/* =========================================================
   Telegram 官方下载站（简体默认・繁體可切换）
   设计系统：借鉴 telegram.org 官网 —— 纯白留白、官方品牌蓝、
   居中 Logo 首屏、下载卡片式布局、轻盈悬浮交互
   作者：TG Dev Team
   ========================================================= */

:root{
  /* 品牌色（对齐 telegram.org 官方品牌蓝） */
  --brand:#2AABEE;
  --brand-2:#229ED9;
  --brand-deep:#168AC1;
  --brand-ink:#0D6E9E;
  --link:#0088cc;
  --grad:linear-gradient(135deg,#2AABEE,#229ED9);
  --brand-soft:rgba(42,171,238,.10);
  --brand-soft-2:rgba(42,171,238,.16);

  /* 中性色 */
  --ink:#17212B;
  --text:#54677A;
  --muted:#8496A8;
  --navy:#17212B;
  --navy-2:#1F2B37;

  /* 背景与描边 */
  --bg:#FFFFFF;
  --bg-soft:#F5F9FC;
  --bg-tint:#EAF5FB;
  --line:rgba(23,33,43,.08);
  --line-strong:rgba(23,33,43,.14);

  /* 阴影 */
  --shadow-sm:0 1px 2px rgba(23,33,43,.04),0 2px 8px rgba(23,33,43,.05);
  --shadow-md:0 8px 28px rgba(23,33,43,.09);
  --shadow-lg:0 24px 64px rgba(23,33,43,.16);
  --shadow-brand:0 10px 30px rgba(42,171,238,.30);

  /* 圆角 */
  --r-sm:12px;
  --r-md:16px;
  --r-lg:20px;
  --r-xl:28px;
  --r-pill:999px;

  --container:1140px;
  --header-h:64px;
  --font:"Inter","SF Pro Text",-apple-system,BlinkMacSystemFont,"Segoe UI","PingFang HK","PingFang TC","Microsoft JhengHei","Noto Sans HK","Noto Sans TC",Roboto,"Helvetica Neue",Arial,sans-serif;
}

/* ---------- 基础重置 ---------- */
*,*::before,*::after{box-sizing:border-box;margin:0;padding:0}
html{scroll-behavior:smooth;scroll-padding-top:84px}
body{
  font-family:var(--font);
  font-size:16px;
  line-height:1.65;
  color:var(--text);
  background:var(--bg);
  -webkit-font-smoothing:antialiased;
  text-rendering:optimizeLegibility;
}
img,svg{display:block;flex-shrink:0}
a{color:inherit;text-decoration:none}
button{font-family:inherit;cursor:pointer;background:none;border:none;color:inherit}
input{font-family:inherit}
ul,ol{list-style:none}
::selection{background:var(--brand-soft-2);color:var(--brand-ink)}

h1,h2,h3,h4{color:var(--ink);line-height:1.3;font-weight:800;letter-spacing:-.01em}

/* ---------- 布局 ---------- */
.container{width:100%;max-width:var(--container);margin:0 auto;padding:0 24px}
.section{padding:88px 0}
.section.tight{padding:56px 0}
.section.alt{background:var(--bg-soft);border-top:1px solid var(--line);border-bottom:1px solid var(--line)}
.section.tint{background:var(--bg-tint)}

.section-head{max-width:680px;margin:0 auto 52px;text-align:center}
.section-head h2{font-size:clamp(1.65rem,3vw,2.2rem);margin:16px 0 14px}
.section-head .lead{font-size:16.5px}

.lead{font-size:17px;line-height:1.8;color:var(--text)}
.muted{color:var(--muted)}
.hl{color:var(--brand-deep)}
.text-center{text-align:center}

.mt-8{margin-top:8px}.mt-16{margin-top:16px}.mt-24{margin-top:24px}
.mt-32{margin-top:32px}.mt-40{margin-top:40px}.mt-56{margin-top:56px}

/* ---------- 眉标 / 胶囊 ---------- */
.eyebrow{
  display:inline-flex;align-items:center;gap:8px;
  padding:6px 14px;border-radius:var(--r-pill);
  background:var(--brand-soft);color:var(--brand-ink);
  font-size:13px;font-weight:700;letter-spacing:.04em;
}
.eyebrow::before{content:"";width:6px;height:6px;border-radius:50%;background:var(--brand)}
.chip{
  display:inline-flex;align-items:center;gap:6px;
  padding:7px 14px;border-radius:var(--r-pill);
  background:#FFF;border:1px solid var(--line-strong);
  font-size:13.5px;font-weight:600;color:var(--text);
  box-shadow:var(--shadow-sm);
}
.chip svg{color:var(--brand-deep)}
.chip-row{display:flex;flex-wrap:wrap;gap:10px}
.pill{
  display:inline-flex;align-items:center;gap:6px;
  padding:4px 12px;border-radius:var(--r-pill);
  background:var(--brand-soft);color:var(--brand-ink);
  font-size:12.5px;font-weight:700;
}
.pill.blue{background:var(--brand-soft-2);color:var(--brand-deep)}

/* ---------- 按钮 ---------- */
.btn{
  display:inline-flex;align-items:center;justify-content:center;gap:8px;
  padding:12px 26px;border-radius:var(--r-pill);
  font-size:15px;font-weight:700;line-height:1.2;
  border:1px solid transparent;
  transition:transform .18s ease,box-shadow .18s ease,background .18s ease,color .18s ease,border-color .18s ease;
  white-space:nowrap;
}
.btn svg{width:16px;height:16px}
.btn-primary{
  background:var(--grad);color:#FFF;
  box-shadow:var(--shadow-brand);
}
.btn-primary:hover{transform:translateY(-2px);box-shadow:0 14px 34px rgba(42,171,238,.38)}
.btn-ghost{
  background:#FFF;color:var(--ink);
  border-color:var(--line-strong);box-shadow:var(--shadow-sm);
}
.btn-ghost:hover{border-color:var(--brand);color:var(--brand-deep);transform:translateY(-2px)}
.btn-light{
  background:#FFF;color:var(--brand-deep);
  box-shadow:0 10px 30px rgba(10,60,90,.18);
}
.btn-light:hover{transform:translateY(-2px)}
.btn-outline-light{
  background:rgba(255,255,255,.12);color:#FFF;
  border-color:rgba(255,255,255,.55);
}
.btn-outline-light:hover{background:rgba(255,255,255,.22);transform:translateY(-2px)}
.btn-lg{padding:15px 34px;font-size:16px}
.btn-sm{padding:9px 20px;font-size:14px}
.btn-block{width:100%}

.link-more{
  display:inline-flex;align-items:center;gap:8px;
  font-weight:700;color:var(--link);font-size:15.5px;
}
.link-more svg{width:17px;height:17px;transition:transform .18s ease}
.link-more:hover svg{transform:translateX(4px)}
.link-more:hover{color:var(--brand-deep)}

/* ---------- 顶部导航（官网式单行固定栏） ---------- */
.site-header{
  position:fixed;top:0;left:0;right:0;z-index:100;
  height:var(--header-h);
  background:rgba(255,255,255,.82);
  -webkit-backdrop-filter:blur(14px) saturate(1.6);
  backdrop-filter:blur(14px) saturate(1.6);
  border-bottom:1px solid transparent;
  transition:border-color .2s ease,box-shadow .2s ease,background .2s ease;
}
.site-header.scrolled{
  background:rgba(255,255,255,.94);
  border-bottom-color:var(--line);
  box-shadow:0 6px 24px rgba(23,33,43,.06);
}
.header-inner{height:var(--header-h);display:flex;align-items:center;gap:28px}
.brand{display:inline-flex;align-items:center;gap:10px;flex-shrink:0}
.brand-logo{
  width:34px;height:34px;border-radius:50%;
  background:var(--grad);color:#FFF;
  display:inline-flex;align-items:center;justify-content:center;
  box-shadow:0 4px 12px rgba(42,171,238,.35);
}
.brand-logo svg{width:20px;height:20px}
.brand-name{font-size:19px;font-weight:800;color:var(--ink);letter-spacing:-.02em}

.main-nav{display:flex;align-items:center;gap:4px;margin-left:auto}
.nav-link{
  padding:8px 15px;border-radius:var(--r-pill);
  font-size:15px;font-weight:600;color:var(--text);
  transition:color .18s ease,background .18s ease;
}
.nav-link:hover{color:var(--ink);background:rgba(23,33,43,.05)}
.nav-link.active{color:var(--brand-ink);background:var(--brand-soft)}
.header-actions{display:flex;align-items:center;gap:10px;margin-left:8px}

/* ---------- 语言切换（简体 / 繁體） ---------- */
.lang-switch{
  display:inline-flex;align-items:center;gap:2px;padding:3px;
  border-radius:var(--r-pill);background:var(--bg-soft);border:1px solid var(--line-strong);
}
.lang-btn{
  border:0;background:transparent;border-radius:var(--r-pill);
  padding:5px 12px;font-size:13px;font-weight:700;color:var(--muted);
  cursor:pointer;font-family:inherit;line-height:1.4;
  transition:background .18s ease,color .18s ease;
}
.lang-btn:hover{color:var(--brand-deep)}
.lang-btn.active{background:var(--brand-soft-2);color:var(--brand-ink)}

.nav-toggle{
  display:none;position:relative;width:40px;height:40px;
  border-radius:var(--r-pill);flex-direction:column;align-items:center;justify-content:center;gap:5px;
}
.nav-toggle span{display:block;width:19px;height:2px;border-radius:2px;background:var(--ink);transition:transform .22s ease,opacity .22s ease}
.nav-toggle.open span:nth-child(1){transform:translateY(7px) rotate(45deg)}
.nav-toggle.open span:nth-child(2){opacity:0}
.nav-toggle.open span:nth-child(3){transform:translateY(-7px) rotate(-45deg)}
@media(max-width:1024px){
  .main-nav{
    position:fixed;top:var(--header-h);left:0;right:0;
    flex-direction:column;align-items:stretch;gap:2px;
    background:#FFF;border-bottom:1px solid var(--line);
    padding:14px 20px 20px;margin-left:0;
    box-shadow:0 24px 40px rgba(23,33,43,.12);
    transform:translateY(-8px);opacity:0;pointer-events:none;
    transition:transform .22s ease,opacity .22s ease;
  }
  .main-nav.open{transform:translateY(0);opacity:1;pointer-events:auto}
  .nav-link{padding:12px 14px;font-size:16px}
  .nav-toggle{display:flex}
  .header-actions .hide-md{display:none}
}

/* ---------- 首页首屏（1:1 复刻 telegram.org 首页下载模块） ---------- */
.hero{
  padding:calc(var(--header-h) + 64px) 0 72px;
  text-align:center;position:relative;overflow:hidden;
}
.hero::before{
  content:"";position:absolute;inset:-30% -20% auto;
  height:640px;pointer-events:none;
  background:
    radial-gradient(560px 320px at 18% 10%,rgba(42,171,238,.10),transparent 70%),
    radial-gradient(640px 360px at 84% 6%,rgba(34,158,217,.12),transparent 70%);
}
.hero-inner{position:relative;z-index:1}

.clearfix::before,.clearfix::after{content:" ";display:table}
.clearfix::after{clear:both}

/* ---- Logo 区（tl_main_logo_wrap：精灵动画 logo + 字标 + 标语，尺寸/间距同官网） ---- */
.tl_main_logo_wrap{max-width:400px;margin:0 auto;padding:20px 0 20px}
a.tl_main_logo{display:block;line-height:0;text-decoration:none!important}
div.tl_main_logo{display:block;width:144px;height:144px;margin:-8px auto;animation:500ms steps(30) both;background-repeat:no-repeat;background-size:cover}
div.tl_main_logo.play{animation-name:t-logo-play}
@keyframes t-logo-play{from{background-position:0% 0%}to{background-position:100% 0%}}
.tl_main_logo_title_image{display:block;width:144px;height:36px;margin:18px auto 6px}
.tl_main_logo_lead{
  font-size:20px;line-height:148%;max-width:285px;margin:0 auto;color:#8c8c8c;
  text-align:center;padding:1px 0 10px;
  font-family:"HelveticaNeue-Light","Helvetica Neue Light","Helvetica Light",Helvetica,Arial,Verdana,sans-serif;font-weight:300;
}

/* ---- 下载瓦片区（tl_main_download_mobile：悬停播放演示视频 + 蓝色下划线动效） ---- */
.tl_main_download_mobile{text-align:center;max-width:1028px;margin:0 auto}
.tl_main_download_link{text-align:center;display:inline-block;height:300px;padding-top:262px;padding-bottom:20px;margin:40px 0;font-size:15px;line-height:18px;max-width:100%;position:relative;color:#0088cc}
a.tl_main_download_link:hover{text-decoration:none}
a.tl_main_download_link:after{
  display:block;height:3px;background:#179cde;position:absolute;border-radius:2px;content:"";left:4px;right:4px;opacity:0;bottom:-1px;
  transition:opacity .2s ease-in-out,transform .2s ease-in-out;transform-origin:bottom;transform:scaleX(.3) scaleY(0);
}
a.tl_main_download_link:hover:after{opacity:1;transform:scaleX(1) scaleY(1)}
.tl_main_download_link_android{width:28.210116857923%;min-width:245px}
.tl_main_download_link_ios{width:42.9961%;min-width:350px}
.tl_main_download_link_tdesktop{display:none;min-width:320px;background:url("../img/SiteTDesktop.webp") 50% 0 no-repeat}
.tl_main_download_image__ios,.tl_main_download_image__android{display:block;position:absolute;top:50%;left:50%;transform-origin:50% 50%;opacity:1;pointer-events:none;transition:opacity .1s ease-in-out;padding:0;border:0}
.tl_main_download_image__ios{margin:-150px 0 0 -152px;width:304px;height:240px;background:url("../img/SiteiOS.webp") 50% 0 no-repeat}
.tl_main_download_image__android{margin:-150px 0 0 -152px;width:304px;height:240px;background:url("../img/SiteAndroid.webp") 50% 0 no-repeat}
.tl_main_video_player{display:block;position:absolute;top:50%;left:50%;transform-origin:50% 50%;opacity:0;pointer-events:none;transition:opacity .1s ease-in-out;padding:0;border:0}
.tl_main_video_player.video__init_retina{display:none}
.tl_main_video_player__android{margin:-150px 0 0 -96px;width:192px;height:240px}
.tl_main_video_player__ios{margin:-150px 0 0 -152px;width:304px;height:240px}
.video_play .tl_main_video_player{opacity:1}
.tl_main_download_more_btn{
  font-weight:normal;text-align:center;vertical-align:middle;cursor:pointer;border:0;white-space:nowrap;
  padding:10px 22px;font-size:15px;line-height:1.33;user-select:none;
  color:#FFF;background-color:#318fd3;margin-top:5px;display:none;border-radius:999px;
}
.tl_main_download_more_btn:hover{color:#FFF}
.icon-arrow-more{display:inline-block;vertical-align:baseline;width:6px;height:11px;background:url("../img/tl_arrow.png") 0 0 no-repeat;margin-left:10px}

/* ---- 桌面下载区块（tl_main_download_desktop_section，>640px 显示） ---- */
.tl_main_download_desktop_header{text-align:center}
.tl_main_download_desktop_wrap1{height:291px;overflow:hidden}
.tl_main_download_desktop_wrap{position:absolute;left:0;right:0}
.tl_main_download_desktop{position:absolute;left:0;right:0;min-width:804px;background:url("../img/SiteDesktop.webp") 50% 19px no-repeat}
.tl_main_download_desktop_links{width:595px;margin:0 auto}
.tl_main_download_desktop_link{
  text-align:center;display:inline-block;padding:270px 0 20px;font-size:15px;line-height:18px;vertical-align:top;
  transition:box-shadow .2s ease-in-out;position:relative;float:left;color:#0088cc;
}
a.tl_main_download_desktop_link:hover{text-decoration:none}
a.tl_main_download_desktop_link:after{
  display:block;height:3px;background:#179cde;position:absolute;border-radius:2px;content:"";left:4px;right:4px;opacity:0;bottom:-1px;
  transition:opacity .2s ease-in-out,transform .2s ease-in-out;transform-origin:bottom;transform:scaleX(.3) scaleY(0);
}
a.tl_main_download_desktop_link:hover:after{opacity:1;transform:scaleX(1) scaleY(1)}
.tl_main_download_link_td{width:52%;padding-left:20px;padding-right:20px}
.tl_main_download_link_osx{width:48%}

/* ---- 平台图标（官网 theme 版：mask + currentColor，随链接蓝色） ---- */
.icon-android,.icon-ios{display:inline-block;vertical-align:text-top;width:25px;height:27px;margin-right:10px;margin-top:-6px;background:none;background-color:currentColor;-webkit-mask-repeat:no-repeat;mask-repeat:no-repeat;-webkit-mask-position:0 0;mask-position:0 0}
.tl_main_download_link .icon-android{-webkit-mask-image:url("../img/SiteIconAndroid.svg");mask-image:url("../img/SiteIconAndroid.svg");-webkit-mask-size:22px 27px;mask-size:22px 27px}
.tl_main_download_link .icon-ios{-webkit-mask-image:url("../img/SiteIconApple.svg");mask-image:url("../img/SiteIconApple.svg");-webkit-mask-size:21px 27px;mask-size:21px 27px}

/* ---- ≤640px 移动端（官网同款规则） ---- */
@media (max-width:640px){
  .hero-inner{padding-left:0;padding-right:0}
  .tl_main_download_mobile{padding:0 20px}
  .tl_main_download_link{width:auto;min-width:0;display:block;margin-top:20px;margin-bottom:30px}
  a.tl_main_download_link:after{display:none}
  .tl_main_download_link_ios{padding-top:210px;height:245px;padding-bottom:15px}
  .tl_main_download_image__ios{margin:-123px 0 0 -121px;background-size:360px 220px;width:248px;height:198px}
  .tl_main_video_player__ios{margin:-124px 0 0 -121px;width:248px;height:198px}
  .tl_main_download_link_tdesktop{display:block;padding-top:156px;height:188px}
  .tl_main_download_desktop_section,.tl_main_download_desktop_wrap1{display:none}
  .tl_main_download_more_btn{display:inline-block}
}

/* ---- ≤480px 移动端（官网同款规则：logo 缩小 + 标语缩小） ---- */
@media (max-width:480px){
  .tl_main_logo_wrap{padding-top:10px;padding-bottom:2px}
  div.tl_main_logo{width:100px!important;height:100px!important;margin:-5px auto}
  .tl_main_logo_lead{font-size:16px;max-width:224px}
}

/* ---- Retina 2x 素材（官网媒体查询） ---- */
@media only screen and (-webkit-min-device-pixel-ratio:1.5),only screen and (-o-min-device-pixel-ratio:3/2),only screen and (min--moz-device-pixel-ratio:1.5),only screen and (min-device-pixel-ratio:1.5){
  .icon-arrow-more{background-image:url("../img/tl_arrow_2x.png");background-size:6px 11px}
  .tl_main_download_desktop{background-image:url("../img/SiteDesktop_2x.webp");background-size:1246px 260px}
  .tl_main_download_image__android{background-image:url("../img/SiteAndroid_2x.webp");background-size:290px 270px}
  .tl_main_download_image__ios{background-image:url("../img/SiteiOS_2x.webp");background-size:442px 270px}
  .tl_main_download_link_tdesktop{background-image:url("../img/SiteTDesktop_2x.webp");background-size:320px 157px}
}

/* ---------- 内页页头 ---------- */
.page-hero{
  position:relative;overflow:hidden;
  padding:calc(var(--header-h) + 56px) 0 52px;
}
.page-hero::before{
  content:"";position:absolute;inset:-40% -20% auto;
  height:520px;pointer-events:none;
  background:
    radial-gradient(520px 280px at 16% 8%,rgba(42,171,238,.10),transparent 70%),
    radial-gradient(600px 320px at 86% 4%,rgba(34,158,217,.10),transparent 70%);
}
.page-hero .container{position:relative;z-index:1}
.page-hero h1{font-size:clamp(1.9rem,3.6vw,2.6rem);margin:18px 0 14px}
.page-hero .lead{max-width:720px}
.breadcrumbs{
  display:flex;align-items:center;gap:8px;flex-wrap:wrap;
  font-size:13.5px;color:var(--muted);
}
.breadcrumbs a{color:var(--muted);font-weight:600;transition:color .18s ease}
.breadcrumbs a:hover{color:var(--brand-deep)}
.breadcrumbs .sep{opacity:.55}
.breadcrumbs .cur{color:var(--brand-ink);font-weight:700}

/* ---------- 数据统计条 ---------- */
.stats-band{background:var(--bg-tint);border-top:1px solid var(--line);border-bottom:1px solid var(--line);padding:44px 0}
.stats-grid{display:grid;grid-template-columns:repeat(4,1fr);gap:24px;text-align:center}
.stat-num{
  font-size:clamp(1.6rem,3vw,2.1rem);font-weight:800;color:var(--ink);
  letter-spacing:-.02em;line-height:1.15;
}
.stat-num em{font-style:normal;color:var(--brand-deep)}
.stat-label{margin-top:6px;font-size:14px;color:var(--muted);font-weight:600}

/* ---------- 网格 ---------- */
.grid{display:grid;gap:22px}
.cols-2{grid-template-columns:repeat(2,1fr)}
.cols-3{grid-template-columns:repeat(3,1fr)}
.cols-4{grid-template-columns:repeat(4,1fr)}

/* ---------- 特性卡片 ---------- */
.feature-card{
  position:relative;padding:28px 26px;border-radius:var(--r-lg);
  background:#FFF;border:1px solid var(--line);
  box-shadow:var(--shadow-sm);
  transition:transform .2s ease,box-shadow .2s ease,border-color .2s ease;
}
.feature-card:hover{transform:translateY(-4px);box-shadow:var(--shadow-md);border-color:rgba(42,171,238,.35)}
.feature-icon{
  width:48px;height:48px;border-radius:14px;
  background:var(--brand-soft);color:var(--brand-deep);
  display:flex;align-items:center;justify-content:center;
  margin-bottom:18px;
}
.feature-icon svg{width:23px;height:23px}
.feature-card h3{font-size:17.5px;margin-bottom:9px}
.feature-card p{font-size:14.8px;line-height:1.75}

/* ---------- 分栏区块 ---------- */
.split{
  display:grid;grid-template-columns:1fr 1fr;gap:56px;align-items:center;
  padding:44px 0;
}
.split+.split{border-top:1px solid var(--line)}
.split--flip .split-copy{order:2}
.split--flip .split-media{order:1}
.split-copy h2{font-size:clamp(1.5rem,2.6vw,1.95rem);margin:16px 0 14px}
.check-list{display:grid;gap:12px;margin-top:22px}
.check-list li{display:flex;align-items:flex-start;gap:11px;font-size:15.3px;font-weight:600;color:var(--ink)}
.check{
  width:22px;height:22px;border-radius:50%;flex-shrink:0;margin-top:2px;
  background:var(--brand-soft);color:var(--brand-deep);
  display:inline-flex;align-items:center;justify-content:center;
}
.check svg{width:12px;height:12px}

/* 深色区块（私隐安全） */
.split--dark{background:var(--navy);padding:72px 0}
.split--dark .split{padding:0;border-top:none}
.split--dark .split-copy h2{color:#FFF}
.split--dark .split-copy p{color:rgba(255,255,255,.72)}
.split--dark .eyebrow{background:rgba(255,255,255,.10);color:#9FDCFF}
.split--dark .eyebrow::before{background:#57C8F5}
.split--dark .check-list li{color:rgba(255,255,255,.92)}
.split--dark .check{background:rgba(87,200,245,.16);color:#7FD4F8}

/* ---------- 视觉面板 / 插画 ---------- */
.panel{
  border-radius:var(--r-xl);background:#FFF;border:1px solid var(--line);
  box-shadow:var(--shadow-md);padding:26px;
}
.split--dark .panel{background:var(--navy-2);border-color:rgba(255,255,255,.08)}
.secure-card{
  display:flex;align-items:center;gap:15px;
  padding:20px;border-radius:var(--r-lg);
  background:linear-gradient(135deg,rgba(42,171,238,.10),rgba(34,158,217,.16));
  border:1px solid rgba(42,171,238,.25);
}
.split--dark .secure-card{background:linear-gradient(135deg,rgba(42,171,238,.16),rgba(34,158,217,.10));border-color:rgba(87,200,245,.28)}
.secure-icon{
  width:50px;height:50px;border-radius:50%;flex-shrink:0;
  background:var(--grad);color:#FFF;
  display:flex;align-items:center;justify-content:center;
  box-shadow:0 10px 24px rgba(42,171,238,.35);
}
.secure-icon svg{width:24px;height:24px}
.secure-card strong{display:block;font-size:15.5px;color:var(--ink);font-weight:800}
.split--dark .secure-card strong{color:#FFF}
.secure-sub{display:block;font-size:13px;color:var(--muted);margin-top:2px}

/* 聊天窗口模型 */
.mock-window{border-radius:var(--r-lg);border:1px solid var(--line);overflow:hidden;background:#FFF}
.mock-window-head{
  display:flex;align-items:center;gap:6px;padding:11px 15px;
  background:var(--bg-soft);border-bottom:1px solid var(--line);
}
.mock-window-head .dot{width:10px;height:10px;border-radius:50%}
.mock-window-title{margin-left:8px;font-size:12.5px;font-weight:700;color:var(--muted)}
.mock-row{display:flex;align-items:center;gap:12px;padding:13px 16px;border-bottom:1px solid var(--line)}
.mock-row:last-child{border-bottom:none}
.mock-row.active{background:var(--brand-soft)}
.avatar{
  width:40px;height:40px;border-radius:50%;flex-shrink:0;
  background:var(--grad);color:#FFF;font-size:13px;font-weight:800;
  display:inline-flex;align-items:center;justify-content:center;
}
.avatar.gray{background:linear-gradient(135deg,#9DB2C4,#7E93A6)}
.avatar.navy{background:linear-gradient(135deg,#3A5166,#2A3D50)}
.avatar-lg{width:48px;height:48px;font-size:17px}
.mock-info{flex:1;min-width:0}
.mock-info strong{display:block;font-size:14px;color:var(--ink);font-weight:700}
.mock-info em{display:block;font-size:12.5px;color:var(--muted);font-style:normal;overflow:hidden;text-overflow:ellipsis;white-space:nowrap}
.mock-time{font-size:11.5px;color:var(--muted);font-weight:600}

/* 频道帖子模型 */
.mock-post{border-radius:var(--r-lg);border:1px solid var(--line);background:#FFF;padding:20px}
.mock-post-head{display:flex;align-items:center;gap:13px}
.mock-post-head strong{display:block;font-size:15px;color:var(--ink);font-weight:800}
.mock-post-head em{display:block;font-size:12.5px;color:var(--muted);font-style:normal;margin-top:2px}
.mock-post-head .pill{margin-left:auto}
.mock-post-text{margin:16px 0;font-size:14.3px;line-height:1.75}
.file-card{
  display:flex;align-items:center;gap:13px;
  padding:14px 16px;border-radius:var(--r-md);
  background:var(--bg-soft);border:1px solid var(--line);
}
.file-icon{
  width:40px;height:40px;border-radius:12px;flex-shrink:0;
  background:#FFF;border:1px solid var(--line-strong);color:var(--brand-deep);
  display:flex;align-items:center;justify-content:center;
}
.file-icon svg{width:19px;height:19px}
.file-card strong{display:block;font-size:13.5px;color:var(--ink);font-weight:700}
.file-card em{display:block;font-size:12px;color:var(--muted);font-style:normal}
.file-dl{
  margin-left:auto;width:38px;height:38px;border-radius:50%;
  background:var(--grad);color:#FFF;flex-shrink:0;
  display:flex;align-items:center;justify-content:center;
  box-shadow:0 8px 18px rgba(42,171,238,.32);
}
.file-dl svg{width:17px;height:17px}

/* ---------- 手风琴（FAQ） ---------- */
.accordion{display:grid;gap:12px;max-width:860px;margin:0 auto}
.accordion-item{
  border:1px solid var(--line);border-radius:var(--r-md);
  background:#FFF;box-shadow:var(--shadow-sm);overflow:hidden;
  transition:border-color .2s ease,box-shadow .2s ease;
}
.accordion-item:hover{border-color:rgba(42,171,238,.35)}
.accordion-item.open{border-color:rgba(42,171,238,.5);box-shadow:var(--shadow-md)}
.accordion-head{
  width:100%;display:flex;align-items:center;gap:15px;
  padding:19px 22px;text-align:left;
  font-size:15.8px;font-weight:700;color:var(--ink);
}
.accordion-index{font-size:12.5px;font-weight:800;color:var(--brand);flex-shrink:0;width:24px}
.accordion-head>span:nth-child(2){flex:1}
.accordion-icon{
  position:relative;width:20px;height:20px;flex-shrink:0;
}
.accordion-icon::before,.accordion-icon::after{
  content:"";position:absolute;top:50%;left:50%;transform:translate(-50%,-50%);
  background:var(--brand-deep);border-radius:2px;transition:transform .22s ease,opacity .22s ease;
}
.accordion-icon::before{width:13px;height:2px}
.accordion-icon::after{width:2px;height:13px}
.accordion-item.open .accordion-icon::after{transform:translate(-50%,-50%) scaleY(0);opacity:0}
.accordion-body{max-height:0;overflow:hidden;transition:max-height .28s ease}
.accordion-content{
  padding:0 22px 21px 61px;font-size:14.8px;line-height:1.85;color:var(--text);
}
.accordion-content a{color:var(--link);font-weight:700}
.accordion-content a:hover{color:var(--brand-deep)}

/* ---------- 搜索 + 筛选标签 ---------- */
.search-box{
  position:relative;max-width:560px;margin:0 auto;
}
.search-box svg{
  position:absolute;left:18px;top:50%;transform:translateY(-50%);
  width:19px;height:19px;color:var(--muted);
}
.search-box input{
  width:100%;padding:15px 22px 15px 50px;
  border-radius:var(--r-pill);border:1px solid var(--line-strong);
  background:#FFF;font-size:15px;color:var(--ink);
  box-shadow:var(--shadow-sm);outline:none;
  transition:border-color .18s ease,box-shadow .18s ease;
}
.search-box input:focus{border-color:var(--brand);box-shadow:0 0 0 4px var(--brand-soft)}
.tabs{display:inline-flex;flex-wrap:wrap;justify-content:center;gap:8px}
.tab{
  padding:9px 20px;border-radius:var(--r-pill);
  background:#FFF;border:1px solid var(--line-strong);
  font-size:14px;font-weight:700;color:var(--text);
  transition:all .18s ease;
}
.tab:hover{border-color:var(--brand);color:var(--brand-deep)}
.tab.active{background:var(--brand-soft-2);border-color:transparent;color:var(--brand-ink)}
.filter-empty{text-align:center;padding:44px 0;color:var(--muted);font-weight:600}
.hidden{display:none !important}

/* ---------- 新闻卡片 ---------- */
.featured-post{
  display:grid;grid-template-columns:1.05fr 1.2fr;gap:0;
  border-radius:var(--r-xl);overflow:hidden;
  border:1px solid var(--line);background:#FFF;box-shadow:var(--shadow-md);
}
.post-cover{
  position:relative;min-height:200px;
  background:linear-gradient(135deg,#2AABEE,#229ED9);
  display:flex;align-items:center;justify-content:center;color:rgba(255,255,255,.9);
}
.post-cover svg{width:64px;height:64px}
.post-cover .tag{position:absolute;top:18px;left:18px}
.post-cover.v2{background:linear-gradient(135deg,#1F2B37,#2C4356)}
.post-cover.v3{background:linear-gradient(135deg,#229ED9,#0D6E9E)}
.tag{
  display:inline-flex;align-items:center;
  padding:5px 13px;border-radius:var(--r-pill);
  background:rgba(255,255,255,.92);color:var(--brand-ink);
  font-size:12px;font-weight:800;letter-spacing:.03em;
}
.featured-post .post-body{padding:34px 38px;display:flex;flex-direction:column;justify-content:center}
.post-meta{display:flex;align-items:center;gap:12px;font-size:12.5px;color:var(--muted);font-weight:600}
.post-meta .tag{background:var(--brand-soft);color:var(--brand-ink)}
.post-title{font-size:clamp(1.15rem,2vw,1.45rem);margin:12px 0 10px}
.post-card .post-title{font-size:17px}
.post-excerpt{font-size:14.6px;line-height:1.8}
.post-card{
  display:flex;flex-direction:column;border-radius:var(--r-lg);overflow:hidden;
  border:1px solid var(--line);background:#FFF;box-shadow:var(--shadow-sm);
  transition:transform .2s ease,box-shadow .2s ease,border-color .2s ease;
}
.post-card:hover{transform:translateY(-4px);box-shadow:var(--shadow-md);border-color:rgba(42,171,238,.35)}
.post-card .post-cover{min-height:150px}
.post-card .post-cover svg{width:46px;height:46px}
.post-card .tag{top:14px;left:14px}
.post-card .post-body{padding:22px 24px 24px;display:flex;flex-direction:column;gap:0;flex:1}
.post-card .post-excerpt{margin-top:9px}

/* ---------- 下载页：平台卡片 ---------- */
.platform-grid{display:grid;grid-template-columns:repeat(2,1fr);gap:22px}
.platform-card{
  position:relative;display:flex;flex-direction:column;
  padding:30px 30px 26px;border-radius:var(--r-xl);
  background:#FFF;border:1px solid var(--line);box-shadow:var(--shadow-sm);
  transition:transform .2s ease,box-shadow .2s ease,border-color .2s ease;
  scroll-margin-top:96px;
}
.platform-card:hover{transform:translateY(-4px);box-shadow:var(--shadow-md);border-color:rgba(42,171,238,.35)}
.platform-card.detected{border-color:var(--brand);box-shadow:0 12px 36px rgba(42,171,238,.22)}
.platform-head{display:flex;align-items:center;gap:15px}
.platform-icon{
  width:52px;height:52px;border-radius:15px;flex-shrink:0;
  background:var(--brand-soft);color:var(--brand-deep);
  display:flex;align-items:center;justify-content:center;
}
.platform-icon svg{width:26px;height:26px}
.platform-head h3{font-size:18px}
.platform-head .sub{font-size:13px;color:var(--muted);font-weight:600;margin-top:2px}
.platform-meta{display:flex;flex-wrap:wrap;gap:8px;margin:18px 0 4px}
.platform-desc{margin-top:14px;font-size:14.5px;line-height:1.8}
.platform-actions{display:flex;flex-wrap:wrap;gap:12px;margin-top:auto;padding-top:22px}
.detected-flag{
  position:absolute;top:18px;right:18px;
  display:none;align-items:center;gap:6px;
  padding:5px 12px;border-radius:var(--r-pill);
  background:var(--brand-soft-2);color:var(--brand-ink);
  font-size:12px;font-weight:800;
}
.detected-flag::before{content:"";width:6px;height:6px;border-radius:50%;background:var(--brand)}
.platform-card.detected .detected-flag{display:inline-flex}
.detect-hint{font-size:13.5px;color:var(--brand-ink);font-weight:700}

/* ---------- 安装步骤 ---------- */
.steps{display:grid;grid-template-columns:repeat(4,1fr);gap:22px;counter-reset:step}
.step{
  position:relative;padding:26px 24px;border-radius:var(--r-lg);
  background:#FFF;border:1px solid var(--line);box-shadow:var(--shadow-sm);
}
.step-num{
  width:38px;height:38px;border-radius:50%;margin-bottom:16px;
  background:var(--grad);color:#FFF;font-weight:800;font-size:16px;
  display:flex;align-items:center;justify-content:center;
  box-shadow:0 8px 18px rgba(42,171,238,.3);
}
.step h3{font-size:16px;margin-bottom:8px}
.step p{font-size:14.2px;line-height:1.75}

/* ---------- 关于页：时间线 ---------- */
.timeline{position:relative;max-width:760px;margin:0 auto;padding-left:34px}
.timeline::before{
  content:"";position:absolute;left:9px;top:6px;bottom:6px;width:2px;
  background:linear-gradient(180deg,var(--brand),rgba(42,171,238,.15));
}
.timeline-item{position:relative;padding:0 0 34px 22px}
.timeline-item:last-child{padding-bottom:0}
.timeline-item::before{
  content:"";position:absolute;left:-31px;top:6px;
  width:16px;height:16px;border-radius:50%;
  background:#FFF;border:4px solid var(--brand);
  box-shadow:0 0 0 4px var(--brand-soft);
}
.timeline-year{font-size:14px;font-weight:800;color:var(--brand-deep);letter-spacing:.04em}
.timeline-item h3{font-size:16.5px;margin:6px 0 6px}
.timeline-item p{font-size:14.5px;line-height:1.8}

/* ---------- 价值卡片 ---------- */
.value-card{
  padding:30px 28px;border-radius:var(--r-lg);text-align:center;
  background:#FFF;border:1px solid var(--line);box-shadow:var(--shadow-sm);
  transition:transform .2s ease,box-shadow .2s ease;
}
.value-card:hover{transform:translateY(-4px);box-shadow:var(--shadow-md)}
.value-icon{
  width:56px;height:56px;border-radius:50%;margin:0 auto 18px;
  background:var(--brand-soft);color:var(--brand-deep);
  display:flex;align-items:center;justify-content:center;
}
.value-icon svg{width:26px;height:26px}
.value-card h3{font-size:17px;margin-bottom:9px}
.value-card p{font-size:14.4px;line-height:1.75}

/* ---------- CTA 区块 ---------- */
.cta-band{
  position:relative;overflow:hidden;
  border-radius:var(--r-xl);padding:64px 40px;text-align:center;
  background:var(--grad);color:#FFF;
  box-shadow:0 26px 64px rgba(34,158,217,.35);
}
.cta-band::before{
  content:"";position:absolute;inset:0;pointer-events:none;
  background:
    radial-gradient(320px 180px at 12% -10%,rgba(255,255,255,.22),transparent 70%),
    radial-gradient(380px 200px at 92% 120%,rgba(255,255,255,.16),transparent 70%);
}
.cta-band h2{color:#FFF;font-size:clamp(1.6rem,3vw,2.15rem);position:relative}
.cta-band p{color:rgba(255,255,255,.88);max-width:600px;margin:14px auto 0;position:relative;font-size:16px}
.cta-actions{display:flex;justify-content:center;gap:14px;flex-wrap:wrap;margin-top:32px;position:relative}

/* ---------- 页脚 ---------- */
.site-footer{background:var(--bg-soft);border-top:1px solid var(--line);padding:64px 0 0}
.footer-grid{display:grid;grid-template-columns:1.5fr 1fr 1fr 1fr;gap:44px}
.footer-brand p{margin:16px 0 20px;font-size:14.4px;line-height:1.8;max-width:290px}
.social-row{display:flex;gap:10px}
.icon-btn{
  width:38px;height:38px;border-radius:50%;
  background:#FFF;border:1px solid var(--line-strong);color:var(--text);
  display:inline-flex;align-items:center;justify-content:center;
  transition:all .18s ease;
}
.icon-btn svg{width:17px;height:17px}
.icon-btn:hover{border-color:var(--brand);color:var(--brand-deep);transform:translateY(-2px);box-shadow:var(--shadow-sm)}
.footer-title{font-size:14px;font-weight:800;color:var(--ink);letter-spacing:.05em;margin-bottom:18px;text-transform:uppercase}
.footer-links{display:grid;gap:11px}
.footer-links a{font-size:14.4px;color:var(--text);font-weight:600;transition:color .18s ease}
.footer-links a:hover{color:var(--brand-deep)}
.footer-bottom{
  margin-top:52px;padding:22px 0;
  border-top:1px solid var(--line);
  display:flex;align-items:center;justify-content:space-between;gap:18px;flex-wrap:wrap;
  font-size:13.5px;color:var(--muted);
}
.footer-legal{display:flex;gap:22px}
.footer-legal a{color:var(--muted);font-weight:600;transition:color .18s ease}
.footer-legal a:hover{color:var(--brand-deep)}

/* ---------- 入场动效 ---------- */
.reveal{opacity:0;transform:translateY(22px);transition:opacity .6s ease var(--d,0s),transform .6s ease var(--d,0s)}
.reveal.visible{opacity:1;transform:none}
@media(prefers-reduced-motion:reduce){
  html{scroll-behavior:auto}
  .reveal{opacity:1;transform:none;transition:none}
}

/* ---------- 说明框 ---------- */
.note-box{
  display:flex;gap:13px;align-items:flex-start;
  padding:18px 20px;border-radius:var(--r-md);
  background:var(--brand-soft);border:1px solid rgba(42,171,238,.25);
  font-size:14.2px;line-height:1.75;
}
.note-box svg{width:19px;height:19px;color:var(--brand-deep);flex-shrink:0;margin-top:2px}

/* ---------- 响应式 ---------- */
@media(max-width:1024px){
  .cols-4{grid-template-columns:repeat(2,1fr)}
  .cols-3{grid-template-columns:repeat(2,1fr)}
  .steps{grid-template-columns:repeat(2,1fr)}
  .footer-grid{grid-template-columns:1fr 1fr;gap:36px}
  .split{gap:38px;padding:36px 0}
}
@media(max-width:900px){
  .section{padding:66px 0}
  .split{grid-template-columns:1fr}
  .split--flip .split-copy{order:1}
  .split--flip .split-media{order:2}
  .featured-post{grid-template-columns:1fr}
  .featured-post .post-cover{min-height:190px}
  .platform-grid{grid-template-columns:1fr}
  .hero{padding-top:calc(var(--header-h) + 44px)}
}
@media(max-width:640px){
  .lang-btn{padding:4px 10px;font-size:12.5px}
  .stats-grid{grid-template-columns:repeat(2,1fr);gap:28px 16px}
  .cols-2,.cols-3,.cols-4{grid-template-columns:1fr}
  .steps{grid-template-columns:1fr}
  .footer-grid{grid-template-columns:1fr;gap:30px}
  .cta-band{padding:48px 24px}
  .page-hero{padding-top:calc(var(--header-h) + 40px)}
  .accordion-content{padding-left:22px}
  .accordion-head{padding:16px 18px;font-size:15px}
  .platform-actions .btn{flex:1;justify-content:center}
}