How to make inner divs scrollable in a lightning component?

To make inner divs scrollable within a Lightning Component, you can use CSS to define the desired scrolling behavior. Here's a basic example of how you can achieve this:

And in your CSS file:

.THIS .outer-container {
    /* Set the height and width of the outer container */
    height: 300px; /* Adjust as needed */
    width: 100%; /* Adjust as needed */
    overflow: auto; /* Enable scrolling */
}
.THIS .inner-container {
    /* Set the height and width of the inner container */
    height: 500px; /* Adjust as needed */
    width: 100%; /* Adjust as needed */
    /* Other styles for inner content */
}

In this example:

• The outer container (div.outer-container) defines the dimensions of the visible area. It has a fixed height, and if the content inside it exceeds this height, it will become scrollable vertically.
  
• The inner container (div.inner-container) contains the content you want to display. It should have dimensions larger than the outer container if you want scrolling to occur.
  
• By setting overflow: auto; on the outer container, you enable scrolling when the content exceeds the container's dimensions.
  

Adjust the height, width, and other styles according to your requirements.

Remember to replace .THIS with the appropriate namespace if you're using Salesforce Lightning Components. Also, consider responsive design and usability aspects when defining dimensions and scrolling behavior.