/* =========================================================
   全局变量（默认亮色模式）
   ========================================================= */
:root {
    --bg-color: #f8fafc;
    --header-bg: #ffffff;
    --card-bg: #ffffff;
    --card-sub-bg: #f8fafc;
    --text-main: #0f172a;
    --text-sub: #475569;
    --text-muted: #64748b;
    --border-color: #e2e8f0;
    --primary-color: #2563eb;
    --primary-hover: #1d4ed8;
    --card-shadow: 0 10px 30px rgba(0, 0, 0, 0.08);
    --hero-bg: linear-gradient(135deg, #0f172a 0%, #1e3a8a 100%);
    --check-color: #16a34a;
}

/* =========================================================
   黑夜模式变量（通过 JS 自动赋予 dark-mode 类）
   ========================================================= */
body.dark-mode {
    --bg-color: #0b0f19;
    --header-bg: #111827;
    --card-bg: #1e293b;
    --card-sub-bg: #111827;
    --text-main: #f8fafc;
    --text-sub: #cbd5e1;
    --text-muted: #94a3b8;
    --border-color: #334155;
    --primary-color: #3b82f6;
    --primary-hover: #2563eb;
    --card-shadow: 0 10px 30px rgba(0, 0, 0, 0.5);
    --hero-bg: linear-gradient(135deg, #030712 0%, #1e1b4b 100%);
    --check-color: #22c55e;
}

/* 重置基础样式 */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
}

body {
    background-color: var(--bg-color);
    color: var(--text-sub);
    line-height: 1.6;
    transition: background-color 0.3s ease, color 0.3s ease;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
}

/* 通用按钮 */
.btn {
    display: inline-block;
    padding: 9px 22px;
    border-radius: 8px;
    text-decoration: none;
    font-size: 15px;
    font-weight: 500;
    transition: all 0.3s ease;
    cursor: pointer;
    border: none;
}

.btn-primary {
    background-color: var(--primary-color);
    color: #ffffff;
}

.btn-primary:hover {
    background-color: var(--primary-hover);
}

/* 导航栏 */
.header {
    background-color: var(--header-bg);
    box-shadow: 0 2px 10px rgba(0, 0, 0, 0.05);
    position: sticky;
    top: 0;
    z-index: 1000;
    transition: background-color 0.3s ease;
}

.navbar {
    display: flex;
    align-items: center;
    justify-content: space-between;
    height: 70px;
}

.logo a {
    display: flex;
    align-items: center;
    gap: 12px;
    text-decoration: none;
}

.logo img {
    height: 40px;
    object-fit: contain;
}

.logo-text {
    font-size: 20px;
    font-weight: 700;
    color: var(--text-main);
    letter-spacing: -0.5px;
}

.nav-menu ul {
    display: flex;
    list-style: none;
    gap: 32px;
}

.nav-menu a {
    text-decoration: none;
    color: var(--text-sub);
    font-weight: 500;
    font-size: 15px;
    transition: color 0.2s;
}

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

.nav-toggle {
    display: none;
    background: transparent;
    border: none;
    flex-direction: column;
    gap: 5px;
    cursor: pointer;
}

.nav-toggle span {
    width: 24px;
    height: 2px;
    background-color: var(--text-main);
    transition: all 0.3s;
}

/* Hero 头部视觉区 */
.hero {
    background: var(--hero-bg);
    color: #ffffff;
    padding: 80px 0 100px;
    text-align: center;
}

.hero-content h1 {
    font-size: 40px;
    font-weight: 700;
    margin-bottom: 20px;
    letter-spacing: -0.5px;
}

.hero-content p {
    font-size: 18px;
    color: #94a3b8;
    max-width: 720px;
    margin: 0 auto;
}

/* 产品展示区域（圆角卡片，左文右图） */
.showcase {
    margin-top: -60px;
    padding-bottom: 70px;
}

.showcase-card {
    background: var(--card-bg);
    border: 1px solid var(--border-color);
    border-radius: 20px;
    box-shadow: var(--card-shadow);
    padding: 40px;
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 40px;
    transition: background-color 0.3s, border-color 0.3s, box-shadow 0.3s;
}

.showcase-left {
    flex: 1.2;
}

.showcase-main-title {
    font-size: 32px;
    font-weight: 800;
    color: var(--text-main);
    margin-bottom: 24px;
}

.feature-group {
    margin-bottom: 20px;
}

.feature-group:last-child {
    margin-bottom: 0;
}

.feature-group-title {
    font-size: 18px;
    font-weight: 600;
    color: var(--text-main);
    margin-bottom: 10px;
}

.check-list {
    list-style: none;
    display: flex;
    flex-wrap: wrap;
    gap: 10px 24px;
}

.check-list li {
    font-size: 14px;
    color: var(--text-sub);
    display: flex;
    align-items: center;
}

.check-icon {
    color: var(--check-color);
    font-weight: bold;
    margin-right: 6px;
}

.showcase-right {
    flex: 1;
    display: flex;
    justify-content: center;
    align-items: center;
}

.showcase-right img {
    width: 100%;
    max-width: 480px;
    height: auto;
    border-radius: 12px;
    object-fit: cover;
}

/* 通用标题 */
.section-title {
    text-align: center;
    margin-bottom: 48px;
}

.section-title h2 {
    font-size: 30px;
    color: var(--text-main);
    margin-bottom: 10px;
}

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

/* 下载区域 */
.download-section {
    padding: 70px 0;
    background-color: var(--card-bg);
    transition: background-color 0.3s;
}

.download-grid {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 24px;
}

.download-card {
    background: var(--card-sub-bg);
    border: 1px solid var(--border-color);
    border-radius: 14px;
    padding: 32px 20px;
    text-align: center;
    text-decoration: none;
    color: inherit;
    transition: transform 0.3s, box-shadow 0.3s, border-color 0.3s;
    display: flex;
    flex-direction: column;
    align-items: center;
}

.download-card:hover {
    transform: translateY(-6px);
    box-shadow: var(--card-shadow);
    border-color: var(--primary-color);
}

.download-icon {
    font-size: 38px;
    margin-bottom: 16px;
}

.download-card h3 {
    font-size: 18px;
    color: var(--text-main);
    margin-bottom: 8px;
}

.download-card p {
    font-size: 13px;
    color: var(--text-muted);
    margin-bottom: 20px;
    flex-grow: 1;
}

.btn-download {
    display: inline-block;
    padding: 8px 20px;
    background-color: var(--primary-color);
    color: #ffffff;
    border-radius: 6px;
    font-size: 14px;
    font-weight: 500;
    transition: background-color 0.2s;
    width: 100%;
}

.btn-h5 {
    background-color: #0284c7;
}

.download-card:hover .btn-download {
    background-color: var(--primary-hover);
}

/* 产品优势卡片 */
.features-section {
    padding: 80px 0;
}

.feature-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 28px;
}

.feature-card {
    background: var(--card-bg);
    padding: 32px 24px;
    border-radius: 14px;
    border: 1px solid var(--border-color);
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.03);
    transition: transform 0.3s, box-shadow 0.3s, background-color 0.3s, border-color 0.3s;
}

.feature-card:hover {
    transform: translateY(-5px);
    box-shadow: var(--card-shadow);
}

.card-icon {
    width: 48px;
    height: 48px;
    background-color: var(--card-sub-bg);
    border-radius: 10px;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 22px;
    margin-bottom: 20px;
}

.feature-card h3 {
    font-size: 18px;
    color: var(--text-main);
    margin-bottom: 10px;
}

.feature-card p {
    font-size: 14px;
    color: var(--text-muted);
    line-height: 1.6;
}

/* 联系我们区域 */
.contact-section {
    padding: 80px 0;
    background-color: var(--card-bg);
    transition: background-color 0.3s;
}

.contact-grid {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 32px;
}

.contact-card {
    background: var(--card-sub-bg);
    border: 1px solid var(--border-color);
    border-radius: 16px;
    padding: 36px;
    box-shadow: 0 4px 15px rgba(0, 0, 0, 0.02);
    transition: background-color 0.3s, border-color 0.3s;
}

.contact-header {
    display: flex;
    align-items: center;
    gap: 12px;
    margin-bottom: 24px;
}

.contact-icon {
    width: 44px;
    height: 44px;
    background: var(--primary-color);
    color: #ffffff;
    border-radius: 10px;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 20px;
}

.contact-header h3 {
    font-size: 20px;
    color: var(--text-main);
}

.contact-list {
    list-style: none;
}

.contact-list li {
    padding: 10px 0;
    border-bottom: 1px dashed var(--border-color);
    color: var(--text-sub);
    font-size: 15px;
}

.contact-list li:last-child {
    border-bottom: none;
}

.contact-list strong {
    color: var(--text-main);
}

/* 页脚 */
.footer {
    background-color: #0f172a;
    color: #94a3b8;
    padding: 30px 0;
    text-align: center;
    font-size: 14px;
}

/* 移动端响应式适配 */
@media (max-width: 992px) {
    .download-grid {
        grid-template-columns: repeat(2, 1fr);
    }

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

@media (max-width: 768px) {
    .nav-toggle {
        display: flex;
    }

    .nav-menu {
        display: none;
        position: absolute;
        top: 70px;
        left: 0;
        width: 100%;
        background: var(--header-bg);
        box-shadow: 0 10px 15px rgba(0, 0, 0, 0.1);
        padding: 20px 0;
    }

    .nav-menu.active {
        display: block;
    }

    .nav-menu ul {
        flex-direction: column;
        align-items: center;
        gap: 20px;
    }

    .hero-content h1 {
        font-size: 28px;
    }

    .hero-content p {
        font-size: 15px;
    }

    /* 移动端卡片布局改为上下颠倒（图片在上，文字在下）或顺排 */
    .showcase-card {
        flex-direction: column-reverse;
        padding: 24px;
        gap: 24px;
    }

    .showcase-main-title {
        font-size: 24px;
        margin-bottom: 20px;
    }

    .check-list {
        flex-direction: column;
        gap: 8px;
    }

    .download-grid {
        grid-template-columns: 1fr;
    }

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

    .contact-grid {
        grid-template-columns: 1fr;
    }

    .contact-card {
        padding: 24px;
    }
}