:root {
  --bg-primary: #0d1117;
  --bg-secondary: #161b22;
  --text-primary: #c9d1d9;
  --text-secondary: #8b949e;
  --accent: #5e72e4;
  --accent-hover: #4a5fc1;
  --link: #58a6ff;
  --border: #30363d;
  --border-hover: #484f58;
  --shadow: 0 4px 12px rgba(1, 4, 9, 0.8);
  --radius-sm: 4px;
  --radius-md: 6px;
  --radius-lg: 8px;
  --transition: all 0.2s cubic-bezier(0.3, 0, 0.5, 1);
  --success: #238636;
  --error: #f85149;
  --warning: #d29922;
}

* {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

body {
  font-family: 'Inter', -apple-system, BlinkMacSystemFont, sans-serif;
  line-height: 1.6;
  color: var(--text-primary);
  background-color: var(--bg-primary);
  min-height: 100vh;
  padding: 2rem;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

.container {
  max-width: 600px;
  margin: 0 auto;
}

.card {
  background: var(--bg-secondary);
  border-radius: var(--radius-md);
  box-shadow: var(--shadow);
  border: 1px solid var(--border);
  padding: 2rem;
  margin-bottom: 2rem;
  transition: var(--transition);
}

h1 {
  color: var(--text-primary);
  text-align: center;
  margin-bottom: 1rem;
  font-weight: 600;
  font-size: 1.8rem;
}

.subtitle {
  text-align: center;
  color: var(--text-secondary);
  margin-bottom: 1.5rem;
  font-size: 1rem;
}

.upload-area {
  border: 2px dashed var(--border);
  border-radius: var(--radius-md);
  padding: 2.5rem 1rem;
  text-align: center;
  margin-bottom: 1.5rem;
  cursor: pointer;
  transition: var(--transition);
  position: relative;
  overflow: hidden;
}

.upload-area:hover, .upload-area:focus {
  border-color: var(--accent);
  background: rgba(94, 114, 228, 0.05);
  outline: none;
}

.upload-area i {
  font-size: 2.5rem;
  color: var(--accent);
  margin-bottom: 1rem;
}

.upload-area h3 {
  margin-bottom: 0.5rem;
  font-weight: 600;
  color: var(--text-primary);
}

.upload-area p {
  color: var(--text-secondary);
  font-size: 0.9rem;
}

#file-name {
  margin-top: 1rem;
  font-size: 0.9rem;
  color: var(--accent);
  font-weight: 500;
  word-break: break-all;
}

#file-size {
  font-size: 0.8rem;
  color: var(--text-secondary);
  margin-top: 0.25rem;
}

.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border-width: 0;
}

input[type="file"] {
  display: none;
}

.input-group {
  display: flex;
  margin-bottom: 1.5rem;
  align-items: center;
  gap: 0.5rem;
}

.input-group label {
  color: var(--text-secondary);
  font-size: 0.9rem;
  min-width: 120px;
}

.input-group input, .input-group select {
  flex: 1;
  padding: 0.75rem 1rem;
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  font-size: 1rem;
  transition: var(--transition);
  background-color: var(--bg-primary);
  color: var(--text-primary);
}

.input-group input:focus, .input-group select:focus {
  outline: none;
  border-color: var(--accent);
  box-shadow: 0 0 0 3px rgba(94, 114, 228, 0.3);
}

.btn {
  background: var(--accent);
  color: white;
  border: none;
  padding: 0.75rem 1.5rem;
  border-radius: var(--radius-sm);
  font-size: 1rem;
  font-weight: 500;
  cursor: pointer;
  transition: var(--transition);
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
  width: 100%;
}

.btn:hover {
  background: var(--accent-hover);
  transform: translateY(-1px);
  text-decoration: none;
}

.btn:active {
  transform: translateY(0);
}

.btn:disabled {
  opacity: 0.6;
  cursor: not-allowed;
  transform: none;
}

.btn-secondary {
  background: var(--bg-secondary);
  color: var(--accent);
  border: 1px solid var(--accent);
  margin-top: 1rem;
}

.btn-secondary:hover:not(:disabled) {
  background: rgba(94, 114, 228, 0.1);
}

#result {
  margin-top: 1.5rem;
  padding: 1rem;
  border-radius: var(--radius-sm);
  font-weight: 500;
  text-align: center;
  display: none;
  border: 1px solid transparent;
}

.progress-container {
  margin: 1.5rem 0;
  display: none;
}

.progress-bar {
  height: 6px;
  background: var(--border);
  border-radius: 3px;
  overflow: hidden;
}

.progress {
  height: 100%;
  background: var(--accent);
  width: 0%;
  transition: width 0.3s ease;
}

.progress-text {
  text-align: center;
  font-size: 0.85rem;
  color: var(--text-secondary);
  margin-top: 0.5rem;
}

.comparison-container {
  display: none;
  justify-content: space-between;
  margin: 1.5rem 0;
  gap: 1rem;
}

.image-comparison {
  flex: 1;
  text-align: center;
}

.image-comparison img {
  max-width: 100%;
  max-height: 300px;
  object-fit: contain;
  border-radius: var(--radius-sm);
  border: 1px solid var(--border);
  background-color: var(--bg-primary);
}

.image-comparison h4 {
  margin: 0.5rem 0;
  font-weight: 600;
  color: var(--text-primary);
}

.image-comparison .size-info {
  font-size: 0.85rem;
  color: var(--text-secondary);
}

.size-warning {
  color: var(--warning);
  font-size: 0.8rem;
  margin-top: -1rem;
  margin-bottom: 1rem;
  display: none;
}

.error-message {
  color: var(--error);
  font-size: 0.9rem;
  margin-top: 0.5rem;
  display: none;
}

.fa-spin {
  animation: fa-spin 1s infinite linear;
}

@keyframes fa-spin {
  0% { transform: rotate(0deg); }
  100% { transform: rotate(360deg); }
}

[aria-busy="true"] {
  cursor: progress;
}

@media (max-width: 768px) {
  body {
    padding: 1.5rem;
  }
  
  .card {
    padding: 1.5rem;
  }
  
  .comparison-container {
    flex-direction: column;
  }
  
  h1 {
    font-size: 1.5rem;
  }
  
  .input-group {
    flex-direction: column;
    align-items: flex-start;
    gap: 0.5rem;
  }
  
  .input-group label {
    margin-bottom: 0;
    min-width: auto;
    width: 100%;
  }
}