feat: add header component

- add font Adwaita Sans
- add font styles
- add app styles
- add data json

src/lib/styles/app.css

@@ -1,12 +1,26 @@
 :root {
+    --color-body-background: oklch(0.21 0.034 264.665);
+    --color-header-border: oklab(0.623 -0.0378409 -0.210628 / 0.3);
+    --color-dark-blue: oklab(0.21 -0.00316128 -0.0338527 / 0.95);
+    --color-text-primary: oklch(0.872 0.01 258.338);
+    --color-accent-primary: oklch(70.7% 0.165 254.624);
+    --color-accent-secondary:oklch(0.585 0.233 277.117);
 
+    --z-index-header: 50;
+}
+
+:root {
+    font-size: 16px;
+    color: var(--color-text-primary);
 }
 
 * {
     box-sizing: border-box;
 }
 
-body {
-    font-family: 'AdwaitaMono', sans-serif;
+html, body {
+    position: relative;
     margin: unset;
+    background-color: var(--color-body-background);
+    font-family: 'AdwaitaSans', 'AdwaitaMono', sans-serif;
 }