MR_BaxtiyoR, # MR_BaxtiyoR (21.10.2018 / 20:02)
uDesign, web sahifalar uchun ham #id dan foydalanishar ekan
#header {
background-color:black;
color:white;
text-align:center;
padding:5px;
}
#nav {
line-height:30px;
bBularning farqi
idni chaqirish uchun

Kod · HTML1 qator

<div id="test">birnima<div>

deb id testni chaqirasiz.
classda esa

Kod · HTML1 qator

<div class="test">birnima</div>

dev chaqirasiz.
Bular ikkalasi ham .css faylga yozilaveradi lekin
idni

Kod · CSS11 qator

#test {

    background-color: black;

    color: white;

    margin: 20px;

    padding: 20px;

}

shaklida yozasiz
class da esa

Kod · CSS11 qator

.test {

    background-color: black;

    color: white;

    margin: 20px;

    padding: 20px;

}

shakilda yozasiz. Kimga qaysinisi qulay bo'lsa shuni yozadi buni qizig'i yo'q lekin idga classga qaraganda ko'proq ish qilsa bo'ladi. Tushundingiz deb umid qilaman.

https://www.w3schools.com/html/tryit.asp?filename=tryhtml_classes_capitals
https://www.w3schools.com/html/tryit.asp?filename=tryhtml_id_css shu ikkalasini ko'rishni maslahat beraman