/**************** Button top return  BEGIN *************/
/* 返回顶部按钮样式 */
#backToTop {
    position: fixed;
    bottom: 30px;
    right: 30px;
    width: 70px;
    height: 70px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    z-index: 1000;
    /* box-shadow: 0 4px 6px rgba(0, 0, 0, 0.1); */
    border: 0px;
    display: none;
    /* 默认隐藏按钮 */
}

/* 外层圆形 */
.outer-circle {
    position: absolute;
    width: 96%;
    height: 96%;
    border-radius: 50%;
    background-color: #d3e4fc;
    border: none;
}

/* 中层圆形 */
.middle-circle {
    position: absolute;
    width: 92%;
    height: 92%;
    border-radius: 50%;
    background-color: #fffae4;
    border: none;
    z-index: 1;
}

/* 内层圆形 */
.inner-circle {
    position: absolute;
    width: 86%;
    height: 86%;
    top: 50%;
    transform: translateY(-50%);
    background: url(https://static.igem.wiki/teams/5872/home-matl/back-to-top2.svg) no-repeat;
    background-size: 126%;
    background-position: center center;
    border-radius: 50%;
    border: none;
    z-index: 2;
}

.inner-circle span {
    position: absolute;
    top: -34px;
    right: 20px;
    font-family: 'icomoon';
    font-size: 40px;
    font-weight: 700;
    /* color: #4e659c; */
    border: none;
    z-index: -2;
}

/* 中间圆形的进度条 */
.progress-bar {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    border-radius: 50%;
    border: none;
    /* background: conic-gradient(#055007 0%, #b9e9ba 50%, orange 100%); */
    z-index: 0;
}