Element Selector - Selects elements based on tag name
p { color: blue; } /* selects all <p> elements */
div { margin: 10px; } /* selects all <div> elements */Class Selector - Selects elements with specific class
.container { width: 80%; } /* selects elements with class="container" */
.btn-primary { background-color: #007bff; } /* selects elements with class="btn-primary" */ID Selector - Selects element with specific ID
#header { position: fixed; } /* selects element with id="header" */
#main-content { padding: 20px; } /* selects element with id="main-content" */Universal Selector - Selects all elements
* { box-sizing: border-box; } /* applies to all elements */