/* ===== Reset & Base ===== */
*, *::before, *::after { margin: 0; padding: 0; box-sizing: border-box; }
html { scroll-behavior: smooth; font-size: 16px; }
body {
  font-family: "Source Han Sans SC", "PingFang SC", "Inter", "SF Pro", -apple-system, BlinkMacSystemFont, sans-serif;
  color: #333; background: #fff; line-height: 1.6; overflow-x: hidden;
}
a { text-decoration: none; color: inherit; transition: color .2s; }
img { max-width: 100%; display: block; }
ul, ol { list-style: none; }

/* ===== Utility ===== */
.container { max-width: 1200px; margin: 0 auto; padding: 0 20px; }
.section-title { text-align: center; font-size: 2rem; font-weight: 700; margin-bottom: 12px; color: #1a1a2e; }
.section-subtitle { text-align: center; font-size: 1.05rem; color: #666; margin-bottom: 48px; }
.btn-primary {
  display: inline-block; padding: 14px 36px; background: linear-gradient(135deg, #1a73e8, #0d5bd1);
  color: #fff; border-radius: 10px; font-size: 1.05rem; font-weight: 600;
  transition: transform .2s, box-shadow .2s; box-shadow: 0 4px 15px rgba(26,115,232,.3);
}
.btn-primary:hover { transform: translateY(-2px); box-shadow: 0 6px 20px rgba(26,115,232,.45); color: #fff; }
.btn-outline {
  display: inline-block; padding: 12px 28px; border: 2px solid #1a73e8;
  color: #1a73e8; border-radius: 10px; font-size: 1rem; font-weight: 600;
  transition: background .2s, color .2s;
}
.btn-outline:hover { background: #1a73e8; color: #fff; }

/* ===== Navigation ===== */
.navbar {
  position: fixed; top: 0; left: 0; width: 100%; z-index: 1000;
  background: rgba(255,255,255,.95); backdrop-filter: blur(10px);
  border-bottom: 1px solid rgba(0,0,0,.06); transition: background .3s;
}
.navbar .container { display: flex; align-items: center; justify-content: space-between; height: 70px; }
.nav-brand { display: flex; align-items: center; gap: 10px; font-size: 1.4rem; font-weight: 700; color: #1a73e8; }
.nav-brand img { width: 36px; height: 36px; }
.nav-links { display: flex; align-items: center; gap: 32px; }
.nav-links a { font-size: .95rem; color: #555; font-weight: 500; transition: color .2s; }
.nav-links a:hover, .nav-links a.active { color: #1a73e8; }
.nav-cta { margin-left: 12px; }
.nav-cta .btn-primary { padding: 10px 24px; font-size: .9rem; }
.nav-toggle { display: none; flex-direction: column; gap: 5px; cursor: pointer; padding: 8px; }
.nav-toggle span { display: block; width: 24px; height: 2px; background: #333; border-radius: 2px; }

/* ===== Hero ===== */
.hero {
  position: relative; min-height: 100vh; display: flex; align-items: center; justify-content: center;
  text-align: center; padding: 120px 20px 80px;
  background: linear-gradient(135deg, #0a1628 0%, #1a2a4a 40%, #0d3b66 100%);
  overflow: hidden;
}
.hero::before {
  content: ''; position: absolute; inset: 0;
  background:
    radial-gradient(circle at 20% 50%, rgba(26,115,232,.15) 0%, transparent 50%),
    radial-gradient(circle at 80% 20%, rgba(0,200,255,.1) 0%, transparent 40%),
    radial-gradient(circle at 60% 80%, rgba(26,115,232,.08) 0%, transparent 40%);
}
.hero-content { position: relative; z-index: 2; max-width: 800px; }
.hero h1 { font-size: 3.2rem; font-weight: 800; color: #fff; margin-bottom: 20px; line-height: 1.2; }
.hero h1 span { color: #4fc3f7; }
.hero p { font-size: 1.2rem; color: rgba(255,255,255,.8); margin-bottom: 36px; line-height: 1.7; }
.hero-badges { display: flex; justify-content: center; gap: 24px; margin-top: 32px; flex-wrap: wrap; }
.hero-badge {
  display: flex; align-items: center; gap: 8px; padding: 8px 18px;
  background: rgba(255,255,255,.1); border-radius: 20px; color: rgba(255,255,255,.9);
  font-size: .9rem; backdrop-filter: blur(5px); border: 1px solid rgba(255,255,255,.15);
}
.hero-badge svg { width: 18px; height: 18px; fill: #4fc3f7; }

/* ===== Highlights ===== */
.highlights { padding: 100px 0; background: #f8fafc; }
.highlights-grid { display: grid; grid-template-columns: repeat(4, 1fr); gap: 30px; }
.highlight-card {
  background: #fff; border-radius: 16px; padding: 40px 28px; text-align: center;
  box-shadow: 0 2px 12px rgba(0,0,0,.05); transition: transform .3s, box-shadow .3s;
  border: 1px solid rgba(0,0,0,.04);
}
.highlight-card:hover { transform: translateY(-6px); box-shadow: 0 8px 30px rgba(0,0,0,.1); }
.highlight-icon {
  width: 64px; height: 64px; margin: 0 auto 20px; border-radius: 16px;
  display: flex; align-items: center; justify-content: center;
  background: linear-gradient(135deg, #e3f2fd, #bbdefb);
}
.highlight-icon svg { width: 32px; height: 32px; fill: #1a73e8; }
.highlight-card h3 { font-size: 1.2rem; font-weight: 700; margin-bottom: 10px; color: #1a1a2e; }
.highlight-card p { font-size: .95rem; color: #666; line-height: 1.6; }

/* ===== Scenarios ===== */
.scenarios { padding: 100px 0; }
.scenarios-grid { display: grid; grid-template-columns: repeat(4, 1fr); gap: 24px; }
.scenario-card {
  border-radius: 16px; overflow: hidden; background: #fff;
  box-shadow: 0 2px 12px rgba(0,0,0,.06); transition: transform .3s;
  border: 1px solid rgba(0,0,0,.05);
}
.scenario-card:hover { transform: translateY(-4px); }
.scenario-img {
  height: 180px; display: flex; align-items: center; justify-content: center;
  font-size: 3.5rem;
}
.scenario-img.office { background: linear-gradient(135deg, #e3f2fd, #e8eaf6); }
.scenario-img.study { background: linear-gradient(135deg, #e8f5e9, #e0f7fa); }
.scenario-img.game { background: linear-gradient(135deg, #fce4ec, #f3e5f5); }
.scenario-img.mobile { background: linear-gradient(135deg, #fff3e0, #fff8e1); }
.scenario-body { padding: 24px; }
.scenario-body h3 { font-size: 1.15rem; font-weight: 700; margin-bottom: 8px; color: #1a1a2e; }
.scenario-body p { font-size: .9rem; color: #666; line-height: 1.6; }

/* ===== Guide Preview ===== */
.guide-preview { padding: 100px 0; background: #f8fafc; }
.steps-row { display: flex; justify-content: center; gap: 48px; flex-wrap: wrap; }
.step-item { text-align: center; max-width: 260px; }
.step-num {
  width: 60px; height: 60px; margin: 0 auto 16px; border-radius: 50%;
  background: linear-gradient(135deg, #1a73e8, #0d5bd1); color: #fff;
  display: flex; align-items: center; justify-content: center;
  font-size: 1.5rem; font-weight: 800; box-shadow: 0 4px 15px rgba(26,115,232,.3);
}
.step-item h3 { font-size: 1.1rem; font-weight: 700; margin-bottom: 8px; color: #1a1a2e; }
.step-item p { font-size: .9rem; color: #666; }
.guide-cta { text-align: center; margin-top: 48px; }

/* ===== Download Section ===== */
.download-section { padding: 100px 0; }
.download-grid { display: grid; grid-template-columns: repeat(4, 1fr); gap: 24px; margin-bottom: 24px; }
.download-card {
  background: #fff; border-radius: 16px; padding: 36px 24px; text-align: center;
  box-shadow: 0 2px 12px rgba(0,0,0,.06); border: 1px solid rgba(0,0,0,.05);
  transition: transform .3s, box-shadow .3s;
}
.download-card:hover { transform: translateY(-4px); box-shadow: 0 8px 24px rgba(0,0,0,.1); }
.download-card .platform-icon { font-size: 2.8rem; margin-bottom: 16px; }
.download-card h3 { font-size: 1.1rem; font-weight: 700; margin-bottom: 6px; }
.download-card .version { font-size: .8rem; color: #999; margin-bottom: 16px; }
.download-card .btn-primary { padding: 10px 24px; font-size: .9rem; width: 100%; }
.download-notice { text-align: center; color: #999; font-size: .85rem; margin-top: 12px; }

/* ===== Trust ===== */
.trust { padding: 80px 0; background: linear-gradient(135deg, #0a1628, #1a2a4a); color: #fff; }
.trust .section-title { color: #fff; }
.trust .section-subtitle { color: rgba(255,255,255,.7); }
.trust-stats { display: flex; justify-content: center; gap: 60px; flex-wrap: wrap; margin-bottom: 48px; }
.trust-stat { text-align: center; }
.trust-stat .num { font-size: 2.8rem; font-weight: 800; color: #4fc3f7; }
.trust-stat .label { font-size: .95rem; color: rgba(255,255,255,.7); margin-top: 4px; }
.trust-badges { display: flex; justify-content: center; gap: 32px; flex-wrap: wrap; }
.trust-badge {
  display: flex; align-items: center; gap: 8px; padding: 10px 20px;
  background: rgba(255,255,255,.08); border-radius: 10px; font-size: .9rem;
  color: rgba(255,255,255,.85); border: 1px solid rgba(255,255,255,.1);
}
.trust-badge svg { width: 20px; height: 20px; fill: #4fc3f7; }

/* ===== FAQ ===== */
.faq { padding: 100px 0; background: #f8fafc; }
.faq-list { max-width: 800px; margin: 0 auto; }
.faq-item {
  background: #fff; border-radius: 12px; margin-bottom: 16px;
  box-shadow: 0 1px 6px rgba(0,0,0,.04); border: 1px solid rgba(0,0,0,.05);
  overflow: hidden;
}
.faq-item details { padding: 0; }
.faq-item summary {
  padding: 20px 24px; font-size: 1.05rem; font-weight: 600; cursor: pointer;
  color: #1a1a2e; list-style: none; display: flex; justify-content: space-between; align-items: center;
}
.faq-item summary::-webkit-details-marker { display: none; }
.faq-item summary::after { content: '+'; font-size: 1.4rem; color: #1a73e8; font-weight: 300; transition: transform .2s; }
.faq-item details[open] summary::after { content: '-'; }
.faq-answer { padding: 0 24px 20px; color: #555; line-height: 1.8; }
.faq-answer ol { padding-left: 20px; list-style: decimal; }
.faq-answer ol li { margin-bottom: 8px; }

/* ===== Footer ===== */
.footer { padding: 60px 0 30px; background: #0a1628; color: rgba(255,255,255,.7); }
.footer-grid { display: grid; grid-template-columns: 2fr 1fr 1fr 1fr; gap: 40px; margin-bottom: 40px; }
.footer-brand h3 { font-size: 1.3rem; color: #fff; margin-bottom: 12px; }
.footer-brand p { font-size: .9rem; line-height: 1.7; }
.footer-col h4 { font-size: 1rem; color: #fff; margin-bottom: 16px; font-weight: 600; }
.footer-col a { display: block; font-size: .9rem; color: rgba(255,255,255,.6); margin-bottom: 10px; transition: color .2s; }
.footer-col a:hover { color: #4fc3f7; }
.footer-bottom {
  border-top: 1px solid rgba(255,255,255,.1); padding-top: 24px;
  display: flex; justify-content: space-between; align-items: center; flex-wrap: wrap; gap: 12px;
  font-size: .85rem;
}

/* ===== Sub Pages ===== */
.page-header {
  padding: 140px 0 60px; text-align: center;
  background: linear-gradient(135deg, #0a1628, #1a2a4a); color: #fff;
}
.page-header h1 { font-size: 2.4rem; font-weight: 800; margin-bottom: 12px; }
.page-header p { font-size: 1.1rem; color: rgba(255,255,255,.7); }
.page-content { padding: 80px 0; }
.content-block { max-width: 800px; margin: 0 auto; }
.content-block h2 { font-size: 1.6rem; font-weight: 700; color: #1a1a2e; margin: 40px 0 16px; }
.content-block h3 { font-size: 1.2rem; font-weight: 600; color: #333; margin: 28px 0 12px; }
.content-block p { font-size: 1rem; color: #555; line-height: 1.8; margin-bottom: 16px; }
.content-block ul, .content-block ol { padding-left: 24px; margin-bottom: 16px; }
.content-block ul li, .content-block ol li { margin-bottom: 8px; color: #555; line-height: 1.7; }
.content-block ul { list-style: disc; }
.content-block ol { list-style: decimal; }

/* ===== Features Page ===== */
.feature-detail { padding: 60px 0; }
.feature-row {
  display: flex; align-items: center; gap: 60px; margin-bottom: 80px;
  padding: 48px; background: #fff; border-radius: 20px;
  box-shadow: 0 2px 16px rgba(0,0,0,.05);
}
.feature-row:nth-child(even) { flex-direction: row-reverse; }
.feature-text { flex: 1; }
.feature-text h2 { font-size: 1.8rem; font-weight: 700; color: #1a1a2e; margin-bottom: 16px; }
.feature-text p { font-size: 1rem; color: #555; line-height: 1.8; margin-bottom: 12px; }
.feature-visual {
  flex: 1; height: 280px; border-radius: 16px;
  display: flex; align-items: center; justify-content: center; font-size: 5rem;
}
.feature-visual.v1 { background: linear-gradient(135deg, #e3f2fd, #bbdefb); }
.feature-visual.v2 { background: linear-gradient(135deg, #e8f5e9, #c8e6c9); }
.feature-visual.v3 { background: linear-gradient(135deg, #fce4ec, #f8bbd0); }
.feature-visual.v4 { background: linear-gradient(135deg, #fff3e0, #ffe0b2); }

/* ===== Download Page ===== */
.download-page-grid { display: grid; grid-template-columns: repeat(2, 1fr); gap: 30px; max-width: 800px; margin: 0 auto; }
.download-page-card {
  background: #fff; border-radius: 16px; padding: 40px; text-align: center;
  box-shadow: 0 2px 12px rgba(0,0,0,.06); border: 1px solid rgba(0,0,0,.05);
}
.download-page-card .platform-icon { font-size: 3.5rem; margin-bottom: 16px; }
.download-page-card h3 { font-size: 1.3rem; font-weight: 700; margin-bottom: 8px; }
.download-page-card .version { font-size: .85rem; color: #999; margin-bottom: 20px; }
.download-page-card .btn-primary { width: 100%; }

/* ===== Guide Page ===== */
.guide-steps { max-width: 800px; margin: 0 auto; }
.guide-step {
  display: flex; gap: 24px; margin-bottom: 40px; padding: 32px;
  background: #fff; border-radius: 16px; box-shadow: 0 2px 12px rgba(0,0,0,.05);
}
.guide-step-num {
  width: 50px; height: 50px; min-width: 50px; border-radius: 50%;
  background: linear-gradient(135deg, #1a73e8, #0d5bd1); color: #fff;
  display: flex; align-items: center; justify-content: center;
  font-size: 1.3rem; font-weight: 800;
}
.guide-step-content h3 { font-size: 1.2rem; font-weight: 700; margin-bottom: 8px; color: #1a1a2e; }
.guide-step-content p { font-size: .95rem; color: #555; line-height: 1.7; }

/* ===== About Page ===== */
.about-stats { display: grid; grid-template-columns: repeat(3, 1fr); gap: 30px; margin: 40px 0; }
.about-stat {
  text-align: center; padding: 32px; background: #f8fafc; border-radius: 16px;
}
.about-stat .num { font-size: 2.4rem; font-weight: 800; color: #1a73e8; }
.about-stat .label { font-size: .95rem; color: #666; margin-top: 4px; }

/* ===== Responsive ===== */
@media (max-width: 1024px) {
  .highlights-grid, .scenarios-grid, .download-grid { grid-template-columns: repeat(2, 1fr); }
  .footer-grid { grid-template-columns: repeat(2, 1fr); }
  .feature-row, .feature-row:nth-child(even) { flex-direction: column; }
  .feature-visual { width: 100%; }
}
@media (max-width: 768px) {
  .nav-links { display: none; }
  .nav-toggle { display: flex; }
  .nav-links.open {
    display: flex; flex-direction: column; position: absolute;
    top: 70px; left: 0; width: 100%; background: #fff;
    padding: 20px; gap: 16px; box-shadow: 0 4px 12px rgba(0,0,0,.1);
  }
  .hero h1 { font-size: 2.2rem; }
  .hero p { font-size: 1rem; }
  .highlights-grid, .scenarios-grid, .download-grid { grid-template-columns: 1fr; }
  .download-page-grid { grid-template-columns: 1fr; }
  .steps-row { flex-direction: column; align-items: center; }
  .trust-stats { gap: 30px; }
  .footer-grid { grid-template-columns: 1fr; }
  .about-stats { grid-template-columns: 1fr; }
  .section-title { font-size: 1.6rem; }
  .guide-step { flex-direction: column; }
}