/* 小黑大使：与官网其他页面统一的浅色版式（官网页头 + 白底绿色强调 + 统一页脚）。主页、子页面与报名页共用。 */
:root{color-scheme:light;--amb-ink:#1f2622;--amb-muted:#56615a;--amb-subtle:#6b756e;--amb-green:#16723c;--amb-green-bright:#15803d;--amb-green-deep:#123b24;--amb-line:#e3e9e4;--amb-soft:#f4f7f4;--amb-tint:#edf5ef;--amb-font:"Noto Sans SC Variable","PingFang SC","Microsoft YaHei","Segoe UI",system-ui,sans-serif}
*{box-sizing:border-box}
html{scroll-behavior:smooth;scroll-padding-top:96px}
body{margin:0;color:var(--amb-ink);background:#fff;font-family:var(--amb-font);font-size:16px;line-height:1.75;-webkit-font-smoothing:antialiased;font-synthesis:none}
h1,h2,h3,p{margin:0}
a{color:inherit;text-decoration:none}
img{display:block;max-width:100%}
button,input,textarea{font:inherit}
a,button,summary{touch-action:manipulation;-webkit-tap-highlight-color:transparent}
a:focus-visible,button:focus-visible,summary:focus-visible{outline:2px solid var(--amb-green);outline-offset:4px}
[hidden]{display:none!important}
.skip-link{position:fixed;top:-90px;left:15px;z-index:150;background:var(--amb-green);color:#fff;padding:12px 18px;border-radius:8px}
.skip-link:focus{top:12px}
.amb-wrap{width:min(1120px,calc(100% - 48px));margin-inline:auto}
.amb-icon{display:block;width:22px;height:22px}

/* 官网页头里的汉堡按钮图标（其余页头样式来自 official-header.css）。 */
.site-header .site-menu-toggle svg{width:22px;height:22px}

/* 通用按钮：报名页的提交按钮也复用 .signup-button。 */
.signup-button{display:inline-flex;align-items:center;justify-content:center;gap:9px;min-height:52px;padding:0 30px;border:0;border-radius:999px;background:var(--amb-green);color:#fff;font-size:16px;font-weight:600;cursor:pointer;transition:background .2s,transform .2s}
.signup-button:hover{background:#0f5b2f;transform:translateY(-1px)}
.signup-button svg{width:19px;height:19px}


/* 主页：首屏 */
.amb-hero{padding:64px 0 72px;background:linear-gradient(180deg,#f2f8f3 0%,#fff 100%)}
.amb-hero-grid{display:grid;grid-template-columns:minmax(0,1fr) minmax(0,360px);gap:48px;align-items:center}
.amb-kicker{font-size:15px;font-weight:600;letter-spacing:.2em;color:var(--amb-green)}
.amb-hero h1{margin-top:14px;font-size:64px;line-height:1.18;font-weight:800;letter-spacing:.01em}
.amb-hero h1 span{color:var(--amb-green-bright)}
.amb-slogan{margin-top:22px;font-size:20px;color:var(--amb-muted)}
.amb-stamp{display:inline-block;margin-top:24px;padding:5px 14px;border:1px solid #b9d6c2;border-radius:999px;background:var(--amb-tint);color:var(--amb-green);font-size:14px;font-weight:600;letter-spacing:.12em}
.amb-caption{margin-top:30px;font-size:12px;letter-spacing:.24em;color:#8a948d}
.amb-hero-art{position:relative;width:100%;aspect-ratio:1;max-width:360px;justify-self:end}
.amb-hero-art:before{content:"";position:absolute;inset:8% 6% 4%;border-radius:50%;background:radial-gradient(circle at 50% 45%,#e1f0e5 0%,#f2f8f3 62%,transparent 72%)}
.amb-hero-art span{position:absolute;inset:0;background:url("https://xiaoheiribao.tos-cn-shanghai.volces.com/website/v8/assets/a1.png") 100% 0/300% 400% no-repeat;mix-blend-mode:multiply}

/* 主页：介绍 */
.amb-intro{padding:72px 0 80px;text-align:center}
.amb-intro h2,.amb-section-head h2{font-size:36px;line-height:1.35;font-weight:700}
.amb-intro p{max-width:640px;margin:20px auto 0;font-size:17px;line-height:1.9;color:var(--amb-muted)}
.amb-intro .amb-invitation{margin-top:12px;color:var(--amb-ink)}
.amb-intro .signup-button{margin-top:34px}
.amb-hint{margin-top:14px!important;font-size:14px!important;color:var(--amb-subtle)!important}
.amb-intro h2,.amb-section-head h2,.community-intro h1,.community-notice h2{text-wrap:balance}

/* 主页：分区 */
.amb-section{padding:80px 0;border-top:1px solid var(--amb-line)}
.amb-section-soft{background:var(--amb-soft);border-top:0}
.amb-section-head{text-align:center;margin-bottom:40px}
.amb-section-head .amb-kicker{letter-spacing:.08em;margin-bottom:10px}
.amb-section-head>p:not(.amb-kicker){margin-top:12px;font-size:17px;color:var(--amb-muted)}
.amb-grid{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:20px}
.amb-card{padding:30px 28px;border:1px solid var(--amb-line);border-radius:14px;background:#fff}
.amb-card-icon{display:grid;place-items:center;width:46px;height:46px;border-radius:12px;background:var(--amb-tint);color:var(--amb-green)}
.amb-card h3{margin-top:20px;font-size:21px;font-weight:700}
.amb-card p{margin-top:8px;font-size:16px;line-height:1.8;color:var(--amb-muted)}
.amb-callout{margin-top:24px;padding:20px 24px;border-radius:14px;background:var(--amb-green-deep);color:#d6eadc;font-size:17px;text-align:center}
.amb-callout strong{color:#fff;font-weight:600}
a.amb-card{display:flex;flex-direction:column;transition:border-color .2s,transform .2s}
a.amb-card:hover{border-color:#a5baac;transform:translateY(-2px)}
.amb-card-more{display:inline-flex;align-items:center;gap:6px;margin-top:auto;padding-top:18px;font-size:15px;font-weight:600;color:var(--amb-green)}
.amb-card-more svg{width:17px;height:17px;transition:transform .2s}
a.amb-card:hover .amb-card-more svg{transform:translateX(3px)}
.amb-resource{display:flex;flex-direction:column;align-items:center;text-align:center;padding:28px 24px 26px;border:1px solid var(--amb-line);border-radius:14px;background:#fff;transition:border-color .2s,transform .2s}
.amb-resource:hover{border-color:#a5baac;transform:translateY(-2px)}
.amb-resource img{width:168px;height:168px;border-radius:10px;border:1px solid var(--amb-line);padding:8px;background:#fff}
.amb-resource h3{margin-top:18px;font-size:19px;font-weight:700}
.amb-resource p{margin-top:4px;font-size:15px;color:var(--amb-muted)}

/* 子页面（官方活动 / 大使伙伴 / 大使荣誉）：沿用原有内容结构。 */
.amb-community{padding:64px 0 88px;background:linear-gradient(180deg,#f2f8f3 0%,#fff 320px)}
.amb-community .community-content{width:min(820px,calc(100% - 48px));margin:0 auto}
.community-intro{text-align:center}
.community-icon{display:inline-grid;place-items:center;width:64px;height:64px;border-radius:18px;background:#fff;border:1px solid var(--amb-line);color:var(--amb-green)}
.community-icon svg{width:30px;height:30px}
.community-intro .section-kicker{margin-top:20px;font-size:15px;font-weight:600;letter-spacing:.08em;color:var(--amb-green)}
.community-intro h1{margin-top:10px;font-size:44px;line-height:1.3;font-weight:800}
.community-intro>p:last-child{margin-top:16px;font-size:17px;line-height:1.9;color:var(--amb-muted)}
.community-notice{margin-top:44px;padding:32px 32px 30px;border-radius:16px;background:var(--amb-green-deep);color:#d6eadc;text-align:center}
.community-status{display:inline-block;padding:4px 12px;border-radius:999px;background:#ffffff1f;color:#bfe6cb;font-size:14px;font-weight:600;letter-spacing:.06em}
.community-notice h2{margin-top:14px;font-size:26px;line-height:1.4;font-weight:700;color:#fff}
.community-notice p{margin-top:10px;font-size:16px;line-height:1.85}
.community-list{margin-top:28px;display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:16px}
.community-list article{padding:24px 22px;border:1px solid var(--amb-line);border-radius:14px;background:#fff}
.community-list h2{font-size:19px;font-weight:700}
.community-list p{margin-top:8px;font-size:15px;line-height:1.8;color:var(--amb-muted)}
.community-note{margin-top:28px;text-align:center;font-size:15px;color:var(--amb-subtle)}

/* 统一页脚 */
.amb-footer{padding:44px 0 36px;border-top:1px solid var(--amb-line);background:#fafbfa}
.amb-footer-top{display:flex;flex-wrap:wrap;align-items:center;justify-content:space-between;gap:24px}
.amb-footer-brand{display:flex;align-items:center;gap:12px}
.amb-footer-brand img{width:34px;height:40px;object-fit:contain}
.amb-footer-brand strong{display:block;font-size:17px;font-weight:700;line-height:1.4}
.amb-footer-brand span{display:block;font-size:14px;color:var(--amb-subtle)}
.amb-footer-links{display:flex;flex-wrap:wrap;gap:8px 26px;font-size:15px;color:var(--amb-muted)}
.amb-footer-links a:hover{color:var(--amb-green)}
.amb-footer-legal{margin-top:28px;padding-top:20px;border-top:1px solid var(--amb-line);display:flex;flex-wrap:wrap;justify-content:space-between;gap:8px 20px;font-size:13px;color:#7d877f}
.amb-footer-legal a:hover{color:var(--amb-green)}

@media(max-width:900px){
  .amb-hero-grid{grid-template-columns:1fr;gap:12px}
  .amb-hero-art{order:-1;max-width:300px;justify-self:center}
  .amb-hero-copy{text-align:center}
  .amb-grid,.community-list{grid-template-columns:1fr}
  .amb-grid-resources{grid-template-columns:repeat(3,minmax(0,1fr))}
}
@media(max-width:640px){
  .amb-wrap,.amb-community .community-content{width:calc(100% - 36px)}
  .amb-community{padding-top:40px}
  /* 原稿里为宽屏排的强制换行，窄屏下让文字自然折行。 */
  .amb-intro p br,.amb-card p br,.community-intro p br{display:none}
  .amb-hero{padding:36px 0 52px}
  .amb-hero h1{font-size:46px}
  .amb-slogan{font-size:17px;margin-top:16px}
  .amb-intro{padding:52px 0 60px}
  .amb-intro h2,.amb-section-head h2{font-size:28px}
  .amb-intro p,.amb-section-head>p:not(.amb-kicker){font-size:16px}
  .amb-section{padding:56px 0}
  .amb-section-head{margin-bottom:28px}
  .amb-card{padding:24px 22px}
  .amb-callout{font-size:16px;padding:18px}
  .amb-grid-resources{grid-template-columns:1fr}
  .amb-resource{flex-direction:row;text-align:left;gap:16px;padding:16px}
  .amb-resource img{width:96px;height:96px;padding:4px;flex:none}
  .amb-resource h3{margin-top:0;font-size:17px}
  .community-intro h1{font-size:34px}
  .community-notice{padding:26px 20px}
  .community-notice h2{font-size:22px}
  .amb-footer-top{flex-direction:column;align-items:flex-start}
}
@media(prefers-reduced-motion:reduce){
  html{scroll-behavior:auto}
  .signup-button,a.amb-card,.amb-resource,.amb-card-more svg{transition:none}
}