:root {
            color-scheme: light;
            --ink: #172033;
            --muted: #5c6b7d;
            --line: #d9e2ec;
            --panel: #ffffff;
            --blue: #1d4ed8;
            --green: #047857;
            --red: #b91c1c;
            --gold: #9a6a14;
            --soft: #f7f9fc;
        }

        * {
            box-sizing: border-box;
        }

        body {
            margin: 0;
            font-family: Inter, "Segoe UI", "Microsoft YaHei", Arial, sans-serif;
            color: var(--ink);
            background: var(--soft);
        }

        a {
            color: inherit;
            text-decoration: none;
        }

        .site-header {
            position: fixed;
            top: 0;
            left: 0;
            right: 0;
            z-index: 20;
            display: flex;
            align-items: center;
            justify-content: space-between;
            gap: 24px;
            padding: 16px clamp(18px, 4vw, 56px);
            background: rgba(255, 255, 255, 0.94);
            border-bottom: 1px solid rgba(217, 226, 236, 0.9);
            backdrop-filter: blur(12px);
        }

        .brand {
            display: inline-flex;
            align-items: center;
            gap: 12px;
            font-weight: 800;
            letter-spacing: 0;
        }

        .brand img {
            width: 72px;
            height: 72px;
            object-fit: contain;
        }

        .nav-actions {
            display: flex;
            align-items: center;
            gap: 12px;
            flex-wrap: wrap;
            justify-content: flex-end;
        }

        .nav-link {
            min-height: 40px;
            display: inline-flex;
            align-items: center;
            justify-content: center;
            padding: 8px 16px;
            border: 1px solid rgba(23, 32, 51, 0.18);
            border-radius: 8px;
            background: #ffffff;
            font-weight: 700;
            color: var(--ink);
            transition: border-color 0.16s ease, background 0.16s ease, color 0.16s ease;
        }

        .nav-link:hover {
            border-color: rgba(29, 78, 216, 0.42);
            color: var(--blue);
        }

        .nav-link.is-primary {
            border-color: var(--blue);
            background: var(--blue);
            color: #ffffff;
        }

        .nav-user-state {
            color: var(--muted);
            font-weight: 700;
        }

        .is-hidden {
            display: none !important;
        }

        .hero {
            min-height: 82svh;
            position: relative;
            display: flex;
            align-items: center;
            padding: 118px clamp(22px, 6vw, 88px) 72px;
            overflow: hidden;
            color: #ffffff;
            background: #172033 url("../picture/html/efemModel.jpeg") center left / cover no-repeat;
        }

        .hero::before {
            content: "";
            position: absolute;
            inset: 0;
            background: linear-gradient(90deg, rgba(10, 19, 34, 0.88) 0%, rgba(10, 19, 34, 0.64) 50%, rgba(10, 19, 34, 0.26) 100%);
        }

        .hero-content {
            position: relative;
            width: min(680px, 100%);
        }

        .eyebrow {
            margin: 0 0 14px;
            color: #d7e5f6;
            font-weight: 800;
            letter-spacing: 0;
        }

        h1 {
            margin: 0;
            font-size: clamp(40px, 6.8vw, 76px);
            line-height: 1.02;
            letter-spacing: 0;
        }

        .hero-copy {
            max-width: 590px;
            margin: 22px 0 0;
            font-size: clamp(17px, 2vw, 22px);
            line-height: 1.7;
            color: #edf4ff;
        }

        .hero-actions {
            display: flex;
            gap: 14px;
            flex-wrap: wrap;
            margin-top: 34px;
        }

        .hero-button {
            min-height: 48px;
            display: inline-flex;
            align-items: center;
            justify-content: center;
            padding: 12px 22px;
            border-radius: 8px;
            border: 1px solid rgba(255, 255, 255, 0.5);
            font-weight: 800;
            background: rgba(255, 255, 255, 0.12);
            color: #ffffff;
            transition: transform 0.16s ease, background 0.16s ease, border-color 0.16s ease;
        }

        .hero-button:hover {
            transform: translateY(-1px);
            background: rgba(255, 255, 255, 0.18);
        }

        .hero-button.is-primary {
            border-color: #ffffff;
            background: #ffffff;
            color: var(--ink);
        }

        .section {
            padding: 48px clamp(18px, 5vw, 72px);
        }

        .section-inner {
            width: min(1180px, 100%);
            margin: 0 auto;
        }

        .section-title {
            margin: 0 0 22px;
            font-size: clamp(26px, 4vw, 42px);
            line-height: 1.15;
            letter-spacing: 0;
        }

        .feature-grid {
            display: grid;
            grid-template-columns: repeat(3, minmax(0, 1fr));
            gap: 18px;
        }

        .feature-card {
            min-height: 178px;
            padding: 22px;
            border: 1px solid var(--line);
            border-radius: 8px;
            background: var(--panel);
            box-shadow: 0 8px 22px rgba(23, 32, 51, 0.04);
        }

        .feature-kicker {
            margin: 0 0 12px;
            color: var(--blue);
            font-weight: 800;
        }

        .feature-card:nth-child(2) .feature-kicker {
            color: var(--green);
        }

        .feature-card:nth-child(3) .feature-kicker {
            color: var(--red);
        }

        .feature-card h2 {
            margin: 0 0 10px;
            font-size: 21px;
            letter-spacing: 0;
        }

        .feature-card p {
            margin: 0;
            color: var(--muted);
            line-height: 1.75;
        }

        .workflow {
            background: #ffffff;
            border-top: 1px solid var(--line);
            border-bottom: 1px solid var(--line);
        }

        .workflow-list {
            display: grid;
            grid-template-columns: repeat(4, minmax(0, 1fr));
            gap: 14px;
            margin: 0;
            padding: 0;
            list-style: none;
        }

        .workflow-list li {
            min-height: 132px;
            padding: 18px;
            border-left: 3px solid var(--gold);
            background: #f7f9fc;
            border-radius: 8px;
            color: var(--muted);
            line-height: 1.65;
        }

        .workflow-list strong {
            display: block;
            margin-bottom: 8px;
            color: var(--ink);
            font-size: 17px;
        }

        .footer {
            display: flex;
            align-items: center;
            justify-content: space-between;
            gap: 18px;
            padding: 26px clamp(18px, 5vw, 72px);
            color: var(--muted);
            background: var(--soft);
        }

        .footer a {
            color: var(--blue);
            font-weight: 700;
        }

        @media (max-width: 900px) {
            .site-header {
                position: sticky;
                padding: 12px 16px;
            }

            .brand img {
                width: 63px;
                height: 63px;
            }

            .hero {
                min-height: 84svh;
                padding: 56px 22px 42px;
                background-position: center;
            }

            .hero::before {
                background: rgba(11, 18, 32, 0.72);
            }

            .feature-grid,
            .workflow-list {
                grid-template-columns: 1fr;
            }

            .footer {
                align-items: flex-start;
                flex-direction: column;
            }
        }

        @media (max-width: 560px) {
            .site-header {
                align-items: flex-start;
                flex-direction: column;
            }

            .nav-actions {
                width: 100%;
                justify-content: stretch;
            }

            .nav-link {
                flex: 1;
            }

            .hero-actions {
                flex-direction: column;
            }

            .hero-button {
                width: 100%;
            }
        }