How To Use Css Triangle With After Pseudo Element And Lower Z-index?

I have already tried almost all solutions in Stack Overflow related to this issue. I have below CSS code. .logo { background-image: url('../Images/Brookland-Splash- MOBILE_0000s

Solution 1:

Just use position: relative in .logo div

.logo {
     background-image: url("../Images/Brookland-Splash-
     MOBILE_0000s_0000s_0001_BrooklandPress-CMYK-copy-2.png");
     width:124px;
     height: 131px;
     float: left;
     margin-left: 290px;
     margin-top: 30px;
     margin-bottom: 93px;
     z-index: 10;
     position: relative
 }
.logo::after {
     content: '';
     border-left: 80px solid transparent;
     border-right: 80px solid transparent;
     border-top: 80px solid white;
     position: absolute;
     width: 0;
     height: 0;
     top: 120px;
     left: 275px;
     clear: both;
}