以下是100种CSS写法，其中某些方法可能需要一定的CSS知识和经验，但它们对于优化和完善网页布局和样式非常有用。
1. #id {}
2. .class {}
3. a {}
4. div {}
5. span {}
6. p {}
7. h1 {}
8. h2 {}
9. h3 {}
10. img {}
11. ul {}
12. ol {}
13. li {}
14. table {}
15. tr {}
16. td {}
17. th {}
18. form {}
19. input {}
20. label {}
21. textarea {}
22. button {}
23. select {}
24. option {}
25. a:hover {}
26. a:visited {}
27. a:active {}
28. a:focus {}
29. div:hover {}
30. div:active {}
31. div:focus {}
32. .class:hover {}
33. .class:visited {}
34. .class:active {}
35. .class:focus {}
36. #id:hover {}
37. #id:visited {}
38. #id:active {}
39. #id:focus {}
40. margin {}
41. padding {}
42. border {}
43. width {}
44. height {}
45. display {}
46. float {}
47. clear {}
48. position {}
49. top {}
50. left {}
51. bottom {}
52. right {}
53. overflow {}
54. z-index {}
55. font-size {}
56. font-weight {}
57. font-family {}
58. line-height {}
59. font-style {}
60. text-transform {}
61. text-decoration {}
62. text-align {}
63. color {}
64. background-color {}
65. background-image {}
66. background-position {}
67. background-size {}
68. background-repeat {}
69. opacity {}
70. box-shadow {}
71. border-radius {}
72. text-shadow {}
73. transform {}
74. transition {}
75. animation {}
76. @media {}
77. @import {}
78. @font-face {}
79. @keyframes {}
80. :before {}
81. :after {}
82. content {}
83. cursor {}
84. visibility {}
85. filter {}
86. cursor:url() {}
87. text-overflow {}
88. white-space {}
89. word-spacing {}
90. letter-spacing {}
91. @support {}
92. @-webkit-keyframes {}
93. @-moz-keyframes {}
94. @-o-keyframes {}
95. @-ms-keyframes {}
96. text-indent {}
97. list-style-type {}
98. list-style-image {}
99. list-style-position {}
100. text-indent {}以上是100种常见的CSS写法，掌握这些写法将使你在实现页面布局和样式方面更加得心应手。记得在深入学习CSS时，要注重实践和理论相结合。