.page-disclaimer {
  --ud-accent: var(--cyan);
  --ud-body-text: #C3CCE6;
  position: relative;
  isolation: isolate;
  overflow-x: hidden;
  padding-block-start: clamp(96px, 12vw, 148px);
  padding-block-end: clamp(56px, 8vw, 96px);
  background:
    radial-gradient(120% 60% at 12% -10%, rgba(46, 230, 222, 0.10), transparent 60%),
    radial-gradient(90% 50% at 92% 4%, rgba(255, 62, 157, 0.08), transparent 62%),
    var(--bg);
  color: var(--ink);
  font-family: var(--font-body);
}

.page-disclaimer::before {
  content: "";
  position: absolute;
  inset: 0 0 auto 0;
  height: 720px;
  z-index: 0;
  pointer-events: none;
  background-image:
    linear-gradient(rgba(37, 48, 79, 0.42) 1px, transparent 1px),
    linear-gradient(90deg, rgba(37, 48, 79, 0.42) 1px, transparent 1px);
  background-size: 72px 72px;
  -webkit-mask-image: linear-gradient(180deg, rgba(0, 0, 0, 0.85), transparent 78%);
  mask-image: linear-gradient(180deg, rgba(0, 0, 0, 0.85), transparent 78%);
  opacity: 0.6;
}

.page-disclaimer > * {
  position: relative;
  z-index: 1;
}

/* 面包屑微调 */
.page-disclaimer .breadcrumb ol {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin: 0 0 clamp(20px, 3vw, 32px);
  padding: 0;
  list-style: none;
  font-size: 13px;
  color: var(--muted);
}

.page-disclaimer .breadcrumb li + li::before {
  content: "/";
  margin-inline-end: 8px;
  color: var(--line);
}

.page-disclaimer .breadcrumb a {
  color: var(--muted);
  text-decoration: none;
  border-bottom: 1px solid transparent;
  transition: color 180ms var(--ease), border-color 180ms var(--ease);
}

.page-disclaimer .breadcrumb a:hover,
.page-disclaimer .breadcrumb a:focus-visible {
  color: var(--cyan);
  border-bottom-color: var(--cyan);
}

/* 首屏 */
.usage-hero {
  max-width: 880px;
  padding-block-end: clamp(28px, 4vw, 44px);
}

.usage-kicker {
  margin: 0 0 14px;
  font-family: var(--font-num);
  font-size: 13px;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: var(--cyan);
}

.usage-hero h1 {
  margin: 0 0 20px;
  font-family: var(--font-head);
  font-size: clamp(30px, 5vw, 56px);
  font-weight: 700;
  line-height: 1.14;
  letter-spacing: 0.01em;
  color: var(--ink);
}

.usage-lead {
  margin: 0;
  max-width: 760px;
  font-size: 17px;
  line-height: 1.8;
  color: var(--ud-body-text);
}

/* 通栏氛围图 */
.usage-banner {
  position: relative;
  margin: 0 0 clamp(40px, 6vw, 72px);
  border: 1px solid var(--line);
  border-radius: var(--r-l);
  overflow: hidden;
  background: var(--panel);
}

.usage-banner img {
  display: block;
  width: 100%;
  height: auto;
  aspect-ratio: 1200 / 420;
  object-fit: cover;
}

.usage-banner figcaption {
  position: absolute;
  left: clamp(16px, 3vw, 28px);
  bottom: clamp(14px, 2.4vw, 22px);
  margin: 0;
  padding: 6px 14px;
  border-radius: var(--r-pill);
  background: rgba(5, 7, 15, 0.72);
  font-size: 13px;
  letter-spacing: 0.04em;
  color: var(--muted);
  backdrop-filter: blur(6px);
}

/* 主体分栏 */
.usage-layout {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: clamp(28px, 4vw, 48px);
  align-items: start;
}

/* 摘录卡 */
.usage-aside {
  order: -1;
}

.usage-aside-card {
  padding: 22px 22px 24px;
  border: 1px solid var(--line);
  border-left: 3px solid var(--cyan);
  border-radius: var(--r-m);
  background:
    linear-gradient(180deg, rgba(46, 230, 222, 0.07), rgba(122, 75, 255, 0.05)),
    var(--raise);
}

.usage-aside-label {
  margin: 0 0 8px;
  font-family: var(--font-num);
  font-size: 12px;
  letter-spacing: 0.2em;
  text-transform: uppercase;
  color: var(--cyan);
}

.usage-aside-card h2 {
  margin: 0 0 16px;
  font-family: var(--font-head);
  font-size: 19px;
  font-weight: 600;
  line-height: 1.35;
  color: var(--ink);
}

.usage-aside-list {
  margin: 0 0 20px;
  padding: 0;
  list-style: none;
  display: grid;
  gap: 14px;
}

.usage-aside-list li {
  display: grid;
  grid-template-columns: 34px minmax(0, 1fr);
  gap: 10px;
  font-size: 14px;
  line-height: 1.7;
  color: var(--ud-body-text);
}

.aside-idx {
  font-family: var(--font-num);
  font-size: 13px;
  line-height: 1.7;
  letter-spacing: 0.08em;
  color: var(--gold);
}

.usage-aside-card .btn-copy {
  width: 100%;
  justify-content: center;
}

/* 正文小节 */
.usage-body {
  min-width: 0;
}

.usage-section {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 10px;
  padding-block: clamp(26px, 3.6vw, 40px);
  border-top: 1px solid var(--line);
}

.usage-section:first-child {
  border-top: 0;
  padding-block-start: 0;
}

.usage-num {
  margin: 0;
  font-family: var(--font-num);
  font-size: 13px;
  letter-spacing: 0.28em;
  color: var(--cyan);
}

.usage-sec-body h2 {
  margin: 0 0 16px;
  font-family: var(--font-head);
  font-size: clamp(21px, 2.6vw, 30px);
  font-weight: 700;
  line-height: 1.28;
  color: var(--ink);
}

.usage-sec-body p {
  margin: 0 0 1.5em;
  font-size: 16.5px;
  line-height: 1.78;
  color: var(--ud-body-text);
}

.usage-sec-body p:last-child {
  margin-bottom: 0;
}

.usage-sec-body a {
  color: var(--cyan);
  text-decoration: none;
  border-bottom: 1px solid rgba(46, 230, 222, 0.4);
  transition: border-color 180ms var(--ease), color 180ms var(--ease);
}

.usage-sec-body a:hover,
.usage-sec-body a:focus-visible {
  color: var(--ink);
  border-bottom-color: var(--ink);
}

/* 数据卡组 */
.usage-stats {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(150px, 1fr));
  gap: 14px;
  margin: 4px 0 1.6em;
}

/* 引用要素表 */
.usage-cite {
  margin: 0 0 1.6em;
  padding: 0;
  list-style: none;
  border: 1px dashed var(--line);
  border-radius: var(--r-m);
  background: linear-gradient(135deg, rgba(46, 230, 222, 0.07), rgba(122, 75, 255, 0.06));
  overflow: hidden;
}

.usage-cite li {
  display: grid;
  grid-template-columns: 96px minmax(0, 1fr);
  gap: 14px;
  align-items: baseline;
  padding: 14px 18px;
  border-top: 1px solid var(--line);
  font-size: 15px;
  line-height: 1.6;
}

.usage-cite li:first-child {
  border-top: 0;
}

.cite-key {
  font-family: var(--font-num);
  font-size: 13px;
  letter-spacing: 0.06em;
  color: var(--gold);
}

.cite-val {
  color: var(--ink);
}

/* 修订记录 */
.usage-log {
  margin: 0 0 1.6em;
  padding: 0;
  list-style: none;
}

.usage-log li {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 6px;
  padding: 14px 0;
  border-bottom: 1px solid var(--line);
}

.usage-log li:first-child {
  border-top: 1px solid var(--line);
}

.log-when {
  font-family: var(--font-num);
  font-size: 13px;
  letter-spacing: 0.1em;
  color: var(--magenta);
}

.log-what {
  font-size: 15.5px;
  line-height: 1.7;
  color: var(--ud-body-text);
}

/* 底部引导条 */
.usage-next {
  margin-block-start: clamp(8px, 1.5vw, 20px);
  padding: clamp(24px, 3.4vw, 38px);
  border: 1px solid var(--line);
  border-radius: var(--r-l);
  background:
    linear-gradient(120deg, rgba(46, 230, 222, 0.10), rgba(255, 62, 157, 0.08) 55%, rgba(122, 75, 255, 0.10)),
    var(--panel);
  display: grid;
  gap: 24px;
}

.usage-next h2 {
  margin: 0 0 12px;
  font-family: var(--font-head);
  font-size: clamp(21px, 2.6vw, 30px);
  font-weight: 700;
  line-height: 1.28;
  color: var(--ink);
}

.usage-next p {
  margin: 0 0 12px;
  max-width: 720px;
  font-size: 16.5px;
  line-height: 1.78;
  color: var(--ud-body-text);
}

.usage-next-contact {
  margin: 0;
  font-family: var(--font-num);
  font-size: 14px;
  letter-spacing: 0.02em;
  color: var(--cyan);
}

.usage-next-links {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
}

/* 返回顶部 */
.page-disclaimer .to-top {
  position: fixed;
  right: clamp(14px, 3vw, 28px);
  bottom: clamp(72px, 10vw, 96px);
  z-index: 30;
  display: grid;
  place-items: center;
  width: 44px;
  height: 44px;
  border: 1px solid var(--line);
  border-radius: 50%;
  background: rgba(22, 32, 60, 0.86);
  color: var(--cyan);
  font-size: 17px;
  line-height: 1;
  text-decoration: none;
  backdrop-filter: blur(8px);
  transition: border-color 200ms var(--ease), transform 200ms var(--ease);
}

.page-disclaimer .to-top:hover,
.page-disclaimer .to-top:focus-visible {
  border-color: var(--cyan);
  transform: translateY(-2px);
}

/* 响应式 */
@media (min-width: 720px) {
  .usage-section {
    grid-template-columns: 58px minmax(0, 1fr);
    gap: 20px;
  }

  .usage-num {
    padding-top: 6px;
  }

  .usage-log li {
    grid-template-columns: 132px minmax(0, 1fr);
    gap: 18px;
    align-items: baseline;
  }

  .usage-next {
    grid-template-columns: minmax(0, 1fr) auto;
    align-items: center;
  }

  .usage-next-text p:last-child {
    margin-bottom: 0;
  }
}

@media (min-width: 960px) {
  .usage-layout {
    grid-template-columns: minmax(0, 1fr) minmax(288px, 340px);
    gap: clamp(40px, 4vw, 64px);
  }

  .usage-aside {
    order: 0;
  }

  .usage-aside-card {
    position: sticky;
    top: 104px;
  }

  .usage-sec-body p {
    font-size: 17px;
  }
}

@media (min-width: 1200px) {
  .usage-hero {
    max-width: 920px;
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-disclaimer .breadcrumb a,
  .page-disclaimer .to-top,
  .usage-sec-body a {
    transition: none;
  }

  .page-disclaimer .to-top:hover,
  .page-disclaimer .to-top:focus-visible {
    transform: none;
  }
}