/* 中文用途：R5 浅色技术顾问个人品牌；颜色、字体均集中维护，不继承旧版宋体主题。 */
:root {
  --bg: #f5f7f1;
  --surface: #ffffff;
  --surface-soft: #eaf0e6;
  --lime: #d8ef73;
  --fg: #156b57;
  --fg-2: #3e6659;
  --muted: #3e6659;
  --border: #c6d9ce;
  --accent: #c95b32;
  --font-display: "PingFang SC", "Microsoft YaHei", -apple-system, system-ui, sans-serif;
  --font-body: "PingFang SC", "Microsoft YaHei", -apple-system, system-ui, sans-serif;
  --font-latin: "Helvetica Neue", Helvetica, Arial, sans-serif;
  --container-max: 1180px;
  --motion-fast: 160ms;
}

/* 基础语义与可访问性：不裁切横向内容，所有布局以自然换行适配。 */
* { box-sizing: border-box; }
html { scroll-behavior: smooth; scroll-padding-top: 24px; }
body { margin: 0; background: var(--bg); color: var(--fg); font: 16px/1.75 var(--font-body); -webkit-font-smoothing: antialiased; }
::selection { color: var(--fg); background: var(--lime); }
a { color: inherit; text-decoration: none; text-underline-offset: 5px; }
button { font: inherit; cursor: pointer; }
a, button { -webkit-tap-highlight-color: transparent; transition: color var(--motion-fast), background-color var(--motion-fast), transform var(--motion-fast); }
a:focus-visible, button:focus-visible { outline: 3px solid var(--accent); outline-offset: 5px; }
p, h1, h2, h3, figure { margin: 0; }
p { text-wrap: pretty; }
h1, h2, h3 { font-family: var(--font-display); font-weight: 700; text-wrap: balance; }
h2 { font-size: clamp(28px, 3vw, 38px); line-height: 1.3; letter-spacing: -.025em; }
h3 { font-size: 23px; line-height: 1.4; letter-spacing: -.015em; }
img { display: block; max-width: 100%; height: auto; }
.container { width: min(calc(100% - 96px), var(--container-max)); margin-inline: auto; }
.section-pad { padding-block: 64px; }
section[id], figure[id] { scroll-margin-top: 28px; }
.section-grid { display: grid; grid-template-columns: minmax(0, 4fr) minmax(0, 7fr); gap: 7%; }
.hero > *, .section-grid > *, .contact-layout > *, .ai-hero-layout > *, .case-row > * { min-width: 0; }
.eyebrow { font-size: 12px; font-weight: 600; line-height: 1.6; letter-spacing: .04em; }
.section-heading .eyebrow { margin-bottom: 18px; }
.section-intro { color: var(--fg-2); font-size: 15px; margin-top: 23px; max-width: 28em; }
.skip-link { position: absolute; top: -100px; left: 20px; z-index: 3; padding: 12px 18px; background: var(--lime); border: 1px solid var(--fg); }
.skip-link:focus { top: 12px; }

/* 页眉：名字之外的品牌签名；国际版保留原生 URL。 */
.site-header { min-height: 88px; display: flex; justify-content: space-between; align-items: center; gap: 12px 24px; border-bottom: 1px solid var(--border); }
.wordmark { font: 800 29px/1 var(--font-latin); letter-spacing: -.05em; }
.brand-dot { color: var(--accent); }
.site-nav { display: flex; flex-wrap: wrap; align-items: center; gap: 4px 30px; }
.site-nav a { min-height: 44px; display: inline-flex; align-items: center; gap: 6px; font-size: 14px; font-weight: 600; }
.site-nav a:hover, .site-footer a:hover, .back-link:hover { text-decoration: underline; }

/* 个人首屏：姓名和角色构成主视觉；没有项目图或项目名。 */
.hero { display: grid; grid-template-columns: minmax(0, 1.16fr) minmax(0, 1fr); gap: 6%; padding-top: 56px; padding-bottom: 64px; align-items: stretch; }
.hero-copy { padding-block: 8px; }
.personal-title { margin-top: 18px; }
.personal-name { display: block; font: 800 clamp(78px, 8.3vw, 116px)/.95 var(--font-latin); letter-spacing: -.065em; }
.name-period { color: var(--accent); }
.personal-role { display: block; font-size: 20px; line-height: 1.6; letter-spacing: 0; margin-top: 15px; }
.personal-role [lang="en"] { font-family: var(--font-latin); font-weight: 800; letter-spacing: .015em; }
/* 两页共享可见解释，身份缩写与中文说明靠近，手机上自然换行。 */
.fde-explainer { color: var(--fg-2); font-size: 14px; line-height: 1.85; max-width: 39em; margin-top: 18px; }
.fde-explainer strong { color: var(--fg); margin-right: .4em; }
.hero-statement { margin-top: 31px; font-size: clamp(28px, 2.8vw, 39px); line-height: 1.4; letter-spacing: -.03em; }
.hero-intro { color: var(--fg-2); margin-top: 21px; font-size: 16px; line-height: 1.85; max-width: 34em; }
.hero-actions { display: flex; flex-wrap: wrap; align-items: center; gap: 12px 25px; margin-top: 27px; }
.btn { display: inline-flex; align-items: center; justify-content: center; min-height: 50px; padding: 12px 21px; gap: 22px; background: transparent; border: 1px solid var(--fg); border-radius: 8px; font-size: 15px; line-height: 1.6; font-weight: 600; letter-spacing: .02em; }
.btn-primary { background: var(--fg); color: var(--surface); }
.btn-primary:hover { background: var(--fg-2); transform: translateY(-2px); }
.btn:active, .copy-button:active { transform: translateY(1px); }
.btn:disabled, .copy-button:disabled { opacity: .65; cursor: progress; transform: none; }
.text-link { display: inline-flex; align-items: center; min-height: 44px; gap: 14px; font-size: 14px; font-weight: 600; text-decoration: underline; text-decoration-color: var(--border); }
.text-link:hover { text-decoration-color: var(--fg); }
.hero-note { color: var(--fg-2); font-size: 12px; margin-top: 23px; }
.role-board { background: var(--lime); border-radius: 8px 48px 8px 8px; padding: 30px 32px; display: flex; flex-direction: column; justify-content: space-between; }
/* 中文方法图：四字一行，字号低于姓名，避免沿用拉丁大字的尺寸。 */
.board-label { font: 600 12px/1.7 var(--font-body); letter-spacing: .02em; }
.role-monogram { font: 800 clamp(40px, 4.5vw, 60px)/1.25 var(--font-display); letter-spacing: -.035em; margin-top: 24px; }
.board-description { font-size: 17px; font-weight: 600; line-height: 1.8; margin-top: 16px; }
.role-nodes { list-style: none; margin: 25px 0 0; padding: 0; }
.role-nodes li { display: grid; grid-template-columns: 112px minmax(0, 1fr); align-items: baseline; gap: 16px; padding: 14px 0; border-top: 1px solid var(--fg); }
.role-nodes strong { font-size: 16px; font-weight: 700; }
.role-nodes span { font-size: 13px; line-height: 1.6; }

/* 服务与经历：两项服务上下展开，白色区块与瓷白交错，依靠对齐和字重分层。 */
.services, .work-section, .scenarios { background: var(--surface); }
.service-row { padding: 0 0 26px; }
.service-row + .service-row { border-top: 2px solid var(--fg); padding: 26px 0 0; }
.service-row h3 { margin-bottom: 14px; }
.service-row p, .about-copy > p, .delivery-copy > p { color: var(--fg-2); font-size: 15px; max-width: 44em; }
.service-row .service-note { font-size: 14px; margin-top: 12px; }
.service-row .text-link { margin-top: 12px; }
.about-copy .role-explanation { margin-top: 16px; font-size: 14px; }
.experience-list, .questions { margin: 24px 0 0; padding: 0; }
.experience-list > div, .questions > div { display: grid; grid-template-columns: 100px minmax(0, 1fr); gap: 22px; padding-block: 13px; border-top: 1px solid var(--border); }
.experience-list dt, .questions dt { font-size: 14px; font-weight: 700; }
.experience-list dd, .questions dd { margin: 0; color: var(--fg-2); font-size: 14px; }

/* 相关实践：同级案例行，媒体列小于整行三分之一；ERP 仅用文字标记。 */
.work-heading { display: flex; align-items: baseline; justify-content: space-between; gap: 20px; margin-bottom: 28px; }
.case-row { display: grid; grid-template-columns: minmax(0, 1fr) minmax(0, 2.3fr); gap: 36px; padding-block: 28px; border-top: 1px solid var(--border); }
.case-row:last-child { padding-bottom: 0; }
.case-media { align-self: start; }
.screenshot-link { display: block; border: 1px solid var(--border); padding: 8px; border-radius: 8px; background: var(--bg); }
.screenshot-link:hover { outline: 2px solid var(--fg); outline-offset: 2px; }
.case-media figcaption { color: var(--fg-2); font-size: 12px; margin-top: 9px; }
.case-copy h3 { margin-bottom: 12px; }
.case-copy > p { color: var(--fg-2); font-size: 15px; max-width: 48em; }
.case-copy .project-scope { font-size: 13px; margin-top: 12px; }
.case-copy .text-link { margin-top: 10px; }
.case-title-row { display: flex; align-items: baseline; flex-wrap: wrap; gap: 8px 18px; }
.demo-label { font-size: 12px; font-weight: 600; text-decoration: underline; text-underline-offset: 4px; }
.erp-mark { width: 100%; min-height: 145px; background: var(--surface-soft); padding: 24px; display: flex; flex-direction: column; justify-content: center; gap: 7px; border-radius: 8px; }
.erp-mark > span:first-child { font: 700 28px/1.35 var(--font-display); letter-spacing: -.02em; }
.erp-mark > span:last-child { font-size: 13px; }

/* 合作与交付：三步是连续清单，三问保留费用、周期与维护边界。 */
.cooperation-steps, .delivery-steps { list-style: none; padding: 0; margin: 0; }
.cooperation-steps li, .delivery-steps li { border-top: 1px solid var(--border); padding-block: 17px; }
.cooperation-steps li:first-child, .delivery-steps li:first-child { border-top: 2px solid var(--fg); }
.cooperation-steps h3, .delivery-steps strong { font-size: 18px; font-weight: 700; }
.cooperation-steps p, .delivery-steps p { color: var(--fg-2); font-size: 15px; margin-top: 7px; }
.questions { margin-top: 17px; }
.questions > div { grid-template-columns: 112px minmax(0, 1fr); }

/* 微信为首要动作，邮箱辅助；保留 R4 所有配置与反馈标记。 */
.contact { background: var(--lime); }
.contact-layout { display: grid; grid-template-columns: minmax(0, 1.15fr) minmax(0, 1fr); gap: 8%; align-items: start; }
.contact .eyebrow { margin-bottom: 17px; }
.contact h2 { font-size: clamp(31px, 3.7vw, 48px); line-height: 1.3; }
.contact-description { color: var(--fg-2); margin-top: 22px; font-size: 15px; max-width: 30em; }
.contact-value { min-width: 0; overflow-wrap: anywhere; user-select: all; -webkit-user-select: all; }
.contact .contact-label { margin-bottom: 9px; }
/* 二维码以白色方形面板展示；保留原图颜色和留白，窄屏自然缩小。 */
.wechat-qr { width: 200px; max-width: 100%; margin-bottom: 19px; }
.wechat-qr-image { display: block; padding: 8px; background: #fff; border: 1px solid var(--border); border-radius: 8px; }
.wechat-qr-image img { width: 100%; aspect-ratio: 1; object-fit: contain; }
.wechat-qr figcaption { margin-top: 8px; color: var(--fg-2); font-size: 12px; line-height: 1.65; }
.contact-hint { color: var(--fg-2); font-size: 12px; }
.copy-status { color: var(--fg-2); min-height: 40px; max-width: 36em; font-size: 12px; line-height: 1.65; margin-top: 5px; }
.email-alternative { margin-top: 7px; padding-top: 14px; border-top: 1px solid var(--fg); display: flex; flex-wrap: wrap; align-items: center; gap: 0 14px; }
.email-alternative > .contact-hint { flex-basis: 100%; }
.email-link { display: inline-flex; align-items: center; min-height: 44px; max-width: 100%; gap: 10px; font-size: 15px; }
.email-link:hover { text-decoration: underline; }
.copy-button { display: inline-flex; align-items: center; min-height: 44px; padding: 5px 0; border: 0; background: transparent; color: var(--fg); font-size: 13px; font-weight: 600; text-decoration: underline; text-underline-offset: 5px; }
.copy-button:hover { text-decoration-thickness: 2px; }
.site-footer { display: flex; align-items: center; justify-content: space-between; gap: 12px 24px; min-height: 88px; font-size: 12px; color: var(--fg-2); }
.site-footer a { min-height: 44px; display: inline-flex; align-items: center; gap: 6px; }
.clipboard-helper { position: fixed; inset: 0 auto auto 0; width: 1px; height: 1px; opacity: 0; pointer-events: none; }

/* AI 页：同一套强字重和青柠签名，但不重复首页的大幅方法图。 */
.ai-hero { padding-top: 20px; padding-bottom: 64px; }
.back-link { display: inline-flex; align-items: center; min-height: 44px; font-size: 13px; }
.ai-hero-layout { display: grid; grid-template-columns: minmax(0, 1.8fr) minmax(0, 1fr); gap: 9%; padding-top: 26px; align-items: center; }
.ai-identity { display: flex; flex-wrap: wrap; gap: 6px 16px; align-items: baseline; margin-bottom: 26px; }
.ai-identity > span:first-child { font: 800 34px/1.2 var(--font-latin); letter-spacing: -.05em; }
.ai-identity > span:last-child { font-size: 18px; font-weight: 700; }
.ai-hero-copy > .fde-explainer { margin-top: -12px; margin-bottom: 24px; }
.ai-hero-copy > .eyebrow { margin-bottom: 13px; }
.ai-hero h1 { font-size: clamp(36px, 4vw, 54px); line-height: 1.35; letter-spacing: -.035em; }
.ai-hero .btn { margin-top: 26px; }
.ai-signature { padding: 30px; background: var(--lime); border-radius: 8px 32px 8px 8px; max-width: 350px; justify-self: end; }
.signature-monogram { display: block; font: 800 clamp(32px, 4vw, 46px)/1.3 var(--font-display); letter-spacing: -.03em; }
.ai-signature p { font-size: 20px; font-weight: 700; margin-top: 22px; }
.signature-note { display: block; font-size: 12px; border-top: 1px solid var(--fg); padding-top: 17px; margin-top: 20px; }
.scenario-row { padding-block: 22px; border-top: 1px solid var(--border); }
.scenario-row:first-child { padding-top: 0; border-top: 0; }
.scenario-row:last-child { padding-bottom: 0; }
.scenario-row h3 { font-size: 21px; margin-bottom: 9px; }
.scenario-row p { color: var(--fg-2); font-size: 15px; }
.collaborator-note { margin-bottom: 25px; }
.mobile-break { display: none; }

/* 平板：姓名与方法图上下分组；正文保持标题/内容双栏，减少嵌套密度。 */
@media (max-width: 900px) {
  .container { width: calc(100% - 64px); }
  .section-pad { padding-block: 48px; }
  .hero { grid-template-columns: 1fr; gap: 30px; padding-block: 42px 48px; }
  .personal-name { font-size: 100px; }
  .hero-statement { font-size: 36px; }
  .hero-intro { max-width: 39em; }
  .role-board { display: grid; grid-template-columns: minmax(0, 1fr) minmax(0, 1.2fr); gap: 15px 32px; padding: 28px; }
  .board-label { grid-column: 1 / -1; }
  .role-monogram { font-size: clamp(32px, 4.8vw, 44px); margin-top: 7px; }
  .board-description { grid-column: 1; font-size: 17px; margin-top: 0; }
  .role-nodes { grid-column: 2; grid-row: 2 / 4; margin: 0; align-self: center; }
  .role-nodes li { grid-template-columns: 1fr; gap: 3px; padding-block: 12px; }
  .section-grid { grid-template-columns: minmax(0, 3fr) minmax(0, 5fr); gap: 36px; }
  .section-heading h2 { font-size: 29px; }
  .experience-list > div, .questions > div { grid-template-columns: 1fr; gap: 4px; }
  .case-row { gap: 26px; }
  .erp-mark { padding: 20px; min-height: 120px; }
  .erp-mark > span:first-child { font-size: 24px; }
  .contact-layout { grid-template-columns: minmax(0, 1fr) minmax(0, 1fr); gap: 35px; }
  .wechat-account { font-size: 28px; }
  .ai-hero-layout { grid-template-columns: minmax(0, 1.8fr) minmax(0, 1fr); gap: 32px; }
  .ai-signature { padding: 22px; }
  .ai-signature p { font-size: 17px; }
  .signature-note { font-size: 11px; }
}

/* 360 / 390 手机：先完整读到姓名、解释与主动作，再出现角色图；案例缩略图仍不超过三分之一。 */
@media (max-width: 639px) {
  .container { width: calc(100% - 40px); }
  .section-pad { padding-block: 38px; }
  .site-header { min-height: 76px; flex-wrap: wrap; padding-block: 12px; gap: 6px 16px; }
  .wordmark { font-size: 25px; }
  .site-nav { gap: 0 14px; }
  .site-nav a { font-size: 12px; gap: 4px; }
  .hero { padding-block: 30px 38px; gap: 27px; }
  .hero-copy { padding: 0; }
  .personal-title { margin-top: 15px; }
  .personal-name { font-size: clamp(72px, 19vw, 90px); }
  .personal-role { font-size: 17px; margin-top: 10px; }
  .hero-statement { font-size: clamp(26px, 6.6vw, 31px); margin-top: 23px; line-height: 1.45; }
  .hero-intro { font-size: 15px; margin-top: 16px; line-height: 1.8; }
  .hero-actions { margin-top: 22px; gap: 8px 22px; }
  .hero-note { font-size: 11px; margin-top: 17px; }
  .btn { font-size: 14px; padding-inline: 18px; }
  .text-link { font-size: 13px; gap: 10px; }
  .role-board { display: flex; padding: 24px; border-top-right-radius: 32px; gap: 0; }
  .board-label { font-size: 10px; }
  .role-monogram { font-size: clamp(38px, 11vw, 46px); margin-top: 20px; }
  .board-description { margin-top: 12px; font-size: 16px; }
  .role-nodes { margin-top: 22px; align-self: stretch; }
  .role-nodes li { grid-template-columns: 96px minmax(0, 1fr); gap: 10px; }
  .role-nodes strong { font-size: 14px; }
  .role-nodes span { font-size: 12px; }
  .section-grid, .contact-layout { grid-template-columns: 1fr; gap: 25px; }
  .section-heading .eyebrow { margin-bottom: 12px; }
  .section-heading h2 { font-size: 29px; }
  .section-intro { margin-top: 15px; max-width: none; }
  .service-row h3 { font-size: 22px; }
  .service-row { padding-bottom: 22px; }
  .service-row + .service-row { padding-top: 22px; }
  .experience-list > div { grid-template-columns: 86px minmax(0, 1fr); gap: 14px; }
  .work-heading { display: block; margin-bottom: 20px; }
  .work-heading .eyebrow { margin-bottom: 12px; }
  .work-heading h2 { font-size: 29px; }
  .case-row { grid-template-columns: minmax(0, 1fr) minmax(0, 2.3fr); gap: 16px; padding-block: 23px; }
  .screenshot-link { padding: 3px; }
  .case-copy h3 { font-size: 20px; margin-bottom: 10px; }
  .case-copy > p { font-size: 14px; }
  .case-copy .project-scope { font-size: 12px; }
  .case-media figcaption { font-size: 10px; line-height: 1.7; }
  .erp-mark { min-height: 90px; padding: 12px 7px; gap: 7px; }
  .erp-mark > span:first-child { font-size: 18px; }
  .erp-mark > span:last-child { font-size: 11px; }
  .case-title-row { gap: 0 10px; margin-bottom: 10px; }
  .case-title-row h3 { margin-bottom: 0; }
  .questions > div { grid-template-columns: 100px minmax(0, 1fr); gap: 15px; }
  .contact-layout { gap: 29px; }
  .contact h2 { font-size: 35px; }
  .contact-description { margin-top: 17px; }
  .wechat-qr { width: 196px; }
  .site-footer { flex-wrap: wrap; gap: 0 12px; padding-block: 17px; }
  .site-footer > p:nth-child(2) { display: none; }
  .ai-hero { padding-block: 14px 38px; }
  .ai-hero-layout { grid-template-columns: 1fr; gap: 25px; padding-top: 18px; }
  .ai-identity { margin-bottom: 21px; }
  .ai-identity > span:first-child { font-size: 31px; }
  .ai-hero h1 { font-size: clamp(30px, 8.1vw, 38px); }
  .ai-hero .btn { margin-top: 23px; }
  .ai-signature { max-width: none; width: 100%; display: grid; grid-template-columns: 106px minmax(0, 1fr); gap: 8px 16px; padding: 22px; align-items: center; }
  .signature-monogram { font-size: 32px; grid-row: 1 / 3; }
  .ai-signature p { font-size: 16px; margin-top: 0; }
  .ai-signature p br { display: none; }
  .signature-note { border: 0; padding: 0; margin: 0; font-size: 11px; }
  .scenario-row h3 { font-size: 21px; }
  .mobile-break { display: initial; }
}

/* 尊重减少动效偏好；不影响原生锚点、焦点或复制反馈。 */
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  *, *::before, *::after { transition: none !important; animation: none !important; }
  .btn-primary:hover, .btn:active, .copy-button:active { transform: none; }
}

/* R7 独立角色说明：字号与结构自成模块，不影响首屏、服务、二维码或其他内容区。 */
.fde-section { padding-block: 64px; background: var(--surface-soft); border-block: 1px solid var(--border); }
.fde-layout { display: grid; grid-template-columns: minmax(0, 1.05fr) minmax(0, 1fr); align-items: start; gap: 48px; }
.fde-layout > * { min-width: 0; }
.fde-title { font-size: 42px; line-height: 1.35; letter-spacing: -.025em; margin-bottom: 24px; }
.fde-section p, .fde-section .fde-link { font-size: 16px; line-height: 1.8; }
.fde-copy p { color: var(--fg-2); max-width: 52ch; overflow-wrap: anywhere; }
.fde-copy p + p { margin-top: 18px; }
.fde-example { background: var(--lime); padding: 28px; border-radius: 8px; }
.fde-example-title { font-size: 18px; line-height: 1.6; margin-bottom: 18px; }
.fde-example-copy { color: var(--fg-2); }
/* 场景改用连续叙述，段落之间留出阅读间距。 */
.fde-example p + p { margin-top: 16px; }
.fde-link { display: inline-flex; align-items: center; flex-wrap: wrap; gap: 10px; min-height: 44px; margin-top: 16px; font-weight: 600; text-decoration: underline; text-underline-offset: 5px; }
.fde-link:hover { text-decoration-thickness: 2px; }

/* 受众说明：角色和问题分列，具体做法紧接问题，避免堆成同款卡片。 */
.fde-audience-heading { display: grid; grid-template-columns: minmax(0, 1.05fr) minmax(0, 1fr); gap: 48px; align-items: end; }
.fde-audience .fde-audience-label { font-size: 14px; font-weight: 600; margin-bottom: 16px; }
.fde-audience .fde-title { margin-bottom: 0; }
.fde-audience-intro { color: var(--fg-2); max-width: 32em; }
.fde-audience-nav { display: flex; flex-wrap: wrap; gap: 0 28px; margin-block: 24px 12px; }
.fde-audience-nav a { display: inline-flex; align-items: center; min-height: 44px; font-size: 15px; font-weight: 600; text-decoration: underline; text-underline-offset: 5px; }
.fde-audience-row { display: grid; grid-template-columns: 170px minmax(0, 1fr); gap: 30px; padding-block: 27px; border-top: 1px solid var(--border); scroll-margin-top: 24px; }
.fde-audience .fde-persona { font-size: 15px; font-weight: 600; }
.fde-audience-row h3 { font-size: 22px; line-height: 1.5; margin-bottom: 12px; }
.fde-audience-row > div > p { color: var(--fg-2); max-width: 48em; }
.fde-audience-row strong { color: var(--fg); font-weight: 600; }
.fde-role-note { display: grid; grid-template-columns: minmax(0, 1fr) auto; gap: 36px; align-items: center; border-top: 2px solid var(--fg); padding-top: 30px; margin-top: 8px; }
.fde-role-note h3 { font-size: 22px; margin-bottom: 12px; }
.fde-role-note p { color: var(--fg-2); max-width: 48em; overflow-wrap: anywhere; }

/* 平板上下分组，保证定义和场景示意各自拥有足够的阅读宽度。 */
@media (max-width: 900px) {
  .fde-section { padding-block: 48px; }
  .fde-layout { grid-template-columns: 1fr; gap: 28px; }
  .fde-title { font-size: 38px; }
  .fde-copy p { max-width: 65ch; }
  .fde-audience-heading { grid-template-columns: 1fr; gap: 20px; }
  .fde-audience-row { grid-template-columns: 140px minmax(0, 1fr); gap: 24px; }
  .fde-role-note { grid-template-columns: 1fr; gap: 24px; justify-items: start; }
}

/* 手机标题约 30px；正文始终为 16px，定义和举例自然上下排列。 */
@media (max-width: 639px) {
  .fde-section { padding-block: 38px; }
  .fde-title { font-size: 30px; margin-bottom: 20px; }
  .fde-example { padding: 20px; }
  .fde-example-title { margin-bottom: 15px; }
  .fde-audience-nav { gap: 0 20px; margin-top: 18px; }
  .fde-audience-row { grid-template-columns: 1fr; gap: 10px; padding-block: 24px; }
  .fde-audience-row h3 { font-size: 21px; margin-bottom: 10px; }
  .fde-role-note { padding-top: 24px; }
}

/* 长辈阅读：仅调整人工智能详情页，正文加大、行距放宽，说明不再用小字。 */
body.ai-page {
  --fg-2: #2f5d4e;
  --muted: #2f5d4e;
  font-size: 24px;
  line-height: 1.9;
}
body.ai-page p { font-size: 24px; line-height: 1.9; }
body.ai-page h2 { font-size: clamp(36px, 3.2vw, 44px); line-height: 1.45; letter-spacing: 0; }
body.ai-page h3 { font-size: 28px; line-height: 1.5; letter-spacing: 0; }
body.ai-page .ai-hero h1 { font-size: clamp(40px, 4vw, 56px); line-height: 1.45; letter-spacing: -.01em; }
body.ai-page .hero-intro,
body.ai-page .section-intro,
body.ai-page .contact-description,
body.ai-page .scenario-row p,
body.ai-page .delivery-copy > p,
body.ai-page .delivery-steps p,
body.ai-page .fde-section p { font-size: 24px; line-height: 1.9; }
body.ai-page .eyebrow,
body.ai-page .signature-note,
body.ai-page .contact-hint,
body.ai-page .copy-status,
body.ai-page .wechat-qr figcaption,
body.ai-page .site-footer,
body.ai-page .site-footer p { font-size: 20px; line-height: 1.9; letter-spacing: 0; }
body.ai-page .ai-identity > span:last-child { font-size: 20px; line-height: 1.9; }
body.ai-page .ai-signature p { font-size: 22px; line-height: 1.9; }
body.ai-page .delivery-steps strong { font-size: 26px; line-height: 1.6; }
body.ai-page .questions dt,
body.ai-page .questions dd { font-size: 24px; line-height: 1.9; }
body.ai-page .fde-example-title { font-size: 26px; line-height: 1.6; }
body.ai-page .fde-title { font-size: 44px; line-height: 1.45; letter-spacing: 0; }

/* 导航、返回、详情链接与邮箱有更大的点按区域；联系主按钮单独加高。 */
body.ai-page a { font-size: 20px; }
body.ai-page .wordmark,
body.ai-page .site-nav a,
body.ai-page .site-footer a,
body.ai-page .back-link,
body.ai-page .text-link,
body.ai-page .fde-link,
body.ai-page .email-link {
  display: inline-flex;
  align-items: center;
  min-height: 52px;
  max-width: 100%;
  line-height: 1.8;
}
body.ai-page .wordmark { font-size: 36px; }
body.ai-page .site-nav a,
body.ai-page .back-link,
body.ai-page .text-link,
body.ai-page .fde-link { font-size: 20px; }
body.ai-page .btn { min-height: 60px; padding: 14px 24px; font-size: 22px; line-height: 1.6; }
body.ai-page .copy-button { min-height: 52px; padding: 8px 12px; font-size: 20px; line-height: 1.8; }
body.ai-page .email-link { flex-wrap: wrap; font-size: 24px; }
body.ai-page .copy-status { min-height: 38px; }
body.ai-page .wechat-qr { width: 280px; max-width: 100%; }
body.ai-page .contact-layout,
body.ai-page .section-grid,
body.ai-page .ai-hero-layout,
body.ai-page .fde-layout { gap: 48px; }
body.ai-page .fde-example { padding: 32px; }

/* 中屏提前单列，避免放大文字仍被挤在窄栏中。 */
@media (max-width: 1100px) {
  body.ai-page .section-grid,
  body.ai-page .ai-hero-layout,
  body.ai-page .fde-layout,
  body.ai-page .contact-layout { grid-template-columns: 1fr; gap: 32px; }
  body.ai-page .section-heading h2 { font-size: 38px; }
  body.ai-page .questions > div { grid-template-columns: 1fr; gap: 8px; padding-block: 20px; }
  body.ai-page .ai-signature { width: 100%; max-width: 560px; justify-self: start; }
  body.ai-page .fde-copy p { max-width: 36em; }
}

/* 手机正文保持22px；提示、导航和反馈至少20px，不随旧断点缩小。 */
@media (max-width: 639px) {
  body.ai-page { font-size: 22px; line-height: 1.9; }
  body.ai-page p,
  body.ai-page .hero-intro,
  body.ai-page .section-intro,
  body.ai-page .contact-description,
  body.ai-page .scenario-row p,
  body.ai-page .delivery-copy > p,
  body.ai-page .delivery-steps p,
  body.ai-page .fde-section p,
  body.ai-page .questions dt,
  body.ai-page .questions dd { font-size: 22px; line-height: 1.9; }
  body.ai-page .eyebrow,
  body.ai-page .signature-note,
  body.ai-page .contact-hint,
  body.ai-page .copy-status,
  body.ai-page .wechat-qr figcaption,
  body.ai-page .site-footer,
  body.ai-page .site-footer p { font-size: 20px; line-height: 1.9; }
  body.ai-page .site-header { flex-direction: column; align-items: flex-start; gap: 8px; }
  body.ai-page .site-nav { width: 100%; justify-content: space-between; gap: 6px 12px; }
  body.ai-page .wordmark { font-size: 32px; }
  body.ai-page .site-nav a { font-size: 20px; }
  body.ai-page .ai-hero h1 { font-size: 34px; }
  body.ai-page .section-heading h2,
  body.ai-page .fde-title,
  body.ai-page .contact h2 { font-size: 34px; line-height: 1.5; }
  body.ai-page .scenario-row h3,
  body.ai-page .fde-example-title,
  body.ai-page .delivery-steps strong { font-size: 26px; line-height: 1.6; }
  body.ai-page .ai-signature { display: block; padding: 24px; }
  body.ai-page .signature-monogram { font-size: 36px; line-height: 1.4; }
  body.ai-page .ai-signature p { margin-top: 18px; font-size: 22px; }
  body.ai-page .signature-note { margin-top: 16px; padding-top: 16px; border-top: 1px solid var(--fg); }
  body.ai-page .fde-example { padding: 24px; }
  body.ai-page .email-alternative { gap: 4px 12px; }
  body.ai-page .site-footer { align-items: flex-start; }
}