/* =====================================================================
   x360ce · Xbox 360 Controller Emulator 官方网站
   配色取自 Logo：银灰金属机身 + 蓝色按键 + 深色轮廓
   纯静态 HTML5 + CSS，扁平现代专业风格
   ===================================================================== */

/* ---------- 设计令牌 ---------- */
:root {
  /* 品牌蓝（Logo 按键） */
  --blue-700: #14579c;
  --blue-600: #1d6cc2;
  --blue-500: #2f80d8;
  --blue-400: #5fa3e6;
  --blue-300: #93c2ee;
  --blue-100: #e1eefb;
  --blue-50:  #f1f7fd;

  /* 深石板色（机身暗部 / 轮廓） */
  --ink-900: #162431;
  --ink-800: #1f2f3e;
  --ink-700: #2d4051;
  --ink-600: #47586a;
  --ink-500: #637486;
  --ink-400: #8898a8;

  /* 银灰中性色 */
  --silver-300: #ccd7e1;
  --silver-200: #dde5ed;
  --silver-100: #edf2f7;
  --silver-50:  #f6f9fc;
  --white: #ffffff;

  /* 状态色 */
  --green-700: #157a52;
  --green-600: #1c9362;
  --green-100: #dcf1e7;
  --green-50:  #edf8f2;
  --amber-700: #9c6112;
  --amber-600: #c07d17;
  --amber-100: #f8ead0;
  --amber-50:  #fcf5e7;
  --red-700: #a82e2e;
  --red-600: #cf3b3b;
  --red-100: #f8dede;
  --red-50:  #fceeee;

  /* 字体 */
  --font-sans: "IBM Plex Sans", "Noto Sans SC", -apple-system, BlinkMacSystemFont,
    "Segoe UI", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
  --font-mono: "IBM Plex Mono", "Noto Sans SC", "SFMono-Regular", Consolas,
    "Courier New", monospace;

  /* 形状与阴影 */
  --radius-sm: 8px;
  --radius: 12px;
  --radius-lg: 18px;
  --shadow-sm: 0 1px 2px rgba(22, 36, 49, .06);
  --shadow: 0 8px 28px rgba(22, 36, 49, .09);
  --shadow-lg: 0 24px 60px rgba(22, 36, 49, .16);
  --maxw: 1180px;
  --header-h: 68px;
}

/* ---------- 基础重置 ---------- */
*, *::before, *::after { box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; scroll-behavior: smooth; scroll-padding-top: calc(var(--header-h) + 16px); }
body {
  margin: 0;
  font-family: var(--font-sans);
  font-size: 16px;
  line-height: 1.7;
  color: var(--ink-800);
  background: var(--white);
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}
img, svg { display: block; max-width: 100%; }
a { color: var(--blue-600); text-decoration: none; }
a:hover { color: var(--blue-700); }
button { font-family: inherit; cursor: pointer; }
h1, h2, h3, h4 { color: var(--ink-900); line-height: 1.28; font-weight: 700; margin: 0 0 .5em; }
p { margin: 0 0 1em; }
ul, ol { margin: 0 0 1em; padding-left: 1.3em; }
li { margin-bottom: .35em; }
code { font-family: var(--font-mono); font-size: .9em; background: var(--silver-100); padding: .15em .4em; border-radius: 5px; color: var(--blue-700); }
small { font-size: .85em; }

/* ---------- 布局容器 ---------- */
.container { width: 100%; max-width: var(--maxw); margin: 0 auto; padding: 0 24px; }
.section { padding: 78px 0; }
.section.tight { padding: 56px 0; }
.section.alt { background: var(--silver-50); }
.section.blue { background: linear-gradient(160deg, var(--blue-50), #fff 70%); }
.section-head { max-width: 720px; margin: 0 auto 52px; text-align: center; }
.section-head.left { margin-left: 0; text-align: left; }
.section-title { font-size: clamp(26px, 3.2vw, 36px); letter-spacing: -.01em; }
.section-desc { color: var(--ink-600); font-size: 17px; margin-bottom: 0; }
.eyebrow {
  display: inline-flex; align-items: center; gap: 8px;
  font-size: 13px; font-weight: 600; letter-spacing: .04em;
  color: var(--blue-700); background: var(--blue-100);
  padding: 5px 13px; border-radius: 100px; margin-bottom: 20px;
}
.eyebrow::before { content: ""; width: 7px; height: 7px; border-radius: 50%; background: var(--blue-500); }

/* ---------- 按钮 ---------- */
.btn {
  display: inline-flex; align-items: center; justify-content: center; gap: 9px;
  font-size: 15px; font-weight: 600; line-height: 1;
  padding: 14px 26px; border-radius: 10px; border: 1px solid transparent;
  transition: transform .12s ease, background .18s ease, box-shadow .18s ease, color .18s ease;
  white-space: nowrap;
}
.btn svg { width: 18px; height: 18px; }
.btn-primary { background: var(--blue-600); color: #fff; box-shadow: 0 8px 20px rgba(29, 108, 194, .28); }
.btn-primary:hover { background: var(--blue-700); color: #fff; transform: translateY(-1px); }
.btn-secondary { background: #fff; color: var(--ink-800); border-color: var(--silver-300); }
.btn-secondary:hover { border-color: var(--blue-400); color: var(--blue-700); background: var(--blue-50); }
.btn-ghost { background: transparent; color: var(--blue-700); padding-left: 8px; padding-right: 8px; }
.btn-ghost:hover { background: var(--blue-100); }
.btn-lg { padding: 16px 32px; font-size: 16px; }
.btn-block { width: 100%; }
.btn .caret { font-size: 12px; }

/* ---------- 顶部导航 ---------- */
.site-header {
  position: sticky; top: 0; z-index: 100;
  background: rgba(255, 255, 255, .92); backdrop-filter: saturate(160%) blur(10px);
  border-bottom: 1px solid var(--silver-200);
  transition: box-shadow .2s ease;
}
.site-header.scrolled { box-shadow: var(--shadow-sm); }
.header-inner { display: flex; align-items: center; gap: 24px; height: var(--header-h); }
.brand { display: flex; align-items: center; gap: 12px; flex-shrink: 0; }
.brand-logo { width: 40px; height: 40px; object-fit: contain; }
.brand-name { font-weight: 700; font-size: 19px; color: var(--ink-900); letter-spacing: -.01em; line-height: 1.1; }
.brand-sub { font-size: 11px; color: var(--ink-500); line-height: 1.1; letter-spacing: .02em; }
.nav { display: flex; align-items: center; gap: 4px; margin-left: auto; }
.nav-link {
  padding: 9px 14px; border-radius: 8px; font-size: 15px; font-weight: 500;
  color: var(--ink-700); transition: background .15s, color .15s;
}
.nav-link:hover { color: var(--blue-700); background: var(--blue-50); }
.nav-link.active { color: var(--blue-700); background: var(--blue-100); font-weight: 600; }
.header-cta { margin-left: 14px; flex-shrink: 0; }
.header-cta .btn { padding: 11px 20px; }
.nav-toggle {
  display: none; margin-left: auto; width: 44px; height: 44px;
  background: none; border: 0; padding: 10px; border-radius: 8px;
}
.nav-toggle span { display: block; height: 2px; background: var(--ink-800); margin: 5px 0; border-radius: 2px; transition: transform .2s, opacity .2s; }
.nav-toggle.open span:nth-child(1) { transform: translateY(7px) rotate(45deg); }
.nav-toggle.open span:nth-child(2) { opacity: 0; }
.nav-toggle.open span:nth-child(3) { transform: translateY(-7px) rotate(-45deg); }

/* ---------- Hero ---------- */
.hero { position: relative; padding: 72px 0 64px; overflow: hidden; background: linear-gradient(170deg, var(--silver-50) 0%, #fff 58%); }
.hero::after {
  content: ""; position: absolute; right: -160px; top: -160px; width: 480px; height: 480px;
  background: radial-gradient(circle, var(--blue-100), transparent 68%); opacity: .7; pointer-events: none;
}
.hero-grid { display: grid; grid-template-columns: 1.05fr .95fr; gap: 56px; align-items: center; position: relative; z-index: 1; }
.hero-title { font-size: clamp(32px, 4.6vw, 52px); font-weight: 700; letter-spacing: -.02em; margin-bottom: 20px; }
.hero-title .accent { color: var(--blue-600); white-space: nowrap; }
.hero-desc { font-size: 18px; color: var(--ink-600); max-width: 540px; margin-bottom: 32px; }
.hero-actions { display: flex; flex-wrap: wrap; gap: 14px; margin-bottom: 36px; }
.hero-trust { display: flex; align-items: center; gap: 9px; font-size: 13.5px; color: var(--ink-500); }
.hero-trust svg { width: 17px; height: 17px; color: var(--green-600); flex-shrink: 0; }
.hero-stats { display: grid; grid-template-columns: repeat(4, auto); gap: 34px; margin-top: 42px; padding-top: 30px; border-top: 1px solid var(--silver-200); }
.stat-num { font-size: 27px; font-weight: 700; color: var(--ink-900); line-height: 1.1; font-family: var(--font-mono); letter-spacing: -.02em; }
.stat-num .u { color: var(--blue-600); }
.stat-label { font-size: 13px; color: var(--ink-500); margin-top: 3px; }

/* 软件窗口框 */
.app-frame {
  background: #fff; border-radius: var(--radius-lg); box-shadow: var(--shadow-lg);
  border: 1px solid var(--silver-200); overflow: hidden; transform: rotate(.6deg);
}
.app-frame.flat { transform: none; }
.app-titlebar { display: flex; align-items: center; gap: 7px; padding: 11px 15px; background: var(--silver-100); border-bottom: 1px solid var(--silver-200); }
.app-dot { width: 11px; height: 11px; border-radius: 50%; }
.app-dot.r { background: #ff5f57; } .app-dot.y { background: #febc2e; } .app-dot.g { background: #28c840; }
.app-title { margin-left: 10px; font-size: 12.5px; color: var(--ink-500); font-family: var(--font-mono); }
.app-frame img { width: 100%; height: auto; }
.hero-badge-row { display: flex; gap: 10px; margin-top: 18px; flex-wrap: wrap; justify-content: center; }
.host-badge { font-size: 12.5px; color: var(--ink-600); background: #fff; border: 1px solid var(--silver-300); padding: 6px 13px; border-radius: 100px; }

/* ---------- 通用网格卡片 ---------- */
.grid-3 { display: grid; grid-template-columns: repeat(3, 1fr); gap: 24px; }
.grid-2 { display: grid; grid-template-columns: repeat(2, 1fr); gap: 28px; }
.grid-4 { display: grid; grid-template-columns: repeat(4, 1fr); gap: 20px; }

.card {
  background: #fff; border: 1px solid var(--silver-200); border-radius: var(--radius);
  padding: 28px; transition: transform .18s ease, box-shadow .18s ease, border-color .18s ease;
}
.card:hover { transform: translateY(-3px); box-shadow: var(--shadow); border-color: var(--blue-300); }
.card-icon {
  width: 48px; height: 48px; border-radius: 11px; display: flex; align-items: center; justify-content: center;
  background: var(--blue-50); color: var(--blue-600); margin-bottom: 18px;
}
.card-icon svg { width: 24px; height: 24px; }
.card-title { font-size: 18px; margin-bottom: 8px; }
.card-desc { color: var(--ink-600); font-size: 14.5px; margin-bottom: 0; }

/* 使用场景卡片（含实物图） */
.usecase-card { padding: 0; overflow: hidden; display: flex; flex-direction: column; }
.usecase-thumb { aspect-ratio: 16 / 10; background: var(--silver-100); overflow: hidden; position: relative; }
.usecase-thumb img { width: 100%; height: 100%; object-fit: cover; transition: transform .3s ease; }
.usecase-card:hover .usecase-thumb img { transform: scale(1.05); }
.usecase-body { padding: 22px 24px 26px; }
.usecase-tag { font-size: 12px; font-weight: 600; color: var(--blue-700); letter-spacing: .03em; margin-bottom: 8px; }
.usecase-title { font-size: 17.5px; margin-bottom: 8px; }
.usecase-desc { font-size: 14px; color: var(--ink-600); margin-bottom: 0; }

/* ---------- 工作原理 ---------- */
.flow {
  display: flex; align-items: stretch; justify-content: center; gap: 0; flex-wrap: wrap;
  margin: 8px 0 44px;
}
.flow-node {
  background: #fff; border: 1px solid var(--silver-300); border-radius: var(--radius);
  padding: 18px 22px; text-align: center; min-width: 138px; box-shadow: var(--shadow-sm);
}
.flow-node .ico { display: flex; justify-content: center; margin-bottom: 9px; color: var(--blue-600); }
.flow-node .ico svg { width: 28px; height: 28px; }
.flow-node strong { display: block; font-size: 15px; color: var(--ink-900); }
.flow-node span { font-size: 12.5px; color: var(--ink-500); }
.flow-arrow { display: flex; align-items: center; padding: 0 12px; color: var(--blue-400); }
.flow-arrow svg { width: 26px; height: 26px; }
.arch-cols { display: grid; grid-template-columns: 1fr 1fr; gap: 26px; }
.arch-card { background: #fff; border: 1px solid var(--silver-200); border-radius: var(--radius-lg); overflow: hidden; }
.arch-head { padding: 22px 28px; border-bottom: 1px solid var(--silver-200); display: flex; align-items: center; gap: 14px; }
.arch-head .ver { font-family: var(--font-mono); font-weight: 600; font-size: 15px; }
.arch-pill { font-size: 12px; font-weight: 600; padding: 4px 12px; border-radius: 100px; margin-left: auto; }
.arch-pill.rec { background: var(--green-100); color: var(--green-700); }
.arch-pill.leg { background: var(--silver-200); color: var(--ink-600); }
.arch-body { padding: 24px 28px 28px; }
.arch-body ul { margin-bottom: 0; }
.arch-body li { font-size: 14.5px; color: var(--ink-700); }

/* ---------- 版本卡片 ---------- */
.version-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 26px; align-items: start; }
.version-card { background: #fff; border: 1px solid var(--silver-200); border-radius: var(--radius-lg); overflow: hidden; box-shadow: var(--shadow-sm); }
.version-card.featured { border-color: var(--blue-400); box-shadow: var(--shadow); }
.version-ribbon { background: var(--blue-600); color: #fff; font-size: 12.5px; font-weight: 600; text-align: center; padding: 7px; }
.version-inner { padding: 30px; }
.version-name { font-size: 21px; margin-bottom: 4px; }
.version-id { font-family: var(--font-mono); color: var(--blue-700); font-size: 15px; font-weight: 600; }
.version-meta { list-style: none; padding: 0; margin: 20px 0 24px; }
.version-meta li { display: flex; gap: 10px; font-size: 14px; color: var(--ink-700); padding: 7px 0; border-bottom: 1px dashed var(--silver-200); }
.version-meta li:last-child { border-bottom: 0; }
.version-meta .k { color: var(--ink-500); min-width: 76px; flex-shrink: 0; }
.version-meta .v { font-weight: 500; }

/* ---------- 步骤 ---------- */
.steps { list-style: none; padding: 0; margin: 0; counter-reset: step; display: grid; gap: 18px; }
.steps.cols-2 { grid-template-columns: 1fr 1fr; }
.step { display: flex; gap: 18px; background: #fff; border: 1px solid var(--silver-200); border-radius: var(--radius); padding: 22px 24px; }
.step-num {
  counter-increment: step; flex-shrink: 0; width: 38px; height: 38px; border-radius: 10px;
  background: var(--blue-600); color: #fff; font-weight: 700; font-family: var(--font-mono);
  display: flex; align-items: center; justify-content: center; font-size: 16px;
}
.step-num::before { content: counter(step); }
.step-title { font-size: 16px; margin-bottom: 4px; }
.step-desc { font-size: 14px; color: var(--ink-600); margin-bottom: 0; }

/* ---------- 表格 ---------- */
.table-wrap { border: 1px solid var(--silver-200); border-radius: var(--radius); overflow: hidden; box-shadow: var(--shadow-sm); background: #fff; }
.spec-table { width: 100%; border-collapse: collapse; table-layout: fixed; font-size: 14.5px; }
.spec-table th, .spec-table td { text-align: left; padding: 14px 20px; border-bottom: 1px solid var(--silver-200); vertical-align: top; }
.spec-table tr:last-child td { border-bottom: 0; }
.spec-table thead th { background: var(--silver-100); color: var(--ink-900); font-weight: 600; font-size: 13.5px; }
.spec-table .req { width: 26%; font-weight: 600; color: var(--ink-900); }
.spec-table code { white-space: nowrap; }

/* ---------- 提示框 ---------- */
.callout { display: flex; gap: 14px; padding: 18px 22px; border-radius: var(--radius); font-size: 14.5px; margin: 22px 0; }
.callout svg { width: 22px; height: 22px; flex-shrink: 0; margin-top: 2px; }
.callout p:last-child { margin-bottom: 0; }
.callout.info { background: var(--blue-50); border: 1px solid var(--blue-100); color: var(--blue-700); }
.callout.success { background: var(--green-50); border: 1px solid var(--green-100); color: var(--green-700); }
.callout.warning { background: var(--amber-50); border: 1px solid var(--amber-100); color: var(--amber-700); }
.callout.danger { background: var(--red-50); border: 1px solid var(--red-100); color: var(--red-700); }
.callout a { font-weight: 600; text-decoration: underline; }

/* ---------- FAQ 折叠 ---------- */
.faq { display: grid; gap: 12px; max-width: 860px; margin: 0 auto; }
.faq-item { background: #fff; border: 1px solid var(--silver-200); border-radius: var(--radius); overflow: hidden; }
.faq-q {
  width: 100%; display: flex; align-items: center; gap: 14px; text-align: left;
  background: none; border: 0; padding: 19px 22px; font-size: 16px; font-weight: 600; color: var(--ink-900);
}
.faq-q .qmark { font-family: var(--font-mono); color: var(--blue-600); font-size: 14px; flex-shrink: 0; }
.faq-q .chev { margin-left: auto; flex-shrink: 0; transition: transform .22s ease; color: var(--ink-500); }
.faq-q .chev svg { width: 19px; height: 19px; }
.faq-item.open .faq-q .chev { transform: rotate(180deg); color: var(--blue-600); }
.faq-a { max-height: 0; overflow: hidden; transition: max-height .28s ease; }
.faq-a-inner { padding: 0 22px 20px 52px; font-size: 14.5px; color: var(--ink-700); }
.faq-a-inner p:last-child { margin-bottom: 0; }

/* ---------- 时间轴（三列网格，点轴像素对齐） ---------- */
.timeline { max-width: 920px; margin: 0 auto; }
.tl-row { display: grid; grid-template-columns: 180px 40px 1fr; }
.tl-time { text-align: right; padding: 0 22px 42px 0; }
.tl-time .y { font-family: var(--font-mono); font-weight: 600; color: var(--blue-700); font-size: 15.5px; }
.tl-time .d { font-size: 12.5px; color: var(--ink-500); }
.tl-axis { position: relative; display: flex; justify-content: center; }
.tl-axis::before { content: ""; position: absolute; top: 4px; bottom: -10px; width: 2px; background: var(--silver-300); }
.tl-dot {
  position: relative; z-index: 1; width: 15px; height: 15px; border-radius: 50%;
  background: #fff; border: 3px solid var(--blue-500); margin-top: 4px; justify-self: center;
}
.tl-dot.solid { background: var(--blue-600); border-color: var(--blue-600); }
.tl-content { padding: 0 0 42px 26px; }
.tl-content h4 { font-size: 16.5px; margin-bottom: 5px; }
.tl-content p { font-size: 14px; color: var(--ink-600); margin-bottom: 0; }
.tl-row:last-child .tl-time, .tl-row:last-child .tl-content { padding-bottom: 0; }
.tl-row:last-child .tl-axis::before { bottom: calc(100% - 12px); }

/* ---------- 图文交错特性行 ---------- */
.feature-row { display: grid; grid-template-columns: 1fr 1fr; gap: 56px; align-items: center; margin-bottom: 84px; }
.feature-row:last-child { margin-bottom: 0; }
.feature-row.reverse .feature-media { order: 2; }
.feature-media .app-frame { box-shadow: var(--shadow); }
.feature-kicker { font-size: 13px; font-weight: 600; color: var(--blue-700); letter-spacing: .04em; margin-bottom: 12px; }
.feature-h { font-size: 27px; margin-bottom: 14px; }
.feature-text { color: var(--ink-600); font-size: 15.5px; }
.feature-list { list-style: none; padding: 0; margin: 18px 0 0; }
.feature-list li { display: flex; gap: 11px; font-size: 14.5px; color: var(--ink-700); margin-bottom: 11px; }
.feature-list svg { width: 19px; height: 19px; color: var(--green-600); flex-shrink: 0; margin-top: 3px; }

/* 代码块 */
.code-block { background: var(--ink-900); color: #d7e4f2; border-radius: var(--radius); padding: 20px 22px; font-family: var(--font-mono); font-size: 13.5px; line-height: 1.8; overflow-x: auto; margin: 18px 0 0; }
.code-block .cm { color: #7f97ad; }
.code-block .fm { color: var(--blue-300); }
.chart-box { width: 100%; height: 340px; }

/* ---------- 面包屑 ---------- */
.breadcrumb { font-size: 13.5px; color: var(--ink-500); display: flex; gap: 8px; align-items: center; flex-wrap: wrap; padding: 20px 0 0; }
.breadcrumb a { color: var(--ink-500); }
.breadcrumb a:hover { color: var(--blue-700); }
.breadcrumb .sep { color: var(--silver-300); }
.breadcrumb .cur { color: var(--ink-800); font-weight: 500; }

/* 页面头（内页） */
.page-hero { background: linear-gradient(165deg, var(--silver-50), #fff 64%); padding: 8px 0 54px; border-bottom: 1px solid var(--silver-200); }
.page-title { font-size: clamp(28px, 4vw, 42px); letter-spacing: -.02em; margin: 18px 0 14px; }
.page-desc { font-size: 17px; color: var(--ink-600); max-width: 680px; margin-bottom: 0; }

/* ---------- CTA 横幅 ---------- */
.cta-band { background: linear-gradient(140deg, var(--blue-700), var(--blue-600) 60%, var(--blue-500)); border-radius: var(--radius-lg); padding: 54px 48px; display: flex; align-items: center; justify-content: space-between; gap: 32px; color: #fff; box-shadow: var(--shadow-lg); }
.cta-band h2 { color: #fff; font-size: clamp(23px, 3vw, 31px); margin-bottom: 8px; }
.cta-band p { color: rgba(255,255,255,.85); margin-bottom: 0; font-size: 15.5px; }
.cta-band .btn-primary { background: #fff; color: var(--blue-700); box-shadow: 0 10px 24px rgba(0,0,0,.18); }
.cta-band .btn-primary:hover { background: var(--silver-100); color: var(--blue-700); }

/* ---------- 下载弹窗 ---------- */
.modal-backdrop {
  position: fixed; inset: 0; z-index: 200; background: rgba(18, 30, 42, .55);
  display: flex; align-items: center; justify-content: center; padding: 20px;
  opacity: 0; visibility: hidden; transition: opacity .22s ease, visibility .22s;
}
.modal-backdrop.open { opacity: 1; visibility: visible;  left: 0;
  right: 0;
  top: 0;
  bottom: 0;}
  button { outline: none } 
.modal {
  background: #fff; border-radius: var(--radius-lg); width: 100%; max-width: 620px;
  max-height: 92vh; overflow-y: auto; box-shadow: var(--shadow-lg);
  transform: translateY(16px) scale(.98); transition: transform .24s ease;
}
.modal-backdrop.open .modal { transform: translateY(0) scale(1); }
.modal-head { display: flex; align-items: flex-start; justify-content: space-between; gap: 16px; padding: 28px 30px 0; }
.modal-title { font-size: 21px; margin-bottom: 5px; }
.modal-sub { font-size: 13.5px; color: var(--ink-500); margin-bottom: 0; }
.modal-close { background: var(--silver-100); border: 0; width: 36px; height: 36px; border-radius: 9px; display: flex; align-items: center; justify-content: center; color: var(--ink-600); flex-shrink: 0; }
.modal-close:hover { background: var(--silver-200); color: var(--ink-900); }
.modal-close svg { width: 18px; height: 18px; }
.modal-body { padding: 24px 30px 30px; }
.qr-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 18px; }
.qr-card { border: 1px solid var(--silver-200); border-radius: var(--radius); padding: 28px; text-align: center; background: var(--silver-50); }
.qr-box {
  aspect-ratio: 1 / 1; background: #fff; border: 1.5px dashed var(--silver-300); border-radius: 10px;
  display: flex; align-items: center; justify-content: center; margin-bottom: 13px; position: relative; overflow: hidden;
}
.qr-box svg { width: 46px; height: 46px; color: var(--silver-300); }
.qr-brand { font-size: 14px; font-weight: 600; color: var(--ink-900); margin-bottom: 3px; }
.qr-caption { font-size: 12.5px; color: var(--ink-500); margin-bottom: 0; }
.modal-alt { margin-top: 20px; text-align: center; font-size: 13.5px; color: var(--ink-500); padding-top: 20px; border-top: 1px solid var(--silver-200); }
.modal-alt a { font-weight: 600; }
.modal-note { display: flex; gap: 9px; align-items: center; justify-content: center; margin-top: 13px; font-size: 12.5px; color: var(--green-700); }
.modal-note svg { width: 15px; height: 15px; }

/* ---------- 页脚 ---------- */
.site-footer { background: var(--ink-900); color: var(--ink-400); padding: 60px 0 0; margin-top: 0; }
.footer-grid { display: grid; grid-template-columns: 1.5fr 1fr 1fr 1fr; gap: 40px; padding-bottom: 46px; }
.footer-brand .brand-name { color: #fff; }
.footer-brand .brand-sub { color: var(--ink-400); }
.footer-brand .brand-logo { filter: none; }
.footer-about { font-size: 13.5px; color: var(--ink-400); margin: 18px 0 20px; max-width: 320px; }
.footer-social { display: flex; gap: 10px; }
.footer-social a { width: 37px; height: 37px; border-radius: 9px; background: var(--ink-800); display: flex; align-items: center; justify-content: center; color: var(--ink-400); border: 1px solid var(--ink-700); }
.footer-social a:hover { background: var(--blue-600); color: #fff; border-color: var(--blue-600); }
.footer-social svg { width: 18px; height: 18px; }
.footer-title { color: #fff; font-size: 14.5px; font-weight: 600; margin-bottom: 18px; }
.footer-links { list-style: none; padding: 0; margin: 0; }
.footer-links li { margin-bottom: 11px; }
.footer-links a { color: var(--ink-400); font-size: 14px; }
.footer-links a:hover { color: #fff; }
.footer-bottom { border-top: 1px solid var(--ink-700); padding: 22px 0; font-size: 13px; }
.footer-bottom-inner { display: flex; align-items: center; justify-content: space-between; gap: 16px; flex-wrap: wrap; }
.footer-bottom a { color: var(--ink-400); }
.footer-bottom a:hover { color: #fff; }
.footer-disclaimer { font-size: 12.5px; color: var(--ink-500); padding: 0 0 26px; line-height: 1.7; }

/* ---------- 滚动揭示 ---------- */
.reveal { opacity: 0; transform: translateY(22px); transition: opacity .6s ease, transform .6s ease; }
.reveal.visible { opacity: 1; transform: none; }
.reveal.d1 { transition-delay: .07s; } .reveal.d2 { transition-delay: .14s; } .reveal.d3 { transition-delay: .21s; }

/* =====================================================================
   响应式
   ===================================================================== */
@media (max-width: 980px) {
  .hero-grid { grid-template-columns: 1fr; gap: 44px; }
  .hero-media { max-width: 560px; margin: 0 auto; width: 100%; }
  .grid-4 { grid-template-columns: repeat(2, 1fr); }
  .grid-3 { grid-template-columns: repeat(2, 1fr); }
  .footer-grid { grid-template-columns: 1fr 1fr; gap: 34px; }
  .feature-row { grid-template-columns: 1fr; gap: 30px; margin-bottom: 60px; }
  .feature-row.reverse .feature-media { order: 0; }
  .cta-band { flex-direction: column; text-align: center; padding: 42px 30px; }
}

@media (max-width: 760px) {
  .section { padding: 58px 0; }
  .nav, .header-cta { display: none; }
  .nav-toggle { display: block; }
  .nav.mobile-open {
    display: flex; flex-direction: column; align-items: stretch; gap: 4px;
    position: absolute; top: var(--header-h); left: 0; right: 0;
    background: #fff; border-bottom: 1px solid var(--silver-200); box-shadow: var(--shadow);
    padding: 14px 20px 20px; margin-left: 0;
  }
  .nav.mobile-open .nav-link { padding: 13px 14px; font-size: 16px; }
  .nav.mobile-open .header-cta { display: block; margin: 10px 0 0; }
  .nav.mobile-open .header-cta .btn { width: 100%; padding: 14px; }
  .hero { padding: 48px 0 46px; }
  .hero-stats { grid-template-columns: repeat(2, 1fr); gap: 24px; }
  .grid-3, .grid-2, .grid-4, .arch-cols, .version-grid, .qr-grid { grid-template-columns: 1fr; }
  .steps.cols-2 { grid-template-columns: 1fr; }
  .footer-grid { grid-template-columns: 1fr; gap: 32px; }
  .flow { flex-direction: column; align-items: center; gap: 10px; }
  .flow-arrow { transform: rotate(90deg); padding: 4px 0; }
  .tl-row { grid-template-columns: 110px 32px 1fr; }
  .faq-a-inner { padding-left: 22px; }
  .card { padding: 24px; }
}

@media (max-width: 420px) {
  .container { padding: 0 18px; }
  .hero-actions .btn { width: 100%; }
  .brand-sub { display: none; }
}

/* 减弱动效偏好 */
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  .reveal { opacity: 1; transform: none; transition: none; }
  * { animation-duration: .01ms !important; transition-duration: .01ms !important; }
}