fix(guide): restructure curriculum guide articles (#36501)

* fix: restructure certifications guide articles
* fix: added 3 dashes line before prob expl
* fix: added 3 dashes line before hints
* fix: added 3 dashes line before solutions

guide/english/certifications/responsive-web-design/css-grid/add-gaps-faster-with-grid-gap/index.md

@@ -1,24 +1,36 @@
 ---
 title: Add Gaps Faster with grid-gap
 ---
-## Add Gaps Faster with grid-gap
+# Add Gaps Faster with grid-gap
 
+---
+## Problem Explanation
 In this challenge you are required to use "grid-gap" to define a row gap and a column gap.
 
-### Hint
+
+---
+## Hints
+
+### Hint 1
 
 You can define the gap for the row and column by declaring the following in the .container CSS codeblock:
 
-````css
+```css
 grid-gap: 'row-gap' 'column-gap';
-````
+```
 
 and inserting the desired parameters for 'row-gap' and 'column-gap'.
 
-### Solution
+
+---
+## Solutions
+
+<details><summary>Solution 1 (Click to Show/Hide)</summary>
 
 Since the challenge requires you to create a 10px gap between the rows and a 20px gap between the columns, add the following code to the .container CSS codeblock:
 
-````css
+```css
 grid-gap: 10px 20px;
-````
+```
+
+</details>