:root {
            --navy: #1a2a44;
            --soft-gray: #f8fafc;
            --accent-green: #10b981;
            --romantic-gold: #d4af37;
            --transition: all 0.4s cubic-bezier(0.4, 0, 0.2, 1);
        }

        body {
            font-family: 'Inter', sans-serif;
            background-color: #ffffff;
            color: #334155;
            scroll-behavior: smooth;
        }

        h1, h2, h3, h4, .serif {
            font-family: 'Merriweather', serif;
        }

        .fade-in {
            animation: fadeIn 0.8s ease-out forwards;
        }

        @keyframes fadeIn {
            from { opacity: 0; transform: translateY(20px); }
            to { opacity: 1; transform: translateY(0); }
        }

        .glossary-card {
            transition: var(--transition);
            border: 1px solid #f1f5f9;
        }

        .glossary-card:hover {
            transform: translateY(-8px);
            box-shadow: 0 25px 50px -12px rgba(0, 0, 0, 0.08);
            border-color: var(--romantic-gold);
        }

        .az-sidebar {
            position: sticky;
            top: 100px;
            max-height: calc(100vh - 120px);
            overflow-y: auto;
        }

        .letter-btn {
            transition: var(--transition);
            width: 38px;
            height: 38px;
            display: flex;
            align-items: center;
            justify-content: center;
            border-radius: 50%;
            font-weight: 600;
            font-size: 0.875rem;
        }

        .letter-btn.active {
            background-color: var(--navy);
            color: white;
            transform: scale(1.1);
        }

        .modal-overlay {
            background: rgba(26, 42, 68, 0.7);
            backdrop-filter: blur(8px);
            display: none;
            position: fixed;
            inset: 0;
            z-index: 100;
            align-items: center;
            justify-content: center;
            padding: 1rem;
        }

        .romantic-button {
            background: var(--navy);
            color: white;
            padding: 14px 28px;
            border-radius: 12px;
            transition: var(--transition);
            display: inline-flex;
            align-items: center;
            gap: 8px;
            cursor: pointer;
            font-weight: 600;
        }

        .romantic-button:hover {
            background: var(--romantic-gold);
            transform: translateY(-2px);
            box-shadow: 0 15px 30px -5px rgba(212, 175, 55, 0.4);
        }

        .nav-link {
            position: relative;
        }

        .nav-link::after {
            content: '';
            position: absolute;
            width: 0;
            height: 2px;
            bottom: -4px;
            left: 0;
            background-color: var(--romantic-gold);
            transition: width 0.3s;
        }

        .nav-link:hover::after {
            width: 100%;
        }

        .search-container {
            box-shadow: 0 10px 40px rgba(0,0,0,0.06);
            border-radius: 60px;
            transition: var(--transition);
            border: 1px solid #f1f5f9;
        }

        .search-container:focus-within {
            box-shadow: 0 15px 50px rgba(0,0,0,0.1);
            transform: scale(1.01);
            border-color: var(--romantic-gold);
        }

        .calc-input {
            width: 100%;
            padding: 16px;
            background: #f8fafc;
            border-radius: 12px;
            border: 1px solid #e2e8f0;
            outline: none;
            transition: all 0.3s;
        }

        .calc-input:focus {
            border-color: var(--romantic-gold);
            background: white;
            box-shadow: 0 0 0 4px rgba(212, 175, 55, 0.1);
        }

        section {
            scroll-margin-top: 100px;
        }

        .knowledge-card {
            background: white;
            border-radius: 24px;
            padding: 40px;
            border: 1px solid #f1f5f9;
            height: 100%;
        }