/**
 * 侧边栏手风琴式菜单样式
 * 支持流畅的展开/收起动画效果
 */

/* 菜单组容器 */
.nav-group {
  margin-bottom: 0.8rem;
  border-radius: 8px;
  overflow: hidden;
  background: rgba(255, 255, 255, 0.05);
  backdrop-filter: blur(4px);
  transition: all 0.3s ease;
}

.nav-group:hover {
  background: rgba(255, 255, 255, 0.1);
  box-shadow: 0 2px 8px rgba(250, 140, 50, 0.1);
}

/* 组标题样式 */
.group-header.collapsible {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 12px 16px;
  cursor: pointer;
  user-select: none;
  border-radius: 8px;
  transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
  background: linear-gradient(135deg, rgba(250, 140, 50, 0.1), rgba(255, 221, 0, 0.05));
  border: 1px solid rgba(250, 140, 50, 0.2);
  position: relative;
  overflow: hidden;
}

.group-header.collapsible::before {
  content: '';
  position: absolute;
  top: 0;
  left: -100%;
  width: 100%;
  height: 100%;
  background: linear-gradient(90deg, transparent, rgba(250, 140, 50, 0.1), transparent);
  transition: left 0.5s ease;
}

.group-header.collapsible:hover::before {
  left: 100%;
}

.group-header.collapsible:hover {
  background: linear-gradient(135deg, rgba(250, 140, 50, 0.15), rgba(255, 221, 0, 0.08));
  border-color: rgba(250, 140, 50, 0.3);
  transform: translateX(2px);
  box-shadow: 0 4px 12px rgba(250, 140, 50, 0.2);
}

.group-header.collapsible:active {
  transform: translateX(1px) scale(0.98);
  box-shadow: 0 2px 8px rgba(250, 140, 50, 0.15);
}

/* 组标题文字 */
.group-title {
  font-size: 1rem;
  font-weight: 600;
  color: #333;
  letter-spacing: 0.5px;
  text-shadow: 0 1px 2px rgba(255, 255, 255, 0.5);
  transition: color 0.3s ease;
}

.group-header.collapsible:hover .group-title {
  color: #fa8c32;
}

/* 切换图标样式 */
.toggle-icon {
  font-size: 0.9rem;
  color: #666;
  transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
  font-weight: bold;
  width: 20px;
  height: 20px;
  display: flex;
  align-items: center;
  justify-content: center;
  border-radius: 50%;
  background: rgba(255, 255, 255, 0.3);
  border: 1px solid rgba(250, 140, 50, 0.2);
  /* 默认隐藏，防止页面加载时闪现 */
  opacity: 0;
  visibility: hidden;
}

/* JavaScript初始化完成后显示图标 */
.sidebar-accordion-initialized .toggle-icon {
  opacity: 1;
  visibility: visible;
}

.group-header.collapsible:hover .toggle-icon {
  color: #fa8c32;
  background: rgba(250, 140, 50, 0.1);
  border-color: rgba(250, 140, 50, 0.3);
  box-shadow: 0 2px 6px rgba(250, 140, 50, 0.2);
}

.toggle-icon.expanded {
  transform: rotate(90deg);
  color: #fa8c32;
  background: rgba(250, 140, 50, 0.15);
  border-color: rgba(250, 140, 50, 0.4);
  box-shadow: 0 2px 8px rgba(250, 140, 50, 0.25);
}

/* 子菜单容器 */
.sub-list {
  padding-left: 0;
  margin-top: 0;
  max-height: 0;
  overflow: hidden;
  transition: all 0.4s cubic-bezier(0.4, 0, 0.2, 1);
  background: linear-gradient(135deg, rgba(255, 255, 255, 0.08), rgba(250, 140, 50, 0.02));
  border-top: 1px solid rgba(250, 140, 50, 0.1);
  opacity: 0;
  transform: translateY(-10px);
}

.sub-list.collapsed {
  max-height: 0;
  margin-top: 0;
  opacity: 0;
  transform: translateY(-10px);
  padding-top: 0;
  padding-bottom: 0;
}

.sub-list.expanded {
  max-height: 500px;
  opacity: 1;
  transform: translateY(0);
  padding-top: 8px;
  padding-bottom: 8px;
}

.sub-list.expanding {
  opacity: 0.7;
  transform: translateY(-5px);
}

.sub-list.collapsing {
  opacity: 0.3;
  transform: translateY(-5px);
}

/* 子菜单项样式 */
.sub-list li {
  margin-bottom: 0.3rem;
  padding: 0 16px;
  opacity: 0;
  transform: translateX(-10px);
  transition: all 0.3s ease;
  transition-delay: calc(var(--item-index, 0) * 0.05s);
}

.sub-list.expanded li {
  opacity: 1;
  transform: translateX(0);
}

.sub-list li:nth-child(1) { --item-index: 1; }
.sub-list li:nth-child(2) { --item-index: 2; }
.sub-list li:nth-child(3) { --item-index: 3; }
.sub-list li:nth-child(4) { --item-index: 4; }
.sub-list li:nth-child(5) { --item-index: 5; }
.sub-list li:nth-child(6) { --item-index: 6; }

/* 子菜单链接样式 */
.sub-list a {
  color: #555;
  font-size: 0.9rem;
  font-weight: 400;
  padding: 8px 12px;
  border-radius: 6px;
  transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
  position: relative;
  display: block;
  text-decoration: none;
  border-left: 3px solid transparent;
}

.sub-list a::before {
  content: '';
  position: absolute;
  left: 0;
  top: 0;
  width: 0;
  height: 100%;
  background: linear-gradient(90deg, rgba(250, 140, 50, 0.1), rgba(250, 140, 50, 0.05));
  transition: width 0.3s ease;
  border-radius: 0 6px 6px 0;
}

.sub-list a:hover::before {
  width: 100%;
}

.sub-list a:hover {
  color: #fa8c32;
  background: rgba(250, 140, 50, 0.08);
  transform: translateX(4px);
  border-left-color: #fa8c32;
  box-shadow: 0 2px 8px rgba(250, 140, 50, 0.15);
}

.sub-list a:active {
  transform: translateX(2px) scale(0.98);
}

/* 嵌套子菜单 (三级菜单) */
.sub-list .sub-list {
  margin-left: 16px;
  margin-top: 4px;
  padding-left: 8px;
  border-left: 2px dashed rgba(250, 140, 50, 0.3);
  background: rgba(255, 255, 255, 0.05);
  border-radius: 0 4px 4px 0;
  max-height: none;
  opacity: 1;
  transform: translateY(0);
  transition: all 0.3s ease;
}

.sub-list.collapsed .sub-list {
  max-height: 0;
  opacity: 0;
  transform: translateY(-5px);
  margin-top: 0;
  overflow: hidden;
}

.sub-list.expanded .sub-list {
  max-height: none;
  opacity: 1;
  transform: translateY(0);
  margin-top: 4px;
}

.sub-list .sub-list li {
  margin-bottom: 0.2rem;
  padding: 0 8px;
}

.sub-list .sub-list a {
  font-size: 0.8rem;
  color: #777;
  padding: 4px 8px;
  border-radius: 4px;
  border-left: 2px solid transparent;
  transition: all 0.2s ease;
}

.sub-list .sub-list a:hover {
  color: #fa8c32;
  background: rgba(250, 140, 50, 0.08);
  border-left-color: #fa8c32;
  transform: translateX(2px);
}

.sub-list .sub-list a::before {
  content: '•';
  color: rgba(250, 140, 50, 0.6);
  margin-right: 6px;
  font-size: 0.7rem;
}

/* 焦点样式 */
.group-header.collapsible:focus {
  outline: 2px solid rgba(250, 140, 50, 0.5);
  outline-offset: 2px;
  box-shadow: 0 0 0 4px rgba(250, 140, 50, 0.1);
}

.sub-list a:focus {
  outline: 2px solid rgba(250, 140, 50, 0.5);
  outline-offset: 1px;
  background: rgba(250, 140, 50, 0.08);
}

/* 移动端优化 */
@media (max-width: 768px) {
  .nav-group {
    margin-bottom: 0.6rem;
  }
  
  .group-header.collapsible {
    padding: 10px 12px;
    border-radius: 6px;
  }
  
  .group-title {
    font-size: 0.95rem;
  }
  
  .toggle-icon {
    font-size: 0.8rem;
    width: 18px;
    height: 18px;
  }
  
  .sub-list li {
    padding: 0 12px;
    margin-bottom: 0.2rem;
  }
  
  .sub-list a {
    font-size: 0.85rem;
    padding: 6px 10px;
  }
  
  .sub-list .sub-list {
    margin-left: 15px;
  }
}

/* 超小屏优化 */
@media (max-width: 480px) {
  .group-header.collapsible {
    padding: 8px 10px;
  }
  
  .group-title {
    font-size: 0.9rem;
  }
  
  .sub-list li {
    padding: 0 10px;
  }
  
  .sub-list a {
    font-size: 0.8rem;
    padding: 5px 8px;
  }
}

/* 高对比度主题支持 */
@media (prefers-contrast: high) {
  .group-header.collapsible {
    border-color: #fa8c32;
    background: rgba(250, 140, 50, 0.2);
  }
  
  .group-title {
    color: #000;
    font-weight: 700;
  }
  
  .toggle-icon {
    color: #fa8c32;
    border-color: #fa8c32;
  }
  
  .sub-list a {
    color: #333;
    border-left-width: 4px;
  }
  
  .sub-list a:hover {
    background: rgba(250, 140, 50, 0.15);
    border-left-color: #fa8c32;
  }
}

/* 减少动画模式 */
@media (prefers-reduced-motion: reduce) {
  .group-header.collapsible,
  .toggle-icon,
  .sub-list,
  .sub-list li,
  .sub-list a {
    transition: none;
  }
  
  .group-header.collapsible::before {
    display: none;
  }
}