/* ===========================
   CSS Reset & Base Styles
   =========================== */

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

:root {
    /* Brand Colors */
    --python-blue: #3776AB;
    --python-yellow: #FFD43B;
    --developer-gray: #646464;
    --dark-gray: #2B2B2B;
    --light-gray: #F8F9FA;
    --white: #FFFFFF;
    --black: #000000;

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

    /* Typography */
    --font-system: -apple-system, BlinkMacSystemFont, "Segoe UI", "Inter", "Helvetica Neue", Arial, sans-serif;
    --font-mono: "JetBrains Mono", "Fira Code", "SF Mono", Monaco, "Cascadia Code", "Roboto Mono", Consolas, "Courier New", monospace;

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

html {
    scroll-behavior: smooth;
}

body {
    font-family: var(--font-system);
    font-size: 16px;
    line-height: 1.6;
    color: var(--dark-gray);
    background: var(--white);
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

/* ===========================
   Typography
   =========================== */

h1, h2, h3, h4, h5, h6 {
    font-weight: 700;
    line-height: 1.2;
    color: var(--black);
}

h1 {
    font-size: clamp(2.5rem, 8vw, 5rem);
}

h2 {
    font-size: clamp(2rem, 5vw, 3rem);
}

h3 {
    font-size: clamp(1.25rem, 3vw, 1.75rem);
}

p {
    margin-bottom: 1rem;
}

a {
    color: var(--python-blue);
    text-decoration: none;
    transition: color var(--transition-fast);
}

a:hover {
    color: var(--dark-gray);
}

code {
    font-family: var(--font-mono);
    font-size: 0.9em;
    background: var(--light-gray);
    padding: 0.2em 0.4em;
    border-radius: 3px;
}

pre {
    background: var(--dark-gray);
    color: var(--light-gray);
    padding: var(--spacing-md);
    border-radius: 8px;
    overflow-x: auto;
    font-family: var(--font-mono);
    font-size: 0.9rem;
    line-height: 1.5;
}

pre code {
    background: none;
    padding: 0;
    color: inherit;
}

/* Code Syntax Highlighting */
.code-comment {
    color: #8B949E;
}

.code-keyword {
    color: var(--python-yellow);
    font-weight: 600;
}

/* ===========================
   Layout
   =========================== */

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 var(--spacing-md);
}

section {
    padding: var(--spacing-xl) 0;
}

.section-title {
    text-align: center;
    margin-bottom: var(--spacing-lg);
    font-size: clamp(2rem, 5vw, 3rem);
}

/* ===========================
   Buttons
   =========================== */

.btn {
    display: inline-block;
    padding: 0.875rem 2rem;
    font-size: 1rem;
    font-weight: 600;
    text-align: center;
    border-radius: 6px;
    transition: all var(--transition-base);
    cursor: pointer;
    border: 2px solid transparent;
}

.btn-primary {
    background: var(--python-blue);
    color: var(--white);
}

.btn-primary:hover {
    background: #2D5F8D;
    transform: translateY(-2px);
    box-shadow: 0 4px 12px rgba(55, 118, 171, 0.3);
}

.btn-secondary {
    background: transparent;
    color: var(--python-blue);
    border: 2px solid var(--python-blue);
}

.btn-secondary:hover {
    background: var(--python-blue);
    color: var(--white);
    transform: translateY(-2px);
}

/* ===========================
   Navigation
   =========================== */

.nav {
    padding: var(--spacing-md) 0;
    border-bottom: 1px solid #E5E7EB;
}

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

.nav-brand .logo {
    font-size: 1.75rem;
    font-weight: 800;
    color: var(--python-blue);
    letter-spacing: -0.02em;
}

.nav-links {
    display: flex;
    gap: var(--spacing-md);
    align-items: center;
}

.nav-links a {
    font-weight: 500;
    padding: 0.5rem 1rem;
    border-radius: 4px;
    transition: background var(--transition-fast);
}

.nav-links a:not(.btn-primary):hover {
    background: var(--light-gray);
}

/* ===========================
   Hero Section
   =========================== */

.hero {
    background: linear-gradient(135deg, #F8F9FA 0%, #FFFFFF 100%);
    min-height: 90vh;
    display: flex;
    flex-direction: column;
}

.hero-content {
    flex: 1;
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    text-align: center;
    padding: var(--spacing-xl) var(--spacing-md);
}

.hero-title {
    margin-bottom: var(--spacing-md);
    background: linear-gradient(135deg, var(--python-blue) 0%, var(--dark-gray) 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    font-weight: 900;
    letter-spacing: -0.03em;
}

.hero-subtitle {
    font-size: clamp(1.125rem, 3vw, 1.5rem);
    color: var(--developer-gray);
    margin-bottom: var(--spacing-lg);
    max-width: 600px;
}

.hero-cta {
    display: flex;
    gap: var(--spacing-md);
    margin-bottom: var(--spacing-lg);
    flex-wrap: wrap;
    justify-content: center;
}

.hero-code {
    max-width: 600px;
    width: 100%;
    margin-top: var(--spacing-md);
}

.hero-code pre {
    text-align: left;
    background: var(--dark-gray);
    border: 1px solid #E5E7EB;
    box-shadow: 0 10px 40px rgba(0, 0, 0, 0.1);
}

/* ===========================
   Why ZVC Section
   =========================== */

.why-zvc {
    background: var(--white);
}

.features-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: var(--spacing-lg);
}

.feature-card {
    text-align: center;
    padding: var(--spacing-lg);
    border-radius: 12px;
    background: var(--light-gray);
    transition: transform var(--transition-base), box-shadow var(--transition-base);
}

.feature-card:hover {
    transform: translateY(-8px);
    box-shadow: 0 12px 32px rgba(0, 0, 0, 0.1);
}

.feature-icon {
    font-size: 4rem;
    margin-bottom: var(--spacing-md);
}

.feature-card h3 {
    margin-bottom: var(--spacing-sm);
    color: var(--python-blue);
}

.feature-card p {
    color: var(--developer-gray);
    margin-bottom: 0;
}

/* ===========================
   Quick Start Section
   =========================== */

.quick-start {
    background: var(--light-gray);
}

.quick-start-content {
    display: grid;
    grid-template-columns: 1fr;
    gap: var(--spacing-lg);
    margin-bottom: var(--spacing-lg);
    max-width: 800px;
    margin-left: auto;
    margin-right: auto;
}

.quick-start-step {
    background: var(--white);
    padding: var(--spacing-lg);
    border-radius: 12px;
    position: relative;
    border: 2px solid #E5E7EB;
}

.step-number {
    position: absolute;
    top: -1rem;
    left: var(--spacing-md);
    background: var(--python-blue);
    color: var(--white);
    width: 2.5rem;
    height: 2.5rem;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-weight: 700;
    font-size: 1.25rem;
}

.quick-start-step h3 {
    margin-top: var(--spacing-sm);
    margin-bottom: var(--spacing-md);
}

.quick-start-step pre {
    margin-bottom: 0;
}

.quick-start-footer {
    text-align: center;
    padding: var(--spacing-md);
}

.quick-start-footer p {
    font-size: 1.125rem;
    color: var(--developer-gray);
    margin-bottom: var(--spacing-sm);
}

.link-arrow {
    font-weight: 600;
    font-size: 1.125rem;
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    transition: gap var(--transition-base);
}

.link-arrow:hover {
    gap: 1rem;
}

/* ===========================
   Use Cases Section
   =========================== */

.use-cases {
    background: var(--white);
}

.use-cases-grid {
    display: grid;
    grid-template-columns: 1fr;
    gap: var(--spacing-md);
    max-width: 800px;
    margin-left: auto;
    margin-right: auto;
}

.use-case {
    padding: var(--spacing-lg);
    border: 2px solid #E5E7EB;
    border-radius: 8px;
    transition: border-color var(--transition-base);
}

.use-case:hover {
    border-color: var(--python-blue);
}

.use-case h3 {
    margin-bottom: var(--spacing-sm);
    font-size: 1.25rem;
}

.use-case p {
    color: var(--developer-gray);
    margin-bottom: 0;
}

/* ===========================
   Footer
   =========================== */

.footer {
    background: var(--dark-gray);
    color: var(--light-gray);
    padding: var(--spacing-xl) 0 var(--spacing-md);
}

.footer-content {
    display: grid;
    grid-template-columns: 2fr 3fr;
    gap: var(--spacing-lg);
    margin-bottom: var(--spacing-lg);
    padding-bottom: var(--spacing-lg);
    border-bottom: 1px solid #404040;
}

.footer-brand .logo {
    font-size: 2rem;
    font-weight: 800;
    color: var(--python-yellow);
    margin-bottom: var(--spacing-sm);
}

.footer-brand p {
    color: #8B949E;
}

.footer-links {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: var(--spacing-md);
}

.footer-column h4 {
    color: var(--white);
    margin-bottom: var(--spacing-sm);
    font-size: 0.875rem;
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

.footer-column a {
    display: block;
    color: #8B949E;
    margin-bottom: var(--spacing-xs);
    font-size: 0.9rem;
}

.footer-column a:hover {
    color: var(--python-yellow);
}

.footer-bottom {
    display: flex;
    justify-content: space-between;
    align-items: center;
    flex-wrap: wrap;
    gap: var(--spacing-sm);
}

.footer-bottom p {
    color: #8B949E;
    font-size: 0.875rem;
    margin-bottom: 0;
}

.built-with {
    font-weight: 600;
}

/* ===========================
   Responsive Design
   =========================== */

@media (max-width: 768px) {
    .hero-cta {
        flex-direction: column;
        width: 100%;
    }

    .hero-cta .btn {
        width: 100%;
    }

    .nav-links {
        gap: var(--spacing-sm);
    }

    .nav-links a:not(.btn-primary) {
        display: none;
    }

    .footer-content {
        grid-template-columns: 1fr;
    }

    .footer-links {
        grid-template-columns: 1fr;
    }

    .footer-bottom {
        flex-direction: column;
        text-align: center;
    }

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

@media (max-width: 480px) {
    :root {
        --spacing-xl: 3rem;
        --spacing-lg: 2rem;
    }

    .nav-brand .logo {
        font-size: 1.5rem;
    }

    .hero-title {
        font-size: 2.5rem;
    }

    section {
        padding: var(--spacing-lg) 0;
    }
}

/* ===========================
   Accessibility
   =========================== */

@media (prefers-reduced-motion: reduce) {
    * {
        animation-duration: 0.01ms !important;
        animation-iteration-count: 1 !important;
        transition-duration: 0.01ms !important;
        scroll-behavior: auto !important;
    }
}

/* Focus styles for keyboard navigation */
a:focus,
button:focus {
    outline: 2px solid var(--python-blue);
    outline-offset: 2px;
}

/* Print styles */
@media print {
    .nav,
    .hero-cta,
    .footer {
        display: none;
    }
}