html, body {
  margin: 0;
  padding: 0;
  height: 100%;
  overflow: hidden; /* Prevents scrollbars */
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Arial, sans-serif;
}

body {
  background-image: url('background.png');
  background-size: cover;
  background-position: center;
  background-repeat: no-repeat;
  color: white;
  height: 100vh; /* Ensure full viewport height */
  margin: 0; /* Remove any default margin */
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
}

body::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background-color: rgba(0, 0, 0, 0.5); /* Semi-transparent dark overlay */
  z-index: -1; /* Place the overlay behind the content */
}

h1 {
  font-size: clamp(24px, 5vw, 36px);
  font-weight: bold;
  /*background: linear-gradient(105deg, #800000, #FFA500, #FFFF00, #00FF00, #7FFFD4, #C0C0C0, #FF00FF);*/
  background: linear-gradient(135deg, #CC7722, #FFA500, #FAC898, #FFE5B4, #FFF5EE);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text; /* Fallback for non-webkit browsers */
  color: transparent;
}

h1:hover {
  background: linear-gradient(135deg, #FFF5EE, #FFE5B4, #FAC898, #FFA500, #CC7722);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text; /* Fallback for non-webkit browsers */
  color: transparent;
}

.button-link {
  font-size: clamp(14px, 2vw, 16px);
}

.overlay {
  background-color: rgba(0, 0, 0, 0.5);
  width: 100%;
  height: 100%;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: flex-start;
  padding-top: 20vh;
  animation: fadeIn 1s ease-in;
}

.logo {
  width: clamp(80px, 10vw, 120px);
  margin-bottom: 30px;
	}

.link-container {
  display: none;
  gap: 20px;
  margin-top: 20px;
  flex-wrap: wrap;
  justify-content: center;
}

a.button-link {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 180px;
  height: 60px;
  text-decoration: none;
  /*background-color: rgba(255, 255, 255, 0.75);*/
  background: linear-gradient(135deg, #CC7722, #FFA500, #FAC898, #FFE5B4, #FFF5EE);
  color: black;
  border-radius: 15px;
  font-size: 18px;
  font-weight: bold;
  /*transition: background-color 0.3s ease;*/
}

a.button-link:hover {
  /*transform: scale(1.05);
  transition: transform 0.3s ease;*/
  background: linear-gradient(135deg, #FFF5EE, #FFE5B4, #FAC898, #FFA500, #CC7722);
}

a.button-link:active {
  color: grey;
}
    
footer {

  position: fixed;
  bottom: 0;
  left: 0;
  width: 100%;
  background-color: transparent;
  display: flex;
  flex-direction: column;
  align-items: center;
  padding: 10px 0;
  box-sizing: border-box;
  z-index: 1000;
  gap: 10px;
  animation: fadeIn 1s ease-in;
}

.footer-top {
  display: flex;
  flex-direction: row; /* ensures horizontal layout */
  gap: 30px;
  justify-content: center;
  align-items: center;
  flex-wrap: wrap;
}

.footer-top a {
  color: white;
  transition: color 0.3s ease;
  text-decoration: none;
  display: flex;
  align-items: center;
  gap: 8px;
}

.footer-top a:hover {
  color: #F4BB44;
  transform: scale(1.25);
  transition: transform 0.5s ease;
}

.footer-top i {
  margin: 0 5px;
}

.zalo-link {
  background-color: white;
  display: flex;
  align-items: center;
  justify-content: center;
  width: 32px;   /* same as fa-2x */
  height: 32px;
  border-radius: 6px;      /* rounded background like a button */
  transition: background-color 0.3s ease, transform 0.3s ease;
}

.zalo-icon {
  width: 100%;
  height: auto;
  display: block;
}

.zalo-link:hover {
  background-color: #F4BB44;
}

.footer-text {
  font-size: 12px;
  color: white;
  text-align: center;
}

@keyframes fadeIn {
  from { opacity: 0; transform: translateY(20px); }
  to { opacity: 1; transform: translateY(0); }
}

@media (max-width: 600px) {
  .link-container {
    flex-direction: column;
    gap: 15px;
  }

  a.button-link {
    width: 100%;
    max-width: 90vw;
    height: 50px;
  }

  footer {
    flex-wrap: wrap;
    gap: 15px;
    padding: 10px 0;
  }
}