:root {
            --primary-blue: #0d6efd;
            --light-gray: #f8f9fa;
            --dark-gray: #343a40;
            --text-muted: #6c757d;
        }

        body {
            font-family: 'Poppins', sans-serif;
            background-color: var(--light-gray);
        }

        /* --- Header & Hero Section --- */
        .hero-section {
            background-color: #fff;
            padding: 5rem 0;
            text-align: center;
            border-bottom: 1px solid #dee2e6;
        }
        .hero-section .display-5 {
            font-weight: 700;
            color: var(--dark-gray);
        }
        .hero-section .lead {
            max-width: 700px;
            margin: 1rem auto 2rem auto;
            color: var(--text-muted);
        }
        .search-bar {
            max-width: 600px;
            margin: 0 auto;
        }
        .search-bar .form-control {
            padding: 0.9rem 1.25rem;
            border-radius: 50px;
            border-color: #ced4da;
        }
        .search-bar .btn {
            border-radius: 50px;
            padding: 0.9rem 1.5rem;
        }

        /* --- Ad Placeholders --- */
        .ad-placeholder {
            background-color: #e9ecef;
            display: flex;
            align-items: center;
            justify-content: center;
            text-align: center;
            color: #adb5bd;
            border-radius: 0.375rem;
            font-size: 0.9rem;
            font-weight: 500;
        }
        .ad-placeholder-leaderboard {
            height: 90px;
            margin: 2rem auto;
        }
        .ad-placeholder-skyscraper {
            height: 600px; /* Standard skyscraper height */
        }
        
        /* --- Tool Grid Section --- */
        .tool-category-title {
            font-weight: 600;
            color: var(--dark-gray);
            margin-bottom: 1.5rem;
        }
        .tool-card {
            background-color: #fff;
            border: 1px solid #e9ecef;
            border-radius: 0.5rem;
            padding: 1.5rem;
            text-align: center;
            text-decoration: none;
            color: var(--dark-gray);
            transition: transform 0.2s ease, box-shadow 0.2s ease;
            height: 100%;
        }
        .tool-card:hover {
            transform: translateY(-5px);
            box-shadow: 0 8px 25px rgba(0,0,0,0.07);
            color: var(--primary-blue);
        }
        .tool-card .icon {
            font-size: 2.5rem;
            margin-bottom: 1rem;
            color: var(--primary-blue);
        }
        .tool-card .tool-name {
            font-weight: 600;
            font-size: 1.1rem;
        }
        .tool-card .tool-description {
            font-size: 0.85rem;
            color: var(--text-muted);
        }

        /* --- Footer --- */
        .footer {
            background-color: #fff;
            padding: 3rem 0;
            margin-top: 4rem;
            border-top: 1px solid #dee2e6;
        }
        .footer .brand-text {
            font-weight: 600;
        }
        .footer .footer-link {
            text-decoration: none;
            color: var(--text-muted);
            transition: color 0.2s;
        }
        .footer .footer-link:hover {
            color: var(--primary-blue);
        }