css - Bootstrap 4垂直对齐div的中心和底部

Question

我使用 Bootstrap 4。.top block 应该是 100% 宽度和全屏高度。 .top-title 应位于屏幕中间。 .btn-scroll-down 应位于屏幕下方。

我希望我的页面看起来像

HTML

<!-- top -->
        <div class="top js-top">
            <div class="container h-100">
                <div class="row h-100">

                    <div class="col-lg-12">
                        <h1 class="top-title">
                            <span class="top-title-1">text</span>
                            <span class="top-title-2">title</span>
                            <span class="top-title-3">text</span>
                        </h1>
                        <a href="" class="btn-redirect link-go-to-match">go</a>

                        <a href="#" class="btn-scroll-down js-btn-scroll-down"></a>
                    </div>
                </div>
            </div>
        </div>  
    <!-- /top -->

CSS

.btn-redirect {
    display: block;
    width: 301px;
    height: 57px;
    margin: 0;
    padding: 20px 0;
    cursor: pointer;
    -webkit-transition: background-color .3s linear;
    -moz-transition: background-color .3s linear;
    -ms-transition: background-color .3s linear;
    -o-transition: background-color .3s linear;
    text-align: center;
    text-transform: uppercase;
    color: #fff;
    border-radius: 10px;
    background-color: #ff780c;
    background-clip: padding-box;
}

.btn-scroll-down {
    position: absolute;
    bottom: 2%;
    left: 50%;
    display: block;
    width: 54px;
    height: 54px;
    margin-left: -27px;
    content: '';
    -webkit-transition: opacity .3s;
    -moz-transition: opacity .3s;
    -ms-transition: opacity .3s;
    -o-transition: opacity .3s;
    opacity: .5;
    border: 3px solid #fff;
    border-radius: 50%;
    background-clip: padding-box;
}

.top
{
    overflow: hidden;
    height: 100%;
    height: 100vh;
    min-height: 100%;
    min-height: 100vh;
    background-image: url(../images/bg_main.jpg);
    background-repeat: no-repeat;
    background-position: 50% 50%;
    background-size: cover;
    background-color: red;
}
.top .top-title
{
    padding-top: 35vh;
    text-align: center;
    text-transform: uppercase;
    color: #fff;
}
.top .top-title .top-title-1
{
    font-family: 'RobotoRegular';
    font-size: 3vh;
    display: block;
}
.top .top-title .top-title-2
{
    font-family: 'DaysOneRegular';
    font-size: 15vh;
    line-height: 1;
    display: block;
    margin-top: 2vh;
}
.top .top-title .top-title-3
{
    font-family: 'RobotoRegular';
    font-size: 3vh;
    display: block;
    margin-top: 2vh;
}
.top .link-go-to-match
{
    margin: 2vh auto 0 auto;
}

https://jsfiddle.net/LL0xm1jg/4/

但是在小屏幕上 .btn-redirect 被放置在文本上

我尝试使用 Bootstrap 4 中的 flex 属性，但尝试失败了。有什么办法可以让它正常工作吗？

Answer 1

使用flexbox方式。为容器添加一个 flexbox util 类来填充高度。这个 flex-fill 类将是 included in Bootstrap 4.1 .

.flex-fill {
    flex: 1 1 auto;
}

https://www.codeply.com/go/YUw4uBdG1O

<div class="top js-top vh-100 bg-danger text-white d-flex">
    <div class="container flex-fill">
        <div class="row h-100 align-items-center py-1">
            <div class="col-lg-12 h-100 flex-fill d-flex flex-column align-items-center">
                <div class="my-auto text-center">
                    <h1 class="top-title">
                        <span class="top-title-1">text</span>
                        <span class="top-title-2">title</span>
                        <span class="top-title-3">text</span>
                    </h1>
                    <a href="" class="btn btn-redirect link-go-to-match">go</a>
                </div>
                <a href="#" class="btn-scroll-down js-btn-scroll-down"></a>
            </div>
        </div>
    </div>
</div>

使用 d-flex flex-column 将 col-lg-12 设为 Flexbox 列，然后将 h1 和 go 按钮分组到一个 div 中。使用 my-auto 将该 div 垂直居中，按钮自然会推到底部。