* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'PingFang SC', 'Hiragino Sans GB', 'Microsoft YaHei', sans-serif;
    background-color: #ffffff;
    color: #333;
    line-height: 1.6;
}

header {
    text-align: center;
    padding: 40px 20px;
    border-bottom: 1px solid #e5e5e5;
}

header h1 {
    font-size: 2.5rem;
    font-weight: 300;
    letter-spacing: 2px;
    color: #2c2c2c;
}

main {
    max-width: 1400px;
    margin: 0 auto;
    padding: 40px 20px;
}

.filter-buttons {
    display: flex;
    justify-content: center;
    gap: 15px;
    margin-bottom: 40px;
    flex-wrap: wrap;
}

.filter-btn {
    padding: 10px 24px;
    font-size: 1rem;
    font-family: inherit;
    background-color: transparent;
    border: 1px solid #ddd;
    border-radius: 25px;
    color: #666;
    cursor: pointer;
    transition: all 0.3s ease;
    outline: none;
}

.filter-btn:hover {
    border-color: #999;
    color: #333;
    background-color: #f9f9f9;
}

.filter-btn.active {
    background-color: #2c2c2c;
    color: #fff;
    border-color: #2c2c2c;
}

.filter-btn.active:hover {
    background-color: #1a1a1a;
    border-color: #1a1a1a;
}

.gallery {
    position: relative;
    column-count: 3;
    column-gap: 20px;
    column-fill: balance;
}

.gallery-item {
    position: relative;
    display: inline-block;
    width: 100%;
    margin-bottom: 20px;
    overflow: hidden;
    border-radius: 4px;
    background-color: #f5f5f5;
    cursor: pointer;
    transition: transform 0.3s ease, box-shadow 0.3s ease;
    break-inside: avoid;
    page-break-inside: avoid;
    -webkit-column-break-inside: avoid;
    user-select: none;
    -webkit-user-drag: none;
    -webkit-touch-callout: none;
    -webkit-tap-highlight-color: transparent;
}

.gallery-item:hover {
    transform: translateY(-5px);
    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.1);
}

.gallery-item img {
    width: 100%;
    height: auto;
    display: block;
    user-select: none;
    -webkit-user-drag: none;
    -khtml-user-drag: none;
    -moz-user-drag: none;
    -o-user-drag: none;
    pointer-events: none;
    -webkit-touch-callout: none;
    -webkit-tap-highlight-color: transparent;
    image-rendering: auto;
    -webkit-backface-visibility: hidden;
    backface-visibility: hidden;
}

.gallery-item.loading img {
    opacity: 0;
    position: absolute;
    visibility: hidden;
}

.gallery-item.loaded img {
    opacity: 1;
    position: relative;
    visibility: visible;
    transition: none;
}

.gallery-item.loading {
    min-height: 200px;
    background: linear-gradient(90deg, #f0f0f0 25%, #e0e0e0 50%, #f0f0f0 75%);
    background-size: 200% 100%;
    animation: loading 1.5s ease-in-out infinite;
}

.gallery-item.loaded {
    background: transparent;
}

@keyframes loading {
    0% {
        background-position: 200% 0;
    }
    100% {
        background-position: -200% 0;
    }
}

/* 模态框样式 */
.modal {
    display: none;
    position: fixed;
    z-index: 1000;
    left: 0;
    top: 0;
    width: 100%;
    height: 100%;
    background-color: rgba(0, 0, 0, 0.9);
    overflow: auto;
    animation: fadeIn 0.3s ease;
}

.modal.show {
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
}

@keyframes fadeIn {
    from {
        opacity: 0;
    }
    to {
        opacity: 1;
    }
}

.modal-content {
    max-width: 90%;
    max-height: 90vh;
    margin: auto;
    display: block;
    object-fit: contain;
    animation: zoomIn 0.3s ease;
    transition: opacity 0.2s ease;
    user-select: none;
    -webkit-user-drag: none;
    -khtml-user-drag: none;
    -moz-user-drag: none;
    -o-user-drag: none;
    pointer-events: auto;
}

.modal-content.loading {
    opacity: 0.5;
}

@keyframes zoomIn {
    from {
        transform: scale(0.8);
        opacity: 0;
    }
    to {
        transform: scale(1);
        opacity: 1;
    }
}

.close {
    position: absolute;
    top: 30px;
    right: 40px;
    color: #fff;
    font-size: 40px;
    font-weight: bold;
    cursor: pointer;
    z-index: 1001;
    transition: opacity 0.3s ease;
    line-height: 1;
}

.close:hover {
    opacity: 0.7;
}

.nav-arrow {
    position: absolute;
    top: 50%;
    transform: translateY(-50%);
    background: none;
    border: none;
    width: 40px;
    height: 40px;
    cursor: pointer;
    z-index: 1001;
    padding: 0;
    user-select: none;
    opacity: 0.9;
    transition: all 0.3s ease;
}

.nav-arrow::before {
    content: '';
    position: absolute;
    top: 50%;
    left: 50%;
    width: 20px;
    height: 20px;
    border-top: 2px solid #fff;
    border-right: 2px solid #fff;
    transition: all 0.3s ease;
}

/* 左侧：上一张，尖头朝左 */
.nav-arrow-left::before {
    transform: translate(-50%, -50%) rotate(225deg);
}

/* 右侧：下一张，尖头朝右 */
.nav-arrow-right::before {
    transform: translate(-50%, -50%) rotate(45deg);
}

.nav-arrow:hover {
    opacity: 1;
}

.nav-arrow-left:hover::before {
    transform: translate(-50%, -50%) rotate(225deg) scale(1.2);
}

.nav-arrow-right:hover::before {
    transform: translate(-50%, -50%) rotate(45deg) scale(1.2);
}

.nav-arrow:active {
    opacity: 0.7;
}

.nav-arrow-left:active::before {
    transform: translate(-50%, -50%) rotate(225deg) scale(0.9);
}

.nav-arrow-right:active::before {
    transform: translate(-50%, -50%) rotate(45deg) scale(0.9);
}

.nav-arrow-left {
    left: 30px;
}

.nav-arrow-right {
    right: 30px;
}

.nav-arrow.hidden {
    display: none;
}

/* 响应式设计 - 移动端双列 */
@media (max-width: 768px) {
    header h1 {
        font-size: 2rem;
    }

    .gallery {
        column-count: 2;
        column-gap: 15px;
    }
    
    .gallery-item {
        margin-bottom: 15px;
    }

    main {
        padding: 20px 15px;
    }

    .filter-buttons {
        margin-bottom: 30px;
        gap: 10px;
    }

    .filter-btn {
        padding: 8px 18px;
        font-size: 0.9rem;
    }

    .close {
        top: 20px;
        right: 20px;
        font-size: 35px;
    }

    .modal-content {
        max-width: 95%;
        max-height: 85vh;
    }

    .nav-arrow {
        width: 35px;
        height: 35px;
    }
    
    .nav-arrow::before {
        width: 18px;
        height: 18px;
        border-width: 1.5px;
    }

    .nav-arrow-left {
        left: 15px;
    }

    .nav-arrow-right {
        right: 15px;
    }
}

/* 小屏幕优化 */
@media (max-width: 480px) {
    header {
        padding: 30px 15px;
    }

    header h1 {
        font-size: 1.5rem;
    }

    .gallery {
        column-gap: 10px;
    }
    
    .gallery-item {
        margin-bottom: 10px;
    }
}

/* 底部备案信息 */
footer {
    text-align: center;
    padding: 30px 20px;
    margin-top: 40px;
    border-top: 1px solid #e5e5e5;
    color: #999;
    font-size: 0.85rem;
}

footer a {
    color: #999;
    text-decoration: none;
    transition: color 0.3s ease;
}

footer a:hover {
    color: #666;
}