/* ==========================================================================
   博鱼综合体育 — 全站共享样式 /assets/site.css
   水下竞技场视觉系统：深海底色 + 水波漂移 + 荧光青线索 + 珊瑚橙唯一行动色
   ========================================================================== */

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

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

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

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

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

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

button { background: none; border: 0; }

a { color: inherit; }

/* ---------- 2. 设计变量 ---------- */
:root {
  /* 色彩体系 */
  --abyss: #05131F;      /* 深海脊线 */
  --deep: #0A2233;       /* 深水蓝 */
  --mid: #123A52;        /* 中层水色 */
  --cyan: #2FE3D2;       /* 荧光青 */
  --mint: #A8F0E8;       /* 浅青雾 */
  --coral: #FF6B4A;      /* 珊瑚橙 */
  --gold: #FFD166;       /* 光线金 */
  --sand: #F3F8FA;       /* 沙白 */
  --ink: #0C2233;        /* 墨蓝正文 */
  --muted: #8DA7B8;      /* 灰蓝注释 */

  /* 半透明派生 */
  --cyan-06: rgba(47, 227, 210, .06);
  --cyan-10: rgba(47, 227, 210, .10);
  --cyan-18: rgba(47, 227, 210, .18);
  --cyan-32: rgba(47, 227, 210, .32);
  --coral-10: rgba(255, 107, 74, .10);
  --coral-30: rgba(255, 107, 74, .30);
  --gold-10: rgba(255, 209, 102, .10);
  --ink-70: rgba(243, 248, 250, .70);
  --ink-55: rgba(243, 248, 250, .55);

  /* 边界与圆角 */
  --line: 1px solid var(--cyan-18);
  --line-strong: 1px solid var(--cyan-32);
  --r-sm: 10px;
  --r-md: 16px;
  --r-lg: 20px;
  --r-pill: 999px;

  /* 阴影 */
  --shadow-soft: 0 8px 26px rgba(2, 10, 18, .45);
  --shadow-float: 0 18px 48px rgba(2, 10, 18, .60);

  /* 字体 */
  --font-display: "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "Helvetica Neue", Arial, sans-serif;
  --font-serif: "Songti SC", "Times New Roman", Georgia, serif;
  --font-mono: "SF Mono", "JetBrains Mono", "Roboto Mono", Menlo, Consolas, "Courier New", monospace;

  /* 尺度 */
  --container: 1240px;
  --gutter: clamp(1rem, 4vw, 3rem);
  --header-h: 74px;
}

/* ---------- 3. 基础排版 ---------- */
body {
  min-height: 100vh;
  background-color: var(--abyss);
  color: var(--sand);
  font-family: var(--font-display);
  font-size: 16px;
  line-height: 1.65;
  letter-spacing: .01em;
  overflow-x: hidden;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  text-rendering: optimizeLegibility;
}

/* 水下光斑层 */
body::before {
  content: "";
  position: fixed;
  inset: -18%;
  z-index: 0;
  pointer-events: none;
  background:
    radial-gradient(ellipse 46% 40% at 12% 6%, rgba(47, 227, 210, .12), transparent 62%),
    radial-gradient(ellipse 40% 34% at 84% 18%, rgba(255, 107, 74, .08), transparent 60%),
    radial-gradient(ellipse 52% 40% at 56% 92%, rgba(168, 240, 232, .07), transparent 64%);
  animation: bx-caustic 24s ease-in-out infinite alternate;
}

/* 斜向水纹层 */
body::after {
  content: "";
  position: fixed;
  inset: 0;
  z-index: 0;
  pointer-events: none;
  background-image:
    repeating-linear-gradient(115deg, rgba(47, 227, 210, .035) 0 1px, transparent 1px 22px),
    repeating-linear-gradient(65deg, rgba(168, 240, 232, .022) 0 1px, transparent 1px 34px);
  opacity: .9;
}

@keyframes bx-caustic {
  0%   { transform: translate3d(-1.5%, -1%, 0) scale(1); }
  50%  { transform: translate3d(1.5%, 1.4%, 0) scale(1.04); }
  100% { transform: translate3d(-.8%, 2%, 0) scale(1.02); }
}

h1, h2, h3, h4, h5, h6 {
  font-weight: 700;
  line-height: 1.16;
  letter-spacing: -.02em;
}

p { margin-bottom: 0; }

strong, b { font-weight: 700; }

::selection {
  background: var(--cyan);
  color: var(--abyss);
}

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

.bx-btn:focus-visible,
.bx-nav-link:focus-visible,
.bx-copy:focus-visible,
.bx-totop:focus-visible,
.bx-nav-toggle:focus-visible {
  outline: 2px solid var(--cyan);
  outline-offset: 4px;
}

/* ---------- 4. 布局骨架 ---------- */
.bx-container {
  position: relative;
  z-index: 1;
  width: 100%;
  max-width: var(--container);
  margin-inline: auto;
  padding-inline: var(--gutter);
}

.bx-main {
  position: relative;
  z-index: 1;
  padding-top: clamp(5.8rem, 10vw, 7.6rem);
}

.bx-section {
  position: relative;
  z-index: 1;
  padding-block: clamp(2.6rem, 6vw, 5rem);
}

.bx-prose {
  max-width: 40em;
  line-height: 1.75;
}

.bx-prose p { margin-bottom: 1.1em; }

.bx-prose p:last-child { margin-bottom: 0; }

/* ---------- 5. SKIP LINK ---------- */
.bx-skip {
  position: fixed;
  top: -120px;
  left: 50%;
  transform: translateX(-50%);
  z-index: 999;
  padding: .72rem 1.4rem;
  border-radius: 0 0 14px 14px;
  background: var(--cyan);
  color: var(--abyss);
  font-size: .9rem;
  font-weight: 700;
  letter-spacing: .04em;
  text-decoration: none;
  box-shadow: 0 12px 28px rgba(47, 227, 210, .34);
  transition: top .22s ease;
}

.bx-skip:focus-visible,
.bx-skip:focus {
  top: 0;
  outline-offset: -4px;
}

/* ---------- 6. HEADER ---------- */
.bx-header {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 80;
  padding: clamp(.55rem, 1.6vw, 1rem) var(--gutter) 0;
  pointer-events: none;
}

.bx-capsule {
  pointer-events: auto;
  position: relative;
  display: flex;
  align-items: center;
  gap: clamp(.5rem, 1.4vw, 1.3rem);
  width: 100%;
  max-width: var(--container);
  margin-inline: auto;
  padding: .48rem .5rem .48rem .95rem;
  border-radius: var(--r-pill);
  border: 1px solid rgba(47, 227, 210, .22);
  background: rgba(10, 34, 51, .74);
  -webkit-backdrop-filter: blur(16px) saturate(150%);
  backdrop-filter: blur(16px) saturate(150%);
  box-shadow:
    0 12px 34px rgba(2, 10, 18, .52),
    inset 0 1px 0 rgba(168, 240, 232, .10);
  transition: padding .26s ease, background-color .26s ease, box-shadow .26s ease;
}

.bx-header[data-stuck="true"] .bx-capsule {
  padding: .3rem .38rem .3rem .9rem;
  background: rgba(5, 19, 31, .86);
  box-shadow:
    0 10px 30px rgba(2, 10, 18, .64),
    inset 0 1px 0 rgba(168, 240, 232, .08);
}

/* 品牌 */
.bx-brand {
  display: flex;
  align-items: center;
  gap: .6rem;
  flex: 0 0 auto;
  text-decoration: none;
  color: var(--sand);
  padding: .18rem .1rem;
}

.bx-brand-mark {
  position: relative;
  flex: 0 0 auto;
  width: 30px;
  height: 30px;
  border-radius: 10px;
  background: linear-gradient(152deg, var(--cyan) 0%, #1A93A0 58%, #0B4A5C 100%);
  box-shadow:
    inset 0 0 0 1px rgba(5, 19, 31, .45),
    0 0 16px rgba(47, 227, 210, .38);
  overflow: hidden;
}

.bx-brand-mark::after {
  content: "";
  position: absolute;
  inset: 0;
  background: repeating-linear-gradient(118deg, transparent 0 4px, rgba(5, 19, 31, .38) 4px 5px);
}

.bx-brand-text {
  display: flex;
  flex-direction: column;
  line-height: 1.15;
}

.bx-brand-name {
  font-size: 1rem;
  font-weight: 800;
  letter-spacing: .01em;
  color: var(--sand);
  white-space: nowrap;
}

.bx-brand-badge {
  font-size: .62rem;
  letter-spacing: .14em;
  color: var(--mint);
  white-space: nowrap;
  opacity: .85;
}

/* 章节指示 */
.bx-chapter {
  display: none;
  font-family: var(--font-serif);
  font-size: .8rem;
  letter-spacing: .16em;
  color: var(--mint);
  padding-left: .85rem;
  border-left: 1px solid rgba(47, 227, 210, .28);
  max-width: 15ch;
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}

.bx-header[data-stuck="true"] .bx-chapter:not(:empty) {
  display: inline-block;
}

/* 主导航 */
.bx-nav {
  display: flex;
  align-items: center;
  margin-left: auto;
}

.bx-nav-list {
  display: flex;
  align-items: center;
  gap: .1rem;
}

.bx-nav-link {
  display: inline-block;
  padding: .46rem .78rem;
  border-radius: var(--r-pill);
  border: 1px solid transparent;
  color: var(--ink-70);
  font-size: .92rem;
  font-weight: 500;
  text-decoration: none;
  white-space: nowrap;
  transition: color .18s ease, background-color .18s ease, border-color .18s ease;
}

.bx-nav-link:hover {
  color: var(--mint);
  background: var(--cyan-10);
  border-color: rgba(47, 227, 210, .22);
}

.bx-nav-link[aria-current="page"] {
  color: var(--abyss);
  font-weight: 700;
  background: linear-gradient(180deg, var(--cyan) 0%, #22C6B7 100%);
  border-color: rgba(47, 227, 210, .55);
  box-shadow: 0 6px 18px rgba(47, 227, 210, .26);
}

.bx-nav-link[aria-current="page"]:hover {
  color: var(--abyss);
  background: linear-gradient(180deg, var(--mint) 0%, var(--cyan) 100%);
}

/* 移动折叠按钮 */
.bx-nav-toggle {
  display: none;
  align-items: center;
  gap: .45rem;
  margin-left: auto;
  padding: .5rem .85rem;
  border-radius: var(--r-pill);
  border: 1px solid rgba(47, 227, 210, .30);
  background: var(--cyan-06);
  color: var(--mint);
  font-size: .84rem;
  letter-spacing: .1em;
  cursor: pointer;
  transition: background-color .18s ease, border-color .18s ease;
}

.bx-nav-toggle:hover { background: var(--cyan-10); }

.bx-toggle-bars {
  display: inline-flex;
  flex-direction: column;
  gap: 3px;
  width: 16px;
}

.bx-toggle-bars span {
  display: block;
  height: 2px;
  border-radius: 2px;
  background: currentColor;
  transition: transform .24s ease, opacity .18s ease;
}

.bx-nav-toggle[aria-expanded="true"] {
  background: var(--coral-10);
  border-color: rgba(255, 107, 74, .45);
  color: var(--coral);
}

.bx-nav-toggle[aria-expanded="true"] .bx-toggle-bars span:nth-child(1) {
  transform: translateY(5px) rotate(45deg);
}

.bx-nav-toggle[aria-expanded="true"] .bx-toggle-bars span:nth-child(2) {
  opacity: 0;
}

.bx-nav-toggle[aria-expanded="true"] .bx-toggle-bars span:nth-child(3) {
  transform: translateY(-5px) rotate(-45deg);
}

/* 滚动进度条 */
.bx-progress {
  position: absolute;
  left: 0;
  right: 0;
  bottom: -1px;
  height: 2px;
  overflow: hidden;
  background: rgba(47, 227, 210, .08);
}

.bx-progress-bar {
  display: block;
  height: 100%;
  width: 0;
  background: linear-gradient(90deg, var(--cyan) 0%, var(--mint) 55%, var(--coral) 100%);
  box-shadow: 0 0 14px rgba(47, 227, 210, .70);
  transition: width .12s linear;
}

/* ---------- 7. 按钮 ---------- */
.bx-btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: .45rem;
  padding: .7rem 1.32rem;
  border-radius: var(--r-pill);
  border: 1px solid transparent;
  font-family: inherit;
  font-size: .92rem;
  font-weight: 700;
  letter-spacing: .03em;
  line-height: 1.2;
  text-decoration: none;
  cursor: pointer;
  white-space: nowrap;
  transition: transform .18s ease, box-shadow .18s ease, background-color .18s ease, color .18s ease;
}

.bx-btn--coral {
  color: #220B05;
  background: linear-gradient(135deg, #FF8A6B 0%, var(--coral) 72%);
  box-shadow:
    0 10px 26px rgba(255, 107, 74, .30),
    inset 0 1px 0 rgba(255, 255, 255, .30);
}

.bx-btn--coral:hover {
  transform: translateY(-2px);
  box-shadow:
    0 16px 34px rgba(255, 107, 74, .44),
    inset 0 1px 0 rgba(255, 255, 255, .34);
}

.bx-btn--coral:active { transform: translateY(0); }

.bx-btn--ghost {
  color: var(--mint);
  border-color: var(--cyan-32);
  background: var(--cyan-06);
}

.bx-btn--ghost:hover {
  color: var(--abyss);
  background: var(--cyan);
  border-color: var(--cyan);
}

.bx-capsule-cta {
  flex: 0 0 auto;
  padding: .62rem 1.15rem;
  font-size: .88rem;
}

/* ---------- 8. 通用排版组件 ---------- */
.bx-eyebrow {
  display: inline-flex;
  align-items: center;
  gap: .6rem;
  font-family: var(--font-serif);
  font-size: .9rem;
  font-weight: 400;
  letter-spacing: .18em;
  text-transform: uppercase;
  color: var(--cyan);
  margin-bottom: .9rem;
}

.bx-eyebrow::before {
  content: "";
  width: 1.7rem;
  height: 1px;
  background: currentColor;
  opacity: .75;
}

.bx-title {
  font-size: clamp(2.2rem, 5.4vw, 4.4rem);
  font-weight: 800;
  line-height: 1.05;
  letter-spacing: -.02em;
  color: var(--sand);
  margin-bottom: .55em;
}

.bx-subtitle {
  font-size: clamp(1rem, 1.55vw, 1.16rem);
  line-height: 1.72;
  color: var(--ink-70);
  max-width: 38ch;
}

.bx-num {
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  font-feature-settings: "tnum" 1;
  letter-spacing: .01em;
}

.bx-meta {
  font-size: .78rem;
  line-height: 1.5;
  letter-spacing: .06em;
  color: var(--muted);
}

/* 表面卡片 */
.bx-surface {
  position: relative;
  border: var(--line);
  border-radius: var(--r-lg);
  background: linear-gradient(158deg, rgba(18, 58, 82, .80) 0%, rgba(10, 34, 51, .74) 100%);
  box-shadow: var(--shadow-soft);
  overflow: hidden;
}

/* 浅色长文分区 */
.bx-light {
  background: var(--sand);
  color: var(--ink);
}

.bx-light .bx-title { color: var(--ink); }
.bx-light .bx-subtitle { color: #40586A; }
.bx-light .bx-eyebrow { color: #0E7C77; }
.bx-light .bx-meta { color: #5D7889; }
.bx-light .bx-prose { color: #16334A; }

/* 标签 */
.bx-tag {
  display: inline-flex;
  align-items: center;
  gap: .34rem;
  padding: .18rem .62rem;
  border-radius: var(--r-pill);
  border: 1px solid rgba(47, 227, 210, .30);
  background: var(--cyan-06);
  color: var(--mint);
  font-size: .72rem;
  letter-spacing: .1em;
  line-height: 1.6;
  white-space: nowrap;
}

.bx-tag--gold {
  border-color: rgba(255, 209, 102, .42);
  background: var(--gold-10);
  color: var(--gold);
}

.bx-tag--coral {
  border-color: rgba(255, 107, 74, .44);
  background: var(--coral-10);
  color: var(--coral);
}

/* ---------- 9. 面包屑 ---------- */
.bx-breadcrumb {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: .42rem;
  margin-bottom: 1.5rem;
  font-size: .78rem;
  letter-spacing: .07em;
  color: var(--muted);
}

.bx-breadcrumb li {
  display: inline-flex;
  align-items: center;
  gap: .42rem;
}

.bx-breadcrumb li + li::before {
  content: "/";
  color: rgba(141, 167, 184, .45);
}

.bx-breadcrumb a {
  color: var(--mint);
  text-decoration: none;
  border-bottom: 1px solid transparent;
  transition: border-color .18s ease, color .18s ease;
}

.bx-breadcrumb a:hover {
  color: var(--cyan);
  border-bottom-color: currentColor;
}

.bx-breadcrumb [aria-current="page"] {
  color: var(--sand);
}

.bx-light .bx-breadcrumb { color: #5D7889; }
.bx-light .bx-breadcrumb a { color: #0E7C77; }
.bx-light .bx-breadcrumb [aria-current="page"] { color: var(--ink); }

/* ---------- 10. 网格 ---------- */
.bx-grid {
  display: grid;
  gap: clamp(1rem, 2.4vw, 2rem);
}

.bx-grid--2 { grid-template-columns: repeat(2, minmax(0, 1fr)); }
.bx-grid--3 { grid-template-columns: repeat(3, minmax(0, 1fr)); }
.bx-grid--auto { grid-template-columns: repeat(auto-fit, minmax(min(100%, 260px), 1fr)); }

/* ---------- 11. 图片容器基础规则 ---------- */
.bx-media {
  position: relative;
  display: block;
  width: 100%;
  border: var(--line);
  border-radius: var(--r-lg);
  overflow: hidden;
  isolation: isolate;
  background:
    radial-gradient(circle at 28% 18%, rgba(47, 227, 210, .24), transparent 58%),
    radial-gradient(circle at 76% 96%, rgba(255, 107, 74, .18), transparent 62%),
    linear-gradient(158deg, #16435C 0%, #0A2233 52%, #05131F 100%);
  box-shadow: var(--shadow-soft);
}

.bx-media::after {
  content: "";
  position: absolute;
  inset: 0;
  pointer-events: none;
  background-image:
    repeating-linear-gradient(118deg, rgba(168, 240, 232, .075) 0 1px, transparent 1px 17px),
    repeating-linear-gradient(62deg, rgba(168, 240, 232, .045) 0 1px, transparent 1px 29px);
}

.bx-media--wide { aspect-ratio: 16 / 9; }
.bx-media--tall { aspect-ratio: 3 / 4; }
.bx-media--square { aspect-ratio: 1 / 1; }

.bx-media__img {
  display: block;
  width: 100%;
  height: 100%;
  object-fit: cover;
}

.bx-media__caption {
  position: absolute;
  left: .85rem;
  right: .85rem;
  bottom: .8rem;
  z-index: 2;
  font-size: .74rem;
  letter-spacing: .07em;
  color: var(--mint);
  text-shadow: 0 1px 8px rgba(5, 19, 31, .9);
}

/* ---------- 12. FOOTER ---------- */
.bx-footer {
  position: relative;
  z-index: 1;
  margin-top: clamp(3rem, 7vw, 6rem);
  padding: clamp(2.4rem, 5vw, 4rem) 0 2rem;
  border-top: 1px solid rgba(47, 227, 210, .18);
  background:
    radial-gradient(ellipse 60% 90% at 82% 0%, rgba(47, 227, 210, .09), transparent 62%),
    linear-gradient(180deg, rgba(5, 19, 31, .30) 0%, var(--abyss) 46%);
  color: var(--muted);
}

.bx-footer-grid {
  display: grid;
  grid-template-columns: 1.5fr repeat(3, minmax(120px, 1fr));
  gap: clamp(1.5rem, 3vw, 2.8rem);
  padding-bottom: clamp(1.6rem, 3vw, 2.4rem);
  border-bottom: 1px solid rgba(47, 227, 210, .12);
}

.bx-footer-brand {
  display: flex;
  flex-direction: column;
  align-items: flex-start;
  gap: .5rem;
}

.bx-footer-wordmark {
  font-size: 1.28rem;
  font-weight: 800;
  letter-spacing: .01em;
  color: var(--sand);
  line-height: 1.2;
}

.bx-footer-version {
  font-size: .68rem;
  letter-spacing: .16em;
  color: var(--cyan);
}

.bx-footer-tagline {
  margin-top: .3rem;
  max-width: 24ch;
  font-size: .9rem;
  line-height: 1.7;
  color: var(--ink-55);
}

.bx-footer-chips {
  display: flex;
  flex-wrap: wrap;
  gap: .4rem;
  margin-top: .8rem;
}

.bx-footer-chips li {
  padding: .14rem .56rem;
  border: 1px solid rgba(47, 227, 210, .24);
  border-radius: var(--r-pill);
  font-family: var(--font-serif);
  font-size: .68rem;
  letter-spacing: .18em;
  color: var(--mint);
}

.bx-footer-heading {
  margin-bottom: .9rem;
  font-family: var(--font-serif);
  font-size: .78rem;
  font-weight: 400;
  letter-spacing: .2em;
  text-transform: uppercase;
  color: var(--mint);
}

.bx-footer-list {
  display: flex;
  flex-direction: column;
  gap: .55rem;
}

.bx-footer-list a {
  display: inline-block;
  font-size: .92rem;
  color: var(--ink-70);
  text-decoration: none;
  background-image: linear-gradient(var(--cyan), var(--cyan));
  background-repeat: no-repeat;
  background-position: 0 100%;
  background-size: 0% 1px;
  transition: color .18s ease, background-size .26s ease;
}

.bx-footer-list a:hover {
  color: var(--cyan);
  background-size: 100% 1px;
}

/* 联系区 */
.bx-footer-contact {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(min(100%, 260px), 1fr));
  gap: .7rem clamp(1rem, 2.4vw, 2.4rem);
  padding-block: clamp(1.4rem, 3vw, 2rem);
  border-bottom: 1px solid rgba(47, 227, 210, .12);
}

.bx-contact-line {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: .5rem;
  font-size: .88rem;
}

.bx-contact-label {
  font-family: var(--font-serif);
  font-size: .72rem;
  letter-spacing: .16em;
  color: var(--mint);
  opacity: .85;
}

.bx-contact-value {
  color: rgba(243, 248, 250, .84);
  word-break: break-all;
}

.bx-copy {
  padding: .1rem .5rem;
  border-radius: var(--r-pill);
  border: 1px solid rgba(47, 227, 210, .28);
  background: var(--cyan-06);
  color: var(--mint);
  font-size: .7rem;
  letter-spacing: .08em;
  cursor: pointer;
  transition: background-color .18s ease, color .18s ease, border-color .18s ease;
}

.bx-copy:hover {
  background: var(--cyan-18);
  border-color: var(--cyan-32);
  color: #fff;
}

.bx-copy[data-copied="true"] {
  border-color: rgba(255, 209, 102, .5);
  background: var(--gold-10);
  color: var(--gold);
}

.bx-service-note {
  grid-column: 1 / -1;
  max-width: 60ch;
  font-size: .78rem;
  line-height: 1.75;
  color: rgba(141, 167, 184, .82);
}

/* 法律条 */
.bx-footer-legal {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: .6rem 1.2rem;
  padding-top: 1.2rem;
}

.bx-legal-line {
  font-size: .76rem;
  letter-spacing: .06em;
  color: rgba(141, 167, 184, .82);
}

/* 返回顶部 */
.bx-totop {
  position: fixed;
  right: clamp(.8rem, 3vw, 1.6rem);
  bottom: clamp(.8rem, 3vw, 1.6rem);
  z-index: 55;
  display: inline-flex;
  align-items: center;
  gap: .4rem;
  padding: .62rem 1.05rem;
  border-radius: var(--r-pill);
  border: 1px solid rgba(47, 227, 210, .32);
  background: rgba(10, 34, 51, .88);
  -webkit-backdrop-filter: blur(12px);
  backdrop-filter: blur(12px);
  color: var(--mint);
  font-size: .8rem;
  letter-spacing: .08em;
  cursor: pointer;
  opacity: 0;
  visibility: hidden;
  transform: translateY(10px);
  transition: opacity .24s ease, transform .24s ease, visibility .24s ease, background-color .18s ease;
  box-shadow: var(--shadow-soft);
}

.bx-totop[data-visible="true"] {
  opacity: 1;
  visibility: visible;
  transform: none;
}

.bx-totop:hover {
  background: var(--cyan);
  color: var(--abyss);
}

/* ---------- 13. 显现动效协议 ---------- */
[data-reveal] {
  opacity: 0;
  transform: translateY(12px);
  transition: opacity .5s ease, transform .5s cubic-bezier(.22, .9, .28, 1);
}

[data-reveal][data-revealed="true"] {
  opacity: 1;
  transform: none;
}

/* ---------- 14. 响应式 ---------- */
@media (max-width: 1080px) {
  .bx-nav-link {
    padding: .44rem .62rem;
    font-size: .88rem;
  }
  .bx-capsule-cta {
    padding: .58rem .95rem;
    font-size: .84rem;
  }
}

@media (max-width: 960px) {
  .bx-header {
    padding-top: .5rem;
  }

  .bx-capsule {
    padding: .4rem .42rem .4rem .72rem;
    gap: .5rem;
  }

  .bx-brand-badge { display: none; }
  .bx-brand-name { font-size: .95rem; }

  .bx-chapter { display: none !important; }

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

  .bx-nav {
    position: fixed;
    left: 50%;
    bottom: calc(.85rem + env(safe-area-inset-bottom, 0px));
    width: min(560px, calc(100vw - 1.5rem));
    margin-left: 0;
    padding: .7rem;
    flex-direction: column;
    align-items: stretch;
    gap: .15rem;
    border: 1px solid rgba(47, 227, 210, .28);
    border-radius: var(--r-lg);
    background: rgba(8, 28, 42, .96);
    -webkit-backdrop-filter: blur(18px) saturate(150%);
    backdrop-filter: blur(18px) saturate(150%);
    box-shadow: var(--shadow-float);
    transform: translate(-50%, 150%);
    opacity: 0;
    pointer-events: none;
    visibility: hidden;
    z-index: 90;
    transition: transform .3s cubic-bezier(.22, .9, .28, 1), opacity .24s ease, visibility .3s;
  }

  .bx-nav[data-open="true"] {
    transform: translate(-50%, 0);
    opacity: 1;
    pointer-events: auto;
    visibility: visible;
  }

  .bx-nav-list {
    flex-direction: column;
    align-items: stretch;
    gap: .15rem;
  }

  .bx-nav-link {
    display: block;
    padding: .78rem .9rem;
    font-size: 1rem;
    border-radius: var(--r-sm);
  }

  .bx-nav-link[aria-current="page"] {
    border-radius: var(--r-sm);
  }

  body[data-nav-open="true"] {
    overflow: hidden;
  }

  .bx-capsule-cta {
    padding: .58rem .9rem;
    font-size: .84rem;
  }

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

  .bx-footer-brand {
    grid-column: 1 / -1;
  }

  .bx-footer-tagline { max-width: 34ch; }

  .bx-grid--2,
  .bx-grid--3 {
    grid-template-columns: 1fr;
  }
}

@media (max-width: 560px) {
  .bx-brand-name { font-size: .9rem; }

  .bx-capsule-cta {
    padding: .52rem .78rem;
    font-size: .8rem;
  }

  .bx-nav-toggle {
    padding: .46rem .7rem;
    font-size: .78rem;
  }

  .bx-toggle-text { display: none; }

  .bx-footer-grid {
    grid-template-columns: 1fr;
    gap: 1.6rem;
  }

  .bx-footer-legal {
    flex-direction: column;
    align-items: flex-start;
  }

  .bx-totop {
    bottom: calc(4.6rem + env(safe-area-inset-bottom, 0px));
  }
}

/* ---------- 15. 无障碍：减弱动效 ---------- */
@media (prefers-reduced-motion: reduce) {
  html {
    scroll-behavior: auto;
  }

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

  body::before {
    animation: none;
  }

  [data-reveal],
  [data-reveal][data-revealed="true"] {
    opacity: 1;
    transform: none;
  }

  .bx-btn--coral:hover {
    transform: none;
  }
}