/* roulang page: index */
:root {
            --primary: #1E3A8A;
            --primary-light: #3B82F6;
            --accent: #F97316;
            --accent-cyan: #06B6D4;
            --surface: #F8FAFC;
            --text-main: #0F172A;
            --text-muted: #475569;
        }
        body {
            font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, "Noto Sans SC", sans-serif;
            background-color: var(--surface);
            color: var(--text-muted);
            overflow-x: hidden;
        }
        .hero-clip {
            clip-path: polygon(0 0, 100% 0, 100% 92%, 0 100%);
        }
        .hero-tilt {
            transform: perspective(1000px) rotateY(-4deg) rotateX(2deg);
            transition: transform 0.4s ease;
        }
        .hero-tilt:hover {
            transform: perspective(1000px) rotateY(0deg) rotateX(0deg);
        }
        .card-shadow {
            box-shadow: 0 10px 25px -5px rgba(15, 23, 42, 0.04), 0 8px 10px -6px rgba(15, 23, 42, 0.04);
            transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
        }
        .card-shadow:hover {
            transform: translateY(-4px);
            box-shadow: 0 20px 30px -10px rgba(30, 58, 138, 0.12), 0 10px 15px -5px rgba(30, 58, 138, 0.08);
        }
        html {
            scroll-behavior: smooth;
        }
        details > summary::-webkit-details-marker {
            display: none;
        }
        details[open] summary svg {
            transform: rotate(180deg);
        }