:root {
  --bg: #f7f8fc;
  --card: #ffffff;
  --text: #1f2937;
  --text-muted: #6b7280;
  --border: #e5e7eb;
  --primary: #4f46e5;
  --primary-hover: #4338ca;
  --accent: #0ea5e9;
  --shadow: 0 4px 20px rgba(31, 41, 55, 0.08);
  --radius: 16px;
}

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

[hidden] {
  display: none !important;
}

body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC",
    "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
  background: var(--bg);
  color: var(--text);
  line-height: 1.6;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

.app-header {
  text-align: center;
  padding: 48px 24px 24px;
}

.app-header h1 {
  font-size: 2rem;
  font-weight: 700;
  background: linear-gradient(135deg, var(--primary), var(--accent));
  -webkit-background-clip: text;
  background-clip: text;
  -webkit-text-fill-color: transparent;
  margin-bottom: 8px;
}

.subtitle {
  color: var(--text-muted);
  font-size: 1rem;
}

.container {
  flex: 1;
  max-width: 1100px;
  width: 100%;
  margin: 0 auto;
  padding: 0 24px 48px;
}

.upload-section {
  margin-bottom: 32px;
}

.upload-box {
  border: 2px dashed var(--border);
  border-radius: var(--radius);
  padding: 64px 32px;
  text-align: center;
  background: var(--card);
  cursor: pointer;
  transition: all 0.25s ease;
  box-shadow: var(--shadow);
}

.upload-box:hover,
.upload-box.dragover {
  border-color: var(--primary);
  background: #f5f3ff;
  transform: translateY(-2px);
}

.upload-icon {
  width: 56px;
  height: 56px;
  color: var(--primary);
  margin: 0 auto 16px;
}

.upload-text {
  font-size: 1.1rem;
  font-weight: 600;
  margin-bottom: 4px;
}

.upload-hint {
  font-size: 0.875rem;
  color: var(--text-muted);
}

.control-bar {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 20px;
  background: var(--card);
  border-radius: var(--radius);
  padding: 16px 24px;
  margin-bottom: 24px;
  box-shadow: var(--shadow);
}

.control-group {
  display: flex;
  align-items: center;
  gap: 8px;
  flex-wrap: wrap;
}

.control-group label {
  font-size: 0.9rem;
  font-weight: 500;
  color: var(--text);
}

select {
  padding: 6px 12px;
  border: 1px solid var(--border);
  border-radius: 8px;
  background: #fff;
  font-size: 0.9rem;
  cursor: pointer;
  outline: none;
}

select:focus {
  border-color: var(--primary);
}

.switch-label {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  cursor: pointer;
  user-select: none;
}

.switch-label input[type="checkbox"] {
  width: 16px;
  height: 16px;
  accent-color: var(--primary);
  cursor: pointer;
}

.btn-secondary {
  margin-left: auto;
  padding: 8px 20px;
  background: #fff;
  color: var(--primary);
  border: 1px solid var(--primary);
  border-radius: 8px;
  font-size: 0.9rem;
  font-weight: 600;
  cursor: pointer;
  transition: all 0.2s ease;
}

.btn-secondary:hover {
  background: var(--primary);
  color: #fff;
}

.btn-primary {
  padding: 8px 16px;
  background: var(--primary);
  color: #fff;
  border: 1px solid var(--primary);
  border-radius: 8px;
  font-size: 0.875rem;
  font-weight: 600;
  cursor: pointer;
  transition: all 0.2s ease;
  white-space: nowrap;
}

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

.btn-primary:disabled {
  opacity: 0.45;
  cursor: not-allowed;
}

.result-section {
  display: flex;
  flex-direction: column;
  gap: 24px;
}

.preview-card,
.palette-card {
  background: var(--card);
  border-radius: var(--radius);
  padding: 24px;
  box-shadow: var(--shadow);
}

.preview-card h2,
.palette-card h2 {
  font-size: 1.1rem;
  color: var(--text);
}

.palette-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  margin-bottom: 16px;
}

.preview-card h2 {
  margin-bottom: 16px;
}

.image-wrapper {
  border-radius: 12px;
  overflow: hidden;
  background: #f3f4f6;
  min-height: 220px;
  max-height: 520px;
  display: flex;
  align-items: center;
  justify-content: center;
}

.image-wrapper img {
  max-width: 100%;
  max-height: 520px;
  object-fit: contain;
  display: block;
}

.palette-list {
  display: flex;
  flex-direction: row;
  flex-wrap: wrap;
  gap: 12px;
}

.color-item {
  display: flex;
  flex-direction: column;
  align-items: stretch;
  gap: 10px;
  padding: 12px;
  border-radius: 12px;
  background: #f9fafb;
  border: 1px solid var(--border);
  transition: transform 0.15s ease;
  flex: 1 1 140px;
  min-width: 132px;
  max-width: 180px;
}

.color-item:hover {
  transform: translateY(-3px);
}

.color-swatch {
  width: 100%;
  height: 72px;
  border-radius: 10px;
  flex-shrink: 0;
  box-shadow: inset 0 0 0 1px rgba(0, 0, 0, 0.1);
  cursor: pointer;
}

.color-info {
  display: flex;
  flex-direction: column;
  gap: 6px;
}

.color-info .label {
  font-size: 0.75rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: var(--text-muted);
}

.color-info .value {
  font-family: "SFMono-Regular", Consolas, "Liberation Mono", Menlo, monospace;
  font-size: 0.9rem;
  font-weight: 500;
  color: var(--text);
  cursor: pointer;
  transition: color 0.15s ease;
}

.color-info .value:hover {
  color: var(--primary);
}

.app-footer {
  text-align: center;
  padding: 24px;
  color: var(--text-muted);
  font-size: 0.85rem;
}

.toast {
  position: fixed;
  bottom: 32px;
  left: 50%;
  transform: translateX(-50%) translateY(100px);
  background: #1f2937;
  color: #fff;
  padding: 12px 24px;
  border-radius: 8px;
  font-size: 0.9rem;
  opacity: 0;
  transition: all 0.3s ease;
  pointer-events: none;
  z-index: 1000;
}

.toast.show {
  transform: translateX(-50%) translateY(0);
  opacity: 1;
}