/* ===== 使用指引页 /usage/ ===== */

.page-disclaimer {
  background: var(--cream);
  color: var(--text);
  font-family: var(--font-body);
  font-size: 17px;
  line-height: 1.75;
}

/* ---------- 首屏 ---------- */

.page-disclaimer .usage-hero {
  position: relative;
  padding: calc(var(--header-h) + 40px) 0 52px;
  background:
    radial-gradient(120% 130% at 88% -10%, rgba(46, 230, 176, 0.20), transparent 58%),
    radial-gradient(95% 95% at 6% 112%, rgba(31, 122, 77, 0.44), transparent 62%),
    var(--ink);
  color: var(--cream);
  border-bottom-left-radius: var(--radius-lg);
  border-bottom-right-radius: var(--radius-lg);
}

.page-disclaimer .usage-hero .breadcrumb {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 6px;
  font-size: 14px;
  color: rgba(244, 241, 232, 0.66);
}

.page-disclaimer .usage-hero .breadcrumb a {
  color: rgba(244, 241, 232, 0.88);
  text-decoration: none;
  border-bottom: 1px solid rgba(244, 241, 232, 0.32);
  transition: color 160ms ease-out, border-color 160ms ease-out;
}

.page-disclaimer .usage-hero .breadcrumb a:hover {
  color: var(--cyan);
  border-color: var(--cyan);
}

.page-disclaimer .usage-hero .breadcrumb-sep {
  color: rgba(244, 241, 232, 0.4);
}

.page-disclaimer .usage-hero .eyebrow {
  margin: 24px 0 0;
  font-family: var(--font-mono);
  font-size: 12.5px;
  letter-spacing: 0.16em;
  color: var(--cyan);
}

.page-disclaimer .usage-hero h1 {
  margin: 14px 0 0;
  max-width: 16em;
  font-family: var(--font-display);
  font-weight: 800;
  font-size: clamp(30px, 7vw, 54px);
  line-height: 1.14;
  letter-spacing: -0.02em;
  color: var(--white);
}

.page-disclaimer .usage-lede {
  margin: 20px 0 0;
  max-width: 40em;
  font-size: 16.5px;
  line-height: 1.8;
  color: rgba(244, 241, 232, 0.84);
}

.page-disclaimer .usage-chips {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  margin: 28px 0 0;
  padding: 0;
  list-style: none;
}

/* ---------- 主体骨架 ---------- */

.page-disclaimer .usage-shell {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 32px;
  padding-top: 40px;
  padding-bottom: 8px;
}

/* ---------- 目录 ---------- */

.page-disclaimer .usage-toc {
  padding: 18px 16px 20px;
  background: var(--white);
  border: 1px solid var(--line);
  border-radius: var(--radius-md);
}

.page-disclaimer .usage-toc-title {
  margin: 0 0 12px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.16em;
  color: var(--slate);
}

.page-disclaimer .usage-toc ol {
  display: grid;
  gap: 4px;
  margin: 0;
  padding: 0;
  list-style: none;
}

.page-disclaimer .usage-toc a {
  display: flex;
  align-items: baseline;
  gap: 10px;
  padding: 9px 12px;
  border-radius: 999px;
  font-size: 15px;
  color: var(--ink);
  text-decoration: none;
  transition: background-color 120ms ease-out, color 120ms ease-out;
}

.page-disclaimer .usage-toc a:hover {
  background: rgba(31, 122, 77, 0.08);
}

.page-disclaimer .usage-toc a .mono {
  font-family: var(--font-mono);
  font-size: 12.5px;
  color: var(--clay);
}

.page-disclaimer .usage-toc a.is-current {
  background: rgba(46, 230, 176, 0.20);
  color: var(--grass-deep);
  font-weight: 700;
}

.page-disclaimer .usage-toc a.is-current .mono {
  color: var(--grass-deep);
}

/* ---------- 章节 ---------- */

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

.page-disclaimer .usage-section {
  padding: 34px 0 8px;
  border-top: 1px solid var(--line);
}

.page-disclaimer .usage-main > .usage-section:first-child {
  padding-top: 0;
  border-top: 0;
}

.page-disclaimer .usage-section-head {
  display: flex;
  align-items: baseline;
  gap: 14px;
}

.page-disclaimer .usage-index {
  margin: 0;
  font-family: var(--font-mono);
  font-size: 15px;
  letter-spacing: 0.1em;
  color: var(--clay);
}

.page-disclaimer .usage-section h2 {
  margin: 0;
  font-family: var(--font-display);
  font-weight: 800;
  font-size: clamp(23px, 5vw, 32px);
  line-height: 1.22;
  letter-spacing: -0.01em;
  color: var(--ink);
}

.page-disclaimer .usage-section h2::after {
  content: "";
  display: block;
  width: 46px;
  height: 2px;
  margin-top: 12px;
  border-radius: 2px;
  background: var(--clay);
}

.page-disclaimer .usage-intro {
  max-width: 42em;
  margin: 20px 0 0;
  color: var(--text-muted);
}

/* ---------- 规范条目 ---------- */

.page-disclaimer .spec-list {
  display: grid;
  gap: 12px;
  margin-top: 24px;
}

.page-disclaimer .spec {
  display: grid;
  grid-template-columns: 34px minmax(0, 1fr);
  gap: 14px;
  max-width: 780px;
  padding: 18px 18px 18px 16px;
  background: var(--white);
  border: 1px solid var(--line);
  border-radius: var(--radius-md);
}

.page-disclaimer .spec-num {
  display: grid;
  place-items: center;
  width: 34px;
  height: 34px;
  border-radius: 50%;
  background: rgba(31, 122, 77, 0.10);
  border: 1px solid rgba(31, 122, 77, 0.26);
  font-family: var(--font-mono);
  font-size: 13px;
  font-weight: 700;
  color: var(--grass-deep);
}

.page-disclaimer .spec-body h3 {
  margin: 0;
  font-family: var(--font-display);
  font-weight: 700;
  font-size: 17.5px;
  line-height: 1.5;
  color: var(--ink);
}

.page-disclaimer .spec-body p {
  margin: 8px 0 0;
  font-size: 16px;
  color: var(--text-muted);
}

.page-disclaimer .spec-body strong {
  color: var(--grass-deep);
  font-weight: 700;
}

.page-disclaimer .spec-body a {
  color: var(--grass);
  text-decoration: none;
  border-bottom: 1px solid rgba(31, 122, 77, 0.4);
}

.page-disclaimer .spec-body a:hover {
  color: var(--grass-deep);
  border-color: var(--grass-deep);
}

/* ---------- 常见误用（可展开） ---------- */

.page-disclaimer .misuse {
  max-width: 780px;
  margin-top: 18px;
  border: 1px dashed rgba(199, 99, 58, 0.52);
  border-radius: var(--radius-md);
  background: rgba(199, 99, 58, 0.06);
}

.page-disclaimer .misuse summary {
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 16px 18px;
  cursor: pointer;
  list-style: none;
  font-family: var(--font-display);
  font-weight: 700;
  font-size: 16px;
  color: var(--clay);
}

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

.page-disclaimer .misuse summary::after {
  content: "+";
  margin-left: auto;
  font-family: var(--font-mono);
  font-size: 20px;
  line-height: 1;
  transition: transform 200ms ease-out;
}

.page-disclaimer .misuse[open] summary::after {
  content: "−";
}

.page-disclaimer .misuse-body {
  padding: 0 18px 18px;
}

.page-disclaimer .misuse-body ul {
  display: grid;
  gap: 10px;
  margin: 0;
  padding-left: 18px;
  font-size: 15.5px;
  color: var(--text-muted);
}

.page-disclaimer .misuse-body strong {
  color: var(--ink);
}

/* ---------- 中段图版 ---------- */

.page-disclaimer .usage-break {
  margin: 30px 0 34px;
}

.page-disclaimer .usage-break img {
  display: block;
  width: 100%;
  height: auto;
  object-fit: cover;
}

.page-disclaimer .usage-break figcaption {
  margin-top: 10px;
  font-family: var(--font-serif);
  font-size: 14.5px;
  color: var(--slate);
}

/* ---------- 深色收尾 ---------- */

.page-disclaimer .usage-outro {
  margin-top: 36px;
  padding: 52px 0 58px;
  background:
    radial-gradient(110% 120% at 92% 0%, rgba(46, 230, 176, 0.14), transparent 58%),
    var(--ink);
  color: var(--cream);
  border-top-left-radius: var(--radius-lg);
  border-top-right-radius: var(--radius-lg);
}

.page-disclaimer .usage-outro-inner {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 28px;
}

.page-disclaimer .usage-outro .usage-index {
  color: var(--cyan);
}

.page-disclaimer .usage-outro h2 {
  margin: 10px 0 0;
  font-family: var(--font-display);
  font-weight: 800;
  font-size: clamp(23px, 5vw, 32px);
  line-height: 1.22;
  letter-spacing: -0.01em;
  color: var(--white);
}

.page-disclaimer .usage-outro-lede {
  max-width: 40em;
  margin: 16px 0 0;
  color: rgba(244, 241, 232, 0.82);
}

.page-disclaimer .usage-outro-list {
  display: grid;
  gap: 14px;
  margin: 26px 0 0;
  padding: 0;
  list-style: none;
}

.page-disclaimer .usage-outro-list li {
  padding-left: 16px;
  border-left: 2px solid rgba(46, 230, 176, 0.5);
  font-size: 15.5px;
  color: rgba(244, 241, 232, 0.82);
}

.page-disclaimer .usage-outro-list strong {
  color: var(--flare);
  font-weight: 700;
}

.page-disclaimer .usage-outro-list a {
  color: var(--cyan);
  text-decoration: none;
  border-bottom: 1px solid rgba(46, 230, 176, 0.45);
}

.page-disclaimer .usage-outro-list a:hover {
  color: var(--white);
  border-color: var(--white);
}

.page-disclaimer .usage-outro-cta {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
}

.page-disclaimer .usage-outro .btn--ghost {
  border-color: rgba(244, 241, 232, 0.5);
  color: var(--cream);
}

.page-disclaimer .usage-outro .btn--ghost:hover {
  border-color: var(--cyan);
  color: var(--cyan);
}

/* ---------- 响应式 ---------- */

@media (min-width: 640px) {
  .page-disclaimer .spec {
    grid-template-columns: 40px minmax(0, 1fr);
    gap: 16px;
    padding: 20px 22px 20px 18px;
  }

  .page-disclaimer .spec-num {
    width: 40px;
    height: 40px;
    font-size: 14px;
  }

  .page-disclaimer .spec-body h3 {
    font-size: 18.5px;
  }

  .page-disclaimer .usage-lede {
    font-size: 17.5px;
  }
}

@media (min-width: 900px) {
  .page-disclaimer .usage-shell {
    grid-template-columns: 258px minmax(0, 1fr);
    gap: 56px;
    padding-top: 56px;
  }

  .page-disclaimer .usage-toc {
    position: sticky;
    top: calc(var(--header-h-min) + 24px);
    align-self: start;
  }

  .page-disclaimer .usage-section {
    padding: 44px 0 10px;
  }

  .page-disclaimer .usage-main > .usage-section:first-child {
    padding-top: 4px;
  }

  .page-disclaimer .usage-break {
    margin: 40px 0 44px;
  }

  .page-disclaimer .usage-outro-inner {
    grid-template-columns: minmax(0, 1fr) 250px;
    align-items: start;
    gap: 56px;
  }

  .page-disclaimer .usage-outro-cta {
    flex-direction: column;
    align-items: stretch;
  }

  .page-disclaimer .usage-outro-cta .btn {
    text-align: center;
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-disclaimer .usage-toc a,
  .page-disclaimer .usage-hero .breadcrumb a,
  .page-disclaimer .misuse summary::after {
    transition: none;
  }
}