/* =========================================================
   掌上节拍器 · 静态下载站样式
   响应式：桌面 / 平板 / 手机
   ========================================================= */

:root {
  --blue-900: #062a5e;
  --blue-800: #0b3d86;
  --blue-700: #1655ac;
  --blue-600: #1f6fe0;
  --blue-500: #2f86f6;
  --sky-400: #56b3ff;
  --sky-300: #8fd0ff;
  --ink-900: #0b1220;
  --ink-800: #131c2e;
  --ink-700: #1d2739;
  --ink-500: #4a5568;
  --ink-400: #6b7688;
  --ink-200: #e3e8f0;
  --ink-100: #f2f5fa;
  --white: #ffffff;
  --radius-sm: 10px;
  --radius: 16px;
  --radius-lg: 24px;
  --radius-xl: 32px;
  --shadow-sm: 0 4px 14px rgba(11, 31, 68, .06);
  --shadow: 0 12px 34px rgba(11, 31, 68, .10);
  --shadow-lg: 0 26px 60px rgba(11, 31, 68, .16);
  --header-h: 68px;
  --ease: cubic-bezier(.22, .61, .36, 1);
}

* { box-sizing: border-box; }

html {
  scroll-behavior: smooth;
  scroll-padding-top: calc(var(--header-h) + 12px);
  -webkit-text-size-adjust: 100%;
}

body {
  margin: 0;
  font-family: "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "Helvetica Neue", Helvetica, Arial, system-ui, sans-serif;
  color: var(--ink-700);
  background: var(--white);
  line-height: 1.7;
  font-size: 16px;
  overflow-x: hidden;
}

img { max-width: 100%; display: block; height: auto; }

a { color: inherit; text-decoration: none; }

h1, h2, h3, h4 {
  color: var(--ink-900);
  line-height: 1.25;
  margin: 0 0 .5em;
  letter-spacing: -.01em;
}

h1 { font-size: clamp(2rem, 5.2vw, 3.5rem); font-weight: 800; }
h2 { font-size: clamp(1.5rem, 3.6vw, 2.35rem); font-weight: 800; }
h3 { font-size: clamp(1.05rem, 1.7vw, 1.3rem); font-weight: 700; }
p { margin: 0 0 1em; }

.container {
  width: 100%;
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 24px;
}

/* ---------------- 按钮 ---------------- */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 12px 22px;
  border: 1px solid transparent;
  border-radius: 999px;
  font-size: .95rem;
  font-weight: 600;
  cursor: pointer;
  transition: transform .25s var(--ease), box-shadow .25s var(--ease), background .25s, color .25s, border-color .25s;
  white-space: nowrap;
}
.btn svg { width: 18px; height: 18px; }
.btn-lg { padding: 15px 30px; font-size: 1rem; }
.btn-primary {
  background: linear-gradient(135deg, var(--blue-600), var(--sky-400));
  color: #fff;
  box-shadow: 0 10px 26px rgba(31, 111, 224, .32);
}
.btn-primary:hover { transform: translateY(-2px); box-shadow: 0 16px 34px rgba(31, 111, 224, .4); }
.btn-ghost {
  background: rgba(255, 255, 255, .12);
  color: #fff;
  border-color: rgba(255, 255, 255, .38);
  backdrop-filter: blur(6px);
}
.btn-ghost:hover { background: rgba(255, 255, 255, .22); transform: translateY(-2px); }
.btn-outline {
  background: #fff;
  color: var(--blue-700);
  border-color: rgba(31, 111, 224, .35);
}
.btn-outline:hover { border-color: var(--blue-600); transform: translateY(-2px); }
.btn-light { background: #fff; color: var(--blue-800); box-shadow: 0 12px 28px rgba(0, 0, 0, .18); }
.btn-light:hover { transform: translateY(-2px); }

/* ---------------- 顶部导航 ---------------- */
.site-header {
  position: fixed;
  inset: 0 0 auto 0;
  z-index: 100;
  height: var(--header-h);
  display: flex;
  align-items: center;
  transition: background .3s, box-shadow .3s, backdrop-filter .3s, height .3s;
}
.site-header.scrolled {
  background: rgba(9, 26, 54, .78);
  backdrop-filter: blur(14px) saturate(150%);
  box-shadow: 0 6px 26px rgba(4, 18, 42, .28);
}
.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 18px;
  height: 100%;
}

.logo { display: inline-flex; align-items: center; gap: 10px; font-weight: 800; color: #fff; font-size: 1.06rem; }
.logo-mark {
  width: 34px; height: 34px; flex: none;
  display: grid; place-items: center;
  border-radius: 10px;
  background: linear-gradient(135deg, var(--sky-400), var(--blue-700));
  color: #fff;
  box-shadow: 0 6px 16px rgba(47, 134, 246, .42);
}
.logo-mark svg { width: 20px; height: 20px; }
.logo-text { letter-spacing: .02em; }

.main-nav { display: flex; align-items: center; gap: 26px; }
.main-nav ul { display: flex; align-items: center; gap: 4px; list-style: none; margin: 0; padding: 0; }
.nav-link {
  position: relative;
  display: inline-block;
  padding: 8px 12px;
  font-size: .93rem;
  font-weight: 500;
  color: rgba(255, 255, 255, .84);
  border-radius: 8px;
  transition: color .2s, background .2s;
}
.nav-link:hover { color: #fff; background: rgba(255, 255, 255, .1); }
.nav-link.active { color: #fff; }
.nav-link.active::after {
  content: "";
  position: absolute;
  left: 12px; right: 12px; bottom: 2px;
  height: 2px;
  border-radius: 2px;
  background: linear-gradient(90deg, var(--sky-400), var(--sky-300));
}
.btn-nav { padding: 10px 20px; font-size: .9rem; }

.nav-toggle {
  display: none;
  width: 42px; height: 42px;
  border: 0; padding: 0;
  border-radius: 12px;
  background: rgba(255, 255, 255, .12);
  cursor: pointer;
  position: relative;
}
.nav-toggle span {
  display: block;
  width: 19px; height: 2px;
  margin: 4px auto;
  border-radius: 2px;
  background: #fff;
  transition: transform .3s var(--ease), opacity .2s;
}
.nav-toggle.open span:nth-child(1) { transform: translateY(6px) rotate(45deg); }
.nav-toggle.open span:nth-child(2) { opacity: 0; }
.nav-toggle.open span:nth-child(3) { transform: translateY(-6px) rotate(-45deg); }

/* ---------------- 首屏 ---------------- */
.hero {
  position: relative;
  overflow: hidden;
  padding: calc(var(--header-h) + 64px) 0 84px;
  background:
    radial-gradient(1100px 620px at 78% 12%, rgba(86, 179, 255, .38), transparent 62%),
    radial-gradient(760px 520px at 8% 88%, rgba(31, 111, 224, .34), transparent 66%),
    linear-gradient(160deg, #071a38 0%, #0b2f66 48%, #12508f 100%);
  color: rgba(255, 255, 255, .9);
}
.hero::after {
  content: "";
  position: absolute; inset: auto 0 -1px 0; height: 90px;
  background: linear-gradient(180deg, transparent, rgba(6, 20, 44, .55));
  pointer-events: none;
}
.hero-glow { position: absolute; border-radius: 50%; filter: blur(70px); pointer-events: none; }
.hero-glow-1 { width: 420px; height: 420px; top: -120px; right: -80px; background: rgba(86, 179, 255, .38); }
.hero-glow-2 { width: 360px; height: 360px; bottom: -140px; left: -90px; background: rgba(31, 111, 224, .34); }

.hero-inner {
  position: relative;
  z-index: 1;
  display: grid;
  grid-template-columns: 1.05fr .95fr;
  gap: 56px;
  align-items: center;
}
.hero h1 { color: #fff; margin-bottom: .55em; }
.grad-text {
  background: linear-gradient(100deg, #9fd8ff, #56b3ff 55%, #a7e3ff);
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
}
.eyebrow {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  margin: 0 0 20px;
  padding: 6px 14px;
  font-size: .82rem;
  font-weight: 600;
  letter-spacing: .04em;
  color: #cfeaff;
  background: rgba(255, 255, 255, .1);
  border: 1px solid rgba(255, 255, 255, .2);
  border-radius: 999px;
}
.hero-desc { font-size: clamp(.98rem, 1.3vw, 1.08rem); color: rgba(255, 255, 255, .84); max-width: 34em; }
.hero-actions { display: flex; flex-wrap: wrap; gap: 14px; margin: 30px 0 34px; }

.hero-meta {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 16px;
  list-style: none;
  margin: 0;
  padding: 22px 0 0;
  border-top: 1px solid rgba(255, 255, 255, .16);
  max-width: 460px;
}
.hero-meta li { display: flex; flex-direction: column; }
.hero-meta strong { font-size: clamp(1.25rem, 2.4vw, 1.6rem); color: #fff; font-weight: 800; }
.hero-meta span { font-size: .82rem; color: rgba(255, 255, 255, .68); }

.hero-visual { position: relative; display: flex; justify-content: center; }
.phone-frame {
  width: min(330px, 78%);
  padding: 12px;
  border-radius: 40px;
  background: linear-gradient(160deg, rgba(255, 255, 255, .28), rgba(255, 255, 255, .06));
  border: 1px solid rgba(255, 255, 255, .3);
  box-shadow: 0 40px 80px rgba(2, 14, 34, .55), inset 0 1px 0 rgba(255, 255, 255, .45);
  backdrop-filter: blur(8px);
  animation: floatY 6s ease-in-out infinite;
}
.phone-frame img { border-radius: 30px; width: 100%; }
@keyframes floatY {
  0%, 100% { transform: translateY(0); }
  50% { transform: translateY(-14px); }
}

.float-card {
  position: absolute;
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 10px 16px;
  font-size: .82rem;
  font-weight: 600;
  color: #0b2246;
  background: rgba(255, 255, 255, .92);
  border-radius: 999px;
  box-shadow: var(--shadow-lg);
  animation: floatY 5s ease-in-out infinite .8s;
}
.float-card .dot { width: 8px; height: 8px; border-radius: 50%; background: #2f86f6; box-shadow: 0 0 0 4px rgba(47, 134, 246, .22); }
.float-card .dot-alt { background: #22c55e; box-shadow: 0 0 0 4px rgba(34, 197, 94, .22); }
.float-card-a { top: 16%; left: -6%; }
.float-card-b { bottom: 14%; right: -4%; animation-delay: 1.6s; }

/* ---------------- 通用 section ---------------- */
.section { padding: clamp(64px, 9vw, 110px) 0; }
.section-alt { background: linear-gradient(180deg, var(--ink-100), #e8eef7); }
.section-head { max-width: 720px; margin: 0 auto clamp(38px, 5vw, 60px); text-align: center; }
.section-tag {
  display: inline-block;
  margin: 0 0 14px;
  padding: 5px 14px;
  font-size: .78rem;
  font-weight: 700;
  letter-spacing: .12em;
  color: var(--blue-700);
  background: rgba(31, 111, 224, .1);
  border-radius: 999px;
}
.section-alt .section-tag { background: rgba(31, 111, 224, .14); }
.section-sub { color: var(--ink-500); margin: 0; }

/* ---------------- 节拍器展示 ---------------- */
.showcase-grid {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: clamp(20px, 2.6vw, 32px);
}
.showcase-card {
  position: relative;
  display: flex;
  flex-direction: column;
  background: #fff;
  border: 1px solid var(--ink-200);
  border-radius: var(--radius-lg);
  overflow: hidden;
  box-shadow: var(--shadow-sm);
  transition: transform .35s var(--ease), box-shadow .35s var(--ease), border-color .35s;
}
.showcase-card:hover { transform: translateY(-8px); box-shadow: var(--shadow-lg); border-color: rgba(31, 111, 224, .3); }
.showcase-media {
  padding: 26px 26px 0;
  background:
    radial-gradient(520px 260px at 50% 0%, rgba(86, 179, 255, .35), transparent 70%),
    linear-gradient(165deg, #0c2c5e, #1655ac);
}
.showcase-media img {
  width: 100%;
  border-radius: 14px 14px 0 0;
  box-shadow: 0 22px 40px rgba(3, 16, 38, .38);
  transition: transform .45s var(--ease);
}
.showcase-card:hover .showcase-media img { transform: translateY(-6px) scale(1.02); }
.showcase-body { padding: 24px 26px 30px; }
.showcase-body h3 { margin-bottom: .35em; }
.showcase-body p { margin: 0; color: var(--ink-500); font-size: .94rem; }

/* ---------------- 节拍器介绍 ---------------- */
.intro-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: clamp(36px, 5vw, 72px);
  align-items: start;
}
.intro-copy p { color: var(--ink-500); }
.intro-copy strong { color: var(--ink-900); }
.intro-copy .btn { margin-top: 12px; }

.check-list { list-style: none; margin: 22px 0 26px; padding: 0; }
.check-list li {
  position: relative;
  padding-left: 32px;
  margin-bottom: 12px;
  font-weight: 500;
  color: var(--ink-700);
}
.check-list li::before {
  content: "";
  position: absolute;
  left: 0; top: .45em;
  width: 20px; height: 20px;
  border-radius: 50%;
  background: linear-gradient(135deg, var(--blue-600), var(--sky-400));
  box-shadow: 0 4px 12px rgba(31, 111, 224, .35);
}
.check-list li::after {
  content: "";
  position: absolute;
  left: 6px; top: .78em;
  width: 8px; height: 4px;
  border-left: 2px solid #fff;
  border-bottom: 2px solid #fff;
  transform: rotate(-45deg);
}

.intro-cards { display: grid; grid-template-columns: 1fr 1fr; gap: 18px; }
.info-card {
  padding: 26px 24px;
  background: #fff;
  border-radius: var(--radius);
  border: 1px solid var(--ink-200);
  box-shadow: var(--shadow-sm);
  transition: transform .3s var(--ease), box-shadow .3s var(--ease);
}
.info-card:hover { transform: translateY(-6px); box-shadow: var(--shadow); }
.info-num {
  font-size: 1.05rem;
  font-weight: 800;
  color: var(--sky-400);
  letter-spacing: .06em;
  margin-bottom: 10px;
}
.info-card h4 { margin: 0 0 .4em; font-size: 1.08rem; }
.info-card p { margin: 0; font-size: .9rem; color: var(--ink-500); }

/* ---------------- 节拍器特点 ---------------- */
.feature-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: clamp(18px, 2.2vw, 26px);
}
.feature-card {
  padding: 32px 28px;
  background: #fff;
  border: 1px solid var(--ink-200);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-sm);
  transition: transform .32s var(--ease), box-shadow .32s var(--ease), border-color .32s;
}
.feature-card:hover { transform: translateY(-8px); box-shadow: var(--shadow-lg); border-color: rgba(31, 111, 224, .3); }
.feature-icon {
  width: 52px; height: 52px;
  display: grid; place-items: center;
  margin-bottom: 18px;
  border-radius: 14px;
  color: var(--blue-700);
  background: linear-gradient(135deg, rgba(86, 179, 255, .22), rgba(31, 111, 224, .16));
  border: 1px solid rgba(31, 111, 224, .18);
}
.feature-icon svg { width: 26px; height: 26px; }
.feature-card h3 { font-size: 1.12rem; }
.feature-card p { margin: 0; font-size: .92rem; color: var(--ink-500); }

/* ---------------- 用户评价 ---------------- */
.review-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(270px, 1fr));
  gap: clamp(18px, 2.2vw, 26px);
}
.review-card {
  display: flex;
  flex-direction: column;
  padding: 28px 26px;
  background: #fff;
  border: 1px solid var(--ink-200);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-sm);
  transition: transform .32s var(--ease), box-shadow .32s var(--ease);
}
.review-card:hover { transform: translateY(-6px); box-shadow: var(--shadow); }
.stars { color: #ffb020; font-size: .95rem; letter-spacing: 2px; margin-bottom: 12px; }
.review-text { flex: 1; margin: 0 0 20px; font-size: .94rem; color: var(--ink-500); }
.review-user { display: flex; align-items: center; gap: 12px; padding-top: 18px; border-top: 1px solid var(--ink-200); }
.avatar {
  width: 44px; height: 44px; flex: none;
  display: grid; place-items: center;
  border-radius: 50%;
  font-weight: 700; color: #fff;
  background: linear-gradient(135deg, var(--blue-600), var(--sky-400));
  box-shadow: 0 6px 16px rgba(31, 111, 224, .3);
}
.review-user strong { display: block; font-size: .95rem; color: var(--ink-900); }
.review-user span { font-size: .8rem; color: var(--ink-400); }

/* ---------------- 下载帮助 ---------------- */
.download-layout {
  display: grid;
  grid-template-columns: 1.25fr .75fr;
  gap: clamp(28px, 4vw, 56px);
  align-items: start;
}
.step { display: flex; gap: 18px; padding-bottom: 26px; position: relative; }
.step:not(:last-of-type)::before {
  content: "";
  position: absolute;
  left: 23px; top: 52px; bottom: 6px;
  width: 2px;
  background: linear-gradient(180deg, rgba(31, 111, 224, .4), rgba(31, 111, 224, .05));
}
.step-num {
  width: 46px; height: 46px; flex: none;
  display: grid; place-items: center;
  border-radius: 14px;
  font-weight: 800;
  color: #fff;
  background: linear-gradient(135deg, var(--blue-600), var(--sky-400));
  box-shadow: 0 8px 20px rgba(31, 111, 224, .32);
}
.step-body h3 { margin-bottom: .3em; font-size: 1.1rem; }
.step-body p { margin: 0; font-size: .93rem; color: var(--ink-500); }
.steps .hero-actions { margin: 8px 0 0; }

.download-card {
  padding: 34px 30px;
  text-align: center;
  color: rgba(255, 255, 255, .88);
  border-radius: var(--radius-lg);
  background:
    radial-gradient(420px 220px at 50% 0%, rgba(86, 179, 255, .34), transparent 70%),
    linear-gradient(160deg, #0a2449, #12508f);
  box-shadow: var(--shadow-lg);
}
.download-card h3 { color: #fff; margin: 22px 0 .3em; }
.download-card p { font-size: .89rem; color: rgba(255, 255, 255, .72); }
.qr-box {
  width: 168px; height: 168px;
  margin: 0 auto;
  display: grid; place-items: center;
  background: #fff;
  border-radius: var(--radius);
  box-shadow: 0 18px 34px rgba(3, 16, 38, .35);
}
.qr-grid {
  display: grid;
  grid-template-columns: repeat(5, 1fr);
  gap: 5px;
  width: 116px; height: 116px;
}
.qr-grid span { border-radius: 3px; background: #dbe4f0; }
.qr-grid span:nth-child(3n) { background: #0b2f66; }
.qr-grid span:nth-child(7n) { background: #1655ac; }
.qr-grid span:nth-child(4n+1) { background: #0b2f66; }
.qr-grid span:nth-child(11) { background: #56b3ff; }

.download-meta { list-style: none; margin: 24px 0 0; padding: 20px 0 0; border-top: 1px solid rgba(255, 255, 255, .18); }
.download-meta li {
  display: flex;
  justify-content: space-between;
  gap: 12px;
  padding: 7px 0;
  font-size: .87rem;
}
.download-meta span { color: rgba(255, 255, 255, .68); }
.download-meta strong { color: #fff; }

/* FAQ */
.faq { margin-top: clamp(48px, 6vw, 76px); }
.faq-title { text-align: center; margin-bottom: 24px; }
.faq-list { display: grid; gap: 12px; max-width: 860px; margin: 0 auto; }
.faq-list details {
  background: #fff;
  border: 1px solid var(--ink-200);
  border-radius: var(--radius);
  box-shadow: var(--shadow-sm);
  overflow: hidden;
  transition: border-color .25s, box-shadow .25s;
}
.faq-list details[open] { border-color: rgba(31, 111, 224, .32); box-shadow: var(--shadow); }
.faq-list summary {
  list-style: none;
  cursor: pointer;
  position: relative;
  padding: 18px 54px 18px 24px;
  font-weight: 600;
  color: var(--ink-900);
  font-size: .98rem;
}
.faq-list summary::-webkit-details-marker { display: none; }
.faq-list summary::after {
  content: "";
  position: absolute;
  right: 24px; top: 50%;
  width: 9px; height: 9px;
  border-right: 2px solid var(--blue-600);
  border-bottom: 2px solid var(--blue-600);
  transform: translateY(-70%) rotate(45deg);
  transition: transform .3s var(--ease);
}
.faq-list details[open] summary::after { transform: translateY(-30%) rotate(-135deg); }
.faq-list p { margin: 0; padding: 0 24px 20px; color: var(--ink-500); font-size: .92rem; }

/* ---------------- 底部行动区 ---------------- */
.cta-band {
  padding: clamp(46px, 6vw, 72px) 0;
  background:
    radial-gradient(760px 380px at 82% 0%, rgba(86, 179, 255, .4), transparent 66%),
    linear-gradient(120deg, #071a38, #1655ac 78%);
  color: #fff;
}
.cta-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 28px;
  flex-wrap: wrap;
}
.cta-inner h2 { color: #fff; margin-bottom: .25em; }
.cta-inner p { margin: 0; color: rgba(255, 255, 255, .8); }

/* ---------------- 页脚 ---------------- */
.site-footer { background: #061428; color: rgba(255, 255, 255, .7); padding-top: 60px; }
.footer-inner {
  display: flex;
  justify-content: space-between;
  gap: 40px;
  flex-wrap: wrap;
  padding-bottom: 44px;
}
.footer-brand { max-width: 320px; }
.footer-brand p { margin: 16px 0 0; font-size: .9rem; }
.footer-links { display: flex; gap: clamp(36px, 6vw, 88px); }
.footer-links h4 { color: #fff; font-size: .95rem; margin-bottom: .9em; }
.footer-links ul { list-style: none; margin: 0; padding: 0; }
.footer-links li { margin-bottom: 10px; }
.footer-links a { font-size: .9rem; transition: color .2s; }
.footer-links a:hover { color: var(--sky-300); }
.footer-bottom {
  display: flex;
  justify-content: space-between;
  gap: 14px;
  flex-wrap: wrap;
  padding-top: 22px;
  padding-bottom: 26px;
  border-top: 1px solid rgba(255, 255, 255, .1);
  font-size: .82rem;
}
.footer-bottom p { margin: 0; }

/* ---------------- 返回顶部 ---------------- */
.back-top {
  position: fixed;
  right: 24px; bottom: 26px;
  width: 46px; height: 46px;
  display: grid; place-items: center;
  border: 0;
  border-radius: 50%;
  color: #fff;
  background: linear-gradient(135deg, var(--blue-600), var(--sky-400));
  box-shadow: 0 12px 26px rgba(31, 111, 224, .4);
  cursor: pointer;
  opacity: 0;
  visibility: hidden;
  transform: translateY(14px);
  transition: opacity .3s, transform .3s var(--ease), visibility .3s;
  z-index: 90;
}
.back-top.show { opacity: 1; visibility: visible; transform: translateY(0); }
.back-top svg { width: 22px; height: 22px; }

/* ---------------- 滚动动效 ---------------- */
.reveal { opacity: 0; transform: translateY(26px); transition: opacity .7s var(--ease), transform .7s var(--ease); }
.reveal.visible { opacity: 1; transform: none; }

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

/* 平板 / 小笔记本 */
@media (max-width: 1024px) {
  .hero { padding-top: calc(var(--header-h) + 46px); }
  .hero-inner { grid-template-columns: 1fr; gap: 48px; text-align: center; }
  .hero-desc { margin-left: auto; margin-right: auto; }
  .hero-actions { justify-content: center; }
  .hero-meta { margin-left: auto; margin-right: auto; }
  .hero-visual { order: 2; }
  .float-card-a { left: 0; }
  .float-card-b { right: 0; }

  .showcase-grid { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .showcase-card:last-child { grid-column: 1 / -1; max-width: 520px; margin: 0 auto; width: 100%; }

  .intro-grid { grid-template-columns: 1fr; }
  .download-layout { grid-template-columns: 1fr; }
  .download-card { max-width: 460px; margin: 0 auto; width: 100%; }
}

/* 导航折叠 */
@media (max-width: 880px) {
  .nav-toggle { display: block; }
  .main-nav {
    position: fixed;
    top: var(--header-h);
    left: 0; right: 0;
    flex-direction: column;
    align-items: stretch;
    gap: 10px;
    padding: 18px 24px 26px;
    background: rgba(7, 24, 50, .96);
    backdrop-filter: blur(16px);
    border-top: 1px solid rgba(255, 255, 255, .1);
    box-shadow: 0 24px 40px rgba(2, 12, 30, .5);
    transform: translateY(-12px);
    opacity: 0;
    visibility: hidden;
    transition: opacity .3s var(--ease), transform .3s var(--ease), visibility .3s;
    max-height: calc(100vh - var(--header-h));
    overflow-y: auto;
  }
  .main-nav.open { opacity: 1; visibility: visible; transform: translateY(0); }
  .main-nav ul { flex-direction: column; align-items: stretch; gap: 4px; }
  .nav-link { display: block; padding: 13px 14px; font-size: .98rem; border-radius: 12px; }
  .nav-link.active::after { display: none; }
  .nav-link.active { background: rgba(86, 179, 255, .18); color: #fff; }
  .btn-nav { margin-top: 8px; width: 100%; padding: 14px 20px; }
}

/* 手机 */
@media (max-width: 640px) {
  body { font-size: 15.5px; }
  .container { padding: 0 18px; }
  .hero { padding-bottom: 60px; }
  .hero-meta { grid-template-columns: repeat(3, 1fr); gap: 10px; padding-top: 18px; }
  .hero-meta strong { font-size: 1.15rem; }
  .phone-frame { width: min(280px, 86%); border-radius: 32px; padding: 10px; }
  .phone-frame img { border-radius: 24px; }
  .float-card { font-size: .74rem; padding: 8px 12px; }
  .float-card-a { top: 8%; }
  .float-card-b { bottom: 8%; }

  .showcase-grid { grid-template-columns: 1fr; }
  .showcase-card:last-child { max-width: none; }
  .showcase-media { padding: 20px 20px 0; }
  .showcase-body { padding: 20px 20px 24px; }

  .intro-cards { grid-template-columns: 1fr; }
  .intro-copy .btn { width: 100%; }

  .hero-actions .btn { flex: 1 1 100%; }
  .steps .hero-actions .btn { flex: 1 1 auto; }

  .review-card, .feature-card { padding: 24px 22px; }

  .cta-inner { flex-direction: column; align-items: flex-start; text-align: left; }
  .cta-inner .btn { width: 100%; }

  .footer-inner { flex-direction: column; gap: 28px; }
  .footer-links { gap: 40px; }
  .footer-bottom { flex-direction: column; }

  .back-top { right: 16px; bottom: 18px; width: 42px; height: 42px; }
}

@media (max-width: 400px) {
  .logo-text { font-size: .98rem; }
  .float-card { display: none; }
  .hero-meta { grid-template-columns: 1fr 1fr; }
}

/* 大屏优化 */
@media (min-width: 1440px) {
  .container { max-width: 1280px; }
}

/* 无障碍与动效偏好 */
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  .reveal { opacity: 1; transform: none; transition: none; }
  .phone-frame, .float-card { animation: none; }
}