:root {
  --overlay: rgba(0,0,0,.35);
}

html, body { height: 100%; margin:0; }
body {
  font: 16px/1.5 system-ui, -apple-system, Segoe UI, Roboto, Helvetica, Arial, sans-serif;
  color: #fff;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  background:
    linear-gradient(var(--overlay), var(--overlay)),
    url("../images/construction.jpg") center center / cover no-repeat fixed;
}

@media (max-width: 768px) {
  body {
    background:
      linear-gradient(var(--overlay), var(--overlay)),
      url("../images/construction.jpg") center center / cover no-repeat;
  }
}

.center {
  flex: 1;
  display: grid;
  place-items: center;
  text-align: center;
  padding: 24px;
  text-shadow: 0 2px 10px rgba(0,0,0,.35);
}

h1 {
  margin: 0 0 .25em;
  font-weight: 800;
  letter-spacing: .2px;
  font-size: clamp(24px, 4.5vw, 40px);
}
p { margin: 0; font-size: clamp(14px, 2.5vw, 18px); opacity: .95; }

.logo-footer {
  text-align: center;
  padding: 24px;
}

.logo-footer a {
  display: inline-block;
  background: rgba(255,255,255,0.8);   /* półprzezroczyste jasne tło */
  padding: 12px 20px;
  border-radius: 12px;                 /* zaokrąglone rogi */
  box-shadow: 0 4px 16px rgba(0,0,0,0.2);
  transition: background .2s ease, transform .2s ease;
}

.logo-footer a:hover {
  background: rgba(255,255,255,0.95);
  transform: scale(1.05);
}

.logo-footer img {
  height: 120px;   /* duże logo */
  width: auto;
  display: block;
  opacity: 0.95;
}