:root {
    --primary-color: #3b82f6;
    --bg-color: #f3f4f6;
    --sidebar-bg: #ffffff;
    --card-bg: #ffffff;
    --text-color: #1f2937;
    --text-secondary: #6b7280;
    --border-color: #e5e7eb;
    --hover-bg: #f9fafb;
    --shadow: 0 1px 3px 0 rgba(0, 0, 0, 0.1), 0 1px 2px 0 rgba(0, 0, 0, 0.06);
    --transition: all 0.3s ease;
}

[data-theme="dark"] {
    --primary-color: #60a5fa;
    --bg-color: #111827;
    --sidebar-bg: #1f2937;
    --card-bg: #1f2937;
    --text-color: #f9fafb;
    --text-secondary: #9ca3af;
    --border-color: #374151;
    --hover-bg: #374151;
    --shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.5), 0 2px 4px -1px rgba(0, 0, 0, 0.3);
}

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

body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
    background-color: var(--bg-color);
    color: var(--text-color);
    transition: var(--transition);
    height: 100vh;
    overflow: hidden;
}

.app-container {
    display: flex;
    height: 100%;
}

/* Sidebar Styles */
.sidebar {
    width: 260px;
    background-color: var(--sidebar-bg);
    border-right: 1px solid var(--border-color);
    display: flex;
    flex-direction: column;
    transition: var(--transition);
    z-index: 100;
}

.logo {
    padding: 20px;
    font-size: 1.5rem;
    font-weight: bold;
    color: var(--primary-color);
    display: flex;
    align-items: center;
    gap: 10px;
    border-bottom: 1px solid var(--border-color);
}

.nav-menu {
    flex: 1;
    overflow-y: auto;
    padding: 20px 0;
}

.nav-item {
    padding: 12px 20px;
    cursor: pointer;
    color: var(--text-secondary);
    transition: var(--transition);
    display: flex;
    align-items: center;
    gap: 10px;
    text-decoration: none;
    font-size: 0.95rem;
}

.nav-item:hover, .nav-item.active {
    background-color: var(--hover-bg);
    color: var(--primary-color);
    border-right: 3px solid var(--primary-color);
}

.nav-item i {
    width: 20px;
    text-align: center;
}

/* Main Content Styles */
.main-content {
    flex: 1;
    display: flex;
    flex-direction: column;
    height: 100%;
    overflow: hidden;
}

.header {
    background-color: var(--sidebar-bg);
    padding: 15px 30px;
    border-bottom: 1px solid var(--border-color);
    display: flex;
    justify-content: space-between;
    align-items: center;
    height: 70px;
}

.header-left {
    display: flex;
    align-items: center;
    gap: 15px;
}

.header h1 {
    font-size: 1.25rem;
    font-weight: 600;
}

.header-right {
    display: flex;
    align-items: center;
    gap: 20px;
}

.search-container {
    position: relative;
    width: 300px;
}

.search-icon {
    position: absolute;
    left: 12px;
    top: 50%;
    transform: translateY(-50%);
    color: var(--text-secondary);
}

#search-input {
    width: 100%;
    padding: 10px 10px 10px 35px;
    border-radius: 8px;
    border: 1px solid var(--border-color);
    background-color: var(--bg-color);
    color: var(--text-color);
    outline: none;
    transition: var(--transition);
}

#search-input:focus {
    border-color: var(--primary-color);
    box-shadow: 0 0 0 2px rgba(59, 130, 246, 0.2);
}

.icon-btn {
    background: none;
    border: none;
    cursor: pointer;
    color: var(--text-secondary);
    font-size: 1.2rem;
    padding: 8px;
    border-radius: 50%;
    transition: var(--transition);
    display: flex;
    align-items: center;
    justify-content: center;
}

.icon-btn:hover {
    background-color: var(--hover-bg);
    color: var(--primary-color);
}

.content-area {
    flex: 1;
    overflow-y: auto;
    padding: 30px;
    scroll-behavior: smooth;
}

.category-section {
    margin-bottom: 40px;
    scroll-margin-top: 20px;
}

.category-title {
    font-size: 1.5rem;
    margin-bottom: 20px;
    padding-bottom: 10px;
    border-bottom: 1px solid var(--border-color);
    display: flex;
    align-items: center;
    gap: 10px;
}

.category-title i {
    color: var(--primary-color);
}

.tools-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
    gap: 20px;
}

.tool-card {
    background-color: var(--card-bg);
    border-radius: 12px;
    padding: 20px;
    box-shadow: var(--shadow);
    transition: var(--transition);
    border: 1px solid var(--border-color);
    display: flex;
    flex-direction: column;
    height: 100%;
    cursor: pointer;
    text-decoration: none;
    color: var(--text-color);
}

.tool-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 10px 15px -3px rgba(0, 0, 0, 0.1), 0 4px 6px -2px rgba(0, 0, 0, 0.05);
    border-color: var(--primary-color);
}

.tool-header {
    display: flex;
    align-items: center;
    gap: 15px;
    margin-bottom: 15px;
}

.tool-icon {
    width: 48px;
    height: 48px;
    border-radius: 10px;
    object-fit: cover;
    background-color: var(--bg-color);
}

.tool-info h3 {
    font-size: 1.1rem;
    font-weight: 600;
    margin-bottom: 4px;
}

.tool-tags {
    display: flex;
    gap: 5px;
    flex-wrap: wrap;
}

.tag {
    font-size: 0.75rem;
    padding: 2px 8px;
    border-radius: 4px;
    background-color: var(--bg-color);
    color: var(--text-secondary);
}

.tool-desc {
    font-size: 0.9rem;
    color: var(--text-secondary);
    line-height: 1.5;
    flex: 1;
    display: -webkit-box;
    -webkit-line-clamp: 3;
    -webkit-box-orient: vertical;
    overflow: hidden;
}

.tool-footer {
    margin-top: 15px;
    display: flex;
    justify-content: space-between;
    align-items: center;
    font-size: 0.85rem;
    color: var(--text-secondary);
}

.visit-btn {
    color: var(--primary-color);
    font-weight: 500;
    display: flex;
    align-items: center;
    gap: 5px;
}

.footer {
    padding: 20px;
    text-align: center;
    color: var(--text-secondary);
    border-top: 1px solid var(--border-color);
    background-color: var(--sidebar-bg);
}

/* Mobile Responsive */
.mobile-only {
    display: none;
}

@media (max-width: 768px) {
    .mobile-only {
        display: block;
    }

    .sidebar {
        position: fixed;
        left: -260px;
        top: 0;
        bottom: 0;
        transition: var(--transition);
        box-shadow: var(--shadow);
    }

    .sidebar.open {
        left: 0;
    }

    .search-container {
        width: 150px;
    }
    
    .header {
        padding: 15px;
    }

    .content-area {
        padding: 15px;
    }
}