Borders Are Not Just Decoration

1. Border Properties

For a border to appear, it needs a command of three parts: Thickness, Type, and Color.

border: 2px dashed #f00;
  • solid: solid line.
  • dashed: dashed line.
  • dotted: dots.
  • double: double line (requires at least 3px thickness).

2. Border vs Outline

Many confuse these two properties.

  • Border: Takes space in the box model. Increasing border thickness " pushes " neighbors apart.
  • Outline: Drawn OVER the element. Doesn't take space.
    • When to use: For :focus indication (blue frame when selected with tab).

3. Border-radius: Not Just Circles

You can set rounding for each corner separately.

border-radius: 10px 50px 10px 50px; /* Leaf effect */