.jumbotron-index {
    background: url('../img/index/jumbotron-background.jpg') no-repeat center center;
    background-size: cover;
}

.jumbotron-index .display-4 {
    color: #ffffff;
}
.jumbotron-index .lead {
    color: #ffffff;
}

.display-4 {
    font-size: 2.5rem;
}

.index-content-block {
    margin-top: 5rem;
}
.index-content-block:first-of-type {
    margin-top: 3rem;
}
.index-content-block .title {
    text-align: center;
    background: url(../img/index/cat-bg.png) center no-repeat;
    font-size: 2.3rem;
}
.index-content-block .title > .red{
    color: #db171f;
}
.index-content-block .content {
    margin-top: 2rem;
}
.index-content-block .lead {
    text-align: center;
}
.index-content-block p {
    line-height: 1.6rem;
}
.index-content-block a {
    color: #343a40;
}
.index-content-block a:hover {
    color:#dc3545;
}
/* 自定义样式，改变选中 tab 的颜色 */
.nav-tabs .nav-link.active {
  color: #D30505; /* 红色 */
}