Detailed explanation of eight methods to achieve CSS page bottom fixed

<div class="dui-container">
<header>Header</header>
<main>Content</main>
<footer>Footer</footer>
</div>

.dui-container{
position: relative;
min-height: 100%;
}
main {
padding-bottom: 100px;
}
header, footer{
line-height: 100px;
height: 100px;
}
footer{
width: 100%;
position: absolute;
bottom: 0
}

<header>Header</header>
<main>Content</main>
<footer>Footer</footer>

html, body {
height: 100%;
}
main {
min-height: 100%;
padding-top: 100px;
padding-bottom: 100px;
margin-top: -100px;
margin-bottom: -100px;
}
header, footer{
line-height: 100px;
height: 100px;
}

<header>Header</header>
<main>Content</main>
<footer>Footer</footer>

main {
min-height: 100%;
padding-top: 100px;
padding-bottom: 100px;
}
header, footer{
line-height: 100px;
height: 100px;
}
header{
margin-bottom: -100px;
}
footer{
margin-top: -100px;
}

<header>Header</header>
<main>Content</main>
<footer>Footer</footer>

body{
display: flex;
min-height: 100vh;
flex-direction: column;
}
header,footer{
line-height: 100px;
height: 100px;
}
footer{
margin-top: auto;
}

<header>Header</header>
<main>Content</main>
<footer>Footer</footer>

main{
min-height: calc(100vh - 200px); /* This 200px is the height of the header and footer*/
}
header,footer{
height: 100px;
line-height: 100px;
}

<header>Header</header>
<main>Content</main>
<footer>Footer</footer>

body{
display: flex;
min-height: 100vh;
flex-direction: column;
}
main{
flex: 1
}

<header>Header</header>
<main>Content</main>
<footer>Footer</footer>

html {
height: 100%;
}
body {
min-height: 100%;
display: grid;
grid-template-rows: auto 1fr auto;
}
.footer {
grid-row-start: 3;
grid-row-end: 4;
}

<header>Header</header>
<main>Content</main>
<footer>Footer</footer>

body {
  min-height: 100%;
  display: table;
  width: 100%;
}
main {
  display: table-row;
  height: 100%;
}