> For the complete documentation index, see [llms.txt](https://lochiwei.gitbook.io/web/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://lochiwei.gitbook.io/web/css/responsive-design.md).

# Responsive Design

{% tabs %}
{% tab title="responsive web design" %}

* render at the width of the device.
* responsive image size.
* adapt to different screen width (media query).
  {% endtab %}

{% tab title="HTML" %}

```markup
<!-- make the content render at the width of the device -->
<meta name="viewport" content="width=device-width,initial-scale=1.0" />
```

{% endtab %}

{% tab title="CSS" %}

```css
/* 讓圖片不超過螢幕寬度 */
img { max-width: 100%; }
```

{% endtab %}

{% tab title="media query" %}

```css
/* breakpoint: screen width >= 800px */
@media screen and (min-width: 800px) { /* styles */ }
```

{% endtab %}
{% endtabs %}

## key points

* (**smallest screen first**) the first **rules** we write **outside of a media query** should be our **starter or "base" rules** for the most basic devices, which we then enhance for more capable devices and **larger screens**.


---

# Agent Instructions
This documentation is published with GitBook. GitBook is the documentation platform designed so that both humans and AI agents can read, navigate, and reason over technical content effectively. Learn more at gitbook.com.

## Querying This Documentation
If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question.

Perform an HTTP GET request on the current page URL with the `ask` query parameter, and the optional `goal` query parameter:

```
GET https://lochiwei.gitbook.io/web/css/responsive-design.md?ask=<question>&goal=<endgoal>
```

`ask` is the immediate question: it should be specific, self-contained, and written in natural language.
`goal` is optional and describes the broader end goal you are ultimately trying to accomplish on behalf of the user. GitBook uses it to tailor the answer towards what is most useful for that goal.

The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.