Since different browsers have different default styles, many elements have default inner and outer margins.
To unify these styles, you can introduce normalize.css https://necolas.github.io/normalize.css/ into the page.
The npm download command is:
npm install normalize.css
Or directly enter the link, click download, copy the style to the page and use it.
The v8.0.1 code is as follows:
/*! normalize.css v8.0.1 | MIT License | github.com/necolas/normalize.css */
/* Document
================================================== ======================== */
/**
* 1. Correct the line height in all browsers.
* 2. Prevent adjustments of font size after orientation changes in iOS.
*/
html {
line-height: 1.15; /* 1 */
-webkit-text-size-adjust: 100%; /* 2 */
}
/* Sections
================================================== ======================== */
/**
* Remove the margin in all browsers.
*/
body {
margin: 0;
}
/**
* Render the `main` element consistently in IE.
*/
main {
display: block;
}
/**
* 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;
}
/* Grouping content
================================================== ======================== */
/**
* 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 */
}
/**
* 1. Correct the inheritance and scaling of font size in all browsers.
* 2. Correct the odd `em` font sizing in all browsers.
*/
pre {
font-family: monospace, monospace; /* 1 */
font-size: 1em; /* 2 */
}
/* Text-level semantics
================================================== ======================== */
/**
* Remove the gray background on active links in IE 10.
*/
a {
background-color: transparent;
}
/**
* 1. Remove the bottom border in Chrome 57-
* 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 */
}
/**
* Add the correct font weight in Chrome, Edge, and Safari.
*/
b,
strong {
font-weight: bolder;
}
/**
* 1. Correct the inheritance and scaling of font size in all browsers.
* 2. Correct the odd `em` font sizing in all browsers.
*/
code,
kbd,
sample {
font-family: monospace, monospace; /* 1 */
font-size: 1em; /* 2 */
}
/**
* 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;
}
/* Forms
================================================== ======================== */
/**
* 1. Change the font styles in all browsers.
* 2. Remove the margin in Firefox and Safari.
*/
button,
input,
optgroup,
select,
textarea {
font-family: inherit; /* 1 */
font-size: 100%; /* 1 */
line-height: 1.15; /* 1 */
margin: 0; /* 2 */
}
/**
* 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;
}
/**
* Correct the inability to style clickable types in iOS and Safari.
*/
button,
[type="button"],
[type="reset"],
[type="submit"] {
-webkit-appearance: button;
}
/**
* 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;
}
/**
* Correct the padding in Firefox.
*/
fieldset {
padding: 0.35em 0.75em 0.625em;
}
/**
* 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 */
}
/**
* Add the correct vertical alignment in Chrome, Firefox, and Opera.
*/
progress {
vertical-align: baseline;
}
/**
* Remove the default vertical scrollbar in IE 10 + .
*/
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 in Chrome and Safari on macOS.
*/
[type="search"]::-webkit-search-decoration {
-webkit-appearance: none;
}
/**
* 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 */
}
/* Interactive
================================================== ======================== */
/*
* Add the correct display in Edge, IE 10+, and Firefox.
*/
details {
display: block;
}
/*
* Add the correct display in all browsers.
*/
summary {
display: list-item;
}
/* Misc
================================================== ======================== */
/**
* Add the correct display in IE 10 + .
*/
template {
display: none;
}
/**
* Add the correct display in IE 10.
*/
[hidden] {
display: none;
}
The reason why reset.css is not needed is because reset.css will clear all default styles, while normalize.css retains some useful default styles.
The URL of reset.css is: https://meyerweb.com/eric/tools/css/reset/.