body {
  font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
  background: linear-gradient(135deg, #667eea 0%, #764ba2 25%, #f093fb 50%, #f5576c 75%, #4facfe 100%);
  background-size: 400% 400%;
  animation: gradientShift 12s ease infinite;
  min-height: 100vh;
  margin: 0;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  padding: 20px;
  box-sizing: border-box;
  position: relative;
  overflow-x: hidden;
}

body::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background: 
    radial-gradient(circle at 20% 80%, rgba(120, 119, 198, 0.3) 0%, transparent 50%),
    radial-gradient(circle at 80% 20%, rgba(255, 119, 198, 0.3) 0%, transparent 50%),
    radial-gradient(circle at 40% 40%, rgba(120, 219, 255, 0.2) 0%, transparent 50%);
  pointer-events: none;
  z-index: -1;
}

@keyframes gradientShift {
  0% {
    background-position: 0% 50%;
  }
  50% {
    background-position: 100% 50%;
  }
  100% {
    background-position: 0% 50%;
  }
}

h1 {
  font-size: clamp(2.5em, 8vw, 4em);
  color: #fff;
  margin-bottom: 0.3em;
  text-shadow: 0 4px 20px rgba(0, 0, 0, 0.3), 0 0 40px rgba(255, 255, 255, 0.1);
  font-weight: 800;
  letter-spacing: -0.02em;
  text-align: center;
  background: linear-gradient(135deg, #fff 0%, #f0f0f0 100%);
  -webkit-background-clip: text;
  background-clip: text;
  -webkit-text-fill-color: transparent;
  animation: titleGlow 3s ease-in-out infinite alternate;
}

@keyframes titleGlow {
  from {
    text-shadow: 0 4px 20px rgba(0, 0, 0, 0.3), 0 0 40px rgba(255, 255, 255, 0.1);
  }
  to {
    text-shadow: 0 4px 30px rgba(0, 0, 0, 0.4), 0 0 60px rgba(255, 255, 255, 0.2);
  }
}

#payment-buttons {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: 20px;
  max-width: 900px;
  width: 100%;
  margin: 30px auto;
  perspective: 1000px;
  justify-items: center;
}

.pay-btn {
  background: linear-gradient(145deg, #ffffff, #f0f0f0);
  color: #333;
  border: none;
  border-radius: 20px;
  font-size: 1.1em;
  padding: 20px 30px;
  box-shadow: 
    0 8px 32px rgba(0, 0, 0, 0.1),
    0 2px 8px rgba(0, 0, 0, 0.1),
    inset 0 1px 0 rgba(255, 255, 255, 0.8);
  cursor: pointer;
  transition: all 0.4s cubic-bezier(0.175, 0.885, 0.32, 1.275);
  font-weight: 600;
  text-decoration: none;
  display: block;
  text-align: center;
  position: relative;
  overflow: hidden;
  backdrop-filter: blur(10px);
  border: 1px solid rgba(255, 255, 255, 0.3);
}

.pay-btn::before {
  content: '';
  position: absolute;
  top: 0;
  left: -100%;
  width: 100%;
  height: 100%;
  background: linear-gradient(90deg, transparent, rgba(255, 255, 255, 0.4), transparent);
  transition: left 0.5s;
}

.pay-btn:hover::before {
  left: 100%;
}

.pay-btn:hover {
  transform: translateY(-8px) scale(1.02);
  box-shadow: 
    0 20px 60px rgba(0, 0, 0, 0.2),
    0 8px 20px rgba(0, 0, 0, 0.15),
    inset 0 1px 0 rgba(255, 255, 255, 0.9);
  background: linear-gradient(145deg, #fff, #f8f8f8);
}

.pay-btn:active {
  transform: translateY(-4px) scale(0.98);
}

.pay-btn.premium {
  background: linear-gradient(145deg, #ffd700, #ffed4a, #ffd700);
  background-size: 200% 200%;
  animation: goldShimmer 3s ease-in-out infinite;
  color: #8b4513;
  font-size: 1.1em;
  box-shadow: 
    0 8px 32px rgba(255, 215, 0, 0.3),
    0 2px 8px rgba(255, 215, 0, 0.2),
    inset 0 1px 0 rgba(255, 255, 255, 0.8);
}

.pay-btn.premium:hover {
  background: linear-gradient(145deg, #ffed4a, #ffd700, #ffed4a);
  color: #654321;
  transform: translateY(-10px) scale(1.05);
  box-shadow: 
    0 25px 80px rgba(255, 215, 0, 0.4),
    0 10px 30px rgba(255, 215, 0, 0.3);
}

.pay-btn.retirement {
  background: linear-gradient(145deg, #ff6b35, #f7931e, #ff1744);
  background-size: 200% 200%;
  color: #fff;
  font-size: 1em;
  animation: fireGlow 2s ease-in-out infinite, gradientMove 4s ease infinite;
  text-shadow: 0 2px 4px rgba(0, 0, 0, 0.3);
  box-shadow: 
    0 8px 32px rgba(255, 107, 53, 0.4),
    0 2px 8px rgba(255, 107, 53, 0.3),
    inset 0 1px 0 rgba(255, 255, 255, 0.2);
}

.pay-btn.retirement:hover {
  background: linear-gradient(145deg, #f7931e, #ff6b35, #ff1744);
  transform: translateY(-12px) scale(1.08);
  animation: fireGlow 1s ease-in-out infinite, gradientMove 2s ease infinite;
  box-shadow: 
    0 30px 100px rgba(255, 107, 53, 0.5),
    0 15px 40px rgba(255, 107, 53, 0.4);
}

@keyframes goldShimmer {
  0%, 100% { background-position: 0% 50%; }
  50% { background-position: 100% 50%; }
}

@keyframes fireGlow {
  0%, 100% { 
    box-shadow: 
      0 8px 32px rgba(255, 107, 53, 0.4),
      0 2px 8px rgba(255, 107, 53, 0.3),
      inset 0 1px 0 rgba(255, 255, 255, 0.2);
  }
  50% { 
    box-shadow: 
      0 12px 48px rgba(255, 107, 53, 0.6),
      0 4px 12px rgba(255, 107, 53, 0.5),
      inset 0 1px 0 rgba(255, 255, 255, 0.3);
  }
}

@keyframes gradientMove {
  0% { background-position: 0% 50%; }
  50% { background-position: 100% 50%; }
  100% { background-position: 0% 50%; }
}

.subtitle {
  display: block;
  font-size: 0.75em;
  opacity: 0.85;
  font-weight: 400;
  margin-top: 5px;
  font-style: italic;
}

@keyframes pulse {
  0% { box-shadow: 0 4px 24px rgba(255, 107, 53, 0.3); }
  50% { box-shadow: 0 8px 40px rgba(255, 107, 53, 0.6); }
  100% { box-shadow: 0 4px 24px rgba(255, 107, 53, 0.3); }
}

#dollar {
  font-size: clamp(4em, 12vw, 8em);
  animation: floatAndSpin 4s ease-in-out infinite;
  color: #fff;
  margin-bottom: 0.5em;
  filter: drop-shadow(0 10px 20px rgba(0, 0, 0, 0.3));
}

@keyframes floatAndSpin {
  0%, 100% {
    transform: translateY(0px) rotate(0deg);
  }
  25% {
    transform: translateY(-20px) rotate(5deg);
  }
  50% {
    transform: translateY(-30px) rotate(0deg);
  }
  75% {
    transform: translateY(-20px) rotate(-5deg);
  }
}

/* Responsive Design */
@media (max-width: 768px) {
  #payment-buttons {
    grid-template-columns: 1fr;
    gap: 15px;
    margin: 20px 10px;
  }
  
  .pay-btn {
    padding: 18px 25px;
    font-size: 1em;
  }
  
  #message {
    padding: 15px 20px;
    margin-bottom: 2em;
  }
}

@media (max-width: 480px) {
  body {
    padding: 10px;
  }
  
  .pay-btn {
    padding: 15px 20px;
    font-size: 0.9em;
  }
}

#message {
  color: rgba(255, 255, 255, 0.95);
  font-size: clamp(1em, 3vw, 1.3em);
  margin-bottom: 3em;
  text-align: center;
  line-height: 1.6;
  max-width: 600px;
  text-shadow: 0 2px 10px rgba(0, 0, 0, 0.2);
  font-weight: 400;
  backdrop-filter: blur(10px);
  background: rgba(255, 255, 255, 0.1);
  padding: 20px 30px;
  border-radius: 20px;
  border: 1px solid rgba(255, 255, 255, 0.2);
}

#feedback {
  margin-top: 2em;
  color: rgba(255, 255, 255, 0.9);
  font-size: 1.1em;
  text-align: center;
  padding: 15px;
  border-radius: 10px;
  backdrop-filter: blur(10px);
  background: rgba(255, 255, 255, 0.1);
  border: 1px solid rgba(255, 255, 255, 0.2);
  max-width: 400px;
}