Media Queries

What is a Media Query?

A media query allows you to define specific CSS styles based on conditions such as:

• screen size (width/height),
• device type (print, screen),
• resolution,
• dark or light mode, etc.

It is a fundamental tool of responsive design, to adapt the layout to all devices: desktop, tablet, mobile.

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Basic syntax

@media condition {
  /* CSS styles here */
}

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Practical example (breakpoints)

/* Style par défaut : Desktop */
body {
  background: white;
  font-size: 18px;
}

/* Tablette : max-width 768px */
@media (max-width: 768px) {
  body {
    background: #f0f0f0;
    font-size: 16px;
  }
}

/* Mobile : max-width 480px */
@media (max-width: 480px) {
  body {
    background: #e0e0e0;
    font-size: 14px;
  }
}

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Common breakpoints (indicative)

Device	Max width (max-width)
Mobile	480px to 600px
Tablet	768px to 1024px
Laptop	1024px to 1440px
Large desktop	1440px+

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Some useful conditions

1. By screen width

@media (min-width: 1024px) { ... }
@media (max-width: 768px) { ... }

2. Portrait/Landscape orientation

@media (orientation: portrait) { ... }
@media (orientation: landscape) { ... }

3. Light/Dark mode

@media (prefers-color-scheme: dark) {
  body {
    background: black;
    color: white;
  }
}

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Tip: combining multiple conditions

@media (min-width: 600px) and (max-width: 900px) {
  /* Styles for screens between 600px and 900px */
}

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Best practices

• Use mobile-first media queries: base styles for small screens, then min-width for larger ones.
• Avoid overloading everything in a single rule.
• Keep a clear structure (desktop / tablet / mobile).
• Use fluid units (em, %, rem) whenever possible.

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Complete example

.card {
  width: 400px;
}

@media (max-width: 768px) {
  .card {
    width: 90%;
  }
}

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@media vs @media screen

1. @media

@media (max-width: 768px) {
  /* styles here */
}

This is the most common form and the one most used today.

By default, screen is implied, so you can safely omit screen in 99% of cases.

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2. @media screen

@media screen and (max-width: 768px) {
  /* styles here */
}

Here you specify that the rules apply only to screens (and not to printing, for example).

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Other media types

Type	Description
all	Tous les types de médias (défaut)
screen	Écrans (ordinateurs, tablettes, etc.)
print	Impression papier
speech	Synthèse vocale (lecture d’écran)

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Best practices

• If you only target screens, you can simply use @media (shorter, more readable).

• If you want to exclude print or speech, explicitly use:

  @media screen and (max-width: 768px) { ... }

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Summary

Syntax	Recommended?	Notes
@media (...)	✅ YES	Enough in 99% of cases
@media screen and (...)	✅ YES	More explicit, useful if you also handle print
@media print	✅ YES	For print styles