/* ─── 全局样式 ─── */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

:root {
    --bg: #0a0a0f;
    --bg-card: #12121a;
    --bg-alt: #0e0e14;
    --border: #1f1f2e;
    --text: #e4e4ed;
    --text-muted: #7a7a8e;
    --primary: #6366f1;
    --primary-glow: rgba(99, 102, 241, 0.15);
    --accent: #22d3ee;
    --radius: 14px;
}

body {
    font-family: 'SF Pro Display', -apple-system, BlinkMacSystemFont, 'PingFang SC', 'Hiragino Sans GB', sans-serif;
    background: var(--bg);
    color: var(--text);
    line-height: 1.7;
    -webkit-font-smoothing: antialiased;
}

.container {
    max-width: 1000px;
    margin: 0 auto;
    padding: 0 28px;
}

/* ─── 导航栏 ─── */
.navbar {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    padding: 18px 32px;
    display: flex;
    align-items: center;
    justify-content: space-between;
    background: rgba(10, 10, 15, 0.9);
    backdrop-filter: blur(20px);
    border-bottom: 1px solid var(--border);
    z-index: 100;
}

.nav-brand-link {
    text-decoration: none;
    color: inherit;
}

.nav-brand {
    font-size: 19px;
    font-weight: 700;
    color: #fff;
    letter-spacing: -0.02em;
}

.nav-cta {
    padding: 10px 20px;
    background: var(--primary);
    color: #fff;
    border-radius: 8px;
    font-size: 14px;
    font-weight: 600;
    text-decoration: none;
    transition: all 0.2s;
}

.nav-cta:hover {
    background: #5254cc;
    transform: translateY(-1px);
}

/* ─── Hero ─── */
.hero {
    padding: 180px 0 100px;
    position: relative;
}

.hero::before {
    content: '';
    position: absolute;
    top: 0;
    left: 50%;
    transform: translateX(-50%);
    width: 600px;
    height: 600px;
    background: radial-gradient(circle, var(--primary-glow) 0%, transparent 70%);
    pointer-events: none;
}

.hero-badge {
    display: inline-block;
    padding: 8px 16px;
    background: var(--primary-glow);
    border: 1px solid rgba(99, 102, 241, 0.3);
    border-radius: 20px;
    font-size: 13px;
    font-weight: 500;
    color: var(--primary);
    margin-bottom: 28px;
}

.hero-title {
    font-size: 56px;
    font-weight: 800;
    color: #fff;
    line-height: 1.2;
    margin-bottom: 24px;
    letter-spacing: -0.03em;
}

.hero-desc {
    font-size: 18px;
    color: var(--text-muted);
    max-width: 520px;
    line-height: 1.8;
}

.hero-btn {
    display: inline-block;
    margin-top: 32px;
    padding: 14px 32px;
    background: var(--primary);
    color: #fff;
    border-radius: 8px;
    font-size: 16px;
    font-weight: 600;
    text-decoration: none;
    transition: all 0.2s;
}

.hero-btn:hover {
    background: #5254cc;
    transform: translateY(-2px);
}

/* ─── 区块 ─── */
.section {
    padding: 100px 0;
}

.section-alt {
    background: var(--bg-alt);
    border-top: 1px solid var(--border);
    border-bottom: 1px solid var(--border);
}

.section-title {
    font-size: 32px;
    font-weight: 700;
    color: #fff;
    margin-bottom: 14px;
    letter-spacing: -0.02em;
}

.section-desc {
    font-size: 16px;
    color: var(--text-muted);
    margin-bottom: 48px;
    max-width: 560px;
    line-height: 1.7;
}

/* ─── 角色卡片 ─── */
.role-cards {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 20px;
    margin-bottom: 32px;
}

.role-card {
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 32px 28px;
    transition: all 0.3s;
}

.role-card:hover {
    border-color: var(--primary);
    transform: translateY(-4px);
    box-shadow: 0 20px 40px -20px rgba(99, 102, 241, 0.2);
}

.card-icon {
    font-size: 32px;
    margin-bottom: 16px;
}

.role-card h3 {
    font-size: 18px;
    color: #fff;
    margin-bottom: 10px;
    font-weight: 600;
}

.role-card p {
    font-size: 14px;
    color: var(--text-muted);
    line-height: 1.7;
}

/* ─── 标签 ─── */
.tag-row {
    display: flex;
    gap: 12px;
    flex-wrap: wrap;
}

.tag {
    padding: 10px 20px;
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: 24px;
    font-size: 13px;
    color: var(--text-muted);
    font-weight: 500;
}

/* ─── 信息卡片 ─── */
.info-cards {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 20px;
}

.info-card {
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 32px;
    transition: all 0.3s;
}

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

.info-icon {
    font-size: 28px;
    margin-bottom: 16px;
}

.info-card h3 {
    font-size: 17px;
    color: #fff;
    margin-bottom: 10px;
    font-weight: 600;
}

.info-card p {
    font-size: 14px;
    color: var(--text-muted);
    line-height: 1.7;
}

/* ─── 步骤 ─── */
.steps {
    display: flex;
    flex-direction: column;
    gap: 16px;
}

.step {
    display: flex;
    align-items: center;
    gap: 24px;
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 28px 32px;
    transition: border-color 0.2s;
}

.step:hover {
    border-color: var(--primary);
}

.step-number {
    width: 44px;
    height: 44px;
    min-width: 44px;
    background: linear-gradient(135deg, var(--primary), #818cf8);
    color: #fff;
    border-radius: 12px;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 18px;
    font-weight: 700;
}

.step-content h3 {
    font-size: 18px;
    color: #fff;
    margin-bottom: 6px;
    font-weight: 600;
}

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

/* ─── 页脚 ─── */
.footer {
    padding: 40px 0;
    border-top: 1px solid var(--border);
    text-align: center;
}

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

/* ─── 动画 ─── */
.fade-in {
    opacity: 0;
    transform: translateY(20px);
    transition: opacity 0.6s ease, transform 0.6s ease;
}

.fade-in.visible {
    opacity: 1;
    transform: translateY(0);
}

/* ─── 响应式 ─── */
@media (max-width: 768px) {
    .hero-title {
        font-size: 36px;
    }
    .hero-desc {
        font-size: 16px;
    }
    .role-cards {
        grid-template-columns: 1fr;
    }
    .section-title {
        font-size: 26px;
    }
    .info-cards {
        grid-template-columns: 1fr;
    }
    .step {
        flex-direction: column;
        align-items: flex-start;
    }
    .navbar {
        padding: 14px 20px;
    }
}