Voeg scroll-margin toe aan secties zodat de sticky nav niet overlapt

De nav is sticky en 64px (h-16) hoog, maar de secties hadden geen
scroll-margin. scrollIntoView(block:'start') lijnde de sectietop dus
exact uit met de viewport-top, waardoor de sticky nav er precies
overheen schoof en de sectiekop (met name bij Over, nu direct na de
Hero) onder de nav verdween - het voelde alsof er te ver werd
doorgescrold. scroll-mt-16 op elke sectie houdt nu ruimte vrij voor
de nav.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

src/features/landing/components/AboutSection.tsx

@@ -2,7 +2,7 @@ import { aboutContent } from '../data/content';
 
 export function AboutSection() {
   return (
-    <section id="over" className="py-[88px]">
+    <section id="over" className="scroll-mt-16 py-[88px]">
       <div className="mx-auto max-w-[1080px] px-6">
         <div className="grid grid-cols-1 items-start gap-6 sm:grid-cols-[1.2fr_0.8fr] sm:grid-rows-[auto_1fr] sm:gap-12">
           <div className="order-1 mb-2 sm:col-start-1 sm:row-start-1 sm:mb-0">

src/features/landing/components/ContactSection.tsx

@@ -4,7 +4,7 @@ export function ContactSection() {
   const mailtoHref = `mailto:${contactInfo.email}?subject=${encodeURIComponent(contactInfo.mailSubject)}`;
 
   return (
-    <section id="contact" className="pb-[110px]">
+    <section id="contact" className="scroll-mt-16 pb-[110px]">
       <div className="mx-auto max-w-[1080px] px-6">
         <div className="rounded-[20px] border border-accent-line bg-gradient-to-br from-surface-2 to-surface px-10 py-14 text-center">
           <span className="font-mono block text-sm uppercase tracking-wider text-accent">

src/features/landing/components/PackagesSection.tsx

@@ -12,7 +12,7 @@ export function PackagesSection() {
   return (
     <section
       id="pakketten"
-      className="bg-gradient-to-b from-transparent via-surface/50 to-transparent py-[88px]"
+      className="scroll-mt-16 bg-gradient-to-b from-transparent via-surface/50 to-transparent py-[88px]"
     >
       <div className="mx-auto max-w-[1080px] px-6">
         <div className="mb-[52px]">

src/features/landing/components/ProcessSection.tsx

@@ -3,7 +3,7 @@ import { ProcessStep } from './ProcessStep';
 
 export function ProcessSection() {
   return (
-    <section id="werkwijze" className="py-[88px]">
+    <section id="werkwijze" className="scroll-mt-16 py-[88px]">
       <div className="mx-auto max-w-[1080px] px-6">
         <div className="mb-[52px]">
           <span className="font-mono block text-sm uppercase tracking-wider text-accent">