/* 图片背景移除工具 */
.rbg-grid { display: grid; grid-template-columns: 320px minmax(0, 1fr); gap: 20px; align-items: start; }
.rbg-panel { background: var(--bg); border: 1px solid var(--rule); border-radius: var(--radius-md); padding: 20px; }
.rbg-sidebar { display: flex; flex-direction: column; gap: 16px; }
.rbg-main { display: flex; flex-direction: column; gap: 18px; }

.rbg-section { margin-bottom: 18px; }
.rbg-section:last-child { margin-bottom: 0; }
.rbg-section h3 { display: flex; align-items: center; gap: 6px; font-size: .95rem; margin: 0 0 12px; }
.rbg-section h3 i { color: var(--accent); }

.rbg-upload {
  border: 2px dashed var(--rule);
  border-radius: var(--radius-sm);
  padding: 22px 12px;
  text-align: center;
  cursor: pointer;
  transition: all .25s;
  background: var(--bg2);
}
.rbg-upload:hover, .rbg-upload.dragover { border-color: var(--accent); background: var(--accent-soft); }
.rbg-upload i { font-size: 1.8rem; color: var(--accent); margin-bottom: 8px; display: block; }
.rbg-upload p { color: var(--ink); font-size: .85rem; margin: 0 0 4px; }
.rbg-hint { color: var(--muted); font-size: .75rem; }

.rbg-mode-tabs { display: flex; gap: 4px; background: var(--bg2); border-radius: var(--radius-sm); padding: 3px; }
.rbg-mode-tab {
  flex: 1; padding: 7px 3px; border: none; border-radius: var(--radius-sm);
  background: transparent; font-size: .78rem; font-weight: 600; color: var(--muted);
  cursor: pointer; transition: all .2s; font-family: var(--font);
}
.rbg-mode-tab:hover { color: var(--ink); }
.rbg-mode-tab.active { background: var(--bg); color: var(--accent); box-shadow: 0 1px 3px rgba(0,0,0,.1); }

.rbg-mode-panel { display: none; margin-top: 10px; }
.rbg-mode-panel.active { display: block; }

.rbg-form-row { margin-bottom: 12px; }
.rbg-form-row label { display: block; font-size: .82rem; color: var(--muted); margin-bottom: 5px; font-weight: 500; }
.rbg-form-row input[type="range"] { width: 100%; accent-color: var(--accent); }
.rbg-form-row input[type="range"] output { color: var(--accent); font-weight: 600; }

.rbg-select {
  width: 100%; padding: 8px 10px; border: 1px solid var(--rule); border-radius: var(--radius-sm);
  font-size: .85rem; background: var(--bg); color: var(--ink); box-sizing: border-box; outline: none;
}
.rbg-select:focus { border-color: var(--accent); box-shadow: 0 0 0 3px var(--accent-soft); }

.rbg-color-preview {
  width: 100%; height: 36px; border-radius: var(--radius-sm);
  border: 1px solid var(--rule); background: var(--bg2);
  display: flex; align-items: center; justify-content: center;
  font-size: .8rem; color: var(--muted);
}
.rbg-color-preview.has-color { border: 2px solid var(--accent); }

.rbg-actions { display: flex; flex-wrap: wrap; gap: 8px; }
.rbg-actions .btn { flex: 1; min-width: 90px; }

.rbg-preview-area {
  background: var(--bg2); border: 1px solid var(--rule); border-radius: var(--radius-md);
  padding: 16px; min-height: 320px; display: flex; align-items: center; justify-content: center; overflow: hidden;
}
.rbg-placeholder { text-align: center; color: var(--muted); }
.rbg-placeholder i { font-size: 3rem; margin-bottom: 12px; color: var(--rule); display: block; }
.rbg-placeholder p { margin: 0; }

.rbg-compare { display: grid; grid-template-columns: 1fr 1fr; gap: 16px; width: 100%; }
.rbg-compare-item { display: flex; flex-direction: column; align-items: center; gap: 8px; }
.rbg-compare-item canvas { max-width: 100%; max-height: 400px; border-radius: var(--radius-sm); border: 1px solid var(--rule); }
.rbg-compare-label { font-size: .85rem; font-weight: 600; color: var(--muted); }

.rbg-tips { border-top: 1px solid var(--rule); padding-top: 16px; }
.rbg-tips h4 { display: flex; align-items: center; gap: 6px; font-size: .9rem; margin: 0 0 12px; }
.rbg-tips h4 i { color: var(--accent); }
.rbg-tip-grid { display: grid; grid-template-columns: repeat(2, 1fr); gap: 10px; }
.rbg-tip-item { background: var(--bg2); border-radius: var(--radius-sm); padding: 10px 12px; border-left: 3px solid var(--accent); }
.rbg-tip-item strong { display: flex; align-items: center; gap: 6px; font-size: .82rem; color: var(--ink); margin-bottom: 3px; }
.rbg-tip-item strong i { color: var(--accent); }
.rbg-tip-item p { font-size: .75rem; color: var(--muted); margin: 0; line-height: 1.5; }

@media (max-width: 900px) {
  .rbg-grid { grid-template-columns: 1fr; }
  .rbg-tip-grid { grid-template-columns: 1fr; }
  .rbg-compare { grid-template-columns: 1fr; }
}