/* 3D 背景选择面板（assets/features/space-backdrop/picker.js）：深色玻璃浮层，贴在 3D 空间左上工具条下；手机是底部抽屉。 */
.space-backdrop-btn { min-height: 44px; padding: 0 12px; border: 1px solid #71808d; border-radius: 8px; background: #27333c; color: #f3f4f6; cursor: pointer; }
.space-backdrop-btn[aria-expanded="true"] { border-color: #cbd5e1; }
.sbd-panel { position: absolute; top: 64px; left: 12px; z-index: var(--layer-stack-37, 37); width: min(420px, calc(100% - 24px)); max-height: min(70vh, calc(100% - 80px));
  display: flex; flex-direction: column; gap: 10px; padding: 12px; border-radius: 14px; background: rgba(20, 27, 34, .92); color: #e5e7eb;
  border: 1px solid rgba(148, 163, 184, .28); box-shadow: 0 18px 40px rgba(0, 0, 0, .35); backdrop-filter: blur(14px); -webkit-backdrop-filter: blur(14px); }
.sbd-panel.sbd-sheet { position: fixed; top: auto; left: 0; right: 0; bottom: 0; width: auto; max-height: 72vh; border-radius: 16px 16px 0 0; z-index: var(--layer-stack-10000, 10000); padding-bottom: max(12px, env(safe-area-inset-bottom)); }
.sbd-head { display: flex; align-items: center; justify-content: space-between; }
.sbd-head h2 { margin: 0; font-size: 15px; font-weight: 600; }
.sbd-close { width: 36px; height: 36px; border: 0; border-radius: 8px; background: transparent; color: #cbd5e1; cursor: pointer; }
.sbd-tabs { align-self: flex-start; background: rgba(255, 255, 255, .06); border-color: rgba(148, 163, 184, .25); }
.sbd-tabs button { min-height: 32px; padding: 0 12px; border: 0; border-radius: 6px; background: transparent; color: #cbd5e1; cursor: pointer; }
.sbd-tabs button[aria-selected="true"] { background: rgba(255, 255, 255, .14); color: #fff; }
.sbd-body { display: grid; grid-template-columns: repeat(3, minmax(0, 1fr)); gap: 8px; overflow-y: auto; overscroll-behavior: contain; padding: 2px; }
.sbd-body > :is(.sbd-chips, .sbd-note, .sbd-upload, .sbd-prompt, .sbd-ai-row, .ui-segmented, .moderation-notice) { grid-column: 1 / -1; }
.sbd-tile { position: relative; display: flex; flex-direction: column; gap: 4px; padding: 0; border: 2px solid transparent; border-radius: 10px; background: none; color: inherit; cursor: pointer; text-align: left; }
.sbd-tile[aria-checked="true"] { border-color: #e5e7eb; }
.sbd-art { display: block; aspect-ratio: 2 / 1; overflow: hidden; border-radius: 8px; background: #111827; }
.sbd-art img { display: block; width: 100%; height: auto; } /* Poly Haven 预览图上 2/3 是全景，宽 100% 时正好露出这一截 */
.sbd-swatch { display: block; width: 100%; height: 100%; }
.sbd-name { padding: 0 4px 4px; font-size: 12px; line-height: 1.3; white-space: nowrap; overflow: hidden; text-overflow: ellipsis; }
.sbd-badge { position: absolute; top: 4px; left: 4px; padding: 1px 6px; border-radius: 6px; background: rgba(0, 0, 0, .55); font-size: 11px; }
.sbd-cloud { margin: 0 4px 4px; padding: 3px 6px; border-radius: 6px; background: rgba(255, 255, 255, .1); font-size: 11px; text-align: center; }
.sbd-chips { display: flex; flex-wrap: wrap; gap: 6px; }
.sbd-chips .ui-chip[aria-pressed="true"] { background: rgba(255, 255, 255, .16); color: #fff; }
.sbd-note { margin: 2px 0 0; font-size: 12px; color: #94a3b8; line-height: 1.5; }
.sbd-status { margin: 0; min-height: 1em; font-size: 12px; color: #cbd5e1; }
.sbd-status:empty { display: none; }
.sbd-upload { justify-content: center; }
.sbd-prompt { width: 100%; box-sizing: border-box; resize: vertical; padding: 8px 10px; border-radius: 8px; border: 1px solid rgba(148, 163, 184, .35); background: rgba(0, 0, 0, .25); color: #f1f5f9; font: inherit; font-size: 14px; }
.sbd-ai-row { display: flex; align-items: center; justify-content: space-between; gap: 8px; }
.sbd-price { font-size: 12px; color: #cbd5e1; }
@media (max-width: 520px) { .sbd-body { grid-template-columns: repeat(2, minmax(0, 1fr)); } }
@media (prefers-reduced-motion: no-preference) { .sbd-panel:not(.sbd-sheet) { animation: sbd-in .18s ease-out; } @keyframes sbd-in { from { opacity: 0; transform: translateY(-4px); } } }