:root{
    --bg:           #080D1F;
    --bg-soft:      #111827;
    --bg-raised:    #1A2035;
    --ink:          #FFFFFF;
    --ink-soft:     #D9D9E3;
    --ink-mute:     #8A8A95;
    --ink-subtle:   #5A5A65;
    --accent:       #0077ED;
    --accent-hover: #0090FF;
    --accent-soft:  rgba(0, 119, 237, 0.10);
    --accent-glow:  rgba(0, 119, 237, 0.22);
    --accent-deep:  #005BB5;
    --success:      #22C55E;
    --info:         #38BDF8;
    --warning:      #F59E0B;
    --line:         rgba(255, 255, 255, 0.07);
    --line-strong:  rgba(255, 255, 255, 0.14);

    /* Font stack: Inter 是品牌字体（从 Google Fonts 加载）；
       中文 fallback 必须显式声明——浏览器自带的 system-ui 在 iOS 是 SF Pro
       (英文) + PingFang SC (中文)，两者 baseline / 字宽不同 → 中英文混排
       看起来「参差」；安卓 system-ui 是 Roboto (英文) + Noto Sans CJK (中文)，
       Noto 家族设计上保持中英文字宽统一 → 看起来「整齐」。
       解决方案：iOS 优先用 PingFang SC 接管（苹方是设计为中英文字宽统一的多
       语言字体），安卓优先用 Noto Sans CJK / 思源黑体；中间塞 -apple-system
       和 BlinkMacSystemFont 让 iOS 显式认 SF Pro。 */
    --ff-display: 'Space Grotesk',
                  -apple-system, BlinkMacSystemFont, system-ui,
                  "PingFang SC", "Hiragino Sans GB",
                  "Microsoft YaHei", "Source Han Sans CN", "Noto Sans CJK SC",
                  sans-serif;
    --ff-body:    'Inter',
                  -apple-system, BlinkMacSystemFont, system-ui,
                  "PingFang SC", "Hiragino Sans GB",
                  "Microsoft YaHei", "Source Han Sans CN", "Noto Sans CJK SC",
                  Roboto,
                  sans-serif;
    --ff-mono:    'IBM Plex Mono', ui-monospace, "SF Mono", Menlo, monospace;

    /* Font-size variables. Default values mirror the original hardcoded
       sizes so the site renders correctly even before the admin-injected
       overrides in base.html <style> block are applied (e.g. Vercel cold
       start, cached CSS without matching HTML). Admin overrides these via
       the dynamic :root block in base.html. */
    --fs-base:          clamp(15px, 0.9375rem + 0.125vw, 18px);
    --fs-nav:           17px;
    --fs-hero-title-admin:    clamp(36px, 7vw, 72px);
    --fs-hero-subtitle: clamp(15px, 1.1vw, 17px);
    --fs-section-title-admin: clamp(34px, 5vw, 64px);
    --fs-body:          clamp(15px, 0.9375rem + 0.125vw, 16px);
    --fs-card-title:    clamp(20px, 2vw, 24px);
    --fs-card-desc:     14px;

    /* Public aliases consumed by .hero-title / .section-title (F5'/D1).
       The mobile media query near the end of this file re-derives these
       responsively; the -admin vars carry the raw (admin or fallback) value. */
    --fs-hero-title:    var(--fs-hero-title-admin);
    --fs-section-title: var(--fs-section-title-admin);

    --sp-1: 8px;
    --sp-2: 16px;
    --sp-3: 24px;
    --sp-4: 48px;
    --sp-5: 96px;
    --sp-6: 160px;
  }

  /* ============ LIGHT THEME ============ */
  [data-theme="light"]{
    --bg:           #F5F7FA;
    --bg-soft:      #EBEEF3;
    --bg-raised:    #FFFFFF;
    --ink:          #111827;
    --ink-soft:     #374151;
    --ink-mute:     #6B7280;
    --ink-subtle:   #9CA3AF;
    --accent:       #0062C4;
    --accent-hover: #0077ED;
    --accent-soft:  rgba(0, 98, 196, 0.08);
    --accent-glow:  rgba(0, 98, 196, 0.12);
    --accent-deep:  #004A99;
    --success:      #16A34A;
    --info:         #0284C7;
    --warning:      #D97706;
    --line:         rgba(0, 0, 0, 0.07);
    --line-strong:  rgba(0, 0, 0, 0.12);
  }

  /* Light theme nav */
  [data-theme="light"] .nav {
    background: rgba(245, 247, 250, 0.82);
    box-shadow: 0 1px 3px rgba(0,0,0,0.06);
  }
  [data-theme="light"] .mobile-panel {
    background: rgba(245, 247, 250, 0.95);
  }
  [data-theme="light"] .mobile-panel-overlay {
    background: rgba(0, 0, 0, 0.3);
  }

  /* Light theme hero */
  [data-theme="light"] .hero-bg::after {
    background: transparent;
  }
  [data-theme="light"] .hero-grid {
    background-image:
      linear-gradient(to right, rgba(0, 0, 0, 0.03) 1px, transparent 1px),
      linear-gradient(to bottom, rgba(0, 0, 0, 0.03) 1px, transparent 1px);
  }
  [data-theme="light"] .hero-noise { opacity: 0.02; }
  [data-theme="light"] .hero-corner-marks::before,
  [data-theme="light"] .hero-corner-marks::after { border-color: var(--accent); opacity: 0.5; }
  [data-theme="light"] .hero-field-glow {
    background:
      radial-gradient(ellipse 80% 50% at 50% 60%, rgba(0, 98, 196, 0.04) 0%, transparent 70%),
      radial-gradient(ellipse 40% 30% at 30% 70%, rgba(0, 98, 196, 0.02) 0%, transparent 60%),
      radial-gradient(ellipse 40% 30% at 70% 70%, rgba(0, 98, 196, 0.02) 0%, transparent 60%);
  }
  [data-theme="light"] .hero-field-lines {
    border-color: rgba(0, 98, 196, 0.06);
    border-top-color: rgba(0, 98, 196, 0.1);
  }
  [data-theme="light"] .hero-field-lines::before { background: rgba(0, 98, 196, 0.06); }
  [data-theme="light"] .hero-field-lines::after { border-color: rgba(0, 98, 196, 0.05); }

  /* Light theme footer */
  [data-theme="light"] footer {
    background: #111827;
    color: #D1D5DB;
  }
  [data-theme="light"] .footer-col-label { color: #9CA3AF; }
  [data-theme="light"] .footer-list a:hover { color: #FFFFFF; }
  [data-theme="light"] .footer-brand-name { color: #FFFFFF; }
  [data-theme="light"] .footer-bottom { border-top-color: rgba(255,255,255,0.08); color: #9CA3AF; }
  [data-theme="light"] .footer-social a { color: #9CA3AF; }
  [data-theme="light"] .footer-social a:hover { color: #FFFFFF; }
  [data-theme="light"] .footer-contact-item { color: #9CA3AF; }
  [data-theme="light"] .footer-contact-item a { color: #D1D5DB; }
  [data-theme="light"] .footer-contact-item a:hover { color: #FFFFFF; }

  /* Light theme cards need subtle shadow */
  [data-theme="light"] .about-pillar,
  [data-theme="light"] .about-optic-card,
  [data-theme="light"] .about-service-card {
    box-shadow: 0 1px 3px rgba(0,0,0,0.06), 0 1px 2px rgba(0,0,0,0.04);
  }
  [data-theme="light"] .about-pillar:hover,
  [data-theme="light"] .about-optic-card:hover,
  [data-theme="light"] .about-service-card:hover {
    box-shadow: 0 8px 24px -8px rgba(0,0,0,0.1);
  }

  /* Theme toggle button */
  .theme-toggle {
    display: flex; align-items: center; justify-content: center;
    width: 36px; height: 36px; border-radius: 8px;
    border: 1px solid var(--line-strong);
    background: transparent; cursor: pointer;
    transition: border-color 0.2s, background 0.2s;
    flex-shrink: 0;
  }
  .theme-toggle:hover { border-color: var(--accent); background: var(--accent-soft); }
  .theme-toggle svg { width: 18px; height: 18px; color: var(--ink-soft); transition: color 0.2s; }
  .theme-toggle:hover svg { color: var(--accent); }

  /* Body transition for smooth theme switch */
  body, .nav, .hero-bg::after { transition: background-color 0.4s ease, color 0.3s ease, border-color 0.3s ease; }

  /* Language switcher */
  .lang-switch {
    position: relative;
    flex-shrink: 0;
  }
  .lang-switch-btn {
    display: flex;
    align-items: center;
    gap: 6px;
    padding: 6px 10px;
    border: 1px solid var(--line-strong);
    border-radius: 8px;
    background: transparent;
    cursor: pointer;
    transition: border-color 0.2s, background 0.2s;
    color: var(--ink-soft);
    font-family: var(--ff-mono);
    font-size: 11px;
    font-weight: 500;
    letter-spacing: 0.06em;
  }
  .lang-switch-btn:hover { border-color: var(--accent); background: var(--accent-soft); }
  .lang-switch-menu {
    display: none;
    position: absolute;
    top: calc(100% + 8px);
    right: 0;
    background: var(--bg-raised);
    border: 1px solid var(--line-strong);
    border-radius: 8px;
    min-width: 160px;
    z-index: 100;
    overflow: hidden;
    box-shadow: 0 8px 24px -8px rgba(0,0,0,0.3);
  }
  .lang-switch-menu.open { display: block; }
  .lang-switch-option {
    display: block;
    padding: 10px 16px;
    font-family: var(--ff-mono);
    font-size: 12px;
    color: var(--ink-soft);
    text-decoration: none;
    transition: background 0.15s, color 0.15s;
  }
  .lang-switch-option:hover { background: var(--accent-soft); color: var(--accent); }
  .lang-switch-option.active { color: var(--accent); font-weight: 600; }

  /* RTL support for Arabic */
  [dir="rtl"] .nav-links { flex-direction: row-reverse; }
  [dir="rtl"] .nav-brand { order: 1; }
  [dir="rtl"] .nav-actions { flex-direction: row-reverse; }
  [dir="rtl"] .hero-content { text-align: right; }
  [dir="rtl"] .footer-grid { direction: rtl; }
  [dir="rtl"] .footer-bottom { flex-direction: row-reverse; }
  [dir="rtl"] .lang-switch-menu { right: auto; left: 0; }
  [dir="rtl"] .hero-corner-marks { transform: scaleX(-1); }
  [dir="rtl"] .home-preview-card.reversed .home-preview-img { order: 1; }
  [dir="rtl"] .home-preview-card.reversed .home-preview-text { order: 2; }

  .home-preview-section {
    padding: 48px 0 0;
  }
  .home-preview-card {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 0;
    border: 1px solid var(--line);
    margin-bottom: 0;
    transition: border-color 0.3s;
  }
  .home-preview-card:hover {
    border-color: var(--line-strong);
  }
  .home-preview-img {
    overflow: hidden;
    min-height: 320px;
    background: var(--bg);
  }
  .home-preview-img img {
    width: 100%;
    height: 100%;
    object-fit: contain;
    display: block;
    transition: transform 0.5s ease;
  }
  .home-preview-card:hover .home-preview-img img {
    transform: scale(1.03);
  }
  .home-preview-text {
    display: flex;
    flex-direction: column;
    justify-content: center;
    padding: 48px 48px;
    gap: 20px;
  }
  .home-preview-tag {
    font-family: var(--ff-mono);
    font-size: 11px;
    letter-spacing: 0.15em;
    text-transform: uppercase;
    color: var(--accent);
  }
  .home-preview-text h2 {
    font-family: var(--ff-display);
    font-size: clamp(1.4rem, 2.5vw, 1.8rem);
    font-weight: 600;
    color: var(--ink);
    line-height: 1.25;
    margin-bottom: 0;
  }
  .home-preview-text p {
    font-size: 0.95rem;
    line-height: 1.75;
    color: var(--ink-mute);
    max-width: 480px;
  }
  .home-preview-link {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    font-family: var(--ff-mono);
    font-size: 12px;
    font-weight: 500;
    letter-spacing: 0.06em;
    text-transform: uppercase;
    color: var(--accent);
    transition: gap 0.2s;
    margin-top: 4px;
  }
  .home-preview-link:hover {
    gap: 12px;
  }
  .home-preview-link .link-arrow {
    transition: transform 0.2s;
    font-size: 14px;
  }
  .home-preview-link:hover .link-arrow {
    transform: translateX(4px);
  }
  .home-preview-card.reversed .home-preview-img {
    order: 2;
  }
  .home-preview-card.reversed .home-preview-text {
    order: 1;
  }
  @media (max-width: 767px) {
    .home-preview-card,
    .home-preview-card.reversed {
      grid-template-columns: 1fr;
    }
    .home-preview-card .home-preview-img,
    .home-preview-card.reversed .home-preview-img {
      order: -1;
      min-height: 220px;
    }
    .home-preview-card .home-preview-text,
    .home-preview-card.reversed .home-preview-text {
      order: 1;
      padding: 32px 24px;
    }
  }
  [dir="rtl"] .link-arrow { display: inline-block; transform: scaleX(-1); }

  *, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
  html { scroll-behavior: smooth; -webkit-font-smoothing: antialiased; -moz-osx-font-smoothing: grayscale; }
  body {
    font-family: var(--ff-body);
    font-size: var(--fs-base);
    line-height: 1.6;
    color: var(--ink-soft);
    background: var(--bg);
    overflow-x: hidden;
    /* N-10: global long-word protection — emails / model names can no
       longer overflow containers and get silently clipped by
       overflow-x:hidden (same failure mode as P0-1). */
    overflow-wrap: anywhere;
    letter-spacing: -0.005em;
  }
  img { max-width: 100%; display: block; }
  a { color: inherit; text-decoration: none; }
  button { font-family: inherit; cursor: pointer; border: none; background: none; color: inherit; }

  .container { max-width: 1280px; margin: 0 auto; padding: 0 16px; }
  @media (min-width: 768px) { .container { padding: 0 32px; } }

  /* ============ NAV ============ */
  .nav {
    position: fixed;
    top: 0; left: 0; right: 0;
    z-index: 100;
    padding: 8px 0;
    background: rgba(10, 14, 26, 0.18);
    backdrop-filter: saturate(180%) blur(14px);
    -webkit-backdrop-filter: saturate(180%) blur(14px);
    border-bottom: 1px solid rgba(255, 255, 255, 0.06);
  }
  .nav-inner {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 24px;
  }
  .nav-brand {
    font-family: var(--ff-display);
    font-size: 20px;
    font-weight: 600;
    color: var(--ink);
    letter-spacing: -0.03em;
    display: flex; align-items: center; gap: 8px;
  }
  .nav-brand img { height: 40px; width: auto; }
  .nav-links {
    margin-left: auto;
    display: flex; gap: 4px; align-items: center;
    list-style: none;
    margin-top: 0; margin-bottom: 0;
    padding: 0;
  }
  /* Contact lives in the mobile panel only; desktop uses the styled .nav-cta */
  .nav-links .nav-item-contact { display: none; }
  .nav-links a {
    font-family: var(--ff-body);
    font-size: var(--fs-nav);
    font-weight: 600;
    color: var(--ink-soft);
    padding: 6px 12px;
    letter-spacing: 0.01em;
    transition: color 0.2s, background 0.2s;
  }
  .nav-links a:hover { color: var(--accent); }
  .nav-cta {
    display: inline-flex;
    align-items: center;
    gap: 6px;
    font-family: var(--ff-mono);
    font-size: 12px;
    color: var(--ink);
    padding: 8px 14px;
    border: 1px solid var(--line-strong);
    letter-spacing: 0.05em;
    text-transform: uppercase;
    transition: all 0.2s;
    white-space: nowrap;
  }
  .nav-cta:hover { border-color: var(--accent); color: var(--accent); }
  .nav-cta .arrow { transition: transform 0.2s; }
  .nav-cta:hover .arrow { transform: translateX(3px); }

  /* Right-hand nav controls. Hidden below 768px — their functions move
     into the mobile panel (.panel-actions) so nothing is lost. */
  .nav-actions {
    display: flex;
    align-items: center;
    gap: 12px;
    flex-shrink: 0;
  }

  /* Hamburger */
  .hamburger {
    display: flex;
    align-items: center;
    justify-content: center;
    width: 44px;
    height: 44px;
    border: 1px solid var(--line-strong);
    z-index: 110;
    flex-shrink: 0;
  }
  @media (min-width: 768px) { .hamburger { display: none; } }
  .hamburger svg { width: 20px; height: 20px; color: var(--ink); }

  /* Mobile nav bar: keep only brand + hamburger so the bar can never
     overflow a 390px viewport. Nav links, CTA, theme and language all
     move into the mobile panel — no functionality is lost. */
  @media (max-width: 767px) {
    .nav-inner { gap: 12px; }
    .nav-links { display: none; }
    .nav-actions { display: none; }
    .nav-brand img { height: 36px; max-width: 160px; }
    /* N-9: hit areas >=44px via transparent pseudo-elements (WCAG 2.5.8 /
       Apple HIG). Visual sizes are unchanged; only the tappable area grows. */
    .theme-toggle,
    .lang-switch-btn { position: relative; }
    .theme-toggle::after { content: ""; position: absolute; inset: -4px; }
    .lang-switch-btn::after { content: ""; position: absolute; inset: -9px -4px; }
  }

  /* Mobile side panel
     Width: 240px (down from 260px / 300px). Drawer content is just 6 short
     nav links + 2 utility buttons, so 240px is plenty (longest word
     "Products" at 18px ≈ 75px). max-width: 72vw still caps it on very
     narrow devices.
     Bottom padding uses env(safe-area-inset-bottom) — REQUIRES
     `viewport-fit=cover` in the meta viewport tag, otherwise env() returns
     0 and the bottom buttons get hidden under the iOS Home Indicator. */
  .mobile-panel {
    position: fixed;
    top: 0; right: 0;
    /* v1.1.14: 抽屉收紧到「按钮完整 + margin」最窄宽
       估算：Theme 按钮 ~112px (icon 18 + gap 8 + "Theme" 50 + padding 14×2)
             + panel padding 14×2 = 140 → 取 160px 留 6px×2 呼吸 */
    width: 160px;
    max-width: 56vw;
    height: 100vh;
    height: 100dvh;
    /* Glass. Alpha dropped 0.92 -> 0.72: at 0.92 the blur was invisible
       and the panel read as a solid slab. */
    background: rgba(10, 14, 26, 0.72);
    backdrop-filter: saturate(160%) blur(20px);
    -webkit-backdrop-filter: saturate(160%) blur(20px);
    border-left: 1px solid rgba(255, 255, 255, 0.12);
    box-shadow: -24px 0 60px rgba(0, 0, 0, 0.45);
    z-index: 105;
    transform: translateX(100%);
    transition: transform 0.35s ease;
    display: flex;
    flex-direction: column;
    padding: 76px 22px calc(32px + env(safe-area-inset-bottom, 0px));
  }
  .mobile-panel.open { transform: translateX(0); }
  .mobile-panel-close {
    position: absolute;
    top: 24px; right: 24px;
    width: 36px; height: 36px;
    display: flex; align-items: center; justify-content: center;
    border: 1px solid var(--line-strong);
    color: var(--ink);
  }
  .mobile-panel-close svg { width: 16px; height: 16px; }
  .mobile-panel-links {
    list-style: none;
    display: flex;
    flex-direction: column;
    gap: 0;
  }
  .mobile-panel-links li {
    border-bottom: 1px solid var(--line);
  }
  .mobile-panel-links a {
    display: block;
    padding: 14px 0;
    font-family: var(--ff-display);
    font-size: 18px;
    font-weight: 500;
    color: var(--ink);
    letter-spacing: -0.01em;
    transition: color 0.2s;
  }
  .mobile-panel-links a:hover { color: var(--accent); }
  .mobile-panel-overlay {
    position: fixed;
    inset: 0;
    background: rgba(0, 0, 0, 0.5);
    z-index: 104;
    opacity: 0;
    pointer-events: none;
    transition: opacity 0.35s ease;
  }
  .mobile-panel-overlay.open { opacity: 1; pointer-events: auto; }

  /* Utilities parked inside the mobile panel (theme + language).
     Below 768px these are the ONLY place to reach them, since the
     nav bar keeps just the brand and the hamburger. */
  .panel-actions {
    margin-top: auto;
    padding-top: 20px;
    /* N-26: 安卓 WebView（百度 App / 微信内置 / 部分 Chrome）下
       env(safe-area-inset-bottom) 经常返回 0 或不支持，
       仅用 env() 会让主题/语言按钮贴底被遮（实测安卓机被完全遮住）。
       用 max() 兜底：env 支持则取 env+48，不支持则固定 80px，
       80px ≈ 安卓底部导航条(50) + 手势条(24)，任一设备都不会被遮。
       iOS 不加 viewport-fit=cover 时，env 也会返回 0，同样走兜底分支 */
    padding-bottom: max(80px, calc(env(safe-area-inset-bottom, 0px) + 48px));
    border-top: 1px solid var(--line);
    display: flex;
    /* v1.1.14: 用户反馈"按钮太大"，竖向排列 + 抽屉宽度收紧到刚好装下 */
    flex-direction: column;
    align-items: stretch;
    gap: 10px;
    /* 防止 panel 内容过多时被挤到按钮后面 */
    flex-shrink: 0;
  }
  /* v1.1.14: panel 内的 Theme 按钮铺满 + 横向文字对齐 */
  .panel-actions .theme-toggle {
    width: 100%;
    height: 36px;
    padding: 0 14px;
    gap: 8px;
    justify-content: flex-start;
  }
  /* v1.1.14: panel 内的语言切换器 — 与 Theme 按钮完全对齐
     关键：外层 div 清 padding（避免双重 padding 让文字右偏 10px），
     内层 button 自己接管 padding:0 14px，与 Theme 按钮一致 → "EN" 起点 = 14px，
     与上方菜单 "Home" 文字起点（panel padding 14px）完全对齐。
     高度 36px + border-radius 8px + gap:8px 也与 Theme 一致 →
     两按钮视觉同构（图标到文字距离完全相同，Theme 文字 x=294 / Lang 文字 x=294）。 */
  .panel-actions .lang-switch {
    width: 100%;
    padding: 0;
  }
  .panel-actions .lang-switch-btn {
    width: 100%;
    height: 36px;
    padding: 0 14px;
    gap: 8px;
    justify-content: flex-start;
    border-radius: 8px;
  }
  .panel-action-label {
    font-family: var(--ff-mono);
    font-size: 12px;
    letter-spacing: 0.06em;
    color: var(--ink-soft);
  }
  /* The panel utilities sit at the bottom, so open the menu upward */
  .panel-actions .lang-switch-menu {
    top: auto;
    bottom: calc(100% + 8px);
  }
  /* N-22: RTL — mirror the drawer. It must slide in from the LEFT, matching
     the reading direction, otherwise Arabic/Hebrew users get a drawer that
     opens against the text flow.
     `:not(.open)` keeps this from out-specifying `.mobile-panel.open`
     (both would be 0-2-0, so source order would decide). */
  [dir="rtl"] .mobile-panel {
    right: auto;
    left: 0;
    border-left: none;
    border-right: 1px solid rgba(255, 255, 255, 0.12);
    box-shadow: 24px 0 60px rgba(0, 0, 0, 0.45);
  }
  [dir="rtl"] .mobile-panel:not(.open) { transform: translateX(-100%); }
  [dir="rtl"] .mobile-panel-close { right: auto; left: 22px; }
  [dir="rtl"] .panel-actions { flex-direction: row-reverse; }

  /* ============ HERO ============ */
  .hero {
    position: relative;
    min-height: 85vh;
    padding: 100px 0 70px;
    display: flex;
    align-items: center;
    overflow: hidden;
  }
  .hero-bg {
    position: absolute;
    inset: 0;
    z-index: 0;
  }
  .hero-bg::after {
    content: '';
    position: absolute;
    inset: 0;
    background: transparent;
    z-index: 2;
  }
  /* Hero carousel */
  .hero-carousel-track {
    position: absolute;
    inset: 0;
  }
  /* 用 <picture> 切换横版/竖版 hero 后，picture 自身是 inline 元素，会在
     track 内留下一个空行盒；display:contents 让它不参与布局，内部 img 的
     absolute 定位行为与改造前完全一致（N-26）。 */
  .hero-carousel-track > picture { display: contents; }
  .hero-slide {
    width: 100%;
    height: 100%;
    object-fit: cover;
    object-position: center 42%;
    position: absolute;
    inset: 0;
    margin: 0;
    opacity: 0;
    transition: opacity 1.2s ease-in-out;
  }
  .hero-slide.active {
    opacity: 1;
  }
  [data-theme="light"] .hero-slide {
    filter: brightness(0.95);
  }
  @media (min-width: 768px) {
    .hero { min-height: 100vh; min-height: 100svh; } /* N-11: svh 跟随动态视口；100vh 为不支持 svh 的旧浏览器降级（成对，§6.8.3） */
  }
  .hero-grid {
    position: absolute; inset: 0;
    background-image:
      linear-gradient(to right, rgba(255, 255, 255, 0.03) 1px, transparent 1px),
      linear-gradient(to bottom, rgba(255, 255, 255, 0.03) 1px, transparent 1px);
    background-size: 64px 64px;
    mask-image: radial-gradient(ellipse 70% 60% at 50% 45%, rgba(0,0,0,1), transparent 85%);
    -webkit-mask-image: radial-gradient(ellipse 70% 60% at 50% 45%, rgba(0,0,0,1), transparent 85%);
  }
  .hero-noise {
    position: absolute; inset: 0;
    opacity: 0.04;
    background-image:
      radial-gradient(circle at 1px 1px, #fff 1px, transparent 1px);
    background-size: 3px 3px;
  }
  .hero-corner-marks {
    position: absolute; inset: 0;
    pointer-events: none;
  }
  .hero-corner-marks::before,
  .hero-corner-marks::after {
    content: ''; position: absolute;
    width: 60px; height: 60px;
    border: 1px solid var(--accent);
    opacity: 0.6;
  }
  .hero-corner-marks::before {
    top: 100px; left: 32px;
    border-right: none; border-bottom: none;
  }
  .hero-corner-marks::after {
    bottom: 60px; right: 32px;
    border-left: none; border-top: none;
  }
  @media (max-width: 767px) {
    .hero-corner-marks::before, .hero-corner-marks::after { display: none; }
    .hero { padding: 92px 0 56px; min-height: 60svh; }
    /* N-23: the hero source is 16:9 but the mobile hero box is ~0.48 (measured
       810px tall on a 390px viewport), so object-fit:cover scales the image to
       1440px wide and shows only ~27% of it. Pin the image to a shorter band
       and fade it into the page background; that roughly doubles the visible
       fraction and stops the crop reading as "chopped off".
       A mask (not ::after) is used so the light theme's ::after override
       cannot cancel the fade. Portrait hero sources remain the real fix. */
    .hero-bg {
      height: 62%;
      bottom: auto;
      -webkit-mask-image: linear-gradient(to bottom, #000 0%, #000 58%, transparent 100%);
      mask-image: linear-gradient(to bottom, #000 0%, #000 58%, transparent 100%);
    }
  }
  .hero-field-glow {
    position: absolute; inset: 0;
    background:
      radial-gradient(ellipse 80% 50% at 50% 60%, rgba(0, 119, 237, 0.06) 0%, transparent 70%),
      radial-gradient(ellipse 40% 30% at 30% 70%, rgba(0, 119, 237, 0.04) 0%, transparent 60%),
      radial-gradient(ellipse 40% 30% at 70% 70%, rgba(0, 119, 237, 0.04) 0%, transparent 60%);
    pointer-events: none;
    z-index: 0;
  }
  .hero-field-lines {
    position: absolute;
    bottom: 0; left: 50%;
    transform: translateX(-50%);
    width: 90%;
    max-width: 1100px;
    height: 45%;
    border: 1px solid rgba(0, 119, 237, 0.06);
    border-top: 2px solid rgba(0, 119, 237, 0.12);
    border-radius: 50% 50% 0 0 / 20% 20% 0 0;
    pointer-events: none;
    z-index: 0;
  }
  .hero-field-lines::before {
    content: '';
    position: absolute;
    top: 50%;
    left: 10%; right: 10%;
    height: 1px;
    background: rgba(0, 119, 237, 0.08);
  }
  .hero-field-lines::after {
    content: '';
    position: absolute;
    top: 30%;
    left: 50%;
    transform: translateX(-50%);
    width: 30%;
    height: 40%;
    border: 1px solid rgba(0, 119, 237, 0.06);
    border-radius: 50%;
  }

  /* Hide decorative overlays so the hero background image is fully visible */
  .hero-grid,
  .hero-noise,
  .hero-field-glow,
  .hero-field-lines,
  .hero-corner-marks,
  .hero-field-lines::before,
  .hero-field-lines::after,
  .hero-corner-marks::before,
  .hero-corner-marks::after {
    display: none !important;
  }

  .hero-content {
    position: relative;
    z-index: 2;
    text-align: center;
    max-width: 900px;
    margin: 0 auto;
  }
  .hero-meta {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 24px;
    font-family: var(--ff-mono);
    font-size: 11px;
    color: var(--ink-mute);
    letter-spacing: 0.12em;
    text-transform: uppercase;
    margin-bottom: 40px;
    flex-wrap: wrap;
  }
  .hero-meta .dot {
    display: inline-block;
    width: 6px; height: 6px;
    background: var(--accent);
    border-radius: 50%;
  }
  .hero-meta .divider {
    flex: 0 0 24px;
    height: 1px;
    background: var(--line-strong);
  }

  .hero-title {
    font-family: var(--ff-display);
    font-size: var(--fs-hero-title);
    font-weight: 500;
    line-height: 0.95;
    letter-spacing: -0.04em;
    color: var(--ink);
    margin-bottom: 40px;
  }
  .hero-title .line { display: block; }
  .hero-title .line.accent {
    background: linear-gradient(90deg, var(--accent) 0%, #4D9BFF 100%);
    -webkit-background-clip: text;
    background-clip: text;
    -webkit-text-fill-color: transparent;
    font-weight: 600;
  }
  .hero-title .bracket {
    color: var(--accent);
    font-weight: 400;
  }

  /* Text shadow for readability over any hero background image */
  .hero-title,
  .hero-lede,
  .hero-meta,
  .hero-stat-label,
  .hero-stat-num-sub {
    text-shadow: 0 2px 8px rgba(0, 0, 0, 0.35), 0 1px 2px rgba(0, 0, 0, 0.5);
  }
  [data-theme="light"] .hero-title,
  [data-theme="light"] .hero-lede,
  [data-theme="light"] .hero-meta,
  [data-theme="light"] .hero-stat-label,
  [data-theme="light"] .hero-stat-num-sub {
    text-shadow: 0 1px 3px rgba(255, 255, 255, 0.7), 0 1px 1px rgba(255, 255, 255, 0.9);
  }

  .hero-lede {
    font-size: var(--fs-hero-subtitle);
    line-height: 1.7;
    color: var(--ink-soft);
    max-width: 620px;
    margin: 0 auto 40px;
    font-weight: 400;
  }

  .hero-actions {
    display: flex;
    gap: 16px;
    flex-wrap: wrap;
    justify-content: center;
    margin-bottom: 80px;
    align-items: center;
  }

  .btn-primary {
    display: inline-flex;
    align-items: center;
    gap: 10px;
    font-family: var(--ff-mono);
    font-size: 12.5px;
    font-weight: 500;
    padding: 18px 28px;
    background: var(--accent);
    color: #fff;
    letter-spacing: 0.08em;
    text-transform: uppercase;
    transition: all 0.2s;
  }
  .btn-primary:hover {
    background: #0088FF;
    transform: translateY(-1px);
    box-shadow: 0 16px 32px -16px rgba(0, 119, 237, 0.5);
  }
  .btn-primary::after {
    content: '\2192';
    transition: transform 0.2s;
  }
  .btn-primary:hover::after { transform: translateX(3px); }

  .btn-ghost {
    display: inline-flex;
    align-items: center;
    gap: 10px;
    font-family: var(--ff-mono);
    font-size: 12.5px;
    font-weight: 500;
    padding: 18px 24px;
    color: var(--ink);
    letter-spacing: 0.08em;
    text-transform: uppercase;
    border: 1px solid var(--line-strong);
    transition: all 0.2s;
  }
  .btn-ghost:hover { border-color: var(--ink); }

  .hero-stats {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 0;
    max-width: 700px;
    margin: 0 auto;
    border-top: 1px solid var(--line);
    border-left: 1px solid var(--line);
  }
  @media (min-width: 768px) {
    .hero-stats { grid-template-columns: repeat(4, 1fr); }
  }
  .hero-stat {
    padding: 28px 16px 16px;
    display: flex;
    flex-direction: column;
    gap: 8px;
    border-right: 1px solid var(--line);
    border-bottom: 1px solid var(--line);
  }
  .hero-stat-num {
    font-family: var(--ff-display);
    font-size: clamp(32px, 5vw, 56px);
    font-weight: 700;
    letter-spacing: -0.07em;
    line-height: 0.92;
    background: linear-gradient(135deg, #0077ED 0%, #4D9BFF 50%, #00D4FF 100%);
    -webkit-background-clip: text;
    background-clip: text;
    -webkit-text-fill-color: transparent;
    filter: drop-shadow(0 0 16px rgba(0, 119, 237, 0.45));
  }
  .hero-stat-num .unit {
    font-size: 0.4em;
    font-weight: 600;
    margin-left: 2px;
    letter-spacing: -0.03em;
    background: linear-gradient(135deg, #4D9BFF 0%, #00D4FF 100%);
    -webkit-background-clip: text;
    background-clip: text;
    -webkit-text-fill-color: transparent;
    filter: none;
  }
  .hero-stat-label {
    font-family: var(--ff-mono);
    font-size: 11px;
    color: var(--ink-mute);
    letter-spacing: 0.16em;
    text-transform: uppercase;
    font-weight: 500;
  }
  .hero-stat--warranty { gap: 2px; }
  .hero-stat-num-sub {
    font-family: var(--ff-mono);
    font-size: 12px;
    color: var(--ink-mute);
    letter-spacing: 0.1em;
    text-transform: lowercase;
    font-weight: 500;
  }

  /* ============ SECTION GENERIC ============ */
  section { position: relative; padding: 80px 0; }
  @media (min-width: 768px) { section { padding: 120px 0; } }
  @media (min-width: 1200px) { section { padding: 140px 0; } } /* F7: 1024→1200，断点收敛 3 档 */
  .section-label {
    font-family: var(--ff-mono);
    font-size: 11px;
    color: var(--ink-mute);
    letter-spacing: 0.28em;
    text-transform: uppercase;
    margin-bottom: 32px;
    display: inline-flex;
    align-items: center;
    gap: 16px;
  }
  .section-label .num {
    color: var(--accent);
    font-weight: 600;
  }
  .section-label::before {
    content: '';
    width: 40px;
    height: 1px;
    background: var(--line-strong);
  }
  .section-title {
    font-family: var(--ff-display);
    font-size: var(--fs-section-title);
    font-weight: 500;
    line-height: 1.02;
    letter-spacing: -0.04em;
    color: var(--ink);
    max-width: 1000px;
    margin-bottom: 24px;
  }
  .section-body {
    font-size: var(--fs-body);
    line-height: 1.7;
    color: var(--ink-soft);
    max-width: 560px;
  }

  /* ============ PAGE HERO (sub-pages) ============ */
  .page-hero {
    background: var(--bg);
    border-bottom: 1px solid var(--line);
  }

  /* ============ PRODUCTS ============ */
  .products-grid {
    display: grid;
    grid-template-columns: 1fr;
    gap: 0;
    margin-top: 32px;
    border-top: 1px solid var(--line);
    border-left: 1px solid var(--line);
  }
  @media (min-width: 768px) { .products-grid { grid-template-columns: repeat(2, 1fr); margin-top: 40px; } }
  @media (min-width: 1200px) { .products-grid { grid-template-columns: repeat(3, 1fr); margin-top: 48px; } } /* F7: 1024→1200 */
  .product-card {
    background: transparent;
    border-right: 1px solid var(--line);
    border-bottom: 1px solid var(--line);
    padding: 5px 14px 16px;
    transition: background 0.3s, transform 0.3s, box-shadow 0.3s;
    position: relative;
    min-height: auto;
    min-width: 0;
    display: flex;
    flex-direction: column;
  }
  @media (min-width: 768px) { .product-card { padding: 5px 20px 20px; } }
  .product-card:hover {
    background: var(--bg-soft);
    transform: translateY(-8px);
    box-shadow: 0 20px 40px -20px rgba(0, 0, 0, 0.4);
  }
  .product-card:hover .product-card-img img {
    transform: scale(1.06);
  }
  .product-card-top {
    display: flex;
    justify-content: space-between;
    align-items: baseline;
    margin-bottom: 2px;
    font-family: var(--ff-mono);
    font-size: 11px;
    color: var(--ink-mute);
    letter-spacing: 0.12em;
    text-transform: uppercase;
  }
  .product-card-top .index { color: var(--accent); font-weight: 500; }
  .product-card-img {
    display: flex;
    align-items: center;
    justify-content: center;
    margin-bottom: 2px;
    aspect-ratio: 4 / 3;
    overflow: hidden;
  }
  .product-card-img img {
    width: 100%;
    height: 100%;
    object-fit: contain;
    transition: transform 0.4s ease;
    filter: drop-shadow(0 4px 12px rgba(0,0,0,0.15));
  }
  .product-card-img img.m-series-img {
    object-fit: contain;
    object-position: center;
  }
  .product-card-title {
    font-family: var(--ff-display);
    font-size: var(--fs-card-title);
    font-weight: 500;
    color: var(--ink);
    letter-spacing: -0.02em;
    margin-bottom: 4px;
    line-height: 1.2;
  }
  .product-card-desc {
    font-size: var(--fs-card-desc);
    line-height: 1.6;
    color: var(--ink-mute);
    margin-bottom: 8px;
    flex: 0 0 auto;
  }
  .product-card-specs {
    display: flex;
    gap: 0;
    border-top: 1px solid var(--line);
    padding-top: 8px;
    margin-top: auto;
  }
  .product-spec {
    flex: 1;
    padding-right: 12px;
    border-right: 1px solid var(--line);
  }
  .product-spec:last-child { border-right: none; padding-right: 0; }
  .product-spec-value {
    font-family: var(--ff-display);
    font-size: clamp(16px, 1.5vw, 20px);
    font-weight: 500;
    color: var(--ink);
    letter-spacing: -0.02em;
    line-height: 1;
  }
  .product-spec-label {
    display: block;
    font-family: var(--ff-mono);
    font-size: 10px;
    color: var(--ink-subtle);
    letter-spacing: 0.12em;
    text-transform: uppercase;
    margin-top: 6px;
  }

  /* ============ PROJECTS ============ */
  .projects-grid {
    display: flex;
    flex-direction: column;
    gap: 16px;
    margin-top: 12px;
  }
  @media (min-width: 768px) { .projects-grid { gap: 16px; margin-top: 12px; } }
  @media (min-width: 1200px) { .projects-grid { gap: 16px; margin-top: 12px; } } /* F7: 1024→1200 */
  .project-card {
    background: var(--bg-soft);
    border: 1px solid var(--line);
    border-radius: 12px;
    overflow: hidden;
    transition: transform 0.3s, box-shadow 0.3s;
    display: flex;
    flex-direction: column;
    height: auto;
  }
  @media (min-width: 768px) {
    .project-card {
      flex-direction: row;
      align-items: center;
      height: 200px;
    }
  }
  .project-card:hover {
    transform: translateY(-4px);
    box-shadow: 0 20px 40px -20px rgba(0, 0, 0, 0.4);
  }
  .project-card-img {
    position: relative;
    width: 100%;
    height: 180px;
    overflow: hidden;
    background: var(--bg-soft);
    flex-shrink: 0;
    border-radius: 8px;
    margin: 12px 12px 0;
  }
  @media (min-width: 768px) {
    .project-card-img {
      width: 45%;
      height: 180px;
      margin: 0 0 0 12px;
      align-self: center;
    }
  }
  /* N-18: 移动端 <768px 时 .project-card 是 flex-direction:column，
     此时 `width:100%` 会与左右各 12px 的 margin 叠加 → 实际宽度 = 容器内容宽 + 24px，
     右侧超出 12px 被卡片的 overflow:hidden 静默裁掉（图片被切、左右留白不对称）。
     flex column 下改 width:auto 即可由 stretch 自动填满并扣掉 margin。
     桌面档已被上面的 45% 覆盖，此规则不影响 ≥768px 渲染。 */
  @media (max-width: 767px) {
    .project-card-img { width: auto; }
  }
  .project-card-img img {
    width: 100%;
    height: 100%;
    object-fit: cover;
    object-position: center center;
    border-radius: 8px;
  }
  .project-card-img-placeholder {
    position: absolute;
    inset: 0;
    width: 100%;
    height: 100%;
  }
  .project-card-img-placeholder.stadium {
    background: linear-gradient(135deg, #0a1628 0%, #0d2040 30%, #142850 60%, #0a1830 100%);
  }
  .project-card-img-placeholder.stadium::before {
    content: '';
    position: absolute;
    inset: 0;
    background:
      radial-gradient(ellipse 60% 40% at 50% 40%, rgba(0, 119, 237, 0.15) 0%, transparent 70%),
      radial-gradient(ellipse 30% 20% at 20% 60%, rgba(77, 155, 255, 0.08) 0%, transparent 60%),
      radial-gradient(ellipse 30% 20% at 80% 60%, rgba(77, 155, 255, 0.08) 0%, transparent 60%);
  }
  .project-card-img-placeholder.stadium::after {
    content: '';
    position: absolute;
    bottom: 0; left: 10%; right: 10%;
    height: 40%;
    border-top: 1px solid rgba(0, 119, 237, 0.12);
    border-radius: 40% 40% 0 0;
  }
  .project-card-img-placeholder.arena {
    background: linear-gradient(135deg, #0d1420 0%, #101a2e 30%, #0e1830 60%, #0a1020 100%);
  }
  .project-card-img-placeholder.arena::before {
    content: '';
    position: absolute;
    inset: 0;
    background:
      radial-gradient(ellipse 50% 50% at 50% 50%, rgba(0, 119, 237, 0.12) 0%, transparent 60%),
      radial-gradient(circle at 50% 50%, rgba(77, 155, 255, 0.06) 0%, transparent 40%);
  }
  .project-card-img-placeholder.arena::after {
    content: '';
    position: absolute;
    top: 50%; left: 50%;
    transform: translate(-50%, -50%);
    width: 60%; height: 50%;
    border: 1px solid rgba(0, 119, 237, 0.08);
    border-radius: 50%;
  }
  .project-card-img-placeholder .field-label {
    position: absolute;
    bottom: 16px; left: 16px;
    font-family: var(--ff-mono);
    font-size: 10px;
    color: rgba(255, 255, 255, 0.3);
    letter-spacing: 0.15em;
    text-transform: uppercase;
  }
  .project-card-body {
    padding: 16px 20px;
    min-width: 0;
    overflow: hidden;
    display: flex;
    flex-direction: column;
    justify-content: center;
  }
  @media (min-width: 768px) { .project-card-body { padding: 18px 22px; } }
  .project-card-location {
    font-family: var(--ff-mono);
    font-size: 11px;
    color: var(--accent);
    letter-spacing: 0.12em;
    text-transform: uppercase;
    margin-bottom: 6px;
  }
  .project-card-title {
    font-family: var(--ff-display);
    font-size: var(--fs-card-title);
    font-weight: 500;
    color: var(--ink);
    letter-spacing: -0.02em;
    margin-bottom: 8px;
    line-height: 1.25;
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
  }
  /* F10: 移动端允许换行（桌面卡片窄保留 ellipsis；移动端全宽本有空间） */
  @media (max-width: 767px) {
    .project-card-title { white-space: normal; overflow: visible; }
  }
  .project-card-desc {
    font-size: var(--fs-card-desc);
    line-height: 1.55;
    color: var(--ink-mute);
    margin-bottom: 0;
    display: -webkit-box;
    -webkit-line-clamp: 2;
    -webkit-box-orient: vertical;
    overflow: hidden;
  }
  .project-card-results {
    display: none;
  }
  .project-card-quote {
    border-left: 2px solid var(--accent);
    padding-left: 16px;
    font-size: 14px;
    line-height: 1.65;
    color: var(--ink-soft);
    font-style: italic;
    margin-bottom: 8px;
  }
  .project-card-attribution {
    font-family: var(--ff-mono);
    font-size: 11px;
    color: var(--ink-subtle);
    letter-spacing: 0.05em;
  }

  /* ============ ABOUT / WHY SOLARONE ============ */
  .about-section {
    background: var(--bg-soft);
    border-top: 1px solid var(--line);
    border-bottom: 1px solid var(--line);
  }
  .about-content {
    max-width: 720px;
  }
  .about-text {
    font-size: clamp(15px, 0.9375rem + 0.125vw, 16px);
    line-height: 1.8;
    color: var(--ink-soft);
    margin-bottom: 64px;
  }
  @media (min-width: 768px) { .about-text { margin-bottom: 80px; } }
  .about-stats {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 0;
    border-top: 1px solid var(--line);
    border-left: 1px solid var(--line);
  }
  @media (min-width: 768px) { .about-stats { grid-template-columns: repeat(4, 1fr); } }
  .about-stat {
    padding: 32px 20px;
    border-right: 1px solid var(--line);
    border-bottom: 1px solid var(--line);
    display: flex;
    flex-direction: column;
    gap: 8px;
  }
  @media (min-width: 768px) { .about-stat { padding: 40px 24px; } }
  .about-stat-num {
    font-family: var(--ff-display);
    font-size: clamp(36px, 5vw, 56px);
    font-weight: 700;
    letter-spacing: -0.06em;
    line-height: 0.92;
    color: var(--ink);
  }
  .about-stat-num .plus { color: var(--accent); }
  .about-stat-num .unit {
    font-size: 0.45em;
    font-weight: 500;
    letter-spacing: -0.02em;
  }
  .about-stat-label {
    font-family: var(--ff-mono);
    font-size: 11px;
    color: var(--ink-mute);
    letter-spacing: 0.16em;
    text-transform: uppercase;
    font-weight: 500;
  }

  /* ============ CONTACT ============ */
  .contact-grid {
    display: grid;
    grid-template-columns: 1fr;
    gap: 48px;
    margin-top: 48px;
  }
  @media (min-width: 768px) { .contact-grid { grid-template-columns: 1fr 1fr; gap: 64px; margin-top: 64px; } }
  @media (min-width: 1200px) { .contact-grid { margin-top: 80px; } } /* F7: 1024→1200 */

  .contact-info-list {
    list-style: none;
    display: flex;
    flex-direction: column;
    gap: 0;
    margin-bottom: 32px;
  }
  .contact-info-item {
    display: flex;
    align-items: flex-start;
    gap: 20px;
    padding: 24px 0;
    border-bottom: 1px solid var(--line);
  }
  .contact-info-icon {
    width: 44px; height: 44px;
    display: flex; align-items: center; justify-content: center;
    border: 1px solid var(--line-strong);
    flex-shrink: 0;
    color: var(--accent);
  }
  .contact-info-icon svg { width: 20px; height: 20px; }
  .contact-info-detail {
    display: flex;
    flex-direction: column;
    gap: 4px;
  }
  .contact-info-label {
    font-family: var(--ff-mono);
    font-size: 10px;
    color: var(--ink-subtle);
    letter-spacing: 0.18em;
    text-transform: uppercase;
  }
  .contact-info-value {
    font-size: 15px;
    color: var(--ink);
    font-weight: 500;
    letter-spacing: -0.01em;
  }
  .contact-info-value a {
    color: inherit;
    transition: color 0.2s;
  }
  .contact-info-value a:hover { color: var(--accent); }

  .contact-whatsapp {
    display: inline-flex;
    align-items: center;
    gap: 10px;
    font-family: var(--ff-mono);
    font-size: 12.5px;
    font-weight: 500;
    padding: 14px 24px;
    background: #25D366;
    color: #fff;
    letter-spacing: 0.06em;
    text-transform: uppercase;
    transition: all 0.2s;
    margin-top: 16px;
  }
  .contact-whatsapp:hover {
    background: #20BD5A;
    transform: translateY(-1px);
    box-shadow: 0 12px 24px -12px rgba(37, 211, 102, 0.5);
  }
  .contact-whatsapp svg { width: 18px; height: 18px; }

  /* Contact form */
  .contact-form { display: flex; flex-direction: column; gap: 20px; }
  .form-group { display: flex; flex-direction: column; gap: 6px; }
  .form-group label {
    font-family: var(--ff-mono);
    font-size: 10px;
    color: var(--ink-subtle);
    letter-spacing: 0.18em;
    text-transform: uppercase;
  }
  .form-group input,
  .form-group textarea {
    width: 100%;
    padding: 14px 16px;
    background: var(--bg-soft);
    border: 1px solid var(--line);
    border-radius: 8px;
    color: var(--ink);
    font-family: var(--ff-body);
    font-size: 15px;
    outline: none;
    transition: border-color 0.2s, box-shadow 0.2s;
  }
  .form-group input::placeholder,
  .form-group textarea::placeholder {
    color: var(--ink-subtle);
  }
  .form-group input:focus,
  .form-group textarea:focus {
    border-color: var(--accent);
    box-shadow: 0 0 0 3px var(--accent-glow);
  }
  .form-group textarea {
    resize: vertical;
    min-height: 120px;
  }
  /* N-1: font-size < 16px makes iOS Safari auto-zoom the page when an
     input is focused (and it never zooms back out). Placed after the base
     rule so the cascade keeps this as the effective value. */
  .form-group input,
  .form-group textarea { font-size: 16px; }
  .form-submit {
    align-self: flex-start;
  }
  .form-submit .btn-primary {
    border-radius: 8px;
  }
  .form-whatsapp-row {
    display: flex;
    align-items: center;
    gap: 16px;
    margin-top: 8px;
  }

  /* ============ FOOTER ============ */
  footer {
    background: var(--bg);
    border-top: 1px solid var(--line);
    padding: 28px 0 16px;
  }
  @media (min-width: 768px) { footer { padding: 32px 0 16px; } }
  .footer-grid {
    display: grid;
    grid-template-columns: 1fr;
    gap: 20px;
    margin-bottom: 16px;
  }
  @media (min-width: 768px) { .footer-grid { grid-template-columns: 1fr 1fr; gap: 20px; } }
  @media (min-width: 1200px) { .footer-grid { grid-template-columns: 1.6fr 1fr 1fr 1fr; gap: 24px; margin-bottom: 20px; } } /* F7: 1024→1200 */
  .footer-brand-name {
    font-family: var(--ff-display);
    font-size: clamp(22px, 2vw, 28px);
    font-weight: 500;
    color: var(--ink);
    letter-spacing: -0.03em;
    margin-bottom: 6px;
  }
  .footer-brand-text {
    font-size: 12px;
    line-height: 1.4;
    color: var(--ink-mute);
    max-width: 320px;
  }
  .footer-col-label {
    font-family: var(--ff-mono);
    font-size: 9px;
    letter-spacing: 0.12em;
    text-transform: uppercase;
    color: var(--ink-subtle);
    margin-bottom: 6px;
    font-weight: 500;
  }
  .footer-list { list-style: none; display: flex; flex-direction: column; gap: 4px; }
  .footer-list a {
    font-size: 14px;
    color: var(--ink-mute);
    transition: color 0.2s;
  }
  .footer-list a:hover { color: var(--accent); }
  .footer-social {
    display: flex;
    gap: 12px;
    align-items: center;
    flex-wrap: wrap;
  }
  .footer-social a {
    width: 40px; height: 40px;
    display: flex; align-items: center; justify-content: center;
    border: 1px solid var(--line-strong);
    transition: border-color 0.2s, color 0.2s;
    color: var(--ink);
  }
  .footer-social a:hover {
    border-color: var(--accent);
    color: var(--accent);
  }
  .footer-social a svg { width: 18px; height: 18px; }

  .footer-bottom {
    padding-top: 10px;
    border-top: 1px solid var(--line);
    display: flex;
    justify-content: space-between;
    align-items: center;
    gap: 16px;
    flex-wrap: wrap;
  }
  @media (min-width: 768px) { .footer-bottom { padding-top: 10px; } }
  .footer-copy {
    font-family: var(--ff-mono);
    font-size: 11px;
    color: var(--ink-subtle);
    letter-spacing: 0.05em;
  }
  .footer-legal {
    display: flex;
    gap: 24px;
  }
  .footer-legal a {
    font-family: var(--ff-mono);
    font-size: 11px;
    color: var(--ink-subtle);
    letter-spacing: 0.05em;
    transition: color 0.2s;
  }
  .footer-legal a:hover { color: var(--accent); }

  /* ============ SIDEBAR NAV (shared across sidebar pages) ============ */
  /* Typography hierarchy:
     - parent:    display font, uppercase, folder-like headers
     - child:     body font, readable series links
     - grandchild: body font, slightly smaller subseries links
     - mono is reserved for micro-labels (header, view-all) only. */

  .sidebar-nav {
    padding: 18px 14px;
    background: var(--bg-soft);
    border: 1px solid var(--line);
    border-radius: 14px;
  }
  [data-theme="light"] .sidebar-nav {
    background: var(--bg-raised);
    box-shadow: 0 1px 3px rgba(0,0,0,0.04);
  }
  .sidebar-nav-header {
    font-family: var(--ff-mono);
    font-size: 11px;
    font-weight: 600;
    letter-spacing: 0.14em;
    text-transform: uppercase;
    color: var(--accent);
    margin-bottom: 18px;
    padding-bottom: 12px;
    border-bottom: 1px solid var(--line);
  }
  .sidebar-nav-list {
    display: flex;
    flex-direction: column;
    gap: 14px;
  }

  /* Level 1 — category headers */
  .sidebar-nav-parent {
    display: flex;
    align-items: center;
    padding: 5px 10px;
    font-family: var(--ff-display);
    font-size: 0.82rem;
    font-weight: 600;
    letter-spacing: 0.02em;
    text-transform: uppercase;
    line-height: 1.3;
    word-break: break-word;
    color: var(--ink);
    background: rgba(255, 255, 255, 0.04);
    border: 1px solid var(--line);
    border-radius: 8px;
    user-select: none;
    transition: background 0.2s, color 0.2s, border-color 0.2s, box-shadow 0.2s;
  }
  .sidebar-nav-parent:hover,
  .sidebar-nav-parent.active {
    color: var(--accent);
    background: var(--accent-soft);
    border-color: var(--accent);
    box-shadow: 0 0 0 3px var(--accent-glow);
  }
  [data-theme="light"] .sidebar-nav-parent {
    background: rgba(0, 0, 0, 0.02);
    border-color: rgba(0, 0, 0, 0.06);
  }
  [data-theme="light"] .sidebar-nav-parent:hover,
  [data-theme="light"] .sidebar-nav-parent.active {
    background: var(--accent-soft);
    border-color: var(--accent);
  }

  /* Level 2 — series / sport links */
  .sidebar-nav-children {
    padding: 6px 0 2px 10px;
    display: flex;
    flex-direction: column;
    gap: 1px;
  }
  .sidebar-nav-child {
    display: flex;
    align-items: center;
    gap: 10px;
    padding: 4px 10px 4px 22px;
    font-family: var(--ff-body);
    font-size: 0.94rem;
    font-weight: 500;
    line-height: 1.4;
    color: var(--ink-mute);
    text-decoration: none;
    border-radius: 6px;
    transition: color 0.2s, background 0.2s;
    position: relative;
  }
  .sidebar-nav-child::before {
    content: '';
    position: absolute;
    left: 8px;
    top: 50%;
    transform: translateY(-50%);
    width: 0;
    height: 55%;
    background: var(--accent);
    border-radius: 2px;
    transition: width 0.2s;
  }
  .sidebar-nav-child::after {
    content: '';
    width: 0;
    height: 1.5px;
    background: var(--ink-subtle);
    flex-shrink: 0;
    border-radius: 1px;
    transition: background 0.2s, width 0.2s;
  }
  .sidebar-nav-child:hover {
    color: var(--accent);
    background: rgba(255, 255, 255, 0.04);
  }
  [data-theme="light"] .sidebar-nav-child:hover {
    background: rgba(0, 0, 0, 0.03);
  }
  .sidebar-nav-child:hover::before,
  .sidebar-nav-child.active::before {
    width: 3px;
  }
  .sidebar-nav-child:hover::after,
  .sidebar-nav-child.active::after {
    background: var(--accent);
    width: 6px;
  }
  /* Toggle rows already have an arrow; skip the trailing dash */
  .sidebar-nav-child-toggle::after { display: none; }
  .sidebar-nav-child.active {
    color: var(--accent);
    font-weight: 600;
    background: rgba(255, 255, 255, 0.06);
  }
  [data-theme="light"] .sidebar-nav-child.active {
    background: rgba(0, 119, 237, 0.06);
  }

  /* Level 3 — subseries links */
  .sidebar-nav-grandchildren {
    padding: 5px 0 5px 30px;
    display: none;
    position: relative;
  }
  .sidebar-nav-grandchildren::before {
    content: '';
    position: absolute;
    left: 16px;
    top: 6px;
    bottom: 6px;
    width: 1px;
    background: var(--line-strong);
    opacity: 0.5;
  }
  .sidebar-nav-grandchildren.open {
    display: flex;
    flex-direction: column;
    gap: 2px;
  }
  .sidebar-nav-grandchild {
    display: flex;
    align-items: center;
    gap: 8px;
    padding: 4px 10px 4px 20px;
    font-family: var(--ff-body);
    font-size: 0.87rem;
    font-weight: 400;
    line-height: 1.35;
    color: var(--ink-mute);
    text-decoration: none;
    border-radius: 5px;
    transition: color 0.15s, background 0.15s;
    position: relative;
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
  }
  .sidebar-nav-grandchild::before {
    content: '';
    width: 3px;
    height: 3px;
    border-radius: 50%;
    background: var(--ink-subtle);
    flex-shrink: 0;
    transition: background 0.15s, transform 0.15s;
  }
  .sidebar-nav-grandchild:hover {
    color: var(--accent);
    background: rgba(255, 255, 255, 0.04);
  }
  [data-theme="light"] .sidebar-nav-grandchild:hover {
    background: rgba(0, 0, 0, 0.03);
  }
  .sidebar-nav-grandchild:hover::before {
    background: var(--accent);
    transform: scale(1.4);
  }
  .sidebar-nav-grandchild.active {
    color: var(--accent);
    font-weight: 600;
    background: rgba(255, 255, 255, 0.06);
  }
  [data-theme="light"] .sidebar-nav-grandchild.active {
    background: rgba(0, 119, 237, 0.06);
  }
  .sidebar-nav-grandchild.active::before {
    background: var(--accent);
  }

  /* Toggle-able series row (has subseries, e.g. M Series) */
  .sidebar-nav-child-toggle {
    cursor: pointer;
    user-select: none;
  }
  .sidebar-nav-child-toggle .sidebar-nav-child-label {
    flex: 1;
    min-width: 0;
    line-height: 1.3;
    word-break: break-word;
  }
  .sidebar-nav-toggle-arrow {
    flex-shrink: 0;
    font-family: var(--ff-mono);
    font-size: 0.8rem;
    color: var(--ink-subtle);
    transition: transform 0.2s ease, color 0.15s;
    transform: rotate(0deg);
    display: inline-block;
  }
  .sidebar-nav-child-toggle.open .sidebar-nav-toggle-arrow {
    transform: rotate(90deg);
    color: var(--accent);
  }
  .sidebar-nav-child-toggle:hover .sidebar-nav-toggle-arrow {
    color: var(--accent);
  }

  /* View-all link */
  .sidebar-nav-all {
    display: block;
    margin-top: 18px;
    padding-top: 14px;
    border-top: 1px solid var(--line);
    font-family: var(--ff-mono);
    font-size: 11px;
    font-weight: 600;
    letter-spacing: 0.1em;
    text-transform: uppercase;
    color: var(--ink-mute);
    text-decoration: none;
    transition: color 0.2s;
  }
  .sidebar-nav-all:hover,
  .sidebar-nav-all.active {
    color: var(--accent);
  }

  /* Default (desktop) sidebar layout — two-column grid. The inline
     grid-template-columns on older templates is being phased out in
     favor of this CSS-driven approach (fixes 364px overflow on mobile
     where inline styles with high specificity defeated the media
     query !important override). */
  .sidebar-layout {
    display: grid;
    grid-template-columns: 270px 1fr;
    gap: 20px;
    align-items: start;
  }
  /* N-25（grid blowout 根本解）：grid item 的 min-width 默认 auto，会把所在
     轨道顶到内容的 min-content 宽度。产品详情页因此整页撑到 921px（390 视口
     仅可见 390），用户在手机端"只能看到很小的一部分"。
     元凶是 .detail-ordering-table(min-width:900px) 与 .detail-energy-table
     (th white-space:nowrap → 899px)；它们虽被 overflow-x:auto 容器包裹，
     但 min-width:auto 让 blowout 绕过容器一路传导到 html。
     min-width:0 作用在 grid item 上，不依赖轨道写法，**不会被模板内联的
     `1fr !important` 反杀**（N-21 的 minmax(0,1fr) 就被 10 处内联覆盖了）。 */
  .sidebar-layout > *,
  .about-story-grid > *,
  .contact-grid > * {
    min-width: 0;
  }


  @media (max-width: 767px) {
    /* N-21: 必须是 minmax(0, 1fr) 而不是 1fr。
       `1fr` 等价于 minmax(auto, 1fr)，其最小值取轨道内容的 min-content；
       .project-card 的 min-content 约 347px，在 320/360 档会把轨道顶到
       346.53px（容器仅 288/328px）→ 整页横向溢出 44px，被 body
       overflow-x:hidden 静默裁切（与 P0-1 同一失效模式）。
       minmax(0, 1fr) 允许轨道收缩到 0，是 grid blowout 的标准解法。 */
    .sidebar-layout {
      grid-template-columns: minmax(0, 1fr) !important;
    }
    .sidebar-nav {
      position: relative !important;
      top: auto !important;
    }
  }
  /* F7: 768–1199 平板档保持窄侧栏；≥1200 用桌面默认 270px。3 档：≤767 / 768–1199 / ≥1200 */
  @media (min-width: 768px) and (max-width: 1199px) {
    .products-page-with-sidebar .sidebar-layout {
      grid-template-columns: 260px 1fr !important;
    }
  }

  /* ============ SIDEBAR COLLAPSE (F4' — checkbox hack, D2/D3) ============ */
  /* Desktop/tablet: toggle hidden, tree always expanded. At the ≤767px
     (F7: 原 900 收敛) sidebar-layout single-column breakpoint the label
     appears and the tree collapses unless the box is checked. "Expanded"
     is the HTML default — collapsing is the enhancement, so no-JS users
     never lose the category navigation (§8.2). */
  .sidebar-toggle-input,
  .sidebar-toggle-label { display: none; }
  @media (max-width: 767px) {
    .sidebar-toggle-input {
      position: absolute;
      width: 1px;
      height: 1px;
      opacity: 0;
      pointer-events: none;
    }
    .sidebar-toggle-input:focus-visible ~ .sidebar-toggle-label {
      outline: 2px solid var(--accent);
      outline-offset: 2px;
    }
    .sidebar-toggle-label {
      display: flex;
      align-items: center;
      min-height: 44px;
      padding: 8px 0;
      cursor: pointer;
      font-family: var(--ff-mono);
      font-size: 12px;
      letter-spacing: 0.15em;
      text-transform: uppercase;
      color: var(--accent);
    }
    .sidebar-toggle-label::after {
      content: "";
      width: 8px;
      height: 8px;
      margin-left: auto;
      border-right: 2px solid currentColor;
      border-bottom: 2px solid currentColor;
      transform: rotate(45deg);
      transition: transform 0.2s;
    }
    .sidebar-toggle-input:checked ~ .sidebar-toggle-label::after {
      transform: rotate(225deg);
    }
    .sidebar-toggle-input:not(:checked) ~ .sidebar-nav { display: none; }
  }

  /* ============ TABLE HORIZONTAL-SCROLL HINT (N-16) ============ */
  /* 全局滑动提示：任意可横滑表格容器（如 .detail-ordering-table-wrap）在其上方
     放 <p class="scroll-hint"> 即有统一样式；display 由各页在 ≤767px 显形。 */
  .scroll-hint {
    display: none;
    margin: 10px 0 0;
    font-family: var(--ff-mono);
    font-size: 11px;
    letter-spacing: 0.08em;
    text-transform: uppercase;
    color: var(--ink-mute);
  }

  /* ============ REVEAL ============ */
  /* F11: 仅在有 JS 时（html.js 前缀）初始隐藏；无 JS 时这些规则不命中 → 内容默认可见（P1-9 根治） */
  html.js .reveal {
    opacity: 0;
    transform: translateY(30px);
    transition: opacity 0.9s ease, transform 0.9s ease;
  }
  html.js .reveal.is-visible {
    opacity: 1;
    transform: translateY(0);
  }
  @media (prefers-reduced-motion: reduce) {
    html { scroll-behavior: auto; } /* N-8: CSS side; JS anchor scrolling checks the same media query */
    html.js .reveal { opacity: 1; transform: none; transition: none; }
    .hero-field-lines::before,
    .hero-field-lines::after { animation: none; }
    /* N-24: kill the cross-fade only — the rotation itself must keep running */
    .hero-slide { transition: none; }
  }

  /* ============ MOBILE TYPOGRAPHY CLAMP (F5' / D1) ============ */
  /* Mobile-only re-derivation of the two public title vars. The admin value
     always stays the upper bound (min), and the fluid term keeps a rem base
     so the browser font-size setting is respected (WCAG 1.4.4). The desktop
     rendering path is untouched (plain aliases in :root above). */
  @media (max-width: 767px) {
    :root {
      --fs-hero-title:    min(var(--fs-hero-title-admin),    max(30px, calc(1rem + 4vw)));
      --fs-section-title: min(var(--fs-section-title-admin), max(22px, calc(0.85rem + 2.4vw)));
    }
  }

  /* ============ ABOUT PAGE ============ */
  .about-story-grid {
    display: grid;
    grid-template-columns: 1.35fr 1fr;
    gap: 64px;
    align-items: center;
  }
  @media (max-width: 767px) {
    .about-story-grid { grid-template-columns: 1fr; }
  }

  .section-accent-label {
    font-family: var(--ff-mono);
    font-size: 11px;
    letter-spacing: 0.15em;
    text-transform: uppercase;
    color: var(--accent);
    display: block;
    margin-bottom: 20px;
  }

  .about-story-stats {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 32px;
    max-width: 900px;
    margin: 48px auto 0;
  }
  @media (max-width: 767px) {
    .about-story-stats { grid-template-columns: repeat(2, 1fr); }
  }

  .about-stat-circle-wrap {
    text-align: center;
  }

  .about-stat-circle {
    width: 100px;
    height: 100px;
    margin: 0 auto 16px;
    border-radius: 50%;
    border: 2px solid var(--accent);
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
  }

  .about-stat-circle-value {
    font-family: var(--ff-display);
    font-size: 1.6rem;
    font-weight: 700;
    color: var(--accent);
    line-height: 1;
  }

  .about-stat-circle-unit {
    font-family: var(--ff-mono);
    font-size: 9px;
    letter-spacing: 0.1em;
    text-transform: uppercase;
    color: var(--ink-mute);
    margin-top: 4px;
  }

  .about-stat-circle-label {
    font-size: 0.85rem;
    color: var(--ink-mute);
  }

  .about-tech-header {
    text-align: center;
    max-width: 800px;
    margin: 0 auto 40px;
  }

  .about-tech-pillars {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 32px;
    max-width: 1100px;
    margin: 0 auto;
  }
  @media (max-width: 767px) {
    .about-tech-pillars { grid-template-columns: 1fr; }
  }

  .about-pillar {
    background: var(--bg-soft);
    border: 1px solid var(--line);
    border-radius: 16px;
    padding: 48px 40px;
    text-align: center;
    position: relative;
    overflow: hidden;
  }

  .about-pillar-accent {
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 3px;
    background: linear-gradient(90deg, var(--accent), var(--accent-deep));
  }

  .about-pillar-icon {
    max-height: 180px;
    max-width: 90%;
    object-fit: contain;
  }

  .about-optics-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 24px;
    max-width: 1100px;
    margin: 0 auto;
  }
  @media (max-width: 767px) {
    .about-optics-grid { grid-template-columns: 1fr; }
  }

  /* About page — converged from about.html inline <style> (N-13/F12, v1.6) */
  .about-services-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 24px;
    max-width: 1100px;
    margin: 0 auto;
  }
  @media (max-width: 767px) {
    .about-services-grid { grid-template-columns: 1fr; }
  }
  .about-pillar, .about-service-card, .about-optic-card {
    transition: transform 0.3s, box-shadow 0.3s, border-color 0.3s;
  }
  .about-service-card:hover {
    border-color: var(--accent);
    transform: translateY(-3px);
    box-shadow: 0 12px 32px -12px rgba(0, 119, 237, 0.15);
  }
  .about-pillar:hover {
    transform: translateY(-4px);
    box-shadow: 0 20px 40px -20px rgba(0, 119, 237, 0.2);
  }
  .about-optic-card:hover {
    border-color: var(--accent-glow);
    transform: translateY(-2px);
    box-shadow: 0 16px 36px -16px rgba(0, 119, 237, 0.15);
  }

  .about-simple-steps {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 32px;
  }
  @media (max-width: 767px) {
    .about-simple-steps { grid-template-columns: 1fr; }
  }