/**
 * 全站基础样式：变量、重置、顶栏导航、返回顶部
 * 与 nav-shared.css、footer.css 配合使用；放在 font-awesome 之后、页面内联样式之前
 */

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

:root {
  --primary-color: #0066cc;
  --secondary-color: #00a896;
  --accent-color: #ff6b6b;
  --light-color: #f8f9fa;
  --dark-color: #343a40;
  --gray-color: #6c757d;
  --light-gray: #e9ecef;
  --border-radius: 8px;
  --box-shadow: 0 4px 12px rgba(0, 0, 0, 0.1);
  --transition: all 0.3s ease;
}

body {
  font-family: "Microsoft YaHei", Arial, sans-serif;
  line-height: 1.6;
  color: #333;
  background-color: #f5f7fa;
}

.quick-links a {
  color: #ccc;
  text-decoration: none;
  margin-left: 15px;
  transition: var(--transition);
}

.quick-links a:hover {
  color: white;
}

/* 导航栏 */
.navbar {
  background-color: white;
  box-shadow: 0 2px 15px rgba(0, 0, 0, 0.1);
  position: sticky;
  top: 0;
  z-index: 1000;
}

.nav-container {
  max-width: 1400px;
  margin: 0 auto;
  display: flex;
  padding: 0 30px;
  align-items: center;
}

.logo {
  display: flex;
  align-items: center;
  padding: 10px 0;
}

.logo img {
  height: 50px;
}

.logo-text {
  margin-left: 10px;
  font-size: 18px;
  font-weight: bold;
  color: var(--primary-color);
}

.nav-menu {
  display: flex;
  list-style: none;
  margin-left: auto;
}

.nav-menu li {
  position: relative;
}

.nav-menu > li > a {
  display: block;
  color: var(--dark-color);
  text-decoration: none;
  padding: 25px 40px;
  font-size: 16px;
  font-weight: 500;
  transition: var(--transition);
  margin: 0 2px;
}

.nav-menu > li > a:hover {
  color: var(--primary-color);
}

.nav-menu > li > a.active {
  color: var(--primary-color);
}

.nav-menu ul {
  position: absolute;
  top: 100%;
  left: 0;
  background-color: white;
  box-shadow: 0 8px 16px rgba(0, 0, 0, 0.1);
  border-radius: var(--border-radius);
  list-style: none;
  padding: 8px 0;
  min-width: 220px;
  opacity: 0;
  visibility: hidden;
  transform: translateY(10px);
  transition: all 0.3s ease;
  z-index: 1001;
}

.nav-menu > li:hover > ul {
  opacity: 1;
  visibility: visible;
  transform: translateY(0);
}

.nav-menu ul li {
  width: 100%;
}

.nav-menu ul li a {
  display: block;
  padding: 4px 12px;
  color: var(--dark-color);
  text-decoration: none;
  font-size: 14px;
  transition: all 0.3s ease;
  text-align: center;
}

.nav-menu ul li a:hover {
  background-color: var(--primary-color);
  color: white;
  padding-left: 15px;
}

.nav-menu > li > a::after {
  content: " ";
  font-size: 10px;
  margin-left: 5px;
  vertical-align: middle;
  transition: transform 0.3s ease;
}

.nav-menu > li:hover > a::after {
  transform: rotate(180deg);
}

.nav-menu > li:nth-child(1) > a::after {
  content: "";
}

/* 返回顶部 */
.back-to-top {
  position: fixed;
  bottom: 30px;
  right: 30px;
  width: 50px;
  height: 50px;
  background-color: var(--primary-color);
  color: white;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  opacity: 0;
  visibility: hidden;
  transform: translateY(20px);
  transition: var(--transition);
  z-index: 1000;
  box-shadow: 0 4px 12px rgba(0, 0, 0, 0.15);
}

.back-to-top.show {
  opacity: 1;
  visibility: visible;
  transform: translateY(0);
}

.back-to-top:hover {
  background-color: var(--secondary-color);
  transform: translateY(-3px);
}