:root {
  --hero-img: url('https://th.bing.com/th/id/OIP.VhOrrCC9k6k_i66XGrKLVAHaE8?w=280&h=186&c=7&r=0&o=7&pid=1.7&rm=3');
}
body { overflow-x:hidden; }

.nav-link.active { font-weight: bold; }
.nav-link:hover { color: var(--bs-primary); }

.hero {
  min-height: 70vh;
  background: var(--hero-img) center/cover no-repeat fixed;
  color: #fff;
  position: relative;
}
.hero::before {
  content:""; position:absolute; inset:0;
  background: rgba(0,0,0,.4);
}
.hero .container { position: relative; }

.parallax { height: 40vh; }
.parallax-inner {
  height:100%;
  background: var(--hero-img) center/cover no-repeat fixed;
}
@media(max-width:991px){ .hero,.parallax-inner{background-attachment:scroll;} }

.back-to-top { position:fixed; right:1rem; bottom:1rem; display:none; }