/* roulang page: index */
:root {
            --color-primary: #0A3A6B;
            --color-secondary: #00B4D8;
            --color-dark: #0B0F19;
            --color-bg-light: #F4F6F9;
            --color-text-main: #1E293B;
            --color-text-muted: #64748B;
            --color-border: #E2E8F0;
        }
        body {
            font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "PingFang SC", "Microsoft YaHei", sans-serif;
            background-color: var(--color-bg-light);
            color: var(--color-text-main);
            line-height: 1.75;
            box-sizing: border-box;
        }
        .section-alt {
            background-color: #FFFFFF;
            border-top: 1px solid var(--color-border);
            border-bottom: 1px solid var(--color-border);
        }
        .section-dark {
            background-color: var(--color-dark);
            color: #E2E8F0;
        }
        details summary::-webkit-details-marker {
            display: none;
        }
        .smooth-transition {
            transition: all 0.25s ease-in-out;
        }