<a href="https://developer.mozilla.org/en-US/docs/Web/CSS/initial">initial</a>, <a href="https://developer.mozilla.org/en-US/docs/Web/CSS/inherit">inherit</a>, <a href="https://developer.mozilla.org/en-US/docs/Web/CSS/unset">unset</a>, and <a href="https://developer.mozilla.org/en-US/docs/Web/CSS/revert">revert</a> are used to set the value of a CSS property in a specific way, often for controlling the inheritance and resetting of property values.
initial: sets a CSS property to its default or initial value. It essentially resets the property to its default state. This can be useful when you want to override previously applied styles and start with the default property value.
<pre class="shiki github-dark shaku"><code>/* Reset the font-size property to its default value */p { font-size: initial;}</code></pre>
inherit: makes an element inherit the computed value of the specified property from its parent element. It establishes a direct inheritance relationship. It is often used to ensure that a child element inherits a property from its parent.
<pre class="shiki github-dark shaku"><code>/* Make the text color of a child element inherit from its parent */.parent { color: blue;}.child { color: inherit;}</code></pre>
unset: resets a property to its initial value if it has been set by the user, otherwise, it inherits the value from its parent. It combines the behavior of both <code>initial</code> and <code>inherit</code> based on whether a property has been previously set or not.
<pre class="shiki github-dark shaku"><code>/* Reset the background color to its initial value if set; otherwise, inherit it */div { background-color: unset;}</code></pre>
revert: is similar to <code>unset</code>, but it also considers the user agent (browser) stylesheet and resets the property to the user agent's default value if it exists. It essentially reverts the property to the browser's default value, even if it has been previously customized by user styles.
<pre class="shiki github-dark shaku"><code>/* Revert the font-weight property to the user agent's default value */h1 { font-weight: revert;}</code></pre>

initial, inherit, unset, and revert explained

They are not that commonly used, but if you create some common components, they might be very useful. MDN is good enough to get hold of them: initial,…