Add section illustrations and custom logo font (Space Grotesk)

- Add Google Font Space Grotesk for logo, coral-colored "Turku"
- Add SVG illustrations: server rack (Palvelut), wind turbines (Energia),
  chat bubbles (UKK), envelope/location (Yhteystiedot)
- CSS positioning for illustration-left/right with responsive hiding

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

style.css

@@ -114,9 +114,10 @@ a:hover {
     align-items: center;
     gap: 10px;
     color: var(--color-white);
-    font-size: 1.25rem;
+    font-family: 'Space Grotesk', var(--font-family);
+    font-size: 1.3rem;
     font-weight: 400;
-    letter-spacing: -0.01em;
+    letter-spacing: -0.02em;
 }
 
 .logo:hover {
@@ -125,6 +126,7 @@ a:hover {
 
 .logo strong {
     font-weight: 700;
+    color: var(--color-primary-light);
 }
 
 .logo-icon {
@@ -1351,6 +1353,31 @@ a:hover {
     height: 100%;
 }
 
+/* === Section Illustrations === */
+.illustration-left,
+.illustration-right {
+    position: absolute;
+    top: 0;
+    bottom: 0;
+    width: 220px;
+    pointer-events: none;
+    z-index: 0;
+}
+
+.illustration-left {
+    left: 0;
+}
+
+.illustration-right {
+    right: 0;
+}
+
+.illustration-left svg,
+.illustration-right svg {
+    width: 100%;
+    height: 100%;
+}
+
 /* === Animations === */
 .fade-in {
     opacity: 0;
@@ -1371,7 +1398,9 @@ a:hover {
         opacity: 0.5;
     }
 
-    .blueprint-decoration {
+    .blueprint-decoration,
+    .illustration-left,
+    .illustration-right {
         display: none;
     }