/* ==========================================================
   店小秘 官方下载站 — 全局样式
   纯静态 / 无框架 / 移动端优先
   ========================================================== */

:root {
  --emerald-50: #ecfdf5;
  --emerald-100: #d1fae5;
  --emerald-200: #a7f3d0;
  --emerald-400: #34d399;
  --emerald-500: #10b981;
  --emerald-600: #059669;
  --emerald-700: #047857;
  --teal-50: #f0fdfa;
  --teal-200: #99f6e4;
  --gray-50: #f9fafb;
  --gray-100: #f3f4f6;
  --gray-200: #e5e7eb;
  --gray-400: #9ca3af;
  --gray-500: #6b7280;
  --gray-600: #4b5563;
  --gray-700: #374151;
  --gray-800: #1f2937;
  --gray-900: #111827;
  --white: #ffffff;
  --radius-lg: .5rem;
  --radius-xl: .75rem;
  --radius-2xl: 1rem;
  --radius-3xl: 1.5rem;
  --shadow-sm: 0 1px 2px rgba(17, 24, 39, .06);
  --shadow-md: 0 4px 6px -1px rgba(17, 24, 39, .08), 0 2px 4px -2px rgba(17, 24, 39, .06);
  --shadow-xl: 0 20px 25px -5px rgba(17, 24, 39, .1), 0 8px 10px -6px rgba(17, 24, 39, .06);
  --font-sans: ui-sans-serif, system-ui, -apple-system, "Segoe UI", Roboto, "Helvetica Neue",
    "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "Noto Sans SC", sans-serif;
  --header-h: 68px;
}

*,
*::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-weight: 400;
  font-size: 16px;
  line-height: 1.75;
  color: var(--gray-700);
  background: var(--white);
  -webkit-font-smoothing: antialiased;
}

img { max-width: 100%; height: auto; display: block; }
a { color: var(--emerald-600); text-decoration: none; transition: color .2s ease; }
a:hover { color: var(--emerald-700); }
h1, h2, h3, h4 { color: var(--gray-900); font-weight: 700; line-height: 1.25; margin: 0; }
p { margin: 0; }
ul, ol { margin: 0; padding: 0; list-style: none; }
button { font: inherit; color: inherit; }
svg { display: block; }

.container {
  width: 100%;
  max-width: 72rem; /* max-w-6xl */
  margin: 0 auto;
  padding-left: 16px;
  padding-right: 16px;
}
.container-narrow { max-width: 48rem; }

.sr-only {
  position: absolute; width: 1px; height: 1px; padding: 0; margin: -1px;
  overflow: hidden; clip: rect(0 0 0 0); white-space: nowrap; border: 0;
}

.skip-link {
  position: absolute; left: 16px; top: -60px; z-index: 100;
  background: var(--emerald-600); color: #fff; padding: 10px 16px;
  border-radius: var(--radius-lg); transition: top .2s ease;
}
.skip-link:focus { top: 12px; color: #fff; }

/* ===================== Header ===================== */
.site-header {
  position: fixed;
  top: 0; left: 0; right: 0;
  z-index: 50;
  background: rgba(255, 255, 255, .92);
  backdrop-filter: saturate(180%) blur(12px);
  border-bottom: 1px solid transparent;
  transition: border-color .2s ease, box-shadow .2s ease;
}
.site-header.is-scrolled {
  border-bottom-color: var(--gray-100);
  box-shadow: var(--shadow-sm);
}
.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  height: var(--header-h);
}
.brand {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  color: var(--gray-900);
  font-weight: 700;
  font-size: 1.125rem;
  letter-spacing: .01em;
}
.brand:hover { color: var(--gray-900); }
.brand-logo {
  width: 36px; height: 36px;
  object-fit: contain;
  border-radius: 8px;
  background: var(--emerald-50);
  padding: 2px;
}
.brand-sub {
  font-size: .75rem;
  font-weight: 500;
  color: var(--emerald-600);
  background: var(--emerald-50);
  border-radius: 9999px;
  padding: 2px 8px;
}
.nav { display: none; }
.nav-list { display: flex; align-items: center; gap: 4px; }
.nav-link {
  display: inline-block;
  padding: 8px 14px;
  border-radius: var(--radius-lg);
  font-size: .9375rem;
  color: var(--gray-600);
}
.nav-link:hover { color: var(--gray-900); background: var(--gray-50); }
.nav-link[aria-current="page"] {
  color: var(--emerald-600);
  background: var(--emerald-50);
  font-weight: 600;
}
.header-cta { display: none; }

/* Buttons */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 10px;
  font-weight: 600;
  line-height: 1.2;
  border: 1px solid transparent;
  cursor: pointer;
  transition: transform .2s ease, box-shadow .2s ease, background-color .2s ease, border-color .2s ease, color .2s ease;
}
.btn svg { flex: 0 0 auto; }
.btn-primary {
  background: var(--emerald-600);
  color: #fff;
  border-radius: var(--radius-2xl);
  padding: 16px 32px;
  font-size: 1.0625rem;
  box-shadow: 0 10px 24px -8px rgba(5, 150, 105, .55);
}
.btn-primary:hover { background: var(--emerald-700); color: #fff; transform: translateY(-2px); }
.btn-primary:focus-visible { outline: 3px solid var(--emerald-200); outline-offset: 2px; }
.btn-nav {
  background: var(--emerald-600);
  color: #fff;
  border-radius: var(--radius-xl);
  padding: 10px 18px;
  font-size: .9375rem;
}
.btn-nav:hover { background: var(--emerald-700); color: #fff; }
.btn-ghost {
  background: #fff;
  color: var(--gray-700);
  border-color: var(--gray-200);
  border-radius: var(--radius-2xl);
  padding: 16px 28px;
  font-size: 1rem;
}
.btn-ghost:hover { border-color: var(--emerald-200); color: var(--emerald-700); background: var(--emerald-50); }
.btn-block { width: 100%; }
.btn-sm { padding: 10px 18px; font-size: .9375rem; border-radius: var(--radius-xl); }

/* Hamburger */
.hamburger {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 44px; height: 44px;
  border: 1px solid var(--gray-200);
  background: #fff;
  border-radius: var(--radius-lg);
  cursor: pointer;
}
.hamburger:hover { background: var(--gray-50); }
.hamburger:focus-visible { outline: 3px solid var(--emerald-200); outline-offset: 2px; }
.hamburger-icon { position: relative; width: 20px; height: 14px; }
.hamburger-icon span {
  position: absolute; left: 0; width: 20px; height: 2px;
  background: var(--gray-700); border-radius: 2px;
  transition: transform .25s ease, opacity .2s ease, top .25s ease;
}
.hamburger-icon span:nth-child(1) { top: 0; }
.hamburger-icon span:nth-child(2) { top: 6px; }
.hamburger-icon span:nth-child(3) { top: 12px; }
.hamburger[aria-expanded="true"] .hamburger-icon span:nth-child(1) { top: 6px; transform: rotate(45deg); }
.hamburger[aria-expanded="true"] .hamburger-icon span:nth-child(2) { opacity: 0; }
.hamburger[aria-expanded="true"] .hamburger-icon span:nth-child(3) { top: 6px; transform: rotate(-45deg); }

.mobile-menu {
  position: fixed;
  inset: var(--header-h) 0 auto 0;
  z-index: 45;
  background: #fff;
  border-bottom: 1px solid var(--gray-100);
  box-shadow: var(--shadow-xl);
  padding: 12px 16px 24px;
  max-height: calc(100vh - var(--header-h));
  overflow-y: auto;
  transform: translateY(-8px);
  opacity: 0;
  visibility: hidden;
  transition: opacity .2s ease, transform .2s ease, visibility .2s ease;
}
.mobile-menu.is-open { opacity: 1; transform: translateY(0); visibility: visible; }
.mobile-menu ul { display: grid; gap: 4px; }
.mobile-menu .nav-link { display: block; padding: 12px 14px; font-size: 1rem; }
.mobile-menu .btn { margin-top: 12px; }
body.menu-open { overflow: hidden; }

/* ===================== Hero ===================== */
.hero {
  position: relative;
  overflow: hidden;
  padding: calc(var(--header-h) + 40px) 0 64px;
  background: linear-gradient(165deg, var(--emerald-50) 0%, #ffffff 45%, var(--teal-50) 100%);
}
.hero-blob {
  position: absolute;
  border-radius: 50%;
  filter: blur(64px);
  opacity: .3;
  pointer-events: none;
}
.hero-blob-1 {
  width: 380px; height: 380px;
  top: -120px; right: -100px;
  background: radial-gradient(circle, var(--emerald-400), transparent 65%);
}
.hero-blob-2 {
  width: 340px; height: 340px;
  bottom: -140px; left: -120px;
  background: radial-gradient(circle, var(--teal-200), transparent 65%);
}
.hero-grid { position: relative; display: grid; gap: 40px; align-items: center; }
.hero-copy { text-align: center; }
.trust-badge {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  background: var(--emerald-100);
  color: var(--emerald-700);
  border-radius: 9999px;
  padding: 6px 14px;
  font-size: .875rem;
  font-weight: 600;
}
.hero h1 {
  margin-top: 20px;
  font-size: 2.75rem;
  line-height: 1.15;
  letter-spacing: -.02em;
}
.text-gradient {
  background: linear-gradient(100deg, var(--emerald-500), #0d9488 55%, #0891b2);
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
}
.hero-sub {
  margin: 20px auto 0;
  max-width: 34rem;
  font-size: 1.125rem;
  color: var(--gray-600);
}
.hero-actions {
  margin-top: 28px;
  display: flex;
  flex-direction: column;
  align-items: stretch;
  gap: 12px;
}
.animate-glow { animation: glow 2.8s ease-in-out infinite; }
@keyframes glow {
  0%, 100% { box-shadow: 0 10px 24px -8px rgba(5, 150, 105, .45); }
  50% { box-shadow: 0 14px 36px -6px rgba(16, 185, 129, .7); }
}
.hero-note {
  margin-top: 16px;
  font-size: .8125rem;
  color: var(--gray-500);
}
.hero-visual { position: relative; }
.hero-visual img {
  width: 100%;
  max-width: 600px;
  height: auto;
  margin: 0 auto;
  filter: drop-shadow(0 24px 40px rgba(17, 24, 39, .12));
}
.hero-os {
  margin-top: 18px;
  font-size: .875rem;
  color: var(--gray-500);
  text-align: center;
}

/* ===================== 数据信任条 ===================== */
.proof {
  background: var(--gray-900);
  color: #fff;
  padding: 36px 0;
}
.proof-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 16px;
  text-align: center;
}
.proof-item svg { margin: 0 auto 8px; width: 32px; height: 32px; color: var(--emerald-400); }
.proof-num { font-size: 1.75rem; font-weight: 700; color: #fff; line-height: 1.2; }
.proof-label { font-size: .8125rem; color: var(--gray-400); }

/* ===================== Sections ===================== */
.section { padding: 64px 0; }
.section-alt { background: var(--gray-50); }
.section-head { text-align: center; max-width: 44rem; margin: 0 auto 40px; }
.section-head h2 { font-size: 2rem; letter-spacing: -.01em; }
.section-head p { margin-top: 12px; font-size: 1.0625rem; color: var(--gray-600); }
.eyebrow {
  display: inline-block;
  font-size: .8125rem;
  font-weight: 700;
  letter-spacing: .08em;
  text-transform: uppercase;
  color: var(--emerald-600);
  margin-bottom: 10px;
}

/* 核心功能卡片 */
.feature-grid { display: grid; gap: 20px; }
.feature-card {
  display: flex;
  flex-direction: column;
  gap: 14px;
  padding: 28px;
  background: #fff;
  border: 1px solid var(--gray-100);
  border-radius: var(--radius-3xl);
  box-shadow: var(--shadow-sm);
  transition: border-color .25s ease, box-shadow .25s ease, transform .25s ease;
}
.feature-card:hover {
  border-color: var(--emerald-200);
  box-shadow: var(--shadow-xl);
  transform: translateY(-3px);
}
.feature-icon {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 60px; height: 60px;
  border-radius: var(--radius-2xl);
  color: #fff;
  transition: transform .25s ease;
}
.feature-card:hover .feature-icon { transform: scale(1.08); }
.grad-purple { background: linear-gradient(135deg, #a855f7, #ec4899); }
.grad-cyan { background: linear-gradient(135deg, #06b6d4, #3b82f6); }
.grad-amber { background: linear-gradient(135deg, #f59e0b, #f97316); }
.grad-emerald { background: linear-gradient(135deg, #10b981, #14b8a6); }
.feature-card h3 { font-size: 1.3125rem; }
.feature-card p { color: var(--gray-600); font-size: 1rem; }

/* 平台覆盖 */
.platform-grid { display: grid; grid-template-columns: repeat(2, 1fr); gap: 16px; }
.platform-card {
  display: block;
  text-align: center;
  padding: 24px 12px;
  background: #fff;
  border: 1px solid var(--gray-100);
  border-radius: var(--radius-3xl);
  box-shadow: var(--shadow-sm);
  color: var(--gray-900);
  transition: border-color .25s ease, box-shadow .25s ease, transform .25s ease;
}
.platform-card:hover {
  color: var(--gray-900);
  border-color: var(--emerald-200);
  box-shadow: var(--shadow-xl);
  transform: translateY(-3px);
}
.platform-card svg { margin: 0 auto 12px; width: 40px; height: 40px; color: var(--gray-700); transition: color .2s ease; }
.platform-card:hover svg { color: var(--emerald-600); }
.platform-card h3 { font-size: 1.125rem; }
.platform-ver { display: block; margin-top: 4px; font-size: .8125rem; color: var(--gray-500); }
.platform-more {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 6px;
  margin-top: 10px;
  font-size: .8125rem;
  font-weight: 600;
  color: var(--emerald-600);
  opacity: 0;
  transition: opacity .2s ease;
}
.platform-card:hover .platform-more,
.platform-card:focus-visible .platform-more { opacity: 1; }

/* 学习中心 */
.learn-head {
  display: flex;
  align-items: flex-end;
  justify-content: space-between;
  gap: 16px;
  margin-bottom: 32px;
}
.learn-head h2 { font-size: 2rem; }
.learn-head p { margin-top: 10px; color: var(--gray-600); }
.link-all {
  display: none;
  align-items: center;
  gap: 6px;
  font-weight: 600;
  font-size: .9375rem;
  white-space: nowrap;
}
.article-grid { display: grid; gap: 20px; }
.article-group { margin-top: 52px; }
.article-group:first-of-type { margin-top: 0; }
.article-group-title {
  margin: 0 0 20px;
  padding-left: 12px;
  font-size: 1.375rem;
  line-height: 1.3;
  border-left: 4px solid var(--emerald-500);
}
.article-card {
  display: flex;
  flex-direction: column;
  height: 100%;
  background: #fff;
  border: 1px solid var(--gray-100);
  border-radius: var(--radius-2xl);
  overflow: hidden;
  color: var(--gray-900);
  box-shadow: var(--shadow-sm);
  transition: border-color .25s ease, box-shadow .25s ease, transform .25s ease;
}
.article-card:hover {
  color: var(--gray-900);
  border-color: var(--emerald-200);
  box-shadow: var(--shadow-xl);
  transform: translateY(-3px);
}
.article-cover { position: relative; height: 176px; overflow: hidden; background: var(--gray-100); }
.article-cover img { width: 100%; height: 100%; object-fit: cover; transition: transform .45s ease; }
.article-card:hover .article-cover img { transform: scale(1.05); }
.article-tag {
  position: absolute;
  top: 12px; left: 12px;
  background: var(--emerald-500);
  color: #fff;
  font-size: .75rem;
  font-weight: 600;
  padding: 3px 10px;
  border-radius: var(--radius-lg);
}
.article-body { display: flex; flex-direction: column; flex: 1; padding: 20px 20px 16px; }
.article-body h3 {
  font-size: 1.0625rem;
  line-height: 1.5;
  display: -webkit-box;
  -webkit-line-clamp: 2;
  -webkit-box-orient: vertical;
  overflow: hidden;
  transition: color .2s ease;
}
.article-card:hover .article-body h3 { color: var(--emerald-600); }
.article-excerpt {
  margin-top: 8px;
  font-size: .875rem;
  color: var(--gray-500);
  display: -webkit-box;
  -webkit-line-clamp: 2;
  -webkit-box-orient: vertical;
  overflow: hidden;
}
.article-meta {
  margin-top: 16px;
  padding-top: 12px;
  border-top: 1px solid var(--gray-50);
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 8px;
  font-size: .75rem;
  color: var(--gray-400);
}
.article-meta span { display: inline-flex; align-items: center; gap: 4px; }
.article-meta svg { width: 14px; height: 14px; }

/* FAQ */
.faq-list { display: grid; gap: 12px; }
.faq-item {
  background: #fff;
  border: 1px solid var(--gray-100);
  border-radius: var(--radius-2xl);
  overflow: hidden;
}
.faq-q {
  margin: 0;
  font-size: 1rem;
}
.faq-trigger {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  width: 100%;
  padding: 18px 20px;
  background: none;
  border: 0;
  text-align: left;
  font-weight: 600;
  color: var(--gray-900);
  cursor: pointer;
}
.faq-trigger:hover { background: var(--gray-50); }
.faq-trigger:focus-visible { outline: 3px solid var(--emerald-200); outline-offset: -3px; }
.faq-trigger svg { flex: 0 0 auto; width: 18px; height: 18px; color: var(--emerald-600); transition: transform .25s ease; }
.faq-trigger[aria-expanded="true"] svg { transform: rotate(45deg); }
.faq-answer {
  padding: 0 20px 18px;
  color: var(--gray-600);
  font-size: .9375rem;
}
.faq-answer[hidden] { display: none; }
.faq-answer a { text-decoration: underline; }

/* CTA 区块 */
.cta-band {
  background: linear-gradient(120deg, var(--emerald-600), #0d9488 60%, #0f766e);
  color: #fff;
  padding: 56px 0;
  text-align: center;
}
.cta-band h2 { color: #fff; font-size: 1.875rem; }
.cta-band p { margin: 12px auto 24px; max-width: 38rem; color: rgba(255, 255, 255, .85); }
.cta-band .btn-primary { background: #fff; color: var(--emerald-700); box-shadow: 0 12px 28px -10px rgba(0, 0, 0, .35); }
.cta-band .btn-primary:hover { background: var(--emerald-50); color: var(--emerald-700); }

/* ===================== Footer ===================== */
.site-footer { background: var(--gray-900); color: var(--gray-400); padding: 56px 0 24px; }
.footer-grid { display: grid; grid-template-columns: repeat(2, 1fr); gap: 32px 24px; }
.footer-brand .brand { color: #fff; margin-bottom: 12px; }
.footer-brand p { font-size: .875rem; line-height: 1.7; color: var(--gray-400); max-width: 20rem; }
.footer-col h3 {
  color: #fff;
  font-size: .9375rem;
  font-weight: 600;
  margin-bottom: 12px;
}
.footer-col ul { display: grid; gap: 8px; }
.footer-col a { color: var(--gray-400); font-size: .875rem; }
.footer-col a:hover { color: var(--emerald-400); }
.footer-bottom {
  margin-top: 40px;
  padding-top: 20px;
  border-top: 1px solid rgba(255, 255, 255, .08);
  display: flex;
  flex-direction: column;
  gap: 8px;
  font-size: .8125rem;
  color: var(--gray-500);
}
.footer-bottom a { color: var(--gray-500); }
.footer-bottom a:hover { color: var(--gray-400); }

/* ===================== 子页面 ===================== */
.page-hero {
  padding: calc(var(--header-h) + 40px) 0 40px;
  background: linear-gradient(165deg, var(--emerald-50), #fff 70%);
  border-bottom: 1px solid var(--gray-100);
}
.breadcrumb { font-size: .8125rem; color: var(--gray-500); margin-bottom: 12px; }
.breadcrumb a { color: var(--gray-500); }
.breadcrumb a:hover { color: var(--emerald-600); }
.breadcrumb span { margin: 0 6px; color: var(--gray-400); }
.page-hero h1 { font-size: 2.25rem; letter-spacing: -.01em; }
.page-hero .lead { margin-top: 14px; max-width: 44rem; color: var(--gray-600); font-size: 1.0625rem; }
.page-body { padding: 56px 0; }
.prose { max-width: 48rem; }
.prose h2 { font-size: 1.5rem; margin: 36px 0 12px; }
.prose h3 { font-size: 1.1875rem; margin: 28px 0 10px; }
.prose p { margin: 12px 0; color: var(--gray-600); }
.prose ul { list-style: disc; padding-left: 1.25rem; margin: 12px 0; color: var(--gray-600); }
.prose li { margin: 6px 0; }
.prose strong { color: var(--gray-900); }

/* 下载页 */
.dl-layout { display: grid; gap: 32px; }
.dl-main { display: grid; gap: 24px; }
.plat-block {
  background: #fff;
  border: 1px solid var(--gray-100);
  border-radius: var(--radius-3xl);
  padding: 24px;
  box-shadow: var(--shadow-sm);
}
.plat-block header { display: flex; align-items: center; gap: 14px; margin-bottom: 8px; }
.plat-block header svg { width: 32px; height: 32px; color: var(--gray-700); }
.plat-block h2 { font-size: 1.25rem; }
.plat-block .meta { font-size: .8125rem; color: var(--gray-500); }
.plat-block p { color: var(--gray-600); font-size: .9375rem; margin: 10px 0 16px; }
.dl-side {
  background: var(--gray-50);
  border: 1px solid var(--gray-100);
  border-radius: var(--radius-3xl);
  padding: 24px;
}
.dl-side h2 { font-size: 1.125rem; margin-bottom: 12px; }
.dl-side ul { display: grid; gap: 10px; font-size: .875rem; color: var(--gray-600); }
.dl-side li { display: flex; gap: 8px; }
.dl-side svg { width: 18px; height: 18px; color: var(--emerald-600); flex: 0 0 auto; margin-top: 3px; }
.dl-side .btn { margin-top: 18px; }

/* 文章页 */
.article-page { max-width: 48rem; }
.article-page .article-lead { font-size: 1.0625rem; color: var(--gray-600); margin-top: 16px; }
.article-page .article-meta { margin-top: 20px; border-top: 0; padding-top: 0; font-size: .8125rem; justify-content: flex-start; gap: 18px; }
.article-page .hero-img { margin: 28px 0; border-radius: var(--radius-2xl); overflow: hidden; border: 1px solid var(--gray-100); }
.related { margin-top: 48px; padding-top: 28px; border-top: 1px solid var(--gray-100); }
.related h2 { font-size: 1.25rem; margin-bottom: 16px; }
.related ul { display: grid; gap: 10px; }
.related a { font-size: .9375rem; }

/* FAQ 页 */
.faq-page .faq-list { max-width: 48rem; }

/* 关于页 */
.about-grid { display: grid; gap: 24px; }
.about-card {
  background: #fff;
  border: 1px solid var(--gray-100);
  border-radius: var(--radius-3xl);
  padding: 24px;
  box-shadow: var(--shadow-sm);
}
.about-card h2 { font-size: 1.1875rem; margin-bottom: 8px; }
.about-card p { color: var(--gray-600); font-size: .9375rem; }
.about-stats { display: grid; grid-template-columns: repeat(2, 1fr); gap: 16px; margin: 24px 0; }
.about-stat { background: var(--emerald-50); border-radius: var(--radius-2xl); padding: 18px; text-align: center; }
.about-stat strong { display: block; font-size: 1.5rem; color: var(--emerald-700); }
.about-stat span { font-size: .8125rem; color: var(--gray-600); }

/* 404 */
.notfound { text-align: center; padding: calc(var(--header-h) + 80px) 0 80px; }
.notfound h1 { font-size: 3rem; }
.notfound p { margin: 12px 0 24px; color: var(--gray-600); }

/* 滚动淡入 */
.reveal { opacity: 0; transform: translateY(16px); transition: opacity .6s ease, transform .6s ease; }
.reveal.is-visible { opacity: 1; transform: none; }

/* ===================== 断点 ===================== */
@media (min-width: 480px) {
  .hero-actions { flex-direction: row; justify-content: center; align-items: center; }
  .footer-bottom { flex-direction: row; justify-content: space-between; align-items: center; }
}

@media (min-width: 768px) {
  :root { --header-h: 72px; }
  .hamburger { display: none; }
  .mobile-menu { display: none; }
  .nav { display: block; }
  .header-cta { display: inline-flex; }
  .hero { padding: calc(var(--header-h) + 56px) 0 80px; }
  .hero h1 { font-size: 3.5rem; }
  .hero-copy { text-align: left; }
  .hero-actions { justify-content: flex-start; }
  .hero-sub { margin-left: 0; }
  .section { padding: 96px 0; }
  .feature-grid { grid-template-columns: repeat(2, 1fr); gap: 24px; }
  .platform-grid { grid-template-columns: repeat(4, 1fr); }
  .article-grid { grid-template-columns: repeat(2, 1fr); gap: 24px; }
  .learn-head h2, .section-head h2 { font-size: 2.25rem; }
  .link-all { display: inline-flex; }
  .footer-grid { grid-template-columns: repeat(4, 1fr); }
  .page-hero h1 { font-size: 2.75rem; }
  .about-grid { grid-template-columns: repeat(2, 1fr); }
  .about-stats { grid-template-columns: repeat(4, 1fr); }
  .proof { padding: 44px 0; }
  .proof-num { font-size: 2.25rem; }
  .proof-label { font-size: .875rem; }
}

@media (min-width: 1024px) {
  .hero { padding: calc(var(--header-h) + 64px) 0 96px; }
  .hero h1 { font-size: 4.5rem; }
  .hero-grid { grid-template-columns: minmax(0, 1.05fr) minmax(0, .95fr); gap: 56px; }
  .hero-visual img { max-width: 100%; }
  .feature-card { padding: 32px; }
  .article-grid { grid-template-columns: repeat(3, 1fr); }
  .article-grid.is-wide { grid-template-columns: repeat(4, 1fr); }
  .dl-layout { grid-template-columns: minmax(0, 1.6fr) minmax(0, 1fr); align-items: start; }
  .dl-side { position: sticky; top: calc(var(--header-h) + 24px); }
  .page-body { padding: 72px 0; }
  .about-grid { grid-template-columns: repeat(3, 1fr); }
}

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  *, *::before, *::after { animation: none !important; transition: none !important; }
  .reveal { opacity: 1; transform: none; }
}