尝试使用填充和背景色的边框，然后为轮廓边框:

.round_outline {
  padding: 8px;
  background-color: white;
  border-radius: 50%;
  border: 1px solid black;
}

对我来说很管用。

No. Borders sit on the outside of the element and on the inside of the box-model margin area. Outlines sit on the inside of the element and the box-model padding area ignores it. It isn't intended for aesthetics. It's just to show the designer the outlines of the elements. In the early stages of developing an html document for example, a developer might need to quickly discern if they have put all of the skeletal divs in the correct place. Later on they may need to check if various buttons and forms are the correct number of pixels apart from each other.

边界本质上是审美的。与大纲不同，它们实际上是盒子模型的一部分，这意味着它们不会重叠设置为margin: 0的文本;边界的每一边都可以单独设置样式。

如果你试图应用一个角半径轮廓，我假设你使用它的方式大多数人使用边界。如果你不介意我问，outline的什么属性使它在边界上是可取的?

There is the solution if you need only outline without border. It's not mine. I got if from Bootstrap css file. If you specify outline: 1px auto certain_color, you'll get thin outer line around div of certain color. In this case the specified width has no matter, even if you specify 10 px width, anyway it will be thin line. The key word in mentioned rule is "auto". If you need outline with rounded corners and certain width, you may add css rule on border with needed width and same color. It makes outline thicker.

结合盒子阴影和轮廓。

李·海耶斯的回答有点小变化 我发现

input[type=text]:focus {
    box-shadow: 0 0 0 1pt red;
    outline-width: 1px;
    outline-color: red;
}

最后的效果非常干净。没有使用边界半径时的大小跳跃

通过设置outline-style: auto，我们可能很快就会看到我们的愿望

2030年见。

我刚刚找到了一个很好的解决方案，在看了所有的回复后，我还没有看到它发布。所以，这就是我所做的:

我为类创建了一个CSS规则，并为该规则使用了一个伪类:focus。我设置outline: none来去掉Chrome默认使用的浅蓝色无边框半径的“outline”。然后，在同样的:focus伪类中，轮廓不再存在，我添加了半径和边界属性。导致以下结果

outline: none;
border-radius: 5px;
border: 2px solid maroon;

当用户通过选项卡选择元素时，有一个带有边界半径的栗色轮廓。