:root {
    --accent: #ef4444;
    --accent-dark: #dc2626;
    --accent-light: #fee2e2;
    --accent-subtle: #fef2f2;
    --background: #ffffff;
    --card-bg: #fafafa;
    --surface: #f5f5f5;
    --text-primary: #000000;
    --text-secondary: #525252;
    --text-tertiary: #737373;
    --text-muted: #a3a3a3;
    --border: #d4d4d4;
    --border-light: #e5e5e5;
    --shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -1px rgba(0, 0, 0, 0.06);
    --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
}

* {
    box-sizing: border-box;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

html {
    scroll-behavior: smooth;
}

body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, sans-serif;
    margin: 0;
    background: var(--background);
    color: var(--text-primary);
    line-height: 1.5;
}

.container {
    max-width: 1080px;
    margin: 0 auto;
    padding: 0 24px;
}

/* Header */
.header {
    background: rgba(255, 255, 255, 0.8);
    backdrop-filter: blur(8px);
    border-bottom: 1px solid var(--border-light);
    position: sticky;
    top: 0;
    z-index: 100;
}

.header-inner {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 16px 0;
}

.brand {
    display: flex;
    align-items: center;
    gap: 12px;
    text-decoration: none;
    color: inherit;
}

.icon {
    width: 44px;
    height: 44px;
    border-radius: 10px;
    box-shadow: var(--shadow-sm);
}

.brand-title {
    margin: 0;
    font-size: 18px;
    font-weight: 800;
    letter-spacing: -0.025em;
}

.brand-subtitle {
    margin: 0;
    font-size: 12px;
    color: var(--text-tertiary);
    font-weight: 500;
}

.nav {
    display: flex;
    gap: 28px;
}

.nav a {
    text-decoration: none;
    font-size: 14px;
    color: var(--text-secondary);
    font-weight: 500;
    transition: color 0.2s;
}

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

/* Hero Section */
.hero {
    display: grid;
    grid-template-columns: 1.2fr 0.8fr;
    gap: 64px;
    align-items: center;
    padding: 80px 0;
}

.badge {
    display: inline-block;
    padding: 6px 12px;
    background: var(--accent-subtle);
    color: var(--accent-dark);
    border-radius: 999px;
    font-size: 12px;
    font-weight: 600;
    margin-bottom: 16px;
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

.hero h1 {
    margin: 0 0 20px;
    font-size: 56px;
    font-weight: 800;
    line-height: 1.1;
    letter-spacing: -0.04em;
}

.hero-subtitle {
    margin: 0 0 40px;
    font-size: 18px;
    color: var(--text-secondary);
    max-width: 480px;
}

/* Buttons */
.actions {
    display: flex;
    gap: 16px;
}

.actions.center {
    justify-content: center;
}

.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 10px;
    padding: 14px 28px;
    border-radius: 12px;
    text-decoration: none;
    font-weight: 600;
    font-size: 15px;
    transition: all 0.2s cubic-bezier(0.4, 0, 0.2, 1);
    cursor: pointer;
}

.btn.store {
    background: var(--text-primary);
    color: white;
}

.btn.store:hover {
    transform: translateY(-2px);
    box-shadow: 0 10px 15px -3px rgba(0, 0, 0, 0.1);
}

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

.btn.primary:hover {
    background: var(--accent-dark);
}

.store-svg {
    fill: currentColor;
}

/* Hero Visual & Word Card */
.hero-visual {
    position: relative;
    perspective: 1000px;
}

.card-stack {
    position: relative;
    width: 100%;
    max-width: 340px;
    margin: 0 auto;
}

.word-card {
    background: var(--background);
    border: 1px solid var(--border-light);
    border-radius: 24px;
    padding: 32px;
    box-shadow: 0 20px 25px -5px rgba(0, 0, 0, 0.05);
    position: relative;
    z-index: 2;
    transition: transform 0.3s ease;
}

.word-card:hover {
    transform: translateY(-5px);
}

.decoration-card {
    position: absolute;
    width: 100%;
    height: 100%;
    background: var(--card-bg);
    border: 1px solid var(--border-light);
    border-radius: 24px;
    z-index: 1;
}

.card-1 {
    top: 15px;
    right: -15px;
    transform: rotate(3deg);
    opacity: 0.6;
}

.card-2 {
    top: 30px;
    right: -30px;
    transform: rotate(6deg);
    opacity: 0.3;
}

.word-header {
    display: flex;
    align-items: baseline;
    justify-content: space-between;
    margin-bottom: 4px;
}

.word {
    font-size: 32px;
    font-weight: 800;
    letter-spacing: -0.02em;
}

.pill {
    font-size: 12px;
    font-weight: 700;
    color: var(--text-tertiary);
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

.transcription {
    font-size: 14px;
    color: var(--text-tertiary);
    font-family: monospace;
    margin: 0 0 16px;
}

.definition {
    font-size: 16px;
    color: var(--text-primary);
    margin: 0 0 16px;
    font-weight: 500;
}

.example {
    font-size: 15px;
    color: var(--text-secondary);
    font-style: italic;
    margin: 0 0 32px;
    padding-left: 12px;
    border-left: 2px solid var(--border-light);
}

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

.streak {
    display: flex;
    align-items: center;
    gap: 8px;
    font-size: 14px;
    font-weight: 600;
    color: var(--text-secondary);
}

.mark-btn {
    padding: 8px 16px;
    background: var(--text-primary);
    color: white;
    border: none;
    border-radius: 8px;
    font-size: 13px;
    font-weight: 600;
    opacity: 0.5;
}

/* How it Works */
.how-it-works {
    background: var(--card-bg);
    padding: 100px 0;
}

.section-header {
    text-align: center;
    max-width: 600px;
    margin: 0 auto 64px;
}

.section-header h2 {
    font-size: 36px;
    font-weight: 800;
    margin-bottom: 16px;
    letter-spacing: -0.03em;
}

.section-header p {
    color: var(--text-secondary);
    font-size: 18px;
}

.steps {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 40px;
}

.step {
    padding: 32px;
    background: var(--background);
    border-radius: 24px;
    border: 1px solid var(--border-light);
}

.step-num {
    font-size: 14px;
    font-weight: 800;
    color: var(--accent);
    margin-bottom: 12px;
}

.step h3 {
    font-size: 20px;
    font-weight: 700;
    margin: 0 0 12px;
}

.step p {
    color: var(--text-secondary);
    margin: 0;
    font-size: 15px;
}

/* Features Grid */
.features-grid {
    padding: 100px 0;
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 32px;
}

.feature-item {
    padding: 24px;
}

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

.feature-item h3 {
    font-size: 18px;
    font-weight: 700;
    margin: 0 0 10px;
}

.feature-item p {
    color: var(--text-secondary);
    font-size: 15px;
    margin: 0;
}

/* CTA */
.cta {
    padding: 40px 0 100px;
}

.cta-box {
    background: var(--text-primary);
    color: white;
    border-radius: 32px;
    padding: 64px;
    text-align: center;
}

.cta-box h2 {
    font-size: 40px;
    font-weight: 800;
    margin-bottom: 16px;
    letter-spacing: -0.03em;
}

.cta-box p {
    color: var(--text-muted);
    font-size: 18px;
    margin-bottom: 40px;
}

/* Support */
.support {
    padding: 100px 0;
    border-top: 1px solid var(--border-light);
}

.support-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 80px;
}

.support h2 {
    font-size: 32px;
    font-weight: 800;
    margin-bottom: 16px;
}

.email-link {
    font-size: 20px;
    font-weight: 600;
    color: var(--accent);
    text-decoration: none;
}

.support-links h3 {
    font-size: 14px;
    text-transform: uppercase;
    letter-spacing: 0.1em;
    color: var(--text-tertiary);
    margin-bottom: 24px;
}

.support-links a {
    display: block;
    margin-bottom: 12px;
    color: var(--text-secondary);
    text-decoration: none;
    font-weight: 500;
}

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

/* Footer */
.footer {
    padding: 48px 0;
    border-top: 1px solid var(--border-light);
}

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

.footer-title {
    font-weight: 800;
    font-size: 16px;
    margin: 0 0 4px;
}

.footer p {
    color: var(--text-muted);
    font-size: 14px;
    margin: 0;
}

/* Mobile Responsive */
@media (max-width: 960px) {
    .hero {
        grid-template-columns: 1fr;
        padding: 40px 0;
        text-align: center;
    }

    .hero h1 {
        font-size: 44px;
    }

    .hero-subtitle {
        margin: 0 auto 40px;
    }

    .actions {
        justify-content: center;
    }

    .hero-visual {
        margin-top: 40px;
        max-width: 100%;
    }

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

    .support-grid {
        grid-template-columns: 1fr;
        gap: 48px;
    }
}

@media (max-width: 600px) {
    .nav {
        display: none;
    }

    .cta-box {
        padding: 40px 24px;
    }

    .cta-box h2 {
        font-size: 28px;
    }

    .actions {
        flex-direction: column;
    }
}