.arrow_box {
position: relative;
background: #f0f0f0;
border: 4px solid #f0f0f0;
}
.arrow_box:after, .arrow_box:before {
bottom: 94%;
left: 2%;
border: solid transparent;
content: " ";
height: 0;
width: 0;
position: absolute;
pointer-events: none;
}
.arrow_box:after {
border-color: rgba(240, 240, 240, 0);
border-bottom-color: #f0f0f0;
border-width: 10px;
margin-left: -10px;
}
.arrow_box:before {
border-color: rgba(240, 240, 240, 0);
border-bottom-color: #f0f0f0;
border-width: 16px;
margin-left: -16px;
}