/* ============================================================
   legacy-bsport.com.cn · site.css
   体旧版体育共享样式 · 旧档案与新时间线
   ============================================================ */

/* ---------- 0. Reset & Tokens ---------- */
*,
*::before,
*::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

html {
  line-height: 1.5;
  -webkit-text-size-adjust: 100%;
  scroll-behavior: smooth;
  scroll-padding-top: 24px;
}

body {
  min-height: 100vh;
  background: var(--bg-base);
  color: var(--text-main);
  font-family: var(--font-body);
  line-height: 1.75;
  overflow-x: hidden;
}

ul,
ol {
  list-style: none;
}

a {
  color: var(--accent);
  text-decoration: none;
  transition: color 0.2s ease-out;
}

a:hover {
  color: #fff;
}

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

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

button {
  cursor: pointer;
}

address {
  font-style: normal;
}

h1,
h2,
h3,
h4,
h5,
h6 {
  font-family: var(--font-head);
  line-height: 1.3;
  font-weight: 800;
}

[hidden] {
  display: none !important;
}

:root {
  --bg-base: #0B1020;
  --bg-deep: #080D1A;
  --bg-panel: #0D1527;
  --accent: #00E5A0;
  --accent-2: #F5B700;
  --accent-red: #8B0000;
  --accent-blue: #1C3F60;
  --text-main: #F2F2F2;
  --text-dim: #A0A0A0;
  --border: #2A3A5E;
  --gold: #FFD700;
  --error: #FF4B4B;
  --header-w: 280px;
  --header-h: 64px;
  --font-head: 'Noto Serif SC', 'Songti SC', 'STSong', 'SimSun', serif;
  --font-body: 'Noto Sans SC', 'PingFang SC', 'Microsoft YaHei', 'Helvetica Neue', sans-serif;
  --font-data: 'JetBrains Mono', 'SF Mono', 'Cascadia Mono', 'Consolas', 'Liberation Mono', monospace;
  --ease: cubic-bezier(0.25, 0.8, 0.25, 1);
  --dur: 0.25s;
  --scanline: repeating-linear-gradient(0deg, rgba(255, 255, 255, 0.025) 0 1px, transparent 1px 4px);
}

::selection {
  background: rgba(0, 229, 160, 0.28);
  color: #fff;
}

:focus {
  outline: none;
}

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

::-webkit-scrollbar {
  width: 10px;
  height: 10px;
}

::-webkit-scrollbar-track {
  background: var(--bg-deep);
}

::-webkit-scrollbar-thumb {
  background: var(--border);
  border: 2px solid var(--bg-deep);
  border-radius: 0;
}

.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0 0 0 0);
  white-space: nowrap;
  border: 0;
}

/* ---------- 1. 头部轨道 ---------- */
.site-header {
  position: fixed;
  top: 0;
  left: 0;
  width: var(--header-w);
  height: 100vh;
  background:
    var(--scanline),
    linear-gradient(165deg, #0D1527 0%, #09101E 55%, #0B1020 100%);
  border-right: 1px solid var(--border);
  z-index: 999;
  overflow: hidden;
  display: flex;
  flex-direction: column;
}

.site-header::after {
  content: "";
  position: absolute;
  left: 0;
  right: 0;
  bottom: 0;
  height: 40px;
  background: linear-gradient(135deg, transparent 0 62%, rgba(245, 183, 0, 0.18) 63%, rgba(245, 183, 0, 0.35) 71%, transparent 72%);
  pointer-events: none;
  z-index: 3;
}

.skip-link {
  position: fixed;
  top: 10px;
  left: 10px;
  z-index: 2000;
  padding: 10px 20px;
  background: var(--accent);
  color: #001A11;
  font-weight: 700;
  font-size: 0.88rem;
  border-radius: 4px;
  transform: translateY(-300%);
  transition: transform 0.2s ease-out;
}

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

.header-rail {
  position: absolute;
  top: 50%;
  right: 2px;
  transform: translateY(-50%);
  writing-mode: vertical-rl;
  font-family: var(--font-data);
  font-size: 0.6rem;
  letter-spacing: 0.3em;
  color: rgba(160, 160, 160, 0.32);
  text-transform: uppercase;
  white-space: nowrap;
  pointer-events: none;
  user-select: none;
  z-index: 0;
}

.header-inner {
  position: relative;
  z-index: 1;
  flex: 1;
  display: flex;
  flex-direction: column;
  padding: 24px 22px 18px;
}

.brand {
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 4px 0 22px;
  border-bottom: 1px solid var(--border);
  position: relative;
}

.brand-mark {
  position: relative;
  flex: none;
  width: 46px;
  height: 46px;
  display: grid;
  place-items: center;
  background: linear-gradient(135deg, var(--accent-blue), #0d2033);
  border: 1px solid rgba(245, 183, 0, 0.7);
  clip-path: polygon(0 0, calc(100% - 8px) 0, 100% 8px, 100% 100%, 8px 100%, 0 calc(100% - 8px));
}

.brand-mark::before {
  content: "";
  position: absolute;
  inset: 0;
  background: var(--scanline);
  opacity: 0.6;
  pointer-events: none;
}

.brand-mark::after {
  content: "";
  position: absolute;
  inset: 0;
  background: linear-gradient(135deg, transparent 46%, rgba(0, 229, 160, 0.35) 47%, rgba(0, 229, 160, 0.35) 53%, transparent 54%);
  pointer-events: none;
}

.brand-mark-inner {
  position: relative;
  z-index: 1;
  font-family: var(--font-head);
  font-size: 1.2rem;
  font-weight: 900;
  color: var(--accent-2);
  line-height: 1;
}

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

.brand-name {
  font-family: var(--font-head);
  font-weight: 800;
  font-size: 1.05rem;
  color: var(--text-main);
  line-height: 1.3;
  letter-spacing: 0.02em;
}

.brand-en {
  font-family: var(--font-data);
  font-size: 0.58rem;
  color: var(--accent);
  letter-spacing: 0.18em;
  text-transform: uppercase;
  margin-top: 4px;
}

.nav-toggle {
  display: none;
}

.site-nav {
  flex: 1;
  display: flex;
  flex-direction: column;
  padding-top: 22px;
}

.nav-list {
  display: flex;
  flex-direction: column;
  gap: 4px;
}

.nav-link {
  position: relative;
  display: flex;
  align-items: baseline;
  gap: 14px;
  padding: 11px 14px;
  color: var(--text-main);
  font-size: 0.95rem;
  font-weight: 500;
  border-left: 2px solid transparent;
  transition: color var(--dur) var(--ease), background var(--dur) var(--ease), border-color var(--dur) var(--ease);
}

.nav-link::before {
  content: attr(data-index);
  font-family: var(--font-data);
  font-size: 0.68rem;
  color: var(--text-dim);
  letter-spacing: 0.05em;
}

.nav-link:hover {
  color: var(--accent);
  background: rgba(0, 229, 160, 0.06);
  border-left-color: var(--accent);
}

.nav-link[aria-current="page"] {
  color: #fff;
  background: linear-gradient(90deg, rgba(0, 229, 160, 0.14), transparent 75%);
  border-left-color: var(--accent-2);
}

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

.nav-meta {
  margin-top: auto;
  padding: 18px 14px 0;
  border-top: 1px solid var(--border);
}

.nav-meta-tag {
  display: inline-block;
  font-family: var(--font-data);
  font-size: 0.62rem;
  color: var(--accent);
  border: 1px solid rgba(0, 229, 160, 0.4);
  padding: 2px 8px;
  margin-right: 6px;
  letter-spacing: 0.08em;
}

.nav-meta-line {
  display: block;
  height: 1px;
  margin: 14px 0 10px;
  background: linear-gradient(90deg, var(--border), transparent);
}

.nav-meta-year {
  font-family: var(--font-data);
  font-size: 0.66rem;
  color: var(--text-dim);
  letter-spacing: 0.12em;
}

.header-foot {
  padding: 14px 14px 0;
}

.header-foot-icp {
  font-family: var(--font-data);
  font-size: 0.6rem;
  color: var(--text-dim);
  letter-spacing: 0.06em;
}

.header-progress {
  position: absolute;
  top: 0;
  right: 0;
  width: 3px;
  height: 100%;
  background: linear-gradient(180deg, var(--accent-2), var(--accent));
  box-shadow: 0 0 16px rgba(0, 229, 160, 0.45);
  transform: scaleY(var(--progress, 0));
  transform-origin: top;
  z-index: 4;
  pointer-events: none;
}

/* ---------- 2. 主内容与基础组件 ---------- */
.main-content {
  margin-left: var(--header-w);
  min-height: 100vh;
  padding: 40px clamp(20px, 4vw, 56px) 64px;
  position: relative;
}

.breadcrumb {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 10px;
  margin-bottom: 28px;
  font-family: var(--font-data);
  font-size: 0.75rem;
  color: var(--text-dim);
}

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

.breadcrumb a:hover {
  color: var(--accent);
}

.breadcrumb li {
  display: flex;
  align-items: center;
}

.breadcrumb li:not(:last-child)::after {
  content: "/";
  margin-left: 10px;
  color: var(--border);
  font-size: 0.85rem;
}

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

.chapter {
  display: grid;
  grid-template-columns: minmax(60px, 90px) 1fr;
  gap: clamp(18px, 3vw, 40px);
  padding: clamp(28px, 4vw, 48px) 0;
  border-bottom: 1px solid var(--border);
  scroll-margin-top: 24px;
}

.chapter-num {
  font-family: var(--font-head);
  font-size: clamp(2.4rem, 4vw, 3.8rem);
  font-weight: 900;
  color: var(--accent-2);
  line-height: 1;
  letter-spacing: -0.02em;
}

.chapter-num::after {
  content: "";
  display: block;
  width: 30px;
  height: 2px;
  background: currentColor;
  margin-top: 10px;
}

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

.section-head {
  display: flex;
  align-items: flex-start;
  gap: 14px;
  margin-bottom: 20px;
}

.section-title {
  font-family: var(--font-head);
  font-size: clamp(1.4rem, 2.5vw, 2rem);
  font-weight: 800;
  color: var(--text-main);
}

.section-annotation {
  writing-mode: vertical-rl;
  font-family: var(--font-data);
  font-size: 0.7rem;
  color: var(--accent);
  letter-spacing: 0.16em;
  text-transform: uppercase;
  line-height: 1.4;
}

.panel {
  position: relative;
  padding: clamp(20px, 3vw, 32px);
  background: linear-gradient(145deg, rgba(28, 63, 96, 0.5), rgba(28, 63, 96, 0.16));
  border: 1px solid var(--border);
  clip-path: polygon(0 0, calc(100% - 14px) 0, 100% 14px, 100% 100%, 14px 100%, 0 calc(100% - 14px));
}

.panel::before {
  content: "";
  position: absolute;
  top: 0;
  left: 0;
  width: 44px;
  height: 2px;
  background: var(--accent);
  opacity: 0.8;
}

.panel--dark {
  background: linear-gradient(145deg, rgba(139, 0, 0, 0.32), rgba(11, 16, 32, 0.85));
}

.grid-2 {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 20px;
}

.grid-3 {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 20px;
}

.grid-4 {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 16px;
}

.media-box {
  position: relative;
  aspect-ratio: 16 / 9;
  overflow: hidden;
  background: linear-gradient(145deg, rgba(28, 63, 96, 0.6), rgba(11, 16, 32, 0.9));
  border: 1px solid var(--border);
  clip-path: polygon(0 0, calc(100% - 12px) 0, 100% 12px, 100% 100%, 12px 100%, 0 calc(100% - 12px));
}

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

.media-box::after {
  content: "";
  position: absolute;
  inset: 0;
  background: var(--scanline);
  opacity: 0.5;
  pointer-events: none;
  z-index: 1;
}

.img-placeholder {
  position: absolute;
  inset: 0;
  display: grid;
  place-items: center;
  color: var(--text-dim);
  font-family: var(--font-data);
  font-size: 0.72rem;
  letter-spacing: 0.12em;
  z-index: 1;
}

.media-box--wide {
  aspect-ratio: 21 / 9;
}

.media-box--tall {
  aspect-ratio: 3 / 4;
}

.timeline {
  position: relative;
  padding-left: 28px;
}

.timeline::before {
  content: "";
  position: absolute;
  left: 8px;
  top: 6px;
  bottom: 6px;
  width: 2px;
  background: linear-gradient(180deg, var(--accent), rgba(42, 58, 94, 0.4));
}

.timeline-item {
  position: relative;
  padding: 0 0 26px 16px;
}

.timeline-dot {
  position: absolute;
  left: -25px;
  top: 4px;
  width: 12px;
  height: 12px;
  background: var(--bg-base);
  border: 2px solid var(--gold);
  transform: rotate(45deg);
}

.timeline-date {
  font-family: var(--font-data);
  font-size: 0.76rem;
  color: var(--accent);
  letter-spacing: 0.06em;
}

.timeline-content {
  margin-top: 4px;
  color: var(--text-main);
  font-size: 0.95rem;
}

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 11px 24px;
  font-family: var(--font-body);
  font-size: 0.9rem;
  font-weight: 600;
  color: var(--text-main);
  background: rgba(28, 63, 96, 0.25);
  border: 1px solid var(--border);
  transition: background var(--dur) var(--ease), border-color var(--dur) var(--ease), color var(--dur) var(--ease), box-shadow var(--dur) var(--ease);
  clip-path: polygon(0 0, calc(100% - 10px) 0, 100% 10px, 100% 100%, 10px 100%, 0 calc(100% - 10px));
}

.btn:hover {
  color: #fff;
  border-color: var(--accent);
  background: rgba(28, 63, 96, 0.45);
}

.btn--accent {
  background: var(--accent);
  border-color: var(--accent);
  color: #001A11;
}

.btn--accent:hover {
  background: #1ff0b0;
  border-color: #1ff0b0;
  color: #001A11;
  box-shadow: 0 0 24px rgba(0, 229, 160, 0.35);
}

.btn--outline {
  background: transparent;
  border-color: var(--border);
  color: var(--text-main);
}

.btn--outline:hover {
  color: var(--accent);
  border-color: var(--accent);
  background: rgba(0, 229, 160, 0.05);
}

.data-chip {
  display: inline-flex;
  align-items: center;
  padding: 3px 10px;
  font-family: var(--font-data);
  font-size: 0.74rem;
  color: var(--accent);
  background: rgba(0, 229, 160, 0.08);
  border: 1px solid rgba(0, 229, 160, 0.25);
  letter-spacing: 0.06em;
}

.tag-list {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
}

.tag-list a,
.tag-list span {
  display: inline-block;
  padding: 4px 14px;
  font-size: 0.82rem;
  color: var(--text-dim);
  border: 1px solid var(--border);
  transition: all var(--dur) var(--ease);
}

.tag-list a:hover {
  color: var(--accent);
  border-color: var(--accent);
  background: rgba(0, 229, 160, 0.06);
}

.display-title {
  font-family: var(--font-head);
  font-size: clamp(2rem, 5vw, 3.6rem);
  font-weight: 900;
  line-height: 1.15;
  color: var(--text-main);
  letter-spacing: 0.02em;
}

.lede {
  font-size: 1.05rem;
  color: var(--text-dim);
  max-width: 56ch;
  line-height: 1.8;
}

/* ---------- 3. 页脚 ---------- */
.site-footer {
  margin-left: var(--header-w);
  background: linear-gradient(180deg, var(--bg-base) 0%, var(--bg-deep) 100%);
  border-top: 1px solid var(--border);
  position: relative;
  overflow: hidden;
}

.site-footer::before {
  content: "";
  display: block;
  height: 3px;
  background: linear-gradient(90deg, var(--accent) 0%, rgba(0, 229, 160, 0.15) 28%, rgba(245, 183, 0, 0.15) 68%, var(--accent-2) 100%);
}

.footer-panel {
  padding: clamp(36px, 5vw, 64px) clamp(20px, 4vw, 56px) 20px;
}

.footer-grid {
  display: grid;
  grid-template-columns: 1.4fr 1fr 1fr 1.2fr;
  gap: clamp(24px, 4vw, 48px);
}

.footer-brand-col {
  display: flex;
  flex-direction: column;
  align-items: flex-start;
}

.footer-logo {
  display: inline-flex;
  align-items: center;
  margin-bottom: 16px;
}

.footer-logo-mark {
  display: grid;
  place-items: center;
  width: 42px;
  height: 42px;
  background: linear-gradient(135deg, var(--accent-blue), #0d2033);
  border: 1px solid rgba(245, 183, 0, 0.6);
  clip-path: polygon(0 0, calc(100% - 8px) 0, 100% 8px, 100% 100%, 8px 100%, 0 calc(100% - 8px));
  font-family: var(--font-head);
  font-weight: 900;
  font-size: 1.1rem;
  color: var(--accent-2);
}

.footer-brand-name {
  font-family: var(--font-head);
  font-size: 1.2rem;
  font-weight: 800;
  color: var(--text-main);
  margin-bottom: 4px;
}

.footer-brand-en {
  font-family: var(--font-data);
  font-size: 0.6rem;
  color: var(--accent);
  letter-spacing: 0.2em;
  text-transform: uppercase;
}

.footer-trust {
  margin-top: 16px;
  padding-top: 16px;
  border-top: 1px solid var(--border);
  color: var(--text-dim);
  font-size: 0.84rem;
  line-height: 1.7;
  max-width: 320px;
}

.footer-col-title {
  display: flex;
  align-items: center;
  gap: 10px;
  font-family: var(--font-head);
  font-size: 1rem;
  font-weight: 700;
  color: var(--text-main);
  margin-bottom: 18px;
  letter-spacing: 0.06em;
}

.footer-col-num {
  font-family: var(--font-data);
  font-size: 0.66rem;
  color: var(--accent-2);
  border: 1px solid rgba(245, 183, 0, 0.35);
  padding: 2px 6px;
}

.footer-links {
  display: grid;
  gap: 9px;
}

.footer-links a {
  color: var(--text-dim);
  font-size: 0.88rem;
  padding-left: 16px;
  position: relative;
  transition: color var(--dur) var(--ease), padding-left var(--dur) var(--ease);
}

.footer-links a::before {
  content: "→";
  position: absolute;
  left: 0;
  top: 0;
  color: var(--accent);
  opacity: 0.7;
  font-family: var(--font-data);
  font-size: 0.8rem;
}

.footer-links a:hover {
  color: var(--accent);
  padding-left: 20px;
}

.footer-address {
  display: grid;
  gap: 10px;
  color: var(--text-dim);
  font-size: 0.84rem;
  line-height: 1.65;
}

.footer-address-item {
  display: block;
}

.footer-marquee {
  margin-top: 36px;
  padding: 12px 0;
  border-top: 1px solid var(--border);
  border-bottom: 1px solid var(--border);
  overflow: hidden;
  white-space: nowrap;
  position: relative;
}

.footer-marquee span {
  display: inline-block;
  font-family: var(--font-data);
  font-size: 0.7rem;
  color: var(--text-dim);
  letter-spacing: 0.18em;
  text-transform: uppercase;
  animation: marquee 28s linear infinite;
}

@keyframes marquee {
  from {
    transform: translateX(0);
  }
  to {
    transform: translateX(-50%);
  }
}

.footer-bottom {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 10px 28px;
  padding: 20px 0 8px;
  font-family: var(--font-data);
  font-size: 0.7rem;
  color: var(--text-dim);
}

.footer-copy {
  color: var(--text-dim);
}

.footer-icp {
  letter-spacing: 0.1em;
}

.footer-address-short {
  margin-left: auto;
}

/* ---------- 4. 返回顶部 ---------- */
.back-top {
  position: fixed;
  right: 28px;
  bottom: 28px;
  z-index: 950;
  display: flex;
  align-items: center;
  gap: 8px;
  padding: 12px 18px;
  background: rgba(13, 21, 39, 0.92);
  border: 1px solid var(--border);
  color: var(--accent);
  font-family: var(--font-data);
  font-size: 0.7rem;
  letter-spacing: 0.1em;
  backdrop-filter: blur(8px);
  transition: border-color var(--dur) var(--ease), color var(--dur) var(--ease), box-shadow var(--dur) var(--ease);
  clip-path: polygon(0 0, calc(100% - 10px) 0, 100% 10px, 100% 100%, 10px 100%, 0 calc(100% - 10px));
  cursor: pointer;
}

.back-top:hover {
  color: #fff;
  border-color: var(--accent);
  box-shadow: 0 0 20px rgba(0, 229, 160, 0.35);
}

.back-top-icon {
  flex: none;
}

.back-top-text {
  line-height: 1;
}

/* ---------- 5. 响应式 ---------- */
@media (max-height: 700px) and (min-width: 1024px) {
  .site-header {
    overflow-y: auto;
  }
}

@media (max-width: 1279px) and (min-width: 1024px) {
  .footer-grid {
    grid-template-columns: 1fr 1fr;
  }

  .footer-trust {
    max-width: 100%;
  }
}

@media (max-width: 1023px) {
  .site-header {
    position: sticky;
    top: 0;
    left: 0;
    width: 100%;
    height: var(--header-h);
    min-height: 0;
    border-right: 0;
    border-bottom: 1px solid var(--border);
    flex-direction: row;
    align-items: center;
    overflow: visible;
  }

  .site-header::after {
    display: none;
  }

  .header-inner {
    flex: 1;
    flex-direction: row;
    align-items: center;
    flex-wrap: nowrap;
    padding: 0 16px;
    width: 100%;
  }

  .brand {
    flex: 1;
    border-bottom: 0;
    padding: 10px 0;
    gap: 10px;
  }

  .brand-mark {
    width: 40px;
    height: 40px;
  }

  .brand-mark-inner {
    font-size: 1rem;
  }

  .brand-name {
    font-size: 0.95rem;
  }

  .brand-en {
    font-size: 0.52rem;
  }

  .header-rail {
    display: none;
  }

  .nav-toggle {
    display: inline-flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    gap: 2px;
    width: 48px;
    height: 48px;
    background: rgba(28, 63, 96, 0.25);
    border: 1px solid var(--border);
    color: var(--text-main);
    margin-left: 8px;
  }

  .nav-toggle-box {
    display: flex;
    flex-direction: column;
    gap: 3px;
    align-items: center;
  }

  .nav-toggle-line {
    display: block;
    width: 20px;
    height: 2px;
    background: currentColor;
    transition: transform 0.25s var(--ease), opacity 0.25s var(--ease);
  }

  .nav-toggle-text {
    font-size: 0.52rem;
    color: var(--text-dim);
    line-height: 1;
    margin-top: 2px;
  }

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

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

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

  .site-nav {
    position: fixed;
    top: var(--header-h);
    left: 0;
    bottom: 0;
    width: min(380px, 88vw);
    padding: 32px 24px;
    background: linear-gradient(180deg, rgba(13, 21, 39, 0.98), rgba(9, 16, 30, 0.99));
    border-right: 1px solid var(--border);
    box-shadow: 12px 0 36px rgba(0, 0, 0, 0.45);
    transform: translateX(-110%);
    visibility: hidden;
    transition: transform 0.3s var(--ease), visibility 0s linear 0.3s;
    overflow-y: auto;
    z-index: 998;
  }

  .site-nav[data-open] {
    transform: translateX(0);
    visibility: visible;
    transition: transform 0.3s var(--ease), visibility 0s linear 0s;
  }

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

  body[data-nav-open]::after {
    content: "";
    position: fixed;
    inset: 0;
    background: rgba(5, 8, 18, 0.62);
    backdrop-filter: blur(2px);
    z-index: 997;
  }

  .header-progress {
    top: auto;
    right: auto;
    bottom: 0;
    left: 0;
    width: 100%;
    height: 3px;
    background: linear-gradient(90deg, var(--accent), var(--accent-2));
    box-shadow: 0 -2px 12px rgba(0, 229, 160, 0.35);
    transform: scaleX(var(--progress, 0));
    transform-origin: left;
  }

  .main-content {
    margin-left: 0;
    padding: 28px 18px 52px;
  }

  .site-footer {
    margin-left: 0;
  }

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

  .footer-address-short {
    margin-left: 0;
  }

  .back-top {
    right: 16px;
    bottom: 16px;
  }
}

@media (max-width: 767px) {
  .grid-2,
  .grid-3,
  .grid-4 {
    grid-template-columns: 1fr;
  }

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

  .footer-bottom {
    justify-content: flex-start;
  }

  .footer-address-short {
    width: 100%;
    margin-left: 0;
  }

  .chapter {
    grid-template-columns: 1fr;
    gap: 12px;
  }

  .chapter-num {
    font-size: 2.2rem;
  }

  .display-title {
    font-size: 2rem;
  }

  .section-head {
    flex-wrap: wrap;
  }

  .brand-en {
    display: none;
  }
}

/* ---------- 6. 无障碍与降级 ---------- */
@media (prefers-reduced-motion: reduce) {
  html {
    scroll-behavior: auto;
  }

  .footer-marquee span {
    animation: none;
  }

  *,
  *::before,
  *::after {
    transition-duration: 0.01ms !important;
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
  }
}