/* ===== 海鸥加速器 · 全局变量与基础样式 ===== */
:root {
  --color-bg: #0a1428;
  --color-bg-alt: #0d1a33;
  --color-surface: #10203d;
  --color-surface-2: #142848;
  --color-border: rgba(255, 255, 255, 0.08);
  --color-text: #eaf1ff;
  --color-text-muted: #9db0d1;
  --color-primary: #2f7dfa;
  --color-primary-dark: #1b5fd4;
  --color-accent: #ff8a4c;
  --color-accent-dark: #f06a28;
  --color-success: #34d1a6;
  --radius-sm: 10px;
  --radius-md: 16px;
  --radius-lg: 24px;
  --shadow-card: 0 12px 30px rgba(4, 10, 24, 0.35);
  --container-width: 1160px;
  --font-sans: "PingFang SC", "Microsoft YaHei", "Helvetica Neue", Arial, sans-serif;
}

* { box-sizing: border-box; }

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  font-family: var(--font-sans);
  background: var(--color-bg);
  color: var(--color-text);
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
}

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

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

ul, ol { list-style: none; margin: 0; padding: 0; }

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

h1, h2, h3 {
  margin: 0;
  font-weight: 700;
  line-height: 1.25;
}

h1 { font-size: clamp(2.1rem, 4vw, 3.2rem); }
h2 { font-size: clamp(1.6rem, 3vw, 2.3rem); }
h3 { font-size: 1.15rem; }

p { margin: 0; }

/* ===== 按钮 ===== */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 12px 24px;
  border-radius: 999px;
  font-weight: 600;
  font-size: 0.95rem;
  border: 1px solid transparent;
  cursor: pointer;
  transition: transform 0.2s ease, box-shadow 0.2s ease, background 0.2s ease;
  white-space: nowrap;
}
.btn-primary {
  background: linear-gradient(135deg, var(--color-accent), var(--color-accent-dark));
  color: #0a1428;
  box-shadow: 0 10px 24px rgba(255, 138, 76, 0.28);
}
.btn-primary:hover { transform: translateY(-2px); box-shadow: 0 14px 30px rgba(255, 138, 76, 0.38); }
.btn-outline {
  background: transparent;
  border-color: rgba(255, 255, 255, 0.24);
  color: var(--color-text);
}
.btn-outline:hover { border-color: var(--color-primary); background: rgba(47, 125, 250, 0.1); }
.btn-ghost {
  background: transparent;
  color: var(--color-text-muted);
}
.btn-ghost:hover { color: var(--color-text); }
.btn-lg { padding: 15px 30px; font-size: 1.02rem; }

/* ===== 顶部导航 ===== */
.site-header {
  position: sticky;
  top: 0;
  z-index: 100;
  background: rgba(10, 20, 40, 0.72);
  backdrop-filter: blur(14px);
  border-bottom: 1px solid var(--color-border);
  transition: background 0.3s ease;
}
.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 72px;
  gap: 24px;
}
.brand { display: flex; align-items: center; gap: 10px; }
.brand-name { font-size: 1.15rem; font-weight: 800; letter-spacing: 0.5px; }
.main-nav { display: flex; align-items: center; gap: 28px; flex: 1; justify-content: center; }
.main-nav a { color: var(--color-text-muted); font-size: 0.95rem; transition: color 0.2s ease; }
.main-nav a:hover { color: var(--color-text); }
.header-actions { display: flex; align-items: center; gap: 12px; }
.nav-toggle {
  display: none;
  flex-direction: column;
  justify-content: center;
  gap: 5px;
  width: 40px;
  height: 40px;
  background: transparent;
  border: 1px solid var(--color-border);
  border-radius: 10px;
  cursor: pointer;
}
.nav-toggle span {
  display: block;
  width: 18px;
  height: 2px;
  margin: 0 auto;
  background: var(--color-text);
  transition: transform 0.25s ease, opacity 0.25s ease;
}
.nav-toggle.open span:nth-child(1) { transform: translateY(7px) rotate(45deg); }
.nav-toggle.open span:nth-child(2) { opacity: 0; }
.nav-toggle.open span:nth-child(3) { transform: translateY(-7px) rotate(-45deg); }

/* ===== Hero ===== */
.hero {
  padding: 88px 0 70px;
  background:
    radial-gradient(1000px 500px at 85% -10%, rgba(47, 125, 250, 0.22), transparent 60%),
    radial-gradient(700px 400px at -5% 30%, rgba(255, 138, 76, 0.14), transparent 60%);
}
.hero-inner {
  display: grid;
  grid-template-columns: 1.05fr 0.95fr;
  align-items: center;
  gap: 48px;
}
.eyebrow {
  display: inline-block;
  color: var(--color-accent);
  font-weight: 700;
  font-size: 0.85rem;
  letter-spacing: 1px;
  margin-bottom: 14px;
}
.hero-desc {
  margin-top: 18px;
  color: var(--color-text-muted);
  font-size: 1.05rem;
  max-width: 520px;
}
.hero-cta { display: flex; gap: 16px; margin-top: 30px; flex-wrap: wrap; }
.hero-stats {
  display: flex;
  gap: 32px;
  margin-top: 44px;
  flex-wrap: wrap;
}
.hero-stats li { display: flex; flex-direction: column; gap: 4px; }
.hero-stats strong { font-size: 1.5rem; color: var(--color-primary); }
.hero-stats span { font-size: 0.85rem; color: var(--color-text-muted); }
.hero-visual { display: flex; justify-content: center; }

/* ===== Section 通用 ===== */
.section { padding: 96px 0; }
.section-alt { background: var(--color-bg-alt); }
.section-head { max-width: 640px; margin: 0 auto 52px; text-align: center; }
.section-desc { margin-top: 14px; color: var(--color-text-muted); font-size: 1rem; }

/* ===== 功能特色 ===== */
.feature-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 22px;
}
.feature-card {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  padding: 28px 24px;
  box-shadow: var(--shadow-card);
  transition: transform 0.25s ease, border-color 0.25s ease;
}
.feature-card:hover { transform: translateY(-4px); border-color: rgba(47, 125, 250, 0.4); }
.feature-card img { margin-bottom: 18px; }
.feature-card h3 { margin-bottom: 10px; }
.feature-card p { color: var(--color-text-muted); font-size: 0.92rem; }

/* ===== 使用流程 ===== */
.steps {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 28px;
  counter-reset: step;
}
.step {
  position: relative;
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  padding: 34px 28px;
}
.step-num {
  display: inline-block;
  font-size: 1.6rem;
  font-weight: 800;
  color: var(--color-primary);
  margin-bottom: 14px;
}
.step h3 { margin-bottom: 10px; }
.step p { color: var(--color-text-muted); font-size: 0.92rem; }

/* ===== 价格方案 ===== */
.pricing-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 22px;
  align-items: stretch;
}
.price-card {
  position: relative;
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  padding: 32px 26px;
  display: flex;
  flex-direction: column;
  gap: 16px;
}
.price-card-featured {
  background: linear-gradient(165deg, var(--color-surface-2), var(--color-surface));
  border-color: var(--color-primary);
  transform: translateY(-8px);
  box-shadow: 0 20px 40px rgba(47, 125, 250, 0.25);
}
.price-badge {
  position: absolute;
  top: -14px;
  left: 50%;
  transform: translateX(-50%);
  background: var(--color-primary);
  color: #fff;
  font-size: 0.75rem;
  padding: 5px 14px;
  border-radius: 999px;
  font-weight: 700;
}
.price { display: flex; align-items: baseline; gap: 6px; }
.price-num { font-size: 2.1rem; font-weight: 800; }
.price-unit { color: var(--color-text-muted); font-size: 0.9rem; }
.price-list { display: flex; flex-direction: column; gap: 10px; flex: 1; }
.price-list li {
  color: var(--color-text-muted);
  font-size: 0.9rem;
  padding-left: 22px;
  position: relative;
}
.price-list li::before {
  content: "";
  position: absolute;
  left: 0;
  top: 7px;
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background: var(--color-success);
}
.price-card .btn { margin-top: 8px; }

/* ===== 数据 & 用户评价 ===== */
.stats-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 22px;
  margin-bottom: 52px;
}
.stat-card {
  text-align: center;
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  padding: 30px 16px;
}
.stat-card strong { display: block; font-size: 2rem; color: var(--color-accent); margin-bottom: 8px; }
.stat-card span { color: var(--color-text-muted); font-size: 0.88rem; }

.testimonial-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 22px;
}
.testimonial {
  margin: 0;
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  padding: 28px 24px;
}
.testimonial p { color: var(--color-text); font-size: 0.95rem; }
.testimonial footer { margin-top: 16px; color: var(--color-text-muted); font-size: 0.85rem; }

/* ===== FAQ ===== */
.faq-list { max-width: 780px; margin: 0 auto; display: flex; flex-direction: column; gap: 14px; }
.faq-item {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-sm);
  overflow: hidden;
}
.faq-question {
  width: 100%;
  text-align: left;
  background: transparent;
  border: none;
  color: var(--color-text);
  font-size: 1rem;
  font-weight: 600;
  padding: 20px 24px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  cursor: pointer;
}
.faq-icon {
  flex-shrink: 0;
  width: 20px;
  height: 20px;
  position: relative;
}
.faq-icon::before, .faq-icon::after {
  content: "";
  position: absolute;
  background: var(--color-primary);
  transition: transform 0.25s ease;
}
.faq-icon::before { width: 100%; height: 2px; top: 9px; left: 0; }
.faq-icon::after { width: 2px; height: 100%; top: 0; left: 9px; }
.faq-question[aria-expanded="true"] .faq-icon::after { transform: rotate(90deg); opacity: 0; }
.faq-answer {
  max-height: 0;
  overflow: hidden;
  transition: max-height 0.3s ease;
}
.faq-answer p { padding: 0 24px 20px; color: var(--color-text-muted); font-size: 0.92rem; }

/* ===== CTA 横幅 ===== */
.cta-band {
  padding: 70px 0;
  background: linear-gradient(120deg, rgba(47, 125, 250, 0.16), rgba(255, 138, 76, 0.12));
  border-top: 1px solid var(--color-border);
  border-bottom: 1px solid var(--color-border);
}
.cta-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 24px;
  flex-wrap: wrap;
}
.cta-inner p { color: var(--color-text-muted); margin-top: 10px; }

/* ===== 页脚 ===== */
.site-footer { background: var(--color-bg-alt); padding-top: 64px; border-top: 1px solid var(--color-border); }
.footer-inner {
  display: grid;
  grid-template-columns: 1.6fr repeat(4, 1fr);
  gap: 32px;
  padding-bottom: 40px;
}
.footer-brand p { margin-top: 14px; color: var(--color-text-muted); font-size: 0.88rem; max-width: 260px; }
.footer-col { display: flex; flex-direction: column; gap: 12px; }
.footer-col h4 { color: var(--color-text); font-size: 0.95rem; margin-bottom: 4px; }
.footer-col a { color: var(--color-text-muted); font-size: 0.88rem; transition: color 0.2s ease; }
.footer-col a:hover { color: var(--color-text); }
.footer-bottom {
  border-top: 1px solid var(--color-border);
  padding: 22px 24px;
  display: flex;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 8px;
  color: var(--color-text-muted);
  font-size: 0.82rem;
}

/* ===== 响应式 ===== */
@media (max-width: 980px) {
  .feature-grid { grid-template-columns: repeat(2, 1fr); }
  .pricing-grid { grid-template-columns: repeat(2, 1fr); }
  .price-card-featured { transform: none; }
  .stats-grid { grid-template-columns: repeat(2, 1fr); }
  .testimonial-grid { grid-template-columns: 1fr; }
  .steps { grid-template-columns: 1fr; }
  .footer-inner { grid-template-columns: repeat(2, 1fr); }
  .hero-inner { grid-template-columns: 1fr; }
  .hero-visual { order: -1; }
}

@media (max-width: 720px) {
  .main-nav, .header-actions { display: none; }
  .nav-toggle { display: flex; }
  .site-header.nav-open .main-nav {
    display: flex;
    flex-direction: column;
    position: absolute;
    top: 72px;
    left: 0;
    right: 0;
    background: var(--color-bg);
    padding: 20px 24px;
    border-bottom: 1px solid var(--color-border);
    gap: 18px;
  }
  .site-header.nav-open .header-actions {
    display: flex;
    position: absolute;
    top: calc(72px + 210px);
    left: 0;
    right: 0;
    background: var(--color-bg);
    padding: 0 24px 20px;
    gap: 12px;
  }
  .feature-grid { grid-template-columns: 1fr; }
  .pricing-grid { grid-template-columns: 1fr; }
  .stats-grid { grid-template-columns: 1fr 1fr; }
  .footer-inner { grid-template-columns: 1fr; }
  .cta-inner { flex-direction: column; align-items: flex-start; }
}