/* ===== 主题变量：改这里即可整体换肤 ===== */
:root {
  --accent: #4f6ef7;
  --accent-dark: #3a55d9;
  --ink: #1c2333;
  --ink-soft: #5a6377;
  --bg: #ffffff;
  --bg-alt: #f6f8fc;
  --line: #e6eaf2;
  --radius: 12px;
  --shadow: 0 8px 30px rgba(28, 35, 51, 0.08);
}

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

html { scroll-behavior: smooth; }

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

a { color: var(--accent); text-decoration: none; }
a:hover { color: var(--accent-dark); }

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

.container {
  width: min(1080px, 100% - 48px);
  margin-inline: auto;
}

/* ===== 顶部导航 ===== */
.site-header {
  position: sticky;
  top: 0;
  z-index: 100;
  background: rgba(255, 255, 255, 0.85);
  backdrop-filter: blur(10px);
  border-bottom: 1px solid var(--line);
}

.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 64px;
}

.logo {
  display: flex;
  align-items: center;
  gap: 8px;
  font-weight: 700;
  font-size: 1.2rem;
  color: var(--ink);
}

.logo-mark {
  display: grid;
  place-items: center;
  width: 32px;
  height: 32px;
  border-radius: 8px;
  background: var(--accent);
  color: #fff;
  font-size: 1.1rem;
}

.site-nav { display: flex; gap: 28px; }

.site-nav a {
  color: var(--ink-soft);
  font-size: 0.95rem;
  transition: color 0.2s;
}

.site-nav a:hover,
.site-nav a.active { color: var(--accent); }

/* 移动端菜单按钮（默认隐藏） */
.nav-toggle {
  display: none;
  flex-direction: column;
  gap: 5px;
  border: none;
  background: none;
  cursor: pointer;
  padding: 6px;
}

.nav-toggle span {
  width: 22px;
  height: 2px;
  background: var(--ink);
  border-radius: 2px;
  transition: transform 0.25s, opacity 0.25s;
}

.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 首屏 ===== */
.hero {
  background:
    radial-gradient(1000px 400px at 80% -10%, rgba(79, 110, 247, 0.14), transparent),
    radial-gradient(800px 400px at 10% 110%, rgba(79, 110, 247, 0.08), transparent),
    var(--bg-alt);
  border-bottom: 1px solid var(--line);
}

.hero-inner {
  padding: 110px 0 120px;
  text-align: center;
}

.hero h1 {
  font-size: clamp(2rem, 5vw, 3rem);
  letter-spacing: 0.02em;
}

.hero-sub {
  margin: 18px auto 0;
  max-width: 560px;
  color: var(--ink-soft);
  font-size: 1.1rem;
}

.hero-actions {
  margin-top: 36px;
  display: flex;
  justify-content: center;
  gap: 16px;
  flex-wrap: wrap;
}

/* ===== 按钮 ===== */
.btn {
  display: inline-block;
  padding: 12px 28px;
  border-radius: 999px;
  font-size: 0.95rem;
  font-weight: 600;
  transition: background 0.2s, color 0.2s, border-color 0.2s;
}

.btn-primary {
  background: var(--accent);
  color: #fff;
}

.btn-primary:hover { background: var(--accent-dark); color: #fff; }

.btn-ghost {
  border: 1px solid var(--line);
  color: var(--ink);
  background: #fff;
}

.btn-ghost:hover { border-color: var(--accent); color: var(--accent); }

/* ===== 通用小节 ===== */
.section { padding: 90px 0; }
.section-alt { background: var(--bg-alt); border-block: 1px solid var(--line); }

.section-title {
  font-size: 1.8rem;
  text-align: center;
  margin-bottom: 12px;
}

.section-desc {
  text-align: center;
  color: var(--ink-soft);
  margin-bottom: 48px;
}

/* ===== 服务卡片 ===== */
.cards {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(230px, 1fr));
  gap: 24px;
}

.card {
  background: #fff;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 28px;
  box-shadow: var(--shadow);
  transition: transform 0.2s;
}

.card:hover { transform: translateY(-4px); }

.card-icon { font-size: 1.8rem; margin-bottom: 12px; }

.card h3 { font-size: 1.1rem; margin-bottom: 8px; }

.card p { color: var(--ink-soft); font-size: 0.95rem; }

/* ===== 关于我们 ===== */
.about-inner { max-width: 760px; text-align: center; }

.about-inner p { color: var(--ink-soft); margin-bottom: 16px; }

.about-stats {
  list-style: none;
  display: flex;
  justify-content: center;
  gap: 56px;
  margin-top: 40px;
  flex-wrap: wrap;
}

.about-stats li { display: flex; flex-direction: column; }

.about-stats strong { font-size: 1.8rem; color: var(--accent); }

.about-stats span { color: var(--ink-soft); font-size: 0.9rem; }

/* ===== 联系方式 ===== */
.contact-list {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
  gap: 24px;
  max-width: 720px;
  margin: 0 auto;
}

.contact-item {
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 24px;
  text-align: center;
}

.contact-label {
  display: block;
  color: var(--ink-soft);
  font-size: 0.9rem;
  margin-bottom: 6px;
}

/* ===== 页脚 ===== */
.site-footer {
  border-top: 1px solid var(--line);
  padding: 32px 0;
  text-align: center;
  color: var(--ink-soft);
  font-size: 0.9rem;
}

.site-footer a { color: inherit; }
.site-footer a:hover { color: var(--accent); }

.site-footer p + p { margin-top: 6px; }

/* ===== 滚动进入动画（配合 main.js） ===== */
.reveal {
  opacity: 0;
  transform: translateY(16px);
  transition: opacity 0.5s ease, transform 0.5s ease;
}

.reveal.visible { opacity: 1; transform: none; }

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  .reveal { opacity: 1; transform: none; transition: none; }
}

/* ===== 响应式 ===== */
@media (max-width: 720px) {
  .nav-toggle { display: flex; }

  .site-nav {
    position: absolute;
    top: 64px;
    left: 0;
    right: 0;
    flex-direction: column;
    gap: 0;
    background: #fff;
    border-bottom: 1px solid var(--line);
    max-height: 0;
    overflow: hidden;
    transition: max-height 0.3s ease;
  }

  .site-nav.open { max-height: 300px; }

  .site-nav a {
    padding: 14px 24px;
    border-top: 1px solid var(--line);
  }

  .hero-inner { padding: 72px 0 84px; }

  .section { padding: 64px 0; }

  .about-stats { gap: 32px; }
}