:root {
  --bg: #f6f8fb;
  --surface: #fff;
  --text: #1a2332;
  --text-muted: #5c6b7f;
  --border: #e2e8f0;
  --accent: #2962ff;
  --accent-soft: rgba(41, 98, 255, 0.1);
  --radius: 12px;
  --shadow: 0 8px 30px rgba(26, 35, 50, 0.08);
  --font-sans: "PingFang SC", "PingFang TC", "Hiragino Sans GB", "Microsoft YaHei",
    "Noto Sans SC", ui-sans-serif, system-ui, sans-serif;
  --content-width: 42rem;
}
*, *::before, *::after { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0;
  font-family: var(--font-sans);
  font-size: 1.0625rem;
  line-height: 1.75;
  color: var(--text);
  background: var(--bg);
  -webkit-font-smoothing: antialiased;
}
.page-shell { min-height: 100vh; }
.page-header {
  background: linear-gradient(135deg, #0f172a 0%, #1e3a5f 48%, #0f172a 100%);
  color: #f1f5f9;
  padding: clamp(2rem, 5vw, 3.25rem) 1.25rem clamp(2.5rem, 6vw, 4rem);
  position: relative;
  overflow: hidden;
}
.page-header::before {
  content: "";
  position: absolute;
  inset: 0;
  background: radial-gradient(ellipse 80% 50% at 80% -20%, rgba(41, 98, 255, 0.35), transparent),
    radial-gradient(ellipse 60% 40% at 10% 100%, rgba(56, 189, 248, 0.12), transparent);
  pointer-events: none;
}
.header-inner { max-width: 72rem; margin: 0 auto; position: relative; z-index: 1; }
.eyebrow {
  font-size: 0.8125rem;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  opacity: 0.75;
  margin-bottom: 0.75rem;
}
h1.article-title {
  font-size: clamp(1.45rem, 4vw, 2.05rem);
  font-weight: 700;
  line-height: 1.3;
  margin: 0 0 1rem;
  max-width: 22em;
}
.meta-desc {
  font-size: 1rem;
  line-height: 1.65;
  color: rgba(241, 245, 249, 0.88);
  max-width: 42rem;
  margin: 0;
}
.doc-meta {
  margin: 1rem 0 0;
  font-size: 0.875rem;
  color: rgba(241, 245, 249, 0.72);
}
.skip-link {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border: 0;
}
.skip-link:focus {
  position: fixed;
  top: 0.75rem;
  left: 0.75rem;
  z-index: 100000;
  width: auto;
  height: auto;
  margin: 0;
  padding: 0.6rem 1rem;
  clip: auto;
  overflow: visible;
  background: var(--surface);
  color: var(--text);
  border: 2px solid var(--accent);
  border-radius: 8px;
  font-weight: 600;
  text-decoration: none;
}
.layout {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 2rem;
  max-width: 72rem;
  margin: 0 auto;
  padding: 2rem 1.25rem 3rem;
}
@media (min-width: 920px) {
  .layout {
    grid-template-columns: 260px minmax(0, var(--content-width));
    align-items: stretch;
    gap: 3rem;
    padding: 2.5rem 1.5rem 4rem;
  }
}
.toc-panel {
  display: none;
}
@media (min-width: 920px) {
  .toc-panel {
    display: block;
    align-self: stretch;
  }
}
.toc-card {
  position: sticky;
  top: 1.25rem;
  max-height: calc(100vh - 2.5rem);
  overflow-y: auto;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1.25rem 1rem 1rem;
  box-shadow: var(--shadow);
}
.toc-title {
  font-size: 0.75rem;
  font-weight: 700;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  color: var(--text-muted);
  margin: 0 0 0.75rem;
}
.toc-list { list-style: none; margin: 0; padding: 0; }
.toc-list a {
  display: block;
  padding: 0.4rem 0.35rem;
  font-size: 0.875rem;
  color: var(--text);
  text-decoration: none;
  border-radius: 6px;
}
.toc-list a:hover, .toc-list a:focus-visible {
  background: var(--accent-soft);
  color: var(--accent);
}
.toc-depth-3 a { padding-left: 1.2rem; font-size: 0.8125rem; color: var(--text-muted); }
details.mobile-toc {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
}
@media (min-width: 920px) { details.mobile-toc { display: none; } }
details.mobile-toc summary {
  padding: 1rem 1.15rem;
  font-weight: 600;
  cursor: pointer;
  list-style: none;
}
details.mobile-toc summary::-webkit-details-marker { display: none; }
details.mobile-toc summary::after { content: "▾"; float: right; opacity: 0.55; }
details.mobile-toc .toc-list { padding: 0 1rem 1rem; }
.article {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: clamp(1.5rem, 3vw, 2.75rem);
  box-shadow: var(--shadow);
  overflow-wrap: anywhere;
}
.article .lead { font-size: 1.125rem; font-weight: 600; }
.article p { margin: 0 0 1.1em; }
.article strong { font-weight: 600; }
h2 {
  font-size: 1.32rem;
  font-weight: 700;
  margin: 2.1rem 0 0.75rem;
  line-height: 1.35;
  scroll-margin-top: 5.5rem;
  padding-bottom: 0.3rem;
  border-bottom: 1px solid var(--border);
}
.intro-block h2 { margin-top: 0; border-bottom: none; }
h3 {
  font-size: 1.08rem;
  font-weight: 650;
  margin: 1.45rem 0 0.55rem;
  scroll-margin-top: 5rem;
}
h4 { font-size: 1rem; font-weight: 600; margin: 1.1rem 0 0.45rem; }
ul.plain-list { margin: 0 0 1.15em; padding-left: 1.35rem; }
ul.plain-list li { margin-bottom: 0.4em; }
ol.step-list {
  counter-reset: s;
  list-style: none;
  padding: 0;
  margin: 1rem 0 1.25rem;
}
ol.step-list li {
  position: relative;
  padding-left: 2.5rem;
  margin-bottom: 1.1rem;
}
ol.step-list li::before {
  counter-increment: s;
  content: counter(s);
  position: absolute;
  left: 0;
  top: 0.05rem;
  width: 1.85rem;
  height: 1.85rem;
  border-radius: 8px;
  background: var(--accent);
  color: #fff;
  font-weight: 700;
  font-size: 0.8rem;
  display: flex;
  align-items: center;
  justify-content: center;
}
.note-box {
  background: linear-gradient(120deg, var(--accent-soft) 0%, transparent 55%);
  border-left: 4px solid var(--accent);
  padding: 1rem 1.1rem;
  border-radius: 0 var(--radius) var(--radius) 0;
  margin: 1.15rem 0;
}
.table-wrap {
  overflow-x: auto;
  margin: 0.75rem 0 1.4rem;
  border: 1px solid var(--border);
  border-radius: 10px;
  background: #fafbfd;
  -webkit-overflow-scrolling: touch;
}
.article table {
  width: 100%;
  min-width: 32rem;
  border-collapse: collapse;
  font-size: 0.93rem;
  line-height: 1.55;
}
.article th, .article td {
  border-bottom: 1px solid var(--border);
  padding: 0.65rem 0.8rem;
  vertical-align: top;
  text-align: left;
}
.article tr:last-child th, .article tr:last-child td { border-bottom: none; }
.article thead th {
  background: linear-gradient(180deg, #eef2fb, #e8edf7);
  font-weight: 650;
}
.myth-block {
  border: 1px solid var(--border);
  border-radius: 10px;
  padding: 0.95rem 1.05rem;
  margin: 0.85rem 0;
  background: #fafbfd;
}
.myth-block h4 { margin-top: 0; }
.faq-item { border-bottom: 1px solid var(--border); padding: 1.1rem 0; }
.faq-item:first-child { padding-top: 0; }
.faq-item:last-child { border-bottom: none; padding-bottom: 0; }
.faq-q { font-weight: 600; margin: 0 0 0.45rem; }
.faq-a { margin: 0; color: var(--text-muted); font-size: 0.98rem; }
/* ref-out：正文指向 tr-adingview.com 的 follow 外链；勿加 rel="nofollow" */
.article a.ref-out {
  color: var(--accent);
  text-decoration: underline;
  text-underline-offset: 0.18em;
  font-weight: 500;
}
.article a.ref-out:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 2px;
  border-radius: 2px;
}
.figure {
  margin: 1.25rem 0 1.5rem;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  overflow: hidden;
  background: #fafbfd;
}
.figure img {
  display: block;
  width: 100%;
  height: auto;
  vertical-align: middle;
}
.figure figcaption {
  padding: 0.7rem 0.9rem;
  font-size: 0.875rem;
  color: var(--text-muted);
  line-height: 1.55;
  border-top: 1px solid var(--border);
}
.risk-callout {
  border: 1px solid #c2410c;
  background: #fff7ed;
  border-radius: 10px;
  padding: 1rem 1.15rem;
  margin: 1.5rem 0;
}
.risk-callout h2 { border: none; margin-top: 0; color: #9a3412; }
.related-reading {
  margin-top: 2rem;
  padding-top: 1.5rem;
  border-top: 1px solid var(--border);
}
.related-reading h2 {
  border: none;
  margin-top: 0;
  font-size: 1.15rem;
}
.related-reading ul { margin: 0 0 1em; padding-left: 1.35rem; }
.related-reading li { margin-bottom: 0.45em; }