/* =====================================================================
   相册页样式
   依赖 _variables.css 中的 CSS 自定义属性
   瀑布流由 Masonry.js 控制，CSS 仅提供列宽和卡片样式
   ===================================================================== */

/* ---- 页面容器 ---- */
.albums {
    max-width: var(--container-width);
    margin: 0 auto;
    padding: var(--spacing-lg) var(--spacing-md);
}

/* =====================================================================
   页头
   ===================================================================== */
.albums__header {
    margin-bottom: var(--spacing-xl);
    padding-bottom: var(--spacing-md);
    border-bottom: 2px solid var(--color-border);
}

.albums__title {
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--color-text-main);
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    margin-bottom: var(--spacing-sm);
}

.albums__title i {
    color: var(--color-primary);
}

.albums__subtitle {
    color: var(--color-text-secondary);
    font-size: 0.95rem;
    margin-bottom: var(--spacing-sm);
}

.albums__stats {
    display: inline-flex;
    gap: var(--spacing-lg);
    font-size: 0.85rem;
    color: var(--color-text-muted);
}

/* =====================================================================
   瀑布流网格（Masonry.js 控制布局）
   - Masonry 使用 absolute 定位，容器需要 position: relative
   - 列宽通过 .albums__grid-sizer 控制
   ===================================================================== */
.albums__grid {
    position: relative;           /* Masonry 绝对定位的锚点 */
    opacity: 0;                   /* 初始隐藏，Masonry 排定位置后淡入，避免闪烁 */
    transition: opacity 0.3s ease;
}

/* Masonry 初始化完毕后加上此类，触发淡入 */
.albums__grid--ready {
    opacity: 1;
}

/* 列宽基准（不可见）及卡片列宽 */
/* 4 列：gutter=16px，3 个间隙共 48px，每列 = (100% - 48px) / 4 = 25% - 12px */
.albums__grid-sizer,
.albums__item {
    width: calc(25% - 12px);
    margin-bottom: 16px;
}

@media (max-width: 1200px) {
    /* 3 列：(100% - 32px) / 3  33.333% - 10.667px */
    .albums__grid-sizer,
    .albums__item {
        width: calc(33.333% - 11px);
    }
}

@media (max-width: 768px) {
    /* 2 列：(100% - 16px) / 2 = 50% - 8px */
    .albums__grid-sizer,
    .albums__item {
        width: calc(50% - 8px);
    }
}

@media (max-width: 480px) {
    /* 1 列 */
    .albums__grid-sizer,
    .albums__item {
        width: 100%;
    }
}

/* =====================================================================
   相册卡片
   ===================================================================== */
.albums__card {
    position: relative;
    border-radius: var(--radius-md);
    overflow: hidden;
    background: var(--color-bg-surface);
    border: 1px solid var(--color-border);
    box-shadow: 0 1px 4px var(--color-shadow);
    cursor: zoom-in;
    transition: transform 0.25s ease, box-shadow 0.25s ease, border-color 0.25s ease;
}

.albums__card:hover {
    transform: translateY(-4px);
    box-shadow: 0 10px 28px var(--color-shadow);
    border-color: transparent;
    z-index: 1;
}

/* 图片容器：宽高比由 img 的 width/height 属性自动推断，预留正确高度 */
.albums__image-wrapper {
    position: relative;
    width: 100%;
    overflow: hidden;
    background-color: var(--color-bg-surface-alt); /* 图片加载前的占位背景 */
}

/* 图片：宽度 100%，高度 auto，浏览器根据 width/height 属性自动计算宽高比 */
.albums__image {
    display: block;
    width: 100%;
    height: auto;
    transition: transform 0.35s ease, opacity 0.3s ease;
    opacity: 0;
}

/* 图片加载完成后淡入（由 JS 添加 is-loaded 类） */
.albums__image.is-loaded {
    opacity: 1;
}

/* hover 轻微缩放 */
.albums__card:hover .albums__image {
    transform: scale(1.04);
}

/* =====================================================================
   覆层（hover 时显示操作和图片信息）
   ===================================================================== */
.albums__overlay {
    position: absolute;
    inset: 0;
    background: linear-gradient(
        to bottom,
        rgba(0, 0, 0, 0.0) 0%,
        rgba(0, 0, 0, 0.0) 45%,
        rgba(0, 0, 0, 0.65) 100%
    );
    opacity: 0;
    transition: opacity 0.25s ease;
    display: flex;
    flex-direction: column;
    justify-content: space-between;
    padding: var(--spacing-sm) var(--spacing-sm) var(--spacing-md);
    pointer-events: none;
}

.albums__card:hover .albums__overlay {
    opacity: 1;
    pointer-events: auto;
}

/* 操作按钮区 */
.albums__actions {
    display: flex;
    gap: var(--spacing-sm);
    justify-content: flex-end;
}

.albums__action-btn {
    width: 34px;
    height: 34px;
    border-radius: 50%;
    background: rgba(255, 255, 255, 0.9);
    backdrop-filter: blur(4px);
    -webkit-backdrop-filter: blur(4px);
    border: none;
    color: #1a1a1a;
    display: flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    transition: transform 0.15s ease, background 0.15s ease;
    font-size: 0.85rem;
}

.albums__action-btn:hover {
    background: #ffffff;
    transform: scale(1.12);
}

/* 图片信息区 */
.albums__info {
    color: #ffffff;
    text-shadow: 0 1px 3px rgba(0, 0, 0, 0.6);
    transform: translateY(6px);
    transition: transform 0.25s ease;
}

.albums__card:hover .albums__info {
    transform: translateY(0);
}

.albums__desc {
    font-size: 0.875rem;
    font-weight: 500;
    margin-bottom: 4px;
    display: -webkit-box;
    -webkit-line-clamp: 2;
    -webkit-box-orient: vertical;
    overflow: hidden;
    line-height: 1.4;
}

.albums__meta {
    display: flex;
    flex-direction: column;
    gap: 2px;
    font-size: 0.75rem;
    opacity: 0.85;
}

.albums__meta-row {
    display: flex;
    justify-content: space-between;
    gap: var(--spacing-sm);
}

/* =====================================================================
   无限滚动：加载动画 & 无更多提示
   ===================================================================== */
.albums__loading {
    display: flex;
    justify-content: center;
    align-items: center;
    padding: var(--spacing-xl) 0;
    width: 100%;
}

.albums__spinner {
    width: 36px;
    height: 36px;
    border: 3px solid var(--color-bg-surface-alt);
    border-top-color: var(--color-primary);
    border-radius: 50%;
    animation: albums-spin 0.8s linear infinite;
}

@keyframes albums-spin {
    to { transform: rotate(360deg); }
}

.albums__no-more {
    text-align: center;
    padding: var(--spacing-xl) 0;
    color: var(--color-text-muted);
    font-size: 0.9rem;
}

/* =====================================================================
   移动端适配
   ===================================================================== */
@media (max-width: 480px) {
    .albums__header {
        margin-bottom: var(--spacing-lg);
    }

    .albums__title {
        font-size: 1.25rem;
    }

    .albums__stats {
        gap: var(--spacing-md);
    }
}