/* Full-page background image */
body {
  margin: 0;
  min-height: 100vh;
  background-image: url("back.jpg"); /* change to your image path */
  background-size: cover;
  background-position: center;
  background-repeat: no-repeat;
  font-family: Arial, sans-serif;
  color: #000000;
}

/* Horizontal navigation */
.main-nav ul {
  list-style: none;
  margin: 0;
  padding: 0;
  display: flex;               
  justify-content: center;     
  background-color: rgba(0, 0, 0, 0.6);
}

.main-nav li {
  margin: 0 20px;
}

.main-nav a {
  display: block;
  padding: 15px 0;
  color: #ffffff;
  text-decoration: none;
  font-weight: 600;
}

.main-nav a:hover {
  color: #7DF9FF;
}

/* Center hero text */
.hero {
  display: flex;
  justify-content: center;   /* horizontal center */
  align-items: center;       /* vertical center */
  text-align: center;
  height: calc(100vh - 50px); /* adjust if your nav is taller/shorter */
}

.hero h1 {
  font-size: 3.5rem;         /* large font */
  font-weight: 700;          /* bold */
  margin: 0;
}

.hero h1 span {
  font-weight: 900;          /* extra bold for LYSISTECH */
}