:root {
  --c-bg: #f4f4f6;
  --c-bg-clear: rgba(244, 244, 246, 0);
  --c-panel: #ffffff;
  --c-panel-2: #ebebf0;
  --c-panel-veil: rgba(255, 255, 255, 0.72);
  --c-border: #dcdce4;
  --c-border-veil: rgba(18, 18, 24, 0.08);
  --c-accent: #2152ff;
  --c-accent-dark: #1236c7;
  --c-accent-soft: #e9eeff;
  --c-text: #121218;
  --c-muted: #5c5c6b;
  --c-faint: #a4a4b3;
  --c-success: #1d9a68;
  --c-success-ink: #146b49;
  --c-warn: #f2721c;
  --c-warn-deep: #c2530d;
  --c-warn-ink: #a34108;
  --c-warn-soft: #fdeee2;
  --c-error: #d6383f;
  --c-error-ink: #ae252e;
  --c-clear: transparent;
  --c-veil: rgba(18, 18, 24, 0.28);

  --g-peach: #f6c3a6;
  --g-pink: #eebde0;
  --g-lilac: #cdc5f2;
  --g-sky: #a9dcf3;

  --f-pink: #e7b6ea;
  --f-pink-tint: #fbf1fb;
  --f-blue: #b6c8f7;
  --f-blue-tint: #eff3fe;
  --f-peach: #f3c4a6;
  --f-peach-tint: #fdf2eb;

  --line-callout: rgba(18, 18, 24, 0.34);
  --ring: rgba(33, 82, 255, 0.35);
  --shadow-float: 0 1px 2px rgba(18, 18, 24, 0.04), 0 4px 14px -6px rgba(18, 18, 24, 0.08);
  --shadow-btn: 0 1px 2px rgba(18, 18, 24, 0.06), 0 8px 18px -8px rgba(33, 82, 255, 0.55);
  --shadow-bar: 0 1px 3px rgba(18, 18, 24, 0.05), 0 14px 30px -14px rgba(18, 18, 24, 0.12), 0 30px 70px -22px rgba(214, 118, 68, 0.32);

  --font-display: "Inter", "Noto Sans SC", -apple-system, BlinkMacSystemFont, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
  --font-body: "Inter", "Noto Sans SC", -apple-system, BlinkMacSystemFont, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
  --font-mono: "JetBrains Mono", ui-monospace, "SF Mono", Menlo, Consolas, monospace;
  --weight-normal: 400;
  --weight-medium: 500;
  --weight-semibold: 600;
  --weight-bold: 700;
  --weight-display: 800;

  --r-xs: 6px;
  --r-sm: 8px;
  --r-logo: 8px;
  --r-btn: 10px;
  --r-shot: 10px;
  --r-tile: 16px;
  --r-card: 16px;
  --r-bar: 20px;
  --r-frame: 28px;
  --r-pill: 999px;

  --gutter: 32px;
  --wrap: 1240px;
  --reading: 820px;
  --nav-h: 68px;
  --section-space: 140px;
  --ease: 180ms ease;
  --reveal-time: 600ms;
}

*, *::before, *::after { box-sizing: border-box; }
html {
  -webkit-text-size-adjust: 100%;
  scroll-behavior: smooth;
  scroll-padding-top: calc(var(--nav-h) + 24px);
}
html.nav-open { overflow: hidden; }
body {
  margin: 0;
  background: var(--c-bg);
  color: var(--c-text);
  font-family: var(--font-body);
  font-size: 16px;
  line-height: 1.6;
  font-weight: var(--weight-normal);
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}
[hidden] { display: none !important; }
img { max-width: 100%; }
svg { display: block; flex-shrink: 0; }
button, input, select, textarea { font: inherit; }
button { cursor: pointer; }
a { color: var(--c-accent); text-decoration-thickness: 1px; text-underline-offset: 0.2em; }
a:hover { color: var(--c-accent-dark); }
button, a { -webkit-tap-highlight-color: var(--c-clear); }
:focus-visible { outline: 3px solid var(--ring); outline-offset: 3px; }
::selection { background: var(--c-accent-soft); color: var(--c-text); }
h1, h2, h3, h4 {
  font-family: var(--font-display);
  font-weight: var(--weight-display);
  line-height: 1.25;
  letter-spacing: -0.02em;
  text-wrap: balance;
  overflow-wrap: break-word;
}
h1 { font-size: clamp(34px, 3.2vw + 2px, 48px); line-height: 1.15; }
h2 { font-size: clamp(26px, 2.4vw, 36px); }
h3 { font-size: clamp(21px, 1.9vw, 28px); }
p, ul, ol, dl { margin-top: 0; }
strong { font-weight: var(--weight-bold); }
code, pre, kbd { font-family: var(--font-mono); }
code { overflow-wrap: anywhere; }
pre {
  max-width: 100%;
  min-width: 0;
  overflow-x: auto;
  padding: 22px;
  border: 1px solid var(--c-border);
  border-radius: var(--r-card);
  background: var(--c-panel);
  color: var(--c-text);
  font-size: 14px;
  line-height: 1.8;
  overscroll-behavior-inline: contain;
}
pre code { white-space: pre; overflow-wrap: normal; word-break: normal; }
.wrap {
  width: 100%;
  max-width: var(--wrap);
  margin-inline: auto;
  padding-inline: var(--gutter);
}
.reading { max-width: calc(var(--reading) + var(--gutter) * 2); }
.section { padding-top: var(--section-space); padding-bottom: var(--section-space); }
.section + .section { padding-top: 0; }
.stack > * + * { margin-top: 24px; }
.grid { display: grid; gap: 24px; }
.grid > *, .zz > *, .footer-grid > *, .topbar__inner > * { min-width: 0; }
.grid--two { grid-template-columns: repeat(2, minmax(0, 1fr)); }
.grid--three { grid-template-columns: repeat(3, minmax(0, 1fr)); }
.nowrap { white-space: nowrap; }
.muted { color: var(--c-muted); }
.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip-path: inset(50%);
  white-space: nowrap;
  border: 0;
}
.skip {
  position: absolute;
  left: -9999px;
  top: 8px;
  z-index: 60;
  padding: 8px 14px;
  background: var(--c-panel);
  color: var(--c-accent);
  border-radius: var(--r-sm);
}
.skip:focus { left: 16px; }
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 9px;
  min-height: 52px;
  padding: 12px 26px;
  border: 1px solid var(--c-clear);
  border-radius: var(--r-btn);
  font-family: var(--font-body);
  font-size: 16px;
  font-weight: var(--weight-bold);
  line-height: 1.5;
  letter-spacing: -0.005em;
  text-decoration: none;
  text-align: center;
  transition: background-color var(--ease), border-color var(--ease), color var(--ease);
}
.btn svg { width: 18px; height: 18px; }
.btn--primary {
  background: var(--c-accent);
  color: var(--c-panel);
  box-shadow: var(--shadow-btn);
}
.btn--primary:hover, .btn--primary.is-hover {
  background: var(--c-accent-dark);
  color: var(--c-panel);
}
.btn--ghost {
  background: var(--c-panel);
  color: var(--c-text);
  border-color: var(--c-border);
  box-shadow: var(--shadow-float);
}
.btn--ghost:hover, .btn--ghost.is-hover { border-color: var(--c-muted); color: var(--c-text); }
.btn:active { box-shadow: none; }
.btn:disabled, .btn[aria-disabled="true"] {
  background: var(--c-panel-2);
  color: var(--c-muted);
  border-color: var(--c-border);
  box-shadow: none;
  cursor: not-allowed;
}
.btn.is-focus { outline: 3px solid var(--ring); outline-offset: 3px; }
.actions { display: flex; flex-wrap: wrap; gap: 14px; align-items: center; }

#site-header, .topbar {
  position: sticky;
  top: 0;
  z-index: 40;
  background: var(--c-panel);
  color: var(--c-text);
  border-bottom: 1px solid var(--c-border);
}
.topbar__inner {
  height: var(--nav-h);
  width: 100%;
  max-width: min(100%, calc(1280px + var(--gutter) * 2));
  margin-inline: auto;
  padding-inline: var(--gutter);
  display: flex;
  align-items: center;
  gap: 28px;
}
.brand {
  display: inline-flex;
  align-items: center;
  gap: 11px;
  flex-shrink: 0;
  color: var(--c-text);
  text-decoration: none;
}
.brand:hover { color: var(--c-text); }
.brand__mark {
  display: block;
  width: 34px;
  height: 34px;
  flex-shrink: 0;
  border-radius: var(--r-logo);
}
.brand__mark--placeholder {
  border: 1.5px solid var(--c-clear);
  background:
    linear-gradient(var(--c-panel), var(--c-panel)) padding-box,
    linear-gradient(135deg, var(--c-accent), var(--g-lilac)) border-box;
  color: var(--c-text);
  box-shadow: var(--shadow-float);
}
.brand__name {
  font-family: var(--font-display);
  font-weight: var(--weight-display);
  font-size: 16.5px;
  letter-spacing: -0.01em;
  white-space: nowrap;
}
.mainnav { margin-left: auto; min-width: 0; }
.mainnav__list {
  display: flex;
  align-items: center;
  list-style: none;
  gap: 2px;
  margin: 0;
  padding: 0;
}
.navlink {
  display: inline-flex;
  align-items: center;
  gap: 7px;
  min-height: 38px;
  padding: 8px 12px;
  border-radius: var(--r-sm);
  color: var(--c-muted);
  font-size: 14.5px;
  font-weight: var(--weight-medium);
  text-decoration: none;
  white-space: nowrap;
  transition: background-color var(--ease), color var(--ease);
}
.navlink svg { width: 16px; height: 16px; }
.navlink:hover { background: var(--c-panel-2); color: var(--c-text); }
.navlink[aria-current="page"] {
  background: var(--c-accent-soft);
  color: var(--c-accent);
  font-weight: var(--weight-semibold);
}
.header-tools { display: flex; align-items: center; gap: 8px; flex-shrink: 0; }
.language { position: relative; }
.lang {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 7px;
  min-height: 38px;
  padding: 8px 14px;
  border: 1px solid var(--c-border);
  border-radius: var(--r-sm);
  background: var(--c-panel);
  color: var(--c-text);
  font-size: 14px;
  font-weight: var(--weight-medium);
  text-decoration: none;
  white-space: nowrap;
}
.lang svg { width: 15px; height: 15px; color: var(--c-muted); }
.lang__caret { font-size: 11px; color: var(--c-muted); }
.lang__short { display: none; }
.language__list {
  position: absolute;
  right: 0;
  top: calc(100% + 10px);
  min-width: 190px;
  margin: 0;
  padding: 8px;
  list-style: none;
  border: 1px solid var(--c-border);
  border-radius: var(--r-card);
  background: var(--c-panel);
  color: var(--c-text);
  box-shadow: var(--shadow-float);
  z-index: 4;
}
.language__list a {
  display: flex;
  align-items: center;
  width: 100%;
  min-height: 44px;
  padding: 10px 14px;
  color: var(--c-text);
  text-decoration: none;
  border-radius: var(--r-sm);
}
.language__list a:hover, .language__list a[aria-current="true"] {
  background: var(--c-accent-soft);
  color: var(--c-accent-dark);
}
.menu-toggle {
  display: none;
  align-items: center;
  justify-content: center;
  min-width: 44px;
  min-height: 44px;
  padding: 10px;
  border: 1px solid var(--c-border);
  border-radius: var(--r-sm);
  background: var(--c-panel);
  color: var(--c-text);
}
.menu-toggle svg { width: 22px; height: 22px; }
.mobile-drawer {
  position: absolute;
  top: var(--nav-h);
  left: 0;
  right: 0;
  z-index: 3;
  padding: 16px var(--gutter) 24px;
  max-height: calc(100dvh - var(--nav-h));
  overflow-y: auto;
  overscroll-behavior: contain;
  background: var(--c-panel);
  color: var(--c-text);
  border-bottom: 1px solid var(--c-border);
}
.mobile-drawer ul { list-style: none; margin: 0; padding: 0; }
.mobile-drawer a {
  display: flex;
  align-items: center;
  gap: 10px;
  width: 100%;
  min-height: 48px;
  padding: 12px 16px;
  border-radius: var(--r-sm);
  color: var(--c-text);
  text-decoration: none;
}
.mobile-drawer a svg { width: 18px; height: 18px; color: var(--c-warn); }
.mobile-drawer a:hover, .mobile-drawer a[aria-current] {
  background: var(--c-accent-soft);
  color: var(--c-accent-dark);
}
.mobile-drawer__label { margin: 20px 16px 8px; font-size: 13px; color: var(--c-muted); }
.nav-veil {
  position: fixed;
  inset: var(--nav-h) 0 0;
  z-index: 1;
  border: 0;
  background: var(--c-veil);
  color: var(--c-text);
  cursor: default;
}
.preview-menu { display: none; }
.preview-menu summary { list-style: none; }
.preview-menu summary::-webkit-details-marker { display: none; }

.hero {
  position: relative;
  isolation: isolate;
  overflow-x: clip;
  padding-top: 76px;
  text-align: center;
}
.hero__field {
  position: absolute;
  inset: 0 0 auto;
  height: max(600px, 72vh);
  z-index: -1;
  overflow: hidden;
  pointer-events: none;
}
.hero__field-layer {
  position: absolute;
  inset: 0 auto 0 0;
  width: 140%;
  background: linear-gradient(90deg, var(--g-peach) 0%, var(--g-pink) 30%, var(--g-lilac) 58%, var(--g-sky) 86%, var(--g-sky) 100%);
  color: var(--c-text);
  animation: field-drift 30s ease-in-out infinite;
}
.hero__field::after {
  content: "";
  position: absolute;
  inset: 0;
  background: linear-gradient(180deg, var(--c-bg-clear) 0%, var(--c-bg-clear) 34%, var(--c-bg) 100%);
  color: var(--c-text);
}
@keyframes field-drift {
  0%, 100% { transform: translateX(0); }
  50% { transform: translateX(-28.5%); }
}
.hero__kicker {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  min-height: 30px;
  padding: 3px 14px;
  border-radius: var(--r-pill);
  background: var(--c-panel-veil);
  color: var(--c-text);
  border: 1px solid var(--c-border-veil);
  font-size: 13px;
  font-weight: var(--weight-semibold);
}
.hero__kicker-dot {
  width: 7px;
  height: 7px;
  flex-shrink: 0;
  border-radius: var(--r-pill);
  background: var(--c-accent);
  color: var(--c-panel);
}
.hero__title {
  margin: 22px auto 0;
  font-size: clamp(34px, 3.2vw + 2px, 48px);
  line-height: 1.15;
  letter-spacing: -0.02em;
}
.hero__title > span { display: block; }
.hero__desc {
  max-width: 660px;
  margin: 20px auto 0;
  font-size: 17.5px;
  line-height: 1.68;
  color: var(--c-muted);
}
.hero__desc strong { color: var(--c-text); }
.hero__actions {
  display: flex;
  justify-content: center;
  gap: 14px;
  margin-top: 32px;
}
.card, .panel {
  padding: 28px;
  background: var(--c-panel);
  color: var(--c-text);
  border: 1px solid var(--c-border);
  border-radius: var(--r-card);
  box-shadow: var(--shadow-float);
  min-width: 0;
}
.card h3 { margin: 0 0 14px; }
.card p { color: var(--c-muted); }
.card > :last-child, .panel > :last-child { margin-bottom: 0; }
.frame { padding: 48px; border: 1px solid var(--c-border); border-radius: var(--r-frame); min-width: 0; }
.frame--pink { background: var(--f-pink-tint); color: var(--c-text); border-color: var(--f-pink); }
.frame--blue { background: var(--f-blue-tint); color: var(--c-text); border-color: var(--f-blue); }
.frame--peach { background: var(--f-peach-tint); color: var(--c-text); border-color: var(--f-peach); }
.caps { padding-top: var(--section-space); padding-bottom: var(--section-space); }
.caps__kicker {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 10px;
  margin: 0;
  font-size: 13.5px;
  font-weight: var(--weight-bold);
  letter-spacing: 0.08em;
  color: var(--c-warn-ink);
}
.caps__kicker::before, .caps__kicker::after {
  content: "";
  width: 22px;
  height: 1px;
  flex-shrink: 0;
  background: var(--f-peach);
  color: var(--c-text);
}
.caps__title {
  margin: 14px auto 0;
  max-width: 820px;
  text-align: center;
  font-size: clamp(24px, 2.2vw, 34px);
}
.zz {
  display: grid;
  grid-template-columns: minmax(0, 1fr) minmax(0, 1.08fr);
  align-items: center;
  gap: 80px;
  margin-top: 80px;
}
.zz + .zz { margin-top: var(--section-space); }
.zz--reverse .zz__visual { order: -1; }
.tile {
  display: inline-flex;
  justify-content: center;
  align-items: center;
  width: 56px;
  height: 56px;
  flex-shrink: 0;
  border: 1px solid var(--f-pink);
  border-radius: var(--r-tile);
  background: var(--f-pink-tint);
  color: var(--c-warn);
}
.tile--blue { background: var(--f-blue-tint); color: var(--c-warn); border-color: var(--f-blue); }
.tile--peach { background: var(--f-peach-tint); color: var(--c-warn); border-color: var(--f-peach); }
.tile svg { width: 28px; height: 28px; }
.zz__title { margin: 24px 0 0; font-size: 30px; }
.zz__body { max-width: 520px; margin: 16px 0 0; color: var(--c-muted); font-size: 16.5px; line-height: 1.8; }
.deeplink { display: inline-flex; align-items: center; gap: 6px; margin-top: 22px; font-weight: var(--weight-bold); text-decoration: none; }
.compact-row { margin-top: 80px; }
.kw {
  font-family: var(--font-mono);
  font-size: 0.9em;
  padding: 1px 6px;
  border-radius: var(--r-xs);
  background: var(--c-panel-2);
  color: var(--c-text);
}
.kw--policy { background: var(--c-warn-soft); color: var(--c-warn-ink); }
.prose, .article-body { min-width: 0; line-height: 1.9; }
.prose h2, .article-body h2 { margin-top: 64px; }
.prose h3, .article-body h3 { margin-top: 36px; }
.prose p, .article-body p { margin-bottom: 22px; }
.prose :not(pre) > code, .article-body :not(pre) > code {
  background: var(--c-panel-2);
  color: var(--c-text);
  padding: 2px 5px;
  border-radius: var(--r-xs);
  font-size: 0.9em;
}
.prose li + li, .article-body li + li { margin-top: 8px; }
.reveal { opacity: 1; transform: none; }
.reveal-ready .reveal {
  transition: opacity var(--reveal-time) ease, transform var(--reveal-time) ease;
}
.reveal-ready .reveal:not(.shown) { opacity: 0; transform: translateY(16px); }
.reveal-ready .reveal.shown { opacity: 1; transform: none; }

.site-footer {
  margin-top: var(--section-space);
  padding-top: 64px;
  padding-bottom: 32px;
  border-top: 1px solid var(--c-border);
  background: var(--c-panel);
  color: var(--c-text);
}
.footer-grid { display: grid; grid-template-columns: 1.5fr 0.8fr 1.2fr 0.7fr; gap: 40px; }
.footer-brand p { margin-top: 20px; max-width: 340px; color: var(--c-muted); font-size: 14px; }
.footer-title { margin: 0 0 18px; font-size: 15px; font-weight: var(--weight-bold); }
.footer-links { list-style: none; margin: 0; padding: 0; }
.footer-links a { display: inline-block; padding-block: 6px; color: var(--c-muted); font-size: 14px; text-decoration: none; overflow-wrap: anywhere; }
.footer-links a:hover, .footer-links a[aria-current] { color: var(--c-accent); }
.footer-bottom {
  margin-top: 48px;
  padding-top: 24px;
  border-top: 1px solid var(--c-border);
  display: flex;
  flex-wrap: wrap;
  justify-content: space-between;
  gap: 16px 28px;
  font-size: 13px;
  color: var(--c-muted);
}
.footer-bottom p { margin: 0; }
.footer-legal { display: flex; flex-wrap: wrap; gap: 18px; }
.footer-legal a { color: var(--c-muted); text-decoration: none; }

@media (max-width: 1200px) {
  .mainnav { display: none; }
  .header-tools { margin-left: auto; }
  .menu-toggle { display: inline-flex; }
  .preview-menu { display: block; }
}
@media (min-width: 1201px) {
  .mobile-drawer, .nav-veil { display: none !important; }
}
@media (max-width: 1020px) {
  .zz { grid-template-columns: minmax(0, 1fr); gap: 40px; }
  .zz--reverse .zz__visual { order: 0; }
  .grid--three { grid-template-columns: minmax(0, 1fr); }
  .footer-grid { grid-template-columns: repeat(2, minmax(0, 1fr)); }
}
@media (max-width: 768px) {
  :root { --gutter: 20px; }
  h1, .hero__title { font-size: clamp(24px, 4vw, 30px); }
  .topbar__inner { gap: 12px; }
  .brand { flex: 1 1 auto; min-width: 0; }
  .brand__name { font-size: 15px; min-width: 0; overflow: hidden; text-overflow: ellipsis; }
  .header-tools { flex-shrink: 0; }
  .hero { padding-top: 48px; }
  .hero__desc { font-size: 16px; }
  .hero__actions { flex-direction: column; align-items: stretch; max-width: 320px; margin-inline: auto; }
  .frame { padding: 24px; }
  .grid--two { grid-template-columns: minmax(0, 1fr); }
}
@media (max-width: 640px) {
  .tilt, [data-tilt] { transform: none !important; }
  .card, .panel { padding: 22px; }
  .footer-grid { grid-template-columns: minmax(0, 1fr); gap: 32px; }
  .zz { gap: 32px; }
  .zz__title { font-size: 26px; }
  .hero__title > span { display: block; }
  .lang__txt { display: none; }
  .lang__short { display: inline; }
  .lang { min-width: 48px; min-height: 44px; padding-inline: 10px; }
  .lang > svg { display: none; }
  .topbar__inner { gap: 8px; }
}
@media (max-width: 380px) {
  :root { --gutter: 16px; }
  .brand { gap: 7px; }
  .brand__mark { width: 28px; height: 28px; }
  .brand__name { font-size: 12px; }
  .header-tools { gap: 4px; }
  .frame { padding: 18px; }
}
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  .hero__field-layer { animation: none; transform: none; }
  .reveal-ready .reveal:not(.shown) { opacity: 1; transform: none; }
  *, *::before, *::after { transition: none !important; }
}
@media print {
  #site-header, .topbar, .site-footer, .dl-fab { display: none !important; }
  .reveal-ready .reveal:not(.shown) { opacity: 1; transform: none; }
}