/* roulang page: index */
:root {
            --primary: #1E293B;
            --accent: #F97316;
            --darkvariant: #0F172A;
            --surface-light: #F8FAFC;
            --surface-alt: #F1F5F9;
            --text-main: #334155;
            --text-heading: #0F172A;
        }
        body {
            font-family: system-ui, -apple-system, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
            color: var(--text-main);
            background-color: #FFFFFF;
            line-height: 1.75;
            -webkit-font-smoothing: antialiased;
        }
        html {
            scroll-behavior: smooth;
        }
        .text-heading { color: var(--text-heading); }
        .transition-interactive {
            transition: all 0.25s cubic-bezier(0.4, 0, 0.2, 1);
        }