/* CSS Reset and Base Styles */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

:root {
    /* Color Palette */
    --color-primary: #2563eb;
    --color-primary-dark: #1e40af;
    --color-secondary: #7c3aed;
    --color-accent: #06b6d4;
    --color-success: #10b981;
    --color-text: #1f2937;
    --color-text-light: #6b7280;
    --color-bg: #ffffff;
    --color-bg-alt: #f9fafb;
    --color-border: #e5e7eb;
    --color-shadow: rgba(0, 0, 0, 0.1);

    /* Typography */
    --font-sans: -apple-system, BlinkMacSystemFont, "Segoe UI", "Noto Sans SC", "Microsoft YaHei", sans-serif;
    --font-mono: "SF Mono", "Consolas", monospace;

    /* Spacing */
    --spacing-xs: 0.5rem;
    --spacing-sm: 1rem;
    --spacing-md: 2rem;
    --spacing-lg: 4rem;
    --spacing-xl: 6rem;

    /* Border Radius */
    --radius-sm: 0.5rem;
    --radius-md: 1rem;
    --radius-lg: 1.5rem;

    /* Transitions */
    --transition-fast: 150ms ease;
    --transition-base: 250ms ease;
}

html {
    font-size: 16px;
    scroll-behavior: smooth;
}

body {
    font-family: var(--font-sans);
    color: var(--color-text);
    background-color: var(--color-bg);
    line-height: 1.6;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

/* Container */
.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 var(--spacing-sm);
}

/* Header */
.header {
    background: linear-gradient(135deg, var(--color-primary) 0%, var(--color-secondary) 100%);
    color: white;
    padding: var(--spacing-md) 0;
    text-align: center;
}

.logo {
    font-size: 2.5rem;
    font-weight: 700;
    margin-bottom: var(--spacing-xs);
    letter-spacing: -0.02em;
}

.tagline {
    font-size: 1.125rem;
    opacity: 0.95;
    font-weight: 300;
}

/* Hero Section */
.hero {
    padding: var(--spacing-xl) 0;
    background-color: var(--color-bg-alt);
    text-align: center;
}

.hero-title {
    font-size: 2.25rem;
    font-weight: 700;
    margin-bottom: var(--spacing-sm);
    line-height: 1.2;
    color: var(--color-text);
}

.hero-subtitle {
    font-size: 1.25rem;
    color: var(--color-text-light);
    margin-bottom: var(--spacing-lg);
}

.features-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: var(--spacing-md);
    margin-top: var(--spacing-lg);
}

.feature-card {
    background: white;
    padding: var(--spacing-md);
    border-radius: var(--radius-lg);
    box-shadow: 0 4px 6px var(--color-shadow);
    transition: transform var(--transition-base), box-shadow var(--transition-base);
}

.feature-card:hover {
    transform: translateY(-4px);
    box-shadow: 0 12px 24px var(--color-shadow);
}

.feature-icon {
    font-size: 3rem;
    margin-bottom: var(--spacing-sm);
}

.feature-card h3 {
    font-size: 1.5rem;
    margin-bottom: var(--spacing-xs);
    color: var(--color-primary);
}

.feature-card p {
    color: var(--color-text-light);
    line-height: 1.8;
}

/* Features Section */
.features {
    padding: var(--spacing-xl) 0;
    background-color: var(--color-bg);
}

.section-title {
    font-size: 2rem;
    font-weight: 700;
    text-align: center;
    margin-bottom: var(--spacing-lg);
    color: var(--color-text);
}

.feature-list {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-md);
    max-width: 900px;
    margin: 0 auto;
}

.feature-item {
    display: flex;
    gap: var(--spacing-md);
    padding: var(--spacing-md);
    background: var(--color-bg-alt);
    border-radius: var(--radius-md);
    border-left: 4px solid var(--color-primary);
}

.feature-number {
    font-size: 2rem;
    font-weight: 700;
    color: var(--color-primary);
    opacity: 0.3;
    min-width: 60px;
}

.feature-content h3 {
    font-size: 1.5rem;
    margin-bottom: var(--spacing-xs);
    color: var(--color-text);
}

.feature-content p {
    color: var(--color-text-light);
    margin-bottom: var(--spacing-sm);
}

.feature-tags {
    display: flex;
    flex-wrap: wrap;
    gap: var(--spacing-xs);
    list-style: none;
}

.feature-tags li {
    padding: 0.375rem 0.875rem;
    background-color: var(--color-primary);
    color: white;
    border-radius: 2rem;
    font-size: 0.875rem;
    font-weight: 500;
}

/* Comparison Section */
.comparison {
    padding: var(--spacing-xl) 0;
    background: linear-gradient(180deg, var(--color-bg-alt) 0%, white 100%);
}

.comparison-table {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: var(--spacing-md);
    max-width: 800px;
    margin: 0 auto;
}

.comparison-column {
    background: white;
    border-radius: var(--radius-lg);
    padding: var(--spacing-md);
    box-shadow: 0 4px 6px var(--color-shadow);
    border: 2px solid var(--color-border);
    transition: transform var(--transition-base), box-shadow var(--transition-base);
}

.comparison-column:hover {
    transform: translateY(-4px);
    box-shadow: 0 12px 24px var(--color-shadow);
}

.comparison-column.featured {
    border-color: var(--color-primary);
    position: relative;
}

.plan-header {
    text-align: center;
    padding-bottom: var(--spacing-md);
    border-bottom: 2px solid var(--color-border);
    margin-bottom: var(--spacing-md);
}

.badge {
    display: inline-block;
    background: linear-gradient(135deg, var(--color-primary) 0%, var(--color-secondary) 100%);
    color: white;
    padding: 0.375rem 1rem;
    border-radius: 2rem;
    font-size: 0.875rem;
    font-weight: 600;
    margin-bottom: var(--spacing-sm);
}

.plan-header h3 {
    font-size: 1.75rem;
    margin-bottom: var(--spacing-xs);
    color: var(--color-text);
}

.plan-subtitle {
    color: var(--color-text-light);
    font-size: 1rem;
}

.plan-features {
    list-style: none;
}

.plan-features li {
    padding: 0.75rem 0;
    padding-left: 2rem;
    position: relative;
    border-bottom: 1px solid var(--color-border);
}

.plan-features li:last-child {
    border-bottom: none;
}

.plan-features li::before {
    content: '';
    position: absolute;
    left: 0;
    top: 50%;
    transform: translateY(-50%);
    width: 1.25rem;
    height: 1.25rem;
    border-radius: 50%;
}

.plan-features li.included::before {
    background-color: var(--color-success);
    content: '✓';
    color: white;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 0.875rem;
    font-weight: 700;
}

.plan-features li.not-included {
    color: var(--color-text-light);
    opacity: 0.6;
}

.plan-features li.not-included::before {
    background-color: var(--color-border);
    content: '−';
    color: var(--color-text-light);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1rem;
}

.plan-note {
    text-align: center;
    margin-top: var(--spacing-md);
    padding: var(--spacing-sm);
    background: linear-gradient(135deg, rgba(37, 99, 235, 0.1) 0%, rgba(124, 58, 237, 0.1) 100%);
    border-radius: var(--radius-sm);
    font-weight: 600;
    color: var(--color-primary);
}

/* Requirements Section */
.requirements {
    padding: var(--spacing-xl) 0;
    background-color: var(--color-bg-alt);
}

.requirements-content {
    max-width: 700px;
    margin: 0 auto;
    background: white;
    padding: var(--spacing-md);
    border-radius: var(--radius-md);
    box-shadow: 0 2px 4px var(--color-shadow);
}

.requirements-content p {
    padding: var(--spacing-sm) 0;
    border-bottom: 1px solid var(--color-border);
    color: var(--color-text-light);
}

.requirements-content p:last-child {
    border-bottom: none;
}

.requirements-content strong {
    color: var(--color-text);
    font-weight: 600;
}

/* Footer */
.footer {
    background-color: var(--color-text);
    color: white;
    padding: var(--spacing-md) 0;
}

.footer-content {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: var(--spacing-sm);
}

.footer-company {
    font-size: 0.875rem;
    opacity: 0.8;
}

.footer-icp {
    display: flex;
    align-items: center;
    gap: var(--spacing-xs);
    font-size: 0.875rem;
    flex-wrap: wrap;
    justify-content: center;
}

.icp-link {
    color: rgba(255, 255, 255, 0.8);
    text-decoration: none;
    display: inline-flex;
    align-items: center;
    gap: 0.25rem;
    transition: color var(--transition-fast);
}

.icp-link:hover {
    color: white;
    text-decoration: underline;
}

.icp-icon {
    font-size: 1rem;
}

.icp-text {
    white-space: nowrap;
}

.icp-divider {
    color: rgba(255, 255, 255, 0.4);
    padding: 0 0.25rem;
}

/* Responsive Design */
@media (max-width: 768px) {
    .hero-title {
        font-size: 1.75rem;
    }

    .hero-subtitle {
        font-size: 1rem;
    }

    .features-grid {
        grid-template-columns: 1fr;
    }

    .feature-item {
        flex-direction: column;
    }

    .feature-number {
        min-width: auto;
    }

    .comparison-table {
        grid-template-columns: 1fr;
    }

    .section-title {
        font-size: 1.5rem;
    }

    .logo {
        font-size: 2rem;
    }

    .footer-icp {
        font-size: 0.75rem;
    }
}

@media (max-width: 480px) {
    :root {
        --spacing-lg: 3rem;
        --spacing-xl: 4rem;
    }

    .hero-title {
        font-size: 1.5rem;
    }

    .container {
        padding: 0 1rem;
    }
}