.page-disclaimer {
  --u-rail: 200px;
  --u-numcol: 64px;
  --u-measure: 44rem;
  --u-ease: cubic-bezier(.2, .7, .2, 1);
  background: var(--bg);
  color: var(--snow);
  font-family: var(--font-sans);
  -webkit-font-smoothing: antialiased;
}

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

/* ---------- 首屏 ---------- */

.page-disclaimer .usage-hero {
  position: relative;
  border-bottom: 1px solid var(--line);
  overflow: hidden;
}

.page-disclaimer .usage-hero::before {
  content: "";
  position: absolute;
  inset: 0;
  background-image:
    linear-gradient(to right, var(--line) 1px, transparent 1px),
    linear-gradient(to bottom, var(--line) 1px, transparent 1px);
  background-size: 88px 88px;
  opacity: .45;
  pointer-events: none;
}

.page-disclaimer .usage-hero__inner {
  position: relative;
  z-index: 1;
  padding-block: clamp(30px, 5.5vw, 66px) clamp(28px, 4.5vw, 52px);
}

.page-disclaimer .usage-hero__title {
  margin: 18px 0 0;
  max-width: 18ch;
  font-weight: 200;
  font-size: clamp(30px, 6.2vw, 70px);
  line-height: 1.06;
  letter-spacing: -.02em;
  color: var(--snow);
}

.page-disclaimer .usage-hero__lede {
  margin-top: 22px;
  max-width: 46rem;
  color: var(--snow);
  opacity: .82;
}

.page-disclaimer .usage-hero__facts {
  display: flex;
  flex-wrap: wrap;
  gap: 14px 34px;
  margin-top: clamp(26px, 3.6vw, 40px);
  padding-top: 20px;
  border-top: 1px solid var(--line);
}

.page-disclaimer .usage-hero__fact {
  display: inline-flex;
  align-items: baseline;
  gap: 8px;
  font-size: 13px;
  letter-spacing: .05em;
  color: var(--index);
}

.page-disclaimer .usage-hero__fact b {
  font-family: var(--font-mono);
  font-size: 22px;
  font-weight: 700;
  letter-spacing: 0;
  color: var(--orange);
  font-variant-numeric: tabular-nums;
}

.page-disclaimer .usage-hero__media {
  position: relative;
  margin: 0;
  border-top: 1px solid var(--line);
  background: var(--panel);
}

.page-disclaimer .usage-hero__media::after {
  content: "";
  position: absolute;
  left: 0;
  right: 0;
  bottom: 0;
  height: 3px;
  background: linear-gradient(90deg, var(--orange) 0 22%, var(--cyan) 22% 46%, transparent 46% 100%);
}

.page-disclaimer .usage-hero__media img {
  display: block;
  width: 100%;
  height: auto;
  aspect-ratio: 16 / 5;
  object-fit: cover;
  filter: saturate(.85) contrast(1.06);
}

/* ---------- 主布局 ---------- */

.page-disclaimer .usage-layout {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: clamp(32px, 5vw, 56px);
  padding-block: clamp(38px, 6vw, 78px) clamp(56px, 8vw, 110px);
}

/* ---------- 索引轨道 ---------- */

.page-disclaimer .usage-rail__kicker {
  margin: 0;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: .18em;
  color: var(--index);
}

.page-disclaimer .usage-rail__list {
  display: flex;
  gap: 8px;
  margin: 14px 0 0;
  padding: 0 0 10px;
  list-style: none;
  overflow-x: auto;
  scrollbar-width: thin;
  -webkit-overflow-scrolling: touch;
}

.page-disclaimer .usage-rail__link {
  position: relative;
  display: block;
  padding: 10px 14px 10px 16px;
  border: 1px solid var(--line);
  background: var(--panel);
  color: var(--index);
  font-size: 14px;
  line-height: 1.4;
  text-decoration: none;
  white-space: nowrap;
  transition: color .24s var(--u-ease), border-color .24s var(--u-ease);
}

.page-disclaimer .usage-rail__link::before {
  content: "";
  position: absolute;
  left: 0;
  top: 0;
  bottom: 0;
  width: 2px;
  background: var(--orange);
  transform: scaleY(0);
  transform-origin: top;
  transition: transform .24s var(--u-ease);
}

.page-disclaimer .usage-rail__link:hover,
.page-disclaimer .usage-rail__link:focus-visible {
  color: var(--snow);
  border-color: var(--cyan);
}

.page-disclaimer .usage-rail__link[aria-current],
.page-disclaimer .usage-rail__link.is-active {
  color: var(--snow);
  border-color: var(--line);
}

.page-disclaimer .usage-rail__link[aria-current]::before,
.page-disclaimer .usage-rail__link.is-active::before {
  transform: scaleY(1);
}

.page-disclaimer .usage-rail__note {
  margin: 16px 0 0;
  font-size: 13px;
  line-height: 1.7;
  color: var(--index);
}

/* ---------- 条款正文 ---------- */

.page-disclaimer .usage-body {
  display: flex;
  flex-direction: column;
  gap: clamp(46px, 6.5vw, 84px);
  min-width: 0;
  max-width: var(--u-measure);
}

.page-disclaimer .usage-part {
  scroll-margin-top: 84px;
}

.page-disclaimer .usage-part__head {
  display: grid;
  gap: 14px;
  padding-bottom: 18px;
  border-bottom: 1px solid var(--line);
}

.page-disclaimer .usage-part__title {
  margin: 0;
  font-weight: 200;
  font-size: clamp(25px, 3.6vw, 40px);
  line-height: 1.14;
  letter-spacing: -.01em;
  color: var(--snow);
}

.page-disclaimer .usage-part__intro {
  margin: 0;
  font-size: 15px;
  line-height: 1.75;
  color: var(--index);
}

.page-disclaimer .usage-list {
  margin: 0;
  padding: 0;
  list-style: none;
}

.page-disclaimer .usage-item {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 8px;
  padding: clamp(22px, 3.2vw, 34px) 0;
  border-bottom: 1px solid var(--line);
  transition: opacity .24s var(--u-ease), transform .24s var(--u-ease);
}

.page-disclaimer .usage-item__num {
  font-family: var(--font-mono);
  font-size: 22px;
  font-weight: 700;
  line-height: 1;
  letter-spacing: .02em;
  color: var(--orange);
  font-variant-numeric: tabular-nums;
}

.page-disclaimer .usage-item__title {
  margin: 0 0 8px;
  font-size: 17px;
  font-weight: 600;
  line-height: 1.5;
  color: var(--snow);
}

.page-disclaimer .usage-item__text {
  margin: 0;
  font-size: 16px;
  line-height: 1.78;
  color: rgba(233, 239, 244, .78);
  overflow-wrap: break-word;
}

.page-disclaimer .usage-item--key .usage-item__num {
  color: var(--lime);
}

.page-disclaimer .usage-mark {
  padding-bottom: 1px;
  background: linear-gradient(transparent 62%, rgba(182, 255, 60, .3) 62%);
  color: var(--snow);
}

/* ---------- 引用示例 ---------- */

.page-disclaimer .usage-sample {
  margin-top: clamp(26px, 3.4vw, 36px);
  border: 1px solid var(--line);
  background: var(--panel);
}

.page-disclaimer .usage-sample__head {
  margin: 0;
  padding: 12px 18px;
  border-bottom: 1px solid var(--line);
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: .18em;
  color: var(--index);
}

.page-disclaimer .usage-sample__body {
  margin: 0;
  padding: 20px 18px;
  overflow-x: auto;
  font-family: var(--font-mono);
  font-size: 13px;
  line-height: 2;
  color: var(--cyan);
  white-space: pre;
  -webkit-overflow-scrolling: touch;
}

/* ---------- 折叠延伸 ---------- */

.page-disclaimer .usage-details {
  margin-top: clamp(24px, 3.2vw, 34px);
  border: 1px solid var(--line);
  background: var(--panel);
}

.page-disclaimer .usage-details summary {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  padding: 16px 18px;
  cursor: pointer;
  list-style: none;
  font-size: 15px;
  font-weight: 600;
  line-height: 1.5;
  color: var(--snow);
  transition: color .24s var(--u-ease);
}

.page-disclaimer .usage-details summary::-webkit-details-marker {
  display: none;
}

.page-disclaimer .usage-details summary:hover {
  color: var(--cyan);
}

.page-disclaimer .usage-details summary::after {
  content: "＋";
  flex: none;
  font-family: var(--font-mono);
  font-size: 15px;
  color: var(--orange);
}

.page-disclaimer .usage-details[open] summary::after {
  content: "－";
}

.page-disclaimer .usage-details__body {
  padding: 0 18px 20px;
  border-top: 1px solid var(--line);
}

.page-disclaimer .usage-details__body p {
  margin: 16px 0 0;
  font-size: 15px;
  line-height: 1.8;
  color: rgba(233, 239, 244, .76);
}

/* ---------- 相关入口与回顶 ---------- */

.page-disclaimer .usage-next {
  display: flex;
  flex-wrap: wrap;
  gap: 10px 12px;
  padding-top: clamp(28px, 4vw, 44px);
  border-top: 1px solid var(--line);
}

.page-disclaimer .usage-next a {
  padding: 9px 16px;
  border: 1px solid var(--line);
  color: var(--snow);
  font-size: 13px;
  letter-spacing: .04em;
  text-decoration: none;
  transition: border-color .24s var(--u-ease), color .24s var(--u-ease);
}

.page-disclaimer .usage-next a:hover,
.page-disclaimer .usage-next a:focus-visible {
  border-color: var(--orange);
  color: var(--orange);
}

.page-disclaimer .usage-foot {
  margin: 0;
}

.page-disclaimer .usage-totop {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  padding: 12px 20px;
  border: 1px solid var(--line);
  background: transparent;
  color: var(--snow);
  font-size: 13px;
  letter-spacing: .06em;
  text-decoration: none;
  transition: border-color .24s var(--u-ease), color .24s var(--u-ease);
}

.page-disclaimer .usage-totop:hover,
.page-disclaimer .usage-totop:focus-visible {
  border-color: var(--orange);
  color: var(--orange);
}

.page-disclaimer .usage-totop__arrow {
  font-family: var(--font-mono);
  color: var(--orange);
}

/* ---------- 桌面 ---------- */

@media (min-width: 760px) {
  .page-disclaimer .usage-item {
    grid-template-columns: var(--u-numcol) minmax(0, 1fr);
    gap: clamp(20px, 2.6vw, 36px);
    align-items: start;
  }

  .page-disclaimer .usage-item__num {
    font-size: 28px;
    padding-top: 2px;
  }
}

@media (min-width: 980px) {
  .page-disclaimer .usage-layout {
    grid-template-columns: var(--u-rail) minmax(0, 1fr);
    gap: clamp(48px, 5.5vw, 88px);
    justify-content: start;
  }

  .page-disclaimer .usage-rail {
    position: sticky;
    top: 96px;
    align-self: start;
    padding-left: 20px;
    border-left: 1px solid var(--line);
  }

  .page-disclaimer .usage-rail__list {
    flex-direction: column;
    gap: 2px;
    padding-bottom: 0;
    overflow: visible;
  }

  .page-disclaimer .usage-rail__link {
    border-color: transparent;
    border-bottom-color: var(--line);
    background: transparent;
    padding: 11px 12px 11px 16px;
    white-space: normal;
  }
}

@media (min-width: 1200px) {
  .page-disclaimer .usage-hero__inner {
    padding-block: 78px 58px;
  }

  .page-disclaimer .usage-item__num {
    font-size: 32px;
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-disclaimer .usage-rail__link,
  .page-disclaimer .usage-rail__link::before,
  .page-disclaimer .usage-item,
  .page-disclaimer .usage-next a,
  .page-disclaimer .usage-totop,
  .page-disclaimer .usage-details summary {
    transition: none;
  }
}