/* ============================================ */
/* 公共样式文件 - 所有页面共享的基础样式          */
/* 天楚科技 品牌系统                             */
/* ============================================ */

html {
  scroll-behavior: smooth;
}

/* ---------- 全局重置 ---------- */
*, *::before, *::after {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", sans-serif;
  color: #1e293b;
  background: #ffffff;
  line-height: 1.6;
}

a {
  text-decoration: none;
  color: inherit;
}

ul {
  list-style: none;
}

/* ---------- 导航栏 ---------- */
.navbar {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  height: 64px;
  background: rgba(15, 23, 42, 0.95);
  backdrop-filter: blur(8px);
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0 48px;
  z-index: 1000;
  transition: background 0.3s;
}

.navbar .logo {
  font-size: 20px;
  font-weight: 700;
  color: #ffffff;
  letter-spacing: 1px;
}

.navbar .logo span {
  color: #3b82f6;
}

/* 导航链接列表 */
.nav-links {
  display: flex;
  align-items: center;
  gap: 32px;
  margin: 0;
}

.nav-links > li {
  position: relative;
  list-style: none;
}

.nav-links > li > a {
  color: #94a3b8;
  font-size: 14px;
  transition: color 0.2s;
  position: relative;
  padding: 8px 0;
  cursor: pointer;
  display: inline-block;
}

.nav-links > li > a:hover,
.nav-links > li > a.active {
  color: #ffffff;
}

.nav-links > li > a .arrow {
  font-size: 10px;
  margin-left: 4px;
  color: inherit;
}

/* 导航链接底部下划线动画 */
.nav-links > li > a::after {
  content: "";
  position: absolute;
  bottom: -4px;
  left: 0;
  width: 0%;
  height: 2px;
  background: #3b82f6;
  transition: width 0.3s;
}

.nav-links > li > a:hover::after,
.nav-links > li > a.active::after {
  width: 100%;
}

/* 下拉菜单（桌面端） */
.dropdown-menu {
  display: none;
  position: absolute;
  top: 100%;
  left: 50%;
  transform: translateX(-50%);
  background: rgba(15, 23, 42, 0.98);
  backdrop-filter: blur(8px);
  border-radius: 0 0 8px 8px;
  padding: 8px 0;
  min-width: 150px;
  box-shadow: 0 8px 24px rgba(0, 0, 0, 0.35);
  z-index: 1001;
  border-top: 2px solid #3b82f6;
}

.nav-links > li:hover > .dropdown-menu {
  display: block;
}

.dropdown-menu li {
  list-style: none;
}

.dropdown-menu li a {
  display: block;
  padding: 10px 24px;
  color: #94a3b8;
  font-size: 14px;
  white-space: nowrap;
  transition: color 0.2s, background 0.2s;
}

.dropdown-menu li a:hover {
  color: #ffffff;
  background: rgba(59, 130, 246, 0.12);
}

.dropdown-menu li a::after {
  display: none !important;
}

/* 页面主体内容区（为固定导航栏留出空间） */
main {
  margin-top: 64px;
}

/* ---------- 通用容器 ---------- */
.container {
  max-width: 1100px;
  margin: 0 auto;
}

section {
  padding: 80px 48px;
}

/* ---------- 页脚 ---------- */
footer {
  background: #0f172a;
  color: #94a3b8;
  text-align: center;
  padding: 32px 48px;
  font-size: 14px;
}

footer a {
  color: #3b82f6;
}

/* ---------- 渐入动画 ---------- */
.fade-in {
  opacity: 0;
  transform: translateY(24px);
  transition: opacity 0.6s ease, transform 0.6s ease;
}

.fade-in.visible {
  opacity: 1;
  transform: translateY(0);
}

/* ---------- 移动端菜单按钮 ---------- */
.mobile-menu-btn {
  display: none;
  background: none;
  border: none;
  color: #ffffff;
  font-size: 24px;
  cursor: pointer;
  padding: 4px;
  line-height: 1;
}

/* ---------- 响应式布局 ---------- */
@media (max-width: 768px) {
  .navbar {
    padding: 0 20px;
  }

  /* 移动端主导航菜单：从导航栏上方落下 */
  .nav-links {
    display: flex;
    position: fixed;
    z-index: 999;
    top: 64px;
    left: 0;
    right: 0;
    max-height: 80vh;
    background: rgba(15, 23, 42, 0.98);
    flex-direction: column;
    padding: 16px 20px;
    gap: 8px;
    box-shadow: 0 8px 24px rgba(0, 0, 0, 0.35);
    transform: translateX(110%);
    transition: transform 0.35s cubic-bezier(0.4, 0, 0.2, 1), visibility 0.35s;
    visibility: hidden;
    overflow-y: auto;
  }

  .nav-links.open {
    transform: translateX(0);
    visibility: visible;
  }

  .nav-links > li {
    position: static;
  }

  .nav-links > li > a {
    padding: 12px 0;
    font-size: 15px;
    width: 100%;
    display: block;
  }

  .nav-links > li > a::after {
    display: none;
  }

  /* 移动端下拉菜单：max-height 滑入滑出动画 */
  .dropdown-menu {
    position: static;
    background: rgba(59, 130, 246, 0.05);
    border-radius: 0;
    box-shadow: none;
    transform: none;
    display: block;
    max-height: 0;
    overflow: hidden;
    opacity: 0;
    padding-top: 0;
    padding-bottom: 0;
    margin-left: 8px;
    border-left: 2px solid transparent;
    transition: max-height 0.35s ease, opacity 0.25s ease, padding 0.35s ease, border-left-color 0.35s ease;
  }

  .dropdown-menu.open {
    max-height: 400px;
    opacity: 1;
    padding-top: 8px;
    padding-bottom: 8px;
    border-left-color: rgba(59, 130, 246, 0.4);
  }

  /* 移动端禁用 hover 展开，仅使用点击切换；:not(.open) 确保 .open 永远不被 hover 覆盖 */
  .nav-links > li:hover > .dropdown-menu:not(.open) {
    max-height: 0;
    opacity: 0;
  }

  .dropdown-menu li a {
    padding: 10px 16px;
    font-size: 14px;
  }

  .mobile-menu-btn {
    display: block;
  }

  section {
    padding: 48px 20px;
  }
}

@media (max-width: 480px) {
  section {
    padding: 32px 16px;
  }
}