/* 디자인 시스템 토큰 정의 */
:root {
  /* 테마별 공통 변수 (애니메이션, 글꼴 등) */
  --font-sans: 'Inter', 'Noto Sans KR', -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
  --transition-fast: 0.15s ease;
  --transition-normal: 0.25s ease;
  --radius-sm: 6px;
  --radius-md: 10px;
  --radius-lg: 16px;
  --shadow-sm: 0 1px 3px rgba(0, 0, 0, 0.1);
  --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -1px rgba(0, 0, 0, 0.06);
  --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1), 0 4px 6px -2px rgba(0, 0, 0, 0.05);
  --shadow-glow: 0 0 15px rgba(99, 102, 241, 0.35);
}

/* 어두운 테마 (기본) */
html[data-theme="dark"] {
  --bg-app: #0f172a;
  --bg-card: #1e293b;
  --bg-input: #0f172a;
  --bg-empty: #1a2333;
  --text-primary: #f8fafc;
  --text-secondary: #94a3b8;
  --text-muted: #64748b;
  --border-color: #334155;
  --border-focus: #6366f1;
  --primary: #6366f1;
  --primary-hover: #4f46e5;
  --primary-rgb: 99, 102, 241;
  --success: #10b981;
  --success-hover: #059669;
  --danger: #ef4444;
  --danger-hover: #dc2626;
  --checker-color-1: #1e293b;
  --checker-color-2: #2d3d52;
  --preview-bg-dark: #090d16;
  --preview-bg-light: #f1f5f9;
}

/* 밝은 테마 */
html[data-theme="light"] {
  --bg-app: #f8fafc;
  --bg-card: #ffffff;
  --bg-input: #f1f5f9;
  --bg-empty: #f8fafc;
  --text-primary: #0f172a;
  --text-secondary: #475569;
  --text-muted: #64748b;
  --border-color: #e2e8f0;
  --border-focus: #4f46e5;
  --primary: #4f46e5;
  --primary-hover: #4338ca;
  --primary-rgb: 79, 70, 229;
  --success: #10b981;
  --success-hover: #059669;
  --danger: #ef4444;
  --danger-hover: #dc2626;
  --checker-color-1: #e2e8f0;
  --checker-color-2: #ffffff;
  --preview-bg-dark: #0f172a;
  --preview-bg-light: #ffffff;
}

/* 초기화 & 기본 스타일 */
* {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

body {
  font-family: var(--font-sans);
  background-color: var(--bg-app);
  color: var(--text-primary);
  line-height: 1.6;
  transition: background-color var(--transition-normal), color var(--transition-normal);
  min-height: 100vh;
}

.app-container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 24px 16px;
  display: flex;
  flex-direction: column;
  min-height: 100vh;
}

/* 헤더 스타일 */
.app-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 24px;
  padding-bottom: 16px;
  border-bottom: 1px solid var(--border-color);
}

.logo-group {
  display: flex;
  align-items: center;
  gap: 12px;
}

.logo-icon {
  width: 44px;
  height: 44px;
  background: linear-gradient(135deg, var(--primary), #3b82f6);
  border-radius: var(--radius-md);
  display: flex;
  align-items: center;
  justify-content: center;
  color: white;
  box-shadow: 0 4px 10px rgba(99, 102, 241, 0.3);
}

.logo-icon svg {
  width: 24px;
  height: 24px;
}

.logo-text h1 {
  font-size: 1.25rem;
  font-weight: 700;
  letter-spacing: -0.025em;
  color: var(--text-primary);
}

.logo-text p {
  font-size: 0.85rem;
  color: var(--text-secondary);
}

/* 아이콘 버튼 공통 */
.icon-btn {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  color: var(--text-primary);
  width: 40px;
  height: 40px;
  border-radius: var(--radius-md);
  display: flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  transition: all var(--transition-fast);
}

.icon-btn:hover {
  border-color: var(--primary);
  color: var(--primary);
  transform: translateY(-2px);
  box-shadow: var(--shadow-sm);
}

.icon-btn svg {
  width: 20px;
  height: 20px;
}

/* 테마 전환용 아이콘 표시 분기 */
html[data-theme="dark"] .sun-icon { display: block; }
html[data-theme="dark"] .moon-icon { display: none; }
html[data-theme="light"] .sun-icon { display: none; }
html[data-theme="light"] .moon-icon { display: block; }

/* 레이아웃 그리드 */
.layout-grid {
  display: grid;
  grid-template-columns: 1.1fr 1fr;
  gap: 24px;
  flex: 1;
}

.config-panel, .preview-panel {
  display: flex;
  flex-direction: column;
  gap: 24px;
}

/* 카드 공통 스타일 */
.card {
  background-color: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  padding: 24px;
  box-shadow: var(--shadow-sm);
  transition: background-color var(--transition-normal), border-color var(--transition-normal);
}

.card-title {
  font-size: 1.05rem;
  font-weight: 600;
  margin-bottom: 16px;
  color: var(--text-primary);
  display: flex;
  align-items: center;
  gap: 8px;
}

.card-header-flex {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 16px;
}

.card-header-flex .card-title {
  margin-bottom: 0;
}

/* 드롭존 영역 */
.drop-zone {
  border: 2px dashed var(--border-color);
  border-radius: var(--radius-md);
  padding: 32px 16px;
  text-align: center;
  cursor: pointer;
  background-color: var(--bg-input);
  transition: all var(--transition-normal);
  position: relative;
  overflow: hidden;
}

.drop-zone:hover, .drop-zone.dragover {
  border-color: var(--primary);
  box-shadow: var(--shadow-glow);
  background-color: rgba(99, 102, 241, 0.03);
}

.drop-zone-content {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 12px;
}

.upload-icon {
  width: 48px;
  height: 48px;
  color: var(--text-secondary);
  transition: color var(--transition-fast), transform var(--transition-normal);
}

.drop-zone:hover .upload-icon, .drop-zone.dragover .upload-icon {
  color: var(--primary);
  transform: translateY(-4px);
}

.upload-icon svg {
  width: 100%;
  height: 100%;
}

.upload-text {
  font-weight: 500;
  font-size: 0.95rem;
  color: var(--text-primary);
}

.upload-subtext {
  font-size: 0.8rem;
  color: var(--text-muted);
}

/* 파일 로딩 상태 표시 정보 */
.file-info-container {
  display: flex;
  align-items: center;
  gap: 12px;
  margin-top: 16px;
  padding: 12px;
  background-color: var(--bg-input);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  animation: fadeIn var(--transition-normal);
}

.file-info-container.hidden {
  display: none !important;
}

.file-preview-mini {
  width: 48px;
  height: 48px;
  border-radius: var(--radius-sm);
  background-size: contain;
  background-repeat: no-repeat;
  background-position: center;
  background-color: transparent;
  border: 1px solid var(--border-color);
  background-image: 
    linear-gradient(45deg, var(--checker-color-1) 25%, transparent 25%), 
    linear-gradient(-45deg, var(--checker-color-1) 25%, transparent 25%), 
    linear-gradient(45deg, transparent 75%, var(--checker-color-1) 75%), 
    linear-gradient(-45deg, transparent 75%, var(--checker-color-1) 75%);
  background-size: 8px 8px;
  background-position: 0 0, 0 4px, 4px -4px, -4px 0px;
}

.file-details {
  flex: 1;
  min-width: 0; /* 텍스트 생략 기능을 위해 필요 */
}

.file-name {
  font-size: 0.9rem;
  font-weight: 600;
  color: var(--text-primary);
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

.file-meta {
  font-size: 0.75rem;
  color: var(--text-secondary);
}

.clear-btn {
  background: transparent;
  border: none;
  color: var(--text-muted);
  cursor: pointer;
  padding: 4px;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: all var(--transition-fast);
}

.clear-btn:hover {
  background-color: rgba(239, 68, 68, 0.1);
  color: var(--danger);
}

.clear-btn svg {
  width: 18px;
  height: 18px;
}

/* 프리셋 선택 버튼 그룹 */
.preset-buttons {
  display: flex;
  gap: 8px;
  margin-bottom: 16px;
  flex-wrap: wrap;
}

.preset-btn {
  background: var(--bg-input);
  border: 1px solid var(--border-color);
  color: var(--text-secondary);
  padding: 6px 12px;
  border-radius: var(--radius-sm);
  font-size: 0.8rem;
  font-weight: 500;
  cursor: pointer;
  transition: all var(--transition-fast);
}

.preset-btn:hover {
  border-color: var(--text-secondary);
  color: var(--text-primary);
}

.preset-btn.active {
  background-color: rgba(99, 102, 241, 0.1);
  border-color: var(--primary);
  color: var(--primary);
}

/* 아이콘 크기 체크박스 그리드 */
.sizes-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 12px;
  margin-bottom: 8px;
}

.size-checkbox-label {
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 12px;
  background-color: var(--bg-input);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  cursor: pointer;
  user-select: none;
  transition: all var(--transition-fast);
}

.size-checkbox-label:hover {
  border-color: var(--primary);
  transform: translateY(-1px);
}

.size-checkbox-label input[type="checkbox"] {
  display: none;
}

.checkbox-custom {
  width: 18px;
  height: 18px;
  border: 2px solid var(--text-muted);
  border-radius: 4px;
  display: inline-block;
  position: relative;
  transition: all var(--transition-fast);
  background: transparent;
  flex-shrink: 0;
}

.size-checkbox-label input[type="checkbox"]:checked + .checkbox-custom {
  background-color: var(--primary);
  border-color: var(--primary);
}

.size-checkbox-label input[type="checkbox"]:checked + .checkbox-custom::after {
  content: "";
  position: absolute;
  left: 5px;
  top: 1px;
  width: 4px;
  height: 9px;
  border: solid white;
  border-width: 0 2px 2px 0;
  transform: rotate(45deg);
}

.size-text {
  font-size: 0.85rem;
  font-weight: 500;
  color: var(--text-primary);
  display: flex;
  flex-direction: column;
  line-height: 1.2;
}

.size-text small {
  font-size: 0.7rem;
  color: var(--text-muted);
  margin-top: 2px;
}

/* 구분선 */
.section-divider {
  margin-top: 24px;
  padding-top: 16px;
  border-top: 1px solid var(--border-color);
}

/* 옵션 설정 행 */
.option-row {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 12px 0;
  border-bottom: 1px dashed var(--border-color);
  gap: 16px;
}

.option-row:last-of-type {
  border-bottom: none;
  padding-bottom: 0;
}

.option-label {
  display: flex;
  flex-direction: column;
  max-width: 65%;
}

.option-title {
  font-size: 0.9rem;
  font-weight: 500;
  color: var(--text-primary);
}

.option-desc {
  font-size: 0.75rem;
  color: var(--text-muted);
  margin-top: 2px;
}

/* 드롭다운 셀렉트 */
.select-wrapper {
  position: relative;
  width: 150px;
}

.select-wrapper select {
  width: 100%;
  padding: 8px 12px;
  background-color: var(--bg-input);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-sm);
  color: var(--text-primary);
  font-size: 0.85rem;
  outline: none;
  cursor: pointer;
  appearance: none;
  transition: all var(--transition-fast);
}

.select-wrapper select:focus {
  border-color: var(--border-focus);
  box-shadow: 0 0 0 2px rgba(var(--primary-rgb), 0.15);
}

.select-wrapper::after {
  content: "";
  position: absolute;
  right: 12px;
  top: 50%;
  transform: translateY(-50%);
  border: 5px solid transparent;
  border-top-color: var(--text-secondary);
  pointer-events: none;
}

/* 토글 스위치 */
.toggle-switch {
  position: relative;
  display: inline-block;
  width: 44px;
  height: 24px;
  flex-shrink: 0;
}

.toggle-switch input {
  opacity: 0;
  width: 0;
  height: 0;
}

.toggle-slider {
  position: absolute;
  cursor: pointer;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background-color: var(--border-color);
  transition: var(--transition-normal);
  border-radius: 24px;
}

.toggle-slider:before {
  position: absolute;
  content: "";
  height: 16px;
  width: 16px;
  left: 4px;
  bottom: 4px;
  background-color: white;
  transition: var(--transition-normal);
  border-radius: 50%;
  box-shadow: 0 1px 3px rgba(0,0,0,0.15);
}

.toggle-switch input:checked + .toggle-slider {
  background-color: var(--primary);
}

.toggle-switch input:checked + .toggle-slider:before {
  transform: translateX(20px);
}

/* 배경 채우기 도구 */
.bg-fill-container {
  display: flex;
  align-items: center;
  gap: 12px;
}

.color-picker-wrapper {
  display: flex;
  align-items: center;
  gap: 8px;
  padding: 4px 8px;
  background: var(--bg-input);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-sm);
  transition: all var(--transition-fast);
}

.color-picker-wrapper.disabled {
  opacity: 0.5;
  pointer-events: none;
}

.color-picker-wrapper input[type="color"] {
  border: none;
  background: none;
  width: 24px;
  height: 24px;
  cursor: pointer;
  appearance: none;
}

.color-picker-wrapper input[type="color"]::-webkit-color-swatch-wrapper {
  padding: 0;
}

.color-picker-wrapper input[type="color"]::-webkit-color-swatch {
  border: 1px solid var(--border-color);
  border-radius: 4px;
}

.color-value {
  font-family: monospace;
  font-size: 0.75rem;
  color: var(--text-secondary);
}

/* 미리보기 백그라운드 토글 */
.preview-bg-toggles {
  display: flex;
  gap: 6px;
}

.preview-bg-btn {
  width: 20px;
  height: 20px;
  border-radius: 50%;
  border: 2px solid var(--border-color);
  cursor: pointer;
  transition: all var(--transition-fast);
}

.preview-bg-btn.active {
  transform: scale(1.2);
  border-color: var(--primary);
}

.preview-bg-btn[data-bg="grid"] {
  background-image: 
    linear-gradient(45deg, #ccc 25%, transparent 25%), 
    linear-gradient(-45deg, #ccc 25%, transparent 25%), 
    linear-gradient(45deg, transparent 75%, #ccc 75%), 
    linear-gradient(-45deg, transparent 75%, #ccc 75%);
  background-size: 6px 6px;
  background-position: 0 0, 0 3px, 3px -3px, -3px 0px;
}

.preview-bg-btn[data-bg="dark"] {
  background-color: #0f172a;
}

.preview-bg-btn[data-bg="light"] {
  background-color: #ffffff;
}

/* 미리보기 배치 컨테이너 */
.preview-container {
  display: flex;
  flex-direction: column;
  gap: 16px;
  min-height: 250px;
  justify-content: center;
}

/* 비어있는 상태 표시 */
.empty-state {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  padding: 48px 16px;
  color: var(--text-muted);
  text-align: center;
  background-color: var(--bg-empty);
  border: 1px dashed var(--border-color);
  border-radius: var(--radius-md);
  gap: 16px;
}

.empty-icon {
  width: 64px;
  height: 64px;
  color: var(--text-muted);
}

.empty-icon svg {
  width: 100%;
  height: 100%;
}

.empty-state p {
  font-size: 0.85rem;
  max-width: 320px;
}

/* 실제 미리보기 리스트 그리드 */
.previews-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(130px, 1fr));
  gap: 16px;
}

/* 미리보기 카드 개별 아이템 */
.preview-item-card {
  background-color: var(--bg-input);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  padding: 12px;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 10px;
  position: relative;
  animation: scaleUp var(--transition-normal);
}

.preview-size-tag {
  font-size: 0.75rem;
  font-weight: 600;
  color: var(--text-secondary);
  background-color: var(--bg-card);
  padding: 2px 6px;
  border-radius: 4px;
  border: 1px solid var(--border-color);
}

/* 체커보드 배경을 가진 아이콘 뷰어 */
.preview-icon-wrapper {
  width: 100px;
  height: 100px;
  display: flex;
  align-items: center;
  justify-content: center;
  border-radius: var(--radius-sm);
  border: 1px solid var(--border-color);
  overflow: hidden;
  position: relative;
  transition: background var(--transition-normal);
}

/* 테마 배경 선택에 따른 적용 클래스 */
.preview-icon-wrapper.bg-grid {
  background-image: 
    linear-gradient(45deg, var(--checker-color-1) 25%, transparent 25%), 
    linear-gradient(-45deg, var(--checker-color-1) 25%, transparent 25%), 
    linear-gradient(45deg, transparent 75%, var(--checker-color-1) 75%), 
    linear-gradient(-45deg, transparent 75%, var(--checker-color-1) 75%);
  background-size: 10px 10px;
  background-position: 0 0, 0 5px, 5px -5px, -5px 0px;
  background-color: var(--checker-color-2);
}

.preview-icon-wrapper.bg-dark {
  background-color: var(--preview-bg-dark) !important;
  background-image: none !important;
}

.preview-icon-wrapper.bg-light {
  background-color: var(--preview-bg-light) !important;
  background-image: none !important;
}

.preview-icon-wrapper img {
  max-width: 100%;
  max-height: 100%;
  object-fit: contain;
  /* 픽셀 크기에 따라 계단현상 렌더링(크기가 작을 때 유용) */
  image-rendering: -webkit-optimize-contrast;
  image-rendering: pixelated;
}

/* 개별 다운로드 버튼 */
.item-download-btn {
  background-color: var(--bg-card);
  border: 1px solid var(--border-color);
  color: var(--text-primary);
  width: 100%;
  padding: 6px;
  border-radius: var(--radius-sm);
  font-size: 0.75rem;
  font-weight: 500;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 4px;
  transition: all var(--transition-fast);
}

.item-download-btn:hover {
  border-color: var(--primary);
  color: var(--primary);
  background-color: rgba(99, 102, 241, 0.05);
}

.item-download-btn svg {
  width: 12px;
  height: 12px;
}

/* 메인 액션 및 다운로드 영역 */
.download-action-area {
  margin-top: 24px;
  padding-top: 20px;
  border-top: 1px solid var(--border-color);
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 10px;
  animation: fadeIn var(--transition-normal);
}

.download-action-area.hidden {
  display: none !important;
}

.primary-btn {
  background-color: var(--primary);
  color: white;
  border: none;
  padding: 14px 28px;
  border-radius: var(--radius-md);
  font-weight: 600;
  font-size: 0.95rem;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  width: 100%;
  box-shadow: 0 4px 12px rgba(99, 102, 241, 0.25);
  transition: all var(--transition-fast);
}

.primary-btn:hover {
  background-color: var(--primary-hover);
  transform: translateY(-2px);
  box-shadow: 0 6px 16px rgba(99, 102, 241, 0.35);
}

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

.primary-btn svg {
  width: 20px;
  height: 20px;
}

.download-tip {
  font-size: 0.75rem;
  color: var(--text-muted);
  text-align: center;
}

/* 푸터 영역 */
.app-footer {
  margin-top: 48px;
  padding-top: 24px;
  border-top: 1px solid var(--border-color);
  text-align: center;
  font-size: 0.8rem;
  color: var(--text-muted);
  display: flex;
  flex-direction: column;
  gap: 8px;
}

.app-footer strong {
  color: var(--text-secondary);
}

.copyright {
  margin-top: 4px;
  font-size: 0.75rem;
}

/* 키프레임 애니메이션 정의 */
@keyframes fadeIn {
  from { opacity: 0; }
  to { opacity: 1; }
}

@keyframes scaleUp {
  from { opacity: 0; transform: scale(0.95); }
  to { opacity: 1; transform: scale(1); }
}

/* 모바일 인터페이스를 고려한 미디어 쿼리 (반응형 대응) */
@media (max-width: 820px) {
  .layout-grid {
    grid-template-columns: 1fr;
    gap: 20px;
  }
  
  .app-header {
    flex-direction: row;
    padding-bottom: 12px;
  }
  
  .logo-icon {
    width: 38px;
    height: 38px;
  }
  
  .logo-text h1 {
    font-size: 1.1rem;
  }
  
  .logo-text p {
    font-size: 0.75rem;
  }
  
  .card {
    padding: 16px;
  }
  
  .sizes-grid {
    grid-template-columns: 1fr;
    gap: 8px;
  }
  
  .previews-grid {
    grid-template-columns: repeat(auto-fill, minmax(110px, 1fr));
    gap: 12px;
  }
  
  .preview-icon-wrapper {
    width: 80px;
    height: 80px;
  }
}

@media (max-width: 480px) {
  body {
    padding: 0;
  }
  
  .app-container {
    padding: 12px;
  }
  
  .preset-buttons {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    width: 100%;
  }
  
  .preset-btn {
    text-align: center;
  }
  
  .option-row {
    flex-direction: column;
    align-items: flex-start;
    gap: 10px;
  }
  
  .select-wrapper {
    width: 100%;
  }
  
  .bg-fill-container {
    width: 100%;
    justify-content: space-between;
  }
}