/* ============================================================
   照片恢复卫士 官网样式表
   策略：移动优先（Mobile First）+ 响应式断点
   断点：默认 = 手机；≥768px = 平板；≥1024px = PC
   ============================================================ */

/* ===== 1. 基础重置 ===== */
*,*::before,*::after { box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; -webkit-tap-highlight-color: transparent; scroll-behavior: smooth; }
body {
  margin: 0;
  font-family: -apple-system, BlinkMacSystemFont, "PingFang SC", "Microsoft YaHei", "Helvetica Neue", Helvetica, Arial, sans-serif;
  font-size: 16px;
  line-height: 1.7;
  color: #1f2328;
  background: #fff;
  -webkit-font-smoothing: antialiased;
  word-wrap: break-word;
}
img { max-width: 100%; height: auto; display: block; }
a { color: #1f6feb; text-decoration: none; }
a:hover { color: #0a58ca; }
ul { padding: 0; margin: 0; list-style: none; }
button { font-family: inherit; cursor: pointer; }
h1,h2,h3,h4 { margin: 0 0 .5em; line-height: 1.3; font-weight: 700; }
h1 { font-size: 1.6rem; }
h2 { font-size: 1.4rem; }
h3 { font-size: 1.15rem; }

.container { width: 100%; max-width: 1200px; margin: 0 auto; padding: 0 16px; }

/* ===== 2. 顶部导航（移动优先） ===== */
.site-header {
  position: sticky; top: 0; z-index: 100;
  background: rgba(255,255,255,.96);
  backdrop-filter: saturate(180%) blur(8px);
  border-bottom: 1px solid #eaeef2;
}
.nav-bar {
  display: flex; align-items: center; justify-content: space-between;
  height: 56px;
}
.logo img { height: 32px; width: auto; }

/* 汉堡按钮（手机） */
.nav-toggle {
  width: 40px; height: 40px; border: 0; background: transparent;
  display: flex; flex-direction: column; justify-content: center; gap: 5px; padding: 0;
}
.nav-toggle span {
  display: block; width: 22px; height: 2px; background: #1f2328; border-radius: 2px;
  transition: transform .25s, opacity .2s;
}
.nav-toggle.is-open span:nth-child(1) { transform: translateY(7px) rotate(45deg); }
.nav-toggle.is-open span:nth-child(2) { opacity: 0; }
.nav-toggle.is-open span:nth-child(3) { transform: translateY(-7px) rotate(-45deg); }

/* 移动端抽屉菜单 */
.nav-menu {
  position: fixed; top: 56px; left: 0; right: 0;
  background: #fff; border-top: 1px solid #eaeef2;
  max-height: 0; overflow: hidden; transition: max-height .3s ease;
}
.nav-menu.is-open { max-height: 100vh; overflow-y: auto; }
.nav-menu > ul { padding: 8px 16px 24px; }
.nav-menu > ul > li { border-bottom: 1px solid #f1f3f5; }
.nav-menu a { display: block; padding: 14px 4px; color: #1f2328; font-size: 1rem; }
.nav-menu .sub-menu { padding-left: 16px; }
.nav-menu .sub-menu a { padding: 10px 4px; color: #57606a; font-size: .95rem; }
.nav-menu .lang-switch { display: flex; align-items: center; gap: 8px; padding: 12px 4px; }
.nav-menu .lang-switch a { padding: 0; display: inline; }
.nav-menu .lang-switch .active { color: #1f6feb; font-weight: 600; }
.nav-menu .btn-cta {
  display: inline-block; margin-top: 10px;
  background: #1f6feb; color: #fff !important; border-radius: 6px;
  padding: 10px 18px !important; text-align: center; font-weight: 600;
}

/* ===== 3. Hero ===== */
.hero {
  background: linear-gradient(180deg,#f6faff 0%,#eef4ff 100%);
  padding: 32px 0 40px;
}
.hero-inner { display: grid; gap: 24px; }
.hero h1 { font-size: 1.6rem; line-height: 1.35; }
.hero-sub { color: #57606a; font-size: 1rem; margin: 12px 0 16px; }
.hero-points { margin: 16px 0 20px; }
.hero-points li {
  padding: 6px 0; font-size: .95rem; color: #24292f;
}
.hero-cta { display: flex; flex-wrap: wrap; gap: 12px; margin-bottom: 14px; }
.hero-trust { font-size: .85rem; color: #6e7781; }
.hero-img img { border-radius: 12px; box-shadow: 0 12px 32px rgba(31,111,235,.12); }

/* 按钮 */
.btn {
  display: inline-block; min-width: 140px; padding: 12px 22px;
  border-radius: 8px; text-align: center; font-weight: 600; font-size: 1rem;
  transition: transform .15s, box-shadow .2s;
  border: 1px solid transparent;
}
.btn:hover { transform: translateY(-1px); }
.btn-primary { background: #1f6feb; color: #fff; }
.btn-primary:hover { background: #1158c7; color: #fff; box-shadow: 0 6px 18px rgba(31,111,235,.32); }
.btn-secondary { background: #fff; color: #1f6feb; border-color: #1f6feb; }
.btn-secondary:hover { background: #f0f6ff; color: #0a58ca; }

/* ===== 4. 区块通用 ===== */
.section-title { text-align: center; font-size: 1.5rem; margin: 0 0 8px; }
.section-sub { text-align: center; color: #6e7781; margin: 0 0 24px; font-size: .95rem; }

.features { padding: 48px 0; background: #fff; }
.feature-grid { display: grid; grid-template-columns: 1fr; gap: 16px; }
.feature-card {
  display: block; padding: 22px 20px; border-radius: 12px;
  background: #f6f8fa; border: 1px solid #eaeef2;
  color: #1f2328;
  transition: transform .2s, box-shadow .25s, border-color .2s;
}
.feature-card:hover {
  transform: translateY(-3px);
  box-shadow: 0 12px 28px rgba(31,111,235,.08);
  border-color: #1f6feb33;
  color: #1f2328;
}
.feature-icon { font-size: 2rem; line-height: 1; margin-bottom: 10px; }
.feature-card h3 { margin: 0 0 8px; font-size: 1.1rem; }
.feature-card p { margin: 0 0 12px; color: #57606a; font-size: .92rem; }
.feature-link { color: #1f6feb; font-weight: 600; font-size: .9rem; }

/* ===== 5. 场景区 ===== */
.scenes { padding: 48px 0; background: #f6f8fa; }
.scene-grid { display: grid; grid-template-columns: 1fr; gap: 14px; }
.scene-item {
  background: #fff; padding: 20px; border-radius: 10px; border: 1px solid #eaeef2;
}
.scene-item h3 { font-size: 1.05rem; margin: 0 0 6px; color: #1f6feb; }
.scene-item p { margin: 0; color: #57606a; font-size: .92rem; }

/* ===== 6. FAQ ===== */
.faq { padding: 48px 0; background: #fff; }
.faq-item {
  background: #f6f8fa; border: 1px solid #eaeef2;
  border-radius: 10px; padding: 14px 18px; margin-bottom: 12px;
}
.faq-item summary {
  cursor: pointer; font-weight: 600; font-size: 1rem;
  list-style: none; outline: none; position: relative;
  padding-right: 28px;
}
.faq-item summary::-webkit-details-marker { display: none; }
.faq-item summary::after {
  content: "+"; position: absolute; right: 4px; top: 50%; transform: translateY(-50%);
  font-size: 1.4rem; color: #1f6feb; transition: transform .2s;
}
.faq-item[open] summary::after { content: "−"; }
.faq-item p { margin: 12px 0 0; color: #57606a; line-height: 1.75; }

/* ===== 7. CTA Band ===== */
.cta-band {
  background: linear-gradient(135deg,#1f6feb 0%,#0a58ca 100%);
  color: #fff; padding: 48px 0; text-align: center;
}
.cta-band h2 { color: #fff; font-size: 1.4rem; margin-bottom: 24px; }
.cta-band .btn-primary { background: #fff; color: #1f6feb; }
.cta-band .btn-primary:hover { background: #f0f6ff; color: #0a58ca; }
.cta-band .btn-secondary { background: transparent; color: #fff; border-color: #fff; }
.cta-band .btn-secondary:hover { background: rgba(255,255,255,.1); color: #fff; }
.cta-buttons { display: flex; justify-content: center; flex-wrap: wrap; gap: 12px; }

/* ===== 8. Footer ===== */
.site-footer { background: #0d1117; color: #8b949e; padding-top: 40px; }
.footer-grid {
  display: grid; grid-template-columns: 1fr; gap: 28px; padding-bottom: 28px;
}
.footer-col h4 { color: #fff; font-size: 1rem; margin-bottom: 12px; }
.footer-col img { filter: brightness(0) invert(1); opacity: .9; margin-bottom: 12px; }
.footer-col p { color: #8b949e; font-size: .9rem; line-height: 1.7; }
.footer-col ul li { padding: 4px 0; }
.footer-col a { color: #8b949e; font-size: .9rem; }
.footer-col a:hover { color: #fff; }
.footer-legal {
  border-top: 1px solid #21262d; padding: 18px 0;
  font-size: .8rem; color: #6e7781;
}
.footer-legal p { margin: 4px 0; }
.footer-legal a { color: #8b949e; }
.footer-legal a:hover { color: #fff; }

/* ============================================================
   响应式断点
   ============================================================ */

/* ====== ≥768px: 平板 ====== */
@media (min-width: 768px) {
  body { font-size: 16px; }
  h1 { font-size: 2rem; }
  h2 { font-size: 1.6rem; }

  .hero { padding: 56px 0 64px; }
  .hero h1 { font-size: 2.2rem; }
  .hero-sub { font-size: 1.1rem; }

  .feature-grid { grid-template-columns: repeat(2, 1fr); gap: 20px; }
  .scene-grid { grid-template-columns: repeat(2, 1fr); gap: 18px; }
  .footer-grid { grid-template-columns: repeat(2, 1fr); gap: 32px; }

  .section-title { font-size: 1.8rem; }
}

/* ====== ≥1024px: PC ====== */
@media (min-width: 1024px) {
  .nav-toggle { display: none; }
  .nav-menu {
    position: static; max-height: none; overflow: visible;
    background: transparent; border: 0;
  }
  .nav-menu > ul {
    display: flex; align-items: center; gap: 4px;
    padding: 0;
  }
  .nav-menu > ul > li { border: 0; position: relative; }
  .nav-menu > ul > li > a {
    padding: 8px 14px; border-radius: 6px; font-size: .95rem;
  }
  .nav-menu > ul > li > a:hover { background: #f6f8fa; color: #1f6feb; }

  /* PC 下拉子菜单 */
  .nav-menu .has-sub:hover .sub-menu,
  .nav-menu .has-sub:focus-within .sub-menu { display: block; }
  .nav-menu .sub-menu {
    display: none; position: absolute; top: 100%; left: 0;
    min-width: 200px; background: #fff;
    border: 1px solid #eaeef2; border-radius: 8px;
    box-shadow: 0 12px 32px rgba(0,0,0,.08);
    padding: 6px 0;
  }
  .nav-menu .sub-menu a { padding: 8px 16px; font-size: .92rem; }
  .nav-menu .sub-menu a:hover { background: #f6f8fa; color: #1f6feb; }

  .nav-menu .lang-switch { padding: 0 12px; }
  .nav-menu .btn-cta {
    margin: 0 0 0 8px; padding: 8px 18px !important; border-radius: 6px;
  }

  .hero-inner { grid-template-columns: 1.1fr 1fr; align-items: center; gap: 48px; }
  .hero h1 { font-size: 2.6rem; }

  .feature-grid { grid-template-columns: repeat(3, 1fr); gap: 24px; }
  .scene-grid { grid-template-columns: repeat(3, 1fr); gap: 20px; }
  .footer-grid { grid-template-columns: 1.4fr 1fr 1fr 1fr; gap: 40px; }

  .features, .scenes, .faq, .cta-band { padding: 72px 0; }

  .section-title { font-size: 2rem; }

  .faq-item { padding: 18px 24px; }
  .faq-item summary { font-size: 1.05rem; }
}

/* ====== ≥1440px: 大屏 ====== */
@media (min-width: 1440px) {
  .container { padding: 0 24px; }
  .hero h1 { font-size: 2.8rem; }
}

/* ====== 暗黑模式（可选，自动跟随系统） ====== */
@media (prefers-color-scheme: dark) {
  /* 国内 SEO 主要看亮色，暗色仅作访客体验，不影响 SEO */
  /* 如需启用，取消下面注释 */
  /*
  body { background: #0d1117; color: #c9d1d9; }
  .site-header { background: rgba(13,17,23,.96); border-color: #21262d; }
  */
}

/* ====== 减少动画偏好 ====== */
@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after { animation-duration: .01ms !important; transition-duration: .01ms !important; scroll-behavior: auto !important; }
}

/* ====== 打印 ====== */
@media print {
  .site-header, .nav-toggle, .cta-band, .site-footer { display: none; }
}