/* ===== 快连加速器电脑版 - 全站样式 ===== */
* { margin: 0; padding: 0; box-sizing: border-box; }

:root {
  --primary: #2563eb;
  --primary-dark: #1d4ed8;
  --text: #1f2937;
  --text-light: #6b7280;
  --bg: #ffffff;
  --bg-gray: #f5f7fa;
  --border: #e5e7eb;
  --radius: 10px;
}

body {
  font-family: "Microsoft YaHei", "PingFang SC", sans-serif;
  color: var(--text);
  background: var(--bg);
  line-height: 1.7;
}

a { text-decoration: none; color: inherit; }
img { max-width: 100%; }
.container { width: 90%; max-width: 1100px; margin: 0 auto; }

/* ===== 顶部导航 ===== */
.header {
  position: sticky; top: 0; z-index: 100;
  background: var(--bg);
  border-bottom: 1px solid var(--border);
}
.header-inner {
  display: flex; align-items: center; justify-content: space-between;
  height: 64px;
}
.logo {
  font-size: 20px; font-weight: 700; color: var(--primary);
}
.logo span { color: var(--text); }
.nav { display: flex; gap: 28px; }
.nav a { font-size: 15px; color: var(--text-light); padding: 6px 0; }
.nav a:hover, .nav a.active { color: var(--primary); font-weight: 600; }
.nav-toggle { display: none; background: none; border: none; font-size: 24px; cursor: pointer; color: var(--text); }

/* ===== 按钮与标签 ===== */
.btn {
  display: inline-block; padding: 12px 32px; border-radius: var(--radius);
  font-size: 16px; font-weight: 600; text-align: center; transition: 0.2s;
}
.btn-primary { background: var(--primary); color: #fff; }
.btn-primary:hover { background: var(--primary-dark); }
.btn-outline { border: 1px solid var(--primary); color: var(--primary); }
.btn-outline:hover { background: #eff6ff; }
.btn-lg { padding: 16px 48px; font-size: 18px; }

.tag {
  display: inline-block; padding: 4px 14px; border-radius: 999px;
  background: #eff6ff; color: var(--primary); font-size: 13px; margin-bottom: 12px;
}

/* ===== 首屏 Banner ===== */
.hero {
  background: linear-gradient(135deg, #eff6ff 0%, #dbeafe 100%);
  text-align: center; padding: 80px 0;
}
.hero h1 { font-size: 40px; margin-bottom: 16px; }
.hero p { font-size: 18px; color: var(--text-light); margin-bottom: 32px; }
.hero .btn + .btn { margin-left: 16px; }
.hero-meta { margin-top: 24px; font-size: 14px; color: var(--text-light); }

/* ===== 区块通用 ===== */
.section { padding: 64px 0; }
.section-gray { background: var(--bg-gray); }
.section-title { text-align: center; font-size: 30px; margin-bottom: 12px; }
.section-desc { text-align: center; color: var(--text-light); margin-bottom: 48px; }

/* ===== 网格卡片 ===== */
.grid { display: grid; gap: 24px; }
.grid-3 { grid-template-columns: repeat(3, 1fr); }
.grid-4 { grid-template-columns: repeat(4, 1fr); }
.card {
  background: var(--bg); border: 1px solid var(--border);
  border-radius: var(--radius); padding: 28px 24px;
  transition: 0.2s;
}
.card:hover { box-shadow: 0 8px 24px rgba(37, 99, 235, 0.1); transform: translateY(-4px); }
.card h3 { font-size: 18px; margin-bottom: 10px; }
.card p { font-size: 14px; color: var(--text-light); }
.card-icon { font-size: 32px; margin-bottom: 14px; }

/* ===== 数据条 ===== */
.stats { display: flex; justify-content: center; gap: 64px; text-align: center; }
.stats strong { display: block; font-size: 32px; color: var(--primary); }
.stats span { font-size: 14px; color: var(--text-light); }

/* ===== 下载页版本卡片 ===== */
.download-card {
  display: flex; align-items: center; justify-content: space-between;
  background: var(--bg); border: 1px solid var(--border);
  border-radius: var(--radius); padding: 28px 32px; margin-bottom: 20px;
}
.download-card h3 { font-size: 18px; margin-bottom: 6px; }
.download-card .info { font-size: 13px; color: var(--text-light); }

/* ===== 教程步骤 ===== */
.step { display: flex; gap: 20px; margin-bottom: 32px; }
.step-num {
  flex-shrink: 0; width: 44px; height: 44px; border-radius: 50%;
  background: var(--primary); color: #fff; font-size: 20px; font-weight: 700;
  display: flex; align-items: center; justify-content: center;
}
.step h3 { font-size: 18px; margin-bottom: 8px; }
.step p { color: var(--text-light); font-size: 15px; }

/* ===== FAQ 折叠 ===== */
.faq-item { border-bottom: 1px solid var(--border); }
.faq-question {
  width: 100%; background: none; border: none; text-align: left;
  font-size: 16px; font-weight: 600; padding: 20px 0; cursor: pointer;
  display: flex; justify-content: space-between; align-items: center;
  color: var(--text);
}
.faq-question::after { content: "+"; font-size: 20px; color: var(--primary); }
.faq-question.open::after { content: "-"; }
.faq-answer { display: none; padding-bottom: 20px; color: var(--text-light); font-size: 15px; }
.faq-answer.open { display: block; }

/* ===== 页脚 ===== */
.footer { background: #111827; color: #9ca3af; padding: 48px 0 24px; margin-top: 64px; }
.footer-grid { display: grid; grid-template-columns: 2fr 1fr 1fr; gap: 32px; margin-bottom: 32px; }
.footer h4 { color: #fff; font-size: 16px; margin-bottom: 14px; }
.footer a { display: block; font-size: 14px; margin-bottom: 8px; }
.footer a:hover { color: #fff; }
.footer-bottom { border-top: 1px solid #374151; padding-top: 20px; text-align: center; font-size: 13px; }

/* ===== 响应式 ===== */
@media (max-width: 860px) {
  .grid-3, .grid-4 { grid-template-columns: 1fr 1fr; }
  .footer-grid { grid-template-columns: 1fr; }
  .nav {
    display: none; position: absolute; top: 64px; left: 0; right: 0;
    background: var(--bg); flex-direction: column; padding: 16px 5%;
    border-bottom: 1px solid var(--border);
  }
  .nav.show { display: flex; }
  .nav-toggle { display: block; }
  .hero h1 { font-size: 28px; }
  .stats { gap: 32px; flex-wrap: wrap; }
}
@media (max-width: 560px) {
  .grid-3, .grid-4 { grid-template-columns: 1fr; }
  .download-card { flex-direction: column; text-align: center; gap: 16px; }
}