body {
  font-family: Arial, sans-serif;
  margin: 0;
  background: linear-gradient(135deg, #07111f, #0b1220, #111827);
  color: #111;
}

nav {
  background: linear-gradient(90deg, #020617, #0f172a);
  color: white;
  padding: 25px 40px;
  box-shadow: 0 4px 20px rgba(0,0,0,0.4);
}

nav h1 {
  margin: 0;
  font-size: 34px;
  letter-spacing: 1px;
  color: #f8fafc;
}

.product {
  min-height: 85vh;
  display: flex;
  justify-content: center;
  align-items: center;
  padding: 60px 20px;
  position: relative;
}

.product::before {
  content: "";
  position: absolute;
  width: 550px;
  height: 550px;
  background: radial-gradient(circle, rgba(37,99,235,0.25), transparent 70%);
  border-radius: 50%;
  z-index: 0;
}

.productImg {
  width: 420px;
  max-width: 90%;
  filter: drop-shadow(0 25px 35px rgba(0,0,0,0.45));
  position: relative;
  z-index: 2;
}

.productDetails {
  background: rgba(255,255,255,0.96);
  padding: 35px;
  border-radius: 22px;
  margin-left: 40px;
  max-width: 420px;
  box-shadow: 0 20px 50px rgba(0,0,0,0.35);
  position: relative;
  z-index: 2;
}

.productTitle {
  font-size: 42px;
  margin: 0 0 15px;
  color: #0f172a;
}

.productPrice {
  font-size: 30px;
  color: #2563eb;
  margin-bottom: 15px;
}

.productSpecs {
  font-size: 15px;
  color: #475569;
  line-height: 1.6;
  margin-bottom: 25px;
}

.productButton {
  padding: 16px 28px;
  background: linear-gradient(90deg, #2563eb, #1d4ed8);
  color: white;
  border: none;
  border-radius: 12px;
  font-weight: bold;
  cursor: pointer;
  box-shadow: 0 8px 20px rgba(37,99,235,0.35);
  transition: 0.3s;
}

.productButton:hover {
  background: linear-gradient(90deg, #1d4ed8, #1e40af);
  transform: translateY(-2px);
}

.payment {
  width: 420px;
  max-width: 95%;
  max-height: 90vh;
  overflow-y: auto;
  background: white;
  position: fixed;
  top: 50%;
  left: 50%;
  transform: translate(-50%,-50%);
  padding: 30px;
  display: none;
  flex-direction: column;
  border-radius: 18px;
  box-shadow: 0 25px 70px rgba(0,0,0,0.55);
  z-index: 9999;
}

.payTitle {
  color: #0f172a;
  margin-top: 0;
}

label {
  font-weight: bold;
  font-size: 14px;
  color: #334155;
}

.payInput {
  padding: 12px;
  margin: 8px 0 14px;
  border: 1px solid #cbd5e1;
  border-radius: 8px;
  font-size: 15px;
}

textarea.payInput {
  min-height: 80px;
  resize: vertical;
}

.reserveNote {
  background: #eff6ff;
  border-left: 5px solid #2563eb;
  padding: 12px;
  font-size: 14px;
  border-radius: 8px;
  line-height: 1.7;
}

.payButton {
  background: linear-gradient(90deg, #0f172a, #1e293b);
  color: white;
  border: none;
  padding: 14px;
  border-radius: 10px;
  font-weight: bold;
  cursor: pointer;
  transition: 0.3s;
}

.payButton:hover {
  background: linear-gradient(90deg, #1e293b, #334155);
}

.close {
  position: absolute;
  top: 12px;
  right: 14px;
  background: #ef4444;
  color: white;
  padding: 4px 8px;
  border-radius: 50%;
  cursor: pointer;
  font-weight: bold;
}

@media screen and (max-width: 768px) {

  .product {
    flex-direction: column;
    text-align: center;
    padding: 40px 15px;
  }

  .productDetails {
    margin-left: 0;
    margin-top: 25px;
    width: 100%;
    max-width: 100%;
  }

  .productImg {
    width: 320px;
  }

  .productTitle {
    font-size: 34px;
  }

  .productPrice {
    font-size: 24px;
  }

  nav {
    padding: 20px;
  }

  nav h1 {
    font-size: 26px;
    text-align: center;
  }

  .payment {
    width: 94%;
    max-height: 88vh;
    padding: 22px;
  }

  .payTitle {
    font-size: 22px;
  }

  .payInput {
    padding: 11px;
    font-size: 14px;
  }

  .reserveNote {
    font-size: 13px;
  }

  .payButton {
    padding: 13px;
    font-size: 15px;
  }
}