/* ==================== 全局样式 ==================== */
* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

:root {
  /* 颜色系统 */
  --primary-gradient: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
  --secondary-gradient: linear-gradient(135deg, #f093fb 0%, #f5576c 100%);
  --success-gradient: linear-gradient(135deg, #4facfe 0%, #00f2fe 100%);
  
  --color-primary: #667eea;
  --color-primary-dark: #5568d3;
  --color-secondary: #764ba2;
  --color-success: #00f2fe;
  --color-error: #f5576c;
  
  /* 中性色 */
  --color-bg: #0f0f1e;
  --color-surface: #1a1a2e;
  --color-surface-hover: #242438;
  --color-border: rgba(255, 255, 255, 0.1);
  --color-text-primary: #ffffff;
  --color-text-secondary: rgba(255, 255, 255, 0.7);
  --color-text-tertiary: rgba(255, 255, 255, 0.5);
  
  /* 间距 */
  --spacing-xs: 0.5rem;
  --spacing-sm: 1rem;
  --spacing-md: 1.5rem;
  --spacing-lg: 2rem;
  --spacing-xl: 3rem;
  
  /* 圆角 */
  --radius-sm: 8px;
  --radius-md: 12px;
  --radius-lg: 16px;
  --radius-xl: 24px;
  
  /* 阴影 */
  --shadow-sm: 0 2px 8px rgba(0, 0, 0, 0.1);
  --shadow-md: 0 4px 16px rgba(0, 0, 0, 0.2);
  --shadow-lg: 0 8px 32px rgba(0, 0, 0, 0.3);
  --shadow-glow: 0 0 40px rgba(102, 126, 234, 0.3);
  
  /* 动画 */
  --transition-fast: 150ms ease;
  --transition-base: 250ms ease;
  --transition-slow: 350ms ease;
}

body {
  font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
  background: var(--color-bg);
  color: var(--color-text-primary);
  line-height: 1.6;
  min-height: 100vh;
  overflow-x: hidden;
}

body::before {
  content: '';
  position: fixed;
  top: -50%;
  left: -50%;
  width: 200%;
  height: 200%;
  background: radial-gradient(circle at 50% 50%, rgba(102, 126, 234, 0.1) 0%, transparent 50%);
  animation: rotate 60s linear infinite;
  pointer-events: none;
  z-index: 0;
}

@keyframes rotate {
  from { transform: rotate(0deg); }
  to { transform: rotate(360deg); }
}

.container {
  max-width: 1200px;
  margin: 0 auto;
  padding: var(--spacing-lg);
  position: relative;
  z-index: 1;
}

/* ==================== 头部 ==================== */
.header {
  text-align: center;
  margin-bottom: var(--spacing-xl);
  animation: fadeInDown 0.6s ease;
}

.logo {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: var(--spacing-sm);
  margin-bottom: var(--spacing-sm);
}

.logo h1 {
  font-size: 2.5rem;
  font-weight: 700;
  background: var(--primary-gradient);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.subtitle {
  font-size: 1.125rem;
  color: var(--color-text-secondary);
  font-weight: 400;
}

/* ==================== 上传区域 ==================== */
.upload-section {
  animation: fadeIn 0.6s ease 0.2s both;
}

.upload-area {
  background: var(--color-surface);
  border: 2px dashed var(--color-border);
  border-radius: var(--radius-xl);
  padding: var(--spacing-xl);
  text-align: center;
  transition: all var(--transition-base);
  cursor: pointer;
  position: relative;
  overflow: hidden;
}

.upload-area::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background: var(--primary-gradient);
  opacity: 0;
  transition: opacity var(--transition-base);
  pointer-events: none;
}

.upload-area:hover {
  border-color: var(--color-primary);
  transform: translateY(-4px);
  box-shadow: var(--shadow-glow);
}

.upload-area:hover::before {
  opacity: 0.05;
}

.upload-area.drag-over {
  border-color: var(--color-primary);
  background: rgba(102, 126, 234, 0.1);
  transform: scale(1.02);
}

.upload-icon {
  color: var(--color-primary);
  margin-bottom: var(--spacing-md);
  animation: float 3s ease-in-out infinite;
}

@keyframes float {
  0%, 100% { transform: translateY(0); }
  50% { transform: translateY(-10px); }
}

.upload-area h2 {
  font-size: 1.5rem;
  font-weight: 600;
  margin-bottom: var(--spacing-xs);
}

.upload-area p {
  color: var(--color-text-secondary);
  margin-bottom: var(--spacing-sm);
}

.file-info {
  font-size: 0.875rem;
  color: var(--color-text-tertiary);
  margin-bottom: var(--spacing-md);
}

/* ==================== 按钮 ==================== */
.btn {
  padding: 0.875rem 2rem;
  border: none;
  border-radius: var(--radius-md);
  font-size: 1rem;
  font-weight: 600;
  cursor: pointer;
  transition: all var(--transition-base);
  display: inline-flex;
  align-items: center;
  gap: var(--spacing-xs);
  position: relative;
  overflow: hidden;
  font-family: inherit;
}

.btn::before {
  content: '';
  position: absolute;
  top: 50%;
  left: 50%;
  width: 0;
  height: 0;
  border-radius: 50%;
  background: rgba(255, 255, 255, 0.2);
  transform: translate(-50%, -50%);
  transition: width 0.6s, height 0.6s;
}

.btn:hover::before {
  width: 300px;
  height: 300px;
}

.btn-primary {
  background: var(--primary-gradient);
  color: white;
  box-shadow: var(--shadow-md);
}

.btn-primary:hover {
  transform: translateY(-2px);
  box-shadow: var(--shadow-lg);
}

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

.btn-secondary {
  background: var(--color-surface);
  color: var(--color-text-primary);
  border: 1px solid var(--color-border);
}

.btn-secondary:hover {
  background: var(--color-surface-hover);
  border-color: var(--color-primary);
}

/* ==================== 处理区域 ==================== */
.processing-section {
  animation: fadeIn 0.6s ease;
}

.image-container {
  display: grid;
  grid-template-columns: 1fr auto 1fr;
  gap: var(--spacing-lg);
  margin-bottom: var(--spacing-lg);
  align-items: center;
}

.image-wrapper {
  background: var(--color-surface);
  border-radius: var(--radius-lg);
  padding: var(--spacing-md);
  box-shadow: var(--shadow-md);
  transition: transform var(--transition-base);
}

.image-wrapper:hover {
  transform: translateY(-4px);
}

.image-wrapper h3 {
  font-size: 1rem;
  font-weight: 600;
  margin-bottom: var(--spacing-sm);
  color: var(--color-text-secondary);
  text-align: center;
}

.image-wrapper img {
  width: 100%;
  height: auto;
  max-height: 400px;
  object-fit: contain;
  border-radius: var(--radius-sm);
  background: 
    linear-gradient(45deg, #2a2a3e 25%, transparent 25%),
    linear-gradient(-45deg, #2a2a3e 25%, transparent 25%),
    linear-gradient(45deg, transparent 75%, #2a2a3e 75%),
    linear-gradient(-45deg, transparent 75%, #2a2a3e 75%);
  background-size: 20px 20px;
  background-position: 0 0, 0 10px, 10px -10px, -10px 0px;
}

.arrow {
  color: var(--color-primary);
  animation: pulse 2s ease-in-out infinite;
}

@keyframes pulse {
  0%, 100% { opacity: 0.5; transform: scale(1); }
  50% { opacity: 1; transform: scale(1.1); }
}

.result-placeholder {
  width: 100%;
  height: 400px;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  background: rgba(102, 126, 234, 0.05);
  border-radius: var(--radius-sm);
  border: 2px dashed var(--color-border);
}

.loader {
  width: 48px;
  height: 48px;
  border: 4px solid var(--color-border);
  border-top-color: var(--color-primary);
  border-radius: 50%;
  animation: spin 1s linear infinite;
  margin-bottom: var(--spacing-sm);
}

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

#statusText {
  color: var(--color-text-secondary);
  font-size: 0.875rem;
}

/* ==================== 进度条 ==================== */
.progress-bar-container {
  margin-bottom: var(--spacing-lg);
}

.progress-bar {
  width: 100%;
  height: 8px;
  background: var(--color-surface);
  border-radius: 100px;
  overflow: hidden;
  margin-bottom: var(--spacing-sm);
  box-shadow: inset 0 2px 4px rgba(0, 0, 0, 0.2);
}

.progress-fill {
  height: 100%;
  background: var(--success-gradient);
  border-radius: 100px;
  transition: width var(--transition-slow);
  width: 0%;
  position: relative;
  overflow: hidden;
}

.progress-fill::after {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background: linear-gradient(90deg, transparent, rgba(255,255,255,0.3), transparent);
  animation: shimmer 2s infinite;
}

@keyframes shimmer {
  0% { transform: translateX(-100%); }
  100% { transform: translateX(100%); }
}

.progress-text {
  text-align: center;
  color: var(--color-text-secondary);
  font-size: 0.875rem;
}

/* ==================== 操作按钮 ==================== */
.action-buttons {
  display: flex;
  justify-content: center;
  gap: var(--spacing-md);
  flex-wrap: wrap;
}

/* ==================== Toast 提示 ==================== */
.toast {
  position: fixed;
  bottom: var(--spacing-lg);
  left: 50%;
  transform: translateX(-50%) translateY(100px);
  background: var(--color-surface);
  color: var(--color-text-primary);
  padding: var(--spacing-md) var(--spacing-lg);
  border-radius: var(--radius-md);
  box-shadow: var(--shadow-lg);
  border: 1px solid var(--color-border);
  z-index: 1000;
  transition: transform var(--transition-base);
  max-width: 400px;
  backdrop-filter: blur(10px);
}

.toast.show {
  transform: translateX(-50%) translateY(0);
}

.toast.error {
  border-color: var(--color-error);
  background: rgba(245, 87, 108, 0.1);
}

.toast.success {
  border-color: var(--color-success);
  background: rgba(0, 242, 254, 0.1);
}

/* ==================== 工具类 ==================== */
.hidden {
  display: none !important;
}

/* ==================== 动画 ==================== */
@keyframes fadeIn {
  from {
    opacity: 0;
    transform: translateY(20px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

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

/* ==================== 响应式设计 ==================== */
@media (max-width: 768px) {
  .container {
    padding: var(--spacing-md);
  }
  
  .logo h1 {
    font-size: 2rem;
  }
  
  .image-container {
    grid-template-columns: 1fr;
    gap: var(--spacing-md);
  }
  
  .arrow {
    transform: rotate(90deg);
  }
  
  .image-wrapper img,
  .result-placeholder {
    max-height: 300px;
  }
  
  .action-buttons {
    flex-direction: column;
  }
  
  .btn {
    width: 100%;
    justify-content: center;
  }
}

@media (max-width: 480px) {
  .logo h1 {
    font-size: 1.5rem;
  }
  
  .subtitle {
    font-size: 1rem;
  }
  
  .upload-area {
    padding: var(--spacing-lg);
  }
}