body {
  font-family: 'Segoe UI', Arial, sans-serif;
  margin: 0;
  padding: 20px;
  min-height: 100vh;
  background: linear-gradient(135deg, #ff7eb3, #ff758c, #ffb199, #6dd5ed, #2193b0);
  background-size: 300% 300%;
  animation: gradientBG 10s ease infinite;
  display: flex;
  align-items: center;
  justify-content: center;
}

.content-box {
  width: 100%;
  max-width: 850px;
  background: rgba(255, 255, 255, 0.95);
  backdrop-filter: blur(10px);
  padding: 35px;
  border-radius: 15px;
  box-shadow: 0 8px 25px rgba(0, 0, 0, 0.15);
  animation: fadeIn 0.6s ease-in-out;
}

h2 {
  color: #222;
  text-align: center;
  margin-bottom: 25px;
  font-size: 28px;
  font-weight: 600;
}

label {
  display: block;
  margin-bottom: 10px;
  font-weight: 600;
  color: #333;
}

select,
input[type="file"] {
  width: 100%;
  padding: 12px;
  margin-bottom: 18px;
  border: 2px solid #ddd;
  border-radius: 8px;
  font-size: 16px;
  transition: all 0.3s ease;
}

select:focus,
input[type="file"]:focus {
  border-color: #2193b0;
  outline: none;
  box-shadow: 0 0 6px rgba(33, 147, 176, 0.4);
}

.buttons-container {
  display: flex;
  justify-content: center;
  flex-wrap: wrap;
  gap: 12px;
}

button {
  background: linear-gradient(90deg, #2193b0, #6dd5ed);
  color: white;
  padding: 12px 28px;
  border: none;
  border-radius: 8px;
  cursor: pointer;
  font-size: 16px;
  font-weight: 600;
  transition: all 0.3s ease;
  flex-shrink: 0;
}

button:hover:not(:disabled) {
  transform: translateY(-2px);
  box-shadow: 0 4px 12px rgba(33, 147, 176, 0.3);
}

button:disabled {
  background: #9da7ac;
  cursor: not-allowed;
}

#tip {
  background-color: #e7f3ff;
  border: 1px solid #b3d9ff;
  padding: 12px;
  border-radius: 6px;
  margin: 15px 0;
  color: #0066cc;
  font-size: 15px;
  animation: fadeIn 0.4s ease-in-out;
}

#previews {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(250px, 1fr));
  gap: 18px;
  margin: 20px 0;
}

.preview-container {
  border: 1px solid #ddd;
  border-radius: 10px;
  padding: 15px;
  background-color: #fff;
  text-align: center;
  transition: all 0.3s ease;
}

.preview-container:hover {
  transform: scale(1.02);
  box-shadow: 0 6px 18px rgba(0, 0, 0, 0.1);
}

.compressed-preview {
  max-width: 100%;
  max-height: 200px;
  border-radius: 6px;
  margin-bottom: 10px;
}

.image-info {
  font-size: 14px;
  color: #666;
}

.image-info p {
  margin: 5px 0;
}

.image-info strong {
  color: #333;
}

@media (max-width: 768px) {
  .content-box {
    padding: 25px;
  }
  h2 {
    font-size: 24px;
  }
}

@media (max-width: 500px) {
  body {
    padding: 10px;
  }
  h2 {
    font-size: 20px;
  }
  button {
    width: 100%;
  }
  .buttons-container {
    flex-direction: column;
  }
}

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

@keyframes fadeIn {
  from {
    opacity: 0;
    transform: translateY(10px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}