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

body {
    font-family: 'Inter', system-ui, -apple-system, 'Segoe UI', Roboto, Helvetica, sans-serif;
    background-color: #0A0F1E;
    color: #EFF3FC;
    line-height: 1.5;
    scroll-behavior: smooth;
}

:root {
    --primary: #2A6DFF;
    --primary-dark: #1E52CC;
    --primary-glow: rgba(42, 109, 255, 0.25);
    --bg-card: #111827;
    --bg-elevated: #1E293B;
    --border-dim: #2D3A5E;
    --text-muted: #A0B3D9;
    --trust-bg: #F3F6FC;
    --trust-text: #0A1428;
}

html {
    scroll-behavior: smooth;
}

a {
    text-decoration: none;
    color: inherit;
    transition: all 0.2s ease;
}

.container {
    max-width: 1280px;
    margin: 0 auto;
    padding: 0 24px;
}

/* Header 吸顶 */
header {
    background: rgba(10, 15, 30, 0.92);
    backdrop-filter: blur(12px);
    position: sticky;
    top: 0;
    z-index: 100;
    border-bottom: 1px solid rgba(45, 58, 94, 0.5);
}

.navbar {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 16px 0;
    flex-wrap: wrap;
}

.logo {
    display: flex;
    align-items: center;
    gap: 10px;
    font-size: 1.6rem;
    font-weight: 700;
}

.logo i {
    font-size: 2rem;
    color: var(--primary);
    transform: rotate(-20deg);
}

.nav-links {
    display: flex;
    gap: 32px;
    align-items: center;
}

.nav-links a {
    font-weight: 500;
    font-size: 1rem;
}

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

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

.btn-outline {
    border: 1.5px solid var(--primary);
    padding: 8px 20px;
    border-radius: 40px;
    font-weight: 600;
}

.btn-primary {
    background: var(--primary);
    padding: 8px 24px;
    border-radius: 40px;
    font-weight: 600;
    box-shadow: 0 4px 12px rgba(42, 109, 255, 0.3);
}

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

.btn-outline:hover {
    background: rgba(42, 109, 255, 0.1);
}

/* 移动端汉堡菜单 */
#menu-toggle {
    display: none;
}

.menu-icon {
    display: none;
    font-size: 1.8rem;
    cursor: pointer;
}

/* 页面 Hero */
.page-hero {
    padding: 80px 0 60px;
    position: relative;
    overflow: hidden;
}

.page-hero-bg {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: radial-gradient(circle at 30% 50%, #0f172f, #030614);
    z-index: -1;
}

.page-hero-bg::before {
    content: "";
    position: absolute;
    width: 200%;
    height: 200%;
    top: -50%;
    left: -50%;
    background: radial-gradient(circle, rgba(42,109,255,0.15) 1px, transparent 1px);
    background-size: 50px 50px;
    animation: drift 40s linear infinite;
    pointer-events: none;
}

@keyframes drift {
    0% { transform: translate(0, 0); }
    100% { transform: translate(20%, 20%); }
}

.page-hero-content {
    text-align: center;
    position: relative;
    z-index: 2;
}

.page-hero h1 {
    font-size: 3.2rem;
    font-weight: 800;
    background: linear-gradient(135deg, #FFFFFF, #7AA9FF);
    -webkit-background-clip: text;
    background-clip: text;
    color: transparent;
    margin-bottom: 20px;
}

.page-hero .sub {
    font-size: 1.2rem;
    color: var(--text-muted);
    margin-bottom: 28px;
}

.hero-meta {
    display: flex;
    justify-content: center;
    gap: 28px;
    flex-wrap: wrap;
    font-size: 0.85rem;
    color: var(--text-muted);
}

.hero-meta span i {
    margin-right: 6px;
    color: var(--primary);
}

/* 章节标题 */
.section-title {
    font-size: 2.2rem;
    font-weight: 700;
    text-align: center;
    margin-bottom: 48px;
}

.section-subtitle {
    text-align: center;
    color: var(--text-muted);
    font-size: 1.1rem;
    margin-top: -32px;
    margin-bottom: 48px;
}

/* 平台下载卡片网格 */
.download-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 30px;
    margin: 40px 0 80px;
}

.download-card {
    background: var(--bg-card);
    border-radius: 32px;
    padding: 36px 32px;
    border: 1px solid var(--border-dim);
    transition: all 0.3s;
    position: relative;
}

.download-card:hover {
    transform: translateY(-4px);
    box-shadow: 0 20px 35px -12px rgba(0,0,0,0.5);
    border-color: var(--primary);
}

.download-card-icon {
    width: 88px;
    height: 88px;
    border-radius: 24px;
    background: linear-gradient(135deg, rgba(42,109,255,0.2), rgba(42,109,255,0.05));
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 2.8rem;
    color: var(--primary);
    margin-bottom: 24px;
}

.download-card h3 {
    font-size: 1.6rem;
    margin-bottom: 8px;
}

.download-card .os-info {
    color: var(--text-muted);
    font-size: 0.9rem;
    margin-bottom: 20px;
}

.download-specs {
    list-style: none;
    margin-bottom: 24px;
}

.download-specs li {
    margin: 8px 0;
    display: flex;
    align-items: center;
    gap: 8px;
    font-size: 0.95rem;
}

.download-specs li i {
    color: #6EE7B7;
    font-size: 0.85rem;
}

.download-actions {
    display: flex;
    flex-direction: column;
    gap: 10px;
}

.download-actions .btn-primary {
    display: block;
    text-align: center;
    padding: 12px;
}

.download-actions .btn-outline {
    display: block;
    text-align: center;
    padding: 12px;
}

.download-version {
    color: var(--text-muted);
    font-size: 0.82rem;
    text-align: center;
    margin-top: 10px;
}

/* 简易系统要求 */
.requirements-section {
    background: var(--bg-elevated);
    border-radius: 48px;
    padding: 56px 48px;
    margin: 40px 0;
}

.requirements-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
    gap: 32px;
}

.requirement-item {
    text-align: center;
}

.requirement-item i {
    font-size: 2.2rem;
    color: var(--primary);
    margin-bottom: 16px;
    display: block;
}

.requirement-item h4 {
    font-size: 1.1rem;
    margin-bottom: 8px;
}

.requirement-item p {
    color: var(--text-muted);
    font-size: 0.92rem;
}

/* 安装步骤 */
.steps-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
    gap: 24px;
    margin: 48px 0;
}

.step-card {
    background: var(--bg-card);
    border-radius: 28px;
    padding: 32px 28px;
    border: 1px solid var(--border-dim);
    position: relative;
}

.step-number {
    width: 40px;
    height: 40px;
    background: var(--primary);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-weight: 700;
    font-size: 1.1rem;
    margin-bottom: 16px;
}

.step-card h3 {
    font-size: 1.35rem;
    margin-bottom: 12px;
}

.step-card p {
    color: var(--text-muted);
    font-size: 0.95rem;
}

/* FAQ/提示区 */
.faq-list {
    margin: 48px 0 64px;
    display: flex;
    flex-direction: column;
    gap: 16px;
}

details {
    background: var(--bg-elevated);
    border-radius: 24px;
    padding: 16px 24px;
    border: 1px solid var(--border-dim);
}

summary {
    font-weight: 700;
    font-size: 1.15rem;
    cursor: pointer;
    list-style: none;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

summary::-webkit-details-marker {
    display: none;
}

summary:after {
    content: "➕";
    font-size: 1rem;
}

details[open] summary:after {
    content: "➖";
}

details p {
    margin-top: 16px;
    padding-left: 8px;
    border-left: 3px solid var(--primary);
    color: var(--text-muted);
}

/* Footer */
footer {
    background: #050A15;
    padding: 48px 0 24px;
    margin-top: 80px;
}

.footer-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 40px;
    margin-bottom: 32px;
}

.footer-col h4 {
    font-size: 1.1rem;
    margin-bottom: 16px;
    color: #fff;
}

.footer-col a {
    display: block;
    color: var(--text-muted);
    font-size: 0.92rem;
    margin: 8px 0;
}

.footer-col a:hover {
    color: var(--primary);
}

.footer-col .logo {
    font-size: 1.4rem;
    margin-bottom: 12px;
}

.footer-col p {
    color: var(--text-muted);
    font-size: 0.92rem;
    line-height: 1.6;
}

.social-icons {
    display: flex;
    gap: 16px;
    margin-top: 16px;
}

.social-icons a {
    font-size: 1.4rem;
    margin: 0;
    display: inline-block;
}

.copyright {
    text-align: center;
    color: var(--text-muted);
    font-size: 0.85rem;
    border-top: 1px solid var(--border-dim);
    padding-top: 24px;
}

/* 移动端响应 */
@media (max-width: 768px) {
    .navbar {
        flex-wrap: wrap;
    }
    .nav-links {
        display: none;
        width: 100%;
        flex-direction: column;
        padding: 24px 0;
        gap: 20px;
    }
    .menu-icon {
        display: block;
    }
    #menu-toggle:checked ~ .nav-links {
        display: flex;
    }
    .page-hero h1 {
        font-size: 2.2rem;
    }
    .section-title {
        font-size: 1.8rem;
    }
    .requirements-section {
        padding: 36px 20px;
    }
}

@media (min-width: 769px) {
    .nav-links {
        display: flex !important;
    }
}

a, .btn-primary, .btn-outline {
    cursor: pointer;
}