/* ===== 使用指引 /usage/ ===== */
.page-disclaimer {
  --u-sec-pad: 46px;
  --u-gap: 18px;
  display: block;
  background: var(--ink);
  color: var(--text);
}

/* ---------- 首屏 ---------- */
.page-disclaimer .usage-top {
  position: relative;
  overflow: hidden;
  padding: 34px 0 40px;
  background: linear-gradient(158deg, var(--ink-2) 0%, var(--ink) 64%);
  border-bottom: 1px solid var(--line);
}

.page-disclaimer .usage-top::before {
  content: "";
  position: absolute;
  inset: 0;
  background-image:
    linear-gradient(90deg, var(--line) 1px, transparent 1px),
    linear-gradient(0deg, var(--line) 1px, transparent 1px);
  background-size: 24px 24px;
  opacity: .3;
  pointer-events: none;
  animation: usage-grid-drift 12s linear infinite;
}

@keyframes usage-grid-drift {
  from { background-position: 0 0, 0 0; }
  to { background-position: 24px 24px, 24px 24px; }
}

.page-disclaimer .usage-top .container {
  position: relative;
  z-index: 1;
}

.page-disclaimer .eyebrow {
  margin: 16px 0 0;
  color: var(--cyan);
  font-family: var(--mono);
  font-size: 12px;
  letter-spacing: .08em;
}

.page-disclaimer .usage-title {
  margin: 10px 0 16px;
  max-width: 19ch;
  font-family: var(--sans);
  font-weight: 800;
  font-size: clamp(28px, 6.6vw, 54px);
  line-height: 1.1;
  letter-spacing: -.02em;
  color: var(--paper);
}

.page-disclaimer .usage-lede {
  margin: 0;
  max-width: 62ch;
  font-size: 16px;
  line-height: 1.8;
  color: var(--text);
}

/* ---------- 章节锚点 ---------- */
.page-disclaimer .usage-anchors {
  list-style: none;
  margin: 28px 0 0;
  padding: 0;
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 10px;
}

.page-disclaimer .usage-anchor {
  display: flex;
  align-items: baseline;
  gap: 10px;
  padding: 12px 14px;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: rgba(18, 49, 37, .55);
  color: var(--text);
  text-decoration: none;
  font-size: 14px;
  line-height: 1.5;
  transition: transform .12s var(--ease), border-color .12s var(--ease), color .12s var(--ease);
}

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

.page-disclaimer .usage-anchor-num {
  flex: none;
  font-family: var(--mono);
  font-weight: 700;
  font-size: 12px;
  letter-spacing: .06em;
  color: var(--cyan);
}

/* ---------- 章节容器 ---------- */
.page-disclaimer .usage-sec {
  padding: var(--u-sec-pad) 0;
  border-bottom: 1px solid var(--line);
}

.page-disclaimer .usage-sec--alt {
  background: var(--ink-2);
}

.page-disclaimer .usage-sec-head {
  display: flex;
  align-items: center;
  flex-wrap: wrap;
  gap: 14px;
  margin-bottom: 20px;
}

.page-disclaimer .usage-num {
  flex: none;
  padding: 8px 9px;
  border: 1px solid var(--cyan);
  border-radius: 2px;
  background: rgba(56, 225, 196, .08);
  font-family: var(--mono);
  font-weight: 700;
  font-size: 18px;
  line-height: 1;
  letter-spacing: -.02em;
  color: var(--cyan);
}

.page-disclaimer .usage-sec-head h2 {
  margin: 0;
  font-family: var(--sans);
  font-weight: 800;
  font-size: clamp(21px, 3.6vw, 30px);
  line-height: 1.22;
  letter-spacing: -.02em;
  color: var(--paper);
}

.page-disclaimer .usage-body {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 22px;
}

.page-disclaimer .usage-text p {
  margin: 0 0 .9em;
  max-width: 66ch;
  font-size: 16px;
  line-height: 1.78;
  color: var(--text);
}

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

.page-disclaimer .usage-text a,
.page-disclaimer .usage-warn a,
.page-disclaimer .usage-next-foot a {
  color: var(--cyan);
  text-decoration: underline;
  text-underline-offset: 3px;
}

/* ---------- 规范条目 ---------- */
.page-disclaimer .usage-list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 12px;
}

.page-disclaimer .usage-item {
  display: flex;
  gap: 14px;
  padding: 16px 18px;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: var(--panel-soft);
}

.page-disclaimer .usage-item::before {
  content: "";
  flex: none;
  width: 9px;
  height: 9px;
  margin-top: 7px;
  border-radius: 1px;
  background: var(--cyan);
}

.page-disclaimer .usage-item-body {
  min-width: 0;
}

.page-disclaimer .usage-item-key {
  display: block;
  margin-bottom: 6px;
  font-family: var(--mono);
  font-size: 12px;
  letter-spacing: .08em;
  color: var(--cyan);
}

.page-disclaimer .usage-item p {
  margin: 0;
  max-width: 62ch;
  font-size: 15px;
  line-height: 1.78;
  color: var(--text);
}

/* ---------- 折叠分组 ---------- */
.page-disclaimer .usage-folds {
  display: grid;
  gap: 10px;
}

.page-disclaimer .usage-fold {
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: var(--panel-soft);
}

.page-disclaimer .usage-fold > summary {
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 15px 16px;
  cursor: pointer;
  list-style: none;
  font-family: var(--sans);
  font-weight: 700;
  font-size: 15px;
  line-height: 1.5;
  color: var(--paper);
  transition: color .12s var(--ease);
}

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

.page-disclaimer .usage-fold > summary::before {
  content: "+";
  flex: none;
  width: 12px;
  text-align: center;
  font-family: var(--mono);
  font-weight: 700;
  font-size: 16px;
  line-height: 1;
  color: var(--cyan);
}

.page-disclaimer .usage-fold[open] > summary::before {
  content: "–";
}

.page-disclaimer .usage-fold > summary:hover,
.page-disclaimer .usage-fold > summary:focus-visible {
  color: var(--cyan);
}

.page-disclaimer .usage-fold > summary:focus-visible {
  outline: 2px solid var(--cyan);
  outline-offset: -2px;
}

.page-disclaimer .usage-fold-body {
  padding: 0 16px 16px 40px;
  max-width: 72ch;
  font-size: 15px;
  line-height: 1.78;
  color: var(--text);
}

/* ---------- 易错点提示块 ---------- */
.page-disclaimer .usage-note {
  padding: 18px 18px 6px;
  border: 1px solid rgba(245, 196, 81, .55);
  border-radius: var(--radius);
  background: rgba(245, 196, 81, .05);
}

.page-disclaimer .usage-note-label {
  display: inline-block;
  margin-bottom: 14px;
  padding: 3px 7px;
  border: 1px solid var(--warn);
  border-radius: 2px;
  font-family: var(--mono);
  font-size: 11px;
  letter-spacing: .08em;
  color: var(--warn);
}

.page-disclaimer .usage-warn {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 16px;
}

.page-disclaimer .usage-warn li {
  max-width: 68ch;
  padding-bottom: 16px;
  border-bottom: 1px dashed var(--line);
  font-size: 15px;
  line-height: 1.78;
  color: var(--text);
}

.page-disclaimer .usage-warn li:last-child {
  padding-bottom: 4px;
  border-bottom: 0;
}

.page-disclaimer .usage-warn-key {
  display: block;
  margin-bottom: 5px;
  font-family: var(--mono);
  font-size: 12px;
  letter-spacing: .08em;
  color: var(--warn);
}

/* ---------- 处理流程 ---------- */
.page-disclaimer .usage-flow {
  position: relative;
  list-style: none;
  margin: 24px 0 0;
  padding: 0 0 0 26px;
}

.page-disclaimer .usage-flow::before {
  content: "";
  position: absolute;
  left: 5px;
  top: 6px;
  bottom: 6px;
  width: 1px;
  background: linear-gradient(180deg, var(--cyan) 0%, var(--orange) 100%);
  opacity: .55;
}

.page-disclaimer .usage-flow-step {
  position: relative;
  padding-bottom: 22px;
}

.page-disclaimer .usage-flow-step:last-child {
  padding-bottom: 0;
}

.page-disclaimer .usage-flow-step::before {
  content: "";
  position: absolute;
  left: -26px;
  top: 6px;
  width: 11px;
  height: 11px;
  border-radius: 50%;
  background: var(--cyan);
}

.page-disclaimer .usage-flow-step:last-child::before {
  background: var(--orange);
}

.page-disclaimer .usage-flow-num {
  font-family: var(--mono);
  font-size: 12px;
  letter-spacing: .08em;
  color: var(--cyan);
}

.page-disclaimer .usage-flow-step:last-child .usage-flow-num {
  color: var(--orange);
}

.page-disclaimer .usage-flow-step h3 {
  margin: 5px 0 6px;
  font-family: var(--sans);
  font-weight: 800;
  font-size: 17px;
  letter-spacing: -.01em;
  color: var(--paper);
}

.page-disclaimer .usage-flow-step p {
  margin: 0;
  max-width: 48ch;
  font-size: 15px;
  line-height: 1.78;
  color: var(--text);
}

/* ---------- 配图 ---------- */
.page-disclaimer .usage-figure {
  margin: 28px 0 0;
}

.page-disclaimer .usage-figure img {
  display: block;
  width: 100%;
  max-width: 100%;
  height: auto;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  object-fit: cover;
}

.page-disclaimer .usage-figure .media-cap {
  margin-top: 10px;
  font-family: var(--mono);
  font-size: 12px;
  letter-spacing: .04em;
  color: var(--dim);
}

/* ---------- 结尾导航 ---------- */
.page-disclaimer .usage-next {
  padding: 46px 0 56px;
  background: linear-gradient(180deg, var(--ink-2) 0%, var(--ink) 100%);
}

.page-disclaimer .usage-next h2 {
  margin: 0 0 20px;
  font-family: var(--sans);
  font-weight: 800;
  font-size: clamp(20px, 3.2vw, 26px);
  letter-spacing: -.02em;
  color: var(--paper);
}

.page-disclaimer .usage-next-grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 12px;
}

.page-disclaimer .usage-next-card {
  display: block;
  padding: 18px;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: rgba(18, 49, 37, .5);
  text-decoration: none;
  transition: transform .12s var(--ease), border-color .12s var(--ease);
}

.page-disclaimer .usage-next-card:hover,
.page-disclaimer .usage-next-card:focus-visible {
  transform: translateY(-3px);
  border-color: var(--cyan);
}

.page-disclaimer .usage-next-card strong {
  display: block;
  margin-bottom: 6px;
  font-family: var(--mono);
  font-weight: 700;
  font-size: 14px;
  letter-spacing: .02em;
  color: var(--cyan);
}

.page-disclaimer .usage-next-card span {
  display: block;
  font-size: 14px;
  line-height: 1.7;
  color: var(--text);
}

.page-disclaimer .usage-next-foot {
  margin: 22px 0 0;
  max-width: 62ch;
  font-size: 13px;
  line-height: 1.75;
  color: var(--dim);
}

/* ---------- 右下角反馈浮标 ---------- */
.page-disclaimer .usage-dock {
  position: fixed;
  right: 14px;
  bottom: 14px;
  z-index: 40;
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 10px 15px;
  border: 1px solid var(--line);
  border-radius: 999px;
  background: var(--panel);
  color: var(--paper);
  font-size: 13px;
  font-weight: 700;
  text-decoration: none;
  box-shadow: 0 6px 22px rgba(0, 0, 0, .45);
  transition: border-color .12s var(--ease), transform .12s var(--ease);
}

.page-disclaimer .usage-dock:hover,
.page-disclaimer .usage-dock:focus-visible {
  border-color: var(--orange);
  transform: translateY(-2px);
}

.page-disclaimer .usage-dock-dot {
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background: var(--orange);
  box-shadow: 0 0 0 3px rgba(255, 122, 47, .22);
}

/* ---------- 断点 ---------- */
@media (min-width: 640px) {
  .page-disclaimer .usage-anchors {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

  .page-disclaimer .usage-next-grid {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
}

@media (min-width: 860px) {
  .page-disclaimer {
    --u-sec-pad: 56px;
  }

  .page-disclaimer .usage-top {
    padding: 48px 0 54px;
  }

  .page-disclaimer .usage-dock {
    right: 24px;
    bottom: 24px;
  }
}

@media (min-width: 1024px) {
  .page-disclaimer .usage-anchors {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }

  .page-disclaimer .usage-body {
    grid-template-columns: minmax(0, 5fr) minmax(0, 7fr);
    gap: 38px;
    align-items: start;
  }

  .page-disclaimer .usage-next-grid {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }

  .page-disclaimer .usage-flow {
    margin-top: 30px;
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-disclaimer .usage-top::before {
    animation: none;
  }

  .page-disclaimer .usage-anchor,
  .page-disclaimer .usage-next-card,
  .page-disclaimer .usage-dock {
    transition: none;
  }
}