Question

Is it possible to make rounding like the dark area on the image below with pure CSS?

Answer 1

Absolutely. Just create a DIV, and attach a class with rules like these:

.rounded_box {
    width: 90px;
    height: 60px;
    border-top-left-radius: 11px 30px;
    border-bottom-left-radius: 11px 30px;
    background-color: #333333;
}

<div class="rounded_box"></div>

Depending upon the browser support you’re looking for, you may need to add some additional vendor-specific prefixes for the border-radius lines. Such as:

-webkit-border-top-left-radius: 11px 30px;
-webkit-border-bottom-left-radius: 11px 30px;
-moz-border-radius-topleft: 11px 30px;
-moz-border-radius-bottomleft: 11px 30px;