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

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    line-height: 1.6;
    color: #333;
}

/* Header Styles */
.header {
    background-color: #fff;
    box-shadow: 0 2px 4px rgba(0,0,0,0.1);
    padding: 1rem 0;
    position: fixed;
    width: 100%;
    top: 0;
    z-index: 1000;
}

.header-container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 1rem;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.logo {
    font-size: 1.5rem;
    font-weight: bold;
    color: #2c3e50;
    text-decoration: none;
}

.nav-menu {
    display: flex;
    gap: 2rem;
}

.nav-link {
    color: #2c3e50;
    text-decoration: none;
    font-weight: 500;
    transition: color 0.3s ease;
}

.nav-link:hover {
    color: #3498db;
}

/* Main Content Styles */
.main-container {
    max-width: 1200px;
    margin: 80px auto 0;
    padding: 2rem;
    display: grid;
    grid-template-columns: 250px 1fr;
    gap: 2rem;
}

/* Sidebar Styles */
.sidebar {
    background: #f8f9fa;
    padding: 1rem;
    border-radius: 8px;
    box-shadow: 0 2px 4px rgba(0,0,0,0.05);
}

.category-list {
    list-style: none;
}

.category-item {
    padding: 0.5rem 1rem;
    margin-bottom: 0.5rem;
    border-radius: 4px;
    cursor: pointer;
    transition: background-color 0.3s ease;
}

.category-item:hover {
    background-color: #e9ecef;
}

/* Document List Styles */
.document-list {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
    gap: 1.5rem;
}

.document-card {
    background: #fff;
    border-radius: 8px;
    box-shadow: 0 2px 4px rgba(0,0,0,0.1);
    overflow: hidden;
    transition: transform 0.3s ease;
}

.document-card:hover {
    transform: translateY(-5px);
}

.document-image {
    width: 100%;
    height: 200px;
    object-fit: cover;
}

.document-info {
    padding: 1rem;
}

.document-title {
    font-size: 1.1rem;
    font-weight: 600;
    margin-bottom: 0.5rem;
}

.document-meta {
    font-size: 0.9rem;
    color: #6c757d;
    margin-bottom: 0.5rem;
}

.document-description {
    font-size: 0.9rem;
    color: #495057;
    margin-bottom: 1rem;
}

/* Button Styles */
.btn {
    padding: 0.5rem 1rem;
    border-radius: 4px;
    border: none;
    cursor: pointer;
    font-weight: 500;
    transition: background-color 0.3s ease;
}

.btn-primary {
    background-color: #3498db;
    color: #fff;
}

.btn-primary:hover {
    background-color: #2980b9;
}

.btn-secondary {
    background-color: #6c757d;
    color: #fff;
}

.btn-secondary:hover {
    background-color: #5a6268;
}

/* Form Styles */
.form-group {
    margin-bottom: 1rem;
}

.form-label {
    display: block;
    margin-bottom: 0.5rem;
    font-weight: 500;
}

.form-control {
    width: 100%;
    padding: 0.5rem;
    border: 1px solid #ced4da;
    border-radius: 4px;
    font-size: 1rem;
}

.form-control:focus {
    outline: none;
    border-color: #3498db;
    box-shadow: 0 0 0 2px rgba(52,152,219,0.2);
}

/* Responsive Design */
@media (max-width: 768px) {
    .main-container {
        grid-template-columns: 1fr;
    }

    .nav-menu {
        display: none;
    }

    .document-list {
        grid-template-columns: 1fr;
    }
}