:root{--tue-red:#C80000;--bg-from:#f5f5f5;--bg-to:#ffffff;--ink:#111111;}
body{color:var(--ink);} .btn-tue{background:var(--tue-red);color:#fff;} .btn-tue:hover{background:#a10000;}
.img-frame{overflow:hidden;border-radius:1rem;box-shadow:0 10px 15px -3px rgba(0,0,0,.1),0 4px 6px -4px rgba(0,0,0,.1);outline:1px solid rgba(0,0,0,.06);}

/* Lightbox overlay */
.lightbox {
  position: fixed;
  inset: 0;
  background: rgba(0,0,0,0.85);
  display: none;
  align-items: center;
  justify-content: center;
  padding: 2rem;
  z-index: 1000;
}

/* Show when targeted */
.lightbox:target {
  display: flex;
}

/* Lightbox image */
.lightbox img {
  max-width: 90vw;
  max-height: 90vh;
  border-radius: 0.75rem;
  box-shadow: 0 24px 60px rgba(0,0,0,0.6);
}

/* Click anywhere to close */
.lightbox-close {
  position: absolute;
  inset: 0;
  cursor: zoom-out;
}

.prose a { color: var(--tue-red); }