:root{--brand:#2aabee;--brand-dark:#1683c2;--brand-soft:#eaf6fd;--text:#212529;--muted:#5f6670;--line:#ebebeb;--bg:#f8f9fa;--radius:12px}
*{box-sizing:border-box}
html{-webkit-text-size-adjust:100%;scroll-behavior:smooth}
body{margin:0;font-family:-apple-system,BlinkMacSystemFont,"Segoe UI","PingFang SC","Hiragino Sans GB","Microsoft YaHei",Roboto,"Helvetica Neue",Arial,sans-serif;color:var(--text);background:#fff;line-height:1.8;font-size:16px}
img{max-width:100%;height:auto;display:block}
a{color:var(--brand-dark);text-decoration:none}
a:hover{text-decoration:underline}
.tg-wrap{max-width:1080px;margin:0 auto;padding:0 20px}
.tg-skip{position:absolute;left:-9999px;top:0;background:var(--brand);color:#fff;padding:8px 16px;z-index:100}
.tg-skip:focus{left:0}
/* header */
.tg-site-header{position:sticky;top:0;z-index:50;background:rgba(255,255,255,.96);border-bottom:1px solid var(--line);backdrop-filter:saturate(180%) blur(8px)}
.tg-header-inner{display:flex;align-items:center;justify-content:space-between;height:64px}
.tg-logo{display:flex;align-items:center;gap:10px;font-weight:700;font-size:18px;color:var(--text)}
.tg-logo:hover{text-decoration:none}
.tg-logo-mark{flex:none}
.tg-logo-text{display:flex;flex-direction:column;line-height:1.2}
.tg-logo-name{font-size:18px;font-weight:700}
.tg-logo-tag{font-size:12px;font-weight:400;color:var(--muted);letter-spacing:.5px;margin-top:2px}
.tg-site-nav ul{list-style:none;margin:0;padding:0;display:flex;gap:4px}
.tg-site-nav a{display:block;padding:8px 12px;border-radius:8px;color:var(--text);font-size:15px}
.tg-site-nav a:hover{background:var(--brand-soft);color:var(--brand-dark);text-decoration:none}
.tg-site-nav a[aria-current=page]{color:var(--brand-dark);font-weight:600}
.tg-nav-toggle{position:absolute;opacity:0;pointer-events:none}
.tg-nav-btn{display:none;cursor:pointer;padding:10px}
.tg-nav-btn span{display:block;width:22px;height:2px;background:var(--text);margin:4px 0;border-radius:2px}
/* hero */
.tg-hero{background:linear-gradient(180deg,var(--brand-soft) 0%,#fff 100%);padding:28px 0 32px}
.tg-hero-home{padding:48px 0 40px}
.tg-hero h1{font-size:34px;line-height:1.35;margin:8px 0 8px;letter-spacing:.5px}
.tg-hero-home h1{font-size:40px}
.tg-lead{font-size:17px;color:#343a40;max-width:860px;margin:12px 0 0}
.tg-meta{color:var(--muted);font-size:14px;margin:0;display:flex;flex-wrap:wrap;gap:4px 16px}
.tg-hero-actions{display:flex;flex-wrap:wrap;gap:12px;margin-top:22px}
.tg-btn{display:inline-block;white-space:nowrap;cursor:pointer;background:var(--brand);color:#fff;padding:12px 26px;border-radius:999px;font-weight:600;font-size:16px;border:2px solid var(--brand);transition:background .2s}
.tg-btn:hover{background:var(--brand-dark);border-color:var(--brand-dark);text-decoration:none}
.tg-btn-ghost{background:#fff;color:var(--brand-dark)}
.tg-btn-ghost:hover{background:var(--brand-soft);color:var(--brand-dark)}
.tg-breadcrumb ol{list-style:none;margin:0;padding:0;display:flex;flex-wrap:wrap;font-size:14px;color:var(--muted)}
.tg-breadcrumb li+li::before{content:"/";margin:0 8px;color:#adb5bd}
.tg-breadcrumb a{color:var(--muted)}
/* banner (home) */
.tg-banner{position:relative;overflow:hidden;padding:56px 0 48px}
.tg-banner-inner{display:grid;gap:36px;align-items:center}
.tg-banner h1{font-size:46px;line-height:1.25;margin:0 0 12px;letter-spacing:.5px}
.tg-banner .tg-lead{font-size:18px}
.tg-banner-art img{width:100%;height:auto}
.tg-banner-chips{list-style:none;padding:0;margin:24px 0 0;display:flex;flex-wrap:wrap;gap:10px}
.tg-banner-chips a{display:inline-block;padding:7px 18px;border-radius:999px;background:#fff;border:1px solid var(--line);color:var(--text);font-size:14px}
.tg-banner-chips a:hover{border-color:var(--brand);color:var(--brand-dark);text-decoration:none}
.tg-side-toc .tg-toc{border:0;padding:0}
/* 结构选项用到的通用样式 */
.tg-strip{padding:22px 0;border-bottom:1px solid var(--line)}
.tg-strip .tg-cards{margin:0}
.tg-hero-grid{display:grid;grid-template-columns:1.15fr 1fr;gap:36px;align-items:center}
.tg-hero-pic{margin:0}
.tg-hero-pic img{border-radius:var(--radius)}
.tg-layout-side{display:grid;grid-template-columns:minmax(0,1fr) 250px;gap:48px;max-width:1180px}
.tg-layout-side.tg-side-left{grid-template-columns:230px minmax(0,1fr)}
.tg-layout-side .tg-content{max-width:none}
.tg-side-toc{position:sticky;top:84px;align-self:start;margin-top:8px;font-size:14px;max-height:calc(100vh - 110px);overflow:auto}
.tg-side-toc .tg-toc ol{columns:1;list-style:none;padding:0;margin:0}
.tg-side-toc .tg-toc li{margin:0 0 8px}
/* content */
.tg-layout{padding:24px 20px 56px}
.tg-content{max-width:860px}
.tg-content h2{font-size:26px;line-height:1.4;margin:44px 0 14px;padding-left:12px;border-left:4px solid var(--brand)}
.tg-content h3{font-size:19px;margin:26px 0 8px}
.tg-content p{margin:0 0 14px}
.tg-content ul,.tg-content ol{padding-left:24px;margin:0 0 16px}
.tg-content li{margin:6px 0}
.tg-summary{background:var(--bg);border:1px solid var(--line);border-radius:var(--radius);padding:18px 22px;margin:8px 0 24px}
.tg-summary-title,.tg-toc-title{font-weight:700;margin:0 0 6px}
.tg-summary ul{margin:0}
.tg-hero-figure{margin:0 0 24px}
.tg-hero-figure img{border-radius:var(--radius);border:1px solid var(--line)}
.tg-hero-figure figcaption{font-size:13px;color:var(--muted);text-align:center;margin-top:8px}
.tg-toc{border:1px solid var(--line);border-radius:var(--radius);padding:16px 22px;margin:0 0 8px}
.tg-toc ol{margin:0;columns:2;column-gap:32px}
.tg-toc li{break-inside:avoid;font-size:15px}
.tg-steps{counter-reset:s;list-style:none;padding-left:0}
.tg-steps>li{counter-increment:s;position:relative;padding-left:42px;margin:12px 0}
.tg-steps>li::before{content:counter(s);position:absolute;left:0;top:2px;width:28px;height:28px;border-radius:50%;background:var(--brand);color:#fff;font-weight:700;font-size:14px;display:flex;align-items:center;justify-content:center}
.tg-table-wrap{overflow-x:auto;margin:0 0 16px;border:1px solid var(--line);border-radius:var(--radius)}
table{width:100%;border-collapse:collapse;font-size:15px;min-width:560px}
caption{text-align:left;font-weight:600;padding:12px 16px;color:var(--muted);font-size:14px}
th,td{padding:12px 16px;border-top:1px solid var(--line);text-align:left;vertical-align:top}
thead th{background:var(--bg);font-weight:600}
.tg-cards{display:grid;grid-template-columns:repeat(3,1fr);gap:14px;margin:0 0 16px}
.tg-card{display:block;border:1px solid var(--line);border-radius:var(--radius);padding:16px 18px;color:var(--text);transition:border-color .2s,box-shadow .2s}
.tg-card:hover{border-color:var(--brand);box-shadow:0 4px 14px rgba(255,105,51,.12);text-decoration:none}
.tg-card strong{display:block;font-size:17px;color:var(--brand-dark)}
.tg-card span{font-size:14px;color:var(--muted)}
.tg-note{font-size:14px;color:var(--muted)}
pre{background:#1f2328;color:#f0f3f6;padding:14px 16px;border-radius:10px;overflow-x:auto;font-size:14px;line-height:1.6;margin:8px 0 14px}
code{font-family:Consolas,"SFMono-Regular",Menlo,monospace}
.tg-faq-item{border-bottom:1px solid var(--line);padding:6px 0 4px}
.tg-faq-item h3{margin:14px 0 6px;font-size:18px}
.tg-related{margin-top:48px;background:var(--bg);border-radius:var(--radius);padding:20px 24px}
.tg-related h2{border:0;padding:0;margin:0 0 8px;font-size:20px}
.tg-related ul{margin:0}
/* footer */
.tg-site-footer{background:#1f2328;color:#c9d1d9;padding:40px 0 24px;font-size:14px}
.tg-site-footer a{color:#c9d1d9}
.tg-site-footer a:hover{color:#fff}
.tg-footer-grid{display:grid;grid-template-columns:2fr 1fr 1fr 1fr;gap:28px}
.tg-footer-logo{display:flex;align-items:center;gap:10px;font-weight:700;font-size:16px;color:#fff;margin:0 0 8px}
.tg-footer-title{color:#fff;font-weight:600;margin:0 0 8px}
.tg-site-footer ul{list-style:none;margin:0;padding:0}
.tg-site-footer li{margin:4px 0}
.tg-footer-note{border-top:1px solid #30363d;margin-top:28px;padding-top:16px;color:#8b949e;font-size:13px}
.tg-footer-note p{margin:0 0 6px}
/* responsive */
@media (max-width:960px){
.tg-hero-grid{grid-template-columns:1fr}
.tg-layout-side,.tg-layout-side.tg-side-left{grid-template-columns:minmax(0,1fr);gap:0}
.tg-side-toc{display:none}
.tg-nav-btn{display:block}
.tg-site-nav{display:none;position:absolute;top:64px;left:0;right:0;background:#fff;border-bottom:1px solid var(--line);box-shadow:0 8px 16px rgba(0,0,0,.06)}
.tg-site-nav ul{flex-direction:column;padding:8px 12px}
.tg-nav-toggle:checked~.tg-site-nav{display:block}
}
@media (max-width:640px){
.tg-banner h1{font-size:30px}
.tg-banner .tg-lead{font-size:16px}
.tg-banner{padding:36px 0 28px}
.tg-hero h1,.tg-hero-home h1{font-size:26px}
.tg-lead{font-size:16px}
.tg-content h2{font-size:22px}
.tg-toc ol{columns:1}
.tg-cards{grid-template-columns:1fr 1fr}
.tg-footer-grid{grid-template-columns:1fr 1fr}
.tg-footer-about{grid-column:1/-1}
}

/* 骨架 paperplane（2026-11-12 重做）：参考 Telegram 官网的气质——白底、细体字、居中大标题、
   横幅下并排的大号蓝色平台链接、几乎无装饰、细线分隔、多栏文字页脚。不使用官方 logo 与图形。 */
body{font-family:"Helvetica Neue","Helvetica Light",Helvetica,"PingFang SC","Hiragino Sans GB","Microsoft YaHei",Roboto,Arial,sans-serif;font-size:15px;color:#222;line-height:1.75}
a{color:var(--brand-dark)}
/* 页头：一行细小的文字导航 */
.tg-site-header{background:#fff;border-bottom:1px solid #e8e8e8;backdrop-filter:none}
.tg-header-inner{height:56px}
.tg-logo-name{font-size:17px;font-weight:600}
.tg-logo-tag{font-size:11px;color:#8a8a8a}
.tg-site-nav ul{gap:2px}
.tg-site-nav a{color:#555;font-size:14px;padding:6px 10px;border-radius:0}
.tg-site-nav a:hover{background:none;color:var(--brand-dark);text-decoration:none}
.tg-site-nav a[aria-current=page]{color:var(--brand-dark);font-weight:400}
/* 首页横幅：纯白，细体大标题居中，平台链接并排 */
.tg-banner{background:radial-gradient(ellipse 60% 70% at 50% 0%,rgba(42,171,238,.16),transparent 70%),linear-gradient(180deg,#e9f4fc 0%,#f4f9fd 55%,#fff 100%);text-align:center;padding:76px 0 24px;border-bottom:1px solid #e3eef6}
.tg-banner-inner{grid-template-columns:1fr;justify-items:center;gap:6px}
.tg-banner h1{font-size:50px;font-weight:300;letter-spacing:0;color:#222;line-height:1.25}
.tg-banner .tg-meta{justify-content:center;color:#a0a0a0;font-size:13px}
.tg-banner .tg-lead{color:#6d6d6d;font-size:17px;max-width:680px;margin:14px auto 0;font-weight:300}
.tg-banner .tg-hero-actions{justify-content:center;margin-top:26px}
.tg-banner-chips{justify-content:center;gap:0;margin-top:30px}
.tg-banner-chips li{border-right:1px solid #e3e3e3}
.tg-banner-chips li:last-child{border-right:0}
.tg-banner-chips a{background:none;border:0;border-radius:0;padding:4px 22px;font-size:19px;font-weight:300;color:var(--brand-dark)}
.tg-banner-chips a:hover{text-decoration:underline;color:var(--brand-dark)}
.tg-banner-art{max-width:780px;width:100%;margin-top:34px}
/* 按钮：实心蓝圆角，次按钮只是文字链接 */
.tg-btn{background:var(--brand);border:0;border-radius:22px;padding:11px 30px;font-weight:400;font-size:15px;box-shadow:none}
.tg-btn:hover{background:var(--brand-dark)}
.tg-btn-ghost{background:none;color:var(--brand-dark);padding:11px 14px}
.tg-btn-ghost:hover{background:none;text-decoration:underline}
/* 子页首屏：白底，左对齐细体标题，下方一条细线 */
.tg-hero{background:#fff;padding:34px 0 26px;border-bottom:1px solid #e8e8e8}
.tg-hero h1{font-size:32px;font-weight:300;color:#222}
.tg-hero .tg-lead{color:#6d6d6d;font-weight:300}
.tg-breadcrumb ol{font-size:13px}
.tg-hero .tg-wrap{max-width:800px}
.tg-hero-figure{max-width:620px;margin:8px auto 26px}
/* 正文：单栏居中，细体 H2，无装饰 */
.tg-layout{padding-top:20px}
.tg-content{max-width:760px;margin:0 auto}
.tg-content h2{border:0;padding:0;font-size:26px;font-weight:300;color:#222;margin:52px 0 12px}
.tg-content h3{font-size:16px;font-weight:600;margin:22px 0 6px}
.tg-content p,.tg-content li{color:#333}
.tg-summary{background:none;border:0;border-top:1px solid #e8e8e8;border-bottom:1px solid #e8e8e8;border-radius:0;padding:14px 0;margin:14px 0 28px}
.tg-summary-title{font-weight:600;font-size:14px;color:#8a8a8a}
.tg-summary li{margin:4px 0}
.tg-hero-figure img{border:0;border-radius:6px}
.tg-hero-figure figcaption{color:#a0a0a0}
.tg-steps>li::before{background:none;color:var(--brand-dark);font-weight:300;font-size:22px;width:auto;height:auto;top:-2px}
.tg-steps>li{padding-left:30px}
.tg-table-wrap{border:0;border-radius:0;border-top:1px solid #e8e8e8}
table{font-size:14px}
th,td{border-top:0;border-bottom:1px solid #eeeeee;padding:10px 12px}
thead th{background:#fff;color:#8a8a8a;font-weight:600;font-size:13px}
caption{padding:10px 0;color:#a0a0a0;font-weight:400}
pre{background:#f7f7f7;color:#222;border:1px solid #ececec;border-radius:4px}
/* FAQ：像官网 FAQ 页那样，粗体问题 + 正文回答 */
.tg-faq-item{border:0;padding:0}
.tg-faq-item h3{font-size:16px;font-weight:600;color:#222;margin:20px 0 4px}
.tg-faq-item p{color:#555}
/* 延伸阅读：一行一行的文字链接 */
.tg-related{background:none;border-top:1px solid #e8e8e8;border-radius:0;padding:18px 0 0;margin-top:54px}
.tg-related h2{font-size:15px;font-weight:600;color:#8a8a8a;margin:0 0 6px}
.tg-related ul{list-style:none;padding:0;columns:2}
.tg-related li{margin:4px 0}
/* 页脚：白底多栏文字链接 */
.tg-site-footer{background:#fff;color:#808080;border-top:1px solid #e8e8e8;padding:36px 0 22px;font-size:13px}
.tg-site-footer a{color:#808080}
.tg-site-footer a:hover{color:var(--brand-dark);text-decoration:none}
.tg-footer-logo{color:#222;font-size:15px}
.tg-footer-title{color:#222;font-weight:600;font-size:13px}
.tg-footer-note{border-top:1px solid #eeeeee;color:#a0a0a0;font-size:12px}
@media (max-width:960px){
.tg-site-nav{top:56px;border-bottom:1px solid #e8e8e8;box-shadow:none}
}
@media (max-width:640px){
.tg-banner{padding-top:44px}
.tg-banner h1{font-size:32px}
.tg-banner-chips{gap:6px 0}
.tg-banner-chips li{border-right:0;width:50%}
.tg-banner-chips a{font-size:16px;padding:4px 8px}
.tg-related ul{columns:1}
.tg-hero h1{font-size:26px}
}