/* ==========================================================================
   蓝天电脑资源检测 — 官网样式
   设计令牌与 ltyun.top (ltcloud2 主题) 完全对齐：
   主色 #5B9BD5 / 强调 #165dff / 渐变 #0080ff → #96c9ff / 白底 #333 文字 / 3px 圆角
   ========================================================================== */

:root {
  --primary: #5B9BD5;
  --primary-dark: #4a8ac4;
  --primary-light: #8bbde5;
  --accent: #165dff;
  --grad-from: #0080ff;
  --grad-to: #96c9ff;
  --sky: #87CEFA;

  --text: #333333;
  --text-muted: #6c757d;
  --text-soft: #8a94a6;

  --bg: #ffffff;
  --bg-soft: #f7fafd;
  --bg-tint: #f2f8ff;
  --border: #e9edf2;

  --radius: 3px;
  --radius-lg: 8px;

  --shadow-xs: 0 1px 2px rgba(16, 42, 74, .06);
  --shadow-sm: 0 2px 8px rgba(0, 0, 0, .08);
  --shadow-md: 0 6px 24px rgba(31, 78, 138, .10);
  --shadow-lg: 0 18px 48px rgba(31, 78, 138, .14);

  --nav-h: 72px;
  --font: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue",
          "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", Arial, sans-serif;
}

* { box-sizing: border-box; }

html { scroll-behavior: smooth; }

body {
  margin: 0;
  font-family: var(--font);
  background-color: var(--bg);
  color: var(--text);
  overflow-x: hidden;
  -webkit-font-smoothing: antialiased;
  line-height: 1.6;
}

a { color: var(--primary); text-decoration: none; }
a:hover { color: var(--accent); }

img { max-width: 100%; }

/* 图标继承文字颜色（内联 symbol 本身不带 fill，需显式声明）
   注意：仅对未显式写 fill 的图形生效，显式 fill 的元素不受影响 */
svg { fill: currentColor; }

::selection { background: rgba(91, 155, 213, .25); }

/* 滚动条 */
::-webkit-scrollbar { width: 10px; height: 10px; }
::-webkit-scrollbar-track { background: #f1f5f9; }
::-webkit-scrollbar-thumb { background: #c8d8e8; border-radius: 6px; }
::-webkit-scrollbar-thumb:hover { background: var(--primary-light); }

.container {
  width: 100%;
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 20px;
}

/* ============================== 通用 ============================== */

.section { padding: 88px 0; }
.section-tint { background: var(--bg-soft); }

.section-head { text-align: center; max-width: 760px; margin: 0 auto 52px; }

.section-title {
  font-size: 2.3rem;
  font-weight: 700;
  color: var(--text);
  margin: 0 0 14px;
  letter-spacing: -.4px;
}

.section-desc {
  font-size: 1.02rem;
  color: var(--text-muted);
  margin: 0;
}

.eyebrow {
  display: inline-flex;
  align-items: center;
  gap: 7px;
  font-size: .82rem;
  font-weight: 600;
  letter-spacing: .4px;
  color: var(--primary);
  background: rgba(91, 155, 213, .10);
  border: 1px solid rgba(91, 155, 213, .22);
  border-radius: 100px;
  padding: 6px 15px;
  margin-bottom: 18px;
}

.gradient-text {
  background: linear-gradient(90deg, var(--grad-from), var(--grad-to));
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
}

/* 按钮 */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 12px 24px;
  font-size: 1rem;
  font-weight: 600;
  font-family: inherit;
  border-radius: var(--radius);
  border: 1px solid transparent;
  cursor: pointer;
  transition: transform .2s ease, box-shadow .2s ease, background-color .2s ease,
              color .2s ease, border-color .2s ease;
  white-space: nowrap;
  text-decoration: none;
}

.btn-primary {
  background-color: var(--primary);
  color: #fff;
  box-shadow: 0 4px 14px rgba(91, 155, 213, .35);
}
.btn-primary:hover {
  background-color: var(--primary-dark);
  color: #fff;
  transform: translateY(-2px);
  box-shadow: 0 8px 22px rgba(91, 155, 213, .42);
}

.btn-gradient {
  background: linear-gradient(90deg, var(--grad-from), var(--grad-to));
  color: #fff;
  box-shadow: 0 6px 20px rgba(0, 128, 255, .30);
}
.btn-gradient:hover {
  color: #fff;
  transform: translateY(-2px);
  box-shadow: 0 10px 28px rgba(0, 128, 255, .38);
  filter: saturate(1.08);
}

.btn-outline {
  background: transparent;
  color: var(--primary);
  border-color: var(--primary);
}
.btn-outline:hover {
  background: var(--primary);
  color: #fff;
  transform: translateY(-2px);
  box-shadow: 0 8px 20px rgba(91, 155, 213, .28);
}

.btn-ghost {
  background: #fff;
  color: var(--text);
  border-color: var(--border);
  box-shadow: var(--shadow-xs);
}
.btn-ghost:hover { border-color: var(--primary-light); color: var(--primary); transform: translateY(-2px); }

.btn-lg { padding: 15px 34px; font-size: 1.06rem; }
.btn-sm { padding: 8px 16px; font-size: .88rem; }

/* ============================== 导航栏 ============================== */

.navbar {
  position: fixed;
  top: 0; left: 0; right: 0;
  height: var(--nav-h);
  background-color: #fff;
  box-shadow: 0 2px 8px rgba(0, 0, 0, .10);
  z-index: 998;
  transition: box-shadow .25s ease, background-color .25s ease;
}
.navbar.scrolled { box-shadow: 0 4px 18px rgba(16, 42, 74, .13); }

.nav-inner {
  height: var(--nav-h);
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 20px;
}

.brand { display: flex; align-items: center; gap: 11px; margin-left: 4px; }
.brand-mark { width: 38px; height: 38px; flex-shrink: 0; }
.brand-text { display: flex; flex-direction: column; line-height: 1.15; }
.brand-name { font-size: 1.06rem; font-weight: 700; color: var(--text); letter-spacing: -.2px; }
.brand-sub { font-size: .68rem; color: var(--text-soft); letter-spacing: 1.4px; text-transform: uppercase; }

.nav-menu { display: flex; align-items: center; gap: 4px; margin-left: auto; }

.nav-link {
  position: relative;
  display: flex;
  align-items: center;
  gap: 4px;
  padding: 8px 16px;
  font-size: 15px;
  font-weight: 400;
  color: var(--text);
  border-radius: 4px;
  transition: all .3s ease;
  cursor: pointer;
}
.nav-link:hover { color: var(--accent); background: rgba(22, 93, 255, .06); }

.nav-actions { display: flex; align-items: center; gap: 12px; margin-right: 4px; }

.nav-toggle {
  display: none;
  width: 40px; height: 40px;
  align-items: center;
  justify-content: center;
  background: transparent;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  color: var(--text);
  cursor: pointer;
}

/* 移动端菜单 */
.mobile-nav {
  position: fixed;
  top: var(--nav-h); left: 0; right: 0;
  background: #fff;
  border-top: 1px solid var(--border);
  box-shadow: 0 12px 28px rgba(16, 42, 74, .12);
  padding: 10px 20px 22px;
  z-index: 997;
  transform: translateY(-12px);
  opacity: 0;
  pointer-events: none;
  transition: all .28s ease;
  max-height: calc(100vh - var(--nav-h));
  overflow-y: auto;
}
.mobile-nav.open { transform: translateY(0); opacity: 1; pointer-events: auto; }
.mobile-nav a {
  display: block;
  padding: 13px 4px;
  color: var(--text);
  font-size: 15px;
  border-bottom: 1px solid var(--border);
}
.mobile-nav a:last-of-type { border-bottom: none; }
.mobile-nav .btn { width: 100%; margin-top: 16px; }

/* ============================== Hero ============================== */

.hero {
  position: relative;
  padding: calc(var(--nav-h) + 78px) 0 92px;
  background:
    radial-gradient(900px 480px at 12% 4%, rgba(0, 128, 255, .13), transparent 62%),
    radial-gradient(760px 420px at 88% 12%, rgba(150, 201, 255, .22), transparent 60%),
    linear-gradient(180deg, #f2f8ff 0%, #ffffff 68%);
  overflow: hidden;
}

.hero::before {
  content: "";
  position: absolute;
  inset: 0;
  background-image:
    linear-gradient(rgba(91, 155, 213, .075) 1px, transparent 1px),
    linear-gradient(90deg, rgba(91, 155, 213, .075) 1px, transparent 1px);
  background-size: 46px 46px;
  -webkit-mask-image: radial-gradient(ellipse 78% 62% at 50% 22%, #000 30%, transparent 78%);
  mask-image: radial-gradient(ellipse 78% 62% at 50% 22%, #000 30%, transparent 78%);
  pointer-events: none;
}

.hero-glow {
  position: absolute;
  border-radius: 50%;
  filter: blur(72px);
  opacity: .5;
  pointer-events: none;
  animation: floaty 14s ease-in-out infinite;
}
.hero-glow.g1 { width: 340px; height: 340px; background: rgba(0, 128, 255, .28); top: -70px; left: -60px; }
.hero-glow.g2 { width: 300px; height: 300px; background: rgba(150, 201, 255, .42); bottom: -80px; right: -40px; animation-delay: -6s; }

@keyframes floaty {
  0%, 100% { transform: translate3d(0, 0, 0) scale(1); }
  50% { transform: translate3d(22px, -26px, 0) scale(1.07); }
}

.hero-inner {
  position: relative;
  z-index: 2;
  display: grid;
  grid-template-columns: 1.06fr .94fr;
  gap: 56px;
  align-items: center;
}

.hero-title {
  font-size: 3.35rem;
  font-weight: 800;
  line-height: 1.14;
  letter-spacing: -1.4px;
  margin: 0 0 20px;
  color: var(--text);
}
.hero-title .gradient-text { display: inline-block; }

.hero-subtitle {
  font-size: 1.16rem;
  color: var(--text-muted);
  margin: 0 0 14px;
  max-width: 620px;
}

.hero-typing {
  min-height: 30px;
  font-size: 1.02rem;
  font-weight: 600;
  color: #00C4FF;
  margin: 0 0 26px;
  display: flex;
  align-items: center;
  gap: 2px;
}
.hero-typing .caret {
  display: inline-block;
  width: 2px; height: 1.05em;
  background: #00C4FF;
  animation: blink 1s step-end infinite;
  vertical-align: -2px;
}
@keyframes blink { 0%, 100% { opacity: 1; } 50% { opacity: 0; } }

.hero-btns { display: flex; flex-wrap: wrap; gap: 14px; margin-bottom: 26px; }

.hero-badges { display: flex; flex-wrap: wrap; gap: 10px 22px; }
.hero-badge {
  display: inline-flex;
  align-items: center;
  gap: 7px;
  font-size: .88rem;
  color: var(--text-muted);
  font-weight: 500;
}
.hero-badge svg { color: var(--primary); flex-shrink: 0; }

/* Hero 右侧：面板预览 */
.preview-wrap { position: relative; }

.preview-card {
  position: relative;
  background: #fff;
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-lg);
  overflow: hidden;
  animation: rise .9s cubic-bezier(.22, 1, .36, 1) both;
}

@keyframes rise {
  from { opacity: 0; transform: translateY(26px) scale(.98); }
  to { opacity: 1; transform: translateY(0) scale(1); }
}

.preview-bar {
  display: flex;
  align-items: center;
  gap: 8px;
  padding: 12px 16px;
  background: #f7fafd;
  border-bottom: 1px solid var(--border);
}
.preview-dot { width: 11px; height: 11px; border-radius: 50%; }
.preview-dot.r { background: #ff5f57; }
.preview-dot.y { background: #febc2e; }
.preview-dot.g { background: #28c840; }
.preview-url {
  margin-left: 10px;
  flex: 1;
  font-size: .76rem;
  color: var(--text-soft);
  background: #fff;
  border: 1px solid var(--border);
  border-radius: 100px;
  padding: 4px 12px;
  font-family: ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
  overflow: hidden;
  white-space: nowrap;
  text-overflow: ellipsis;
}

.preview-body { padding: 20px; }

.gauge-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 14px; margin-bottom: 16px; }

.gauge {
  background: #fbfdff;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 14px 12px;
  text-align: center;
}
.gauge-ring { position: relative; width: 74px; height: 74px; margin: 0 auto 8px; }
.gauge-ring svg { transform: rotate(-90deg); display: block; }
.gauge-ring .track { stroke: #e9eff6; }
.gauge-ring .val { stroke-linecap: round; transition: stroke-dashoffset 1.4s cubic-bezier(.22, 1, .36, 1); }
.gauge-num {
  position: absolute; inset: 0;
  display: flex; align-items: center; justify-content: center;
  font-size: .95rem; font-weight: 700; color: var(--text);
}
.gauge-label { font-size: .76rem; color: var(--text-muted); }

.preview-list { border-top: 1px dashed var(--border); padding-top: 14px; }
.preview-row {
  display: flex; align-items: center; gap: 10px;
  padding: 8px 2px;
  font-size: .82rem;
  color: var(--text-muted);
}
.preview-row .pname { flex: 1; color: var(--text); font-weight: 500; overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }
.preview-row .pbar { width: 88px; height: 6px; background: #eef3f9; border-radius: 100px; overflow: hidden; }
.preview-row .pbar i { display: block; height: 100%; border-radius: 100px; background: linear-gradient(90deg, var(--grad-from), var(--grad-to)); }
.preview-row .pval { width: 40px; text-align: right; font-variant-numeric: tabular-nums; }

.preview-float {
  position: absolute;
  background: #fff;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  box-shadow: var(--shadow-md);
  padding: 10px 14px;
  font-size: .8rem;
  display: flex;
  align-items: center;
  gap: 9px;
  font-weight: 600;
  color: var(--text);
}
.preview-float small { display: block; font-weight: 400; color: var(--text-soft); font-size: .72rem; }
.preview-float.f1 { top: -56px; left: 50%; translate: -50% 0; animation: bob 5.5s ease-in-out infinite; }
.preview-float.f2 { bottom: -56px; left: 50%; translate: -50% 0; animation: bob 5.5s ease-in-out infinite -2.6s; }
@keyframes bob { 0%, 100% { transform: translateY(0); } 50% { transform: translateY(-9px); } }

/* ============================== 特性卡 ============================== */

.grid { display: grid; gap: 22px; }
.grid-4 { grid-template-columns: repeat(4, 1fr); }
.grid-3 { grid-template-columns: repeat(3, 1fr); }
.grid-2 { grid-template-columns: repeat(2, 1fr); }

.card {
  background: #fff;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 26px 24px;
  transition: transform .28s ease, box-shadow .28s ease, border-color .28s ease;
}
.card:hover { transform: translateY(-5px); box-shadow: var(--shadow-md); border-color: rgba(91, 155, 213, .38); }

.feature-card { text-align: left; }

.feature-icon {
  width: 52px; height: 52px;
  display: flex; align-items: center; justify-content: center;
  border-radius: var(--radius);
  margin-bottom: 16px;
}
.feature-icon svg { width: 24px; height: 24px; }

.ic-blue   { background: rgba(91, 155, 213, .13); color: #2f7ec4; }
.ic-green  { background: rgba(40, 167, 69, .12);  color: #218838; }
.ic-amber  { background: rgba(255, 159, 0, .14);  color: #c47f00; }
.ic-cyan   { background: rgba(0, 196, 255, .13);  color: #0091c2; }
.ic-purple { background: rgba(122, 92, 240, .12); color: #6746e0; }
.ic-red    { background: rgba(220, 53, 69, .11);  color: #c82333; }

.feature-card h3, .feature-card h4 {
  font-size: 1.1rem;
  font-weight: 600;
  color: var(--text);
  margin: 0 0 8px;
}
.feature-card p { font-size: .93rem; color: var(--text-muted); margin: 0; line-height: 1.68; }

.card-tag {
  display: inline-block;
  font-size: .7rem;
  font-weight: 700;
  letter-spacing: .5px;
  color: var(--primary);
  background: rgba(91, 155, 213, .12);
  border-radius: 3px;
  padding: 3px 8px;
  margin-bottom: 12px;
}

/* ============================== 数据统计 ============================== */

.stats-band {
  background: linear-gradient(115deg, #0b4a86 0%, #1565a8 46%, #2f8fd0 100%);
  position: relative;
  overflow: hidden;
  color: #fff;
}
.stats-band::before {
  content: "";
  position: absolute; inset: 0;
  background-image:
    linear-gradient(rgba(255, 255, 255, .07) 1px, transparent 1px),
    linear-gradient(90deg, rgba(255, 255, 255, .07) 1px, transparent 1px);
  background-size: 44px 44px;
}
.stats-band::after {
  content: "";
  position: absolute;
  width: 520px; height: 520px;
  border-radius: 50%;
  background: radial-gradient(circle, rgba(150, 201, 255, .38), transparent 66%);
  top: -220px; right: -120px;
}
.stats-inner { position: relative; z-index: 2; padding: 62px 0; }
.stats-grid { display: grid; grid-template-columns: repeat(4, 1fr); gap: 26px; text-align: center; }
.stat-num {
  font-size: 2.55rem;
  font-weight: 800;
  line-height: 1;
  letter-spacing: -1px;
  font-variant-numeric: tabular-nums;
  margin-bottom: 10px;
}
.stat-num .suffix { font-size: 1.35rem; font-weight: 700; margin-left: 3px; }
.stat-label { font-size: .93rem; color: rgba(255, 255, 255, .82); }

/* ============================== 环境支持 ============================== */

.env-chips { display: flex; flex-wrap: wrap; justify-content: center; gap: 12px; margin-bottom: 22px; }
.chip {
  display: inline-flex; align-items: center; gap: 8px;
  background: #fff;
  border: 1px solid var(--border);
  border-radius: 100px;
  padding: 10px 20px;
  font-size: .9rem;
  font-weight: 600;
  color: var(--text);
  box-shadow: var(--shadow-xs);
  transition: all .25s ease;
}
.chip:hover { border-color: var(--primary-light); color: var(--primary); transform: translateY(-3px); box-shadow: var(--shadow-sm); }
.chip svg { color: var(--primary); }
.env-note { text-align: center; color: var(--text-soft); font-size: .9rem; }

/* ============================== 下载区 ============================== */

.download-band {
  position: relative;
  background:
    radial-gradient(700px 380px at 18% 0%, rgba(0, 128, 255, .10), transparent 62%),
    radial-gradient(620px 340px at 88% 100%, rgba(150, 201, 255, .24), transparent 60%),
    var(--bg-soft);
  overflow: hidden;
}

.download-card {
  position: relative;
  background: #fff;
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-lg);
  padding: 46px 44px;
  display: grid;
  grid-template-columns: 1.25fr .75fr;
  gap: 44px;
  align-items: center;
}

.download-card h2 { font-size: 2rem; font-weight: 700; margin: 0 0 12px; letter-spacing: -.5px; }
.download-card > div > p { color: var(--text-muted); margin: 0 0 24px; }

.dl-meta { display: flex; flex-wrap: wrap; gap: 10px 26px; margin-bottom: 26px; }
.dl-meta span { display: inline-flex; align-items: center; gap: 7px; font-size: .88rem; color: var(--text-muted); }
.dl-meta span b { color: var(--text); font-weight: 600; }
.dl-meta svg { color: var(--primary); }

.dl-actions { display: flex; flex-wrap: wrap; gap: 14px; }

.dl-hint { margin-top: 16px; font-size: .82rem; color: var(--text-soft); }

.dl-side {
  background: linear-gradient(160deg, #f4f9ff, #eaf4ff);
  border: 1px solid rgba(91, 155, 213, .22);
  border-radius: var(--radius);
  padding: 26px 24px;
}
.dl-side h4 { margin: 0 0 16px; font-size: .95rem; color: var(--text); font-weight: 700; }
.dl-steps { list-style: none; margin: 0; padding: 0; counter-reset: s; }
.dl-steps li {
  position: relative;
  padding-left: 32px;
  margin-bottom: 14px;
  font-size: .88rem;
  color: var(--text-muted);
  counter-increment: s;
}
.dl-steps li:last-child { margin-bottom: 0; }
.dl-steps li::before {
  content: counter(s);
  position: absolute; left: 0; top: 1px;
  width: 21px; height: 21px;
  display: flex; align-items: center; justify-content: center;
  background: var(--primary);
  color: #fff;
  border-radius: 50%;
  font-size: .7rem;
  font-weight: 700;
}

/* ============================== FAQ ============================== */

.faq-list { max-width: 860px; margin: 0 auto; }
.faq-item {
  background: #fff;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  margin-bottom: 12px;
  overflow: hidden;
  transition: box-shadow .25s ease, border-color .25s ease;
}
.faq-item:hover { border-color: rgba(91, 155, 213, .38); }
.faq-item.open { box-shadow: var(--shadow-sm); border-color: rgba(91, 155, 213, .45); }

.faq-q {
  width: 100%;
  display: flex;
  align-items: center;
  gap: 14px;
  padding: 19px 22px;
  background: transparent;
  border: none;
  font-family: inherit;
  font-size: 1rem;
  font-weight: 600;
  color: var(--text);
  text-align: left;
  cursor: pointer;
}
.faq-q .qmark { color: var(--primary); flex-shrink: 0; display: flex; }
.faq-q .arrow { margin-left: auto; color: var(--text-soft); transition: transform .3s ease; flex-shrink: 0; display: flex; }
.faq-item.open .faq-q .arrow { transform: rotate(180deg); color: var(--primary); }

.faq-a { max-height: 0; overflow: hidden; transition: max-height .34s ease; }
.faq-a-inner {
  padding: 0 22px 20px 58px;
  color: var(--text-muted);
  font-size: .93rem;
  line-height: 1.75;
}

/* 主下载按钮上的「外部」角标（↗） */
.btn .dl-badge {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  margin-left: 8px;
  width: 18px;
  height: 18px;
  font-size: 12px;
  font-weight: 700;
  color: #fff;
  background: rgba(255, 255, 255, .22);
  border-radius: 50%;
  line-height: 1;
}
code {
  background: #f2f6fb;
  border: 1px solid var(--border);
  border-radius: 3px;
  padding: 1px 6px;
  font-size: .86em;
  color: #2f7ec4;
  font-family: ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
  word-break: break-all;
}

/* ============================== 页脚 ============================== */

.footer { background: #0e2136; color: rgba(255, 255, 255, .72); padding: 60px 0 0; }
.footer-grid { display: grid; grid-template-columns: 1.6fr 1fr 1fr 1fr; gap: 36px; padding-bottom: 40px; }
.footer h5 { color: #fff; font-size: .95rem; font-weight: 700; margin: 0 0 16px; letter-spacing: .3px; }
.footer-brand { display: flex; align-items: center; gap: 11px; margin-bottom: 16px; }
.footer-brand .brand-name { color: #fff; }
.footer-brand .brand-sub { color: rgba(255, 255, 255, .5); }
.footer p { font-size: .88rem; line-height: 1.75; margin: 0 0 14px; }
.footer-links { list-style: none; margin: 0; padding: 0; }
.footer-links li { margin-bottom: 11px; }
.footer-links a { color: rgba(255, 255, 255, .72); font-size: .88rem; transition: color .2s ease; }
.footer-links a:hover { color: #fff; }

.footer-bottom {
  border-top: 1px solid rgba(255, 255, 255, .10);
  padding: 22px 0;
  display: flex;
  flex-wrap: wrap;
  gap: 10px 20px;
  align-items: center;
  justify-content: space-between;
  font-size: .83rem;
  color: rgba(255, 255, 255, .55);
}
.footer-bottom a { color: rgba(255, 255, 255, .7); }
.footer-bottom a:hover { color: #fff; }

/* ============================== 回到顶部 ============================== */

.to-top {
  position: fixed;
  right: 26px; bottom: 26px;
  width: 46px; height: 46px;
  display: flex; align-items: center; justify-content: center;
  background: #fff;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  color: var(--primary);
  box-shadow: var(--shadow-md);
  cursor: pointer;
  opacity: 0;
  transform: translateY(14px);
  pointer-events: none;
  transition: all .3s ease;
  z-index: 900;
}
.to-top.show { opacity: 1; transform: translateY(0); pointer-events: auto; }
.to-top:hover { background: var(--primary); color: #fff; border-color: var(--primary); }

/* ============================== 滚动动效 ============================== */

/* 用独立的 translate 属性做进场位移，与 .card:hover 的 transform 互不冲突。
   注意：隐藏态挂在 .js 之下 —— 禁用 JS 时元素默认可见，不会整页空白。
   （<head> 里有一段内联脚本给 <html> 加上 .js 类） */
.js .reveal {
  opacity: 0;
  translate: 0 26px;
  transition: opacity .7s ease, translate .7s cubic-bezier(.22, 1, .36, 1);
}
.js .reveal.visible { opacity: 1; translate: 0 0; }

/* 卡片/手风琴自身也有 hover 过渡，合并 transition 列表避免被覆盖 */
.js .card.reveal,
.js .faq-item.reveal {
  transition: opacity .7s ease, translate .7s cubic-bezier(.22, 1, .36, 1),
              transform .28s ease, box-shadow .28s ease, border-color .28s ease;
}

@media (prefers-reduced-motion: reduce) {
  * { animation-duration: .001ms !important; transition-duration: .001ms !important; }
  .js .reveal { opacity: 1; translate: none; }
  html { scroll-behavior: auto; }
}

/* ============================== 响应式 ============================== */

@media (max-width: 1080px) {
  .hero-inner { grid-template-columns: 1fr; gap: 46px; }
  .hero-title { font-size: 2.85rem; }
  .hero { padding-top: calc(var(--nav-h) + 56px); }
  .preview-float.f1 { top: -46px; }
  .preview-float.f2 { bottom: -46px; }
  .download-card { grid-template-columns: 1fr; gap: 30px; padding: 36px 30px; }
}

@media (max-width: 960px) {
  .nav-menu, .nav-actions .btn-nav-desktop { display: none; }
  .nav-toggle { display: flex; }
  .grid-4 { grid-template-columns: repeat(2, 1fr); }
  .grid-3 { grid-template-columns: repeat(2, 1fr); }
  .stats-grid { grid-template-columns: repeat(2, 1fr); gap: 34px 20px; }
  .footer-grid { grid-template-columns: 1fr 1fr; gap: 30px; }
}

@media (max-width: 680px) {
  .section { padding: 62px 0; }
  .section-title { font-size: 1.72rem; }
  .hero-title { font-size: 2.15rem; letter-spacing: -.8px; }
  .hero-subtitle { font-size: 1.02rem; }
  .grid-4, .grid-3, .grid-2 { grid-template-columns: 1fr; }
  .gauge-grid { grid-template-columns: 1fr; }
  .preview-float { display: none; }
  .footer-grid { grid-template-columns: 1fr; }
  .footer-bottom { justify-content: center; text-align: center; }
  .to-top { right: 16px; bottom: 16px; }
  .btn-lg { padding: 14px 24px; font-size: 1rem; }
  .hero-btns .btn { width: 100%; }
}