Cascading Style Sheets（CSS）を使用して角の丸いアイコンを実装します。

ご自由にご利用ください。

Previews

Examples html

<!-- icons -->

<div class="icons">

	<button class="item" type="button" aria-label="play"></button>

</div>

<!-- /icons -->

Examples css

/* - icons - */

.icons {
	position: relative;
	width: 25px;
	height: 25px;
	margin: 0px 0px 0px 0px;
	padding: 0px 0px 0px 0px;
	background-color: rgba(0, 0, 0, 0.0);
	border: 2px solid rgba(0, 0, 0, 1.0);
	-webkit-border-radius: 50%;
	border-radius: 50%;
	transition: all .5s;
	cursor: pointer;
}

.icons button.item {
	display: block;
	position: absolute;
	top: 6px;
	left: 6.5px;
	width: 6px;
	height: 6px;
	margin: 0px 0px 0px 0px;
	padding: 0px 0px 0px 0px;
	background-color: rgba(0, 0, 0, 1.0);
	-webkit-border-top-left-radius: 25%;
	border-top-left-radius: 25%;
	-webkit-transform: rotate(0deg) skewY(30deg) scaleX(.86666);
	transform: rotate(0deg) skewY(30deg) scaleX(.86666);
	transition: all .5s;
}

.icons button.item::before {
	content: "";
	display: block;
	position: absolute;
	top: 0px;
	left: 0px;
	width: 6px;
	height: 6px;
	margin: 0px 0px 0px 0px;
	padding: 0px 0px 0px 0px;
	background-color: rgba(0, 0, 0, 1.0);
	-webkit-border-top-right-radius: 25%;
	border-top-right-radius: 25%;
	-webkit-transform: skewX(-45deg) translateX(50%);
	transform: skewX(-45deg) translateX(50%);
	transition: all .5s;
}

.icons button.item::after {
	content: "";
	display: block;
	position: absolute;
	top: 0px;
	left: 0px;
	width: 6px;
	height: 6px;
	margin: 0px 0px 0px 0px;
	padding: 0px 0px 0px 0px;
	background-color: rgba(0, 0, 0, 1.0);
	-webkit-border-bottom-left-radius: 25%;
	border-bottom-left-radius: 25%;
	-webkit-transform: skewY(-45deg) translateY(50%);
	transform: skewY(-45deg) translateY(50%);
	transition: all .5s;
}

.icons:hover {
	border: 2px solid rgba(192, 192, 192, 1.0);
}

.icons:hover button.item,
.icons:hover button.item::before,
.icons:hover button.item::after {
	background-color: rgba(192, 192, 192, 1.0);
}

.icons:active {
	border: 2px solid rgba(0, 0, 0, 1.0);
}

.icons:active button.item,
.icons:active button.item::before,
.icons:active button.item::after {
	background-color: rgba(0, 0, 0, 1.0);
}

/* - /icons - */