/* 全局样式 */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    min-height: 100vh;
    color: #333;
}

.container {
    max-width: 1400px;
    margin: 0 auto;
    padding: 20px;
}

/* 导航区域样式 */
.nav-section {
    background: rgba(255, 255, 255, 0.95);
    border-radius: 20px;
    padding: 30px;
    box-shadow: 0 20px 40px rgba(0, 0, 0, 0.1);
    backdrop-filter: blur(10px);
}

.nav-section h1 {
    text-align: center;
    color: #2c3e50;
    margin-bottom: 30px;
    font-size: 2.5em;
    font-weight: 300;
    text-shadow: 0 2px 4px rgba(0, 0, 0, 0.1);
}

.year-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 20px;
    margin-top: 20px;
}

.year-card {
    background: linear-gradient(145deg, #ffffff, #f0f0f0);
    border-radius: 15px;
    padding: 25px;
    text-align: center;
    cursor: pointer;
    transition: all 0.3s ease;
    border: 2px solid transparent;
    box-shadow: 0 8px 16px rgba(0, 0, 0, 0.1);
}

.year-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 15px 30px rgba(0, 0, 0, 0.2);
    border-color: #667eea;
}

.year-card h3 {
    color: #2c3e50;
    margin-bottom: 10px;
    font-size: 1.4em;
    font-weight: 500;
}

.year-card p {
    color: #7f8c8d;
    font-size: 0.9em;
    margin-bottom: 15px;
}

.exam-buttons {
    display: flex;
    gap: 10px;
    justify-content: center;
}

.exam-btn {
    background: linear-gradient(145deg, #667eea, #764ba2);
    color: white;
    border: none;
    padding: 8px 16px;
    border-radius: 8px;
    cursor: pointer;
    font-size: 0.85em;
    transition: all 0.3s ease;
    box-shadow: 0 4px 8px rgba(0, 0, 0, 0.2);
}

.exam-btn:hover {
    transform: translateY(-2px);
    box-shadow: 0 6px 12px rgba(0, 0, 0, 0.3);
}

/* PDF查看区域样式 */
.viewer-section {
    background: rgba(255, 255, 255, 0.95);
    border-radius: 20px;
    padding: 30px;
    box-shadow: 0 20px 40px rgba(0, 0, 0, 0.1);
    backdrop-filter: blur(10px);
    margin-top: 20px;
}

.viewer-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 25px;
    padding-bottom: 15px;
    border-bottom: 2px solid #ecf0f1;
}

.viewer-header h2 {
    color: #2c3e50;
    font-size: 1.8em;
    font-weight: 400;
}

.back-btn {
    background: linear-gradient(145deg, #e74c3c, #c0392b);
    color: white;
    border: none;
    padding: 12px 24px;
    border-radius: 10px;
    cursor: pointer;
    font-size: 1em;
    transition: all 0.3s ease;
    box-shadow: 0 4px 8px rgba(0, 0, 0, 0.2);
}

.back-btn:hover {
    transform: translateY(-2px);
    box-shadow: 0 6px 12px rgba(0, 0, 0, 0.3);
}

/* PDF容器样式 */
.pdf-container {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 30px;
    height: 80vh;
}

.pdf-panel {
    background: #f8f9fa;
    border-radius: 15px;
    overflow: hidden;
    box-shadow: 0 8px 16px rgba(0, 0, 0, 0.1);
    display: flex;
    flex-direction: column;
}

.panel-header {
    background: linear-gradient(145deg, #34495e, #2c3e50);
    color: white;
    padding: 15px 20px;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.panel-header h3 {
    font-size: 1.2em;
    font-weight: 500;
}

.panel-controls {
    display: flex;
    align-items: center;
    gap: 15px;
}

.page-controls {
    display: flex;
    align-items: center;
    gap: 10px;
}

.download-btn {
    background: linear-gradient(145deg, #27ae60, #2ecc71);
    color: white;
    border: none;
    padding: 8px 16px;
    border-radius: 6px;
    cursor: pointer;
    font-size: 0.9em;
    font-weight: 500;
    transition: all 0.3s ease;
    display: flex;
    align-items: center;
    gap: 6px;
    box-shadow: 0 2px 4px rgba(0, 0, 0, 0.2);
}

.download-btn:hover {
    transform: translateY(-1px);
    box-shadow: 0 4px 8px rgba(0, 0, 0, 0.3);
    background: linear-gradient(145deg, #2ecc71, #27ae60);
}

.download-icon {
    font-size: 1.1em;
}

.page-btn {
    background: rgba(255, 255, 255, 0.2);
    color: white;
    border: 1px solid rgba(255, 255, 255, 0.3);
    padding: 6px 12px;
    border-radius: 6px;
    cursor: pointer;
    font-size: 0.9em;
    transition: all 0.3s ease;
}

.page-btn:hover:not(:disabled) {
    background: rgba(255, 255, 255, 0.3);
    transform: translateY(-1px);
}

.page-btn:disabled {
    opacity: 0.5;
    cursor: not-allowed;
}

.page-info {
    font-size: 0.9em;
    font-weight: 500;
    min-width: 60px;
    text-align: center;
}

.pdf-viewer {
    flex: 1;
    overflow: auto;
    padding: 20px;
    background: white;
    position: relative;
}

.pdf-viewer canvas {
    max-width: 100%;
    height: auto;
    box-shadow: 0 4px 8px rgba(0, 0, 0, 0.1);
    border-radius: 8px;
}

.loading {
    display: flex;
    justify-content: center;
    align-items: center;
    height: 200px;
    color: #7f8c8d;
    font-size: 1.1em;
}

.loading::after {
    content: '';
    width: 20px;
    height: 20px;
    border: 2px solid #ecf0f1;
    border-top: 2px solid #667eea;
    border-radius: 50%;
    animation: spin 1s linear infinite;
    margin-left: 10px;
}

@keyframes spin {
    0% { transform: rotate(0deg); }
    100% { transform: rotate(360deg); }
}

/* 响应式设计 */
@media (max-width: 768px) {
    .container {
        padding: 10px;
    }
    
    .nav-section, .viewer-section {
        padding: 20px;
    }
    
    .nav-section h1 {
        font-size: 2em;
    }
    
    .pdf-container {
        grid-template-columns: 1fr;
        height: auto;
    }
    
    .pdf-panel {
        height: 60vh;
    }
    
    .viewer-header {
        flex-direction: column;
        gap: 15px;
        text-align: center;
    }
    
    .panel-controls {
        flex-direction: column;
        gap: 10px;
        align-items: flex-end;
    }
    
    .download-btn {
        padding: 6px 12px;
        font-size: 0.8em;
    }
    
    .year-grid {
        grid-template-columns: repeat(auto-fit, minmax(150px, 1fr));
        gap: 15px;
    }
    
    .year-card {
        padding: 20px;
    }
}

/* 滚动条样式 */
::-webkit-scrollbar {
    width: 8px;
}

::-webkit-scrollbar-track {
    background: #f1f1f1;
    border-radius: 4px;
}

::-webkit-scrollbar-thumb {
    background: linear-gradient(145deg, #667eea, #764ba2);
    border-radius: 4px;
}

::-webkit-scrollbar-thumb:hover {
    background: linear-gradient(145deg, #5a6fd8, #6a4190);
}