/* Optimized CSS - ลดความซ้ำซ้อนและปรับปรุงประสิทธิภาพ */
:root {
  --primary-gradient: linear-gradient(135deg, #6a11cb 0%, #2575fc 100%);
  --dark-gradient: linear-gradient(135deg, #3a0ca3 0%, #4361ee 100%);
  --shadow-light: 0 4px 20px rgba(0, 0, 0, 0.08);
  --shadow-hover: 0 10px 25px rgba(0, 0, 0, 0.12);
  --transition: all 0.3s ease;
}

/* Base Styles */
body {
  font-family: 'Sarabun', sans-serif;
  background-color: #f0f2f5;
  transition: background-color 0.3s ease, color 0.3s ease;
  min-height: 100vh;
  margin: 0;
}

/* Layout Optimizations */
.container {
  will-change: transform;
}

.card {
  border-radius: 1rem;
  transition: var(--transition);
  box-shadow: var(--shadow-light);
  overflow: hidden;
  will-change: transform;
}

.card:hover {
  transform: translateY(-5px);
  box-shadow: var(--shadow-hover);
}

.card-header {
  border-top-left-radius: 1rem;
  border-top-right-radius: 1rem;
  background: var(--primary-gradient);
  color: white;
  font-weight: 600;
}

/* Drop Zone Optimizations */
#drop-zone {
  cursor: pointer;
  transition: var(--transition), transform 0.2s ease;
  border-style: dashed !important;
  background-color: #f8f9fa;
  position: relative;
  overflow: hidden;
  contain: layout style paint;
}

#drop-zone::before {
  content: '';
  position: absolute;
  top: 0;
  left: -100%;
  width: 100%;
  height: 100%;
  background: linear-gradient(90deg, transparent, rgba(255,255,255,0.2), transparent);
  transition: 0.5s;
}

#drop-zone:hover::before {
  left: 100%;
}

#drop-zone.dragover {
  background-color: #e9ecef;
  border-color: #0d6efd !important;
  transform: scale(1.02);
}

/* Button Optimizations */
.btn {
  transition: var(--transition);
  font-weight: 500;
  position: relative;
  overflow: hidden;
  z-index: 1;
  border: none;
  contain: layout style;
}

.btn::after {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background: rgba(255,255,255,0.1);
  transform: scaleX(0);
  transform-origin: right;
  transition: transform 0.3s ease;
  z-index: -1;
}

.btn:hover::after {
  transform: scaleX(1);
  transform-origin: left;
}

/* List Optimizations */
.list-group-item {
  background-color: #fff;
  border: 1px solid #dee2e6;
  margin-bottom: -1px;
  transition: var(--transition);
  contain: layout style;
}

.list-group-item:hover {
  background-color: #f8f9fa;
  transform: translateX(5px);
}

/* Modal Optimizations */
.modal-content {
  border-radius: 1rem;
  border: none;
  box-shadow: var(--shadow-hover);
}

.modal-header {
  border-bottom: 1px solid #dee2e6;
  background: var(--primary-gradient);
  color: white;
  border-top-left-radius: 1rem;
  border-top-right-radius: 1rem;
}

.modal-title {
  font-weight: 600;
}

/* Animation Optimizations */
@keyframes fadeInDown {
  from {
    opacity: 0;
    transform: translateY(-20px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

@keyframes pulse {
  0% { transform: scale(1); }
  50% { transform: scale(1.05); }
  100% { transform: scale(1); }
}

@keyframes spin {
  to { transform: rotate(360deg); }
}

.btn-primary {
  animation: pulse 2s infinite;
}

.btn-primary:hover {
  animation: none;
}

/* Progress Bar Optimizations */
.progress {
  border-radius: 10px;
  overflow: hidden;
  background-color: #e9ecef;
  contain: layout;
}

.progress-bar {
  transition: width 0.3s ease;
  will-change: width;
}

/* Dark Mode Optimizations */
body.dark-mode {
  background-color: #121212;
  color: #e0e0e0;
}

body.dark-mode .card {
  background-color: #1e1e1e;
  border-color: #333;
  box-shadow: 0 4px 20px rgba(0, 0, 0, 0.3);
}

body.dark-mode .card-header {
  background: var(--dark-gradient) !important;
}

body.dark-mode .modal-content {
  background-color: #1e1e1e;
  color: #e0e0e0;
}

body.dark-mode .modal-header {
  background: var(--dark-gradient) !important;
  border-bottom-color: #333;
}

body.dark-mode .form-control {
  background-color: #2a2a2a;
  color: #e0e0e0;
  border-color: #555;
}

body.dark-mode .form-control:focus {
  background-color: #333;
  color: #ffffff;
  border-color: #4dabf7;
}

/* Performance Optimizations */
#file-list li,
#result-area .d-flex {
  will-change: transform, opacity;
  contain: layout style;
}

/* Reduced Motion Support */
@media (prefers-reduced-motion: reduce) {
  *,
  *::before,
  *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
  }
  
  .btn-primary {
    animation: none;
  }
}

/* Mobile Optimizations */
@media (max-width: 768px) {
  .card {
    border-radius: 0.75rem;
    margin: 0.5rem;
  }
  
  .card-body {
    padding: 1rem !important;
  }
  
  #drop-zone {
    padding: 1.5rem !important;
  }
  
  .btn-lg {
    padding: 0.75rem 1rem;
    font-size: 1rem;
  }
  
  .modal-dialog {
    margin: 0.5rem;
  }
}

/* High DPI Display Optimizations */
@media (-webkit-min-device-pixel-ratio: 2), (min-resolution: 192dpi) {
  .card {
    border-width: 0.5px;
  }
}

/* Print Styles */
@media print {
  .btn,
  #toggle-dark-mode,
  #drop-zone {
    display: none !important;
  }
  
  .card {
    box-shadow: none !important;
    border: 1px solid #000 !important;
  }
}

/* Dark Mode Styles (เหลือเฉพาะส่วนที่จำเป็น) */
body.dark-mode #drop-zone { background-color: #2a2a2a; border-color: #555; color: #ccc; }
body.dark-mode #drop-zone.dragover { background-color: #333; border-color: #4dabf7 !important; }
body.dark-mode .list-group-item { background-color: #2c2c2c; color: #e0e0e0; border-color: #444; }
body.dark-mode .list-group-item:hover { background-color: #383838; color: #ffffff; }
body.dark-mode .form-control, body.dark-mode .form-select { background-color: #2a2a2a; color: #e0e0e0; border-color: #555; }
body.dark-mode .form-control:focus, body.dark-mode .form-select:focus { background-color: #333; color: #ffffff; border-color: #4dabf7; }
body.dark-mode .btn-primary { background-color: #0d6efd; border-color: #0d6efd; }
body.dark-mode .btn-primary:hover { background-color: #1a7eff; border-color: #1a7eff; }
body.dark-mode .btn-secondary { background-color: #3a3a3a; color: #eee; border-color: #555; }
body.dark-mode .btn-outline-secondary { color: #ccc; border-color: #555; }
body.dark-mode .btn-outline-secondary:hover { background-color: #3a3a3a; color: #fff; }
body.dark-mode .text-muted { color: #888 !important; }