:root {
    --primary: #2563EB;
    --primary-light: #3B82F6;
    --primary-dark: #1D4ED8;
    --gold: #F59E0B;
    --bg: #F0F7FF;
    --white: #FFFFFF;
    --text: #1E293B;
    --text-secondary: #64748B;
    --border: #E2E8F0;
    --shadow-sm: 0 1px 3px rgba(15, 23, 42, 0.08);
    --shadow: 0 10px 30px rgba(15, 23, 42, 0.08);
    --shadow-lg: 0 24px 70px rgba(15, 23, 42, 0.13);
    --radius: 22px;
    --radius-sm: 14px;
    --transition: all 0.3s ease;
}

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

html {
    scroll-behavior: smooth;
}

body {
    min-width: 320px;
    color: var(--text);
    background: var(--bg);
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Microsoft YaHei", sans-serif;
    line-height: 1.8;
    -webkit-font-smoothing: antialiased;
}

a {
    color: inherit;
}

.container {
    width: min(1200px, calc(100% - 40px));
    margin: 0 auto;
}

.site-header {
    position: sticky;
    top: 0;
    z-index: 50;
    background: rgba(255, 255, 255, 0.94);
    border-bottom: 1px solid var(--border);
    box-shadow: var(--shadow-sm);
    backdrop-filter: blur(18px);
    -webkit-backdrop-filter: blur(18px);
}

.header-inner {
    display: flex;
    align-items: center;
    justify-content: space-between;
    height: 68px;
}

.logo {
    display: inline-flex;
    align-items: center;
    text-decoration: none;
}

.logo img {
    width: 160px;
    height: 44px;
}

.nav {
    display: flex;
    align-items: center;
    gap: 30px;
}

.nav a {
    color: var(--text-secondary);
    text-decoration: none;
    font-size: 15px;
    font-weight: 600;
    transition: var(--transition);
}

.nav a:hover,
.nav a.active {
    color: var(--primary);
}

.menu-btn {
    display: none;
    border: 0;
    background: transparent;
    color: var(--text);
    font-size: 26px;
    cursor: pointer;
}

.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 8px;
    min-height: 48px;
    padding: 12px 28px;
    border-radius: 999px;
    border: 0;
    font-size: 15px;
    font-weight: 700;
    text-decoration: none;
    cursor: pointer;
    transition: var(--transition);
}

.btn-primary {
    color: #fff;
    background: linear-gradient(135deg, var(--primary), var(--primary-light));
    box-shadow: 0 10px 24px rgba(37, 99, 235, 0.26);
}

.btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: 0 16px 34px rgba(37, 99, 235, 0.34);
}

.btn-secondary {
    color: var(--primary);
    background: var(--white);
    border: 2px solid #BFDBFE;
}

.btn-secondary:hover {
    border-color: var(--primary);
    transform: translateY(-2px);
}

.hero {
    position: relative;
    overflow: hidden;
    padding: 86px 0 68px;
    background:
        radial-gradient(circle at 20% 18%, rgba(59, 130, 246, 0.14), transparent 28%),
        linear-gradient(180deg, #EFF6FF 0%, var(--bg) 100%);
}

.hero-grid {
    display: grid;
    grid-template-columns: minmax(0, 1fr) 520px;
    align-items: center;
    gap: 58px;
}

.eyebrow {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    margin-bottom: 18px;
    padding: 7px 14px;
    border: 1px solid #BFDBFE;
    border-radius: 999px;
    color: var(--primary-dark);
    background: rgba(255, 255, 255, 0.75);
    font-size: 13px;
    font-weight: 700;
}

.hero h1 {
    margin-bottom: 18px;
    font-size: clamp(34px, 5vw, 58px);
    line-height: 1.12;
    letter-spacing: -1.2px;
}

.highlight {
    background: linear-gradient(135deg, var(--primary), #6366F1);
    background-clip: text;
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
}

.hero-desc {
    max-width: 650px;
    margin-bottom: 28px;
    color: var(--text-secondary);
    font-size: 18px;
}

.hero-actions {
    display: flex;
    flex-wrap: wrap;
    gap: 14px;
    margin-bottom: 22px;
}

.download-meta {
    display: flex;
    flex-wrap: wrap;
    gap: 14px;
    color: var(--text-secondary);
    font-size: 13px;
}

.download-meta span {
    display: inline-flex;
    align-items: center;
    gap: 6px;
}

.hero-visual {
    position: relative;
}

.hero-visual img {
    width: 100%;
    height: auto;
    display: block;
    filter: drop-shadow(0 26px 60px rgba(37, 99, 235, 0.14));
}

.section {
    padding: 70px 0;
}

.section-white {
    background: var(--white);
}

.section-title {
    max-width: 720px;
    margin: 0 auto 42px;
    text-align: center;
}

.section-title h2 {
    margin-bottom: 10px;
    font-size: clamp(26px, 4vw, 36px);
    line-height: 1.25;
}

.section-title p {
    color: var(--text-secondary);
    font-size: 16px;
}

.download-panel {
    display: grid;
    grid-template-columns: 1.1fr 0.9fr;
    gap: 26px;
}

.download-card,
.info-card,
.feature-card,
.step,
.faq-item {
    border: 1px solid var(--border);
    background: var(--white);
    box-shadow: var(--shadow);
}

.download-card {
    padding: 34px;
    border-radius: var(--radius);
}

.download-card h3 {
    margin-bottom: 10px;
    font-size: 24px;
}

.version {
    display: inline-flex;
    margin-bottom: 20px;
    padding: 5px 12px;
    border-radius: 999px;
    color: #92400E;
    background: #FEF3C7;
    font-size: 13px;
    font-weight: 700;
}

.system-list {
    display: grid;
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 12px;
    margin: 22px 0;
}

.system-option {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 14px 16px;
    border: 1px solid var(--border);
    border-radius: var(--radius-sm);
    color: var(--text-secondary);
    background: #F8FAFC;
    font-size: 14px;
}

.system-option strong {
    color: var(--text);
}

.download-notice {
    margin-top: 18px;
    color: var(--text-secondary);
    font-size: 13px;
}

.info-stack {
    display: grid;
    gap: 16px;
}

.info-card {
    padding: 24px;
    border-radius: var(--radius);
}

.info-card strong {
    display: block;
    margin-bottom: 6px;
    font-size: 18px;
}

.info-card p {
    color: var(--text-secondary);
    font-size: 14px;
}

.feature-grid {
    display: grid;
    grid-template-columns: repeat(3, minmax(0, 1fr));
    gap: 22px;
}

.feature-card {
    padding: 28px;
    border-radius: var(--radius);
    transition: var(--transition);
}

.feature-card:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-lg);
}

.feature-icon {
    display: grid;
    place-items: center;
    width: 54px;
    height: 54px;
    margin-bottom: 15px;
    border-radius: 16px;
    background: linear-gradient(135deg, #EFF6FF, #DBEAFE);
    font-size: 26px;
}

.feature-card h3 {
    margin-bottom: 8px;
    font-size: 18px;
}

.feature-card p {
    color: var(--text-secondary);
    font-size: 14px;
}

.steps {
    display: grid;
    grid-template-columns: repeat(4, minmax(0, 1fr));
    gap: 20px;
}

.step {
    padding: 26px;
    border-radius: var(--radius);
    text-align: center;
}

.step-number {
    display: grid;
    place-items: center;
    width: 52px;
    height: 52px;
    margin: 0 auto 14px;
    border-radius: 999px;
    color: #fff;
    background: linear-gradient(135deg, var(--primary), var(--primary-light));
    font-size: 22px;
    font-weight: 800;
}

.step p {
    color: var(--text-secondary);
    font-size: 14px;
}

.platform-strip {
    padding: 44px 0;
    border-radius: 28px;
    color: #fff;
    background: linear-gradient(135deg, var(--primary), var(--primary-dark));
}

.platform-grid {
    display: grid;
    grid-template-columns: repeat(4, minmax(0, 1fr));
    gap: 18px;
}

.platform {
    padding: 20px;
    border: 1px solid rgba(255, 255, 255, 0.18);
    border-radius: var(--radius-sm);
    background: rgba(255, 255, 255, 0.1);
}

.platform strong {
    display: block;
    margin-bottom: 4px;
    font-size: 18px;
}

.platform span {
    color: #DBEAFE;
    font-size: 13px;
}

.faq-list {
    max-width: 860px;
    margin: 0 auto;
}

.faq-item {
    margin-bottom: 12px;
    padding: 20px 24px;
    border-radius: var(--radius-sm);
    cursor: pointer;
}

.faq-item h3 {
    font-size: 16px;
}

.faq-answer {
    display: none;
    margin-top: 8px;
    color: var(--text-secondary);
    font-size: 14px;
}

.faq-item.open .faq-answer {
    display: block;
}

.site-footer {
    padding: 46px 0 24px;
    color: #CBD5E1;
    background: #1E293B;
}

.footer-grid {
    display: grid;
    grid-template-columns: 1.4fr repeat(3, 1fr);
    gap: 30px;
    margin-bottom: 30px;
}

.site-footer h4 {
    margin-bottom: 12px;
    color: #fff;
    font-size: 15px;
}

.site-footer p,
.site-footer a {
    color: #94A3B8;
    font-size: 13px;
    text-decoration: none;
}

.site-footer a {
    display: block;
    margin-bottom: 8px;
}

.footer-bottom {
    padding-top: 20px;
    border-top: 1px solid #334155;
    text-align: center;
}

@media (max-width: 980px) {
    .hero-grid,
    .download-panel {
        grid-template-columns: 1fr;
    }

    .hero-visual {
        max-width: 620px;
        margin: 0 auto;
    }

    .feature-grid,
    .steps,
    .platform-grid {
        grid-template-columns: repeat(2, minmax(0, 1fr));
    }
}

@media (max-width: 760px) {
    .container {
        width: min(100% - 28px, 1200px);
    }

    .nav {
        display: none;
        position: absolute;
        top: 68px;
        right: 14px;
        left: 14px;
        flex-direction: column;
        align-items: stretch;
        gap: 8px;
        padding: 18px;
        border: 1px solid var(--border);
        border-radius: var(--radius);
        background: #fff;
        box-shadow: var(--shadow-lg);
    }

    .nav.open {
        display: flex;
    }

    .menu-btn {
        display: block;
    }

    .hero {
        padding: 58px 0 44px;
    }

    .hero-actions,
    .download-meta {
        flex-direction: column;
        align-items: stretch;
    }

    .btn {
        width: 100%;
    }

    .system-list,
    .feature-grid,
    .steps,
    .platform-grid,
    .footer-grid {
        grid-template-columns: 1fr;
    }

    .section {
        padding: 48px 0;
    }
}