/* 顶部导航右侧：音乐播放/关闭按钮 */

.r-nav-c .btn_music {
	display: block;
	width: 40px;
	height: 40px;
	margin: 0 auto;
	background: url(../image/btn_music_on.png) no-repeat center center;
	background-size: 100% 100%;
	cursor: pointer;
	border: 0;
	outline: none;
	transition: filter .2s ease;
}

.r-nav-c .btn_music:hover {
	filter: brightness(1.18);
}

/* 暂停/关闭状态：换成灰色关闭图标 */
.r-nav-c .btn_music.is-paused {
	background-image: url(../image/btn_music_off.png);
}

/* 播放中：图标缓慢旋转 */
.r-nav-c .btn_music.is-playing {
	animation: musicSpin 5s linear infinite;
}

@keyframes musicSpin {
	from { transform: rotate(0deg); }
	to   { transform: rotate(360deg); }
}