finition header et page content id

style.css

@@ -11,6 +11,7 @@
 
   /* ENTÊTE */
   header {
+    z-index: 10000;
     font-family: 'police1';
     position: fixed;
     background: linear-gradient(315deg, rgba(77, 168, 112, 1) 0%, rgba(193, 4, 252, 1) 66%);
@@ -42,6 +43,8 @@
     position: inherit;
     width: 100vw;
     left: 0;
+    background-color: white;
+    background: linear-gradient(0deg, rgba(2,0,36,0) 0%, rgba(255,255,255,1) 40%); 
   }
 
   .menu-content{
@@ -81,12 +84,23 @@
     color: white;
   }
 
+  /* CONTENUS DE LA PAGE */
+  #page_content {
+    position: relative;
+    top: 15vh;
+    max-width: 80ch;
+    padding: 3em 1em;
+    margin: auto;
+    line-height: 1.75;
+    font-size: 1.25em;
+  }
 
   /* GRILLE */
   .grid-section{
-    display: block;
+    position: relative;
+    /* display: block; */
     /* position: fixed; */
-    margin: 30%;
+    /* margin: 30%; */
   }
 
   .grid-main {