逐行高亮显示代码

好的，我可以为您提供一个Python的示例代码，演示如何逐行高亮显示代码：

import time

def countdown(n: int):
    """
    Count down from n to 0 and print each number with a delay of 1 second.
    """
    for i in range(n, -1, -1):
        print(f"Countdown: {i}")
        time.sleep(1)

countdown(5)

以上是一个简单的倒计时程序，当您运行它时，它将从5开始倒数到0，并且每秒钟会打印出当前倒计时的数字。

如果您想要逐行高亮显示这段代码，您可以使用类似下面的HTML和CSS代码：

<pre>
    <code class="python">
        <span class="line">import time</span>

        <span class="line">def countdown(n: int):</span>
        <span class="line">    """</span>
        <span class="line">    Count down from n to 0 and print each number with a delay of 1 second.</span>
        <span class="line">    """</span>
        <span class="line">    for i in range(n, -1, -1):</span>
        <span class="line">        print(f"Countdown: {i}")</span>
        <span class="line">        time.sleep(1)</span>

        <span class="line">countdown(5)</span>
    </code>
</pre>

<style>
    .line {
        display: block;
        padding: 0.5em;
    }
    .python {
        color: #000000;
        background-color: #f8f8f8;
        font-family: "Consolas", "Courier New", monospace;
        font-size: 14px;
        line-height: 1.5em;
        overflow-x: auto;
        padding: 1em;
    }
</style>

这段HTML和CSS代码将会逐行高亮显示前面的Python代码。具体实现方式是使用`<pre>`和`<code>`标签来包裹代码，然后使用CSS来定义每一行的样式。