html, body {
  margin: 0;
  padding: 0;
  height: 100%;
  overflow-x: hidden;
}

body.index {
  background: url("img/background_index_1440p.png") no-repeat center center fixed;
  background-size: cover;
}

body.subpage {
  background: url("img/background_build_1440p.png") no-repeat center center fixed;
  background-size: cover;
}

nav {
  margin-top: 20px;
  display: flex;
  justify-content: center; /* wyśrodkowanie menu */
  gap: 40px;
}

.btn {
  position: relative;
  padding: 10px 30px;
  color: #ffffff;
  text-transform: uppercase;
  font-weight: bold;
  letter-spacing: 2px;
  text-decoration: none;
  background: none;
  border: none;
  cursor: pointer;
  font-size: 16px;
  font-family: Arial, Helvetica, sans-serif;
}

/* linia górna */
.btn::before {
  content: "";
  position: absolute;
  top: 0;
  left: 0;
  height: 2px;
  width: 0;
  background-color: #00bcd4;
  transition: width 0.3s ease;
}

/* linia dolna */
.btn::after {
  content: "";
  position: absolute;
  bottom: 0;
  right: 0;
  height: 2px;
  width: 0;
  background-color: #00bcd4;
  transition: width 0.3s ease;
}

/* efekt hover */
.btn:hover::before,
.btn.active::before {
  width: 100%;
}

.btn:hover::after,
.btn.active::after {
  width: 100%;
}

.btn:hover,
.btn.active {
  color: #00bcd4;
}

body {
  max-width: 100%;
  min-height: 100vh;
  overflow-x: hidden;
  overflow-y: hidden; /* 🔴 dodaj – usuwa pasek przewijania na PC */
}


/* MOBILE BACKGROUNDS – wymuszone dla telefonów */
@media (max-width: 768px) {
  body.index {
    background: url("img/background_index_mobile.png") no-repeat center center !important;
    background-size: cover !important;
    background-attachment: scroll !important;
  }

  body.subpage .menu {
    display: none;
    flex-direction: column;
    width: 100%;
    background: none; /* brak dodatkowego tła */
    padding: 0;        /* usuń padding */
}

}

/* Hamburger menu */
.menu-toggle {
  display: none;
  font-size: 28px;
  color: #ffffff;
  cursor: pointer;
  padding: 15px;
}

.menu {
  display: flex;
  gap: 40px;
}

/* Mobile styles */
@media (max-width: 768px) {
  nav {
    width: 100%;
    display: flex;
    flex-direction: column;
    align-items: center; /* hamburger na środku */
  }

  .menu-toggle {
    display: block;
    align-self: center; /* utrzymuje hamburgera na środku */
  }

  body.subpage .menu {
    display: none;
    flex-direction: column;
    width: 100%;
    background-color: #0a2239; /* kolor górnej części tła */
    padding: 15px 0;
    position: relative; /* menu w normalnym flow strony */
  }

  body.subpage .menu a {
    padding: 10px 20px;
    text-align: center;
  }

  body.subpage .menu.active {
    display: flex; /* rozwija się pod hamburgerem i przesuwa treść w dół */
  }

  body {
    overflow-y: auto; /* przewijanie na telefonach */
  }
  body.subpage .menu a {
    padding: 10px 0;
    text-align: center;
    background: none;   /* bez tła */
}

}