:root {
  --bg:#FFFFFF;
  --bg-panel:#F6F7F7;
  --bg-panel-2:#EEF1F0;
  --border:#E3E6E5;
  --border-strong:#D2D8D6;
  --accent:#0F7A6A;
  --accent-dark:#0A574C;
  --accent-tint:#DDF0EC;
  --field-a:#D5ECE7;
  --field-b:#DCE1FB;
  --field-c:#EEF6C9;
  --field-d:#FADCE7;
  --text:#141A19;
  --text-muted:#5E6866;
  --text-faint:#8A9391;
  --success:#1F8A4C;
  --warn:#B7791F;
  --error:#C53A3A;
  --success-ink:#176738;
  --warn-ink:#805013;
  --on-accent:#FFFFFF;
  --clear:transparent;
  --grid-line:rgba(20,26,25,.06);
  --sheen:rgba(255,255,255,.6);
  --sheet:rgba(255,255,255,.44);
  --sheet-edge:rgba(255,255,255,.82);
  --veil:rgba(20,26,25,.22);
  --shadow-card:0 1px 2px rgba(20,26,25,.05),0 12px 30px -16px rgba(20,26,25,.18);
  --shadow-card-hover:0 2px 4px rgba(20,26,25,.06),0 20px 40px -18px rgba(20,26,25,.24);
  --shadow-float:0 1px 3px rgba(20,26,25,.08),0 14px 30px -12px rgba(20,26,25,.26);
  --shadow-seg:0 1px 2px rgba(20,26,25,.10),0 2px 6px -2px rgba(20,26,25,.10);
  --shadow-btn:0 1px 2px rgba(10,87,76,.24),0 8px 18px -8px rgba(10,87,76,.5);
  --ring:0 0 0 3px var(--accent-tint);
  --radius:8px;
  --radius-lg:11px;
  --radius-sm:6px;
  --radius-xs:4px;
  --radius-pill:999px;
  --radius-round:50%;
  --font-display:'Inter','Noto Sans SC','PingFang SC','Microsoft YaHei',system-ui,sans-serif;
  --font-body:'Inter','Noto Sans SC','PingFang SC','Hiragino Sans GB','Microsoft YaHei',system-ui,sans-serif;
  --font-mono:'JetBrains Mono',ui-monospace,'SFMono-Regular',Menlo,Consolas,monospace;
  --wrap:1280px;
  --reading:840px;
  --gutter:24px;
  --gut:max(var(--gutter),calc((100vw - var(--wrap)) / 2));
  --gap:20px;
  --header-height:68px;
  --space-section:96px;
  --ease:cubic-bezier(.2,.65,.3,1);
  --fast:150ms;
  --reveal-time:550ms;
}
*,*::before,*::after {box-sizing:border-box}
html {-webkit-text-size-adjust:100%;scroll-behavior:smooth;scroll-padding-top:calc(var(--header-height) + 24px)}
body {margin:0;background:var(--bg);color:var(--text);font-family:var(--font-body);font-size:16px;line-height:1.6;-webkit-font-smoothing:antialiased}
html.nav-open {overflow:hidden}
[hidden] {display:none!important}
img,svg {max-width:100%;vertical-align:middle}
img {height:auto}
button,input,select,textarea {font:inherit}
button {cursor:pointer}
button,a {-webkit-tap-highlight-color:var(--clear)}
button {color:var(--text)}
a {color:inherit;text-underline-offset:3px}
a:hover {text-decoration-thickness:2px}
:focus-visible {outline:2px solid var(--accent);outline-offset:3px}
::selection {background:var(--accent-tint);color:var(--accent-dark)}
h1,h2,h3,h4 {font-family:var(--font-display);line-height:1.25;text-wrap:balance}
h1 {font-size:clamp(34px,calc(2.4vw + 14px),48px);font-weight:900;letter-spacing:-.015em}
h2 {font-size:clamp(25px,3vw,34px);font-weight:800;letter-spacing:-.015em}
h3 {font-size:20px;font-weight:800}
p {margin:0 0 1em}
h1,h2,h3,h4 {margin:0 0 .65em}
ul,ol {padding-left:1.5em}
li + li {margin-top:.3em}
code,kbd,pre {font-family:var(--font-mono)}
code {font-size:.88em;overflow-wrap:anywhere}
:not(pre)>code {background:var(--bg-panel);color:var(--text);padding:2px 5px;border-radius:var(--radius-xs)}
pre {max-width:100%;min-width:0;overflow-x:auto;padding:22px;background:var(--bg-panel);color:var(--text);border:1px solid var(--border);border-radius:var(--radius);font-size:13px;line-height:1.85;tab-size:2}
pre code {font-size:inherit;white-space:pre;overflow-wrap:normal;word-break:normal}
hr {border:0;border-top:1px solid var(--border);margin:32px 0}
.wrap {width:100%;max-width:calc(var(--wrap) + var(--gutter)*2);margin-inline:auto;padding-inline:var(--gutter)}
.reading {width:100%;max-width:calc(var(--reading) + var(--gutter)*2);margin-inline:auto;padding-inline:var(--gutter)}
.section {padding-top:var(--space-section);padding-bottom:var(--space-section)}
.section-head {display:flex;align-items:flex-end;justify-content:space-between;gap:24px;margin-bottom:32px}
.section-head p {margin-bottom:0;color:var(--text-muted)}
.grid {display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:var(--gap)}
.grid>*,
.split>*,
.footer-grid>*,
.feature-row>* {min-width:0}
.split {display:grid;grid-template-columns:minmax(0,1fr) minmax(0,1fr);gap:64px;align-items:center}
.muted {color:var(--text-muted)}
.accent {color:var(--accent)}
.keep {white-space:nowrap}
.sr-only {position:absolute;width:1px;height:1px;margin:-1px;padding:0;overflow:hidden;clip:rect(0 0 0 0);white-space:nowrap;border:0}
.skip-link {position:fixed;top:8px;left:var(--gutter);z-index:100;transform:translateY(-160%);padding:10px 16px;background:var(--bg);color:var(--accent-dark);border:1px solid var(--accent);border-radius:var(--radius)}
.skip-link:focus {transform:none}
.btn {appearance:none;display:inline-flex;align-items:center;justify-content:center;gap:9px;min-height:48px;padding:10px 24px;border:1px solid var(--clear);border-radius:var(--radius);font-family:var(--font-body);font-size:15.5px;font-weight:700;line-height:1.4;text-decoration:none;text-align:center;transition:background-color var(--fast),border-color var(--fast),box-shadow var(--fast)}
.btn svg {width:18px;height:18px;flex-shrink:0}
.btn-main {background:var(--accent);color:var(--on-accent);box-shadow:var(--shadow-btn)}
.btn-main:hover,.btn-main.is-hover {background:var(--accent-dark);color:var(--on-accent)}
.btn-main:active,.btn-main.is-active {background:var(--accent-dark);color:var(--on-accent);box-shadow:none}
.btn-ghost {background:var(--bg);color:var(--text);border-color:var(--border-strong)}
.btn-ghost:hover,.btn-ghost.is-hover {border-color:var(--text-muted)}
.btn.is-focus {outline:2px solid var(--accent);outline-offset:3px}
.btn:disabled,.btn[aria-disabled="true"] {background:var(--bg-panel-2);color:var(--text-muted);border-color:var(--border);box-shadow:none;cursor:not-allowed}
.btn-small {min-height:40px;padding:8px 16px;font-size:14px}
.cta-row {display:flex;flex-wrap:wrap;justify-content:center;gap:12px;margin-bottom:18px}
.more {flex-shrink:0;font-size:14.5px;font-weight:700;color:var(--accent);text-decoration:none}
.more:hover {color:var(--accent-dark);text-decoration:underline}
.card,.panel {min-width:0;padding:24px;background:var(--bg);color:var(--text);border:1px solid var(--border);border-radius:var(--radius);box-shadow:var(--shadow-card)}
.panel {background:var(--bg-panel);color:var(--text);box-shadow:none}
.card p:last-child,.panel p:last-child {margin-bottom:0}
.card h3 {font-size:18px}
.card p {font-size:14px;color:var(--text-muted)}
.prose {min-width:0}
.prose h2 {margin-top:2.8em}
.prose h3 {margin-top:1.8em}
.prose p,.prose li {line-height:1.9}
.prose a {color:var(--accent-dark)}
.prose img {display:block;margin:24px auto}
.prose section {scroll-margin-top:calc(var(--header-height) + 24px)}
.decorated,.hero,[data-hero-visual] {overflow-x:clip}
.reveal {opacity:1;transform:none}
.reveal-ready .reveal:not(.shown) {opacity:0;transform:translateY(14px)}
.reveal-ready .reveal {transition:opacity var(--reveal-time) var(--ease),transform var(--reveal-time) var(--ease)}
.reveal.shown {opacity:1;transform:none}

/* 页头独立宽版心，不与阅读栏共用。 */
#site-header,.topbar {position:sticky;top:0;z-index:60;background:var(--bg);color:var(--text);border-bottom:1px solid var(--border)}
.topbar-in {width:100%;max-width:min(100%,calc(1280px + var(--gutter)*2));height:var(--header-height);margin-inline:auto;padding-inline:var(--gutter);display:flex;align-items:center;gap:32px;position:relative}
.brand {display:inline-flex;align-items:center;gap:11px;text-decoration:none;font-family:var(--font-display);font-weight:800;font-size:18px;letter-spacing:-.01em;color:var(--text);flex-shrink:0}
.brand img {display:block;width:34px;height:34px;flex-shrink:0}
.mainnav {margin-left:auto;min-width:0}
.mainnav ul {display:flex;align-items:center;list-style:none;margin:0;padding:0;gap:30px}
.mainnav li {margin:0}
.mainnav a {display:block;text-decoration:none;white-space:nowrap;font-size:14.5px;font-weight:500;color:var(--text-muted);padding:6px 0;transition:color var(--fast)}
.mainnav a:hover {color:var(--text)}
.mainnav a[aria-current="page"] {color:var(--text);font-weight:700}
.header-tools {display:flex;align-items:center;gap:12px;flex-shrink:0}
.language-box {position:relative}
.lang {appearance:none;border:0;border-left:1px solid var(--border);background:var(--bg);color:var(--text);cursor:pointer;font:inherit;font-size:14.5px;font-weight:600;padding:8px 0 8px 26px;min-height:44px;white-space:nowrap}
.lang .chevron {color:var(--text-muted);margin-left:2px}
.lang-short {display:none}
.language-menu {position:absolute;right:0;top:calc(100% + 10px);width:196px;padding:8px;list-style:none;margin:0;background:var(--bg);color:var(--text);border:1px solid var(--border);border-radius:var(--radius);box-shadow:var(--shadow-float);z-index:4}
.language-menu li {margin:0}
.language-menu a {display:flex;align-items:center;min-height:44px;padding:8px 12px;text-decoration:none;border-radius:var(--radius-xs)}
.language-menu a:hover,.language-menu a[aria-current="true"] {background:var(--bg-panel);color:var(--accent-dark)}
.menu-toggle {display:none;align-items:center;justify-content:center;min-width:44px;min-height:44px;padding:10px;background:var(--bg);color:var(--text);border:1px solid var(--border);border-radius:var(--radius)}
.menu-toggle svg {width:20px;height:20px}
.mobile-drawer {position:absolute;inset:100% 0 auto;z-index:3;max-height:calc(100dvh - var(--header-height));overflow-y:auto;overscroll-behavior:contain;background:var(--bg);color:var(--text);border-bottom:1px solid var(--border);padding:12px var(--gutter) 24px}
.mobile-drawer ul {list-style:none;margin:0;padding:0}
.mobile-drawer li {margin:0}
.mobile-drawer a {display:flex;align-items:center;width:100%;min-height:46px;padding:11px 12px;text-decoration:none;font-weight:600}
.mobile-drawer a:hover,.mobile-drawer a[aria-current] {background:var(--bg-panel);color:var(--accent-dark)}
.drawer-languages {border-top:1px solid var(--border);margin-top:12px!important;padding-top:12px!important}
.menu-veil {position:fixed;inset:var(--header-height) 0 0;z-index:1;border:0;background:var(--veil);color:var(--text);cursor:default}
.mobile-drawer,.header-tools,.brand,.mainnav {z-index:2}
.mobile-drawer {z-index:3}

/* 用户确认的首屏尺度与卡廊。 */
.hero {padding-top:46px;padding-bottom:18px}
.hero-copy {padding-inline:var(--gutter);display:flex;flex-direction:column;align-items:center;text-align:center}
.tag {display:inline-flex;align-items:center;gap:9px;min-height:30px;padding:3px 14px 3px 12px;border:1px solid var(--border);border-radius:var(--radius-pill);background:var(--bg-panel);color:var(--text-muted);font-size:13px;font-weight:600;margin:0 0 22px;max-width:100%}
.tag i {width:8px;height:8px;border-radius:var(--radius-round);background:var(--accent);flex-shrink:0}
.tag b {font-family:var(--font-mono);font-weight:600;color:var(--text);font-size:12.5px}
.hero h1 {margin:0 0 24px;font-weight:900;font-size:clamp(30px,calc(2.4vw + 14px),48px);line-height:1.15;letter-spacing:-.015em;color:var(--text)}
.hero h1 .ln {display:block}
.hero h1 em {font-style:normal;color:var(--accent)}
.lede {margin:0 0 18px;max-width:720px;font-size:15.5px;line-height:1.65;color:var(--text-muted)}
.lede strong {color:var(--text);font-weight:700}
.os-row {display:flex;flex-wrap:wrap;justify-content:center;align-items:center;gap:8px 28px;margin:0 0 38px;padding:0;list-style:none}
.os-row li {margin:0}
.os-row .os-lead {font-size:13px;color:var(--text-muted);font-weight:500}
.os-row a {display:inline-flex;align-items:center;gap:7px;text-decoration:none;font-size:13.5px;font-weight:600;color:var(--text-muted)}
.os-row a svg {width:16px;height:16px;display:block;flex-shrink:0}
.os-row a:hover {color:var(--accent)}
.facts {background:var(--bg-panel);color:var(--text);border-top:1px solid var(--border);border-bottom:1px solid var(--border)}
.facts ul {min-height:58px;padding:12px var(--gut);margin:0;list-style:none;display:flex;flex-wrap:wrap;align-items:center;justify-content:space-between;gap:10px 28px;font-family:var(--font-mono);font-size:12.5px}
.facts li {display:inline-flex;align-items:center;gap:9px;margin:0}
.facts i {width:7px;height:7px;border-radius:var(--radius-round);background:var(--accent);flex-shrink:0}
.facts span {color:var(--text-muted)}
.quick {padding:96px var(--gut) 112px}
.quick-head {display:flex;align-items:flex-end;justify-content:space-between;gap:24px;margin-bottom:32px}
.quick-head h2 {margin:0;font-size:30px;font-weight:800;letter-spacing:-.015em;line-height:1.25}
.quick-head p {margin:8px 0 0;color:var(--text-muted);font-size:15px}
.steps {display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:var(--gap)}
.step {min-width:0;padding:24px 24px 26px;background:var(--bg);color:var(--text);border:1px solid var(--border);border-radius:var(--radius);box-shadow:var(--shadow-card)}
.step small {display:inline-block;font-family:var(--font-mono);font-size:11.5px;font-weight:600;color:var(--accent-dark);background:var(--accent-tint);border-radius:var(--radius-xs);padding:2px 8px;margin-bottom:14px}
.step h3 {margin:0 0 6px;font-size:17px;font-weight:800}
.step p {margin:0;font-size:14px;color:var(--text-muted)}
.site-footer {border-top:1px solid var(--border);padding-top:64px;padding-bottom:88px;background:var(--bg);color:var(--text)}
.footer-grid {display:grid;grid-template-columns:1.3fr 1fr 1.1fr .7fr;gap:40px}
.footer-brand p {max-width:290px;margin-top:16px;font-size:14px;color:var(--text-muted)}
.site-footer h2 {font-size:14px;letter-spacing:0;margin-bottom:16px}
.site-footer ul {list-style:none;margin:0;padding:0}
.site-footer li {margin:0 0 9px}
.site-footer li a {font-size:14px;color:var(--text-muted);text-decoration:none}
.site-footer li a:hover {color:var(--accent-dark);text-decoration:underline}
.footer-bottom {display:flex;flex-wrap:wrap;justify-content:space-between;gap:16px;margin-top:40px;padding-top:24px;border-top:1px solid var(--border);font-size:13px;color:var(--text-muted)}
.footer-legal {display:flex;gap:20px}
@media (max-width:1080px) {
  .topbar-in {gap:20px}
  .mainnav ul {gap:20px}
}
@media (max-width:1000px) {
  .mainnav {display:none}
  .header-tools {margin-left:auto}
  .menu-toggle {display:inline-flex}
  .footer-grid {grid-template-columns:repeat(2,minmax(0,1fr))}
}
@media (min-width:1001px) {
  .mobile-drawer,.menu-veil {display:none!important}
}
@media (max-width:900px) {
  .steps,.grid {grid-template-columns:1fr}
  .split {grid-template-columns:1fr;gap:32px}
  .quick-head,.section-head {flex-direction:column;align-items:flex-start}
}
@media (max-width:768px) {
  h1,.hero h1 {font-size:clamp(24px,4vw,30px)}
}
@media (max-width:640px) {
  :root {--gutter:20px;--space-section:64px}
  .brand {font-size:16px;gap:8px}
  .brand img {width:30px;height:30px}
  .topbar-in {gap:8px}
  .header-tools {gap:6px;margin-left:auto}
  .lang {padding-left:12px}
  .lang-full {display:none}
  .lang-short {display:inline}
  .hero {padding-top:34px}
  .tag {font-size:12px}
  .lede {font-size:14.5px}
  .os-row {gap:10px 18px;margin-bottom:28px}
  .os-row .os-lead {flex-basis:100%}
  .facts ul {justify-content:flex-start}
  .quick {padding-top:64px;padding-bottom:80px}
  .quick-head h2 {font-size:24px}
  .footer-grid {grid-template-columns:1fr;gap:28px}
  .tilt,[data-tilt] {transform:none!important}
  pre {padding:16px;font-size:12px}
}
@media (max-width:360px) {
  :root {--gutter:16px}
  .brand {font-size:14px}
  .brand img {width:28px;height:28px}
  .btn {padding-inline:18px}
}
@media (prefers-reduced-motion:reduce) {
  html {scroll-behavior:auto}
  *,*::before,*::after {transition:none!important;animation:none!important;scroll-behavior:auto!important}
  .reveal-ready .reveal:not(.shown) {opacity:1;transform:none}
}