/* ===== CSS 变量定义 · 暖橙官方基调（与首页统一） ===== */
:root {
    --primary-color: #f59e0b;
    --primary-hover: #d97706;
    --primary-light: #fef3c7;
    --accent-color: #f97316;
    --accent-soft: #ffedd5;
    --trust-blue: #2563eb;
    --trust-blue-light: #eff6ff;
    --text-main: #1e293b;
    --text-muted: #64748b;
    --text-light: #94a3b8;
    --bg-white: #ffffff;
    --bg-warm: #fffbf5;
    --bg-card: #fffdf7;
    --bg-footer: #1e293b;
    --border-color: #fde68a;
    --border-dark: #e2d4b0;
    --border-subtle: #fef9c3;
    --shadow-sm: 0 4px 14px rgba(245, 158, 11, 0.10);
    --shadow-md: 0 12px 24px -10px rgba(245, 158, 11, 0.14);
    --shadow-lg: 0 25px 50px -12px rgba(0, 0, 0, 0.20);
    --radius-md: 12px;
    --radius-lg: 20px;
    --max-width: 1200px;
    --transition-fast: 0.2s ease;
    --transition-smooth: 0.3s ease;
}

/* ===== 全局重置 ===== */
*,
*::before,
*::after {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

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

body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "PingFang SC", "Microsoft YaHei", "Helvetica Neue", Arial, sans-serif;
    color: var(--text-main);
    background-color: var(--bg-white);
    line-height: 1.6;
    overflow-x: hidden;
    font-size: 16px;
    text-rendering: optimizeLegibility;
    -webkit-font-smoothing: antialiased;
}

/* ===== 导航栏（与首页完全相同） ===== */
header {
    position: sticky;
    top: 0;
    background-color: rgba(255, 255, 255, 0.94);
    backdrop-filter: blur(14px);
    -webkit-backdrop-filter: blur(14px);
    border-bottom: 1px solid var(--border-subtle);
    z-index: 1000;
    transition: background-color var(--transition-smooth);
    box-shadow: 0 1px 4px rgba(0, 0, 0, 0.04);
}

.nav-container {
    max-width: var(--max-width);
    margin: 0 auto;
    padding: 0 24px;
    height: 72px;
    display: flex;
    align-items: center;
    justify-content: space-between;
}

.logo-box {
    flex-shrink: 0;
}

.logo-link {
    display: flex;
    align-items: center;
    text-decoration: none;
    color: var(--text-main);
    font-weight: 700;
    font-size: 19px;
    gap: 10px;
    letter-spacing: -0.2px;
}

.logo-img {
    width: 32px;
    height: 32px;
}

.nav-menu {
    display: flex;
    align-items: center;
    gap: 28px;
}

.nav-item {
    text-decoration: none;
    color: var(--text-muted);
    font-weight: 500;
    font-size: 15px;
    transition: color var(--transition-fast);
    position: relative;
    padding: 6px 0;
}

.nav-item::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 0;
    width: 0;
    height: 2px;
    background-color: var(--primary-color);
    transition: width var(--transition-fast);
    border-radius: 2px;
}

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

.nav-item:hover::after,
.nav-item.active::after {
    width: 100%;
}

/* ===== Hero 区域（与首页结构相似，文案调整） ===== */
.hero-section {
    max-width: var(--max-width);
    margin: 0 auto;
    padding: 80px 24px 50px;
    display: flex;
    align-items: center;
    gap: 48px;
    flex-wrap: wrap;
}

.hero-text {
    flex: 1 1 55%;
    min-width: 300px;
}

.hero-badge {
    display: inline-flex;
    align-items: center;
    background-color: var(--primary-light);
    color: var(--primary-hover);
    padding: 7px 18px;
    border-radius: 40px;
    font-size: 13px;
    font-weight: 600;
    margin-bottom: 24px;
    gap: 6px;
    letter-spacing: 0.2px;
}

.hero-text h1 {
    font-size: 42px;
    line-height: 1.2;
    margin-bottom: 18px;
    font-weight: 800;
    letter-spacing: -0.5px;
    color: #1e293b;
}

.hero-text h1 span {
    color: var(--primary-color);
    display: block;
    font-weight: 900;
}

.hero-desc {
    font-size: 16px;
    color: var(--text-muted);
    margin-bottom: 32px;
    max-width: 560px;
    line-height: 1.75;
}

.hero-desc strong {
    color: #1e293b;
    font-weight: 600;
}

.hero-mini-note {
    font-size: 13px;
    color: var(--text-light);
    margin-top: 8px;
}

.hero-actions {
    display: flex;
    flex-wrap: wrap;
    gap: 14px;
    margin-bottom: 16px;
}

.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    text-decoration: none;
    padding: 14px 28px;
    border-radius: 10px;
    font-weight: 600;
    font-size: 15px;
    transition: all var(--transition-fast);
    text-align: center;
    cursor: pointer;
    gap: 6px;
}

.btn-primary {
    background-color: var(--primary-color);
    color: #fff;
    box-shadow: 0 4px 16px rgba(245, 158, 11, 0.30);
    border: 1px solid rgba(255, 255, 255, 0.2);
}

.btn-primary:hover {
    background-color: var(--primary-hover);
    transform: translateY(-2px);
    box-shadow: 0 8px 24px rgba(245, 158, 11, 0.40);
}

.btn-secondary {
    background-color: var(--bg-white);
    color: var(--text-main);
    border: 1px solid #e2e8f0;
}

.btn-secondary:hover {
    background-color: #fefce8;
    border-color: var(--primary-color);
}

.hero-image-cell {
    flex: 1 1 45%;
    min-width: 280px;
    display: flex;
    justify-content: center;
    align-items: center;
    align-self: center;
}

.hero-placeholder-img {
    width: 100%;
    max-width: 460px;
    height: 300px;
    object-fit: cover;
    border-radius: var(--radius-lg);
    border: 1px solid var(--border-subtle);
    background: linear-gradient(135deg, #fef3c7 0%, #fde68a 40%, #f59e0b 100%);
    box-shadow: var(--shadow-md);
}

/* ===== 通用区块标题样式 ===== */
.section-title {
    font-size: 30px;
    font-weight: 800;
    text-align: center;
    margin-bottom: 16px;
    letter-spacing: -0.5px;
    position: relative;
    padding-bottom: 20px;
    color: #1e293b;
}

.section-title::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 50%;
    transform: translateX(-50%);
    width: 48px;
    height: 4px;
    background: linear-gradient(90deg, #f59e0b, #f97316);
    border-radius: 2px;
}

.section-subtitle {
    text-align: center;
    color: var(--text-muted);
    margin-bottom: 50px;
    font-size: 16px;
    max-width: 700px;
    margin-left: auto;
    margin-right: auto;
}

/* ===== 三大下载通道 · 创意版块 ===== */
.channel-intro-section {
    max-width: var(--max-width);
    margin: 60px auto;
    padding: 0 24px;
}

.channel-cards {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 28px;
    margin-top: 40px;
}

.channel-card {
    background: #fffdf7;
    border: 1px solid #fef3c7;
    border-radius: var(--radius-lg);
    padding: 34px 28px;
    text-align: center;
    transition: all var(--transition-smooth);
    position: relative;
    box-shadow: 0 2px 8px rgba(0, 0, 0, 0.02);
}

.channel-card:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-md);
    border-color: var(--primary-color);
}

.channel-icon {
    font-size: 40px;
    margin-bottom: 18px;
}

.channel-card h3 {
    font-size: 20px;
    font-weight: 700;
    margin-bottom: 14px;
    color: #1e293b;
}

.channel-card p {
    font-size: 14px;
    color: var(--text-muted);
    line-height: 1.65;
    margin-bottom: 20px;
}

.channel-badge {
    display: inline-block;
    padding: 4px 14px;
    border-radius: 16px;
    font-size: 12px;
    font-weight: 700;
    letter-spacing: 0.3px;
}

.channel-badge.primary {
    background-color: #fef3c7;
    color: #b45309;
}

.channel-badge.secondary {
    background-color: #dbeafe;
    color: #1e40af;
}

.channel-badge.tertiary {
    background-color: #f1f5f9;
    color: #475569;
}

/* ===== 下载矩阵 ===== */
.download-matrix-section {
    max-width: var(--max-width);
    margin: 80px auto;
    padding: 0 24px;
}

.download-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(320px, 1fr));
    gap: 28px;
    margin-top: 40px;
}

.download-card {
    background: var(--bg-white);
    border: 1px solid #fef3c7;
    border-radius: var(--radius-lg);
    padding: 28px 24px;
    transition: all var(--transition-smooth);
    box-shadow: 0 2px 8px rgba(0, 0, 0, 0.02);
    display: flex;
    flex-direction: column;
}

.download-card:hover {
    box-shadow: var(--shadow-md);
    border-color: var(--primary-color);
    transform: translateY(-2px);
}

.download-card-header {
    display: flex;
    align-items: center;
    gap: 14px;
    margin-bottom: 16px;
}

.os-icon {
    font-size: 32px;
    flex-shrink: 0;
}

.os-info h3 {
    font-size: 19px;
    font-weight: 700;
    color: #1e293b;
    margin-bottom: 4px;
}

.os-version {
    font-size: 13px;
    color: var(--text-muted);
}

.download-card-body {
    flex: 1;
    display: flex;
    flex-direction: column;
    gap: 16px;
}

.os-desc {
    font-size: 14px;
    color: #475569;
    line-height: 1.6;
}

.download-options {
    display: flex;
    flex-wrap: wrap;
    gap: 10px;
}

.btn-download {
    background-color: var(--primary-color);
    color: #fff;
    padding: 10px 20px;
    border-radius: 8px;
    font-size: 14px;
    font-weight: 600;
    text-decoration: none;
    display: inline-flex;
    align-items: center;
    gap: 6px;
    transition: all var(--transition-fast);
    border: none;
    cursor: pointer;
}

.btn-download:hover {
    background-color: var(--primary-hover);
    transform: translateY(-1px);
    box-shadow: 0 4px 12px rgba(245, 158, 11, 0.35);
}

.btn-download-outline {
    background-color: #fff;
    color: var(--primary-hover);
    border: 1px solid var(--primary-color);
    padding: 10px 20px;
    border-radius: 8px;
    font-size: 14px;
    font-weight: 600;
    text-decoration: none;
    display: inline-flex;
    align-items: center;
    gap: 6px;
    transition: all var(--transition-fast);
}

.btn-download-outline:hover {
    background-color: #fefce8;
    border-color: var(--primary-hover);
}

.checksum-row {
    font-size: 12px;
    color: var(--text-muted);
    background-color: #f8fafc;
    padding: 10px 14px;
    border-radius: 8px;
    display: flex;
    align-items: center;
    gap: 8px;
    flex-wrap: wrap;
    border: 1px solid #f1f5f9;
    margin-top: auto;
}

.checksum-label {
    font-weight: 600;
    color: #334155;
}

.checksum-row code {
    font-family: 'SF Mono', 'Menlo', monospace;
    background-color: #fff;
    padding: 2px 8px;
    border-radius: 4px;
    font-size: 11px;
    word-break: break-all;
}

.download-note-box {
    background-color: #fffbeb;
    border: 1px solid #fde68a;
    border-radius: 14px;
    padding: 20px 24px;
    margin-top: 36px;
    display: flex;
    align-items: flex-start;
    gap: 14px;
    box-shadow: 0 1px 3px rgba(0, 0, 0, 0.02);
}

.note-icon {
    font-size: 24px;
    flex-shrink: 0;
}

.download-note-box p {
    font-size: 14px;
    color: #92400e;
    line-height: 1.65;
    margin: 0;
}

/* ===== 安装教程步骤 ===== */
.install-guide-section {
    max-width: var(--max-width);
    margin: 80px auto;
    padding: 0 24px;
}

.steps-container {
    max-width: 800px;
    margin: 40px auto 0;
    display: flex;
    flex-direction: column;
    gap: 28px;
}

.step-item {
    display: flex;
    gap: 20px;
    background: #fffdf7;
    border: 1px solid #fef3c7;
    border-radius: 16px;
    padding: 28px 24px;
    transition: all var(--transition-smooth);
    box-shadow: 0 1px 3px rgba(0, 0, 0, 0.02);
}

.step-item:hover {
    border-color: var(--primary-color);
    box-shadow: var(--shadow-sm);
}

.step-number {
    font-size: 36px;
    font-weight: 800;
    color: #f59e0b;
    line-height: 1;
    flex-shrink: 0;
    width: 48px;
    text-align: center;
    opacity: 0.8;
}

.step-content h3 {
    font-size: 19px;
    font-weight: 700;
    color: #1e293b;
    margin-bottom: 10px;
}

.step-content p {
    font-size: 14px;
    color: #475569;
    line-height: 1.7;
    margin-bottom: 12px;
}

.step-tip {
    font-size: 13px;
    background-color: #fefce8;
    padding: 10px 16px;
    border-radius: 10px;
    color: #92400e;
    line-height: 1.5;
    border-left: 3px solid #f59e0b;
}

.step-tip code {
    background: #fff;
    padding: 1px 6px;
    border-radius: 3px;
    font-family: monospace;
    font-size: 12px;
}

.install-video-teaser {
    max-width: 800px;
    margin: 40px auto 0;
    background: linear-gradient(135deg, #fefce8, #fffbeb);
    border: 1px solid #fde68a;
    border-radius: 16px;
    padding: 28px 24px;
    text-align: center;
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 14px;
}

.teaser-icon {
    font-size: 36px;
}

.install-video-teaser p {
    font-size: 15px;
    color: #475569;
    line-height: 1.6;
}

/* ===== 下载前须知 · 创意版块 ===== */
.before-download-section {
    max-width: var(--max-width);
    margin: 80px auto 100px;
    padding: 0 24px;
}

.notice-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
    gap: 24px;
    margin-top: 40px;
}

.notice-card {
    background: #fff;
    border-radius: 14px;
    padding: 28px 24px;
    border: 1px solid #f1f5f9;
    transition: all var(--transition-smooth);
    box-shadow: 0 1px 3px rgba(0, 0, 0, 0.02);
}

.notice-card:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-sm);
}

.notice-card.warning {
    border-left: 4px solid #f97316;
}

.notice-card.info {
    border-left: 4px solid #f59e0b;
}

.notice-icon {
    font-size: 30px;
    margin-bottom: 14px;
}

.notice-card h3 {
    font-size: 17px;
    font-weight: 700;
    color: #1e293b;
    margin-bottom: 10px;
}

.notice-card p {
    font-size: 14px;
    color: #475569;
    line-height: 1.65;
}

/* ===== 页脚（与首页完全相同） ===== */
footer {
    background-color: #1e293b;
    color: #94a3b8;
    padding: 64px 0 28px;
    font-size: 14px;
    border-top: 1px solid #334155;
}

.footer-container {
    max-width: var(--max-width);
    margin: 0 auto;
    padding: 0 24px;
    display: flex;
    flex-wrap: wrap;
    gap: 40px;
}

.footer-info {
    flex: 1 1 300px;
}

.footer-info h4 {
    color: #fff;
    font-size: 17px;
    margin-bottom: 16px;
    font-weight: 700;
}

.footer-info p {
    margin-bottom: 10px;
    line-height: 1.6;
}

.footer-links {
    flex: 2 1 500px;
}

.footer-links-table {
    display: flex;
    flex-wrap: wrap;
    gap: 36px;
}

.footer-col {
    flex: 1 1 140px;
}

.footer-col h5 {
    color: #fff;
    font-size: 14px;
    margin-bottom: 16px;
    font-weight: 600;
    letter-spacing: 0.4px;
}

.footer-col ul {
    list-style: none;
}

.footer-col li {
    margin-bottom: 10px;
}

.footer-col a {
    color: #94a3b8;
    text-decoration: none;
    transition: color var(--transition-fast);
}

.footer-col a:hover {
    color: #f59e0b;
}

.footer-bottom {
    max-width: var(--max-width);
    margin: 44px auto 0;
    padding: 22px 24px 0;
    border-top: 1px solid #334155;
    text-align: center;
    font-size: 12px;
    color: #64748b;
    line-height: 1.6;
}

/* ===== 响应式设计 ===== */
@media (max-width: 768px) {
    .nav-container {
        flex-direction: column;
        height: auto;
        padding: 14px 20px;
        align-items: flex-start;
    }

    .nav-menu {
        flex-wrap: wrap;
        gap: 14px;
        margin-top: 10px;
    }

    .hero-section {
        flex-direction: column;
        padding: 44px 18px 36px;
        gap: 28px;
    }

    .hero-text h1 {
        font-size: 30px;
    }

    .hero-placeholder-img {
        height: 200px;
    }

    .section-title {
        font-size: 24px;
    }

    .download-grid,
    .channel-cards,
    .notice-grid {
        grid-template-columns: 1fr;
    }

    .step-item {
        flex-direction: column;
        gap: 12px;
    }

    .step-number {
        width: auto;
        text-align: left;
    }

    .footer-container {
        flex-direction: column;
    }

    .footer-links-table {
        flex-direction: column;
        gap: 26px;
    }
}

@media (max-width: 480px) {
    .hero-text h1 {
        font-size: 25px;
    }

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

    .btn {
        width: 100%;
        text-align: center;
    }

    .download-options {
        flex-direction: column;
    }

    .btn-download,
    .btn-download-outline {
        width: 100%;
        justify-content: center;
    }
}