:root {
            --primary-bg: linear-gradient(135deg, #bed0e2, #a3bee2);
            --card-bg: rgba(255, 255, 255, 0.9);
            --text-color: #0f172a;
            --input-bg: #ffffff;
            --input-border: #cbd5e1;
            --accent-color: #2563eb;
            --button-glow: 0 4px 12px rgba(37, 99, 235, 0.3);
            --neon-glow: 0 0 10px #98b8ec, 0 0 20px #a2bde9, 0 0 30px #2563eb;
            --neon-glow-dark: 0 0 10px #60a5fa, 0 0 20px #60a5fa, 0 0 30px #3b82f6;
        }
        .dark {
            --primary-bg: linear-gradient(135deg, #1e293b, #0f172a);
            --card-bg: rgba(30, 41, 59, 0.95);
            --text-color: #e2e8f0;
            --input-bg: #1e293b;
            --input-border: #475569;
            --accent-color: #3b82f6;
            --button-glow: 0 4px 12px rgba(59, 130, 246, 0.5);
            --neon-glow: 0 0 10px #60a5fa, 0 0 20px #60a5fa, 0 0 30px #3b82f6;
        }
        body {
            background: var(--primary-bg);
            color: var(--text-color);
            font-family: 'Inter', sans-serif;
            transition: all 0.3s ease-in-out;
            -webkit-tap-highlight-color: transparent;
        }
        .card {
            background: var(--card-bg);
            backdrop-filter: blur(12px);
            border-radius: 16px;
            box-shadow: 0 8px 24px rgba(0, 0, 0, 0.1), var(--neon-glow);
            transition: transform 0.3s ease, box-shadow 0.3s ease;
        }
        .card:hover {
            transform: translateY(-6px);
            box-shadow: 0 12px 32px rgba(0, 0, 0, 0.15), var(--neon-glow);
        }
        input, select {
            background: var(--input-bg);
            border: 1px solid var(--input-border);
            border-radius: 8px;
            padding: 12px;
            font-size: 16px;
            transition: border-color 0.3s ease, box-shadow 0.3s ease;
            width: 100%;
            box-sizing: border-box;
        }
        input:focus, select:focus {
            border-color: var(--accent-color);
            box-shadow: var(--neon-glow);
            outline: none;
        }
        button {
            border-radius: 8px;
            padding: 12px 16px;
            font-weight: 500;
            font-size: 16px;
            transition: transform 0.2s ease, box-shadow 0.3s ease, background-color 0.2s ease;
            touch-action: manipulation;
            min-height: 48px;
            box-shadow: var(--neon-glow);
        }
        button:hover {
            transform: translateY(-2px);
            box-shadow: var(--neon-glow-dark);
        }
        .tooltip {
            position: relative;
        }
        .tooltip:hover::after {
            content: attr(data-tooltip);
            position: absolute;
            bottom: 120%;
            left: 50%;
            transform: translateX(-50%);
            background: var(--accent-color);
            color: white;
            padding: 8px 12px;
            border-radius: 6px;
            font-size: 14px;
            font-weight: 500;
            white-space: nowrap;
            z-index: 10;
            opacity: 0;
            animation: fadeIn 0.2s ease forwards;
            box-shadow: var(--neon-glow);
        }
        @keyframes fadeIn {
            to { opacity: 1; }
        }
        @media (max-width: 768px) {
            .container {
                padding: 12px;
            }
            .grid-cols-2, .grid-cols-4 {
                grid-template-columns: 1fr;
            }
            input, select, button {
                font-size: 14px;
                padding: 10px;
                margin-bottom: 12px;
            }
            .flex.gap-4 {
                flex-direction: column;
                gap: 12px;
            }
            .tooltip:hover::after {
                font-size: 12px;
                padding: 6px 10px;
            }
            h1 {
                font-size: 1.75rem;
            }
            h2 {
                font-size: 1.25rem;
            }
            #expenseChart {
                max-height: 300px;
            }
            .card {
                padding: 16px;
                box-shadow: 0 8px 24px rgba(0, 0, 0, 0.1), var(--neon-glow);
            }
            #expenseList {
                max-height: 400px;
            }
        }
        @media (max-width: 480px) {
            input, select, button {
                font-size: 12px;
                padding: 8px;
            }
            button {
                min-height: 44px;
                box-shadow: var(--neon-glow);
            }
            .tooltip:hover::after {
                font-size: 10px;
                padding: 4px 8px;
            }
            h1 {
                font-size: 1.5rem;
            }
            h2 {
                font-size: 1.125rem;
            }
            .card {
                padding: 12px;
                box-shadow: 0 8px 24px rgba(0, 0, 0, 0.1), var(--neon-glow);
            }
        }
        #expenseList, #itemList {
            -webkit-overflow-scrolling: touch;
        }
        canvas#expenseChart {
            width: 100% !important;
            height: auto !important;
            max-height: 400px;
        }