/* ========== 基础变量 ========== */
:root {
  --bg: #f8f6f3;
  --surface: #ffffff;
  --border: #e2ddd7;
  --text: #2c2c2c;
  --text-secondary: #777;
  --accent: #8b6f5c;
  --accent-hover: #725a49;
  --radius: 10px;
  --shadow: 0 2px 12px rgba(0,0,0,0.06);
  --font: 'Noto Sans SC', -apple-system, BlinkMacSystemFont, sans-serif;
}

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

body {
  font-family: var(--font);
  background: var(--bg);
  color: var(--text);
  min-height: 100vh;
}

/* ========== 头部 ========== */
.header {
  padding: 24px 32px 16px;
  border-bottom: 1px solid var(--border);
  background: var(--surface);
}
.logo {
  display: flex;
  align-items: center;
  gap: 12px;
  color: var(--accent);
}
.logo h1 {
  font-size: 22px;
  font-weight: 700;
  letter-spacing: 1px;
}
.subtitle {
  margin-top: 4px;
  font-size: 13px;
  color: var(--text-secondary);
  padding-left: 44px;
}

/* ========== 主布局 ========== */
.main-layout {
  display: flex;
  height: calc(100vh - 90px);
}

/* ========== 控制面板 ========== */
.control-panel {
  width: 320px;
  min-width: 320px;
  background: var(--surface);
  border-right: 1px solid var(--border);
  overflow-y: auto;
  padding: 20px;
}

.panel-section {
  margin-bottom: 24px;
}
.panel-section h3 {
  font-size: 13px;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 1.5px;
  color: var(--accent);
  margin-bottom: 14px;
  padding-bottom: 8px;
  border-bottom: 1px solid var(--border);
}

/* 上传区 */
.upload-zone {
  border: 2px dashed var(--border);
  border-radius: var(--radius);
  padding: 28px 16px;
  text-align: center;
  cursor: pointer;
  transition: all 0.25s;
  color: var(--text-secondary);
}
.upload-zone:hover,
.upload-zone.dragover {
  border-color: var(--accent);
  background: rgba(139,111,92,0.04);
  color: var(--accent);
}
.upload-zone svg { margin-bottom: 8px; opacity: 0.5; }
.upload-zone p { font-size: 13px; font-weight: 500; margin-bottom: 4px; }
.upload-zone span { font-size: 11px; opacity: 0.7; }

/* 示例图案 */
.sample-section {
  margin-top: 16px;
}
.sample-label {
  font-size: 12px;
  color: var(--text-secondary);
  margin-bottom: 10px;
}
.sample-grid {
  display: flex;
  gap: 8px;
  flex-wrap: wrap;
}
.sample-btn {
  width: 48px;
  height: 48px;
  border: 2px solid var(--border);
  border-radius: 10px;
  background: #fff;
  cursor: pointer;
  padding: 5px;
  transition: all 0.2s;
  display: flex;
  align-items: center;
  justify-content: center;
}
.sample-btn:hover {
  border-color: var(--accent);
  transform: scale(1.08);
  box-shadow: 0 2px 8px rgba(139,111,92,0.15);
}
.sample-btn svg {
  width: 100%;
  height: 100%;
}

/* 针法模式 */
.stitch-mode-grid {
  display: grid;
  grid-template-columns: 1fr 1fr 1fr;
  gap: 6px;
}
.stitch-mode-btn {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 5px;
  padding: 10px 6px;
  border: 2px solid var(--border);
  border-radius: 10px;
  background: var(--surface);
  cursor: pointer;
  transition: all 0.2s;
  color: var(--text-secondary);
}
.stitch-mode-btn svg {
  width: 28px;
  height: 28px;
}
.stitch-mode-btn span {
  font-size: 11px;
  font-weight: 500;
  font-family: var(--font);
}
.stitch-mode-btn:hover {
  border-color: var(--accent);
  color: var(--accent);
}
.stitch-mode-btn.active {
  background: var(--accent);
  border-color: var(--accent);
  color: #fff;
}

/* 控件组 */
.control-group {
  margin-bottom: 16px;
}
.control-group label {
  display: flex;
  align-items: center;
  gap: 6px;
  font-size: 13px;
  font-weight: 500;
  margin-bottom: 6px;
  color: var(--text);
}
.value-display {
  color: var(--accent);
  font-weight: 700;
  min-width: 28px;
  text-align: right;
}

/* 滑块 */
input[type="range"] {
  -webkit-appearance: none;
  width: 100%;
  height: 6px;
  border-radius: 3px;
  background: var(--border);
  outline: none;
}
input[type="range"]::-webkit-slider-thumb {
  -webkit-appearance: none;
  width: 18px;
  height: 18px;
  border-radius: 50%;
  background: var(--accent);
  cursor: pointer;
  box-shadow: 0 1px 4px rgba(0,0,0,0.2);
  transition: transform 0.15s;
}
input[type="range"]::-webkit-slider-thumb:hover {
  transform: scale(1.15);
}

/* 选择框 */
select {
  width: 100%;
  padding: 8px 12px;
  border: 1px solid var(--border);
  border-radius: 6px;
  font-family: var(--font);
  font-size: 13px;
  background: var(--surface);
  color: var(--text);
  cursor: pointer;
}

/* 颜色选择 */
.color-row {
  display: flex;
  align-items: center;
  gap: 10px;
}
input[type="color"] {
  -webkit-appearance: none;
  width: 36px;
  height: 36px;
  border: 2px solid var(--border);
  border-radius: 8px;
  cursor: pointer;
  padding: 2px;
}
input[type="color"]::-webkit-color-swatch-wrapper { padding: 0; }
input[type="color"]::-webkit-color-swatch { border: none; border-radius: 5px; }

.color-text {
  flex: 1;
  padding: 8px 10px;
  border: 1px solid var(--border);
  border-radius: 6px;
  font-family: monospace;
  font-size: 13px;
  color: var(--text);
}

/* 复选框 */
input[type="checkbox"] {
  accent-color: var(--accent);
  width: 16px;
  height: 16px;
}

/* 预设按钮 */
.preset-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 8px;
}
.preset-btn {
  padding: 10px;
  border: 1px solid var(--border);
  border-radius: 8px;
  background: var(--surface);
  font-family: var(--font);
  font-size: 13px;
  font-weight: 500;
  cursor: pointer;
  transition: all 0.2s;
  color: var(--text);
}
.preset-btn:hover {
  border-color: var(--accent);
  color: var(--accent);
}
.preset-btn.active {
  background: var(--accent);
  color: #fff;
  border-color: var(--accent);
}

/* 按钮 */
.export-buttons {
  display: flex;
  gap: 10px;
}
.btn {
  flex: 1;
  padding: 12px 16px;
  border: none;
  border-radius: 8px;
  font-family: var(--font);
  font-size: 13px;
  font-weight: 600;
  cursor: pointer;
  transition: all 0.2s;
}
.btn-primary {
  background: var(--accent);
  color: #fff;
}
.btn-primary:hover { background: var(--accent-hover); }
.btn-secondary {
  background: transparent;
  color: var(--accent);
  border: 1.5px solid var(--accent);
}
.btn-secondary:hover { background: rgba(139,111,92,0.08); }

/* ========== 画布区域 ========== */
.canvas-area {
  flex: 1;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  padding: 24px;
  overflow: auto;
  background:
    radial-gradient(circle at 20% 30%, rgba(139,111,92,0.03) 0%, transparent 60%),
    radial-gradient(circle at 80% 70%, rgba(139,111,92,0.03) 0%, transparent 60%);
}

.canvas-wrapper {
  position: relative;
  max-width: 100%;
  max-height: 100%;
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  overflow: hidden;
  background: #f5f0eb;
}

#previewCanvas {
  display: block;
  max-width: 100%;
  max-height: calc(100vh - 180px);
}

.empty-state {
  position: absolute;
  inset: 0;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 12px;
  color: var(--text-secondary);
  pointer-events: none;
}
.empty-state p { font-size: 15px; font-weight: 500; }
.empty-state span { font-size: 12px; opacity: 0.6; }

.canvas-info {
  margin-top: 12px;
  display: flex;
  gap: 24px;
  font-size: 12px;
  color: var(--text-secondary);
}

/* ========== 滚动条 ========== */
.control-panel::-webkit-scrollbar { width: 6px; }
.control-panel::-webkit-scrollbar-track { background: transparent; }
.control-panel::-webkit-scrollbar-thumb { background: var(--border); border-radius: 3px; }
.control-panel::-webkit-scrollbar-thumb:hover { background: #ccc; }

/* ========== 响应式 ========== */
@media (max-width: 860px) {
  .main-layout { flex-direction: column; height: auto; }
  .control-panel {
    width: 100%;
    min-width: auto;
    max-height: 400px;
    border-right: none;
    border-bottom: 1px solid var(--border);
  }
  .canvas-area { min-height: 50vh; }
}