html { scroll-behavior: smooth; }
        body {
            color: #2C2C2C;
            background-color: #FFFFFF;
            line-height: 1.8;
            font-feature-settings: "palt";
            -webkit-font-smoothing: antialiased;
            -moz-osx-font-smoothing: grayscale;
        }

        .fade-in-up {
            opacity: 0;
            transform: translateY(20px);
            transition: opacity 1s cubic-bezier(0.2, 0.8, 0.2, 1), transform 1s cubic-bezier(0.2, 0.8, 0.2, 1);
        }
        .fade-in-up.is-visible {
            opacity: 1;
            transform: translateY(0);
        }

        #sp-menu { transition: opacity 0.3s ease, visibility 0.3s ease; }
        #sp-menu.hidden-menu { opacity: 0; visibility: hidden; pointer-events: none; }
        #sp-menu.active-menu { opacity: 1; visibility: visible; pointer-events: auto; }

        .separator-line { height: 1px; background-color: #EAE8E3; width: 100%; }

        .btn-solid {
            display: inline-flex;
            align-items: center;
            justify-content: center;
            border: 1px solid #2C2C2C;
            background-color: #2C2C2C;
            color: #FFFFFF;
            padding: 1rem 3rem;
            font-size: 0.875rem;
            letter-spacing: 0.1em;
            transition: all 0.4s ease;
            text-decoration: none;
            width: 100%;
            cursor: pointer;
        }
        .btn-solid:hover {
            background-color: #4A4A4A;
            border-color: #4A4A4A;
        }

        .btn-outline {
            display: inline-flex;
            align-items: center;
            justify-content: center;
            border: 1px solid #2C2C2C;
            background-color: transparent;
            color: #2C2C2C;
            padding: 1rem 3rem;
            font-size: 0.875rem;
            letter-spacing: 0.1em;
            transition: all 0.4s ease;
            text-decoration: none;
            width: 100%;
            cursor: pointer;
        }
        .btn-outline:hover {
            background-color: #2C2C2C;
            color: #FFFFFF;
        }

        /* カート・チェックアウトと同一トンマナ（数量セレクト用） */
        .form-input {
            width: 100%;
            border: 1px solid #EAE8E3;
            background-color: #FFFFFF;
            padding: 0.75rem 1rem;
            font-size: 0.875rem;
            color: #2C2C2C;
            outline: none;
            transition: border-color 0.3s;
        }
        .form-input:focus { border-color: #2C2C2C; }

        .form-select {
            width: 100%;
            border: 1px solid #EAE8E3;
            background-color: #FFFFFF;
            padding: 0.75rem 2.25rem 0.75rem 1rem;
            font-size: 0.875rem;
            color: #2C2C2C;
            outline: none;
            transition: border-color 0.3s;
            appearance: none;
            background-image: url("data:image/svg+xml;charset=UTF-8,%3csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 24 24' fill='none' stroke='%23595959' stroke-width='2' stroke-linecap='round' stroke-linejoin='round'%3e%3cpolyline points='6 9 12 15 18 9'%3e%3c/polyline%3e%3c/svg%3e");
            background-repeat: no-repeat;
            background-position: right 1rem center;
            background-size: 1em;
        }
        .form-select:focus { border-color: #2C2C2C; }

        /* テーブルスタイル */
        .specs-table th {
            width: 30%;
            background-color: #F9F8F6;
            font-weight: 500;
            text-align: left;
            padding: 1.25rem;
            border-bottom: 1px solid #EAE8E3;
            font-size: 0.875rem;
            letter-spacing: 0.08em;
        }
        .specs-table td {
            width: 70%;
            padding: 1.25rem;
            border-bottom: 1px solid #EAE8E3;
            font-size: 0.875rem;
            letter-spacing: 0.08em;
            color: #595959;
            font-weight: 300;
        }

        /* Accordion Style */
        details > summary { list-style: none; }
        details > summary::-webkit-details-marker { display: none; }
        
        /* Thumbnail active state */
        .thumb-active {
            border-color: #2C2C2C !important;
            opacity: 1 !important;
        }

        /* Hide scrollbar */
        .no-scrollbar::-webkit-scrollbar {
            display: none;
        }
        .no-scrollbar {
            -ms-overflow-style: none;  /* IE and Edge */
            scrollbar-width: none;  /* Firefox */
        }