/* roulang page: index */
:root {
            --color-primary: #0B332E;
            --color-primary-dark: #08201D;
            --color-accent: #C68A4C;
            --color-surface: #F8F9FA;
            --text-main: #0F172A;
            --text-muted: #475569;
            --border-light: #E2E8F0;
        }

        html {
            scroll-behavior: smooth;
            -webkit-text-size-adjust: 100%;
        }

        body {
            color: var(--text-main);
            background-color: var(--color-surface);
            line-height: 1.65;
            overflow-x: hidden;
        }

        .hero-banner-bg {
            background-image: linear-gradient(rgba(11, 51, 46, 0.92), rgba(8, 32, 29, 0.95)), url('/assets/images/4794a8ffbcbb2cc4.webp');
            background-size: cover;
            background-position: center;
        }

        .dark-strip-bg {
            background-image: linear-gradient(rgba(8, 32, 29, 0.95), rgba(8, 32, 29, 0.98)), url('/assets/images/7f3ce6743182318b.webp');
            background-size: cover;
            background-position: center;
        }

        .guarantee-bg {
            background-image: linear-gradient(rgba(248, 249, 250, 0.96), rgba(241, 244, 243, 0.98)), url('/assets/images/6df09540423d8bf9.webp');
            background-size: cover;
            background-position: center;
        }

        .stat-card-gradient {
            background: linear-gradient(145deg, #ffffff 0%, #f9fbfb 100%);
            box-shadow: 0 4px 20px -2px rgba(11, 51, 46, 0.06);
        }

        .course-card {
            transition: transform 0.25s cubic-bezier(0.16, 1, 0.3, 1), box-shadow 0.25s ease;
        }
        .course-card:hover {
            transform: translateY(-4px);
            box-shadow: 0 16px 32px -4px rgba(11, 51, 46, 0.12);
        }

        details summary::-webkit-details-marker {
            display: none;
        }