/* =========================================================
   宝马740娱乐 · 共享样式表 /assets/site.css
   城央夜色 / 极简文字建筑 / 玻璃层与实色层并置
   ========================================================= */

/* ---------- 1. Reset ---------- */
*,
*::before,
*::after { box-sizing: border-box; }

html {
  -webkit-text-size-adjust: 100%;
  scroll-behavior: smooth;
  scroll-padding-top: 120px;
}

body,
h1, h2, h3, h4, h5, h6,
p, ul, ol, li, figure, figcaption, blockquote, dl, dd { margin: 0; padding: 0; }

ul, ol { list-style: none; }

img, svg, video, canvas { display: block; max-width: 100%; }

a { color: inherit; text-decoration: none; }

button, input, select, textarea {
  font: inherit;
  color: inherit;
  background: none;
  border: 0;
}

button { cursor: pointer; }

table { border-collapse: collapse; width: 100%; }

/* ---------- 2. 设计变量 ---------- */
:root {
  /* 色板 */
  --cy-night: #081A33;
  --cy-blue: #0F3D7A;
  --cy-cyan: #22D3EE;
  --cy-gold: #C8A96A;
  --cy-carbon: #0B0D10;
  --cy-glass: #151A22;
  --cy-ice: #EAF2FF;
  --cy-mist: #98A6BD;
  --cy-violet: #1B2A55;
  --cy-ok: #34D399;
  --cy-warn: #F59E0B;

  --cy-line: rgba(234, 242, 255, .12);
  --cy-line-soft: rgba(234, 242, 255, .07);
  --cy-line-strong: rgba(34, 211, 238, .45);
  --cy-glass-bg: rgba(21, 26, 34, .72);
  --cy-glass-bg-hi: rgba(21, 26, 34, .9);

  /* 字体 */
  --cy-font-sans: "HarmonyOS Sans SC", "PingFang SC", "Source Han Sans SC", "Noto Sans SC", "Microsoft YaHei", system-ui, -apple-system, "Segoe UI", sans-serif;
  --cy-font-mono: "JetBrains Mono", "Roboto Mono", ui-monospace, SFMono-Regular, Menlo, Consolas, "Courier New", monospace;

  /* 字号 */
  --cy-display: clamp(2.75rem, 7.6vw, 7rem);
  --cy-h2: clamp(1.65rem, 3.1vw, 2.5rem);
  --cy-h3: clamp(1.1rem, 1.6vw, 1.4rem);
  --cy-body: clamp(.95rem, .34vw + .87rem, 1.0625rem);
  --cy-index: .75rem;

  /* 结构 */
  --cy-max: 1280px;
  --cy-gutter: clamp(1rem, 4vw, 3.5rem);
  --cy-radius: 18px;
  --cy-radius-lg: 28px;
  --cy-header-h: 76px;

  /* 动效 */
  --cy-ease: cubic-bezier(.22, .61, .36, 1);
  --cy-dur: 200ms;

  --cy-shadow: 0 24px 60px -34px rgba(0, 0, 0, .9);
}

/* ---------- 3. 基础排版 ---------- */
body {
  font-family: var(--cy-font-sans);
  font-size: var(--cy-body);
  line-height: 1.75;
  color: var(--cy-ice);
  background-color: var(--cy-night);
  background-image:
    radial-gradient(1200px 620px at 84% -10%, rgba(34, 211, 238, .10), transparent 62%),
    radial-gradient(900px 520px at 6% 2%, rgba(200, 169, 106, .07), transparent 60%),
    radial-gradient(1000px 700px at 50% 120%, rgba(27, 42, 85, .55), transparent 70%);
  background-repeat: no-repeat;
  min-height: 100vh;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  overflow-x: hidden;
}

h1, h2, h3, h4 {
  font-weight: 400;
  letter-spacing: .01em;
  line-height: 1.18;
  color: var(--cy-ice);
}

h1 { font-size: var(--cy-display); }
h2 { font-size: var(--cy-h2); }
h3 { font-size: var(--cy-h3); font-weight: 500; }

::selection {
  background: rgba(34, 211, 238, .32);
  color: #ffffff;
}

:focus-visible {
  outline: 2px solid var(--cy-cyan);
  outline-offset: 3px;
  border-radius: 4px;
}

/* ---------- 4. 跳转链接 ---------- */
.cy-skip {
  position: fixed;
  left: 50%;
  top: -120px;
  transform: translateX(-50%);
  z-index: 300;
  padding: .7rem 1.4rem;
  border-radius: 999px;
  background: var(--cy-cyan);
  color: #04202B;
  font-size: .875rem;
  font-weight: 600;
  letter-spacing: .06em;
  transition: top var(--cy-dur) var(--cy-ease);
}

.cy-skip:focus {
  top: 14px;
}

/* ---------- 5. 布局容器 ---------- */
.cy-container {
  width: 100%;
  max-width: var(--cy-max);
  margin-inline: auto;
  padding-inline: var(--cy-gutter);
}

.cy-main {
  display: block;
  padding-top: clamp(1.25rem, 3vw, 2.5rem);
  padding-bottom: clamp(3rem, 8vw, 7rem);
}

/* ---------- 6. 悬浮胶囊头部 ---------- */
.cy-header {
  position: sticky;
  top: 0;
  z-index: 90;
  padding: clamp(.6rem, 1.4vw, 1.05rem) 0 clamp(.45rem, .9vw, .8rem);
}

.cy-header::before {
  content: "";
  position: absolute;
  inset: 0 0 auto 0;
  height: 100%;
  pointer-events: none;
  background: linear-gradient(180deg,
    rgba(6, 20, 40, .96) 0%,
    rgba(6, 20, 40, .74) 58%,
    rgba(6, 20, 40, 0) 100%);
}

.cy-header__capsule {
  position: relative;
  width: calc(100% - 2 * var(--cy-gutter));
  max-width: var(--cy-max);
  margin-inline: auto;
  display: flex;
  align-items: center;
  gap: clamp(.5rem, 1.5vw, 1.5rem);
  padding: .5rem .5rem .5rem clamp(.85rem, 1.6vw, 1.35rem);
  border: 1px solid var(--cy-line);
  border-radius: 999px;
  background: var(--cy-glass-bg);
  -webkit-backdrop-filter: blur(16px) saturate(140%);
  backdrop-filter: blur(16px) saturate(140%);
  box-shadow: var(--cy-shadow);
  transition: border-color var(--cy-dur) var(--cy-ease),
              background var(--cy-dur) var(--cy-ease);
}

.cy-header__capsule:hover {
  border-color: rgba(234, 242, 255, .2);
}

/* 品牌 */
.cy-brand {
  display: inline-flex;
  align-items: center;
  gap: .7rem;
  flex: 0 0 auto;
  min-width: 0;
}

.cy-brand__mark {
  position: relative;
  flex: 0 0 auto;
  width: 30px;
  height: 30px;
  border-radius: 50%;
  background:
    radial-gradient(circle at 30% 24%, rgba(255, 255, 255, .9), rgba(255, 255, 255, 0) 44%),
    conic-gradient(from 140deg, var(--cy-cyan), var(--cy-blue) 46%, var(--cy-gold) 78%, var(--cy-cyan));
  box-shadow: 0 0 0 1px rgba(234, 242, 255, .18),
              0 0 20px -3px rgba(34, 211, 238, .75);
  transition: box-shadow var(--cy-dur) var(--cy-ease);
}

.cy-brand__mark::after {
  content: "";
  position: absolute;
  inset: 9px;
  border-radius: 50%;
  background: var(--cy-night);
}

.cy-brand:hover .cy-brand__mark,
.cy-brand:focus-visible .cy-brand__mark {
  box-shadow: 0 0 0 1px rgba(234, 242, 255, .32),
              0 0 26px -2px rgba(34, 211, 238, .95);
}

.cy-brand__text {
  display: flex;
  flex-direction: column;
  min-width: 0;
  line-height: 1.12;
}

.cy-brand__name {
  font-size: 1rem;
  font-weight: 600;
  letter-spacing: .08em;
  color: var(--cy-ice);
  white-space: nowrap;
}

.cy-brand__tagline {
  font-family: var(--cy-font-mono);
  font-size: .625rem;
  letter-spacing: .2em;
  color: var(--cy-gold);
  white-space: nowrap;
}

/* 主导航 */
.cy-nav {
  flex: 1 1 auto;
  min-width: 0;
  display: flex;
  justify-content: center;
}

.cy-nav__list {
  display: flex;
  align-items: center;
  gap: clamp(.05rem, .5vw, .35rem);
}

.cy-nav__item {
  display: flex;
}

.cy-nav__link {
  position: relative;
  display: block;
  padding: .5rem clamp(.4rem, .9vw, .8rem);
  border-radius: 999px;
  font-size: .8125rem;
  letter-spacing: .07em;
  color: var(--cy-mist);
  white-space: nowrap;
  transition: color var(--cy-dur) var(--cy-ease),
              background var(--cy-dur) var(--cy-ease),
              box-shadow var(--cy-dur) var(--cy-ease);
}

.cy-nav__link::after {
  content: "";
  position: absolute;
  left: 18%;
  right: 18%;
  bottom: .28rem;
  height: 1px;
  background: var(--cy-cyan);
  transform: scaleX(0);
  transform-origin: center;
  transition: transform var(--cy-dur) var(--cy-ease);
}

.cy-nav__link:hover,
.cy-nav__link:focus-visible {
  color: var(--cy-ice);
  background: rgba(234, 242, 255, .06);
}

.cy-nav__link:hover::after,
.cy-nav__link:focus-visible::after {
  transform: scaleX(1);
}

.cy-nav__link[aria-current="page"] {
  color: var(--cy-ice);
  background: rgba(34, 211, 238, .12);
  box-shadow: inset 0 0 0 1px rgba(34, 211, 238, .3);
}

.cy-nav__link[aria-current="page"]::after {
  transform: scaleX(1);
}

/* 工具区 */
.cy-tools {
  display: flex;
  align-items: center;
  gap: .4rem;
  flex: 0 0 auto;
}

.cy-tool {
  display: inline-flex;
  align-items: center;
  gap: .45rem;
  padding: .5rem .85rem;
  border: 1px solid var(--cy-line);
  border-radius: 999px;
  background: rgba(234, 242, 255, .04);
  color: var(--cy-mist);
  font-size: .75rem;
  letter-spacing: .08em;
  white-space: nowrap;
  transition: color var(--cy-dur) var(--cy-ease),
              border-color var(--cy-dur) var(--cy-ease),
              background var(--cy-dur) var(--cy-ease);
}

.cy-tool:hover,
.cy-tool:focus-visible {
  color: var(--cy-ice);
  border-color: var(--cy-line-strong);
  background: rgba(34, 211, 238, .1);
}

.cy-tool--accent {
  color: var(--cy-cyan);
  border-color: rgba(34, 211, 238, .3);
}

.cy-tool__dot {
  flex: 0 0 auto;
  width: 6px;
  height: 6px;
  border-radius: 50%;
  background: currentColor;
  box-shadow: 0 0 8px currentColor;
}

.cy-tool[aria-pressed="true"] {
  color: var(--cy-gold);
  border-color: rgba(200, 169, 106, .55);
  background: rgba(200, 169, 106, .12);
}

/* 移动导航按钮 */
.cy-nav-toggle {
  position: relative;
  display: none;
  flex: 0 0 auto;
  width: 42px;
  height: 42px;
  border: 1px solid var(--cy-line);
  border-radius: 50%;
  background: rgba(234, 242, 255, .05);
  transition: border-color var(--cy-dur) var(--cy-ease),
              background var(--cy-dur) var(--cy-ease);
}

.cy-nav-toggle:hover,
.cy-nav-toggle:focus-visible {
  border-color: var(--cy-line-strong);
  background: rgba(34, 211, 238, .1);
}

.cy-nav-toggle__bar {
  position: absolute;
  left: 12px;
  right: 12px;
  height: 1.5px;
  border-radius: 2px;
  background: var(--cy-ice);
  transition: transform var(--cy-dur) var(--cy-ease),
              opacity 120ms linear;
}

.cy-nav-toggle__bar:nth-child(1) { top: 15px; }
.cy-nav-toggle__bar:nth-child(2) { top: 20px; }
.cy-nav-toggle__bar:nth-child(3) { top: 25px; }

.cy-header[data-open] .cy-nav-toggle__bar:nth-child(1) {
  transform: translateY(5px) rotate(45deg);
}

.cy-header[data-open] .cy-nav-toggle__bar:nth-child(2) {
  opacity: 0;
}

.cy-header[data-open] .cy-nav-toggle__bar:nth-child(3) {
  transform: translateY(-5px) rotate(-45deg);
}

/* ---------- 7. 章节骨架 ---------- */
.cy-section {
  padding-block: clamp(1.75rem, 5vw, 4rem);
}

.cy-section__head {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  gap: .6rem 1.25rem;
  margin-bottom: clamp(1.1rem, 2.5vw, 2rem);
}

.cy-section__index {
  font-family: var(--cy-font-mono);
  font-size: var(--cy-index);
  letter-spacing: .24em;
  color: var(--cy-cyan);
  text-transform: uppercase;
}

.cy-section__title {
  font-size: var(--cy-h2);
  font-weight: 400;
  line-height: 1.16;
}

.cy-eyebrow {
  display: inline-block;
  font-family: var(--cy-font-mono);
  font-size: var(--cy-index);
  letter-spacing: .2em;
  color: var(--cy-gold);
  text-transform: uppercase;
}

.cy-lead {
  max-width: 46ch;
  font-size: clamp(1rem, .5vw + .92rem, 1.15rem);
  line-height: 1.8;
  color: rgba(234, 242, 255, .82);
}

/* ---------- 8. 正文容器 ---------- */
.cy-prose {
  max-width: 68ch;
}

.cy-prose p {
  margin-bottom: 1.1em;
  color: rgba(234, 242, 255, .86);
}

.cy-prose h2 {
  margin: 2em 0 .6em;
  font-size: var(--cy-h2);
}

.cy-prose h3 {
  margin: 1.6em 0 .5em;
  font-size: var(--cy-h3);
}

.cy-prose ul,
.cy-prose ol {
  margin: 0 0 1.2em;
  padding-left: 1.2em;
}

.cy-prose li {
  margin-bottom: .45em;
  list-style: disc;
  color: rgba(234, 242, 255, .86);
}

.cy-prose strong {
  font-weight: 600;
  color: var(--cy-ice);
}

.cy-prose a {
  color: var(--cy-cyan);
  border-bottom: 1px solid rgba(34, 211, 238, .35);
  transition: border-color var(--cy-dur) var(--cy-ease);
}

.cy-prose a:hover {
  border-color: var(--cy-cyan);
}

.cy-prose code {
  font-family: var(--cy-font-mono);
  font-size: .85em;
  padding: .12em .42em;
  border-radius: 5px;
  color: var(--cy-gold);
  background: rgba(200, 169, 106, .1);
}

/* ---------- 9. 网格 ---------- */
.cy-grid {
  display: grid;
  gap: clamp(1rem, 2vw, 1.75rem);
}

.cy-grid--2 { grid-template-columns: repeat(2, minmax(0, 1fr)); }
.cy-grid--3 { grid-template-columns: repeat(3, minmax(0, 1fr)); }

.cy-grid--aside {
  grid-template-columns: minmax(0, 15rem) minmax(0, 1fr);
  align-items: start;
}

/* ---------- 10. 卡片与面板 ---------- */
.cy-panel {
  position: relative;
  padding: clamp(1.15rem, 2.6vw, 2rem);
  border: 1px solid var(--cy-line);
  border-radius: var(--cy-radius-lg);
  background: var(--cy-glass-bg);
  -webkit-backdrop-filter: blur(14px) saturate(130%);
  backdrop-filter: blur(14px) saturate(130%);
  overflow: hidden;
}

.cy-card {
  position: relative;
  display: flex;
  flex-direction: column;
  gap: .6rem;
  padding: clamp(1.05rem, 2vw, 1.6rem);
  border: 1px solid var(--cy-line);
  border-radius: var(--cy-radius);
  background: linear-gradient(180deg, rgba(21, 26, 34, .86), rgba(11, 13, 16, .74));
  transition: border-color var(--cy-dur) var(--cy-ease),
              transform var(--cy-dur) var(--cy-ease),
              background var(--cy-dur) var(--cy-ease);
}

.cy-card:hover,
.cy-card:focus-within {
  border-color: var(--cy-line-strong);
  background: linear-gradient(180deg, rgba(27, 42, 85, .82), rgba(11, 13, 16, .78));
  transform: translateY(-3px);
}

.cy-card__eyebrow {
  font-family: var(--cy-font-mono);
  font-size: var(--cy-index);
  letter-spacing: .18em;
  color: var(--cy-cyan);
  text-transform: uppercase;
}

.cy-card__title {
  font-size: clamp(1.05rem, 1.4vw, 1.25rem);
  font-weight: 500;
  line-height: 1.35;
  color: var(--cy-ice);
}

.cy-card__text {
  font-size: .9rem;
  line-height: 1.75;
  color: var(--cy-mist);
}

.cy-card__meta {
  display: flex;
  flex-wrap: wrap;
  gap: .35rem .7rem;
  font-family: var(--cy-font-mono);
  font-size: .6875rem;
  letter-spacing: .1em;
  color: var(--cy-mist);
}

.cy-card__link {
  display: inline-flex;
  align-items: center;
  gap: .4rem;
  margin-top: auto;
  padding-top: .5rem;
  font-size: .8125rem;
  letter-spacing: .06em;
  color: var(--cy-cyan);
}

.cy-card__link::after {
  content: "→";
  transition: transform var(--cy-dur) var(--cy-ease);
}

.cy-card__link:hover::after,
.cy-card__link:focus-visible::after {
  transform: translateX(4px);
}

/* ---------- 11. 图片容器基础 ---------- */
.cy-media {
  position: relative;
  overflow: hidden;
  border: 1px solid var(--cy-line);
  border-radius: var(--cy-radius);
  background:
    radial-gradient(120% 90% at 10% 0%, rgba(34, 211, 238, .22), transparent 60%),
    linear-gradient(150deg, var(--cy-violet), var(--cy-carbon) 72%);
}

.cy-media > img {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  object-fit: cover;
}

.cy-media::after {
  content: "";
  position: absolute;
  inset: 0;
  pointer-events: none;
  background:
    radial-gradient(120% 90% at 8% 0%, rgba(34, 211, 238, .18), transparent 58%),
    linear-gradient(160deg, rgba(8, 26, 51, .06), rgba(11, 13, 16, .62));
}

.cy-media--16x9 { aspect-ratio: 16 / 9; }
.cy-media--4x5 { aspect-ratio: 4 / 5; }
.cy-media--wide { aspect-ratio: 21 / 9; }

.cy-media__caption {
  position: absolute;
  left: 1rem;
  right: 1rem;
  bottom: .9rem;
  z-index: 2;
  font-family: var(--cy-font-mono);
  font-size: .6875rem;
  letter-spacing: .12em;
  color: rgba(234, 242, 255, .82);
}

/* ---------- 12. 按钮 ---------- */
.cy-btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: .5rem;
  padding: .75rem 1.5rem;
  border: 1px solid transparent;
  border-radius: 999px;
  font-size: .875rem;
  font-weight: 500;
  letter-spacing: .06em;
  text-align: center;
  transition: background var(--cy-dur) var(--cy-ease),
              color var(--cy-dur) var(--cy-ease),
              border-color var(--cy-dur) var(--cy-ease),
              box-shadow var(--cy-dur) var(--cy-ease),
              transform var(--cy-dur) var(--cy-ease);
}

.cy-btn--primary {
  background: var(--cy-cyan);
  color: #03212A;
  box-shadow: 0 14px 32px -16px rgba(34, 211, 238, .95);
}

.cy-btn--primary:hover,
.cy-btn--primary:focus-visible {
  background: #5EE7F5;
  transform: translateY(-1px);
}

.cy-btn--gold {
  border-color: rgba(200, 169, 106, .6);
  color: var(--cy-gold);
}

.cy-btn--gold:hover,
.cy-btn--gold:focus-visible {
  background: rgba(200, 169, 106, .12);
  border-color: var(--cy-gold);
}

.cy-btn--ghost {
  border-color: var(--cy-line);
  background: rgba(234, 242, 255, .05);
  color: var(--cy-ice);
}

.cy-btn--ghost:hover,
.cy-btn--ghost:focus-visible {
  border-color: var(--cy-line-strong);
  background: rgba(34, 211, 238, .1);
}

/* ---------- 13. 面包屑 ---------- */
.cy-breadcrumb {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: .4rem .6rem;
  padding-block: .9rem;
  font-family: var(--cy-font-mono);
  font-size: .6875rem;
  letter-spacing: .14em;
  color: var(--cy-mist);
}

.cy-breadcrumb a {
  transition: color var(--cy-dur) var(--cy-ease);
}

.cy-breadcrumb a:hover,
.cy-breadcrumb a:focus-visible {
  color: var(--cy-cyan);
}

.cy-breadcrumb__sep {
  color: rgba(152, 166, 189, .5);
}

/* ---------- 14. 状态标签 ---------- */
.cy-tag {
  display: inline-flex;
  align-items: center;
  gap: .35rem;
  padding: .2rem .6rem;
  border: 1px solid var(--cy-line);
  border-radius: 6px;
  font-family: var(--cy-font-mono);
  font-size: .6875rem;
  letter-spacing: .1em;
  color: var(--cy-mist);
}

.cy-tag--live {
  color: var(--cy-ok);
  border-color: rgba(52, 211, 153, .42);
  background: rgba(52, 211, 153, .1);
}

.cy-tag--wait {
  color: var(--cy-warn);
  border-color: rgba(245, 158, 11, .42);
  background: rgba(245, 158, 11, .1);
}

.cy-tag--gold {
  color: var(--cy-gold);
  border-color: rgba(200, 169, 106, .42);
  background: rgba(200, 169, 106, .1);
}

.cy-tag--cyan {
  color: var(--cy-cyan);
  border-color: rgba(34, 211, 238, .42);
  background: rgba(34, 211, 238, .1);
}

/* ---------- 15. 数据面板 ---------- */
.cy-stat {
  display: flex;
  flex-direction: column;
  gap: .15rem;
}

.cy-stat__num {
  font-family: var(--cy-font-mono);
  font-size: clamp(1.3rem, 2.4vw, 1.9rem);
  line-height: 1.2;
  letter-spacing: .02em;
  color: var(--cy-gold);
}

.cy-stat__label {
  font-size: .75rem;
  letter-spacing: .1em;
  color: var(--cy-mist);
}

/* ---------- 16. 步骤路径 ---------- */
.cy-steps {
  display: grid;
  gap: 1px;
  border: 1px solid var(--cy-line);
  border-radius: var(--cy-radius);
  background: var(--cy-line);
  overflow: hidden;
  counter-reset: cy-step;
}

.cy-step {
  counter-increment: cy-step;
  display: grid;
  gap: .3rem;
  padding: 1.1rem 1.25rem;
  background: rgba(11, 13, 16, .62);
  transition: background var(--cy-dur) var(--cy-ease);
}

.cy-step:hover {
  background: rgba(15, 61, 122, .34);
}

.cy-step__no {
  font-family: var(--cy-font-mono);
  font-size: var(--cy-index);
  letter-spacing: .2em;
  color: var(--cy-cyan);
}

.cy-step__no::before {
  content: counter(cy-step, decimal-leading-zero) " / ";
}

.cy-step__title {
  font-size: 1rem;
  font-weight: 500;
  color: var(--cy-ice);
}

.cy-step__text {
  font-size: .875rem;
  line-height: 1.7;
  color: var(--cy-mist);
}

/* ---------- 17. 阅读进度与返回顶部 ---------- */
.cy-progress {
  position: fixed;
  top: 0;
  left: 0;
  z-index: 120;
  width: 100%;
  height: 2px;
  transform: scaleX(0);
  transform-origin: 0 50%;
  background: linear-gradient(90deg, var(--cy-cyan), var(--cy-gold));
  pointer-events: none;
}

.cy-to-top {
  position: fixed;
  right: clamp(.8rem, 2vw, 1.6rem);
  bottom: clamp(.8rem, 2vw, 1.6rem);
  z-index: 110;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 46px;
  height: 46px;
  border: 1px solid var(--cy-line);
  border-radius: 50%;
  background: var(--cy-glass-bg-hi);
  -webkit-backdrop-filter: blur(12px);
  backdrop-filter: blur(12px);
  color: var(--cy-ice);
  opacity: 0;
  visibility: hidden;
  transform: translateY(10px);
  transition: opacity var(--cy-dur) var(--cy-ease),
              transform var(--cy-dur) var(--cy-ease),
              visibility var(--cy-dur) var(--cy-ease),
              border-color var(--cy-dur) var(--cy-ease);
}

.cy-to-top::before {
  content: "";
  width: 9px;
  height: 9px;
  border-left: 1.5px solid currentColor;
  border-top: 1.5px solid currentColor;
  transform: translateY(2px) rotate(45deg);
}

.cy-to-top:hover,
.cy-to-top:focus-visible {
  border-color: var(--cy-line-strong);
  color: var(--cy-cyan);
}

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

/* ---------- 18. 进入视口显现 ---------- */
.cy-reveal {
  transition: opacity 460ms var(--cy-ease), transform 460ms var(--cy-ease);
}

.cy-reveal.cy-reveal--armed {
  opacity: 0;
  transform: translateY(16px);
}

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

/* ---------- 19. 页脚 ---------- */
.cy-footer {
  position: relative;
  margin-top: clamp(2.5rem, 7vw, 6rem);
  background: var(--cy-carbon);
  border-top: 1px solid var(--cy-line);
  overflow: hidden;
}

.cy-footer::before {
  content: "";
  position: absolute;
  inset: 0;
  pointer-events: none;
  background:
    radial-gradient(720px 320px at 10% 0%, rgba(34, 211, 238, .1), transparent 62%),
    radial-gradient(620px 300px at 88% 6%, rgba(200, 169, 106, .08), transparent 60%);
}

.cy-footer__inner {
  position: relative;
  width: 100%;
  max-width: var(--cy-max);
  margin-inline: auto;
  padding: clamp(2.25rem, 6vw, 4.5rem) var(--cy-gutter) 0;
}

.cy-footer__top {
  display: grid;
  grid-template-columns: minmax(0, 1.5fr) repeat(3, minmax(0, 1fr));
  gap: clamp(1.5rem, 3vw, 3rem);
  padding-bottom: clamp(1.75rem, 4vw, 3rem);
  border-bottom: 1px solid var(--cy-line);
}

.cy-footer__brand {
  display: flex;
  flex-direction: column;
  gap: .55rem;
}

.cy-footer__wordmark {
  font-size: clamp(1.35rem, 2.6vw, 1.9rem);
  font-weight: 400;
  letter-spacing: .06em;
  line-height: 1.2;
  color: var(--cy-ice);
}

.cy-footer__claim {
  font-family: var(--cy-font-mono);
  font-size: var(--cy-index);
  letter-spacing: .22em;
  color: var(--cy-gold);
}

.cy-footer__note {
  max-width: 40ch;
  font-size: .875rem;
  line-height: 1.8;
  color: var(--cy-mist);
}

.cy-footer__col {
  display: flex;
  flex-direction: column;
  gap: .85rem;
}

.cy-footer__title {
  font-family: var(--cy-font-mono);
  font-size: var(--cy-index);
  letter-spacing: .2em;
  color: rgba(234, 242, 255, .55);
  text-transform: uppercase;
}

.cy-footer__list {
  display: flex;
  flex-direction: column;
  gap: .5rem;
}

.cy-footer__list--plain {
  gap: .55rem;
}

.cy-footer__link {
  display: inline-block;
  font-size: .9rem;
  color: var(--cy-mist);
  border-bottom: 1px solid transparent;
  transition: color var(--cy-dur) var(--cy-ease),
              border-color var(--cy-dur) var(--cy-ease);
}

.cy-footer__link:hover,
.cy-footer__link:focus-visible {
  color: var(--cy-cyan);
  border-bottom-color: rgba(34, 211, 238, .55);
}

.cy-footer__text {
  font-size: .875rem;
  line-height: 1.7;
  color: var(--cy-mist);
  word-break: break-word;
}

.cy-footer__bottom {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: .5rem 1.5rem;
  padding-block: clamp(1.1rem, 2.5vw, 1.75rem);
}

.cy-footer__legal {
  font-family: var(--cy-font-mono);
  font-size: .6875rem;
  letter-spacing: .1em;
  line-height: 1.7;
  color: rgba(152, 166, 189, .8);
}

/* ---------- 20. 响应式 ---------- */
@media (max-width: 1180px) {
  .cy-brand__tagline { display: none; }
}

@media (max-width: 960px) {
  .cy-header__capsule {
    flex-wrap: wrap;
    border-radius: 26px;
    padding: .55rem .55rem .55rem 1rem;
  }

  .cy-nav-toggle {
    display: block;
    margin-left: auto;
  }

  .cy-nav {
    order: 3;
    flex: 1 1 100%;
    display: none;
    padding: .35rem .15rem .25rem;
  }

  .cy-tools {
    order: 4;
    flex: 1 1 100%;
    display: none;
    padding: 0 .15rem .45rem;
  }

  .cy-header[data-open] .cy-nav { display: block; }
  .cy-header[data-open] .cy-tools { display: flex; }

  .cy-nav__list {
    flex-direction: column;
    align-items: stretch;
    gap: 2px;
  }

  .cy-nav__link {
    padding: .7rem .9rem;
    border-radius: 14px;
    font-size: .9rem;
  }

  .cy-nav__link::after { display: none; }

  .cy-nav__link[aria-current="page"] {
    background: rgba(34, 211, 238, .14);
  }

  .cy-grid--2,
  .cy-grid--3,
  .cy-grid--aside {
    grid-template-columns: minmax(0, 1fr);
  }

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

@media (max-width: 640px) {
  h1 { font-size: clamp(2.25rem, 11vw, 3.25rem); }

  .cy-header__capsule {
    width: calc(100% - 1.5rem);
  }

  .cy-tools { flex-wrap: wrap; }

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

  .cy-footer__bottom {
    flex-direction: column;
    align-items: flex-start;
  }

  .cy-to-top {
    width: 42px;
    height: 42px;
  }
}

/* ---------- 21. 减少动态效果 / 打印 ---------- */
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }

  *,
  *::before,
  *::after {
    animation-duration: .001ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: .001ms !important;
  }

  .cy-reveal,
  .cy-reveal.cy-reveal--armed {
    opacity: 1 !important;
    transform: none !important;
  }

  .cy-card:hover,
  .cy-card:focus-within,
  .cy-btn:hover {
    transform: none;
  }
}

@media print {
  .cy-header,
  .cy-progress,
  .cy-to-top,
  .cy-skip { display: none !important; }
}