Hi Tan,
CSS for alignment varies for every structure. One CSS that works for another site may not work for yours.
Give the parent Container Block holding everything a class of set-container-full-height. Then try adding this CSS in Appearance > Customize > Additional CSS:
.gb-container.set-container-full-height, .gb-container.set-container-full-height > .gb-inside-container {
height: 100%;
}
.gb-container.set-container-full-height > .gb-inside-container {
display: flex;
flex-direction: column;
}
.gb-container.set-container-full-height > .gb-inside-container > .gb-container {
flex: 1 1 auto;
}
.gb-container.set-container-full-height > .gb-inside-container > .gb-container > .gb-inside-container {
height: 100%;
display: flex;
flex-direction: column;
}
.gb-container.set-container-full-height > .gb-inside-container > .gb-container > .gb-inside-container > :last-child {
margin-top: auto;
}