/* ==========================================
   mobile.css —— 手机端专用样式（屏幕宽度 ≤ 640px）
   ========================================== */

@media screen and (max-width: 640px) {
    html {
        font-size: 14px;
    }

    /* 顶部 Banner */
    #gameBanner {
        padding: calc(8px + env(safe-area-inset-top)) 12px 8px;
        gap: 8px;
    }
    .banner-title {
        font-size: 1.3rem;
        letter-spacing: 2px;
        flex: 1;
        white-space: nowrap;
        overflow: hidden;
        text-overflow: ellipsis;
    }
    .banner-actions { gap: 8px; }
    .banner-actions button {
        width: 44px;
        height: 44px;
        font-size: 1.2rem;
    }

    /* 主布局：纵向排列 */
    #mainContainer {
        flex-direction: column;
        overflow: visible;
    }

    /* ==========================================
       左侧资源面板
       ========================================== */
    #resourcePanel {
        width: 100%;
        max-height: none;
        overflow-y: visible;
        overflow-x: hidden;
        -webkit-overflow-scrolling: touch;
        padding: 10px;
        border-right: none;
        border-bottom: 2px solid var(--border-panel);
        display: block;
    }

    .panel-category {
        margin-top: 6px;
        display: block;
    }

    .category-header {
        width: 100%;
        min-height: auto;
        padding: 8px 12px;
        margin: 0 0 4px 0;
        background: var(--bg-resource-item);
        border: 2px solid transparent;
        border-radius: var(--radius-md);
        font-size: 0.85rem;
        font-weight: 700;
        display: flex;
        align-items: center;
        gap: 6px;
        color: var(--text-primary);
        cursor: pointer;
    }
    .category-header.active-category {
        border-color: var(--border-active);
        background: var(--bg-resource-active);
    }
    .category-header .cat-icon {
        width: 1em;
        height: 1em;
        flex-shrink: 0;
    }

    .category-items {
        display: none;
        margin-top: 2px;
        padding-left: 0;
    }
    .category-items.active {
        display: block;
    }

    .resource-item {
        min-height: 40px;
        padding: 6px 10px;
        margin-bottom: 4px;
        font-size: 0.82rem;
        overflow: visible;
    }
    .resource-item.no-production {
        min-height: 36px;
    }
    .resource-item .res-name {
        gap: 5px;
        font-size: 0.85rem;
        flex-shrink: 0;
    }
    .resource-item .res-stats {
        gap: 8px;
        font-size: 0.75rem;
        margin-top: 0 !important;
        justify-content: flex-end;
        flex-shrink: 0;
    }
    .resource-item.sub-item {
        font-size: 0.8rem;
    }

    #dmShopSideBtn {
        display: flex;
        flex-direction: row !important;
        justify-content: space-between;
        align-items: center;
        min-height: 40px;
        padding: 6px 10px;
        margin: 4px 0;
        border: 1px solid var(--border-card);
        border-radius: var(--radius-md);
        background: var(--bg-resource-item);
        overflow: visible;
    }
    #dmShopSideBtn .res-stats {
        margin-top: 0;
        width: auto;
        flex-shrink: 0;
    }

    /* 内容区 */
    #contentArea {
        padding: 12px 12px calc(20px + env(safe-area-inset-bottom));
        overflow: visible;
    }
    #clickBtn {
        width: 220px;
        min-height: 80px;
        padding: 18px 30px;
        font-size: 1.5rem;
    }
    #buildingsContainer { max-width: 100%; }
    #selectedResourceName {
        font-size: 1.15rem;
        margin-bottom: 12px;
    }
    .btn {
        min-height: 44px;
        padding: 10px 18px;
        font-size: 0.95rem;
    }

    /* 建筑卡片内部间距缩小 */
    .building-card {
        padding: 8px 10px;
        margin-bottom: 6px;
    }
    .building-header {
        margin-bottom: 3px;
    }
    .building-body {
        gap: 2px;
        margin-bottom: 4px;
    }
    .cost-line + .cost-line {
        margin-top: 2px;
    }

    /* 移动端字体缩小 */
    .building-desc {
        font-size: calc(0.8rem - 2px);
    }
    .cost-line {
        font-size: calc(0.85rem - 2px);
    }
    .cost-label {
        font-size: calc(0.85rem - 2px);
    }

    /* ==========================================
       移动端“列表-详情”切换 —— 固定返回按钮
       ========================================== */

    #backToResourcesBtn {
        display: none;
        width: 100%;
        padding: 10px 12px;
        margin-bottom: 10px;
        background: var(--bg-resource-item);
        border: 1px solid var(--border-card);
        border-radius: var(--radius-md);
        font-size: 0.95rem;
        color: var(--text-primary);
        text-align: left;
        cursor: pointer;
        transition: background 0.2s;
    }
    #backToResourcesBtn:active {
        background: var(--bg-resource-active);
    }

    body:not(.show-detail) #resourcePanel {
        display: block;
    }
    body:not(.show-detail) #contentArea {
        display: block;
    }

    body.show-detail #gameBanner {
        display: none !important;
    }
    body.show-detail #resourcePanel {
        display: none !important;
    }
    body.show-detail #backToResourcesBtn {
        display: block !important;
        position: fixed;
        top: 0;
        left: 0;
        z-index: 100000;          /* ★ 提高到最顶层，远超任何内容区域 */
        margin-bottom: 0;
        width: 100%;
        border-radius: 0;
        border-left: none;
        border-right: none;
        border-top: none;
    }

    /* 降低主容器和内容区的层叠优先级，避免意外覆盖按钮 */
    body.show-detail #mainContainer {
        overflow: visible;
        position: relative;
        z-index: 1;               /* 保持在底层 */
    }
    body.show-detail #contentArea {
        padding-top: 50px;
        padding-right: 12px;
        padding-bottom: calc(20px + env(safe-area-inset-bottom));
        padding-left: 12px;
        position: relative;
        z-index: 0;               /* 内容区在按钮之下 */
    }
}