Lesson 7: Building Responsive Layouts with Columns

📌 Objective: Learn how to use Bootstrap’s column system to create responsive page layouts.

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🔹 1. Introduction to Bootstrap’s Column System

Bootstrap’s grid system divides a row into 12 equal columns. You can adjust column widths based on screen sizes using breakpoints.

💡 Why Use Bootstrap Columns?
✔️ Creates flexible layouts that adjust to different screen sizes.
✔️ Eliminates the need for custom CSS media queries.
✔️ Easy-to-use column classes (.col-, .col-sm-*, .col-md-*).

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🔹 2. Creating Basic Column Layouts

1️⃣ Equal-Width Columns

If you don’t specify a column width, Bootstrap automatically distributes the space equally.

✅ Example: Equal-Width Columns

🔹 What happens?

• All columns take equal space inside the row.

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2️⃣ Defining Custom Column Widths

You can set column sizes by using .col-{size}-{number} classes.

✅ Example: Custom Column Widths

🔹 What happens?

• On medium (md) screens and above, the first column takes 4/12 (33%) and the second column takes 8/12 (66%).
• On small screens, the columns stack on top of each other.

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🔹 3. Creating Responsive Column Layouts

Use breakpoints to define different column widths at different screen sizes.

✅ Example: Responsive Columns

🔹 What happens?

• On small screens (sm), all columns take full width (col-sm-12) and stack.
• On medium screens (md), columns take half-width (col-md-6).
• On large screens (lg), they take one-third width (col-lg-4).

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🔹 4. Advanced Column Layouts

1️⃣ Auto-Sizing Columns (.col-auto)

Auto-sized columns adjust to the content size instead of using equal spacing.

✅ Example: Auto-Sized Columns

🔹 What happens?

• The first column takes only the necessary space for its content.
• The second column expands to fill the remaining space.

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2️⃣ Offset Columns (.offset-*)

Offsets add empty space before a column, useful for centering content.

✅ Example: Centering a Column Using Offsets

🔹 What happens?

• The column takes 6/12 width and is pushed 3 columns to the right, centering it.

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3️⃣ Reordering Columns (.order-*)

Change the display order of columns using .order-* classes.

✅ Example: Changing Column Order

🔹 What happens?

• On medium screens (md), the second column appears first, the first column appears second, and the third column stays last.

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4️⃣ Nesting Columns

You can place rows inside columns to create nested layouts.

✅ Example: Nested Columns

🔹 What happens?

• The first column contains another row with two nested columns inside.

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📝 Lesson Recap Quiz

🎯 Test your knowledge of Bootstrap columns.

📌 Multiple-Choice Questions (MCQs)

1️⃣ How many columns does Bootstrap’s grid system have?
a) 8
b) 10
c) 12
d) 16

✅ Correct Answer: c) 12

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2️⃣ What happens when you use .col-md-6?
a) The column takes full width on all screens
b) The column takes 6/12 width on medium screens and larger
c) The column stacks on large screens
d) The column disappears on medium screens

✅ Correct Answer: b) The column takes 6/12 width on medium screens and larger

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3️⃣ Which class allows a column to automatically adjust its size based on content?
a) .col-12
b) .col-md-6
c) .col-auto
d) .col-fluid

✅ Correct Answer: c) .col-auto

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📌 True or False

4️⃣ Bootstrap’s columns always take equal width unless specified.
✅ Answer: True

5️⃣ The .offset-* class moves a column to the left.
✅ Answer: False (It moves the column to the right.)

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🎯 Practical Challenge

✅ Create a 3-column layout where:

• The first column is auto-sized.
• The second column takes 6/12 width.
• The third column fills remaining space.
  ✅ Try reordering the columns using .order-* classes.
  ✅ Post your solution in the discussion forum for feedback!

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🎓 Lesson Summary

✅ Bootstrap columns (.col-*) create responsive layouts based on a 12-column grid.
✅ .col-auto makes a column adjust its size based on content.
✅ .offset-* adds empty space before a column.
✅ .order-* rearranges columns dynamically.
✅ Nesting columns allows for more complex layouts.