/* ============ App Shell：底部导航 + Tab 视图 + 上传面板 + 拖拽遮罩 ============ */

/* Tab 视图容器：同一时间只显示一个 */
.tab-view { display: none; }
.tab-view.active { display: block; }

/* --- 底部导航 --- */
.bottom-nav {
    position: fixed;
    bottom: 0;
    left: 0;
    right: 0;
    background: var(--bg-card);
    border-top: 1px solid var(--border);
    z-index: 100;
    padding: 6px 0 calc(6px + env(safe-area-inset-bottom));
    box-shadow: 0 -4px 20px rgba(0, 0, 0, 0.3);
}

.bottom-nav-inner {
    max-width: 600px;
    margin: 0 auto;
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 0 16px;
}

.nav-item {
    flex: 1;
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 2px;
    background: none;
    border: none;
    color: var(--text-muted);
    font-family: var(--font-body);
    font-size: 11px;
    cursor: pointer;
    padding: 4px 0;
    transition: color 0.15s var(--ease);
    text-decoration: none;
}
.nav-item .nav-icon { font-size: 18px; line-height: 1; }
.nav-item:hover { color: var(--text); }
.nav-item.active { color: var(--accent); }

/* 中央凸起 "+" 上传按钮 */
.upload-fab {
    width: 52px;
    height: 52px;
    border-radius: 50%;
    background: var(--primary);
    color: white;
    border: 3px solid var(--bg-card);
    font-size: 26px;
    line-height: 1;
    display: flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    margin-top: -26px;
    flex-shrink: 0;
    box-shadow: 0 6px 20px var(--primary-glow);
    transition: transform 0.15s var(--ease), box-shadow 0.15s var(--ease);
}
.upload-fab:hover { transform: translateY(-2px) scale(1.05); box-shadow: 0 8px 26px var(--primary-glow); }
.upload-fab:active { transform: scale(0.95); }

/* --- 上传面板（FAB 弹出） --- */
.upload-sheet {
    position: fixed;
    bottom: 0;
    left: 0;
    right: 0;
    background: var(--bg-card);
    border-top: 1px solid var(--border);
    border-radius: 16px 16px 0 0;
    padding: 20px 24px calc(84px + env(safe-area-inset-bottom));
    z-index: 110;
    box-shadow: 0 -10px 40px rgba(0, 0, 0, 0.5);
    animation: sheetUp 0.25s var(--ease);
}
@keyframes sheetUp {
    from { transform: translateY(100%); opacity: 0; }
    to   { transform: translateY(0); opacity: 1; }
}
.upload-sheet[hidden] { display: none; }

.upload-sheet-title {
    font-family: var(--font-display);
    font-size: 16px;
    font-weight: 600;
    color: var(--text);
    margin-bottom: 4px;
}
.upload-sheet-sub {
    color: var(--text-muted);
    font-size: 13px;
    margin-bottom: 16px;
}
.upload-sheet-actions { display: flex; gap: 10px; flex-wrap: wrap; }

/* --- 全局拖拽遮罩 --- */
.drag-overlay {
    position: fixed;
    inset: 0;
    background: rgba(15, 23, 42, 0.85);
    border: 3px dashed var(--accent);
    z-index: 200;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    gap: 12px;
    color: var(--accent);
    animation: pulse 1.2s var(--ease) infinite;
    pointer-events: none;
}
.drag-overlay[hidden] { display: none; }
.drag-overlay .drag-overlay-icon { font-size: 56px; }
.drag-overlay .drag-overlay-text { font-size: 18px; font-weight: 500; font-family: var(--font-display); }

/* 内容区底部留白，避免被底部导航遮挡 */
.app-container { padding-bottom: 96px; }

/* 容器加宽（桌面端） */
@media (min-width: 1024px) {
    .container.app-container { max-width: 1400px; }
}

/* 面包屑导航 */
.breadcrumb-bar {
    display: flex;
    align-items: center;
    gap: 4px;
    padding: 8px 0;
    font-size: 13px;
    color: var(--text-muted);
    flex-wrap: wrap;
}
.breadcrumb-item {
    color: var(--primary);
    text-decoration: none;
    cursor: pointer;
    padding: 2px 6px;
    border-radius: var(--radius);
    transition: background 0.15s;
}
.breadcrumb-item:hover {
    background: var(--bg-elevated);
}
.breadcrumb-item.active {
    color: var(--text);
    font-weight: 600;
    cursor: default;
}
.breadcrumb-item.active:hover {
    background: transparent;
}
.breadcrumb-sep {
    color: var(--text-subtle);
    user-select: none;
}