/* ===== ROOT VARIABLES ===== */
:root {
  --blue-deep: #1a73e8;
  --blue-light: #4a90d9;
  --blue-pale: #e8f0fe;
  --green-safe: #34a853;
  --red-accent: #ea4335;
  --yellow-star: #fbbc04;
  --text-main: #202124;
  --text-gray: #5f6368;
  --text-light: #9aa0a6;
  --border: #dadce0;
  --bg-white: #ffffff;
  --bg-light: #f8f9fa;
  --bg-section: #f1f3f4;
  --shadow-sm: 0 1px 3px rgba(0,0,0,.12), 0 1px 2px rgba(0,0,0,.08);
  --shadow-md: 0 4px 12px rgba(0,0,0,.12), 0 2px 6px rgba(0,0,0,.08);
  --shadow-lg: 0 8px 24px rgba(0,0,0,.14);
  --radius: 8px;
  --radius-lg: 16px;
  --font-main: 'Noto Sans SC', 'PingFang SC', 'Microsoft YaHei', sans-serif;
  --font-en: 'Google Sans', 'Product Sans', 'Segoe UI', sans-serif;
  --transition: 0.22s cubic-bezier(.4,0,.2,1);
}

/* ===== RESET ===== */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
html { scroll-behavior: smooth; font-size: 16px; }
body {
  font-family: var(--font-main);
  color: var(--text-main);
  background: var(--bg-white);
  line-height: 1.65;
  -webkit-font-smoothing: antialiased;
}
a { color: var(--blue-deep); text-decoration: none; transition: color var(--transition); }
a:hover { color: var(--blue-light); }
img { max-width: 100%; display: block; }
ul { list-style: none; }

/* ===== TOPBAR ===== */
.topbar {
  width: 100%;
  background: var(--bg-white);
  border-bottom: 1px solid var(--border);
  position: sticky;
  top: 0;
  z-index: 999;
  box-shadow: 0 1px 4px rgba(0,0,0,.07);
}
.topbar-inner {
  max-width: 1200px;
  margin: 0 auto;
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0 24px;
  height: 64px;
  gap: 16px;
}
.logo-wrap {
  display: flex;
  align-items: center;
  gap: 10px;
  flex-shrink: 0;
}
.logo-wrap img { width: 150px; height: 42px; }
.logo-wrap .brand-name {
  font-size: 1.15rem;
  font-weight: 700;
  color: var(--text-main);
  letter-spacing: -.3px;
  font-family: var(--font-en);
}
.brand-name span { color: var(--blue-deep); }

/* ===== NAV ===== */
.main-nav { display: flex; align-items: center; gap: 4px; }
.main-nav a {
  display: flex;
  align-items: center;
  gap: 6px;
  padding: 8px 14px;
  border-radius: 24px;
  font-size: .92rem;
  color: var(--text-gray);
  font-weight: 500;
  transition: background var(--transition), color var(--transition);
  white-space: nowrap;
}
.main-nav a:hover, .main-nav a.active {
  background: var(--blue-pale);
  color: var(--blue-deep);
}
.main-nav a i { font-size: 1rem; }

/* ===== HAMBURGER ===== */
.hamburger {
  display: none;
  background: none;
  border: none;
  cursor: pointer;
  padding: 8px;
  border-radius: 50%;
  transition: background var(--transition);
}
.hamburger:hover { background: var(--bg-section); }
.hamburger span {
  display: block;
  width: 22px;
  height: 2px;
  background: var(--text-gray);
  margin: 5px 0;
  border-radius: 2px;
  transition: transform var(--transition), opacity var(--transition);
}
.mobile-nav {
  display: none;
  flex-direction: column;
  background: var(--bg-white);
  border-top: 1px solid var(--border);
  padding: 12px 0;
}
.mobile-nav a {
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 12px 24px;
  color: var(--text-gray);
  font-weight: 500;
  font-size: .95rem;
}
.mobile-nav a:hover { background: var(--bg-light); color: var(--blue-deep); }
.mobile-nav.open { display: flex; }

/* ===== FOOTER ===== */
.site-footer {
  background: var(--bg-section);
  border-top: 1px solid var(--border);
  padding: 48px 24px 28px;
}
.footer-inner {
  max-width: 1200px;
  margin: 0 auto;
}
.footer-top {
  display: grid;
  grid-template-columns: 2fr 1fr 1fr 1fr;
  gap: 40px;
  padding-bottom: 36px;
  border-bottom: 1px solid var(--border);
}
.footer-brand .logo-wrap { margin-bottom: 12px; }
.footer-brand p {
  font-size: .88rem;
  color: var(--text-gray);
  line-height: 1.7;
  max-width: 260px;
}
.footer-col h4 {
  font-size: .88rem;
  font-weight: 700;
  color: var(--text-main);
  margin-bottom: 14px;
  letter-spacing: .3px;
  text-transform: uppercase;
}
.footer-col ul li { margin-bottom: 8px; }
.footer-col ul li a {
  font-size: .875rem;
  color: var(--text-gray);
  transition: color var(--transition);
}
.footer-col ul li a:hover { color: var(--blue-deep); }
.footer-bottom {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding-top: 24px;
  flex-wrap: wrap;
  gap: 12px;
}
.footer-bottom p { font-size: .82rem; color: var(--text-light); }
.footer-links { display: flex; gap: 20px; }
.footer-links a { font-size: .82rem; color: var(--text-light); }
.footer-links a:hover { color: var(--blue-deep); }

/* ===== BUTTONS ===== */
.btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 12px 28px;
  border-radius: 24px;
  font-size: .97rem;
  font-weight: 600;
  cursor: pointer;
  border: none;
  transition: all var(--transition);
  text-align: center;
  white-space: nowrap;
  font-family: var(--font-main);
}
.btn-primary {
  background: var(--blue-deep);
  color: #fff;
  box-shadow: 0 2px 8px rgba(26,115,232,.25);
}
.btn-primary:hover {
  background: #1557b0;
  color: #fff;
  box-shadow: 0 4px 16px rgba(26,115,232,.35);
  transform: translateY(-1px);
}
.btn-outline {
  background: transparent;
  color: var(--blue-deep);
  border: 2px solid var(--blue-deep);
}
.btn-outline:hover {
  background: var(--blue-pale);
  color: var(--blue-deep);
}
.btn-white {
  background: #fff;
  color: var(--blue-deep);
  box-shadow: var(--shadow-sm);
}
.btn-white:hover {
  background: var(--blue-pale);
  color: var(--blue-deep);
  box-shadow: var(--shadow-md);
}
.btn-lg { padding: 15px 36px; font-size: 1.07rem; border-radius: 28px; }
.btn-sm { padding: 8px 18px; font-size: .85rem; border-radius: 18px; }

/* ===== SECTION TITLES ===== */
.section-title {
  font-size: 2rem;
  font-weight: 700;
  color: var(--text-main);
  line-height: 1.3;
  letter-spacing: -.4px;
}
.section-sub {
  font-size: 1.05rem;
  color: var(--text-gray);
  margin-top: 10px;
  line-height: 1.7;
}
.section-head { text-align: center; margin-bottom: 48px; }

/* ===== CARDS ===== */
.card {
  background: var(--bg-white);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: 28px;
  transition: box-shadow var(--transition), transform var(--transition);
}
.card:hover {
  box-shadow: var(--shadow-lg);
  transform: translateY(-3px);
}
.card-icon {
  width: 52px;
  height: 52px;
  border-radius: 14px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.5rem;
  margin-bottom: 16px;
}
.card-icon.blue { background: var(--blue-pale); color: var(--blue-deep); }
.card-icon.green { background: #e6f4ea; color: var(--green-safe); }
.card-icon.red { background: #fce8e6; color: var(--red-accent); }
.card-icon.yellow { background: #fef7e0; color: #f9ab00; }
.card h3 { font-size: 1.08rem; font-weight: 700; margin-bottom: 8px; }
.card p { font-size: .91rem; color: var(--text-gray); line-height: 1.65; }

/* ===== BADGE ===== */
.badge {
  display: inline-block;
  padding: 3px 10px;
  border-radius: 12px;
  font-size: .78rem;
  font-weight: 600;
  letter-spacing: .3px;
}
.badge-blue { background: var(--blue-pale); color: var(--blue-deep); }
.badge-green { background: #e6f4ea; color: var(--green-safe); }

/* ===== CONTAINER ===== */
.container { max-width: 1200px; margin: 0 auto; padding: 0 24px; }
.section { padding: 72px 0; }
.section-alt { background: var(--bg-light); }

/* ===== GRID ===== */
.grid-2 { display: grid; grid-template-columns: repeat(2,1fr); gap: 28px; }
.grid-3 { display: grid; grid-template-columns: repeat(3,1fr); gap: 28px; }
.grid-4 { display: grid; grid-template-columns: repeat(4,1fr); gap: 24px; }

/* ===== HERO ===== */
.hero {
  background: linear-gradient(135deg, #e8f0fe 0%, #f1f8ff 50%, #e6f4ea 100%);
  padding: 88px 0 72px;
  position: relative;
  overflow: hidden;
}
.hero::before {
  content: '';
  position: absolute;
  top: -80px; right: -80px;
  width: 400px; height: 400px;
  border-radius: 50%;
  background: radial-gradient(circle, rgba(26,115,232,.08) 0%, transparent 70%);
  pointer-events: none;
}
.hero-inner {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 24px;
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 60px;
  align-items: center;
}
.hero-text h1 {
  font-size: 2.7rem;
  font-weight: 800;
  line-height: 1.2;
  letter-spacing: -.6px;
  color: var(--text-main);
  margin-bottom: 20px;
}
.hero-text h1 .hl { color: var(--blue-deep); }
.hero-text p {
  font-size: 1.1rem;
  color: var(--text-gray);
  line-height: 1.75;
  margin-bottom: 32px;
}
.hero-actions { display: flex; gap: 14px; flex-wrap: wrap; }
.hero-image { position: relative; }
.hero-image img {
  width: 100%;
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-lg);
}

/* ===== STATS BAR ===== */
.stats-bar {
  background: var(--bg-white);
  border-bottom: 1px solid var(--border);
  padding: 24px 0;
}
.stats-inner {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 24px;
  display: flex;
  justify-content: space-around;
  align-items: center;
  flex-wrap: wrap;
  gap: 24px;
}
.stat-item { text-align: center; }
.stat-num {
  font-size: 1.7rem;
  font-weight: 800;
  color: var(--blue-deep);
  line-height: 1;
}
.stat-label {
  font-size: .82rem;
  color: var(--text-gray);
  margin-top: 4px;
}

/* ===== FEATURE LIST ===== */
.feature-list { display: flex; flex-direction: column; gap: 20px; }
.feature-item {
  display: flex;
  align-items: flex-start;
  gap: 16px;
}
.feature-item .fi-icon {
  width: 40px;
  height: 40px;
  border-radius: 10px;
  background: var(--blue-pale);
  color: var(--blue-deep);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.1rem;
  flex-shrink: 0;
}
.feature-item .fi-text h4 {
  font-size: .97rem;
  font-weight: 700;
  margin-bottom: 4px;
}
.feature-item .fi-text p {
  font-size: .88rem;
  color: var(--text-gray);
  line-height: 1.6;
}

/* ===== DOWNLOAD BOX ===== */
.dl-box {
  background: var(--bg-white);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: 32px;
  box-shadow: var(--shadow-md);
}
.dl-os-tab {
  display: flex;
  gap: 8px;
  margin-bottom: 24px;
  border-bottom: 1px solid var(--border);
  padding-bottom: 14px;
}
.dl-os-tab button {
  background: none;
  border: none;
  padding: 8px 18px;
  border-radius: 20px;
  font-size: .9rem;
  font-weight: 600;
  cursor: pointer;
  color: var(--text-gray);
  display: flex;
  align-items: center;
  gap: 6px;
  transition: all var(--transition);
  font-family: var(--font-main);
}
.dl-os-tab button.active, .dl-os-tab button:hover {
  background: var(--blue-pale);
  color: var(--blue-deep);
}

/* ===== BREADCRUMB ===== */
.breadcrumb {
  display: flex;
  align-items: center;
  gap: 8px;
  font-size: .85rem;
  color: var(--text-light);
  padding: 16px 0 0;
}
.breadcrumb a { color: var(--blue-deep); }
.breadcrumb span { color: var(--text-light); }

/* ===== TABLE ===== */
.compare-table { width: 100%; border-collapse: collapse; }
.compare-table th, .compare-table td {
  padding: 14px 18px;
  text-align: left;
  border-bottom: 1px solid var(--border);
  font-size: .9rem;
}
.compare-table th {
  background: var(--bg-section);
  font-weight: 700;
  color: var(--text-main);
}
.compare-table td { color: var(--text-gray); }
.compare-table tr:last-child td { border-bottom: none; }
.compare-table .check { color: var(--green-safe); font-size: 1rem; }
.compare-table .cross { color: var(--text-light); }

/* ===== FAQ ===== */
.faq-item { border-bottom: 1px solid var(--border); padding: 20px 0; }
.faq-q {
  display: flex;
  justify-content: space-between;
  align-items: center;
  cursor: pointer;
  font-weight: 600;
  font-size: .97rem;
  gap: 12px;
  user-select: none;
}
.faq-q i { color: var(--text-light); font-size: .85rem; transition: transform var(--transition); }
.faq-item.open .faq-q i { transform: rotate(180deg); }
.faq-a {
  font-size: .9rem;
  color: var(--text-gray);
  line-height: 1.7;
  margin-top: 12px;
  display: none;
}
.faq-item.open .faq-a { display: block; }

/* ===== CTA BAND ===== */
.cta-band {
  background: linear-gradient(135deg, var(--blue-deep) 0%, #1557b0 100%);
  padding: 64px 0;
  text-align: center;
  color: #fff;
}
.cta-band h2 {
  font-size: 2rem;
  font-weight: 800;
  margin-bottom: 12px;
  letter-spacing: -.3px;
}
.cta-band p {
  font-size: 1.05rem;
  opacity: .85;
  margin-bottom: 32px;
}

/* ===== STEP LIST ===== */
.step-list { counter-reset: step; display: flex; flex-direction: column; gap: 24px; }
.step-item { display: flex; gap: 18px; align-items: flex-start; }
.step-num {
  counter-increment: step;
  width: 36px; height: 36px;
  border-radius: 50%;
  background: var(--blue-deep);
  color: #fff;
  font-weight: 800;
  font-size: .88rem;
  display: flex;
  align-items: center;
  justify-content: center;
  flex-shrink: 0;
}
.step-num::after { content: counter(step); }
.step-text h4 { font-size: .97rem; font-weight: 700; margin-bottom: 4px; }
.step-text p { font-size: .88rem; color: var(--text-gray); }

/* ===== NOTICE STRIP ===== */
.notice-strip {
  background: #e6f4ea;
  border-left: 4px solid var(--green-safe);
  padding: 14px 20px;
  border-radius: 0 8px 8px 0;
  font-size: .9rem;
  color: #1e6e38;
  display: flex;
  align-items: center;
  gap: 10px;
}
.notice-strip i { font-size: 1.1rem; }

/* ===== RESPONSIVE ===== */
@media (max-width: 1024px) {
  .footer-top { grid-template-columns: 1fr 1fr; }
  .grid-4 { grid-template-columns: repeat(2,1fr); }
}
@media (max-width: 768px) {
  .main-nav { display: none; }
  .hamburger { display: block; }
  .hero-inner { grid-template-columns: 1fr; gap: 36px; }
  .hero-image { display: none; }
  .hero-text h1 { font-size: 2rem; }
  .section-title { font-size: 1.6rem; }
  .grid-2, .grid-3, .grid-4 { grid-template-columns: 1fr; }
  .footer-top { grid-template-columns: 1fr; gap: 28px; }
  .footer-bottom { flex-direction: column; align-items: flex-start; }
  .stats-inner { justify-content: center; }
  .section { padding: 48px 0; }
}
@media (max-width: 480px) {
  .topbar-inner { padding: 0 14px; }
  .container { padding: 0 14px; }
  .hero { padding: 60px 0 48px; }
  .hero-text h1 { font-size: 1.75rem; }
}

/* ===== ANIMATIONS ===== */
@keyframes fadeUp {
  from { opacity: 0; transform: translateY(24px); }
  to   { opacity: 1; transform: translateY(0); }
}
.fade-up { animation: fadeUp .55s ease both; }
.delay-1 { animation-delay: .1s; }
.delay-2 { animation-delay: .2s; }
.delay-3 { animation-delay: .3s; }