calc 28 29 css

1.class{
2	width: calc(50% - 20px);
3}

1#page {
2  display: grid;
3  width: 100%;
4  height: 250px;
5  grid-template-areas: "head head"
6                       "nav  main"
7                       "nav  foot";
8  grid-template-rows: 50px 1fr 30px;
9  grid-template-columns: 150px 1fr;
10}
11
12#page > header {
13  grid-area: head;
14  background-color: #8ca0ff;
15}
16
17#page > nav {
18  grid-area: nav;
19  background-color: #ffa08c;
20}
21
22#page > main {
23  grid-area: main;
24  background-color: #ffff64;
25}
26
27#page > footer {
28  grid-area: foot;
29  background-color: #8cffa0;
30}
31

1.banniere {
2  position: absolute;
3  left: 40px;
4  width: calc(40px - 80px);
5  border: solid black 1px;
6  box-shadow: 1px 2px;
7  background-color: yellow;
8  padding: 6px;
9  text-align: center;
10  box-sizing: border-box;
11}
12

1.banner {
2  position: absolute;
3  left: 40px;
4  width: calc(100% - 70px);
5  border: solid black 1px;
6  box-shadow: 1px 2px;
7  background-color: yellow;
8  padding: 6px;
9  text-align: center;
10  box-sizing: border-box;
11}
12