/* ============================================================
   site-chrome.css —— 51-ai.cn 全站统一导航与底部（与主页对齐）
   命名空间：.w51-*   避免与 home/price 模板的 .nav/.brand/.foot 冲突
   颜色：与主页（index.html）一致；使用真实 logo 图（assets/images/logo-51.png）

   ⚠️ 结构由 assets/js/site-chrome.js **单点渲染**（Header/Footer 唯一真源）。
      页面只留 <header class="w51-nav" data-w51-chrome="header"> 空壳。
      改导航/页脚只改 site-chrome.js + 本文件，全站同步。
   ============================================================ */

/* 设计 token（与主页一致；声明在 :root 与 [data-theme=dark]） */
:root {
  --w51-ink: #1d1d1f;
  --w51-ink-2: #4b5563;
  --w51-ink-3: #8a8f98;
  --w51-paper: #ffffff;
  --w51-paper-2: #f7f7f8;
  --w51-line: #e6e7ea;
  --w51-line-strong: #c9cbd1;
  --w51-shadow: 0 10px 32px rgba(16, 18, 27, .06);
  --w51-accent: #4f85ff;
  --w51-accent-ink: #2f6dff;
  --w51-accent-wash: #eef4ff;
  --w51-brand: #f47559;
  --w51-brand-deep: #c44131;
  --w51-cta: #1d1d1f;
  --w51-cta-hover: #000000;
  --w51-nav-bg: rgba(255, 255, 255, .82);
  --w51-foot-bg: #ffffff;
  --w51-ok: #059669;
  --w51-ok-wash: #ecfdf5;
  --w51-danger: #dc2626;
  --w51-radius: 16px;
  --w51-radius-s: 10px;
  --w51-font: -apple-system, BlinkMacSystemFont, "SF Pro SC", "SF Pro Text",
              "PingFang SC", "Helvetica Neue", "Microsoft YaHei", sans-serif;
}
[data-theme="dark"] {
  --w51-ink: #eef4ff;
  --w51-ink-2: #a8b5d8;
  --w51-ink-3: #7c8bad;
  --w51-paper: #0d1530;
  --w51-paper-2: #142246;
  --w51-line: rgba(167, 197, 255, .14);
  --w51-line-strong: rgba(167, 197, 255, .32);
  --w51-shadow: 0 10px 32px rgba(4, 8, 20, .32);
  --w51-accent: #4f85ff;
  --w51-accent-ink: #7aa2ff;
  --w51-accent-wash: rgba(79, 133, 255, .16);
  --w51-brand: #f47559;
  --w51-brand-deep: #c44131;
  --w51-cta: #f47559;
  --w51-cta-hover: #c44131;
  --w51-nav-bg: rgba(13, 21, 48, .82);
  --w51-foot-bg: #0d1530;
  --w51-ok: #38c08a;
  --w51-ok-wash: rgba(56, 192, 138, .15);
  --w51-danger: #ff8a7a;
}

/* ====================== 顶部导航 ====================== */
/* 一级导航定稿（7 项）：WorkFriend ｜ AI产品 ｜ AI算力 ｜ 模型与API ｜ 解决方案 ｜ 关于五一 ｜ 联系商务
   前 6 项带下拉，第 7 项「联系商务」是右侧 CTA（企业微信）。 */

/* FOUC 防护：Header 由 </body> 前的 site-chrome.js 同步注入。
   注入前先占住 64px 高度，避免导航栏「突然冒出来」把整页往下推（布局跳动）。 */
.w51-nav[data-w51-chrome="header"]:empty { min-height: 64px; }

.w51-nav {
  position: sticky; top: 0; z-index: 100;
  background: var(--w51-nav-bg);
  -webkit-backdrop-filter: saturate(180%) blur(14px);
          backdrop-filter: saturate(180%) blur(14px);
  border-bottom: 1px solid var(--w51-line);
  font-family: var(--w51-font);
  color: var(--w51-ink);
}
.w51-nav-in {
  max-width: 1120px; margin: 0 auto; padding: 0 22px;
  display: flex; align-items: center; height: 64px; gap: 22px;
  position: relative;
}
.w51-brand {
  display: inline-flex; align-items: center; gap: 10px;
  font-weight: 700; font-size: 17px; letter-spacing: -0.01em;
  color: var(--w51-ink); text-decoration: none;
  transition: opacity .15s ease;
  flex: none;
}
.w51-brand:hover { opacity: .8; }
.w51-brand img {
  display: block; height: 29px; width: auto; border-radius: 6px;
  /* 真实 logo 是白底（51tech + 五一科技!），深色主题下保持原样显示，
     形成"白色字标 on 暗色 nav"的常见品牌呈现，避免反色滤镜破坏品牌色。 */
}

.w51-links {
  display: flex; align-items: center; gap: 1px; margin-left: auto;
  font-size: 14px; color: var(--w51-ink-2);
  list-style: none; padding: 0;
}
.w51-links .w51-item { position: relative; display: flex; align-items: center; }
.w51-links .w51-item-link {
  position: relative;
  display: inline-flex; align-items: center; gap: 5px;
  padding: 9px 11px; border-radius: 9px;
  color: inherit; text-decoration: none; font-size: 14px; white-space: nowrap;
  transition: color .15s ease, background .15s ease;
}
.w51-links .w51-item-link:hover { color: var(--w51-ink); background: var(--w51-paper-2); }
.w51-links .w51-item.w51-active > .w51-item-link { color: var(--w51-ink); font-weight: 600; }
.w51-links .w51-item.w51-active > .w51-item-link::after {
  content: ""; position: absolute; left: 11px; right: 11px; bottom: 2px;
  height: 2px; border-radius: 2px;
  background: linear-gradient(90deg, var(--w51-brand), var(--w51-brand-deep));
}
.w51-caret { width: 11px; height: 11px; flex: none; opacity: .55; transition: transform .2s ease; }
.w51-item:hover > .w51-item-link .w51-caret,
.w51-item.is-open > .w51-item-link .w51-caret { transform: rotate(180deg); opacity: .85; }

/* 移动端专用的二级菜单展开按钮（桌面端隐藏） */
.w51-item-more { display: none; }

/* 二级菜单：桌面 absolute 浮层，移动端手风琴 */
.w51-drop { position: absolute; }
@media (min-width: 1025px) {
  .w51-drop {
    top: calc(100% + 8px); left: 0; min-width: 238px;
    background: var(--w51-paper);
    border: 1px solid var(--w51-line);
    border-radius: 14px;
    box-shadow: var(--w51-shadow);
    padding: 8px;
    z-index: 120;
    opacity: 0; visibility: hidden; transform: translateY(6px);
    transition: opacity .16s ease, transform .16s ease, visibility .16s ease;
  }
  .w51-item:hover > .w51-drop,
  .w51-item:focus-within > .w51-drop,
  .w51-item.is-open > .w51-drop { opacity: 1; visibility: visible; transform: none; }
  /* 悬浮桥：鼠标从一级菜单移向浮层途中不误收 */
  .w51-item.w51-has-drop::after {
    content: ""; position: absolute; left: 0; right: 0; top: 100%; height: 10px;
  }
}
@media (max-width: 1024px) {
  .w51-drop { display: none; }
  .w51-item.is-open > .w51-drop { display: block; }
}

.w51-drop-sep {
  margin: 7px 4px 3px; padding: 7px 8px 0;
  border-top: 1px solid var(--w51-line);
  font-size: 11.5px; color: var(--w51-ink-3); letter-spacing: .02em;
}
.w51-drop-link {
  display: block; padding: 9px 12px; border-radius: 9px;
  color: var(--w51-ink-2); text-decoration: none;
  font-size: 13.5px; line-height: 1.45;
  transition: background .15s ease, color .15s ease;
}
.w51-drop-link:hover { background: var(--w51-paper-2); color: var(--w51-ink); }
.w51-drop-top { display: flex; align-items: center; gap: 6px; }
.w51-drop-name { font-size: 14px; font-weight: 600; color: var(--w51-ink); }
.w51-drop-desc { display: block; margin-top: 3px; font-size: 12.5px; color: var(--w51-ink-3); }
.w51-drop-ext { margin-left: auto; font-size: 11.5px; color: var(--w51-ink-3); white-space: nowrap; }
.w51-drop-arrow { font-size: 11px; color: var(--w51-ink-3); }

/* 「自研 / 合作」标签 —— 必须让人一眼分清哪些是我们自己的产品 */
.w51-tag {
  font-style: normal; flex: none;
  font-size: 11px; font-weight: 600; line-height: 1;
  padding: 3px 6px; border-radius: 5px;
}
.w51-tag-self { color: var(--w51-accent-ink); background: var(--w51-accent-wash); }
.w51-tag-partner {
  color: var(--w51-ink-2); background: var(--w51-paper-2);
  border: 1px solid var(--w51-line);
}

/* 「联系商务」—— Header 右侧突出显示的商务入口（统一企业微信） */
.w51-cta {
  margin-left: 2px; padding: 9px 18px; border-radius: 999px;
  background: var(--w51-cta); color: #fff;
  font-size: 13.5px; font-weight: 600; text-decoration: none; white-space: nowrap;
  flex: none;
  transition: transform .15s ease, background .2s ease, box-shadow .2s ease;
  box-shadow: 0 2px 8px rgba(29, 29, 31, .12);
}
.w51-cta:hover { transform: translateY(-1px); background: var(--w51-cta-hover); }

.w51-nav-toggle {
  display: none;
  width: 40px; height: 40px; border: 0; background: transparent;
  border-radius: 10px; color: var(--w51-ink); cursor: pointer;
  align-items: center; justify-content: center; flex: none;
}
.w51-nav-toggle:hover { background: var(--w51-paper-2); }
.w51-nav-toggle svg { width: 22px; height: 22px; }

/* ---------------------- 移动端导航（≤1024px） ---------------------- */
@media (max-width: 1024px) {
  .w51-nav-in { gap: 12px; }
  .w51-links { display: none; }
  .w51-nav-toggle { display: inline-flex; }
  .w51-cta { padding: 8px 14px; font-size: 13px; }

  .w51-mobile-open .w51-links {
    display: flex; flex-direction: column; align-items: stretch; gap: 2px;
    position: absolute; top: 64px; left: 0; right: 0;
    max-height: calc(100vh - 64px); overflow-y: auto;
    -webkit-overflow-scrolling: touch;
    background: var(--w51-paper);
    border-bottom: 1px solid var(--w51-line);
    padding: 10px 16px calc(18px + env(safe-area-inset-bottom, 0px)); margin: 0;
    box-shadow: var(--w51-shadow);
  }
  .w51-mobile-open .w51-links .w51-item { display: block; }
  .w51-mobile-open .w51-links .w51-item-link {
    display: flex; justify-content: flex-start;
    padding: 13px 56px 13px 10px; border-radius: 10px; font-size: 15px;
  }
  .w51-mobile-open .w51-links .w51-item-link .w51-caret { display: none; }
  .w51-mobile-open .w51-links .w51-item.w51-active > .w51-item-link::after { display: none; }

  /* 展开按钮：≥44px 点击区，靠右与标题同排 */
  .w51-item-more {
    display: inline-flex; align-items: center; justify-content: center;
    position: absolute; right: 2px; top: 0;
    width: 46px; height: 46px; padding: 0;
    border: 0; background: transparent; cursor: pointer;
    border-radius: 10px; color: var(--w51-ink-2);
  }
  .w51-item-more:hover { background: var(--w51-paper-2); }
  .w51-item-more .w51-caret { width: 14px; height: 14px; opacity: .7; }
  .w51-item.is-open > .w51-item-more .w51-caret { transform: rotate(180deg); }

  /* 手风琴里的二级菜单：不再浮层，改为缩进列表 */
  .w51-mobile-open .w51-drop {
    position: static; padding: 2px 0 8px 10px; margin: 0 0 4px 10px;
    min-width: 0; background: transparent; border: 0; border-radius: 0;
    border-left: 2px solid var(--w51-line); box-shadow: none;
  }
  .w51-mobile-open .w51-drop-link { padding: 11px 10px; font-size: 14px; }
}

/* ====================== 底部（五栏 + 商务 + 版权/备案） ====================== */
.w51-foot {
  font-family: var(--w51-font);
  background: var(--w51-foot-bg);
  color: var(--w51-ink);
  border-top: 1px solid var(--w51-line);
  padding: 48px 0 40px;
}
.w51-foot-in { max-width: 1120px; margin: 0 auto; padding: 0 24px; }

.w51-foot-main {
  display: grid; grid-template-columns: minmax(0, 1.05fr) minmax(0, 2.05fr);
  gap: 48px;
}
.w51-foot-brand .w51-brand img { height: 30px; }
.w51-foot-slogan {
  margin: 16px 0 6px; font-size: 18px; font-weight: 700;
  letter-spacing: -0.01em; color: var(--w51-ink);
}
.w51-foot-scope { margin: 0 0 12px; font-size: 13px; color: var(--w51-accent-ink); }
.w51-foot-intro {
  margin: 0; max-width: 370px;
  font-size: 13px; line-height: 1.75; color: var(--w51-ink-3);
}

.w51-foot-cols { display: grid; grid-template-columns: repeat(4, minmax(0, 1fr)); gap: 28px; }
.w51-foot-col h4 {
  margin: 0 0 13px; font-size: 13.5px; font-weight: 700; color: var(--w51-ink);
}
.w51-foot-col ul { list-style: none; margin: 0; padding: 0; display: flex; flex-direction: column; gap: 10px; }
.w51-foot-col a {
  font-size: 13px; color: var(--w51-ink-2);
  text-decoration: none; transition: color .15s ease;
}
.w51-foot-col a:hover { color: var(--w51-ink); }

.w51-foot-biz {
  margin-top: 36px; padding: 20px 24px;
  border: 1px solid var(--w51-line); border-radius: 16px;
  background: var(--w51-paper-2);
  display: flex; align-items: center; justify-content: space-between;
  gap: 20px; flex-wrap: wrap;
}
.w51-foot-biz-text { display: flex; flex-direction: column; gap: 4px; }
.w51-foot-biz-text strong { font-size: 15.5px; font-weight: 700; color: var(--w51-ink); }
.w51-foot-biz-text span { font-size: 13px; color: var(--w51-ink-3); }

.w51-foot-copy {
  margin-top: 26px; padding-top: 20px;
  border-top: 1px solid var(--w51-line);
  font-size: 12.5px; color: var(--w51-ink-3); line-height: 1.9;
}
.w51-foot-copy-line { display: flex; flex-wrap: wrap; align-items: center; }
.w51-foot-policy { margin-top: 6px; }
.w51-foot-sep { margin: 0 7px; opacity: .45; }
.w51-foot-copy a { color: inherit; text-decoration: none; }
.w51-foot-copy a:hover { color: var(--w51-ink); text-decoration: underline; text-underline-offset: 3px; }

@media (max-width: 900px) {
  .w51-foot { padding: 36px 0 32px; }
  .w51-foot-main { grid-template-columns: 1fr; gap: 32px; }
  .w51-foot-cols { grid-template-columns: 1fr 1fr; gap: 24px; }
  .w51-foot-intro { max-width: none; }
}
@media (max-width: 520px) {
  .w51-foot-cols { grid-template-columns: 1fr; gap: 20px; }
  .w51-foot-biz { flex-direction: column; align-items: stretch; }
  .w51-foot-biz .w51-btn { width: 100%; }
}

/* ====================== lead 二维码面板（企业咨询） ====================== */
.w51-lead {
  font-family: var(--w51-font);
}
.w51-lead .w51-lead-card {
  max-width: 920px; margin: 36px auto 0;
  background: var(--w51-paper);
  border: 1px solid var(--w51-line);
  border-radius: 20px;
  box-shadow: var(--w51-shadow);
  padding: 40px 36px;
  display: grid; grid-template-columns: 1.05fr .95fr; gap: 36px;
  align-items: center;
}
[data-theme="dark"] .w51-lead .w51-lead-card { background: var(--w51-paper-2); }
.w51-lead-text h3 {
  font-size: 22px; font-weight: 700; letter-spacing: -0.01em;
  color: var(--w51-ink); margin-bottom: 8px;
}
.w51-lead-text p {
  color: var(--w51-ink-2); font-size: 15px; line-height: 1.7;
  margin: 0 0 18px;
}
.w51-lead-actions { display: flex; gap: 10px; flex-wrap: wrap; }
.w51-btn {
  display: inline-flex; align-items: center; justify-content: center; gap: 8px;
  padding: 12px 22px; border-radius: 999px;
  font-size: 14.5px; font-weight: 600; line-height: 1.2;
  text-decoration: none; border: 1px solid transparent; cursor: pointer;
  font-family: inherit; transition: transform .15s ease, background .2s ease, border-color .2s ease;
}
.w51-btn-dark { background: var(--w51-cta); color: #fff; }
.w51-btn-dark:hover { background: var(--w51-cta-hover); transform: translateY(-1px); }
.w51-btn-ghost { background: transparent; color: var(--w51-ink); border-color: var(--w51-line); }
.w51-btn-ghost:hover { border-color: var(--w51-ink-3); background: var(--w51-paper-2); }
.w51-btn-link {
  background: transparent; color: var(--w51-ink-2); border: 0;
  padding: 12px 4px; text-decoration: none;
}
.w51-btn-link:hover { color: var(--w51-ink); }

.w51-lead-qr {
  display: flex; flex-direction: column; align-items: center;
  padding: 24px 16px; border-radius: 16px;
  background: var(--w51-paper-2);
}
[data-theme="dark"] .w51-lead-qr { background: rgba(255,255,255,.04); }
.w51-lead-qr-frame {
  position: relative;
  /* 客服卡片 assets/images/kefu.png 是 700×908 竖版，容器按同比例避免上下留白 */
  width: 200px; height: 260px; border-radius: 14px;
  background: #fff; padding: 10px;
  box-shadow: 0 6px 18px rgba(0,0,0,.06);
  transition: transform .25s cubic-bezier(.2,.7,.3,1);
}
.w51-lead-qr-frame:hover { transform: translateY(-2px) scale(1.01); }
.w51-lead-qr-frame img {
  display: block; width: 100%; height: 100%;
  object-fit: contain; border-radius: 6px;
}
.w51-lead-qr-cap {
  margin-top: 14px; text-align: center; font-size: 13px;
  color: var(--w51-ink-2); line-height: 1.6;
}
.w51-lead-qr-cap b { color: var(--w51-ink); font-weight: 600; }
.w51-lead-qr-cap small { display: block; color: var(--w51-ink-3); margin-top: 2px; }

@media (max-width: 720px) {
  .w51-lead .w51-lead-card { grid-template-columns: 1fr; padding: 28px 22px; }
  .w51-lead-qr-frame { width: 172px; height: 224px; }
}

/* lead 区域下的"或填写需求表单"折叠面板（保留原表单作为次要入口） */
.w51-lead-form-details {
  grid-column: 1 / -1;
  margin-top: 28px;
  border-top: 1px dashed var(--w51-line);
  padding-top: 18px;
}
.w51-lead-form-details > summary {
  list-style: none;
  cursor: pointer;
  font-size: 14px;
  color: var(--w51-ink-2);
  display: inline-flex; align-items: center; gap: 6px;
  padding: 4px 0;
  user-select: none;
  transition: color .15s ease;
}
.w51-lead-form-details > summary::-webkit-details-marker { display: none; }
.w51-lead-form-details > summary::before {
  content: "+"; width: 16px; height: 16px;
  display: inline-flex; align-items: center; justify-content: center;
  border: 1px solid var(--w51-line-strong); border-radius: 4px;
  font-size: 12px; color: var(--w51-ink-2);
  transition: transform .2s ease, background .2s ease;
}
.w51-lead-form-details[open] > summary::before { content: "−"; background: var(--w51-paper-2); }
.w51-lead-form-details > summary:hover { color: var(--w51-ink); }
.w51-lead-form-details[open] > summary { margin-bottom: 16px; }

/* 在折叠面板内恢复原表单的字段排布（与主页 lead 区一致） */
.w51-lead-form-details .lead-q { font-size: 16px; font-weight: 700; color: var(--w51-ink); }
.w51-lead-form-details .interests { display: flex; flex-wrap: wrap; gap: 10px; margin: 14px 0 22px; }
.w51-lead-form-details .ichip {
  display: inline-flex; align-items: center;
  padding: 8px 16px; border-radius: 999px;
  border: 1px solid var(--w51-line);
  font-size: 14px; color: var(--w51-ink-2);
  cursor: pointer; background: var(--w51-paper);
  transition: all .15s ease;
}
.w51-lead-form-details .ichip:hover { border-color: var(--w51-ink-3); color: var(--w51-ink); }
.w51-lead-form-details .ichip.on { background: var(--w51-accent-wash); border-color: var(--w51-accent); color: var(--w51-accent-ink); font-weight: 600; }
.w51-lead-form-details .frow { display: grid; grid-template-columns: 1fr 1fr; gap: 16px; margin-bottom: 16px; }
@media (max-width: 640px) { .w51-lead-form-details .frow { grid-template-columns: 1fr; } }
.w51-lead-form-details .field label { display: block; font-size: 13px; color: var(--w51-ink-2); margin-bottom: 6px; }
.w51-lead-form-details .field input {
  width: 100%; padding: 12px 14px;
  border: 1px solid var(--w51-line); border-radius: 10px;
  background: var(--w51-paper); color: var(--w51-ink);
  font: inherit; outline: none;
  transition: border-color .15s ease, box-shadow .15s ease;
}
.w51-lead-form-details .field input:focus { border-color: var(--w51-accent); box-shadow: 0 0 0 3px var(--w51-accent-wash); }
.w51-lead-form-details .lead-submit { width: 100%; margin-top: 8px; }
.w51-lead-form-details .lead-err { display: none; margin-top: 12px; font-size: 14px; color: var(--w51-danger); }
.w51-lead-form-details .lead-ok { display: none; margin-top: 18px; padding: 24px; border: 1px solid var(--w51-line); border-radius: 14px; background: var(--w51-ok-wash); text-align: center; }
.w51-lead-form-details .lead-ok .tick {
  width: 40px; height: 40px; border-radius: 50%;
  background: var(--w51-ok); color: #fff;
  display: flex; align-items: center; justify-content: center; margin: 0 auto 12px;
}
.w51-lead-form-details .lead-ok h3 { font-size: 18px; color: var(--w51-ink); }
.w51-lead-form-details .lead-ok p { color: var(--w51-ink-2); font-size: 14px; margin-top: 6px; }

/* ====================== Apple 风丝滑入场 ====================== */
.w51-reveal {
  opacity: 0; transform: translateY(22px);
  transition: opacity .65s cubic-bezier(.2,.7,.3,1), transform .65s cubic-bezier(.2,.7,.3,1);
  will-change: opacity, transform;
}
.w51-reveal.w51-in { opacity: 1; transform: none; }
.w51-reveal[data-delay="1"] { transition-delay: .08s; }
.w51-reveal[data-delay="2"] { transition-delay: .16s; }
.w51-reveal[data-delay="3"] { transition-delay: .24s; }
.w51-reveal[data-delay="4"] { transition-delay: .32s; }
@media (prefers-reduced-motion: reduce) {
  .w51-reveal { opacity: 1; transform: none; transition: none; }
}

/* 通用丝滑：被 hover / focus 抬升的小元件（给 price/home 卡片复用） */
.w51-lift {
  transition: transform .25s cubic-bezier(.2,.7,.3,1), box-shadow .25s ease, border-color .2s ease;
  will-change: transform;
}
.w51-lift:hover { transform: translateY(-3px); }

/* 滚动丝滑（仅在用户未设置 prefers-reduced-motion 时生效） */
html { scroll-behavior: smooth; }
@media (prefers-reduced-motion: reduce) { html { scroll-behavior: auto; } }