/* ========== 全局变量与重置 ========== */
:root {
    --primary-red: #ef443b;
    --primary-dark: #d93833;
    --text-main: #1f2937;
    --text-secondary: #4b5563;
    --bg-light: #f9fafb;
    --border-light: #f0f0f0;
    --shadow-sm: 0 10px 25px rgba(0, 0, 0, 0.02);
    --shadow-md: 0 15px 35px rgba(239, 68, 68, 0.08);
    --shadow-lg: 0 25px 50px rgba(0, 0, 0, 0.05);
    --radius-sm: 8px;
    --radius-md: 16px;
    --radius-lg: 24px;
    --radius-xl: 20px;
}

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

body {
    font-family: 'Noto Sans', 'Noto Sans SC', 'PingFang SC', 'Microsoft YaHei', sans-serif;
    color: var(--text-main);
    background: #ffffff;
    line-height: 1.6;
    overflow-x: hidden;
    -webkit-font-smoothing: antialiased;
}

/* ========== 导航栏 (与首页统一) ========== */
nav {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 0 8%;
    height: 80px;
    position: fixed;
    width: 100%;
    top: 0;
    z-index: 1000;
    background: rgba(255, 255, 255, 0.85);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    border-bottom: 1px solid #f3f4f6;
    transition: background 0.3s ease;
}

.nav-left {
    display: flex;
    align-items: center;
    gap: 40px;
}

.logo img {
    height: 30px;
    width: 158px;
    display: block;
}

.nav-links {
    display: flex;
    list-style: none;
    gap: 8px;
}

.nav-links li {
    display: flex;
    align-items: center;
    gap: 4px;
    padding: 8px 12px;
    border-radius: 6px;
    transition: background 0.2s;
    border-bottom: 3px solid transparent;
}

.nav-links li:hover {
    background: rgba(239, 68, 68, 0.04);
    border-bottom-color: #FFD5D6;
}

.nav-links a {
    text-decoration: none;
    color: var(--text-main);
    font-size: 15px;
    font-weight: 500;
    display: flex;
    align-items: center;
    white-space: nowrap;
}

.nav-links-svg {
    width: 12px;
    height: 12px;
    opacity: 0.7;
}

.nav-right {
    display: flex;
    align-items: center;
    gap: 12px;
}

.btn-link {
    text-decoration: none;
    color: var(--primary-red);
    padding: 10px 24px;
    border: 2px solid var(--primary-red);
    border-radius: var(--radius-sm);
    font-weight: 600;
    font-size: 14px;
    transition: all 0.3s ease;
    white-space: nowrap;
}

.btn-link:hover {
    background: var(--primary-red);
    color: #fff;
}

.btn-outline {
    text-decoration: none;
    color: #fff;
    background: var(--primary-red);
    padding: 11px 24px;
    border-radius: var(--radius-sm);
    font-weight: 600;
    font-size: 14px;
    transition: all 0.3s ease;
    white-space: nowrap;
}

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

/* ========== 下载英雄区 ========== */
.dl-hero {
    padding: 160px 8% 80px;
    background: radial-gradient(circle at 90% 10%, rgba(239, 68, 68, 0.05) 0%, rgba(255, 255, 255, 1) 60%);
    text-align: center;
}

.dl-hero-content {
    max-width: 900px;
    margin: 0 auto;
}

.dl-hero h1 {
    font-size: 3.8rem;
    font-weight: 700;
    margin-bottom: 20px;
    color: var(--text-main);
}

.dl-hero h1 span {
    background: linear-gradient(135deg, #ef443b, #EE8D3B);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.dl-hero-desc {
    font-size: 1.2rem;
    max-width: 700px;
    margin: 0 auto 45px;
    color: var(--text-secondary);
    line-height: 1.8;
}

.main-dl-card {
    background: #fff;
    border-radius: var(--radius-lg);
    padding: 50px 60px;
    box-shadow: 0 25px 50px -12px rgba(0, 0, 0, 0.08);
    display: flex;
    align-items: center;
    gap: 50px;
    border: 1px solid #f3f4f6;
    margin-bottom: 25px;
    text-align: left;
}

.os-info {
    flex: 1;
}

.os-badge {
    display: flex;
    align-items: center;
    gap: 10px;
    color: var(--primary-red);
    font-weight: 700;
    margin-bottom: 12px;
    font-size: 1rem;
}

.os-badge img {
    width: 32px;
    height: 32px;
}

.os-info h3 {
    font-size: 1.8rem;
    font-weight: 700;
    margin-bottom: 8px;
    color: var(--text-main);
}

.os-info p {
    color: var(--text-secondary);
    font-size: 1rem;
    margin-bottom: 10px;
}

.os-extra {
    font-size: 0.85rem;
    color: #9ca3af;
    margin-top: 8px;
}

.btn-dl-large {
    background: var(--primary-red);
    color: #fff;
    padding: 18px 45px;
    border-radius: 12px;
    text-decoration: none;
    font-weight: 700;
    font-size: 1.2rem;
    box-shadow: 0 10px 30px rgba(239, 68, 68, 0.3);
    transition: all 0.3s ease;
    white-space: nowrap;
    display: inline-block;
    text-align: center;
}

.btn-dl-large:hover {
    transform: translateY(-3px);
    box-shadow: 0 15px 35px rgba(239, 68, 68, 0.4);
    background: var(--primary-dark);
}

.dl-alt-links {
    margin-top: 15px;
    font-size: 0.95rem;
    color: #6b7280;
}

.dl-alt-links span {
    font-weight: 500;
}

.dl-alt-links a {
    color: var(--primary-red);
    text-decoration: none;
    font-weight: 500;
    margin: 0 4px;
}

.dl-alt-links a:hover {
    text-decoration: underline;
}

/* ========== 四大优势创意版块 ========== */
.advantage-section {
    padding: 90px 8%;
    background: #fff;
    text-align: center;
}

.advantage-section h2 {
    font-size: 2.8rem;
    font-weight: 700;
    margin-bottom: 15px;
}

.advantage-section h2 span {
    color: var(--primary-red);
}

.section-subtitle {
    max-width: 700px;
    margin: 0 auto 55px;
    color: var(--text-secondary);
    font-size: 1.1rem;
    line-height: 1.7;
}

.advantage-grid {
    display: flex;
    gap: 25px;
    justify-content: center;
    flex-wrap: wrap;
}

.advantage-card {
    background: #f9fafb;
    padding: 35px 25px;
    border-radius: var(--radius-xl);
    flex: 1 1 220px;
    max-width: 270px;
    text-align: left;
    transition: all 0.3s ease;
    border: 1px solid transparent;
}

.advantage-card:hover {
    background: #fff;
    box-shadow: var(--shadow-md);
    border-color: #fecaca;
    transform: translateY(-5px);
}

.advantage-icon {
    font-size: 2.2rem;
    margin-bottom: 18px;
}

.advantage-card h4 {
    font-size: 1.3rem;
    font-weight: 700;
    margin-bottom: 12px;
    color: var(--text-main);
}

.advantage-card p {
    color: var(--text-secondary);
    font-size: 0.95rem;
    line-height: 1.7;
}

/* ========== 安装指引创意版块 ========== */
.install-guide {
    padding: 90px 8%;
    background: var(--bg-light);
    text-align: center;
}

.install-guide h2 {
    font-size: 2.8rem;
    font-weight: 700;
    margin-bottom: 15px;
}

.install-guide h2 span {
    color: var(--primary-red);
}

.steps-grid {
    display: flex;
    gap: 30px;
    justify-content: center;
    flex-wrap: wrap;
    margin-top: 50px;
}

.step-card {
    background: #fff;
    padding: 40px 25px;
    border-radius: var(--radius-xl);
    flex: 1 1 250px;
    max-width: 320px;
    text-align: center;
    box-shadow: var(--shadow-sm);
    transition: all 0.3s ease;
    border: 1px solid #f0f0f0;
    position: relative;
}

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

.step-number {
    position: absolute;
    top: -18px;
    left: 50%;
    transform: translateX(-50%);
    background: var(--primary-red);
    color: #fff;
    width: 36px;
    height: 36px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-weight: 800;
    font-size: 1.1rem;
}

.step-icon {
    margin: 25px 0 20px;
}

.step-icon svg {
    width: 52px;
    height: 52px;
}

.step-card h3 {
    font-size: 1.4rem;
    font-weight: 700;
    margin-bottom: 12px;
}

.step-card p {
    color: var(--text-secondary);
    font-size: 0.95rem;
    line-height: 1.7;
}

.step-card code {
    background: #f3f4f6;
    padding: 2px 8px;
    border-radius: 4px;
    font-family: monospace;
    color: var(--primary-red);
    font-weight: 500;
}

.install-footnote {
    margin-top: 45px;
    font-size: 1rem;
    color: #6b7280;
    background: #fff;
    display: inline-block;
    padding: 12px 25px;
    border-radius: 30px;
    border: 1px solid #eee;
}

/* ========== 版本对比创意版块 ========== */
.version-compare {
    padding: 90px 8%;
    background: #fff;
    text-align: center;
}

.version-compare h2 {
    font-size: 2.8rem;
    font-weight: 700;
    margin-bottom: 15px;
}

.version-compare h2 span {
    color: var(--primary-red);
}

.version-cards {
    display: flex;
    gap: 30px;
    justify-content: center;
    flex-wrap: wrap;
    margin-top: 50px;
}

.version-card {
    background: #fff;
    padding: 40px 25px;
    border-radius: var(--radius-xl);
    flex: 1 1 280px;
    max-width: 340px;
    border: 1px solid #eee;
    text-align: center;
    transition: all 0.3s ease;
    position: relative;
}

.version-card:hover {
    border-color: var(--primary-red);
    box-shadow: var(--shadow-md);
    transform: translateY(-5px);
}

.version-card-badge {
    position: absolute;
    top: -12px;
    right: -12px;
    background: var(--primary-red);
    color: #fff;
    font-size: 0.75rem;
    font-weight: 700;
    padding: 5px 15px;
    border-radius: 20px;
    letter-spacing: 0.5px;
}

.version-card h3 {
    font-size: 1.7rem;
    margin-bottom: 18px;
    font-weight: 700;
}

.version-card-desc {
    color: var(--text-secondary);
    line-height: 1.8;
    margin-bottom: 20px;
    min-height: 90px;
}

.version-card-meta {
    display: flex;
    flex-direction: column;
    gap: 6px;
    margin-bottom: 25px;
    font-size: 0.9rem;
    color: #4b5563;
    text-align: left;
    padding-left: 20px;
}

.btn-version {
    display: inline-block;
    padding: 14px 30px;
    border-radius: var(--radius-sm);
    text-decoration: none;
    font-weight: 700;
    transition: all 0.3s ease;
    width: 100%;
    box-sizing: border-box;
}

.btn-version-primary {
    background: var(--primary-red);
    color: #fff;
    box-shadow: 0 8px 20px rgba(239, 68, 68, 0.2);
}

.btn-version-primary:hover {
    background: var(--primary-dark);
    transform: translateY(-2px);
}

.btn-version-outline {
    background: #fff;
    color: var(--primary-red);
    border: 2px solid var(--primary-red);
}

.btn-version-outline:hover {
    background: var(--primary-red);
    color: #fff;
}

.version-footnote {
    margin-top: 40px;
    font-size: 0.9rem;
    color: #9ca3af;
}

/* ========== 系统要求速查版块 ========== */
.sys-req {
    padding: 70px 8%;
    background: #fcfcfc;
    text-align: center;
}

.sys-req h2 {
    font-size: 2.5rem;
    font-weight: 700;
    margin-bottom: 40px;
}

.sys-req h2 span {
    color: var(--primary-red);
}

.req-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 20px;
    max-width: 1000px;
    margin: 0 auto 30px;
}

.req-item {
    background: #fff;
    padding: 20px 25px;
    border-radius: var(--radius-md);
    border: 1px solid #eee;
    text-align: left;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.req-item strong {
    font-weight: 700;
    color: var(--text-main);
    font-size: 0.95rem;
}

.req-item span {
    color: var(--text-secondary);
    font-size: 0.9rem;
}

.req-note {
    font-size: 0.9rem;
    color: #9ca3af;
    margin-top: 10px;
}

/* ========== 页脚 (与首页统一) ========== */
footer {
    background: #111111;
    color: #ffffff;
    padding: 80px 8% 40px;
}

.footer-container {
    display: grid;
    grid-template-columns: 1.8fr 1fr 1fr 1fr 1fr;
    gap: 40px;
}

.footer-logo-section img {
    height: 35px;
    margin-bottom: 20px;
}

.footer-logo-section p {
    color: #999;
    font-size: 14px;
    margin-bottom: 8px;
}

.footer-domain {
    color: var(--primary-red) !important;
    font-weight: 600;
}

.footer-column h3 {
    color: var(--primary-red);
    font-size: 1.1rem;
    font-weight: 700;
    margin-bottom: 24px;
    position: relative;
    padding-bottom: 12px;
}

.footer-column h3::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 0;
    width: 30px;
    height: 2px;
    background: var(--primary-red);
    border-radius: 2px;
}

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

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

.footer-column ul li a {
    color: #cccccc;
    text-decoration: none;
    font-size: 14px;
    transition: color 0.3s;
}

.footer-column ul li a:hover {
    color: var(--primary-red);
}

.footer-bottom {
    margin-top: 60px;
    padding-top: 30px;
    border-top: 1px solid #222;
    display: flex;
    justify-content: space-between;
    align-items: center;
    font-size: 13px;
    color: #888;
    flex-wrap: wrap;
    gap: 16px;
}

.footer-socials {
    display: flex;
    gap: 20px;
}

.footer-socials a {
    color: #888;
    text-decoration: none;
    transition: color 0.3s;
}

.footer-socials a:hover {
    color: #fff;
}

/* ========== 响应式设计 ========== */
@media (max-width: 1024px) {
    .main-dl-card {
        flex-direction: column;
        text-align: center;
        padding: 40px 30px;
        gap: 30px;
    }
    .os-info {
        text-align: center;
    }
    .btn-dl-large {
        width: 100%;
    }
    .footer-container {
        grid-template-columns: 1fr 1fr;
        gap: 40px;
    }
    .footer-logo-section {
        grid-column: span 2;
        text-align: center;
    }
    .version-cards,
    .steps-grid,
    .advantage-grid {
        justify-content: center;
    }
}

@media (max-width: 768px) {
    .dl-hero h1 {
        font-size: 2.5rem;
    }
    .dl-hero-desc {
        font-size: 1rem;
    }
    .advantage-section h2,
    .install-guide h2,
    .version-compare h2 {
        font-size: 2.2rem;
    }
    .main-dl-card {
        padding: 30px 20px;
    }
    .req-grid {
        grid-template-columns: 1fr;
    }
}

@media (max-width: 480px) {
    .btn-dl-large {
        padding: 16px 20px;
        font-size: 1rem;
    }
}