Gradient rouded border with opacity

gradiend_round_opacity_border.css

/*
<div class="control-wrapper">
    <div class="control-wrapper__opacity"></div>
    <a href="javascript:void(0);" class="control simple-btn clear-btn">Очистить матрицы</a>
</div>
*/

.control-wrapper {
    padding: 1px;
    border-radius: 3px;
    position: relative;
}

.control-wrapper__opacity {
    width: 100%;
    height: 100%;
    top: 0;
    left: 0;
    position: absolute;
    opacity: 0.5;
    border-radius: 3px;
    background: linear-gradient(to bottom, #d9d9d9, #b2b2b2);
}

.control {
    font-family: 'Segoe', Arial, sans-serif;
    font-size: 14px;
    color: #404040;
    text-decoration: none;
}

.simple-btn {
    display: block;
    padding: 8px 9px;
    cursor: pointer;
    opacity: 1;
    background: linear-gradient(to bottom, #fefefe, #ececec);
    border-radius: 3px;
    position:relative;
    z-index: 2;
}