html,
body {
  scroll-behavior: smooth;
  margin: 0;
  font-family: "PingFang SC", "Microsoft YaHei", sans-serif;
  overflow-x: hidden;
}
#logo_top {
  font-size: 28px;
  font-weight: bold;
  color: #011128;
}
header {
  position: fixed;
  top: 0;
  width: 100%;
  z-index: 1000;
  background: rgba(255, 255, 255, 0.95);
  box-shadow: 0 2px 8px rgba(0, 0, 0, 0.05);
  transition: all 0.3s;
}

.header-container {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 10px 40px;
  max-width: 100%;
  margin: auto;
}

.nav-left a {
  font-weight: bold;
  font-size: 22px;
  color: #333;
  text-decoration: none;
}

.nav-mid ul {
  display: flex;
  gap: 40px;
  list-style: none;
  margin: 0;
  padding: 0;
}

.nav-mid ul li a {
  text-decoration: none;
  font-size: 16px;
  color: #333;
  transition: color 0.3s;
}

.nav-mid ul li a:hover,
.nav-mid ul li a.active {
  color: #ff6600;
}

/* 手机端菜单按钮 */
.menu-toggle {
  display: none;
  flex-direction: column;
  cursor: pointer;
  gap: 5px;
}

.menu-toggle span {
  width: 25px;
  height: 3px;
  background: #333;
  border-radius: 2px;
}

@media (max-width: 768px) {
  .nav-mid {
    display: none;
    position: absolute;
    top: 60px;
    right: 0;
    background: white;
    width: 100%;
    box-shadow: 0 4px 10px rgba(0, 0, 0, 0.1);
  }

  .nav-mid.active {
    display: block;
  }

  .nav-mid ul {
    flex-direction: column;
    align-items: center;
    gap: 20px;
    padding: 20px 0;
  }

  .menu-toggle {
    display: flex;
  }
}

/* 页面通用 */
section {
  position: relative;
  width: 100%;
  display: flex;
  justify-content: center;
  align-items: center;
  overflow: hidden;
}

section img.bg {
  width: 100%;
  height: 100%;
  object-fit: contain;
}

footer {
  background: #111;
  color: #aaa;
  text-align: center;
  padding: 20px 0;
  font-size: 14px;
}

.back-to-top {
  position: fixed;
  right: 30px;
  bottom: 30px;
  width: 50px;
  height: 50px;
  border: none;
  border-radius: 50%;
  background-color: #ff6600;
  color: white;
  font-size: 24px;
  display: none;
  justify-content: center;
  align-items: center;
  cursor: pointer;
  transition: all 0.3s;
  z-index: 1001;
}

.back-to-top:hover {
  background-color: #e05500;
}

/* 联系我们模块 */
#contact {
  position: relative;
  background: #011128;
  color: #fff;
  text-align: center;
  padding: 80px 20px 10px;
}

#contact::before {
  content: "";
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  opacity: 0.35;
  z-index: 0;
}

.contact-content {
  position: relative;
  z-index: 1;
  max-width: 800px;
  margin: 0 auto;
}

.contact-content h2 {
  font-size: 40px;
  margin-bottom: 30px;
  font-weight: 600;
}

.contact-content p {
  margin: 10px 0;
  font-size: 18px;
  line-height: 1.8;
}

.contact-content .copyright {
  font-size: 14px;
  color: #ccc;
  margin-top: 30px;
}