/* 资讯中心：兆易式 hover 下拉（父级为按钮，不可跳转） */

.nav-item-mega {
  position: relative;
}

.nav-mega-trigger {
  appearance: none;
  border: none;
  background: none;
  cursor: pointer;
  font: inherit;
  color: var(--text-primary);
  font-size: 16px;
  font-weight: 500;
  padding: 0;
  position: relative;
  display: inline-flex;
  align-items: center;
  gap: 0;
  transition: color 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

.nav-mega-trigger:hover,
.nav-item-mega:hover .nav-mega-trigger,
.nav-mega-trigger:focus-visible {
  color: var(--primary-color);
}

.nav-mega-trigger.active {
  color: var(--primary-color);
}

.nav-mega-trigger::after {
  content: '';
  position: absolute;
  bottom: -4px;
  left: 0;
  width: 0;
  height: 2px;
  background-color: var(--primary-color);
  transition: width 0.3s ease;
}

.nav-mega-trigger:hover::after,
.nav-mega-trigger.active::after,
.nav-item-mega:hover .nav-mega-trigger::after {
  width: 100%;
}

/* 使用 100vw + inset，避免任意祖先带 transform 时 fixed 仍相对错误参照导致无法拉满 */
.nav-mega-panel {
  position: fixed;
  top: 76px;
  left: 0;
  width: 100vw;
  max-width: 100vw;
  right: auto;
  margin: 0;
  box-sizing: border-box;
  z-index: 1001;
  background: #fff;
  border-bottom: 1px solid var(--border-color);
  box-shadow: 0 16px 48px rgba(15, 23, 42, 0.08);
  opacity: 0;
  visibility: hidden;
  pointer-events: none;
  transform: translateY(-8px);
  transition: opacity 0.22s ease, visibility 0.22s ease, transform 0.22s ease;
}

/* 在触发项下方补一条窄衔接区，减轻导航栏与面板之间的垂直缝隙（不全宽，避免挡住其它主导航链接） */
.nav-mega-panel::before {
  content: '';
  position: absolute;
  left: 50%;
  transform: translateX(-50%);
  width: min(280px, 70vw);
  top: -14px;
  height: 14px;
  background: transparent;
}

.nav-mega-inner {
  max-width: 1120px;
  margin: 0 auto;
  padding: 36px 40px 44px;
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 48px;
}

.nav-mega-col-title {
  font-size: 14px;
  font-weight: 600;
  letter-spacing: 0.03em;
  color: var(--text-secondary);
  text-transform: none;
  margin: 0 0 18px;
  padding-bottom: 14px;
  border-bottom: 1px solid var(--border-color);
}

.nav-mega-links {
  list-style: none;
  margin: 0;
  padding: 0;
}

.nav-mega-links li {
  margin: 0 0 8px;
}

.nav-mega-links a {
  display: block;
  padding: 8px 0;
  color: var(--text-primary);
  text-decoration: none;
  font-size: 15px;
  font-weight: 500;
  line-height: 1.45;
  border-radius: 6px;
  margin: 0 -8px;
  padding-left: 8px;
  padding-right: 8px;
  transition: background 0.15s ease, color 0.15s ease;
}

.nav-mega-links a:hover {
  background: rgba(37, 99, 235, 0.06);
  color: var(--primary-color);
}

@media (min-width: 769px) {
  .nav-menu .nav-item-mega {
    align-self: stretch;
    display: flex;
    align-items: center;
  }

  .nav-item-mega:hover .nav-mega-panel,
  .nav-item-mega:focus-within .nav-mega-panel,
  .nav-item-mega.nav-item-mega--open .nav-mega-panel {
    opacity: 1;
    visibility: visible;
    pointer-events: auto;
    transform: translateY(0);
  }

  /* 抵消侧栏祖先位移时 left:0 相对视口偏移（双保险） */
  .nav-mega-panel {
    left: 50%;
    margin-left: -50vw;
  }
}

@media (max-width: 768px) {
  .nav-mega-panel {
    position: static;
    opacity: 1;
    visibility: visible;
    transform: none;
    pointer-events: auto;
    display: none;
    border: none;
    box-shadow: none;
    background: transparent;
    top: auto;
    z-index: auto;
    left: auto;
    margin-left: 0;
    width: auto;
    max-width: none;
  }

  .nav-item-mega.is-open .nav-mega-panel {
    display: block;
  }

  .nav-mega-inner {
    grid-template-columns: 1fr;
    gap: 28px;
    padding: 16px 0 8px 12px;
    margin-top: 8px;
    border-left: 2px solid var(--border-color);
  }

  .nav-mega-trigger::after {
    display: none;
  }

  .nav-item-mega {
    width: 100%;
    text-align: left;
  }

  .nav-mega-trigger {
    width: 100%;
    justify-content: space-between;
  }
}