/* CSS Variables */
:root {
    --color-primary: #3B82F6;
    --color-primary-dark: #2563EB;
    --color-accent: #8B5CF6;
    --color-text: #1F2937;
    --color-text-light: #6B7280;
    --color-background: #FFFFFF;
    --color-surface: #F9FAFB;
    --color-border: #E5E7EB;
    --gradient-primary: linear-gradient(135deg, #3B82F6 0%, #8B5CF6 100%);
    --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
    --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -1px rgba(0, 0, 0, 0.06);
    --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1), 0 4px 6px -2px rgba(0, 0, 0, 0.05);
    --shadow-xl: 0 20px 25px -5px rgba(0, 0, 0, 0.1), 0 10px 10px -5px rgba(0, 0, 0, 0.04);
    --shadow-2xl: 0 0 50px rgba(0, 0, 0, 0.3), 0 0 20px rgba(0, 0, 0, 0.15);
    --radius-sm: 6px;
    --radius-md: 12px;
    --radius-lg: 16px;
    --radius-xl: 24px;
}

/* Reset & Base */
*, *::before, *::after {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

html {
    scroll-behavior: smooth;
}

body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    color: var(--color-text);
    background: var(--color-background);
    line-height: 1.6;
    -webkit-font-smoothing: antialiased;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 24px;
}

/* Navigation */
.nav {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 20px 48px;
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    z-index: 100;
}

.nav-brand {
    display: flex;
    align-items: center;
    gap: 12px;
    font-weight: 600;
    font-size: 1.25rem;
    color: var(--color-text);
}

.nav-brand .logo,
.footer-brand .logo {
    border-radius: var(--radius-md);
}

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

.nav-links a:not(.btn) {
    color: var(--color-text-light);
    text-decoration: none;
    font-weight: 500;
    font-size: 0.95rem;
    transition: color 0.2s;
}

.nav-links a:not(.btn):hover {
    color: var(--color-text);
}

/* Buttons */
.btn {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    padding: 12px 24px;
    border-radius: var(--radius-md);
    font-weight: 600;
    font-size: 1rem;
    text-decoration: none;
    transition: all 0.2s;
    cursor: pointer;
    border: none;
}

.btn-primary {
    background: var(--gradient-primary);
    color: white;
    box-shadow: var(--shadow-md), 0 0 0 0 rgba(59, 130, 246, 0.5);
}

.btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-lg), 0 0 20px rgba(59, 130, 246, 0.3);
}

.btn-small {
    padding: 8px 16px;
    font-size: 0.875rem;
    background: var(--color-primary);
    color: white;
    border-radius: var(--radius-sm);
}

.btn-small:hover {
    background: var(--color-primary-dark);
    color: white;
}

.btn-large {
    padding: 16px 32px;
    font-size: 1.125rem;
}

/* Hero Section */
.hero {
    background: linear-gradient(180deg, #F8FAFC 0%, #FFFFFF 100%);
    padding: 140px 48px 80px;
    text-align: center;
    position: relative;
    overflow: hidden;
}

.hero::before {
    content: '';
    position: absolute;
    top: 0;
    left: 50%;
    transform: translateX(-50%);
    width: 100%;
    max-width: 1000px;
    height: 600px;
    background: radial-gradient(ellipse at center, rgba(59, 130, 246, 0.08) 0%, transparent 70%);
    pointer-events: none;
}

.hero-content {
    position: relative;
    z-index: 1;
    max-width: 800px;
    margin: 0 auto;
}

.hero h1 {
    font-size: clamp(2.5rem, 5vw, 4rem);
    font-weight: 700;
    line-height: 1.1;
    margin-bottom: 24px;
    background: var(--gradient-primary);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.hero-subtitle {
    font-size: 1.25rem;
    color: var(--color-text-light);
    max-width: 600px;
    margin: 0 auto 32px;
    line-height: 1.7;
}

.hero-cta {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 12px;
}

.hero-badge {
    font-size: 0.875rem;
    color: var(--color-text-light);
}

.hero-image {
    margin-top: 60px;
    position: relative;
    z-index: 1;
}

.hero-image img {
    max-width: 900px;
    width: 100%;
    border-radius: var(--radius-xl);
    box-shadow: var(--shadow-2xl), 0 0 0 1px rgba(0, 0, 0, 0.05);
}

/* Problem Section */
.problem {
    padding: 100px 0;
    background: var(--color-surface);
}

.problem-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 80px;
    align-items: center;
}

.section-label {
    display: inline-block;
    font-size: 0.875rem;
    font-weight: 600;
    color: var(--color-primary);
    text-transform: uppercase;
    letter-spacing: 0.05em;
    margin-bottom: 16px;
}

.problem-content h2 {
    font-size: 2.25rem;
    font-weight: 700;
    line-height: 1.2;
    margin-bottom: 20px;
}

.problem-content p {
    font-size: 1.125rem;
    color: var(--color-text-light);
    line-height: 1.7;
}

.problem-stats {
    display: flex;
    flex-direction: column;
    gap: 40px;
}

.stat {
    display: flex;
    flex-direction: column;
    gap: 8px;
}

.stat-number {
    font-size: 4rem;
    font-weight: 700;
    background: var(--gradient-primary);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    line-height: 1;
}

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

/* Features Section */
.features {
    padding: 100px 0;
}

.features h2 {
    font-size: 2.5rem;
    font-weight: 700;
    margin-bottom: 60px;
    max-width: 500px;
}

.feature-cards {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 32px;
}

.feature-card {
    padding: 32px;
    background: var(--color-surface);
    border-radius: var(--radius-lg);
    border: 1px solid var(--color-border);
    transition: all 0.3s;
}

.feature-card:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-lg);
    border-color: transparent;
}

.feature-icon {
    width: 48px;
    height: 48px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: var(--gradient-primary);
    border-radius: var(--radius-md);
    color: white;
    margin-bottom: 20px;
}

.feature-card h3 {
    font-size: 1.25rem;
    font-weight: 600;
    margin-bottom: 12px;
}

.feature-card p {
    color: var(--color-text-light);
    font-size: 0.95rem;
    line-height: 1.6;
}

/* How It Works Section */
.how-it-works {
    padding: 100px 0;
    background: var(--color-surface);
}

.how-it-works h2 {
    font-size: 2.5rem;
    font-weight: 700;
    margin-bottom: 80px;
}

.step {
    display: grid;
    grid-template-columns: 1fr 1.2fr;
    gap: 80px;
    align-items: center;
    margin-bottom: 100px;
}

.step:last-child {
    margin-bottom: 0;
}

.step-reverse {
    direction: rtl;
}

.step-reverse > * {
    direction: ltr;
}

.step-number {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    width: 40px;
    height: 40px;
    background: var(--gradient-primary);
    color: white;
    font-weight: 700;
    font-size: 1.25rem;
    border-radius: 50%;
    margin-bottom: 20px;
}

.step-content h3 {
    font-size: 1.75rem;
    font-weight: 700;
    margin-bottom: 16px;
}

.step-content > p {
    font-size: 1.125rem;
    color: var(--color-text-light);
    line-height: 1.7;
    margin-bottom: 24px;
}

.step-features {
    list-style: none;
    display: flex;
    flex-direction: column;
    gap: 12px;
}

.step-features li {
    display: flex;
    align-items: center;
    gap: 12px;
    color: var(--color-text-light);
}

.step-features li::before {
    content: '';
    width: 20px;
    height: 20px;
    background: var(--color-primary);
    mask: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 24 24' fill='none' stroke='currentColor' stroke-width='3'%3E%3Cpath d='M20 6L9 17l-5-5'/%3E%3C/svg%3E") center/contain no-repeat;
    -webkit-mask: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 24 24' fill='none' stroke='currentColor' stroke-width='3'%3E%3Cpath d='M20 6L9 17l-5-5'/%3E%3C/svg%3E") center/contain no-repeat;
    flex-shrink: 0;
}

.step-image img {
    width: 100%;
    border-radius: var(--radius-xl);
    box-shadow: var(--shadow-2xl);
}

/* Fullscreen Feature Section */
.fullscreen-feature {
    padding: 100px 0;
    background: linear-gradient(180deg, #1F2937 0%, #111827 100%);
    color: white;
}

.fullscreen-feature .container {
    display: grid;
    grid-template-columns: 1fr 1.5fr;
    gap: 60px;
    align-items: center;
}

.fullscreen-feature .section-label {
    color: var(--color-accent);
}

.fullscreen-content h2 {
    font-size: 2.25rem;
    font-weight: 700;
    margin-bottom: 20px;
}

.fullscreen-content > p {
    font-size: 1.125rem;
    color: #9CA3AF;
    line-height: 1.7;
    margin-bottom: 32px;
}

.keyboard-hints {
    display: flex;
    flex-direction: column;
    gap: 16px;
}

.key-hint {
    display: flex;
    align-items: center;
    gap: 12px;
}

kbd {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    min-width: 32px;
    height: 32px;
    padding: 0 10px;
    background: rgba(255, 255, 255, 0.1);
    border: 1px solid rgba(255, 255, 255, 0.2);
    border-radius: 6px;
    font-family: inherit;
    font-size: 0.875rem;
    font-weight: 500;
    color: white;
}

.key-hint span {
    color: #9CA3AF;
    font-size: 0.95rem;
}

.fullscreen-image img {
    width: 100%;
    border-radius: var(--radius-xl);
    box-shadow: 0 0 60px rgba(0, 0, 0, 0.5), 0 0 25px rgba(0, 0, 0, 0.3);
}

/* Download Section */
.download {
    padding: 120px 0;
    text-align: center;
    background: linear-gradient(180deg, #FFFFFF 0%, #F8FAFC 100%);
}

.download-content {
    max-width: 600px;
    margin: 0 auto;
}

.download h2 {
    font-size: 2.5rem;
    font-weight: 700;
    margin-bottom: 16px;
}

.download > .download-content > p:first-of-type {
    font-size: 1.25rem;
    color: var(--color-text-light);
    margin-bottom: 2em;
}

.download-requirements {
    margin-top: 16px;
    font-size: 0.875rem;
    color: var(--color-text-light);
}

/* Footer */
.footer {
    padding: 40px 0;
    border-top: 1px solid var(--color-border);
}

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

.footer-brand {
    display: flex;
    align-items: center;
    gap: 8px;
    font-weight: 600;
}

.footer-copyright {
    font-size: 0.875rem;
    color: var(--color-text-light);
}

.footer-links {
    display: flex;
    align-items: center;
    gap: 24px;
}

.footer-links a {
    font-size: 0.875rem;
    color: var(--color-text-light);
    text-decoration: none;
}

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

/* Privacy Page */
.privacy-page {
    padding: 120px 24px 80px;
    max-width: 800px;
    margin: 0 auto;
}

.privacy-page h1 {
    font-size: 2.5rem;
    font-weight: 700;
    margin-bottom: 8px;
}

.privacy-page .last-updated {
    color: var(--color-text-light);
    margin-bottom: 48px;
}

.privacy-page section {
    margin-bottom: 40px;
}

.privacy-page h2 {
    font-size: 1.5rem;
    font-weight: 600;
    margin-bottom: 16px;
}

.privacy-page p {
    color: var(--color-text-light);
    line-height: 1.7;
    margin-bottom: 16px;
}

.privacy-page ul {
    list-style: none;
    padding: 0;
    margin: 0 0 16px 0;
}

.privacy-page li {
    color: var(--color-text-light);
    line-height: 1.7;
    padding-left: 24px;
    position: relative;
    margin-bottom: 8px;
}

.privacy-page li::before {
    content: '•';
    position: absolute;
    left: 8px;
    color: var(--color-primary);
}

.privacy-page a {
    color: var(--color-primary);
}

.privacy-page a:hover {
    text-decoration: none;
}

/* Lightbox */
.lightbox {
    display: none;
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(0, 0, 0, 0.9);
    z-index: 1000;
    cursor: zoom-out;
    align-items: center;
    justify-content: center;
}

.lightbox.active {
    display: flex;
}

.lightbox img {
    max-width: 90%;
    max-height: 90%;
    border-radius: var(--radius-lg);
    box-shadow: 0 0 60px rgba(0, 0, 0, 0.5);
}

.lightbox-trigger {
    cursor: zoom-in;
}

.lightbox-nav {
    position: absolute;
    top: 50%;
    transform: translateY(-50%);
    background: rgba(255, 255, 255, 0.1);
    border: 1px solid rgba(255, 255, 255, 0.2);
    border-radius: 50%;
    width: 48px;
    height: 48px;
    display: flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    color: white;
    transition: all 0.2s;
}

.lightbox-nav:hover {
    background: rgba(255, 255, 255, 0.2);
}

.lightbox-prev {
    left: 24px;
}

.lightbox-next {
    right: 24px;
}

/* Responsive Design */
@media (max-width: 1024px) {
    .feature-cards {
        grid-template-columns: repeat(2, 1fr);
    }

    .step,
    .step-reverse {
        grid-template-columns: 1fr;
        gap: 40px;
    }

    .step-reverse {
        direction: ltr;
    }

    .fullscreen-feature .container {
        grid-template-columns: 1fr;
        gap: 40px;
    }

    .problem-grid {
        grid-template-columns: 1fr;
        gap: 40px;
    }
}

@media (max-width: 768px) {
    .nav {
        padding: 16px 24px;
    }

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

    .hero {
        padding: 120px 24px 60px;
    }

    .hero h1 {
        font-size: 2.25rem;
    }

    .hero-subtitle {
        font-size: 1.1rem;
    }

    .feature-cards {
        grid-template-columns: 1fr;
    }

    .stat-number {
        font-size: 3rem;
    }

    .step-content h3 {
        font-size: 1.5rem;
    }

    .fullscreen-content h2,
    .download h2,
    .features h2,
    .how-it-works h2,
    .problem-content h2 {
        font-size: 1.75rem;
    }

    .footer-content {
        flex-direction: column;
        gap: 16px;
        text-align: center;
    }

    .keyboard-hints {
        flex-wrap: wrap;
        flex-direction: row;
        gap: 24px;
    }
}