/* roulang page: index */
:root {
            --color-primary: #0F172A;
            --color-volt: #10B981;
            --color-volt-hover: #059669;
            --color-accent: #F97316;
            --color-surface: #FFFFFF;
            --color-bg-subtle: #F8FAFC;
            --color-border: #E2E8F0;
            --radius-md: 0.75rem;
            --radius-lg: 1.25rem;
            --shadow-soft: 0 10px 30px -5px rgba(15, 23, 42, 0.05);
            --shadow-hover: 0 20px 40px -10px rgba(15, 23, 42, 0.12);
        }

        body {
            background-color: var(--color-bg-subtle);
            color: var(--color-primary);
            line-height: 1.75;
            overflow-x: hidden;
            -webkit-font-smoothing: antialiased;
        }

        .section-separator {
            border-bottom: 1px solid rgba(226, 232, 240, 0.8);
        }

        .card-custom {
            background: #ffffff;
            border: 1px solid var(--color-border);
            border-radius: var(--radius-lg);
            transition: all 0.28s cubic-bezier(0.4, 0, 0.2, 1);
        }

        .card-custom:hover {
            transform: translateY(-4px);
            box-shadow: var(--shadow-hover);
            border-color: rgba(16, 185, 129, 0.4);
        }

        .btn-volt {
            background-color: var(--color-volt);
            color: #0F172A;
            font-weight: 700;
            transition: all 0.2s ease;
            box-shadow: 0 4px 14px 0 rgba(16, 185, 129, 0.35);
        }

        .btn-volt:hover {
            background-color: #22C55E;
            transform: translateY(-1px);
            box-shadow: 0 6px 20px 0 rgba(16, 185, 129, 0.45);
        }

        .btn-outline-dark {
            border: 1.5px solid #0F172A;
            color: #0F172A;
            font-weight: 600;
            transition: all 0.2s ease;
        }

        .btn-outline-dark:hover {
            background-color: #0F172A;
            color: #ffffff;
        }

        .badge-volt {
            background-color: rgba(16, 185, 129, 0.12);
            color: #047857;
            border: 1px solid rgba(16, 185, 129, 0.25);
        }

        .grid-pattern {
            background-image: radial-gradient(rgba(15, 23, 42, 0.07) 1px, transparent 1px);
            background-size: 24px 24px;
        }

        /* Accordion transition utility */
        .faq-content {
            max-height: 0;
            overflow: hidden;
            transition: max-height 0.35s cubic-bezier(0, 1, 0, 1);
        }

        .faq-item.active .faq-content {
            max-height: 400px;
            transition: max-height 0.45s ease-in-out;
        }

        .faq-item.active .faq-icon {
            transform: rotate(180deg);
        }