:root{
  --bg: #0b1220;
  --surface: #0f1b33;
  --card: #0e1a30;
  --text: #e8edf6;
  --muted: #b6c2d6;
  --brand: #3b82f6;
  --brand-2: #1d4ed8;
  --line: rgba(255,255,255,.10);
  --radius: 16px;
  --shadow: 0 12px 30px rgba(0,0,0,.35);
  --max: 1100px;
}

*{ box-sizing:border-box; }
html{ scroll-behavior:smooth; }
body{
  margin:0;
  font-family: "Poppins", system-ui, -apple-system, Segoe UI, Roboto, Arial, sans-serif;
  color: var(--text);
  background: radial-gradient(1000px 600px at 20% 10%, rgba(59,130,246,.25), transparent 60%),
              radial-gradient(900px 600px at 90% 40%, rgba(29,78,216,.25), transparent 55%),
              var(--bg);
  line-height:1.6;
}

a{ color: inherit; text-decoration:none; }
img{ max-width:100%; display:block; }

.container{
  width: min(100% - 2rem, var(--max));
  margin-inline:auto;
}

.skip-link{
  position:absolute;
  left:-999px;
  top:auto;
  width:1px;
  height:1px;
  overflow:hidden;
}
.skip-link:focus{
  left: 1rem;
  top: 1rem;
  width:auto;
  height:auto;
  background:#fff;
  color:#000;
  padding:.5rem .75rem;
  border-radius:10px;
  z-index:9999;
}

/* ===================== Header / Nav ===================== */
.site-header{
  position: sticky;
  top: 0;
  z-index: 50;
  background: rgba(11,18,32,.72);
  backdrop-filter: blur(10px);
  border-bottom: 1px solid var(--line);
}

.header-inner{
  display:flex;
  align-items:center;
  justify-content:space-between;
  padding: 1rem 0;
  gap: 1rem;
}

.brand{
  display:flex;
  flex-direction:column;
  gap:.1rem;
}
.brand .logo{
  font-weight:700;
  letter-spacing:.2px;
  font-size: 1.15rem;
}
.brand .tagline{
  color: var(--muted);
  font-size: .85rem;
}

.nav{
  display:flex;
  gap:.35rem;
  flex-wrap:wrap;
  align-items:center;
  justify-content:flex-end;
}
.nav a{
  padding: .55rem .75rem;
  border-radius: 12px;
  color: var(--muted);
  border: 1px solid transparent;
}
.nav a:hover{
  color: var(--text);
  border-color: var(--line);
  background: rgba(255,255,255,.04);
}
.nav a[aria-current="page"]{
  color: var(--text);
  background: rgba(59,130,246,.15);
  border-color: rgba(59,130,246,.35);
}

/* ===================== Hero ===================== */
.hero{
  padding: 2.25rem 0 1.5rem;
}
.hero-grid{
  display:grid;
  grid-template-columns: 1.2fr .8fr;
  gap: 1.25rem;
  align-items:stretch;
}
.hero-card{
  background: linear-gradient(180deg, rgba(255,255,255,.06), rgba(255,255,255,.03));
  border: 1px solid var(--line);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  overflow:hidden;
}
.hero-content{
  padding: 1.5rem 1.5rem 1.25rem;
}
.hero h1{
  margin: 0 0 .6rem;
  font-size: clamp(1.6rem, 2.4vw, 2.3rem);
  line-height:1.15;
}
.hero p{
  margin: 0 0 1.1rem;
  color: var(--muted);
}
.hero-actions{
  display:flex;
  gap:.75rem;
  flex-wrap:wrap;
}
.btn{
  display:inline-block;
  padding: .7rem 1rem;
  border-radius: 14px;
  border: 1px solid var(--line);
  background: rgba(255,255,255,.04);
  color: var(--text);
  font-weight: 600;
}
.btn.primary{
  background: linear-gradient(180deg, var(--brand), var(--brand-2));
  border-color: rgba(59,130,246,.55);
}
.btn:hover{ transform: translateY(-1px); }
.btn:active{ transform: translateY(0); }

.hero-media{
  height:100%;
  min-height: 260px;
  position:relative;
}
.hero-media img{
  width:100%;
  height:100%;
  object-fit:cover;
}
.hero-media .overlay{
  position:absolute;
  inset:0;
  background: linear-gradient(90deg, rgba(11,18,32,.85), rgba(11,18,32,.15));
}

/* ===================== Sections ===================== */
.section{
  padding: 1.5rem 0 2.25rem;
}
.section-title{
  margin: 0 0 1rem;
  font-size: 1.25rem;
  letter-spacing:.2px;
}

.grid{
  display:grid;
  gap: 1rem;
}

.card{
  background: rgba(255,255,255,.04);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  overflow:hidden;
  box-shadow: 0 10px 20px rgba(0,0,0,.25);
}
.card img{
  width:100%;
  height: 160px;
  object-fit: cover;
}
.card-body{
  padding: 1rem 1rem 1.1rem;
}
.card h3{
  margin: 0 0 .35rem;
  font-size: 1.05rem;
}
.card p{
  margin:0 0 .85rem;
  color: var(--muted);
  font-size: .95rem;
}
.card .card-actions{
  margin-top:auto;
}

/* index: 4 -> 2 -> 1 */
.grid.cols-4{ grid-template-columns: repeat(4, 1fr); }

/* universiteiten: 3 -> 2 -> 1 */
.grid.cols-3{ grid-template-columns: repeat(3, 1fr); }

/* ===================== Gallery ===================== */
.gallery{
  display:grid;
  grid-template-columns: 2fr 1fr 1fr;
  gap: 1rem;
}
.gallery .big{
  grid-row: span 2;
}
.gallery img{
  width:100%;
  height: 100%;
  object-fit: cover;
  border-radius: 14px;
  border: 1px solid var(--line);
}
.gallery .thumb{
  height: 170px;
}
.gallery .big img{
  height: 360px;
}

/* ===================== Flexbox ===================== */
.tips{
  display:flex;
  gap: 1rem;
  flex-wrap: wrap;
}
.tip{
  flex: 1 1 calc(33.333% - 1rem);
  min-width: 220px;
  background: rgba(255,255,255,.04);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 1rem;
  box-shadow: 0 10px 20px rgba(0,0,0,.25);
}
.tip h3{
  margin:0 0 .35rem;
}
.tip p{
  margin:0;
  color: var(--muted);
}

/* ===================== Forms ===================== */
.form{
  background: rgba(255,255,255,.04);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 1.25rem;
  box-shadow: var(--shadow);
}
.form-grid{
  display:grid;
  grid-template-columns: 1fr 1fr;
  gap: 1rem;
}
label{
  display:block;
  font-weight: 600;
  margin: 0 0 .4rem;
}
input, textarea{
  width:100%;
  padding: .75rem .85rem;
  border-radius: 12px;
  border: 1px solid rgba(255,255,255,.16);
  background: rgba(11,18,32,.55);
  color: var(--text);
  outline:none;
}
textarea{ min-height: 140px; resize: vertical; }
input:focus, textarea:focus{
  border-color: rgba(59,130,246,.65);
  box-shadow: 0 0 0 4px rgba(59,130,246,.15);
}
.form-actions{
  margin-top: 1rem;
}

/* ===================== Footer ===================== */
.site-footer{
  border-top: 1px solid var(--line);
  background: rgba(10,16,30,.65);
}
.footer-grid{
  display:grid;
  grid-template-columns: 2fr 1fr 1fr;
  gap: 1rem;
  padding: 1.5rem 0;
}
.footer-grid h4{
  margin:0 0 .5rem;
}
.footer-grid p, .footer-grid a{
  color: var(--muted);
  margin:0;
  font-size:.95rem;
}
.footer-bottom{
  border-top: 1px solid var(--line);
  padding: .9rem 0;
  color: var(--muted);
  font-size: .9rem;
  display:flex;
  justify-content:space-between;
  gap:1rem;
  flex-wrap:wrap;
}

/* ===================== Responsive ===================== */
@media (max-width: 900px){
  .hero-grid{ grid-template-columns: 1fr; }
  .hero-media{ min-height: 240px; }
  .grid.cols-4{ grid-template-columns: repeat(2, 1fr); }
  .grid.cols-3{ grid-template-columns: repeat(2, 1fr); }
  .gallery{ grid-template-columns: 1fr 1fr; }
  .gallery .big{ grid-column: 1 / -1; }
  .gallery .big img{ height: 300px; }
  .gallery .thumb{ height: 160px; }
  .form-grid{ grid-template-columns: 1fr; }
  .footer-grid{ grid-template-columns: 1fr 1fr; }
}
@media (max-width: 560px){
  .grid.cols-4{ grid-template-columns: 1fr; }
  .grid.cols-3{ grid-template-columns: 1fr; }
  .footer-grid{ grid-template-columns: 1fr; }
  .nav{ justify-content:flex-start; }
}