/* ============ 基础重置与变量 ============ */
:root {
  --brand: #e63946;
  --brand-dark: #c62835;
  --brand-light: #ff6b6b;
  --bg: #0f1420;
  --bg-soft: #161d2b;
  --bg-card: #1b2436;
  --text: #eef1f6;
  --text-muted: #9aa4b5;
  --border: #2a3447;
  --radius: 14px;
  --radius-lg: 20px;
  --shadow: 0 18px 50px rgba(0, 0, 0, 0.45);
}

* { margin: 0; padding: 0; box-sizing: border-box; }

html { scroll-behavior: smooth; }

body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC",
    "Hiragino Sans GB", "Microsoft YaHei", "Helvetica Neue", Arial, sans-serif;
  background: var(--bg);
  color: var(--text);
  line-height: 1.7;
  -webkit-font-smoothing: antialiased;
}

a { text-decoration: none; color: inherit; }
ul { list-style: none; }
code {
  background: rgba(230, 57, 70, 0.14);
  color: #ff8a94;
  padding: 2px 7px;
  border-radius: 5px;
  font-family: "Consolas", "Monaco", monospace;
  font-size: 0.9em;
}

.container {
  width: 100%;
  max-width: 1100px;
  margin: 0 auto;
  padding: 0 24px;
}

/* ============ 顶部导航 ============ */
.site-header {
  position: sticky;
  top: 0;
  z-index: 100;
  background: rgba(15, 20, 32, 0.82);
  backdrop-filter: blur(14px);
  -webkit-backdrop-filter: blur(14px);
  border-bottom: 1px solid var(--border);
}

.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 68px;
}

.logo { display: flex; align-items: center; gap: 10px; }

.logo-icon {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 38px;
  height: 38px;
  background: linear-gradient(135deg, var(--brand), var(--brand-dark));
  border-radius: 10px;
  font-weight: 800;
  font-size: 22px;
  color: #fff;
  box-shadow: 0 6px 16px rgba(230, 57, 70, 0.4);
}

.logo-text { font-size: 20px; font-weight: 700; letter-spacing: -0.3px; }
.logo-text em { font-style: normal; color: var(--brand); font-size: 16px; margin-left: 2px; }

.logo-slogan {
  font-size: 13px;
  color: var(--text-muted);
  margin-left: 6px;
  padding-left: 12px;
  border-left: 1px solid var(--border);
  white-space: nowrap;
}

.main-nav { display: flex; align-items: center; gap: 28px; }

.nav-link {
  font-size: 15px;
  color: var(--text-muted);
  transition: color 0.2s;
  position: relative;
}
.nav-link:hover, .nav-link.active { color: var(--text); }
.nav-link.active::after {
  content: "";
  position: absolute;
  left: 0; right: 0; bottom: -8px;
  height: 2px;
  background: var(--brand);
  border-radius: 2px;
}

.nav-cta {
  background: var(--brand);
  color: #fff !important;
  padding: 8px 20px;
  border-radius: 20px;
  font-weight: 600;
  transition: background 0.2s, transform 0.15s;
}
.nav-cta:hover { background: var(--brand-dark); transform: translateY(-1px); }
.nav-cta.active::after { display: none; }

.nav-toggle { display: none; background: none; border: none; cursor: pointer; }
.nav-toggle span {
  display: block;
  width: 24px; height: 2px;
  background: var(--text);
  margin: 5px 0;
  border-radius: 2px;
  transition: 0.3s;
}

/* ============ Hero 区 ============ */
.hero {
  position: relative;
  padding: 90px 0 80px;
  text-align: center;
  background:
    radial-gradient(ellipse 800px 500px at 50% -10%, rgba(230, 57, 70, 0.22), transparent 65%),
    radial-gradient(ellipse 600px 400px at 85% 10%, rgba(255, 107, 107, 0.10), transparent 60%);
}

.hero-badge {
  display: inline-block;
  background: rgba(230, 57, 70, 0.14);
  color: var(--brand-light);
  border: 1px solid rgba(230, 57, 70, 0.35);
  padding: 6px 18px;
  border-radius: 20px;
  font-size: 14px;
  margin-bottom: 26px;
}

.hero-title {
  font-size: clamp(44px, 8vw, 76px);
  font-weight: 800;
  letter-spacing: -1px;
  line-height: 1.1;
  margin-bottom: 16px;
}
.title-dot { color: var(--brand); }

.hero-slogan {
  font-size: clamp(20px, 3vw, 28px);
  font-weight: 600;
  color: var(--text);
  margin-bottom: 8px;
}

.hero-sub {
  font-size: 17px;
  color: var(--text-muted);
  margin-bottom: 40px;
}

.download-btns {
  display: flex;
  justify-content: center;
  gap: 20px;
  flex-wrap: wrap;
  margin-bottom: 32px;
}

.btn {
  display: flex;
  flex-direction: column;
  align-items: center;
  padding: 16px 34px;
  border-radius: var(--radius);
  font-weight: 600;
  transition: transform 0.18s, box-shadow 0.18s, background 0.2s;
  min-width: 230px;
}
.btn:hover { transform: translateY(-3px); }

.btn-primary {
  background: linear-gradient(135deg, var(--brand), var(--brand-dark));
  color: #fff;
  box-shadow: 0 10px 28px rgba(230, 57, 70, 0.42);
}
.btn-primary:hover { box-shadow: 0 14px 36px rgba(230, 57, 70, 0.55); }

.btn-secondary {
  background: var(--bg-card);
  color: var(--text);
  border: 1px solid var(--border);
  box-shadow: var(--shadow);
}
.btn-secondary:hover { border-color: var(--brand); }

.btn-light {
  background: #fff;
  color: var(--brand-dark);
  box-shadow: 0 10px 28px rgba(0, 0, 0, 0.35);
}

.btn-main { font-size: 17px; }
.btn-sub { font-size: 12px; font-weight: 400; opacity: 0.82; margin-top: 3px; }

.hero-points {
  display: flex;
  justify-content: center;
  gap: 30px;
  flex-wrap: wrap;
  color: var(--text-muted);
  font-size: 14px;
}
.hero-points li { display: flex; align-items: center; gap: 6px; }

/* ============ 功能特性 ============ */
.features { padding: 80px 0; background: var(--bg-soft); }

.section-title {
  text-align: center;
  font-size: clamp(28px, 4vw, 38px);
  font-weight: 700;
  margin-bottom: 8px;
}
.section-sub {
  text-align: center;
  color: var(--text-muted);
  font-size: 16px;
  margin-bottom: 48px;
}

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

.feature-card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: 30px 24px;
  transition: transform 0.2s, border-color 0.2s;
}
.feature-card:hover { transform: translateY(-5px); border-color: var(--brand); }

.feature-icon {
  font-size: 36px;
  margin-bottom: 16px;
  display: inline-block;
}
.feature-card h3 { font-size: 18px; margin-bottom: 10px; }
.feature-card p { font-size: 14px; color: var(--text-muted); }

.feature-points {
  margin-top: 14px;
  padding-top: 14px;
  border-top: 1px solid var(--border);
}
.feature-points li {
  font-size: 13px;
  color: var(--text-muted);
  padding: 4px 0 4px 18px;
  position: relative;
}
.feature-points li::before {
  content: "✓";
  position: absolute;
  left: 0;
  color: var(--brand);
  font-weight: 700;
}

/* ============ FAQ ============ */
.faq { padding: 80px 0; }

.faq-list {
  max-width: 820px;
  margin: 0 auto;
  display: flex;
  flex-direction: column;
  gap: 14px;
}

.faq-item {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  overflow: hidden;
  transition: border-color 0.2s;
}
.faq-item.open { border-color: var(--brand); }

.faq-question {
  width: 100%;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  padding: 20px 24px;
  background: none;
  border: none;
  cursor: pointer;
  color: var(--text);
  font-size: 16px;
  font-weight: 600;
  text-align: left;
  font-family: inherit;
}

.faq-icon {
  flex-shrink: 0;
  width: 26px; height: 26px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  border-radius: 50%;
  background: rgba(230, 57, 70, 0.14);
  color: var(--brand-light);
  font-size: 18px;
  transition: transform 0.25s;
}
.faq-item.open .faq-icon { transform: rotate(45deg); }

.faq-answer {
  max-height: 0;
  overflow: hidden;
  transition: max-height 0.32s ease;
}
.faq-answer > * { padding: 0 24px; }
.faq-answer p { color: var(--text-muted); font-size: 15px; }
.faq-answer .faq-lead {
  color: var(--text);
  font-weight: 600;
  font-size: 15.5px;
  margin-bottom: 8px;
  padding-top: 2px;
}
.faq-answer p:last-child { padding-bottom: 22px; }
.faq-answer ul { padding-bottom: 22px; color: var(--text-muted); font-size: 15px; }
.faq-answer ul li {
  padding: 5px 0 5px 20px;
  position: relative;
}
.faq-answer ul li::before {
  content: "•";
  position: absolute;
  left: 4px;
  color: var(--brand);
}

/* ============ CTA ============ */
.cta-band {
  background: linear-gradient(135deg, var(--brand), var(--brand-dark));
  padding: 60px 0;
}
.cta-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 30px;
  flex-wrap: wrap;
}
.cta-inner h2 { font-size: 26px; margin-bottom: 6px; }
.cta-inner p { color: rgba(255, 255, 255, 0.85); }

/* ============ 页脚 ============ */
.site-footer { background: #0b1019; padding-top: 56px; }

.footer-inner {
  display: flex;
  justify-content: space-between;
  gap: 40px;
  flex-wrap: wrap;
  padding-bottom: 40px;
}

.footer-brand .logo-text { display: inline-block; margin-bottom: 10px; }
.footer-brand p { color: var(--text-muted); font-size: 14px; margin-top: 12px; }
.footer-brand .logo-icon { margin-right: 8px; }

.footer-links { display: flex; gap: 60px; flex-wrap: wrap; }

.footer-col h4 { font-size: 15px; margin-bottom: 14px; color: var(--text); }
.footer-col a {
  display: block;
  color: var(--text-muted);
  font-size: 14px;
  padding: 5px 0;
  transition: color 0.2s;
}
.footer-col a:hover { color: var(--brand-light); }

.footer-bottom {
  border-top: 1px solid var(--border);
  padding: 18px 0;
}
.footer-bottom p {
  text-align: center;
  color: var(--text-muted);
  font-size: 13px;
}

/* ============ 响应式 ============ */
@media (max-width: 900px) {
  .features-grid { grid-template-columns: repeat(2, 1fr); }
}

@media (max-width: 720px) {
  .nav-toggle { display: block; }
  .main-nav {
    position: absolute;
    top: 68px; left: 0; right: 0;
    flex-direction: column;
    align-items: flex-start;
    gap: 0;
    background: var(--bg);
    border-bottom: 1px solid var(--border);
    padding: 10px 24px 20px;
    display: none;
  }
  .main-nav.show { display: flex; }
  .nav-link { padding: 12px 0; width: 100%; border-bottom: 1px solid var(--border); }
  .nav-link.active::after { display: none; }
  .nav-cta { margin-top: 14px; text-align: center; width: 100%; border-radius: var(--radius); }

  .hero { padding: 60px 0; }
  .download-btns { flex-direction: column; align-items: center; }
  .btn { width: 100%; max-width: 340px; }

  .features-grid { grid-template-columns: 1fr; }
  .cta-inner { flex-direction: column; text-align: center; }
}