.bd-placeholder-img {
    font-size: 1.125rem;
    text-anchor: middle;
    -webkit-user-select: none;
    -moz-user-select: none;
    user-select: none;
}


.bi {
    vertical-align: -.125em;
    fill: currentColor;
}

/* 给导航栏设置背景颜色 */
.navbar {
    display: flex;
    justify-content: center;
}

/* 给导航栏中的链接设置颜色 */
.navbar a {
    color: #f2f2f2;
    padding: 14px 16px;
    text-decoration: none;
    border-radius: 4px;
    border: 1px solid transparent;
}

/* 鼠标移动到链接上时的效果 */
.navbar a:hover {
    background-color: #ddd;
    color: black;
}

/* 选中的标签的样式 */
.navbar a.active {
    background-color: #f3c120;
    color: white;
}


.icon-link > .bi {
    margin-top: .125rem;
    margin-left: .125rem;
    fill: currentcolor;
    transition: transform .25s ease-in-out;
}

.icon-link:hover > .bi {
    transform: translate(.25rem);
}


.text-shadow-1 {
    text-shadow: 0 .125rem .25rem rgba(0, 0, 0, .25);
}


.card-cover {
    background-repeat: no-repeat;
    background-position: center center;
    background-size: cover;
}