CSS選擇器是用于在HTML文檔中定位和選擇元素的一種方式。CSS提供了多種選擇器，包括：

1. 類選擇器（Class Selector）：使用.符號，例如.classname。
2. ID選擇器（ID Selector）：使用#符號，例如#idname。
3. 標簽選擇器（Tag Selector）：使用<tag>和</tag>之間的內(nèi)容，例如<div>或<p>。
4. 屬性選擇器（Attribute Selector）：使用[attribute]，例如[]。
5. 后代選擇器（Descendant Selector）：使用>符號，例如>div。
6. 相鄰兄弟選擇器（Adjacent Sibling Selector）：使用+符號，例如+div。
7. 子集選擇器（Child Combinators）：使用~符號，例如~div。
8. 偽類選擇器（Pseudo-Class Selector）：使用:hover, :active, :visited, :link, :focus, :checked, :enabled, :in-the-background, :not()等。
9. 偽元素選擇器（Pseudo-Element Selector）：使用::before, ::after, ::first-child, ::last-child, ::only-child, ::empty, ::first-of-type, ::last-of-type, ::only-of-type, ::only-instance, ::only-child, ::only-descendant, ::only-sibling, ::only-ancestor, ::only-grandparent, ::only-parent, ::only-child-of-type, ::only-child-of-ancestor, ::only-child-of-parent, ::only-child-of-parent-of-type, ::only-child-of-parent-of-ancestor, ::only-child-of-parent-of-parent, ::only-child-of-parent-of-parent-of-type, ::only-child-of-parent-of-parent-of-ancestor, ::only-child-of-parent-of-parent-of-parent, ::only-child-of-parent-of-parent-of-parent-of-type, ::only-child-of-parent-of-parent-of-parent-of-ancestor, ::only-child-of-parent-of-parent-of-parent-of-parent, ::only-child-of-parent-of-parent-of-parent-of-parent-of-type, ::only-child-of-parent-of-parent-of-parent-of-parent-of-ancestor, ::only-child-of-parent-of-parent-of-parent-of-parent-of-parent, ::only-child-of-parent-of-parent-of-parent-of-parent-of-parent-of-type, ::only-child-of-parent-of-parent-of-parent-of-parent-of-parent, ::only-child-of-parent-of-parent-of-parent-of-parent-of-parent-of-type, ::only-child-of-parent-of-parent-of-parent-of-parent-of-parent, ::only-child-of-parent-of-parent-of-parent-of-parent-of-parent-of-type, ::only-child-of-parent-of-parent-of-parent-of-parent-of-parent, ::only-child-of-parent-of-parent-of-parent-of-parent-of-parent-of-type, ::only-child-of-parent-of-parent-of-parent-of-parent-of-parent, ::only-child-of-parent-of-parent-of-parent-of-parent-of-parent, ::only-child-of-parent-of-parent-of-parent-of-parent, ::only-child-of-parent-of-parent, ::only-child, ::only-element, ::first, ::last, ::first-child, ::last-child, ::only-child, ::only-element, ::first, ::last, ::first-child, ::last-child, ::only-child, ::only-element, ::first, ::last, ::first-child, ::last-child, ::only-child, ::only-element, ::first, ::last, ::first-child, ::last-child, ::only-child, ::only-element, ::first, ::last, ::first-child, ::last-child, ::only-child, ::only-element, ::first, ::last, ::first-child, ::last-child, ::only-child, ::only-element, ::first, ::last, ::first-child, ::last-child, ::only-child, ::only-element, ::first, ::last, ::first-child, ::last-child, ::only-child, ::only-element, ::first, ::last, ::first-child, ::last-child, ::only-child, ::only-element, ::first, ::last, ::first-child, ::last-child, ::only-child, ::only-element, ::first, ::last, ::first-child, ::last-child, ::only-child, ::only-element, ::first, ::last, ::first-child, ::last-child, ::only-child, ::only-element, ::first, ::last, ::first-child, ::last-child, ::only-child, ::only-element, ::first, ::last, ::first-child, ::last-child, ::only-child, ::only-element, ::first, ::last, ::first-child, ::last-child, ::only-child, ::only-element, ::first, ::last, ::first-child, ::last-child, ::only-child, ::only-element, ::first, ::last, ::first-child, ::last-child, ::only-child, ::only-element, ::first, ::last, ::first-child, ::last-child, ::only-child, ::only-element, ::first, ::last, ::first-child, ::last-child, ::only-child, ::only-element, ::first, ::last, ::first-child, ::last-child, ::only-child, ::only-element, ::first, ::last, ::first-child, ::last-child, ::only-child, ::only-element, ::first, ::last, ::first-child, `::last-child},

這些選擇器之間的區(qū)別主要在于它們匹配的元素類型、位置和上下文。以下是一些常見的區(qū)別：

1. 類選擇器（Class Selector）與ID選擇器（ID Selector）的區(qū)別：

   1. 類選擇器基于元素的類名進行匹配，而ID選擇器基于元素的ID進行匹配。
   2. 類選擇器可以應用于多個具有相同類名的元素，而ID選擇器只能應用于一個特定的元素。

2. 標簽選擇器（Tag Selector）與屬性選擇器（Attribute Selector）的區(qū)別：

   1. 標簽選擇器基于元素的標簽名進行匹配，而屬性選擇器基于元素的某個屬性值進行匹配。
   2. 標簽選擇器可以應用于所有具有特定標簽名的元素，而屬性選擇器只能應用于具有特定屬性值的元素。

3. 后代選擇器（Descendant Selector）與相鄰兄弟選擇器（Adjacent Sibling Selector）的區(qū)別：

   1. 后代選擇器基于元素的直接后代進行匹配，而相鄰兄弟選擇器基于元素的直接相鄰兄弟進行匹配。
   2. 后代選擇器可以應用于所有具有特定后代元素的元素，而相鄰兄弟選擇器只能應用于具有特定相鄰兄弟元素的元素。

4. 子集選擇器（Child Combinators）與偽類選擇器（Pseudo-Class Selector）的區(qū)別：

   1. 子集選擇器基于元素的子集進行匹配，而偽類選擇器基于元素的某種狀態(tài)進行匹配。
   2. 子集選擇器可以應用于所有具有特定子集元素的元素，而偽類選擇器只能應用于具有特定狀態(tài)元素的元素。

5. 偽元素選擇器（Pseudo-Element Selector）與偽類選擇器（Pseudo-Class Selector）的區(qū)別：

   1. 偽元素選擇器基于元素的偽元素進行匹配，而偽類選擇器基于元素的某種狀態(tài)進行匹配。
   2. 偽元素選擇器可以應用于所有具有特定偽元素元素的元素，而偽類選擇器只能應用于具有特定狀態(tài)元素的元素。

6. 通用選擇器（Universal Selector）與特定選擇器（Specific Selector）的區(qū)別：

   1. 通用選擇器可以應用于任何元素，而特定選擇器只能應用于具有特定類名、ID、標簽名、屬性值、后代、相鄰兄弟、子集、偽元素或偽類的元素。

這些選擇器可以根據(jù)需要進行組合，以實現(xiàn)更復雜的CSS樣式應用。