重置样式非常多，凡是一个前端开发人员肯定有一个常用的重置CSS文件并知道如何使用它们。他们是盲目的在做还是知道为什么这么做呢？原因是不同的浏览器对一些元素有不同的默认样式，如果你不处理，在不同的浏览器下会存在必要的风险，或者更有戏剧性的性发生。
* {
padding: 0;
margin: 0;
}
这是最普遍最简单的CSS重设，将所有元素的padding和margin值都设为0，可以避免一些浏览器在理解这两个属性默认值上的”分歧”。
/*! normalize.css v4.1.1 | MIT License | github.com/necolas/normalize.css */ /**
* 1. Change the default font family in all browsers (opinionated).
* 2. Prevent adjustments of font size after orientation changes in IE and iOS.
*/ html {
font-family: sans-serif; /* 1 */
-ms-text-size-adjust: 100%; /* 2 */
-webkit-text-size-adjust: 100%; /* 2 */
} /**
* Remove the margin in all browsers (opinionated).
*/ body {
margin: 0;
} /* HTML5 display definitions
========================================================================== */ /**
* Add the correct display in IE 9-.
* 1. Add the correct display in Edge, IE, and Firefox.
* 2. Add the correct display in IE.
*/ article,
aside,
details, /* 1 */
figcaption,
figure,
footer,
header,
main, /* 2 */
menu,
nav,
section,
summary { /* 1 */
display: block;
} /**
* Add the correct display in IE 9-.
*/ audio,
canvas,
progress,
video {
display: inline-block;
} /**
* Add the correct display in iOS 4-7.
*/ audio:not([controls]) {
display: none;
height: 0;
} /**
* Add the correct vertical alignment in Chrome, Firefox, and Opera.
*/ progress {
vertical-align: baseline;
} /**
* Add the correct display in IE 10-.
* 1. Add the correct display in IE.
*/ template, /* 1 */
[hidden] {
display: none;
} /* Links
========================================================================== */ /**
* 1. Remove the gray background on active links in IE 10.
* 2. Remove gaps in links underline in iOS 8+ and Safari 8+.
*/ a {
background-color: transparent; /* 1 */
-webkit-text-decoration-skip: objects; /* 2 */
} /**
* Remove the outline on focused links when they are also active or hovered
* in all browsers (opinionated).
*/ a:active,
a:hover {
outline-width: 0;
} /* Text-level semantics
========================================================================== */ /**
* 1. Remove the bottom border in Firefox 39-.
* 2. Add the correct text decoration in Chrome, Edge, IE, Opera, and Safari.
*/ abbr[title] {
border-bottom: none; /* 1 */
text-decoration: underline; /* 2 */
text-decoration: underline dotted; /* 2 */
} /**
* Prevent the duplicate application of `bolder` by the next rule in Safari 6.
*/ b,
strong {
font-weight: inherit;
} /**
* Add the correct font weight in Chrome, Edge, and Safari.
*/ b,
strong {
font-weight: bolder;
} /**
* Add the correct font style in Android 4.3-.
*/ dfn {
font-style: italic;
} /**
* Correct the font size and margin on `h1` elements within `section` and
* `article` contexts in Chrome, Firefox, and Safari.
*/ h1 {
font-size: 2em;
margin: 0.67em 0;
} /**
* Add the correct background and color in IE 9-.
*/ mark {
background-color: #ff0;
color: #000;
} /**
* Add the correct font size in all browsers.
*/ small {
font-size: 80%;
} /**
* Prevent `sub` and `sup` elements from affecting the line height in
* all browsers.
*/ sub,
sup {
font-size: 75%;
line-height: 0;
position: relative;
vertical-align: baseline;
} sub {
bottom: -0.25em;
} sup {
top: -0.5em;
} /* Embedded content
========================================================================== */ /**
* Remove the border on images inside links in IE 10-.
*/ img {
border-style: none;
} /**
* Hide the overflow in IE.
*/ svg:not(:root) {
overflow: hidden;
} /* Grouping content
========================================================================== */ /**
* 1. Correct the inheritance and scaling of font size in all browsers.
* 2. Correct the odd `em` font sizing in all browsers.
*/ code,
kbd,
pre,
samp {
font-family: monospace, monospace; /* 1 */
font-size: 1em; /* 2 */
} /**
* Add the correct margin in IE 8.
*/ figure {
margin: 1em 40px;
} /**
* 1. Add the correct box sizing in Firefox.
* 2. Show the overflow in Edge and IE.
*/ hr {
box-sizing: content-box; /* 1 */
height: 0; /* 1 */
overflow: visible; /* 2 */
} /* Forms
========================================================================== */ /**
* 1. Change font properties to `inherit` in all browsers (opinionated).
* 2. Remove the margin in Firefox and Safari.
*/ button,
input,
select,
textarea {
font: inherit; /* 1 */
margin: 0; /* 2 */
} /**
* Restore the font weight unset by the previous rule.
*/ optgroup {
font-weight: bold;
} /**
* Show the overflow in IE.
* 1. Show the overflow in Edge.
*/ button,
input { /* 1 */
overflow: visible;
} /**
* Remove the inheritance of text transform in Edge, Firefox, and IE.
* 1. Remove the inheritance of text transform in Firefox.
*/ button,
select { /* 1 */
text-transform: none;
} /**
* 1. Prevent a WebKit bug where (2) destroys native `audio` and `video`
* controls in Android 4.
* 2. Correct the inability to style clickable types in iOS and Safari.
*/ button,
html [type="button"], /* 1 */
[type="reset"],
[type="submit"] {
-webkit-appearance: button; /* 2 */
} /**
* Remove the inner border and padding in Firefox.
*/ button::-moz-focus-inner,
[type="button"]::-moz-focus-inner,
[type="reset"]::-moz-focus-inner,
[type="submit"]::-moz-focus-inner {
border-style: none;
padding: 0;
} /**
* Restore the focus styles unset by the previous rule.
*/ button:-moz-focusring,
[type="button"]:-moz-focusring,
[type="reset"]:-moz-focusring,
[type="submit"]:-moz-focusring {
outline: 1px dotted ButtonText;
} /**
* Change the border, margin, and padding in all browsers (opinionated).
*/ fieldset {
border: 1px solid #c0c0c0;
margin: 0 2px;
padding: 0.35em 0.625em 0.75em;
} /**
* 1. Correct the text wrapping in Edge and IE.
* 2. Correct the color inheritance from `fieldset` elements in IE.
* 3. Remove the padding so developers are not caught out when they zero out
* `fieldset` elements in all browsers.
*/ legend {
box-sizing: border-box; /* 1 */
color: inherit; /* 2 */
display: table; /* 1 */
max-width: 100%; /* 1 */
padding: 0; /* 3 */
white-space: normal; /* 1 */
} /**
* Remove the default vertical scrollbar in IE.
*/ textarea {
overflow: auto;
} /**
* 1. Add the correct box sizing in IE 10-.
* 2. Remove the padding in IE 10-.
*/ [type="checkbox"],
[type="radio"] {
box-sizing: border-box; /* 1 */
padding: 0; /* 2 */
} /**
* Correct the cursor style of increment and decrement buttons in Chrome.
*/ [type="number"]::-webkit-inner-spin-button,
[type="number"]::-webkit-outer-spin-button {
height: auto;
} /**
* 1. Correct the odd appearance in Chrome and Safari.
* 2. Correct the outline style in Safari.
*/ [type="search"] {
-webkit-appearance: textfield; /* 1 */
outline-offset: -2px; /* 2 */
} /**
* Remove the inner padding and cancel buttons in Chrome and Safari on OS X.
*/ [type="search"]::-webkit-search-cancel-button,
[type="search"]::-webkit-search-decoration {
-webkit-appearance: none;
} /**
* Correct the text style of placeholders in Chrome, Edge, and Safari.
*/ ::-webkit-input-placeholder {
color: inherit;
opacity: 0.54;
} /**
* 1. Correct the inability to style clickable types in iOS and Safari.
* 2. Change font properties to `inherit` in Safari.
*/ ::-webkit-file-upload-button {
-webkit-appearance: button; /* 1 */
font: inherit; /* 2 */
}
normalize.css没有重置所有的样式风格，但仅提供了一套合理的默认样式值。既能让众多浏览器达到一致和合理，但又不扰乱其他的东西（如粗体的标题）。
一种清除,一种保留兼容