:root{
  --bg: #f6f7fb;
  --panel: #ffffff;
  --panel-2: #f3f7ff;
  --text: #0f172a;
  --text-muted: #475569;
  --border: rgba(15, 23, 42, 0.10);
  --shadow: 0 18px 40px rgba(15, 23, 42, 0.08);
  --accent: #3b82f6;     /* zakelijke blauw */
  --accent-2: #22c55e;   /* fris groen */
  --accent-3: #a78bfa;   /* zachte paars */
  --radius: 18px;
  --radius-sm: 12px;
  --maxw: 980px;
}

*{box-sizing:border-box}
html,body{height:100%}
body{
  margin:0;
  font-family: ui-sans-serif, system-ui, -apple-system, Segoe UI, Roboto, Arial, "Apple Color Emoji","Segoe UI Emoji";
  background:
    radial-gradient(1200px 800px at 15% 0%, rgba(59,130,246,0.12), transparent 60%),
    radial-gradient(900px 700px at 85% 25%, rgba(34,197,94,0.10), transparent 55%),
    radial-gradient(900px 700px at 65% 95%, rgba(167,139,250,0.10), transparent 55%),
    var(--bg);
  color: var(--text);
  line-height: 1.65;
}

.skip-link{
  position:absolute;
  left:-999px;
  top:10px;
  background: var(--panel);
  border: 1px solid var(--border);
  padding: 10px 12px;
  border-radius: 999px;
  box-shadow: var(--shadow);
}
.skip-link:focus{left:14px; z-index:9999}

.layout{
  display:flex;
  min-height:100vh;
}

.sidebar{
  width: 340px;
  padding: 18px;
  position: sticky;
  top:0;
  height: 100vh;
  overflow:auto;
  border-right: 1px solid var(--border);
  background:
    linear-gradient(180deg, rgba(255,255,255,0.78), rgba(255,255,255,0.55));
  backdrop-filter: blur(10px);
}

.brand{
  background: var(--panel);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 14px;
  box-shadow: var(--shadow);
}

.brand-link{
  display:flex;
  justify-content:center;
  text-decoration:none;
}
.logo{
  width: 300px;
  max-width: 100%;
  aspect-ratio: 1 / 1;
  display:grid;
  place-items:center;
  border-radius: calc(var(--radius) + 8px);
  overflow:hidden;
  background: linear-gradient(180deg, var(--panel-2), var(--panel));
  border: 1px solid var(--border);
}

.brand-text{ margin-top: 10px; }
.brand-title{
  font-weight: 800;
  letter-spacing: -0.02em;
  font-size: 18px;
}
.brand-subtitle{
  color: var(--text-muted);
  font-size: 13px;
}

.menu-toggle{
  margin-top: 14px;
  width: 100%;
  display:none;
  align-items:center;
  gap: 10px;
  justify-content:center;
  padding: 12px 14px;
  border-radius: 999px;
  border: 1px solid var(--border);
  background: var(--panel);
  box-shadow: var(--shadow);
  cursor:pointer;
  font-weight: 700;
}
.menu-toggle__icon{
  width: 16px;
  height: 12px;
  border-top: 2px solid var(--text);
  border-bottom: 2px solid var(--text);
  position:relative;
}
.menu-toggle__icon:before{
  content:"";
  position:absolute;
  left:0; right:0;
  top: 4px;
  border-top: 2px solid var(--text);
}

.nav{
  margin-top: 14px;
  display:flex;
  flex-direction:column;
  gap: 10px;
}

.nav-btn{
  text-decoration:none;
  color: var(--text);
  background: linear-gradient(180deg, rgba(255,255,255,0.95), rgba(243,247,255,0.95));
  border: 1px solid var(--border);
  padding: 12px 14px;
  border-radius: 999px;
  box-shadow: 0 10px 22px rgba(15,23,42,0.06);
  font-weight: 700;
  display:flex;
  align-items:center;
  justify-content:space-between;
  transition: transform 160ms ease, box-shadow 160ms ease, background 160ms ease, border-color 160ms ease;
}

.nav-btn:after{
  content:"›";
  color: rgba(71,85,105,0.9);
  font-weight: 900;
}

.nav-btn:hover{
  transform: translateX(4px);
  border-color: rgba(59,130,246,0.35);
  box-shadow: 0 16px 30px rgba(59,130,246,0.12);
  background: linear-gradient(180deg, rgba(255,255,255,1), rgba(236,245,255,1));
}

.nav-btn.active{
  border-color: rgba(34,197,94,0.45);
  box-shadow: 0 16px 30px rgba(34,197,94,0.12);
  background: linear-gradient(180deg, rgba(240,253,244,1), rgba(255,255,255,1));
}

.sidebar-note{
  margin-top: 14px;
  background: rgba(255,255,255,0.8);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 12px 14px;
}
.sidebar-note p{margin:0; color: var(--text-muted); font-size: 13px}

.content{
  flex: 1;
  padding: 34px 24px;
  display:flex;
  justify-content:center;
}
.page-header{
  max-width: var(--maxw);
  width: 100%;
  margin: 0 auto 18px auto;
  padding: 18px 20px;
  background: rgba(255,255,255,0.75);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
}
.kicker{
  display:inline-flex;
  padding: 6px 10px;
  border-radius: 999px;
  background: linear-gradient(90deg, rgba(59,130,246,0.16), rgba(34,197,94,0.14), rgba(167,139,250,0.14));
  border: 1px solid rgba(15,23,42,0.08);
  color: var(--text-muted);
  font-weight: 700;
  font-size: 12px;
}
.page-header h1{
  margin: 10px 0 6px 0;
  letter-spacing: -0.03em;
  line-height: 1.15;
  font-size: clamp(28px, 2.2vw, 40px);
}
.lede{
  margin: 0;
  color: var(--text-muted);
  max-width: 80ch;
}

.article{
  max-width: var(--maxw);
  width: 100%;
  margin: 0 auto;
  background: rgba(255,255,255,0.78);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  padding: 22px 22px;
}

.article p{
  margin: 0 0 14px 0;
}

.article h2, .article h3, .article h4{
  margin: 22px 0 10px 0;
  padding-top: 6px; /* extra breathing room above headings */
  letter-spacing: -0.02em;
}

.article h3{
  font-size: 20px;
}

.article a{
  color: var(--accent);
  text-decoration: none;
  font-weight: 800;
  border-bottom: 2px solid rgba(59,130,246,0.25);
  transition: border-color 160ms ease, color 160ms ease, background 160ms ease;
  padding: 1px 2px;
  border-radius: 6px;
}
.article a:hover{
  color: #0b4aa6;
  border-color: rgba(34,197,94,0.55);
  background: rgba(34,197,94,0.10);
}

.article ul, .article ol{
  margin: 0 0 16px 0;
  padding-left: 22px;
}
.article li{
  margin: 8px 0;
}
.article ul li::marker{ color: rgba(34,197,94,0.9) }
.article ol li::marker{ color: rgba(59,130,246,0.9); font-weight: 800 }

.footer{
  max-width: var(--maxw);
  width: 100%;
  margin: 18px auto 0 auto;
}
.footer-inner{
  display:flex;
  flex-wrap:wrap;
  gap: 10px 16px;
  justify-content:space-between;
  color: var(--text-muted);
  font-size: 13px;
  padding: 14px 16px;
  border-radius: var(--radius);
  border: 1px solid var(--border);
  background: rgba(255,255,255,0.7);
  box-shadow: 0 12px 24px rgba(15,23,42,0.06);
}

/* Responsive */
@media (max-width: 980px){
  .sidebar{ width: 300px; }
  .logo{ width: 260px; }
}
@media (max-width: 860px){
  .layout{ flex-direction: column; }
  .sidebar{
    width: 100%;
    height: auto;
    position: relative;
    border-right: none;
    border-bottom: 1px solid var(--border);
  }
  .menu-toggle{ display:flex; }
  .nav{
    display:none;
    margin-top: 12px;
  }
  .nav.open{ display:flex; }
  .content{ padding: 18px 14px; }
  .article{ padding: 18px 16px; }
}