如何使用Flexbox将卡片组件内的按钮固定在底部？

我用HTML和CSS搭建了基础页面，并用Flexbox实现了自定义卡片组件。但卡片内的「Read More」按钮无法和其他卡片的按钮对齐到底部（如图所示）：

请问仅通过Flexbox修改代码，如何让所有「Read More」按钮固定在卡片底部，保持同一水平线？

现有代码如下：

CSS代码 #

.container {
    max-width: 1200px;
    margin: 0 auto;
}

.main-content {
    display: flex;
    flex-wrap: wrap;
    justify-content: space-between;
}

img {
    max-width: 100%;
    display: block;
}

.entry {
    flex: 0 0 calc(33.33% - 1rem);
    margin-bottom: 1rem;
    background-color: white;
}

.entry .content {
    padding: 1rem;
    text-align: center;
    text-transform: uppercase;
}

h3 {
    margin: 0;
    font-weight: 700;
}

.content h3 {
    font-size: 0.9rem;
    line-height: 1.5rem;
}

.content span {
    color: #db008d;
}

.button {
    background-color: dodgerblue;
    color: white;
    text-decoration: none;
    padding: .6rem 2rem;
    margin-top: 1rem;
    display: inline-block;
}

.content {
    /*What to write here ?? */
}

HTML代码 #

<main class="main-content">
    <article class="entry">
        <img src="img/01.jpg" alt="entry image">
        <div class="content">
            <h3>Tips for Saving Money in your Next Travel</h3>
            <p>Published on: <span>July 19th, 2019</span></p>
            <p>By: <span>The Travel Blog</span></p>
            <a href="#" class="button">Read More</a>
        </div>
    </article>
    <article class="entry">
        <img src="img/02.jpg" alt="entry image">
        <div class="content">
            <h3>The Complete Guide for Traveling</h3>
            <p>Published on: <span>July 19th, 2019</span></p>
            <p>By: <span>The Travel Blog</span></p>
            <a href="#" class="button">Read More</a>
        </div>
    </article>
    <article class="entry">
        <img src="img/03.jpg" alt="entry image">
        <div class="content">
            <h3>Ultimate Guide to Take the best Pictures</h3>
            <p>Published on: <span>July 19th, 2019</span></p>
            <p>By: <span>The Travel Blog</span></p>
            <a href="#" class="button">Read More</a>
        </div>
    </article>
</main>

只需对两处CSS进行修改，完全基于Flexbox实现按钮对齐：

1. 修改.entry为垂直方向的Flex容器，让卡片内部元素（图片+内容区）垂直排列，同时确保内容区能自动填充剩余空间：

.entry {
    flex: 0 0 calc(33.33% - 1rem);
    margin-bottom: 1rem;
    background-color: white;
    display: flex;
    flex-direction: column;
}

2. 修改.content为垂直方向的Flex容器，通过justify-content: space-between让内容分布在容器上下，把按钮推到底部，同时保留原有的文本对齐和内边距：

.content {
    display: flex;
    flex-direction: column;
    justify-content: space-between;
    padding: 1rem;
    text-align: center;
    text-transform: uppercase;
    flex-grow: 1; /* 让内容区填满卡片剩余高度 */
}

另外，建议调整按钮的外边距，确保按钮始终贴底：

.button {
    background-color: dodgerblue;
    color: white;
    text-decoration: none;
    padding: .6rem 2rem;
    margin-top: auto; /* 替换原有的margin-top:1rem */
    display: inline-block;
}

这样修改后，所有卡片的「Read More」按钮会自动对齐到卡片底部，保持同一水平线，同时不影响其他内容的布局。

内容的提问来源于stack exchange，提问作者Balaji KR