/* ============================================================
   WinKey 商城样式表
   目标浏览器：Chrome 78+（2019-10）
   兼容策略（只使用 Chrome 78 原生支持的特性）：
   - 布局：CSS Grid（grid 中可安全使用 gap，Chrome 66+）
     Flexbox 仅用于单行内联排布，且【不使用 flex gap】（Chrome 84 才支持），
     间距一律用 margin 实现。
   - 不使用：clamp()/min()/max()（79+）、aspect-ratio（88+）、
     inset 简写（87+）、:is()/:where()/:has()（88+/105+）、
     :focus-visible（86+）、::marker（80+）、accent-color（93+）、
     flex gap（84+）。
   - 需要内核前缀：-webkit-appearance、-webkit-backdrop-filter（双写）、
     ::-webkit-input-placeholder（与 ::placeholder 双写）、
     -webkit-background-clip: text。
   ============================================================ */

/* ---------- 设计变量 ---------- */
:root {
  --bg: #f2f4f9;
  --bg-alt: #e9edf5;
  --surface: #ffffff;
  --surface-2: #f6f8fc;
  --line: #dfe4ee;
  --text: #1b2233;
  --text-2: #5a6478;
  --primary: #0067c0;
  --primary-strong: #005a9e;
  --primary-soft: #e3f0fc;
  --accent: #4cc2ff;
  --danger: #d13438;
  --ok: #0f7b3f;
  --warn-bg: #fff4ce;
  --shadow-1: 0 2px 8px rgba(23, 32, 54, .08);
  --shadow-2: 0 10px 32px rgba(23, 32, 54, .14);
  --shadow-3: 0 18px 56px rgba(23, 32, 54, .22);
  --radius-s: 6px;
  --radius-m: 10px;
  --radius-l: 16px;
  --radius-xl: 22px;
  --ease: cubic-bezier(.22, .61, .36, 1);
  --header-h: 64px;
}

/* 本站固定浅色主题，不提供深色模式 */

/* ---------- 基础 ---------- */
* { box-sizing: border-box; }

/* [hidden] 必须彻底隐藏：作者样式的 display 会覆盖 UA 对 [hidden] 的默认值，
   该规则保证 JS 用 hidden 属性控制显隐的浮层（遮罩/抽屉/徽章）可靠生效 */
[hidden] { display: none !important; }

html { scroll-behavior: smooth; }

body {
  margin: 0;
  min-width: 1160px;   /* 与主容器同宽：窗口 >= 1160 时无横滚、各区块精确居中 */
  font-family: "Segoe UI", "Microsoft YaHei", "PingFang SC", "Hiragino Sans GB", sans-serif;
  font-size: 16px;
  line-height: 1.6;
  color: var(--text);
  background: var(--bg);
  -webkit-font-smoothing: antialiased;
  -webkit-text-size-adjust: 100%;
  transition: background-color .25s var(--ease), color .25s var(--ease);
}

h1, h2, h3, p, ul, ol, figure { margin: 0; }
img, svg { display: block; }
a { color: inherit; text-decoration: none; }
button { font: inherit; color: inherit; cursor: pointer; }
code, kbd {
  font-family: Consolas, "Courier New", monospace;
  font-size: .92em;
  background: var(--primary-soft);
  color: var(--primary-strong);
  border-radius: 4px;
  padding: 1px 6px;
}
kbd { border: 1px solid var(--line); border-bottom-width: 2px; background: var(--surface); }

:focus { outline: none; }   /* 去掉焦点包围框（输入框保留自身边框变色反馈） */

::selection { background: rgba(0, 103, 192, .25); }

.container { width: 100%; max-width: 1160px; margin: 0 auto; padding: 0 24px; }
.container-narrow { max-width: 860px; }

.icon { width: 20px; height: 20px; flex: none; }

/* ---------- 按钮 ---------- */
.btn {
  display: -webkit-flex; display: flex;
  -webkit-align-items: center; align-items: center;
  -webkit-justify-content: center; justify-content: center;
  /* Chrome 78 无 flex gap：.btn 内间距由 .btn .icon { margin-left } 控制 */
  border: 1px solid transparent;
  border-radius: var(--radius-m);
  padding: 10px 20px;
  font-weight: 600;
  letter-spacing: .02em;
  transition: transform .15s var(--ease), box-shadow .2s var(--ease),
              background-color .2s var(--ease), color .2s var(--ease), border-color .2s var(--ease);
  -webkit-user-select: none; user-select: none;
}
.btn .icon { margin-left: 8px; width: 18px; height: 18px; }
.btn:active { transform: scale(.97); }

.btn-primary {
  color: #fff;
  background: linear-gradient(180deg, var(--primary) 0%, var(--primary-strong) 100%);
  box-shadow: var(--shadow-1);
}
.btn-primary:hover { box-shadow: 0 4px 14px rgba(0, 103, 192, .35); }
.btn-primary[disabled] {
  cursor: not-allowed;
  background: var(--line);
  color: var(--text-2);
  box-shadow: none;
}

.btn-ghost {
  color: var(--text);
  background: var(--surface);
  border-color: var(--line);
  box-shadow: var(--shadow-1);
}
.btn-ghost:hover { border-color: var(--primary); color: var(--primary-strong); }

.btn-lg { padding: 13px 28px; font-size: 16px; border-radius: var(--radius-m); }
.btn-block { width: 100%; }

.icon-btn {
  display: -webkit-inline-flex; display: inline-flex;
  -webkit-align-items: center; align-items: center;
  -webkit-justify-content: center; justify-content: center;
  width: 40px; height: 40px;
  border: 1px solid var(--line);
  border-radius: var(--radius-m);
  background: var(--surface);
  color: var(--text);
  transition: border-color .2s var(--ease), color .2s var(--ease), background-color .2s var(--ease);
}
.icon-btn:hover { border-color: var(--primary); color: var(--primary-strong); }

/* ---------- 促销条 ---------- */
.promo-bar {
  display: -webkit-flex; display: flex;
  -webkit-align-items: center; align-items: center;
  -webkit-justify-content: center; justify-content: center;
  padding: 8px 16px;
  font-size: 13px;
  color: #fff;
  background: linear-gradient(90deg, #005a9e, #0067c0 45%, #106ebe);
}
.promo-badge {
  margin-right: 10px;
  padding: 1px 8px;
  font-size: 12px;
  font-weight: 700;
  color: #005a9e;
  background: #fff;
  border-radius: 999px;
}

/* ---------- 页头 ---------- */
.site-header {
  position: sticky;
  top: 0;
  z-index: 100;
  background: rgba(255, 255, 255, .78);
  backdrop-filter: saturate(150%) blur(14px);
  border-bottom: 1px solid var(--line);   /* 分割线常显 */
  transition: background-color .25s var(--ease);
}

.header-inner {
  display: -webkit-flex; display: flex;
  -webkit-align-items: center; align-items: center;
  height: var(--header-h);
}

.brand { display: -webkit-flex; display: flex; -webkit-align-items: center; align-items: center; margin-right: 40px; }
.brand-logo {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 3px;
  width: 30px; height: 30px;
  margin-right: 12px;
  transform: rotate(-4deg);
}
.brand-logo .cell { border-radius: 3px; }
.brand-logo .c1 { background: #f25022; }
.brand-logo .c2 { background: #7fba00; }
.brand-logo .c3 { background: #00a4ef; }
.brand-logo .c4 { background: #ffb900; }

.brand-name { font-size: 20px; font-weight: 700; letter-spacing: .01em; }
.brand-name em { font-style: normal; color: var(--primary); }

.main-nav { display: -webkit-flex; display: flex; -webkit-flex: 1; flex: 1; }
.main-nav a {
  position: relative;
  margin-right: 28px;
  padding: 6px 2px;
  font-size: 15px;
  color: var(--text-2);
  transition: color .2s var(--ease);
}
.main-nav a:hover, .main-nav a.is-active { color: var(--primary-strong); }
.main-nav a.is-active::after {
  content: "";
  position: absolute;
  left: 0; right: 0; bottom: -2px;         /* 不使用 inset 简写（87+） */
  height: 2px;
  border-radius: 2px;
  background: var(--primary);
}

/* ---------- Hero ---------- */
.hero { position: relative; overflow: hidden; padding: 88px 0 96px; }

.hero-bg { position: absolute; top: 0; left: 0; right: 0; bottom: 0; z-index: 0; } /* 不用 inset */
.blob { position: absolute; border-radius: 50%; filter: blur(70px); opacity: .55; }
.blob.b1 { width: 420px; height: 420px; left: -120px; top: -120px; background: #9fd6ff; animation: drift 14s ease-in-out infinite alternate; }
.blob.b2 { width: 360px; height: 360px; right: -80px; top: 30px; background: #c7b9ff; animation: drift 18s ease-in-out infinite alternate-reverse; }
.blob.b3 { width: 280px; height: 280px; left: 42%; bottom: 88px; background: #a8f0d8; opacity: .45; animation: drift 16s ease-in-out infinite alternate; }
@keyframes drift {
  from { transform: translate3d(0, 0, 0) scale(1); }
  to { transform: translate3d(40px, 26px, 0) scale(1.12); }
}

.hero-inner {
  position: relative;
  z-index: 1;
  display: -webkit-flex; display: flex;
  -webkit-align-items: center; align-items: center;
}
.hero-text { -webkit-flex: 1.15; flex: 1.15; padding-right: 48px; }
.hero-visual { -webkit-flex: .85; flex: .85; position: relative; }

.hero-eyebrow {
  display: inline-block;
  margin-bottom: 18px;
  padding: 5px 14px;
  font-size: 13px;
  font-weight: 600;
  color: var(--primary-strong);
  background: var(--primary-soft);
  border: 1px solid rgba(0, 103, 192, .22);
  border-radius: 999px;
}

.hero-title { font-size: 46px; line-height: 1.22; font-weight: 800; letter-spacing: -.01em; }
.grad-text {
  background: linear-gradient(92deg, #0067c0, #4cc2ff 60%, #37d0b6);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  color: var(--primary); /* 降级色 */
}
/* 服务保障标签组 + 正版声明警示 */
/* 固定两行、每行 4 个：4 列 grid（列宽取各列最宽标签） */
.hero-tags {
  display: grid;
  grid-template-columns: repeat(4, max-content);
  justify-content: start;
  gap: 10px 12px;                    /* grid gap：Chrome 66+ */
  list-style: none;
  padding: 0;
  margin: 22px 0 0;
}
.hero-tags li {
  display: -webkit-inline-flex; display: inline-flex;
  -webkit-align-items: center; align-items: center;
  padding: 7px 15px 7px 12px;
  background: rgba(255, 255, 255, .82);
  border: 1px solid var(--line);
  border-radius: 999px;
  font-size: 13px;
  font-weight: 600;
  color: var(--text);
  box-shadow: var(--shadow-1);
  backdrop-filter: blur(6px);
}
.hero-tags svg { width: 16px; height: 16px; margin-right: 7px; color: var(--primary); }

.hero-notice {
  display: -webkit-flex; display: flex;
  -webkit-align-items: flex-start; align-items: flex-start;
  max-width: 620px;
  margin: 12px 0 0;
  padding: 12px 16px;
  background: #fff6d9;
  border: 1px solid #f2d98a;
  border-radius: 12px;
  font-size: 13px;
  line-height: 1.7;
  color: #6f5310;
}
.hero-notice svg {
  width: 19px; height: 19px;
  margin-right: 10px;
  margin-top: 2px;
  -webkit-flex: none; flex: none;
  color: #c07a10;
}
.hero-notice b { font-weight: 700; color: #8a6714; }

.hero-cta { display: -webkit-flex; display: flex; margin-top: 32px; }
.hero-cta .btn { margin-right: 16px; }

.hero-stats {
  display: -webkit-flex; display: flex;
  list-style: none;
  padding: 0;
  margin-top: 48px;
  border-top: 1px solid var(--line);
  padding-top: 24px;
}
.hero-stats li { margin-right: 48px; }
.hero-stats li:last-child { margin-right: 0; }
.hero-stats strong { display: block; font-size: 24px; font-weight: 800; color: var(--primary-strong); }
.hero-stats span { font-size: 13px; color: var(--text-2); }

/* Hero 视觉区：大号 Win11 logo（直角四格，无透视） */
.logo-hero {
  width: 330px;
  height: 330px;
  margin: 0 auto;
  animation: floaty 7s ease-in-out infinite alternate;
  -webkit-filter: drop-shadow(0 26px 42px rgba(0, 103, 192, .38));
  filter: drop-shadow(0 26px 42px rgba(0, 103, 192, .38));
}
.logo-hero svg { width: 100%; height: 100%; display: block; }

@keyframes floaty {
  from { transform: translateY(0); }
  to { transform: translateY(-14px); }
}

.float-card {
  position: absolute;
  display: -webkit-flex; display: flex;
  -webkit-align-items: center; align-items: center;
  padding: 12px 18px 12px 14px;
  border-radius: var(--radius-l);
  background: var(--surface);
  box-shadow: var(--shadow-2);
  color: var(--primary-strong);
}
.float-card strong { display: block; font-size: 14px; color: var(--text); line-height: 1.3; }
.float-card span { font-size: 12px; color: var(--text-2); }
.float-card .icon { width: 26px; height: 26px; margin-right: 10px; }
.mini-float {
  position: absolute;
  display: block;
  -webkit-filter: drop-shadow(0 8px 16px rgba(0, 60, 120, .18));
  filter: drop-shadow(0 8px 16px rgba(0, 60, 120, .18));
}
.mini-float svg { width: 100%; height: 100%; display: block; }
/* 三个历史版本 logo 环绕大 logo 错落漂浮 */
.mf-win10 { width: 62px; height: 62px; right: -20px; top: -46px; animation: float-sm 6s .3s ease-in-out infinite alternate; }
.mf-win81 { width: 60px; height: 60px; left: -58px; top: 24px; animation: float-sm 7.5s .7s ease-in-out infinite alternate; }
.mf-win7 { width: 72px; height: 64px; left: -50px; bottom: -34px; animation: float-sm 6.8s 1s ease-in-out infinite alternate; }
@keyframes float-sm {
  from { transform: translateY(0); }
  to { transform: translateY(-10px); }
}

.float-card.fc1 { left: -2px; top: -86px; animation: floaty 6s .8s ease-in-out infinite alternate; }
.float-card.fc2 { right: -4px; bottom: -88px; animation: floaty 6s .3s ease-in-out infinite alternate-reverse; }

/* ---------- 区块通用 ---------- */
.section { padding: 84px 0; }
.section-alt { background: var(--bg-alt); transition: background-color .25s var(--ease); }

.section-head { text-align: center; margin-bottom: 44px; }
.section-eyebrow {
  font-size: 13px;
  font-weight: 700;
  letter-spacing: .18em;
  text-transform: uppercase;
  color: var(--primary);
  margin-bottom: 10px;
}
.section-title { font-size: 32px; font-weight: 800; letter-spacing: -.01em; }
.section-desc { margin-top: 12px; color: var(--text-2); font-size: 15px; }

/* ---------- 商品工具栏：分段控件（浅灰轨道 + 选中白色浮起） ---------- */
#products .section-head { margin-bottom: 18px; }   /* 收紧与上方描述的间距 */

.shop-toolbar {
  display: -webkit-flex; display: flex;
  -webkit-justify-content: center; justify-content: center;
  margin: 0 0 26px;
}

.filter-tabs {
  display: -webkit-inline-flex; display: inline-flex;
  padding: 3px;
  background: var(--surface-2);
  border: 1px solid var(--line);
  border-radius: 12px;
}
.filter-tab {
  display: -webkit-inline-flex; display: inline-flex;
  -webkit-align-items: center; align-items: center;
  margin-left: 2px;
  padding: 7px 18px;
  font-size: 13.5px;
  font-weight: 600;
  color: var(--text-2);
  border: none;
  border-radius: 9px;
  background: transparent;
  transition: color .18s var(--ease), background-color .18s var(--ease), box-shadow .18s var(--ease);
}

/* 迷你官方版本 logo（内联 SVG，形状/配色对照微软官方徽标） */
.mini-logo {
  width: 14px;
  height: 14px;
  margin-right: 7px;
  -webkit-flex: none; flex: none;
}

.filter-tab:first-child { margin-left: 0; }
.filter-tab:hover { color: var(--primary-strong); }
.filter-tab.is-active {
  color: var(--primary-strong);
  background: #fff;
  box-shadow: 0 1px 4px rgba(23, 32, 54, .14), 0 0 0 1px rgba(0, 103, 192, .2);
}

/* ---------- 商品卡片 ---------- */
/* ---------- 商品卡片 ---------- */
.product-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(268px, 1fr));
  gap: 24px; /* grid gap：Chrome 66+ 原生支持 */
}

.product-card {
  display: -webkit-flex; display: flex;
  -webkit-flex-direction: column; flex-direction: column;
  padding: 22px;
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: var(--radius-l);
  box-shadow: var(--shadow-1);
  transition: transform .22s var(--ease), box-shadow .22s var(--ease), border-color .22s var(--ease);
}
.product-card:hover {
  transform: translateY(-5px);
  box-shadow: var(--shadow-2);
  border-color: rgba(0, 103, 192, .4);
}

/* 封面"图片"块：蓝色底正方形。
   正方形比例用 padding-top hack 实现（aspect-ratio 需 Chrome 88，禁用）。 */
.pc-cover {
  position: relative;
  width: 100%;
  margin: 0 0 16px;
  padding-top: 100%; /* 高度 = 宽度 → 1:1 */
  -webkit-user-select: none;   /* 装饰性封面：禁止文字/图片被选中 */
  user-select: none;
  border-radius: var(--radius-l);
  overflow: hidden;
  background:
    radial-gradient(120% 90% at 85% 6%, rgba(255, 255, 255, .16) 0%, rgba(255, 255, 255, 0) 48%),
    linear-gradient(155deg, #0a3d7c 0%, #0f5cb8 46%, #1c7ed6 100%);
}

/* 版本笔记本展示图（透明素材），悬浮于底部信息块上方 */
.pc-cover-img {
  position: absolute;
  left: 50%;
  bottom: 31%;
  width: 80%;
  transform: translateX(-50%);
  transition: transform .3s var(--ease);
}
.product-card:hover .pc-cover-img { transform: translateX(-50%) scale(1.045); }

/* 封面左上角：微软官方 logo（白字标深底变体） */
.pc-ms {
  position: absolute;
  top: 12px;
  left: 12px;
  height: 21px;
}

/* 封面底部信息块：特性标签行 + 版名，整体渐变压暗 */
.pc-bottom {
  position: absolute;
  left: 0;
  right: 0;
  bottom: 0;
  padding: 30px 10px 14px;
  text-align: center;
  color: #fff;
  background: linear-gradient(180deg, rgba(5, 28, 62, 0) 0%, rgba(5, 28, 62, .66) 60%);
}

/* 特性标签行：4 等分 + 细分隔线 */
.pc-ftags {
  display: -webkit-flex; display: flex;
  list-style: none;
  padding: 0;
  margin: 0 0 9px;
}
.pc-ftags li {
  -webkit-flex: 1; flex: 1;
  font-size: 11px;
  font-weight: 500;
  letter-spacing: .02em;
  color: rgba(255, 255, 255, .96);
  white-space: nowrap;
}
.pc-ftags li + li { border-left: 1px solid rgba(255, 255, 255, .3); }

/* 版名两行：版本名（大）+ 规格（小） */
.pc-osname b { display: block; font-size: 23px; font-weight: 600; letter-spacing: .4px; line-height: 1.25; }
.pc-osname i { display: block; margin-top: 2px; font-style: normal; font-size: 14px; font-weight: 500; line-height: 1.3; color: rgba(255, 255, 255, .88); }

/* 热卖等角标：封面右上角，扁平纯色块（无渐变、无阴影） */
.pc-flag {
  position: absolute;
  top: 10px;
  right: 10px;
  padding: 3px 9px;
  font-size: 12px;
  font-weight: 600;
  color: #fff;
  background: #d9484b;
  border-radius: 6px;
}

.pc-foot {
  margin-top: auto;
  padding-top: 16px;
  border-top: 1px dashed var(--line);
  display: -webkit-flex; display: flex;
  -webkit-align-items: center; align-items: center;
  -webkit-justify-content: space-between; justify-content: space-between;
}

/* 限时特惠标签（左），价格靠右 */
.pc-promo {
  -webkit-flex: none; flex: none;
  padding: 2px 8px;
  font-size: 11.5px;
  font-weight: 700;
  color: #b45309;
  background: var(--warn-bg);
  border-radius: var(--radius-s);
}
.pc-price { display: -webkit-flex; display: flex; -webkit-align-items: baseline; align-items: baseline; }
.pc-price .cur { font-size: 15px; font-weight: 700; color: var(--danger); }
.pc-price .num { font-size: 28px; font-weight: 800; color: var(--danger); line-height: 1; margin-left: 2px; }
.pc-price .dec { font-size: 16px; font-weight: 800; color: var(--danger); }  /* 小数位缩小（基线对齐） */
.pc-origin { margin-right: 8px; font-size: 12px; color: var(--text-2); text-decoration: line-through; }

.pc-actions { display: -webkit-flex; display: flex; margin-top: 16px; }
.pc-actions .btn { -webkit-flex: 1; flex: 1; padding: 10px 12px; font-size: 14px; }

.empty-hint { padding: 48px 0; text-align: center; color: var(--text-2); }

/* 通用加载旋转环（API 等待态） */
.spinner {
  display: inline-block;
  width: 22px; height: 22px;
  border: 3px solid rgba(0, 103, 192, .18);
  border-top-color: var(--primary);
  border-radius: 50%;
  animation: spin .8s linear infinite;
}
@keyframes spin { to { transform: rotate(360deg); } }

/* 商品加载占位 / 加载失败（正式站：不回退演示数据） */
.load-hint {
  grid-column: 1 / -1;
  display: -webkit-flex; display: flex;
  -webkit-flex-direction: column; flex-direction: column;
  -webkit-align-items: center; align-items: center;
  padding: 64px 0 56px;
  text-align: center;
  color: var(--text-2);
  font-size: 14.5px;
}
.load-hint .spinner { margin-bottom: 16px; }
.load-hint .btn { margin-top: 18px; }

/* ---------- 步骤 ---------- */
.steps {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 24px; /* grid gap */
  list-style: none;
  counter-reset: none;
  padding: 0;
}
.step-card {
  position: relative;
  padding: 26px 22px;
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: var(--radius-l);
  box-shadow: var(--shadow-1);
}
.step-no {
  display: inline-block;
  font-size: 13px;
  font-weight: 800;
  color: var(--primary);
  letter-spacing: .08em;
  margin-bottom: 12px;
}
.step-card h3 { font-size: 17px; margin-bottom: 8px; }
.step-card p { font-size: 13.5px; color: var(--text-2); }

/* ---------- 保障 ---------- */
.guarantee-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 24px;
}
.g-card {
  padding: 26px 22px;
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: var(--radius-l);
  box-shadow: var(--shadow-1);
  transition: transform .2s var(--ease), box-shadow .2s var(--ease);
}
.g-card:hover { transform: translateY(-4px); box-shadow: var(--shadow-2); }
.g-icon {
  display: -webkit-inline-flex; display: inline-flex;
  -webkit-align-items: center; align-items: center;
  -webkit-justify-content: center; justify-content: center;
  width: 46px; height: 46px;
  border-radius: var(--radius-m);
  margin-bottom: 14px;
}
.g-icon .icon { width: 24px; height: 24px; }
.g-blue { background: #e3f0fc; color: #0067c0; }
.g-green { background: #dff7ea; color: #0f7b3f; }
.g-orange { background: #fdeede; color: #b45309; }
.g-purple { background: #efe7fb; color: #6b3fa0; }
.g-card h3 { font-size: 16px; margin-bottom: 6px; }
.g-card p { font-size: 13.5px; color: var(--text-2); }

/* ---------- FAQ（第一版：整体大卡 + 悬停行 + Q 序号徽章） ---------- */
.faq-list {
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: var(--radius-l);
  box-shadow: var(--shadow-1);
  padding: 10px;
  counter-reset: faqq;          /* 计数器自动生成 Q1、Q2… */
}
.faq-item {
  position: relative;
  counter-increment: faqq;
  border-radius: var(--radius-m);
  transition: background-color .2s var(--ease);
}
.faq-item + .faq-item { margin-top: 2px; }
.faq-item[open] { background: var(--surface-2); }
.faq-item summary {
  display: -webkit-flex; display: flex;
  -webkit-align-items: center; align-items: center;
  padding: 13px 14px;
  border-radius: var(--radius-m);
  cursor: pointer;
  list-style: none;
  /* Chrome 78 无 :focus-visible，鼠标点击后全局 :focus 的 outline
     会在展开内容上方残留一条蓝线；这里改为柔和的底色焦点反馈 */
  outline: none;
  transition: background-color .18s var(--ease);
}
.faq-item summary::-webkit-details-marker { display: none; } /* 隐藏原生三角 */
.faq-item summary:hover,
.faq-item summary:focus { background: var(--primary-soft); }
.faq-q {
  display: -webkit-inline-flex; display: inline-flex;
  -webkit-align-items: center; align-items: center;
  -webkit-justify-content: center; justify-content: center;
  width: 32px; height: 32px;
  margin-right: 14px;
  border-radius: 10px;
  font-size: 12.5px;
  line-height: 1;   /* 行高 1：避免继承 1.6 行高导致文字在徽章内视觉偏上 */
  font-weight: 800;
  letter-spacing: .02em;
  color: var(--primary-strong);
  background: var(--primary-soft);
  -webkit-flex: none; flex: none;
  transition: background-color .22s var(--ease), color .22s var(--ease);
}
/* 字形垂直补偿：Segoe UI 下 Q1 墨迹中心比徽章中心低 0.5px（实测 canvas TextMetrics），
   上移 0.5px 使字形视觉中心回到徽章中央 */
.faq-q::before {
  content: 'Q' counter(faqq);
  display: block;
  transform: translateY(-0.5px);
}
.faq-item[open] .faq-q { background: var(--primary); color: #fff; }

.faq-t {
  -webkit-flex: 1; flex: 1;
  font-size: 15px;
  font-weight: 600;
  padding-right: 12px;
  line-height: 1.45;
}
.faq-chevron {
  width: 9px; height: 9px;
  -webkit-flex: none; flex: none;
  margin-right: 6px;
  border-right: 2px solid var(--text-2);
  border-bottom: 2px solid var(--text-2);
  transform: rotate(45deg);
  transition: transform .22s var(--ease);
}
.faq-item[open] .faq-chevron { transform: rotate(225deg); border-color: var(--primary-strong); }
.faq-body {
  padding: 12px 16px 12px 60px;   /* 与标题文字左对齐：14 + 32 + 14；上下留白相等 */
  font-size: 14px;
  color: var(--text-2);
  line-height: 1.7;
}
.faq-body p + p { margin-top: 6px; }

/* Win 键提示组件：kbd 内嵌 Win11 风格纯色徽标 */
.kbd-win {
  display: -webkit-inline-flex; display: inline-flex;
  -webkit-align-items: center; align-items: center;
  vertical-align: middle;                 /* 与行内文字基线对齐 */
  white-space: nowrap;
}
.kw-logo {
  display: block;
  width: 12px; height: 12px;
  margin-right: 5px;
  -webkit-flex: none; flex: none;
  background: var(--primary);             /* Win11 纯色四格，深浅主题自适应 */
  border-radius: 2.5px;
  /* 四格镂空：用径向渐变打孔会引入前缀问题，这里改为实心圆角块 + 内部分割线 */
  background-image:
    linear-gradient(90deg, transparent 45%, rgba(255, 255, 255, .95) 45%, rgba(255, 255, 255, .95) 55%, transparent 55%),
    linear-gradient(0deg, transparent 45%, rgba(255, 255, 255, .95) 45%, rgba(255, 255, 255, .95) 55%, transparent 55%);
  background-size: 100% 100%;
  -webkit-background-clip: padding-box;
  background-clip: padding-box;
}

/* ---------- 页脚 ---------- */
.site-footer { background: var(--bg-alt); border-top: 1px solid var(--line); padding: 40px 0 28px; transition: background-color .25s var(--ease); }
.footer-inner {
  display: -webkit-flex; display: flex;
  -webkit-align-items: center; align-items: center;
  -webkit-justify-content: space-between; justify-content: space-between;
  padding-bottom: 22px;
  border-bottom: 1px solid var(--line);
}
.footer-brand { display: -webkit-flex; display: flex; -webkit-align-items: center; align-items: center; }
.footer-brand .brand-logo { margin-right: 12px; }
.footer-brand p { font-size: 14px; color: var(--text-2); }
.footer-links { display: -webkit-flex; display: flex; }
.footer-links a { margin-left: 26px; font-size: 14px; color: var(--text-2); transition: color .2s var(--ease); }
.footer-links a:hover { color: var(--primary-strong); }
.footer-bottom {
  display: -webkit-flex; display: flex;
  -webkit-justify-content: center; justify-content: center;
  -webkit-flex-wrap: wrap; flex-wrap: wrap;
  padding-top: 18px;
  text-align: center;
}
.footer-bottom p { font-size: 12.5px; color: var(--text-2); margin: 4px 12px 0 0; }

/* ---------- 滚动显现（JS 存在时才启用初始隐藏） ---------- */
.js .reveal { opacity: 0; transform: translateY(18px); }
.reveal.is-in { opacity: 1; transform: none; transition: opacity .6s var(--ease), transform .6s var(--ease); }
.reveal.is-in:nth-child(2) { transition-delay: .08s; }
.reveal.is-in:nth-child(3) { transition-delay: .16s; }
.reveal.is-in:nth-child(4) { transition-delay: .24s; }

@media (prefers-reduced-motion: reduce) { /* Chrome 74+ */
  html { scroll-behavior: auto; }
  *, *::before, *::after { animation-duration: .01s !important; transition-duration: .01s !important; }
  .js .reveal { opacity: 1; transform: none; }
}

/* 打印时隐藏交互组件 */
@media print {
  .promo-bar, .site-header, .hero-visual, .shop-toolbar, .toast-wrap,
  .social-proof, .modal-mask { display: none; }
}

/* Header activation entry: original fixed header, aligned to its right edge. */
.header-activate { margin-left: auto; }

/* Simple brand strip copied from site2; the original Logo pixels are unchanged. */
.site-brand-strip { height: 36px; padding: 0 10px; display: flex; align-items: center; background: #f5f5f5; }
.site-logo-link { display: inline-block; vertical-align: middle; }
.site-logo { position: relative; display: block; width: 36px; height: 30.317356px; overflow: hidden; }
.site-logo .site-logo-image { position: absolute; width: 87.857851px; height: auto; left: -24.307438px; top: -14.638016px; }

/* Clearer hero copy, keeping the original fixed desktop composition. */
.hero { padding: 76px 0 84px; }
.hero-description { margin-top: 24px; color: var(--text-2); font-size: 17px; line-height: 1.8; }

/* Unified site brand and product header. Original Logo pixels are unchanged. */
.site-header { background: #fff; }
.header-inner { height: 72px; }
.site-logo { width: 47.497547px; height: 40px; }
.site-logo .site-logo-image { width: 115.917566px; left: -32.070658px; top: -19.313052px; }
.header-separator { display: block; flex: none; width: 1px; height: 28px; margin: 0 20px; background: var(--line); }

/* Flat activation buttons: solid Microsoft blue, small corners, no elevation. */
.btn, .btn-lg { border-radius: 2px; box-shadow: none; transition: background-color .15s var(--ease), color .15s var(--ease), border-color .15s var(--ease); }
.btn:active { transform: none; }
.btn-primary { background: var(--primary); border-color: var(--primary); box-shadow: none; }
.btn-primary:hover, .btn-primary:focus { background: var(--primary-strong); border-color: var(--primary-strong); box-shadow: none; }
.btn-primary:active { background: #004578; border-color: #004578; }
.btn-ghost { color: var(--primary); background: #fff; border-color: var(--primary); box-shadow: none; }
.btn-ghost:hover, .btn-ghost:focus { color: var(--primary-strong); background: var(--primary-soft); border-color: var(--primary-strong); box-shadow: none; }
/* Feature rows now contain three equally sized labels. Existing flex sizing is retained. */

/* Card surfaces use the activation button's solid blue and small corners. */
.product-card, .pc-cover { border-radius: 2px; }
.pc-cover { background: var(--primary); }
.pc-bottom { background: transparent; }

/* Version filters share the activation button's small corners and solid blue. */
.filter-tabs, .filter-tab { border-radius: 2px; }
.filter-tab.is-active { color: #fff; background: var(--primary); box-shadow: none; }
.filter-tab.is-active:hover { background: var(--primary-strong); }
.filter-tab.is-active .mini-logo { filter: brightness(0) invert(1); }

/* A clearer hero hierarchy: product label, compact headline and version details. */
.hero-product-name { margin-bottom: 12px; color: var(--primary); font-size: 15px; font-weight: 600; letter-spacing: .04em; }
.hero-title { font-size: 40px; font-weight: 700; line-height: 1.25; letter-spacing: 0; }
.hero-title-accent { color: var(--primary); }
.hero-description { margin-top: 20px; font-size: 16px; line-height: 1.85; }
.hero-cta { margin-top: 28px; }
.hero-cta .btn-lg { min-width: 156px; padding: 12px 24px; }

/* Lower the hero composition and give the product label a subtle identity. */
.hero { padding: 116px 0 104px; }
.hero-product-name { display: -webkit-inline-flex; display: inline-flex; -webkit-align-items: center; align-items: center; margin-bottom: 18px; padding: 6px 12px; border: 1px solid rgba(0, 103, 192, .18); border-radius: 2px; background: rgba(255, 255, 255, .78); }
.hero-product-name::before { content: ""; display: block; flex: none; width: 3px; height: 14px; margin-right: 8px; background: var(--primary); }
.hero-title { font-size: 48px; line-height: 1.2; }

/* Emphasize the primary headline while keeping a smaller blue second line. */
.hero-title-main { display: block; font-size: 80px; line-height: 1.12; letter-spacing: -.02em; white-space: nowrap; }
.hero-title-accent { display: block; margin-top: 8px; font-size: 48px; line-height: 1.2; }

/* Match both headline lines at80px. */
.hero-title-accent { font-size: 80px; }

/* Separate the message from system compatibility details. */
.hero-title { font-weight: 600; }
.hero-title-main, .hero-title-accent { line-height: 1.08; letter-spacing: -.025em; }
.hero-title-accent { margin-top: 4px; }
.hero-compatibility { width: 100%; max-width: 520px; margin-top: 26px; padding: 14px 18px; border: 1px solid rgba(0, 103, 192, .14); border-left: 3px solid var(--primary); border-radius: 2px; background: rgba(255, 255, 255, .68); }
.hero-support-label { color: var(--primary); font-size: 15px; font-weight: 600; line-height: 1.4; }
.hero-systems { display: -webkit-flex; display: flex; list-style: none; margin: 10px 0 0; padding: 0; }
.hero-systems li { color: var(--text); font-size: 15px; font-weight: 600; line-height: 1.5; white-space: nowrap; }
.hero-systems li + li { margin-left: 18px; }
.hero-compatibility .hero-description { margin-top: 10px; color: var(--text-2); font-size: 14px; line-height: 1.7; }
.hero-cta { margin-top: 24px; }

/* Give the headline lines more space and identify each supported OS visually. */
.hero-title-accent { margin-top: 16px; }
.hero-compatibility { max-width: 560px; }
.hero-systems li { display: -webkit-inline-flex; display: inline-flex; -webkit-align-items: center; align-items: center; }
.hero-systems li + li { margin-left: 16px; }
.hero-system-icon { width: 22px; height: 22px; margin-right: 8px; -webkit-flex: none; flex: none; }

/* Download feedback shares the site's Microsoft blue, typography and flat controls. */
.download-feedback { position: fixed; z-index: 1000; top: 0; right: 0; bottom: 0; left: 0; display: flex; align-items: center; justify-content: center; padding: 24px; background: rgba(15, 23, 42, .42); }
.download-feedback-panel { position: relative; width: 620px; max-width: 100%; max-height: 100%; overflow-y: auto; padding: 32px; border: 1px solid var(--line); border-top: 3px solid var(--primary); border-radius: 2px; background: #fff; box-shadow: 0 12px 40px rgba(15, 23, 42, .16); text-align: left; }
.download-feedback-close { position: absolute; top: 10px; right: 10px; width: 28px; height: 28px; padding: 0; border: 0; border-radius: 2px; background: transparent; color: var(--text-2); cursor: pointer; }
.download-feedback-close::before, .download-feedback-close::after { position: absolute; top: 13px; left: 6px; width: 16px; height: 2px; background: currentColor; content: ""; }
.download-feedback-close::before { transform: rotate(45deg); }
.download-feedback-close::after { transform: rotate(-45deg); }
.download-feedback-close:hover { color: var(--text); background: var(--primary-soft); }
.download-feedback-heading { display: flex; align-items: center; padding-right: 12px; }
.download-feedback-icon { width: 44px; height: 44px; margin-right: 16px; flex: none; }
.download-feedback-title { margin: 0; color: var(--text); font-size: 24px; font-weight: 600; line-height: 1.4; }
.download-feedback-description { margin: 24px 0 0; color: var(--text-2); font-size: 16px; line-height: 1.75; }
.download-feedback-file { display: flex; align-items: center; margin-top: 18px; padding: 14px 16px; border: 1px solid var(--line); border-radius: 2px; background: var(--primary-soft); font-size: 14px; line-height: 1.6; }
.download-feedback-file span { margin-right: 20px; color: var(--text-2); }
.download-feedback-file strong { color: var(--text); font-size: 15px; font-weight: 600; }
.download-feedback-help { margin: 20px 0 0; color: var(--text-2); font-size: 14px; line-height: 1.8; }
.download-feedback-help kbd { padding: 2px 6px; border: 1px solid var(--line); border-radius: 2px; background: #fff; box-shadow: none; color: var(--text); font-family: inherit; font-size: 13px; }
.download-feedback-actions { display: flex; justify-content: flex-end; margin-top: 24px; padding-top: 20px; border-top: 1px solid var(--line); }
.download-feedback-confirm { min-width: 112px; padding: 10px 24px; border: 1px solid var(--primary); border-radius: 2px; color: #fff; background: var(--primary); box-shadow: none; font: inherit; font-size: 16px; font-weight: 600; line-height: 1.5; cursor: pointer; }
.download-feedback-confirm:hover { border-color: var(--primary-strong); background: var(--primary-strong); }
.download-feedback-close:focus, .download-feedback-confirm:focus { outline: 2px solid #005a9e; outline-offset: 3px; }
@media print { .download-feedback { display: none; } }