
  border-bottom: 1px solid transparent;
  transition: color .2s ease, border-color .2s ease;
}

.breadcrumb a:hover {
  color: var(--ice-white);
  border-bottom-color: var(--ice-blue);
}

.breadcrumb-sep {
  opacity: .4;
}

/* 面板与卡片 */
.ice-card,
.ice-panel {
  position: relative;
  padding: clamp(22px, 3vw, 36px);
  border: 1px solid var(--crack-blue);
  border-radius: 2px;
  background: linear-gradient(145deg, rgba(11, 21, 38, .88), rgba(5, 11, 24, .92));
  box-shadow: 0 18px 50px rgba(0, 0, 0, .22);
}

.ice-card::after,
.ice-panel::after {
  content: "";
  position: absolute;
  inset: 0;
  border-radius: inherit;
  background: linear-gradient(135deg, rgba(61, 155, 240, .08), transparent 42%, rgba(142, 123, 242, .06));
  pointer-events: none;
}

.ice-panel--mist {
  border-color: transparent;
  background: var(--mist-face);
  color: #081326;
}

.ice-panel--mist::after {
  background: linear-gradient(135deg, rgba(61, 155, 240, .12), transparent 50%);
}

/* 标签与数据 */
.chip,
.tag {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 6px 10px;
  border: 1px solid var(--crack-blue);
  border-radius: 999px;
  color: var(--frost-silver);
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: .08em;
  line-height: 1.2;
}

.chip--hot {
  border-color: rgba(53, 240, 220, .35);
  color: var(--neon-cyan);
}

.tag {
  border-radius: 2px;
}

.metric-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(180px, 1fr));
  gap: 18px;
}

.metric {
  padding: 28px 18px;
  border-top: 1px solid var(--crack-blue);
  border-bottom: 1px solid var(--crack-blue);
  text-align: center;
}

.metric-value {
  display: block;
  color: var(--neon-cyan);
  font-family: var(--font-mono);
  font-size: clamp(36px, 5vw, 56px);
  font-weight: 500;
  line-height: 1;
  letter-spacing: .01em;
}

.metric-label {
  display: block;
  margin-top: 12px;
  color: var(--frost-silver);
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: .12em;
}

.divider-crack {
  height: 1px;
  margin-block: clamp(48px, 8vw, 96px);
  background: linear-gradient(90deg, transparent, var(--crack-blue) 18%, var(--ice-blue) 50%, var(--crack-blue) 82%, transparent);
  opacity: .7;
}

/* 图片容器 */
.image-frame {
  position: relative;
  overflow: hidden;
  border: 1px solid var(--crack-blue);
  background: linear-gradient(135deg, var(--bg-night), var(--bg-deep));
  isolation: isolate;
}

.image-frame img {
  display: block;
  width: 100%;
  height: 100%;
  object-fit: cover;
}

.image-frame--wide {
  aspect-ratio: 16 / 9;
}

.image-frame--tall {
  aspect-ratio: 3 / 4;
}

.image-frame--square {
  aspect-ratio: 1 / 1;
}

.image-fallback {
  position: absolute;
  inset: 0;
  display: grid;
  place-items: center;
  padding: 24px;
  color: var(--frost-silver);
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: .12em;
  text-align: center;
  background:
    radial-gradient(circle at 30% 20%, rgba(61, 155, 240, .18), transparent 42%),
    linear-gradient(135deg, rgba(142, 123, 242, .12), transparent 60%);
}

.image-caption {
  margin-top: 10px;
  color: var(--frost-silver);
  font-size: 13px;
  line-height: 1.7;
}

/* 标签页 */
.data-tabs {
  display: flex;
  flex-wrap: wrap;
  gap: 6px;
  padding-bottom: 12px;
  border-bottom: 1px solid var(--crack-blue);
}

.data-tab {
  padding: 9px 12px;
  border: 1px solid transparent;
  background: transparent;
  color: var(--frost-silver);
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: .08em;
  cursor: pointer;
}

.data-tab[aria-selected="true"] {
  border-color: var(--ice-blue);
  color: var(--neon-cyan);
}

.tab-panel {
  display: none;
  padding-top: 24px;
}

.tab-panel.is-active {
  display: block;
}

/* 折叠 */
.accordion {
  border-top: 1px solid var(--crack-blue);
}

.accordion-item {
  border-bottom: 1px solid var(--crack-blue);
}

.accordion-trigger {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 20px;
  width: 100%;
  padding: 20px 0;
  border: 0;
  background: none;
  color: var(--ice-white);
  font-size: 17px;
  line-height: 1.7;
  text-align: left;
  cursor: pointer;
}

.accordion-trigger::after {
  content: "+";
  color: var(--ice-blue);
  font-family: var(--font-mono);
  font-size: 18px;
}

.accordion-trigger[aria-expanded="true"]::after {
  content: "−";
  color: var(--neon-cyan);
}

.accordion-panel {
  display: none;
  max-width: var(--text-max);
  padding: 0 0 22px;
  color: var(--frost-silver);
}

.accordion-panel.is-open {
  display: block;
}

/* 章节跟随 */
.chapter-rail {
  position: fixed;
  top: 50%;
  right: clamp(12px, 2vw, 28px);
  z-index: 60;
  display: none;
  flex-direction: column;
  gap: 14px;
  transform: translateY(-50%);
}

.chapter-link {
  color: var(--frost-silver);
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: .12em;
  text-decoration: none;
  opacity: .55;
  transition: color .2s ease, opacity .2s ease;
}

.chapter-link.is-active {
  color: var(--neon-cyan);
  opacity: 1;
}

.chapter-section {
  scroll-margin-top: calc(var(--header-h) + 32px);
}

/* 动效与辅助 */
.reveal {
  opacity: 0;
  transform: translateY(16px);
  transition: opacity .24s ease-out, transform .24s ease-out;
}

.reveal.is-visible {
  opacity: 1;
  transform: none;
}

.scroll-progress {
  position: fixed;
  top: 0;
  left: 0;
  z-index: 120;
  width: 0;
  height: 2px;
  background: linear-gradient(90deg, var(--ice-blue), var(--aurora-purple), var(--neon-cyan));
  pointer-events: none;
}

.to-top {
  position: fixed;
  right: clamp(16px, 3vw, 32px);
  bottom: clamp(18px, 3vw, 36px);
  z-index: 70;
  width: 44px;
  height: 44px;
  border: 1px solid var(--crack-blue);
  background: rgba(5, 11, 24, .86);
  color: var(--ice-white);
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: .06em;
  cursor: pointer;
  opacity: 0;
  visibility: hidden;
  transform: translateY(8px);
  transition: opacity .2s ease, visibility .2s ease, transform .2s ease;
}

.to-top.is-visible {
  opacity: 1;
  visibility: visible;
  transform: none;
}

/* 分页 */
.pager {
  display: flex;
  justify-content: space-between;
  gap: 16px;
  margin-top: 64px;
  padding-top: 24px;
  border-top: 1px solid var(--crack-blue);
}

.pager-link {
  color: var(--frost-silver);
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: .08em;
  text-decoration: none;
}

.pager-link:hover {
  color: var(--neon-cyan);
}

/* 响应式 */
@media (min-width: 1180px) {
  .chapter-rail {
    display: flex;
  }
}

@media (max-width: 1080px) {
  .footer-top {
    grid-template-columns: 1fr 1fr;
  }

  .footer-brand,
  .footer-nav,
  .footer-contact-block {
    grid-column: 1 / -1;
  }

  .footer-contact-block {
    padding-left: 0;
    border-left: 0;
    padding-top: 24px;
    border-top: 1px solid var(--crack-blue);
  }
}

@media (max-width: 920px) {
  :root {
    --header-h: 72px;
  }

  .brand-descriptor {
    display: none;
  }

  .header-index {
    display: none;
  }

  .nav-toggle {
    display: inline-flex;
  }

  .primary-nav {
    position: fixed;
    top: calc(var(--header-h) + 8px);
    left: var(--page-gutter);
    right: var(--page-gutter);
    z-index: 90;
    display: flex;
    flex-direction: column;
    align-items: stretch;
    gap: 18px;
    padding: 22px;
    border: 1px solid var(--crack-blue);
    background: linear-gradient(180deg, rgba(11, 21, 38, .98), rgba(5, 11, 24, .98));
    box-shadow: 0 30px 80px rgba(0, 0, 0, .45);
    opacity: 0;
    visibility: hidden;
    transform: translateY(-10px);
    pointer-events: none;
    transition: opacity .2s ease, transform .2s ease, visibility .2s ease;
  }

  .site-header[data-open="true"] .primary-nav {
    opacity: 1;
    visibility: visible;
    transform: none;
    pointer-events: auto;
  }

  .nav-list {
    flex-direction: column;
    align-items: stretch;
    gap: 0;
  }

  .nav-link {
    display: block;
    padding: 14px 0;
    border-bottom: 1px solid var(--crack-blue);
    font-size: 16px;
  }

  .nav-link[aria-current="page"]::after {
    left: 0;
    right: auto;
    bottom: 8px;
    width: 36px;
  }

  .nav-utility {
    flex-direction: column;
    align-items: stretch;
    padding-top: 16px;
    border-top: 1px solid var(--crack-blue);
  }

  .nav-utility-link {
    display: block;
    padding: 8px 0;
  }

  .nav-cta {
    width: 100%;
  }
}

@media (max-width: 760px) {
  .grid-2,
  .grid-3,
  .grid-4 {
    grid-template-columns: 1fr;
  }

  .footer-nav {
    grid-template-columns: 1fr 1fr;
  }

  .page-container {
    padding-block: clamp(36px, 10vw, 72px);
  }
}

@media (max-width: 520px) {
  .footer-nav {
    grid-template-columns: 1fr;
  }

  .footer-bottom {
    flex-direction: column;
  }

  .brand-name {
    font-size: 16px;
  }
}

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

  *,
  *::before,
  *::after {
    animation-duration: .01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: .01ms !important;
    scroll-behavior: auto !important;
  }

  .reveal {
    opacity: 1;
    transform: none;
  }
}