:root {
            --bg-color: #f8fafc;
            --card-blue: linear-gradient(135deg, #60a5fa 0%, #3b82f6 100%);
            --card-pink: linear-gradient(135deg, #f472b6 0%, #ec4899 100%);
            --card-purple: linear-gradient(135deg, #a78bfa 0%, #8b5cf6 100%);
            --text-main: #1e293b;
            --border-color: #e2e8f0;
        }

        body {
            background-color: var(--bg-color);
            font-family: 'Helvetica Neue', Arial, sans-serif;
            margin: 0;
            display: flex;
            flex-direction: column;
            align-items: center;
            min-height: 100vh;
            color: var(--text-main);
            padding: 2rem;
        }

        .container {
            width: 100%;
            max-width: 1000px;
        }

        /* フィルターボタンエリア */
        .buttons-container {
            margin-bottom: 2rem;
        }

        .checkboxes {
            display: flex;
            justify-content: center;
            gap: 10px;
            flex-wrap: wrap;
        }

        .tag-button {
            position: relative;
            padding: 10px 20px;
            border-radius: 8px;
            background: white;
            border: 1px solid var(--border-color);
            cursor: pointer;
            font-size: 14px;
            font-weight: 500;
            transition: all 0.2s ease;
            user-select: none;
        }

        .tag-button:hover {
            border-color: #cbd5e1;
            background-color: #f1f5f9;
        }

        .tag-button input {
            display: none;
        }

        .tag-button .label-text {
            color: #64748b;
            position: relative;
            z-index: 2;
        }

        .tag-button input:checked + .label-text {
            color: white;
        }

        .tag-button .bg-overlay {
            position: absolute;
            top: 0;
            left: 0;
            width: 100%;
            height: 100%;
            background: #334155;
            border-radius: 8px;
            z-index: 1;
            opacity: 0;
            transition: opacity 0.2s ease;
        }

        .tag-button input:checked ~ .bg-overlay {
            opacity: 1;
        }

        /* グリッドコンテナ */
        .box-container {
            display: grid;
            grid-template-columns: repeat(auto-fill, minmax(200px, 1fr));
            gap: 16px;
            width: 100%;
        }

        /* 各アイテム */
        .item {
            aspect-ratio: 4 / 3;
            border-radius: 12px;
            display: flex;
            align-items: center;
            justify-content: center;
            color: white;
            font-weight: bold;
            font-size: 1rem;
            box-shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.1);
        }

        .gradient-blue { background: var(--card-blue); }
        .gradient-pink { background: var(--card-pink); }
        .gradient-purple { background: var(--card-purple); }