Reset default style css reset

i recently saw a word called css reset. what is css what about reset? i understand it as resetting css, which means resetting the default style.

i mentioned in the default style under html that some tag elements have a default attribute value under html. when we write css pages, in order to avoid repeatedly defining them in css, we need to redefine them. set default style (css reset). everyone's usage and writing methods are different. i found a survey article about css reset. you can take a look at the survey on the proportion of css reset used abroad.

next, i also checked two domestic websites and used firebug to press f12 to see how to write their css reset. of?
taobao (www.taobao.com):

html 
{ 
overflow-x:auto; 
overflow-y:scroll; 
} 
body, dl, dt, dd, ul, 
ol, li, pre, form, fieldset, input, p, blockquote, th, td { 
font-weight:400; 
margin:0; 
padding:0; 
} 
h1, h2, h3, h4, h4, h5 { 
margin:0; 
padding:0; 
} 
body { 
background-color:#ffffff; 
color:#666666; 
font-family:helvetica,arial,sans-serif; 
font-size:12px; 
padding:0 
10px; 
text-align:left; 
} 
select { 
font-size:12px; 
} 
table { 
border-collapse:collapse; 
} 
fieldset, img { 
border:0 
none; 
} 
fieldset { 
margin:0; 
padding:0; 
} 
fieldset p { 
margin:0; 
padding:0 0 0 8px; 
} 
legend { 
display:none; 
} 
address, caption, em, strong, th, i { 
font-style:normal; 
font-weight:400; 
} 
table caption { 
margin-left:-1px; 
} 
hr { 
border-bottom:1px solid #ffffff; 
border-top:1px solid #e4e4e4; 
border-width:1px 0; 
clear:both; 
height:2px; 
margin:5px 0; 
overflow:hidden; 
} 
ol, ul { 
list-style-image:none; 
list-style-position:outside; 
list-style-type:none; 
} 
caption, th 
{ 
text-align:left; 
} 
q:before, q:after, blockquote:before, 
blockquote:after { 
content:""; 
}

baidu youa (www.youa.com): (the architecture is basically modeled after yui)

body { 
font-family:arial,helvetica,sans-serif; 
font-size:13px; 
font-size-adjust:none; 
font-stretch:normal; 
font-style:normal; 
font-variant:normal; 
font-weight:normal; 
line-height:1.4; 
text-align:center; 
} 
body, ul, ol, dl, dd, h1, h2, h3, h4, h5, h6, 
p, form, fieldset, legend, input, textarea, select, button, th, td { 
margin:0; 
padding:0; 
} 
h1, h2, h3, h4, h5, h6 { 
font-size:100%; 
font-weight:normal; 
} 
table { 
font-size:inherit; 
} 
input, select { 
font-family:arial,helvetica,clean,sans-serif; 
font-size:100%; 
font-size-adjust:none; 
font-stretch:normal; 
font-style:normal; 
font-variant:normal; 
font-weight:normal; 
line-height:normal; 
} 
button { 
overflow:visible; 
} 
th, em, strong, b, address, cite { 
font-style:normal; 
font-weight:normal; 
} 
li { 
list-style-image:none; 
list-style-position:outside; 
list-style-type:none; 
} 
img, fieldset { 
border:0 none; 
} 
ins { 
text-decoration:none; 
}

in the book "beyond css", it is recommended that we start resetting all default styles when we build a website:

/* normalizes margin,padding */ 
body,div,dl,dt,dd,ul,ol,li,h1,h2,h3,h4,h5,h6,pre,form,fieldset,input,p,blockquote,th,td 
{ margin:0;padding:0} 
/* normalizes font-size for headers */ 
h1,h2,h3,h4,h5,h6 { font-size:100%} 
/* removes list-style from lists */ 
ol,ul { list-style:none } 
/* normalizes font-size and font-weight to 
normal */ 
address,caption,cite,code,dfn,em,strong,th,var { font-size:normal; 
font-weight:normal } 
/* removes list-style from lists */ 
table { 
border-collapse:collapse; border-spacing:0 } 
/* removes border from fieldset 
and img */ 
fieldset,img { border:0 } 
/* left-aligns text in caption and 
th */ 
caption,th { text-align:left } 
/* removes quotation marks from q 
*/ 
q:before,q:after { content:''}

so how do we reset css when we actually write code?
i personally recommend using (eric meyer and yui) css reset

Eric Meyer's Reset: 
html, body, 
div, span, applet, object, iframe, 
h1, h2, h3, h4, h5, h6, p, blockquote, 
pre, 
a, abbr, acronym, address, big, cite, code, 
del, dfn, em, font, 
img, ins, kbd, q, s, samp, 
small, strike, strong, sub, sup, tt, var, 
b, 
u, i, center, 
dl, dt, dd, ol, ul, li, 
fieldset, form, label, legend, 
table, caption, tbody, tfoot, thead, tr, th, td { 
margin: 0; 
padding: 0; 
border: 0; 
outline: 0; 
font-size: 100%; 
vertical-align: baseline; 
background: transparent; 
} 
body { 
line-height: 1; 
} 
ol, ul { 
list-style: none; 
} 
blockquote, q { 
quotes: none; 
} 
blockquote:before, 
blockquote:after, 
q:before, q:after { 
content: ''; 
content: none; 
} 
/* remember to define focus styles! */ 
:focus { 
outline: 0; 
} 
/* remember to highlight inserts somehow! */ 
ins { 
text-decoration: none; 
} 
del { 
text-decoration: line-through; 
} 
/* tables still need 'cellspacing="0"' in the markup */ 
table { 
border-collapse: collapse; 
border-spacing: 0; 
} 
YUI: 
body,div,dl,dt,dd,ul,ol,li,h1,h2,h3,h4,h5,h6,pre,form,fieldset,input,textarea,p,blockquote,th,td 
{ 
margin:0; 
padding:0; 
} 
table { 
border-collapse:collapse; 
border-spacing:0; 
} 
fieldset,img { 
border:0; 
} 
address,caption,cite,code,dfn,em,strong,th,var { 
font-style:normal; 
font-weight:normal; 
} 
ol,ul { 
list-style:none; 
} 
caption,th { 
text-align:left; 
} 
h1,h2,h3,h4,h5,h6 { 
font-size:100%; 
font-weight:normal; 
} 
q:before,q:after { 
content:''; 
} 
abbr,acronym { border:0; 
}

combined with their css how to write reset, and based on your actual situation, you will definitely be able to write a perfect css reset that suits your website.