CSS / Reference / border-style: Border Patterns, Side Order, and Hidden Conflicts

border-style specifies the border patterns on the four sides of a box. The initial style is none, so a width and color alone need not produce a visible border.

Syntax and value choices

Initial values are not necessarily the values assigned to HTML elements by the browser’s stylesheet. Inspect the actual result in developer tools’ Computed panel.

.card { border: 2px solid #006c9c; }
.box { border-style: solid dashed dotted double; }

For supported values and conditions, see MDN border-style.

Run the example and compare results

Save this complete code as css-reference-10622-example.html in UTF-8 and open it in a browser. Keep its demonstration styles in that file rather than pasting them into a site-wide stylesheet.

<!doctype html>
<html lang="en">
<head>
<meta charset="utf-8">
<meta name="viewport" content="width=device-width, initial-scale=1">
<title>border-style comparison example</title>
<style>
body { margin: 0; color: #20242b; background: #fff; font: 16px/1.7 "Malgun Gothic", sans-serif; }
#demo { padding: 24px; max-width: 820px; margin: auto; }
h1 { font-size: 22px; margin: 0 0 20px; }
.samples { display: flex; flex-wrap: wrap; gap: 24px; }
.label { margin: 0 0 8px; font-weight: 700; }
.target, .reference { width: 220px; height: 100px; padding: 12px; border-width: 6px; border-color: #006c9c; }
.target { border-style: solid dashed dotted double; }
.reference { border-style: none; }
</style>
</head>
<body>
<main id="demo">
<h1>border-style comparison</h1>
<section class="samples"><div class="a"><p class="label">A different style on each side</p><div class="target">Border comparison</div></div><div class="b"><p class="label">none</p><div class="reference">Border comparison</div></div></section>
</main>
</body>
</html>

Inspect top, right, bottom, and left on the first box. The none box paints no border, even when a border width was specified.

Side ordering

Four values start at the top and proceed clockwise. Two values mean top/bottom and left/right; three mean top, left/right, and bottom. Match each side’s style with its width and color.

Shorthand resets and table conflicts

A later border shorthand can reset earlier side styles. none and hidden look similar on an ordinary box but have different precedence in collapsed-table border conflicts. A none style can also make the computed width zero.

Compare none and hidden in collapsed tables

Save this complete document as css-reference-10622-practice.html in UTF-8 and open it in a browser. Test it as a separate file rather than nesting it inside another example.

<!doctype html>
<html lang="en">
<head>
  <meta charset="utf-8">
  <meta name="viewport" content="width=device-width, initial-scale=1">
  <title>Compare none and hidden in collapsed tables</title>
  <style>
    body { margin: 16px; color: #20242b; font: 16px/1.7 sans-serif; }
    main { max-width: 52rem; margin: auto; }
    h1 { font-size: 1.35rem; }
    .samples { display: flex; flex-wrap: wrap; gap: 24px; }
    .samples > * { max-width: 100%; min-width: 0; }
    :focus-visible { outline: 3px solid #005fcc; outline-offset: 3px; }
table { border-collapse:collapse;margin-bottom:20px; } td { padding:12px; } .left { border-right:6px solid #006c9c; } .none { border-left:6px none #006c9c; } .hidden { border-left:6px hidden #006c9c; }
  </style>
</head>
<body>
<main>
  <h1>Compare none and hidden in collapsed tables</h1>
<p>none</p><table><tr><td class="left">Left</td><td class="none">Right</td></tr></table><p>hidden</p><table><tr><td class="left">Left</td><td class="hidden">Right</td></tr></table>
</main>
</body>
</html>

The neighbor’s solid border wins beside none; hidden suppresses other styles on that shared collapsed border. Change only .hidden to none, compare both tables, then restore hidden. Distinguish ordinary invisible borders from collapsed-table conflict precedence.

For using borders and shadows together on components, see CSS Borders, Rounded Corners, and Shadows. Related properties to compare alongside these conditions are border-width.

When the result is missing or unexpected

• Check for none when width and color are correct but no border appears.
• Use sufficient width and inspect zoom if a double border looks solid.