对于大部分前端用户这两个内容咱们都了解，rgba 最后的a设置透明度，但是通过16进制设置透明度咱们并不是常用，但是不影响设置，
比如网易云的红色为：#E20000
如果不用rbga咱们之前的写法为：
<div className={'color'} style={{backgroundColor: '#E20000',opacity: '0.2'}}>
<span>文字</span>
</div>
改进
<div className={'color'} style={{backgroundColor: '#E2000033'}}>
<span>文字</span>
</div>
#E2000033最后两位33就表示设置该颜色的透明度为20%。
十六进制颜色不透明度对照表
不透明度 - 代码
100% - FF
99% - FC
98% - FA
97% - F7
96% - F5
95% - F2
94% - F0
93% - ED
92% - EB
91% - E8
90% - E6
89% - E3
88% - E0
87% - DE
86% - DB
85% - D9
84% - D6
83% - D4
82% - D1
81% - CF
80% - CC
79% - C9
78% - C7
77% - C4
76% - C2
75% - BF
74% - BD
73% - BA
72% - B8
71% - B5
70% - B3
69% - B0
68% - AD
67% - AB
66% - A8
65% - A6
64% - A3
63% - A1
62% - 9E
61% - 9C
60% - 99
59% - 96
58% - 94
57% - 91
56% - 8F
55% - 8C
54% - 8A
53% - 87
52% - 85
51% - 82
50% - 80
49% - 7D
48% - 7A
47% - 78
46% - 75
45% - 73
44% - 70
43% - 6E
42% - 6B
41% - 69
40% - 66
39% - 63
38% - 61
37% - 5E
36% - 5C
35% - 59
34% - 57
33% - 54
32% - 52
31% - 4F
30% - 4D
29% - 4A
28% - 47
27% - 45
26% - 42
25% - 40
24% - 3D
23% - 3B
22% - 38
21% - 36
20% - 33
19% - 30
18% - 2E
17% - 2B
16% - 29
15% - 26
14% - 24
13% - 21
12% - 1F
11% - 1C
10% - 1A
9% - 17
8% - 14
7% - 12
6% - 0F
5% - 0D
4% - 0A
3% - 08
2% - 05
1% - 03
0% - 00