1. insert css in html
1.1. inline
1.2. internal
1.3. external
2. style text
2.1. font-size
2.2. font-weight
2.3. text-decoration
2.4. text-tranform
2.5. text-alight
2.6. text-indent
2.7. text-justify
2.8. text-shadow
2.8.1. X
2.8.2. Y
2.8.3. X Y #color
3. 5 use to hidden element
3.1. visibility
3.1.1. hidden
3.1.2. visible
3.2. opacity
3.2.1. 0
3.2.2. 1
3.3. display
3.3.1. none
3.3.2. block,...
3.4. position
3.4.1. position: absolute; top: -9999px; left: -9999px;
3.5. clip-path: polygon(0px 0px,0px 0px,0px 0px,0px 0px);
4. padding
5. shadow
5.1. box-shadow
5.2. text-shadow
6. flex
6.1. display: flex;
6.1.1. flex-direction
6.1.1.1. row
6.1.1.2. column
6.1.1.3. row-reverse
6.1.1.4. column-reverse
6.1.2. justify-content
6.1.2.1. flex-start
6.1.2.2. flex-end
6.1.2.3. center
6.1.2.4. space-between
6.1.2.5. space-around
6.1.2.6. space-evenly
6.1.3. alight-items
6.1.3.1. the same justify-content
6.1.4. alight-content
6.1.4.1. the same
6.1.4.2. stretch (default)
6.2. (for child flex)
6.2.1. flex-grow
6.2.2. flex-basis
6.2.3. flex-shrink
7. position
7.1. relative
7.2. absolute
7.3. fixed
7.4. static
7.5. sticky
8. background
8.1. background-color
8.1.1. color
8.1.2. rgb()
8.1.3. # code-color
8.1.4. rgba()
8.2. background-image
8.2.1. url()
8.3. background-repeat
8.3.1. repeat X
8.3.2. repeat Y
8.3.3. repeat (X, Y)
8.3.4. no-repeat
8.4. background-position
8.4.1. top
8.4.2. right
8.4.3. bottom
8.4.4. left
8.4.5. %
8.4.6. px
8.4.7. center
8.5. background-size
8.5.1. cover
8.5.2. contain
8.5.3. length: %, px,...
8.6. background-attackment
8.6.1. :fixed
8.6.2. :scroll
8.7. background
9. css selector
9.1. class
9.2. id
9.3. attribute
9.4. element
10. border
11. margin
12. box-sizing
12.1. border-box
12.2. content-box
13. float
13.1. left
13.2. right
13.3. clear: float*;
13.3.1. both
13.3.2. left
13.3.3. right
14. Grid
14.1. display: grid
14.1.1. grid
14.1.2. inline grid
14.2. grid-template-column
14.2.1. track-size
14.2.1.1. fr unit
14.2.2. line-name
14.2.3. auto
14.2.4. repeat (3, 20px[col-start]) (if you want repeat value three time)
14.3. grid-template-row
14.3.1. the same column
14.4. grid-template-areas
14.4.1. ex: grid-areas: "header header header header" "sidebar . main main" " footer X 4" ;
14.5. grid-column-gap: <line-size>; grid-row-gap: <line-size>; // grid-gap: column row;
14.6. justify-items (doc)
14.6.1. start
14.6.2. end
14.6.3. center
14.6.4. stretch
14.7. alight-items (ngang)
14.7.1. the same justify-items
14.8. place-items : <alight-items> <justify-items>
14.9. justify-content
14.9.1. the same flex <justify-content>
14.10. alight-content
14.10.1. the same flex
14.11. place-content: <align-content> / <justify-content>
14.12. grid-auto-columns grid-auto-rows
14.12.1. value <track-size> <track-size>
14.12.2. use make item