/* roulang page: index */
:root {
            --primary-deep: #0B3D3A;
            --accent-bright: #00C9A7;
            --bg-dark: #121212;
            --card-bg: rgba(26, 42, 40, 0.6);
            --text-primary: #F0F4F3;
            --text-secondary: #9BAEAB;
            --text-highlight: #00C9A7;
            --border-subtle: rgba(0, 201, 167, 0.15);
            --border-active: rgba(0, 201, 167, 0.4);
            --shadow-card: 0 8px 32px rgba(0, 0, 0, 0.4);
            --shadow-card-hover: 0 12px 40px rgba(0, 201, 167, 0.15);
            --radius-card: 16px;
            --radius-btn: 12px;
            --radius-input: 8px;
            --spacing-section: 120px;
            --spacing-element: 24px;
        }

        * {
            box-sizing: border-box;
            margin: 0;
            padding: 0;
        }

        html {
            scroll-behavior: smooth;
        }

        body {
            font-family: "PingFang SC", "Microsoft YaHei", "Helvetica Neue", sans-serif;
            background-color: var(--bg-dark);
            color: var(--text-secondary);
            line-height: 1.6;
            font-size: 16px;
            -webkit-font-smoothing: antialiased;
            -moz-osx-font-smoothing: grayscale;
            overflow-x: hidden;
            padding-bottom: 70px;
        }

        .grid-container {
            max-width: 1200px;
            padding-left: 20px;
            padding-right: 20px;
        }

        h1, h2, h3, h4, h5, h6 {
            color: var(--text-primary);
            font-weight: 600;
            letter-spacing: 0.3px;
        }

        h1 {
            font-size: 32px;
            line-height: 1.25;
            font-weight: 700;
            letter-spacing: 0.5px;
        }
        h2 {
            font-size: 24px;
            line-height: 1.33;
            margin-bottom: 20px;
        }
        h3 {
            font-size: 20px;
            line-height: 1.4;
            margin-bottom: 12px;
        }

        a {
            color: var(--accent-bright);
            text-decoration: none;
            transition: color 0.25s ease, text-decoration 0.25s ease;
        }
        a:hover {
            color: #00FFD2;
            text-decoration: underline;
        }

        img {
            max-width: 100%;
            height: auto;
            display: block;
        }

        button, .button {
            font-family: inherit;
            cursor: pointer;
            transition: all 0.25s ease;
        }

        .btn-primary {
            background: var(--accent-bright);
            color: var(--primary-deep);
            font-weight: 600;
            letter-spacing: 1px;
            font-size: 16px;
            padding: 14px 32px;
            border-radius: var(--radius-btn);
            border: none;
            display: inline-flex;
            align-items: center;
            justify-content: center;
            gap: 8px;
            box-shadow: 0 4px 12px rgba(0, 201, 167, 0.3);
        }
        .btn-primary:hover {
            background: #00FFD2;
            box-shadow: 0 0 24px rgba(0, 201, 167, 0.6);
            transform: scale(1.03);
            color: var(--primary-deep);
            text-decoration: none;
        }

        .btn-secondary {
            background: transparent;
            border: 1px solid var(--accent-bright);
            color: var(--accent-bright);
            font-weight: 600;
            letter-spacing: 0.8px;
            font-size: 16px;
            padding: 12px 28px;
            border-radius: var(--radius-btn);
            display: inline-flex;
            align-items: center;
            justify-content: center;
            gap: 6px;
        }
        .btn-secondary:hover {
            background: rgba(0, 201, 167, 0.1);
            color: #00FFD2;
            border-color: #00FFD2;
            text-decoration: none;
        }

        /* Header & Navigation */
        .header-desktop {
            position: fixed;
            top: 0;
            left: 0;
            width: 100%;
            z-index: 100;
            background: rgba(11, 61, 58, 0.85);
            backdrop-filter: blur(12px);
            -webkit-backdrop-filter: blur(12px);
            border-bottom: 1px solid rgba(0, 201, 167, 0.2);
            display: block;
        }

        .nav-container {
            display: flex;
            align-items: center;
            justify-content: space-between;
            max-width: 1200px;
            margin: 0 auto;
            padding: 0 24px;
            height: 70px;
        }

        .logo {
            font-weight: 700;
            font-size: 24px;
            letter-spacing: 2px;
            color: var(--accent-bright);
            text-decoration: none;
            display: flex;
            align-items: center;
            gap: 4px;
        }
        .logo:hover {
            color: #00FFD2;
            text-decoration: none;
        }

        .nav-links {
            display: flex;
            align-items: center;
            gap: 32px;
            list-style: none;
            margin: 0;
        }

        .nav-links a {
            color: var(--text-secondary);
            font-weight: 500;
            font-size: 16px;
            padding: 8px 0;
            border-bottom: 2px solid transparent;
            transition: color 0.2s, border-color 0.2s;
        }
        .nav-links a:hover {
            color: var(--text-primary);
            border-bottom-color: var(--accent-bright);
            text-decoration: none;
        }

        .mobile-bottom-nav {
            display: none;
            position: fixed;
            bottom: 0;
            left: 0;
            width: 100%;
            background: #0B3D3A;
            backdrop-filter: blur(8px);
            border-top: 1px solid rgba(0, 201, 167, 0.25);
            z-index: 100;
            padding: 8px 16px;
            justify-content: space-around;
            align-items: center;
        }

        .mobile-tab {
            display: flex;
            flex-direction: column;
            align-items: center;
            color: var(--text-secondary);
            font-size: 12px;
            gap: 4px;
            text-decoration: none;
            transition: color 0.2s;
            font-weight: 500;
        }
        .mobile-tab i {
            font-size: 20px;
        }
        .mobile-tab.active, .mobile-tab:hover {
            color: var(--accent-bright);
            text-decoration: none;
        }

        .hero-section {
            min-height: 100vh;
            display: flex;
            align-items: center;
            justify-content: center;
            position: relative;
            background: radial-gradient(circle at 30% 40%, #0B3D3A 0%, #121212 70%);
            overflow: hidden;
            padding: 100px 20px 60px;
        }

        .hero-bg-effect {
            position: absolute;
            top: 0;
            left: 0;
            width: 100%;
            height: 100%;
            background-image: url('/assets/images/backpic/back-1.webp');
            background-size: cover;
            background-position: center;
            opacity: 0.25;
            z-index: 0;
            filter: brightness(0.8) contrast(1.1);
        }

        .hero-content {
            position: relative;
            z-index: 2;
            text-align: center;
            max-width: 800px;
        }

        .hero-content h1 {
            font-size: 40px;
            font-weight: 700;
            margin-bottom: 20px;
            line-height: 1.3;
        }

        .glass-card {
            background: rgba(26, 42, 40, 0.6);
            backdrop-filter: blur(16px);
            -webkit-backdrop-filter: blur(16px);
            border: 1px solid var(--border-subtle);
            border-radius: var(--radius-card);
            box-shadow: var(--shadow-card);
            padding: var(--spacing-element);
            transition: transform 0.3s ease, box-shadow 0.3s ease;
        }
        .glass-card:hover {
            transform: translateY(-4px);
            box-shadow: var(--shadow-card-hover);
        }

        .section-spacing {
            margin-top: var(--spacing-section);
            margin-bottom: var(--spacing-section);
        }

        .icon-accent {
            color: var(--accent-bright);
            font-size: 2rem;
            margin-bottom: 12px;
        }

        .stat-number {
            font-size: 36px;
            font-weight: 700;
            color: var(--accent-bright);
            line-height: 1.2;
        }

        .accordion-title {
            background: rgba(26, 42, 40, 0.8);
            border: 1px solid var(--border-subtle);
            border-radius: var(--radius-card);
            padding: 16px 20px;
            font-size: 18px;
            font-weight: 500;
            color: var(--text-primary);
            cursor: pointer;
            transition: background 0.2s;
            display: flex;
            align-items: center;
            gap: 12px;
        }
        .accordion-title:hover {
            background: rgba(26, 42, 40, 0.9);
        }
        .accordion-content {
            background: rgba(26, 42, 40, 0.4);
            border-left: 3px solid var(--accent-bright);
            padding: 16px 20px;
            margin-top: 4px;
            border-radius: 0 8px 8px 0;
        }

        footer {
            background: #0A1F1D;
            padding: 60px 0 30px;
            color: var(--text-secondary);
        }

        @media screen and (max-width: 1024px) {
            .nav-links {
                gap: 20px;
            }
            h1 {
                font-size: 28px;
            }
            .section-spacing {
                margin-top: 80px;
                margin-bottom: 80px;
            }
        }

        @media screen and (max-width: 640px) {
            .header-desktop {
                display: block;
            }
            .nav-container {
                padding: 0 16px;
                height: 60px;
            }
            .nav-links {
                display: none;
            }
            .mobile-bottom-nav {
                display: flex;
            }
            body {
                padding-bottom: 80px;
            }
            .hero-content h1 {
                font-size: 28px;
            }
            .section-spacing {
                margin-top: 60px;
                margin-bottom: 60px;
            }
            .grid-x .cell {
                margin-bottom: 20px;
            }
            .stat-number {
                font-size: 28px;
            }
            h2 {
                font-size: 22px;
            }
        }

        @media screen and (min-width: 641px) {
            .mobile-bottom-nav {
                display: none;
            }
        }