:root {
    --primary-color: #2c3e50;
    --secondary-color: #34495e;
    --background-color: #f8f9fa;
    --text-color: #333;
    --border-radius: 8px;
    --transition: all 0.3s ease;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, 'Open Sans', 'Helvetica Neue', sans-serif;
    line-height: 1.6;
    max-width: 1200px;
    margin: 0 auto;
    padding: 20px;
    color: var(--text-color);
    background-color: #fff;
}

header {
    text-align: center;
    margin-bottom: 40px;
    padding: 20px;
    background: linear-gradient(to right, var(--primary-color), var(--secondary-color));
    color: white;
    border-radius: var(--border-radius);
    position: relative;
}

h1 {
    font-size: 2.5em;
    margin-bottom: 20px;
    text-shadow: 2px 2px 4px rgba(0,0,0,0.2);
}

.top-left-logo {
    position: absolute;
    top: 15px;
    left: 15px;
    height: 40px;
    object-fit: contain;
    z-index: 1000;
}

.subtitle {
    color: rgba(255,255,255,0.9);
    margin-bottom: 20px;
}

.affiliation {
    margin-bottom: 20px;
}

.links {
    margin: 20px 0;
    display: flex;
    justify-content: center;
    gap: 20px;
}

.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    padding: 12px 30px;
    background-color: rgba(255,255,255,0.15);
    color: white;
    text-decoration: none;
    border-radius: var(--border-radius);
    transition: var(--transition);
    border: 2px solid rgba(255,255,255,0.3);
    font-weight: 500;
    font-size: 1.1em;
    min-width: 120px;
    position: relative;
    overflow: hidden;
}

.btn::before {
    content: '';
    position: absolute;
    top: 0;
    left: -100%;
    width: 100%;
    height: 100%;
    background: linear-gradient(
        120deg,
        transparent,
        rgba(255,255,255,0.2),
        transparent
    );
    transition: 0.5s;
}

.btn:hover {
    background-color: rgba(255,255,255,0.25);
    transform: translateY(-2px);
    box-shadow: 0 5px 15px rgba(0,0,0,0.2);
    border-color: rgba(255,255,255,0.5);
}

.btn:hover::before {
    left: 100%;
}

.btn:active {
    transform: translateY(0);
    box-shadow: 0 2px 8px rgba(0,0,0,0.2);
}

section {
    margin-bottom: 40px;
    padding: 20px;
    background-color: white;
    border-radius: var(--border-radius);
    box-shadow: 0 2px 4px rgba(0,0,0,0.1);
}

.abstract {
    background-color: var(--background-color);
    padding: 30px;
    border-radius: var(--border-radius);
    margin-bottom: 40px;
}

.preview-tabs {
    display: flex;
    justify-content: center;
    margin-bottom: 20px;
    gap: 10px;
}

.tab-btn {
    padding: 12px 24px;
    border: none;
    background-color: var(--background-color);
    cursor: pointer;
    border-radius: var(--border-radius);
    transition: var(--transition);
    font-weight: 500;
}

.tab-btn:hover {
    background-color: #e9ecef;
}

.tab-btn.active {
    background-color: var(--primary-color);
    color: white;
}

.preview-content {
    position: relative;
    padding: 20px;
    background-color: var(--background-color);
    border-radius: var(--border-radius);
}

.preview-item {
    display: none;
    text-align: center;
}

.preview-item.active {
    display: block;
    animation: fadeIn 0.5s ease;
}

.preview-item h3 {
    color: var(--primary-color);
    margin: 20px 0 10px;
}

.preview-item img {
    max-width: 20%;
    height: auto;
    border-radius: var(--border-radius);
    margin: 10px auto;
    box-shadow: 0 4px 6px rgba(0,0,0,0.1);
    transition: var(--transition);
    display: block;
}

.preview-item img:hover {
    transform: scale(1.1);
    box-shadow: 0 6px 8px rgba(0,0,0,0.15);
}

.note {
    font-size: 0.9em;
    color: #666;
    text-align: center;
    margin-top: 20px;
    padding: 10px;
    background-color: #fff3cd;
    border-radius: var(--border-radius);
}

.download-section {
    background-color: var(--background-color);
    padding: 30px;
    border-radius: var(--border-radius);
}

.download-section h2 {
    text-align: center;
    margin-bottom: 30px;
    color: var(--primary-color);
}

.download-section h3 {
    color: var(--primary-color);
    margin-bottom: 20px;
    padding-bottom: 10px;
    border-bottom: 2px solid var(--primary-color);
}

.download-grid {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 15px;
    margin-bottom: 40px;
}

.download-item {
    background-color: white;
    padding: 15px;
    border-radius: var(--border-radius);
    text-align: center;
    box-shadow: 0 2px 4px rgba(0,0,0,0.1);
    transition: var(--transition);
    cursor: pointer;
}

.download-item:hover {
    transform: translateY(-2px);
    box-shadow: 0 4px 8px rgba(0,0,0,0.15);
}

.sampled-grid {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 20px;
}

.sampled-group {
    background-color: white;
    padding: 20px;
    border-radius: var(--border-radius);
    box-shadow: 0 2px 4px rgba(0,0,0,0.1);
    text-align: center;
}

.sampled-group h4 {
    color: var(--primary-color);
    margin-bottom: 15px;
    font-size: 1.1em;
}

.sampled-links {
    display: flex;
    gap: 20px;
    justify-content: center;
}

.text-link {
    color: var(--primary-color);
    text-decoration: underline;
    transition: var(--transition);
}

.text-link:hover {
    color: var(--secondary-color);
}

@media (max-width: 768px) {
    .download-grid {
        grid-template-columns: repeat(2, 1fr);
    }
    
    .sampled-grid {
        grid-template-columns: repeat(2, 1fr);
    }
    
    .sampled-links {
        flex-direction: row;
        gap: 20px;
    }
}

.bibtex {
    background-color: var(--background-color);
    padding: 30px;
    border-radius: var(--border-radius);
}

.bibtex pre {
    background-color: var(--primary-color);
    color: #fff;
    padding: 20px;
    border-radius: var(--border-radius);
    overflow-x: auto;
    font-family: 'Courier New', Courier, monospace;
}

.license, .contact {
    text-align: center;
    padding: 20px;
    background-color: var(--background-color);
    border-radius: var(--border-radius);
}

footer {
    text-align: center;
    margin-top: 50px;
    padding: 20px;
    border-top: 1px solid #dee2e6;
    color: #6c757d;
}

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

.teaser-image {
    text-align: center;
    margin: 40px 0;
    padding: 0;
    background: none;
    box-shadow: none;
}

.teaser-image img {
    max-width: 100%;
    height: auto;
    border-radius: var(--border-radius);
    box-shadow: 0 4px 8px rgba(0,0,0,0.1);
}

@media (max-width: 768px) {
    body {
        padding: 10px;
    }
    
    h1 {
        font-size: 2em;
    }
    
    .preview-tabs {
        flex-direction: column;
    }
    
    .tab-btn {
        margin: 5px 0;
    }
    
    .links {
        flex-direction: column;
        gap: 10px;
    }
    
    .btn {
        width: 100%;
        max-width: 300px;
        margin: 0 auto;
    }
    
    .teaser-image {
        margin: 20px 0;
    }
}

.language-switch {
    position: absolute;
    top: 15px;
    right: 15px;
    display: flex;
    gap: 5px;
}

.lang-btn {
    padding: 4px 8px;
    border: 1px solid rgba(255, 255, 255, 0.5);
    background-color: transparent;
    color: white;
    border-radius: 4px;
    cursor: pointer;
    transition: var(--transition);
    font-size: 0.9em;
    font-weight: 500;
    line-height: 1;
}

.lang-btn.active {
    background-color: rgba(255, 255, 255, 0.2);
    border-color: white;
}

.lang-btn:hover {
    background-color: rgba(255, 255, 255, 0.3);
    transform: translateY(-1px);
}

@media (max-width: 768px) {
    .language-switch {
        top: 10px;
        right: 10px;
    }
    
    .lang-btn {
        padding: 3px 6px;
        font-size: 0.8em;
    }
}

/* 语言切换相关样式 */
.zh, .en {
    display: none;
}

.zh.active, .en.active {
    display: block;
}

/* 在中文模式下显示中文内容 */
html[lang="zh"] .zh {
    display: block;
}

/* 在英文模式下显示英文内容 */
html[lang="en"] .en {
    display: block;
}

.checkpoint-section {
    background-color: var(--background-color);
    padding: 30px;
    border-radius: var(--border-radius);
    margin-bottom: 40px;
}

.checkpoint-section h2 {
    text-align: center;
    margin-bottom: 30px;
    color: var(--primary-color);
}

.checkpoint-grid {
    display: grid;
    grid-template-columns: repeat(5, 1fr);
    gap: 20px;
}

.checkpoint-group {
    background-color: white;
    padding: 20px;
    border-radius: var(--border-radius);
    box-shadow: 0 2px 4px rgba(0,0,0,0.1);
    text-align: center;
}

.checkpoint-group h3 {
    color: var(--primary-color);
    margin-bottom: 15px;
    font-size: 1.2em;
}

.checkpoint-links {
    display: flex;
    flex-wrap: wrap;
    gap: 15px;
    justify-content: center;
}

.checkpoint-links .text-link {
    font-size: 0.95em;
}

.download-item {
    display: block; 
    text-decoration: none;
    color: inherit;
}

.text-link {
    color: var(--primary-color);
    text-decoration: underline;
    transition: var(--transition);
    display: inline; 
}

.bibtex h2 {
    text-align: center;
}

.checkpoint-grid-5 {
  display: grid;
  grid-template-columns: repeat(5, 1fr); 
  gap: 15px;
}

@media (max-width: 768px) {
    .checkpoint-grid {
        grid-template-columns: repeat(2, 1fr);
    }
    
	.checkpoint-grid-5 {
	    grid-template-columns: repeat(2, 1fr);
	}
	  
    .checkpoint-group {
        padding: 15px;
    }
    
    .checkpoint-links {
        gap: 10px;
    }
}