fix: 品牌设置页重写，匹配原版设计

- 三个上传框横排（二维码/背景图/Logo），100x100虚线框
- 点击上传，有预览，有清除按钮
- 上传前自动压缩图片（QR/Logo≤500KB，背景≤1MB）
- 品牌名称+对齐方式（靠左/居中/靠右）
- 配方卡片迷你预览（280x180，展示QR/Logo/背景/品牌名效果）
- 加载时读取brand_align
- 上传失败显示具体错误
- 重置file input允许重复选择同一文件

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

frontend/src/views/MyDiary.vue

@@ -113,48 +113,76 @@
         <button class="btn-return" @click="goBackToRecipe">← 返回配方卡片</button>
       </div>
       <div class="section-card">
-        <h4>🏷️ 品牌设置</h4>
+        <p style="font-size:13px;color:var(--text-light);margin-bottom:16px">分享配方卡片时，二维码、背景图、Logo 会自动展示在卡片上</p>
 
-        <div class="form-group">
-          <label>品牌名称</label>
-          <input v-model="brandName" class="form-input" placeholder="您的品牌名称" @blur="saveBrandSettings" />
-        </div>
+        <!-- Three upload areas side by side -->
+        <div style="display:flex;gap:20px;flex-wrap:wrap;margin-bottom:16px">
+          <!-- QR Code -->
+          <div>
+            <label class="form-label">📱 二维码</label>
+            <p style="font-size:11px;color:var(--text-light);margin-bottom:6px">卡片右上角展示</p>
+            <div class="upload-box" @click="triggerUpload('qr')">
+              <img v-if="brandQrImage" :src="brandQrImage" class="upload-box-img" />
+              <span v-else class="upload-box-hint">点击上传</span>
+            </div>
+            <input ref="qrInput" type="file" accept="image/*" style="display:none" @change="handleUpload('qr', $event)" />
+            <button v-if="brandQrImage" class="btn-clear" @click="clearBrandImage('qr')">清除</button>
+          </div>
 
-        <div class="form-group">
-          <label>二维码链接</label>
-          <input v-model="brandQrUrl" class="form-input" placeholder="https://..." @blur="saveBrandSettings" />
-          <div v-if="brandQrUrl" class="qr-preview">
-            <img :src="'https://api.qrserver.com/v1/create-qr-code/?size=120x120&data=' + encodeURIComponent(brandQrUrl)" alt="QR" class="qr-img" />
+          <!-- Background -->
+          <div>
+            <label class="form-label">🖼 背景图</label>
+            <p style="font-size:11px;color:var(--text-light);margin-bottom:6px">铺满整张卡片，半透明</p>
+            <div class="upload-box" @click="triggerUpload('bg')">
+              <img v-if="brandBg" :src="brandBg" class="upload-box-img" />
+              <span v-else class="upload-box-hint">点击上传</span>
+            </div>
+            <input ref="bgInput" type="file" accept="image/*" style="display:none" @change="handleUpload('bg', $event)" />
+            <button v-if="brandBg" class="btn-clear" @click="clearBrandImage('bg')">清除</button>
+          </div>
+
+          <!-- Logo -->
+          <div>
+            <label class="form-label">🏷 Logo</label>
+            <p style="font-size:11px;color:var(--text-light);margin-bottom:6px">卡片底部居中水印</p>
+            <div class="upload-box" @click="triggerUpload('logo')">
+              <img v-if="brandLogo" :src="brandLogo" class="upload-box-img" />
+              <span v-else class="upload-box-hint">点击上传</span>
+            </div>
+            <input ref="logoInput" type="file" accept="image/*" style="display:none" @change="handleUpload('logo', $event)" />
+            <button v-if="brandLogo" class="btn-clear" @click="clearBrandImage('logo')">清除</button>
           </div>
         </div>
 
+        <!-- Brand name -->
         <div class="form-group">
-          <label>我的二维码图片</label>
-          <div class="upload-area" @click="triggerUpload('qr')">
-            <img v-if="brandQrImage" :src="brandQrImage" class="upload-preview qr-upload-preview" />
-            <span v-else class="upload-hint">📲 点击上传二维码图片</span>
+          <label class="form-label">品牌名称或标语（显示在二维码下方）</label>
+          <textarea v-model="brandName" class="form-control" rows="2" placeholder="扫码申请成为优惠顾客&#10;我的精油小屋" style="max-width:350px;font-size:13px" @blur="saveBrandSettings"></textarea>
+          <div style="display:flex;gap:6px;margin-top:6px">
+            <button class="btn-align" :class="{ active: brandAlign === 'left' }" @click="brandAlign='left'; saveBrandSettings()">靠左</button>
+            <button class="btn-align" :class="{ active: brandAlign === 'center' }" @click="brandAlign='center'; saveBrandSettings()">居中</button>
+            <button class="btn-align" :class="{ active: brandAlign === 'right' }" @click="brandAlign='right'; saveBrandSettings()">靠右</button>
           </div>
-          <input ref="qrInput" type="file" accept="image/*" style="display:none" @change="handleUpload('qr', $event)" />
-          <div class="field-hint">上传后将显示在配方卡片右下角</div>
         </div>
 
-        <div class="form-group">
-          <label>品牌Logo</label>
-          <div class="upload-area" @click="triggerUpload('logo')">
-            <img v-if="brandLogo" :src="brandLogo" class="upload-preview" />
-            <span v-else class="upload-hint">点击上传Logo</span>
+        <!-- Card Preview -->
+        <div style="margin-bottom:16px">
+          <label class="form-label">📋 配方卡片预览</label>
+          <div class="card-preview-mini">
+            <div v-if="brandBg" class="card-preview-bg" :style="{ backgroundImage: 'url(' + brandBg + ')' }"></div>
+            <div class="card-preview-content">
+              <div style="font-size:8px;letter-spacing:2px;color:var(--sage);margin-bottom:4px">doTERRA · RECIPE CARD</div>
+              <div style="font-size:14px;font-weight:700;color:var(--text-dark)">配方名称</div>
+              <div style="font-size:10px;color:var(--text-light);margin-top:2px">薰衣草 · 乳香 · 茶树</div>
+            </div>
+            <img v-if="brandQrImage" :src="brandQrImage" class="card-preview-qr" />
+            <img v-if="brandLogo" :src="brandLogo" class="card-preview-logo" />
+            <div class="card-preview-cost">💰 ¥12.50</div>
+            <div v-if="brandName" class="card-preview-brand" :style="{ textAlign: brandAlign }">{{ brandName }}</div>
           </div>
-          <input ref="logoInput" type="file" accept="image/*" style="display:none" @change="handleUpload('logo', $event)" />
         </div>
 
-        <div class="form-group">
-          <label>卡片背景</label>
-          <div class="upload-area" @click="triggerUpload('bg')">
-            <img v-if="brandBg" :src="brandBg" class="upload-preview wide" />
-            <span v-else class="upload-hint">点击上传背景图</span>
-          </div>
-          <input ref="bgInput" type="file" accept="image/*" style="display:none" @change="handleUpload('bg', $event)" />
-        </div>
+        <button class="btn btn-primary" @click="saveBrandSettings">💾 保存品牌设置</button>
       </div>
     </div>
 
@@ -241,6 +269,7 @@ const brandQrUrl = ref('')
 const brandQrImage = ref('')
 const brandLogo = ref('')
 const brandBg = ref('')
+const brandAlign = ref('center')
 const logoInput = ref(null)
 const bgInput = ref(null)
 const qrInput = ref(null)
@@ -362,6 +391,7 @@ async function loadBrandSettings() {
       brandQrImage.value = data.qr_code || ''
       brandLogo.value = data.brand_logo || ''
       brandBg.value = data.brand_bg || ''
+      brandAlign.value = data.brand_align || 'center'
     }
   } catch {
     // no brand settings yet
@@ -374,7 +404,7 @@ async function saveBrandSettings() {
       method: 'PUT',
       body: JSON.stringify({
         brand_name: brandName.value,
-        qr_url: brandQrUrl.value,
+        brand_align: brandAlign.value,
       }),
     })
   } catch {
@@ -397,11 +427,43 @@ function readFileAsBase64(file) {
   })
 }
 
+// Compress image if too large
+function compressImage(base64, maxSize = 500000) {
+  return new Promise((resolve) => {
+    if (base64.length <= maxSize) { resolve(base64); return }
+    const img = new Image()
+    img.onload = () => {
+      const canvas = document.createElement('canvas')
+      let w = img.width, h = img.height
+      // Scale down if very large
+      const maxDim = 800
+      if (w > maxDim || h > maxDim) {
+        const ratio = Math.min(maxDim / w, maxDim / h)
+        w = Math.round(w * ratio)
+        h = Math.round(h * ratio)
+      }
+      canvas.width = w
+      canvas.height = h
+      canvas.getContext('2d').drawImage(img, 0, 0, w, h)
+      let quality = 0.8
+      let result = canvas.toDataURL('image/jpeg', quality)
+      while (result.length > maxSize && quality > 0.2) {
+        quality -= 0.1
+        result = canvas.toDataURL('image/jpeg', quality)
+      }
+      resolve(result)
+    }
+    img.src = base64
+  })
+}
+
 async function handleUpload(type, event) {
   const file = event.target.files[0]
   if (!file) return
   try {
-    const base64 = await readFileAsBase64(file)
+    let base64 = await readFileAsBase64(file)
+    const maxSize = type === 'bg' ? 1000000 : 500000
+    base64 = await compressImage(base64, maxSize)
     const fieldMap = { logo: 'brand_logo', bg: 'brand_bg', qr: 'qr_code' }
     const field = fieldMap[type]
     if (!field) return
@@ -414,9 +476,31 @@ async function handleUpload(type, event) {
       else if (type === 'bg') brandBg.value = base64
       else if (type === 'qr') brandQrImage.value = base64
       ui.showToast('上传成功')
+    } else {
+      const err = await res.json().catch(() => ({}))
+      ui.showToast(err.detail || '上传失败')
     }
+  } catch (e) {
+    ui.showToast('上传失败: ' + (e.message || ''))
+  }
+  // Reset input so same file can be re-selected
+  event.target.value = ''
+}
+
+async function clearBrandImage(type) {
+  const fieldMap = { logo: 'brand_logo', bg: 'brand_bg', qr: 'qr_code' }
+  const field = fieldMap[type]
+  try {
+    await api('/api/brand', {
+      method: 'PUT',
+      body: JSON.stringify({ [field]: null }),
+    })
+    if (type === 'logo') brandLogo.value = ''
+    else if (type === 'bg') brandBg.value = ''
+    else if (type === 'qr') brandQrImage.value = ''
+    ui.showToast('已清除')
   } catch {
-    ui.showToast('上传失败')
+    ui.showToast('清除失败')
   }
 }
 
@@ -853,6 +937,115 @@ async function applyBusiness() {
   color: #b0aab5;
 }
 
+/* Upload box (matching initial commit style) */
+.upload-box {
+  width: 100px;
+  height: 100px;
+  border: 2px dashed var(--border, #e0d4c0);
+  border-radius: 12px;
+  display: flex;
+  align-items: center;
+  justify-content: center;
+  cursor: pointer;
+  overflow: hidden;
+  background: white;
+  transition: border-color 0.15s;
+}
+.upload-box:hover { border-color: var(--sage, #7a9e7e); }
+.upload-box-img { width: 100%; height: 100%; object-fit: cover; }
+.upload-box-hint { font-size: 12px; color: var(--text-light, #9a8570); }
+.btn-clear {
+  margin-top: 6px;
+  font-size: 11px;
+  background: none;
+  border: 1px solid var(--border);
+  border-radius: 6px;
+  padding: 2px 8px;
+  cursor: pointer;
+  color: var(--text-light);
+}
+.btn-clear:hover { border-color: #c0392b; color: #c0392b; }
+.btn-align {
+  font-size: 11px;
+  padding: 3px 10px;
+  border: 1.5px solid var(--border);
+  border-radius: 6px;
+  background: white;
+  cursor: pointer;
+  color: var(--text-mid);
+}
+.btn-align.active {
+  background: var(--sage-mist);
+  border-color: var(--sage);
+  color: var(--sage-dark);
+}
+
+/* Card preview mini */
+.card-preview-mini {
+  position: relative;
+  width: 280px;
+  height: 180px;
+  background: linear-gradient(145deg, #faf7f0, #f5ede0);
+  border-radius: 14px;
+  border: 1px solid #e0ccaa;
+  overflow: hidden;
+  font-family: 'Noto Serif SC', serif;
+  padding: 16px;
+}
+.card-preview-bg {
+  position: absolute;
+  inset: 0;
+  background-size: cover;
+  background-position: center;
+  opacity: 0.15;
+}
+.card-preview-content { position: relative; z-index: 1; }
+.card-preview-qr {
+  position: absolute;
+  top: 10px;
+  right: 10px;
+  width: 40px;
+  height: 40px;
+  object-fit: cover;
+  border-radius: 4px;
+  z-index: 1;
+}
+.card-preview-logo {
+  position: absolute;
+  bottom: 40px;
+  left: 50%;
+  transform: translateX(-50%);
+  height: 20px;
+  width: auto;
+  object-fit: contain;
+  z-index: 1;
+}
+.card-preview-cost {
+  position: absolute;
+  bottom: 12px;
+  left: 16px;
+  right: 16px;
+  height: 24px;
+  background: linear-gradient(135deg, var(--sage), #5a7d5e);
+  border-radius: 6px;
+  display: flex;
+  align-items: center;
+  justify-content: center;
+  color: white;
+  font-size: 10px;
+  z-index: 1;
+}
+.card-preview-brand {
+  position: absolute;
+  bottom: 40px;
+  left: 16px;
+  right: 16px;
+  font-size: 9px;
+  color: var(--text-light);
+  z-index: 1;
+  white-space: pre-line;
+}
+
 .hint-text {
   font-size: 13px;
   color: #6b6375;