:root {
    --primary-color: #007acc;
    --border-color: #ddd;
    --background-light: #f5f5f5;
    --background-white: #fff;
}
body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
    margin: 0;
    background: var(--background-light);
    line-height: 1.6;
}
.container {
    max-width: 1200px;
    margin: 20px auto;
    background: var(--background-white);
    padding: 30px;
    border: 1px solid var(--border-color);
    box-shadow: 0 2px 8px rgba(0, 0, 0, 0.08);
    border-radius: 8px;
}
h1 {
    text-align: center;
    border-bottom: 3px solid var(--primary-color);
    padding-bottom: 15px;
    margin: 0 0 30px 0;
}
.notice {
    background: #fff3cd;
    border-left: 5px solid #f0ad4e;
    padding: 15px 20px;
    margin: 20px 0;
    border-radius: 5px;
}
.controls { 
    margin-bottom: 20px; 
    display: flex; 
    gap: 10px; 
    flex-wrap: wrap;
}
.action-btn {
    background: #6c757d;
    color: white;
    border: none;
    padding: 10px 20px;
    border-radius: 5px;
    cursor: pointer;
    font-weight: bold;
    transition: background-color 0.2s ease;
}
.action-btn:hover { background: #5a6268; }
.category-section {
    margin-bottom: 15px;
    border: 1px solid var(--border-color);
    border-radius: 5px;
    overflow: hidden;
}
.category-header {
    background: #f8f9fa;
    padding: 15px 20px;
    cursor: pointer;
    user-select: none;
    display: flex;
    justify-content: space-between;
    align-items: center;
}
.category-header:hover { background: #e9ecef; }
.category-title { font-size: 18px; font-weight: bold; }
.category-toggle { font-size: 20px; transition: transform 0.3s ease; }
.category-header.active .category-toggle { transform: rotate(180deg); }
.category-content {
    display: none;
    padding: 20px;
    background: #fdfdfd;
    border-top: 1px solid var(--border-color);
}
.category-content.active { display: block; }
.file-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 20px;
}
.file-item {
    border: 1px solid var(--border-color);
    padding: 20px;
    background: #fafafa;
    border-radius: 5px;
    display: flex;
    flex-direction: column;
    transition: all 0.3s ease;
}
.file-item:hover {
    border-color: var(--primary-color);
    transform: translateY(-3px);
    box-shadow: 0 4px 10px rgba(0, 0, 0, 0.1);
}
.file-name { font-size: 16px; font-weight: bold; color: var(--primary-color); margin-bottom: 8px; }
.file-desc { flex-grow: 1; margin-bottom: 10px; }
.file-size { color: #999; font-size: 13px; margin-bottom: 15px; }
.download-link {
    display: block;
    background: var(--primary-color);
    color: white;
    padding: 10px 20px;
    text-decoration: none;
    border-radius: 5px;
    font-weight: bold;
    text-align: center;
}
.download-link:hover { background: #005c99; }
.status {
    background: #e9ecef;
    padding: 15px;
    margin-top: 30px;
    border-radius: 5px;
    text-align: center;
}
@media (max-width: 1024px) { .file-grid { grid-template-columns: repeat(2, 1fr); } }
@media (max-width: 768px) { .container { margin: 10px; padding: 15px; } .file-grid { grid-template-columns: 1fr; } }