青少年编程与数学 01-006 设计网页的外观 17课题、默认值
CSS属性的默认值。
“习惯如果不被加强，就会逐渐消失。”
“A habit not strengthened is a habit left to wither.”
—— 罗伯特·博尔顿 (Robert Bolton) | 作家、商业顾问 | 年代未知
“我们的习惯，就像我们最好的朋友，可以让我们走向成功，也可以让我们走向失败。”
“Our habits determine our effectiveness, can set us up for success, or tear us down.”
—— 帕特里克·金 (Patrick King) | 作家、生活教练 | 年代未知
课题摘要
CSS属性的默认值。
课题要求
了解CSS属性的默认值。
CSS属性的默认值
css属性在没有设置的时候，也是有值的，这就是默认值。列在下面，方便查看。
| 元素 | 默认的 CSS 值 |
|---|---|
| a:link | color: (internal value);text-decoration: underline;cursor: auto; |
| a:visited | color: (internal value);text-decoration: underline;cursor: auto; |
| a🔗active | color: (internal value); |
| a:visited:active | color: (internal value); |
| abbr | None. |
| address | display: block;font-style: italic; |
| area | display: none; |
| article | display: block; |
| aside | display: block; |
| audio | None. |
| b | font-weight: bold; |
| base | None. |
| bdi | None. |
| bdo | unicode-bidi: bidi-override; |
| blockquote | display: block;margin-top: 1em;margin-bottom: 1em;margin-left: 40px;margin-right: 40px; |
| body | display: block;margin: 8px; |
| body:focus | outline: none; |
| br | None. |
| button | None |
| canvas | None. |
| caption | display: table-captiontext-align: center; |
| cite | font-style: italic; |
| code | font-family: monospace; |
| col | display: table-column; |
| colgroup | display: table-column-group |
| datalist | display: none; |
| dd | display: block;margin-left: 40px; |
| del | text-decoration: line-through; |
| details | display: block; |
| dfn | font-style: italic; |
| dialog | None. |
| div | display: block; |
| dl | display: block;margin-top: 1em;margin-bottom: 1em;margin-left: 0;margin-right: 0; |
| dt | display: block; |
| em | font-style: italic; |
| embed:focus | outline: none; |
| fieldset | display: block;margin-left: 2px;margin-right: 2px;padding-top: 0.35em;padding-bottom: 0.625em;padding-left: 0.75em;padding-right: 0.75em;border: 2px groove (internal value); |
| figcaption | display: block; |
| figure | display: block;margin-top: 1em;margin-bottom: 1em;margin-left: 40px;margin-right: 40px; |
| footer | display: block; |
| form | display: block;margin-top: 0em; |
| h1 | display: block;font-size: 2em;margin-top: 0.67em;margin-bottom: 0.67em;margin-left: 0;margin-right: 0;font-weight: bold; |
| h2 | display: block;font-size: 1.5em;margin-top: 0.83em;margin-bottom: 0.83em;margin-left: 0;margin-right: 0;font-weight: bold; |
| h3 | display: block;font-size: 1.17em;margin-top: 1em;margin-bottom: 1em;margin-left: 0;margin-right: 0;font-weight: bold; |
| h4 | display: block;margin-top: 1.33em;margin-bottom: 1.33em;margin-left: 0;margin-right: 0;font-weight: bold; |
| h5 | display: block;font-size: .83em;margin-top: 1.67em;margin-bottom: 1.67em;margin-left: 0;margin-right: 0;font-weight: bold; |
| h6 | display: block;font-size: .67em;margin-top: 2.33em;margin-bottom: 2.33em;margin-left: 0;margin-right: 0;font-weight: bold; |
| head | display: none; |
| header | display: block; |
| hr | display: block;margin-top: 0.5em;margin-bottom: 0.5em;margin-left: auto;margin-right: auto;border-style: inset;border-width: 1px; |
| html | display: block;html:focusoutline: none; |
| i | font-style: italic; |
| iframe:focus | outline: none; |
| iframe[seamless] | display: block; |
| img | display: inline-block; |
| input | None. |
| ins | text-decoration: underline; |
| kbd | font-family: monospace; |
| label | cursor: default; |
| legend | display: block;padding-left: 2px;padding-right: 2px;border: none; |
| li | display: list-item; |
| link | display: none; |
| main | None. |
| map | display: inline; |
| mark | background-color: yellow;color: black; |
| menu | display: block;list-style-type: disc;margin-top: 1em;margin-bottom: 1em;margin-left: 0;margin-right: 0;padding-left: 40px; |
| menuitem | None. |
| meta | None. |
| meter | None. |
| nav | display: block; |
| noscript | None. |
| object:focus | outline: none; |
| ol | display: block;list-style-type: decimal;margin-top: 1em;margin-bottom: 1em;margin-left: 0;margin-right: 0;padding-left: 40px; |
| optgroup | None. |
| option | None. |
| output | display: inline; |
| p | display: block;margin-top: 1em;margin-bottom: 1em;margin-left: 0;margin-right: 0; |
| param | display: none; |
| picture | None. |
| pre | display: block;font-family: monospace;white-space: pre;margin: 1em 0; |
| progress | None. |
| q | display: inline; |
| q::before | content: open-quote; |
| q::after | content: close-quote; |
| rp | None. |
| rt | line-height: normal; |
| ruby | None. |
| s | text-decoration: line-through; |
| samp | font-family: monospace; |
| script | display: none; |
| section | display: block; |
| select | None. |
| small | font-size: smaller; |
| source | None. |
| span | None. |
| strike | text-decoration: line-through; |
| strong | font-weight: bold; |
| style | display: none; |
| sub | vertical-align: sub;font-size: smaller; |
| summary | display: block; |
| sup | vertical-align: super;font-size: smaller; |
| table | display: table;border-collapse: separate;border-spacing: 2px;border-color: gray; |
| tbody | display: table-row-group;vertical-align: middle;border-color: inherit; |
| td | display: table-cell;vertical-align: inherit; |
| template | None. |
| textarea | None. |
| tfoot | display: table-footer-group;vertical-align: middle;border-color: inherit; |
| th | display: table-cell;vertical-align: inherit;font-weight: bold;text-align: center; |
| thead | display: table-header-group;vertical-align: middle;border-color: inherit; |
| time | None. |
| title | display: none; |
| tr | display: table-row;vertical-align: inherit;border-color: inherit; |
| track | None. |
| u | text-decoration: underline; |
| ul | display: block;list-style-type: disc;margin-top: 1em;margin-bottom: 1 em;margin-left: 0;margin-right: 0;padding-left: 40px; |
| var | font-style: italic; |
| video | None. |
| wbr | None. |
尽量记住这些默认值。
附录一、人物介绍：尤雨溪
尤雨溪（Evan You），是Vue.js框架的创始人和项目领导者，同时也是一位独立开源开发者。他毕业于科尔盖特大学（Colgate University），并在帕森斯设计学院（Parsons School of Design）获得了设计和技术的艺术硕士学位。尤雨溪曾在Google Creative Labs和Meteor Development Group工作。
尤雨溪在大学时的专业并非计算机科学，而是室内艺术和艺术史。在帕森斯设计学院读硕士期间，他偶然接触到了JavaScript，并被这门编程语言深深吸引，从而开启了自己的前端开发生涯。2014年2月，他开发了Vue.js，这是一个通过简洁的API提供高效数据绑定和灵活组件系统的前端开发库。
尤雨溪以其对开源项目的贡献而闻名，Vue.js因其轻量级、简单易学等优势，获得了广泛的用户基础和社区支持。Vue.js的设计哲学是“渐进式框架”，旨在为不同水平的开发者提供适应其需求的工具和API，无论是初学者还是专家，都能在Vue.js中找到合适的工具来处理他们的项目。
尤雨溪的人生道路和职业选择体现了他对技术的热爱和对艺术的执着追求。他的成长经历和成功故事激励了许多人，证明了非计算机专业背景的人才同样可以在技术领域取得卓越成就。他的工作和成就在软件开发社区中得到了广泛的认可和尊重。
