/* ============================================================
 * 智帮咨询 V4 · 导航栏样式（全站统一）
 * 版本：V4.0
 * 加载顺序：tokens.css → base.css → v4-upgrade.css → nav.css
 * 说明：本文件是导航栏的单一真相源，所有页面共用
 * ============================================================ */

/* ===== 导航专属配色（不随页面 accent 变化，全站统一）===== */
:root {
  --nav-accent:        #C8642A;
  --nav-accent-hover:  #B0551F;
  --nav-accent-light:  rgba(200,100,42,.08);
  --nav-accent-rgb:    200, 100, 42;
}

/* ===== 导航容器 ===== */
nav.site-nav {
  position: sticky;
  top: 0;
  left: 0;
  width: 100%;
  background: rgba(255,255,255,.93);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border-soft);
  z-index: var(--z-nav);
  transition: box-shadow var(--duration-base);
}
nav.site-nav.scrolled {
  box-shadow: 0 1px 4px rgba(0,0,0,.06);
}

/* ===== 汉堡开关（隐藏 checkbox）===== */
.nav-toggle-input { display: none; }

/* ===== 导航内部布局 ===== */
.nav-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 64px;
}

/* ===== Logo ===== */
.nav-logo {
  display: flex;
  align-items: center;
  gap: 10px;
  color: var(--text-title);
  font-family: var(--font-heading);
  font-weight: 800;
  font-size: var(--fs-lg);
  letter-spacing: 1px;
}
.nav-logo img {
  width: 32px;
  height: 32px;
  flex-shrink: 0;
  display: block;
  background: transparent;
  border: 0;
  box-shadow: none;
  object-fit: contain;
}

/* ===== 桌面端链接 ===== */
.nav-links {
  display: flex;
  align-items: center;
  gap: var(--space-md);
}
.nav-links > a,
.nav-item-dropdown > a {
  color: var(--text-body);
  font-size: var(--fs-sm);
  font-weight: 600;
  padding: 8px 4px;
  transition: color var(--duration-fast);
}
.nav-links > a:hover,
.nav-links > a.active,
.nav-item-dropdown > a:hover,
.nav-item-dropdown > a.active,
.nav-item-dropdown.is-open > a {
  color: var(--nav-accent);
}

/* ===== 下拉菜单 ===== */
.nav-item-dropdown { position: relative; }
.nav-item-dropdown > a {
  display: inline-flex;
  align-items: center;
  gap: 4px;
  cursor: pointer;
}
.nav-item-dropdown .arrow {
  font-size: 10px;
  transition: transform var(--duration-base);
}
.nav-item-dropdown.is-open .arrow {
  transform: rotate(180deg);
}
.nav-dropdown-menu {
  position: absolute;
  top: 100%;
  left: 50%;
  transform: translateX(-50%);
  background: var(--white);
  border: 1px solid var(--border-soft);
  border-radius: var(--radius-md);
  box-shadow: 0 8px 24px rgba(0,0,0,.08);
  min-width: 220px;
  padding: 8px 0;
  opacity: 0;
  visibility: hidden;
  transition: all var(--duration-base) var(--ease-out);
  margin-top: 8px;
  z-index: var(--z-dropdown);
}
.nav-dropdown-menu::before {
  content: '';
  position: absolute;
  top: -6px;
  left: 50%;
  transform: translateX(-50%) rotate(45deg);
  width: 12px;
  height: 12px;
  background: var(--white);
}
.nav-item-dropdown.is-open .nav-dropdown-menu {
  opacity: 1;
  visibility: visible;
  margin-top: 0;
}
.nav-dropdown-menu a {
  display: flex;
  align-items: center;
  gap: 8px;
  padding: 10px 18px;
  font-size: var(--fs-sm);
  color: var(--text);
  font-weight: 500;
}
.nav-dropdown-menu a:hover {
  background: var(--nav-accent-light);
  color: var(--nav-accent);
}
.nav-dropdown-menu .dot {
  width: 6px;
  height: 6px;
  border-radius: 50%;
  background: var(--nav-accent);
  flex-shrink: 0;
}
.nav-dropdown-menu .hot-badge {
  font-size: 10px;
  padding: 2px 7px;
  border-radius: 3px;
  background: var(--nav-accent);
  color: var(--white);
  margin-left: auto;
  font-weight: 700;
  letter-spacing: .5px;
}

/* ===== CTA 按钮 ===== */
.nav-cta {
  padding: 8px 20px;
  background: var(--nav-accent);
  color: var(--white) !important;
  border-radius: var(--radius-sm);
  font-size: var(--fs-sm);
  font-weight: 700;
  transition: background var(--duration-fast);
}
.nav-cta:hover {
  background: var(--nav-accent-hover);
  color: var(--white) !important;
}

/* ===== 搜索图标 ===== */
.nav-search {
  display: flex;
  align-items: center;
  color: var(--text-body);
  padding: 8px 6px;
  transition: color var(--duration-fast);
}
.nav-search:hover,
.nav-search.active {
  color: var(--nav-accent);
}

/* ===== 移动端汉堡按钮 ===== */
.nav-toggle-label {
  display: none;
  width: 28px;
  height: 22px;
  flex-direction: column;
  justify-content: space-between;
  cursor: pointer;
}
.nav-toggle-label span {
  display: block;
  height: 2.5px;
  width: 100%;
  background: var(--text-title);
  border-radius: 2px;
  transition: all var(--duration-base) var(--ease-out);
}

/* ===== 移动端展开面板 ===== */
.nav-mobile {
  display: none;
  position: absolute;
  top: 100%;
  left: 0;
  width: 100%;
  background: rgba(255,255,255,.98);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  overflow: hidden;
  max-height: 0;
  transition: max-height var(--duration-slow) var(--ease-out);
}
.nav-mobile-inner {
  padding: var(--space-md);
}
.nav-mobile-links {
  display: flex;
  flex-direction: column;
  gap: 4px;
}
.nav-mobile-links a {
  padding: 12px 16px;
  color: var(--text-body);
  border-radius: var(--radius-sm);
  font-size: var(--fs-base);
  font-weight: 500;
}
.nav-mobile-links a:hover,
.nav-mobile-links a.active {
  background: var(--nav-accent-light);
  color: var(--nav-accent);
}
.nav-mobile-cta {
  display: block;
  margin-top: var(--space-md);
  padding: 14px 16px;
  background: var(--nav-accent);
  color: var(--white);
  border-radius: var(--radius-md);
  text-align: center;
  font-weight: 700;
}

/* ===== 汉堡菜单交互（checkbox hack）===== */
#navToggle:checked ~ .nav-mobile {
  max-height: 600px;
}
#navToggle:checked + .container .nav-toggle-label span:nth-child(1) {
  transform: translateY(10px) rotate(45deg);
}
#navToggle:checked + .container .nav-toggle-label span:nth-child(2) {
  opacity: 0;
}
#navToggle:checked + .container .nav-toggle-label span:nth-child(3) {
  transform: translateY(-10px) rotate(-45deg);
}

/* ===== 移动端搜索链接（在 nav-mobile-links 外部）===== */
.nav-mobile-search {
  display: block;
  padding: 12px 16px;
  color: var(--text-body);
  font-size: var(--fs-base);
  font-weight: 500;
}
.nav-mobile-search:hover {
  color: var(--nav-accent);
}

/* ===== 响应式 ===== */
@media (max-width: 768px) {
  .nav-links { display: none; }
  .nav-toggle-label { display: flex; }
  .nav-mobile { display: block; }
}