/* Find at least 3 ways to fix the margin collapsing problem. */


.wrap {
    max-width: 600px;
    margin: 0 auto;
    background: orange;
    margin-top: 200px;
}

.box {
    width: 100%;
    height: 200px;
    background: slateblue;
   
}
  

/* #1 */
.w1 {

}
.w1 .box {

}


/* #2 */
.w2 {
 
}
.w2 .box {
    
}


/* #3 */
.w3 {
 
}
.w3 .box {
  
}