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

:root {
    --primary: #2563eb;
    --secondary: #7c3aed;
    --accent: #f59e0b;
    --dark: #1e293b;
    --light: #f8fafc;
    --gray: #64748b;
    --success: #10b981;
    --warning: #f59e0b;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'PingFang SC', 'Hiragino Sans GB', 'Microsoft YaHei', sans-serif;
    line-height: 1.6;
    color: var(--dark);
    background: var(--light);
}

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

/* Navbar */
.navbar {
    background: white;
    box-shadow: 0 2px 10px rgba(0,0,0,0.1);
    position: sticky;
    top: 0;
    z-index: 100;
    padding: 1rem 0;
}

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

.navbar h1 {
    font-size: 1.5rem;
    color: var(--primary);
}

.nav-links {
    display: flex;
    gap: 2rem;
}

.nav-links a {
    color: var(--dark);
    text-decoration: none;
    font-weight: 500;
    transition: color 0.3s;
}

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

/* Hero */
.hero {
    background: linear-gradient(135deg, var(--primary), var(--secondary));
    color: white;
    padding: 4rem 0;
    text-align: center;
}

.hero h1 {
    font-size: 3rem;
    margin-bottom: 1rem;
}

.hero h2 {
    font-size: 1.5rem;
    font-weight: 400;
    margin-bottom: 1rem;
}

.hero .subtitle {
    font-size: 1.2rem;
    opacity: 0.9;
}

/* Sections */
.section {
    background: white;
    margin: 2rem 0;
    padding: 3rem;
    border-radius: 12px;
    box-shadow: 0 4px 20px rgba(0,0,0,0.08);
}

.section h2 {
    font-size: 2rem;
    color: var(--primary);
    margin-bottom: 2rem;
    border-bottom: 3px solid var(--accent);
    padding-bottom: 0.5rem;
}

.subsection {
    margin: 2rem 0;
}

.subsection h3 {
    font-size: 1.5rem;
    color: var(--secondary);
    margin-bottom: 1.5rem;
}

/* Stats Grid */
.stats-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 2rem;
    margin: 2rem 0;
}

.stat-card {
    background: linear-gradient(135deg, var(--primary), var(--secondary));
    color: white;
    padding: 2rem;
    border-radius: 12px;
    text-align: center;
}

.stat-card h3 {
    font-size: 3rem;
    margin-bottom: 0.5rem;
}

.stat-card p {
    font-size: 1.1rem;
}

/* Feature Cards */
.feature-card {
    background: var(--light);
    padding: 2rem;
    border-radius: 12px;
    margin: 1.5rem 0;
    border-left: 4px solid var(--primary);
}

.feature-card h4 {
    font-size: 1.3rem;
    color: var(--primary);
    margin-bottom: 1rem;
}

.feature-card ul {
    margin-left: 1.5rem;
    margin-top: 1rem;
}

.feature-card .example {
    background: white;
    padding: 1rem;
    border-radius: 8px;
    margin-top: 1rem;
    font-style: italic;
}

blockquote {
    border-left: 4px solid var(--accent);
    padding-left: 1rem;
    margin: 1rem 0;
    font-style: italic;
    color: var(--gray);
}

/* Boxes */
.highlight-box {
    background: linear-gradient(135deg, #fef3c7, #fde68a);
    padding: 2rem;
    border-radius: 12px;
    margin: 2rem 0;
    border-left: 4px solid var(--accent);
}

.insight-box {
    background: #eff6ff;
    padding: 2rem;
    border-radius: 12px;
    margin: 2rem 0;
    border-left: 4px solid var(--primary);
}

.warning-box {
    background: #fef2f2;
    padding: 1.5rem;
    border-radius: 8px;
    margin: 1.5rem 0;
    border-left: 4px solid #ef4444;
}

.principle-box {
    background: #f0fdf4;
    padding: 1.5rem;
    border-radius: 8px;
    margin: 1.5rem 0;
    border-left: 4px solid var(--success);
}

/* Case Study */
.case-study {
    background: white;
    border: 2px solid var(--primary);
    padding: 2rem;
    border-radius: 12px;
    margin: 2rem 0;
}

.case-study h4 {
    color: var(--primary);
    margin-bottom: 1rem;
}

.case-study .result {
    background: var(--success);
    color: white;
    padding: 1rem;
    border-radius: 8px;
    margin-top: 1rem;
    font-weight: bold;
}

/* Metrics Table */
.metrics-table {
    margin: 2rem 0;
}

.metric-row {
    display: grid;
    grid-template-columns: 2fr 1fr 2fr;
    gap: 1rem;
    padding: 1rem;
    background: var(--light);
    margin-bottom: 0.5rem;
    border-radius: 8px;
    align-items: center;
}

.metric-name {
    font-weight: 600;
}

.metric-value {
    font-size: 1.3rem;
    color: var(--primary);
    font-weight: bold;
    text-align: center;
}

.metric-note {
    color: var(--gray);
    font-size: 0.9rem;
}

/* Funnel */
.funnel-diagram {
    display: flex;
    flex-direction: column;
    gap: 1.5rem;
    margin: 2rem 0;
}

.funnel-stage {
    background: var(--light);
    padding: 2rem;
    border-radius: 12px;
    border-left: 4px solid var(--primary);
}

.funnel-stage h4 {
    color: var(--primary);
    margin-bottom: 1rem;
}

/* Platform Grid */
.platform-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 2rem;
    margin: 2rem 0;
}

.platform-card {
    padding: 2rem;
    border-radius: 12px;
    color: white;
}

.platform-card.youtube {
    background: linear-gradient(135deg, #ff0000, #cc0000);
}

.platform-card.tiktok {
    background: linear-gradient(135deg, #000000, #ee1d52);
}

.platform-card.linkedin {
    background: linear-gradient(135deg, #0077b5, #00a0dc);
}

.platform-tag {
    background: rgba(255,255,255,0.2);
    display: inline-block;
    padding: 0.3rem 0.8rem;
    border-radius: 20px;
    font-size: 0.9rem;
    margin-bottom: 1rem;
}

.platform-note {
    margin-top: 1rem;
    font-size: 0.9rem;
    opacity: 0.9;
}

/* Hook Grid */
.hook-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 1.5rem;
    margin: 2rem 0;
}

.hook-card {
    background: var(--light);
    padding: 1.5rem;
    border-radius: 12px;
    border-top: 4px solid var(--accent);
}

.hook-card h4 {
    color: var(--secondary);
    margin-bottom: 1rem;
}

.hook-card .example {
    background: white;
    padding: 1rem;
    border-radius: 8px;
    margin-top: 1rem;
    font-style: italic;
    color: var(--primary);
}

/* Checklist */
.checklist {
    margin: 2rem 0;
}

.checklist-item {
    display: flex;
    gap: 1rem;
    padding: 1rem;
    background: var(--light);
    margin-bottom: 0.5rem;
    border-radius: 8px;
}

.checklist-item .check {
    color: var(--success);
    font-size: 1.5rem;
    font-weight: bold;
}

/* Timeline */
.timeline {
    margin: 2rem 0;
    position: relative;
    padding-left: 2rem;
}

.timeline::before {
    content: '';
    position: absolute;
    left: 0;
    top: 0;
    bottom: 0;
    width: 3px;
    background: var(--primary);
}

.timeline-item {
    margin-bottom: 2rem;
    position: relative;
}

.timeline-marker {
    background: var(--primary);
    color: white;
    padding: 0.5rem 1rem;
    border-radius: 20px;
    display: inline-block;
    margin-bottom: 0.5rem;
    font-weight: 600;
}

.timeline-content {
    background: var(--light);
    padding: 1.5rem;
    border-radius: 8px;
}

/* Tips Grid */
.tips-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 1.5rem;
    margin: 2rem 0;
}

.tip-card {
    background: var(--light);
    padding: 1.5rem;
    border-radius: 12px;
    border-left: 4px solid var(--success);
}

.tip-card h4 {
    color: var(--secondary);
    margin-bottom: 0.5rem;
}

/* Tools Grid */
.tools-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 2rem;
    margin: 2rem 0;
}

.tool-card {
    background: var(--light);
    padding: 2rem;
    border-radius: 12px;
    text-align: center;
    border-top: 4px solid var(--primary);
}

.tool-card h4 {
    color: var(--primary);
    font-size: 1.5rem;
    margin-bottom: 0.5rem;
}

.tool-price {
    color: var(--accent);
    font-weight: bold;
    margin-bottom: 1rem;
}

/* Budget Box */
.budget-box {
    background: var(--light);
    padding: 2rem;
    border-radius: 12px;
    margin: 2rem 0;
}

.budget-tier {
    padding: 1.5rem;
    margin: 1rem 0;
    border-radius: 8px;
    background: white;
}

.budget-tier.highlight {
    background: linear-gradient(135deg, #dcfce7, #bbf7d0);
    border-left: 4px solid var(--success);
}

/* Footer */
footer {
    background: var(--dark);
    color: white;
    text-align: center;
    padding: 2rem 0;
    margin-top: 4rem;
}

/* Responsive */
@media (max-width: 768px) {
    .hero h1 {
        font-size: 2rem;
    }
    
    .nav-links {
        flex-direction: column;
        gap: 0.5rem;
    }
    
    .metric-row {
        grid-template-columns: 1fr;
        text-align: center;
    }
}