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

:root {
    /* Monochrome colors */
    --bg-primary: #ffffff;
    --bg-secondary: #f8f9fa;
    --bg-tertiary: #e9ecef;
    --text-primary: #1a1a1a;
    --text-secondary: #666;
    --text-muted: #999;
    --border-color: #e9ecef;
    --shadow-color: rgba(0, 0, 0, 0.1);
    --accent-color: #1a1a1a;
    --accent-hover: #333;
}

body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    line-height: 1.6;
    color: var(--text-primary);
    background: var(--bg-primary);
    transition: background-color 0.3s ease, color 0.3s ease;
}

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

/* Navigation */
.navbar {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    background: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(10px);
    z-index: 1000;
    transition: all 0.3s ease;
    box-shadow: 0 2px 20px var(--shadow-color);
}

.navbar.scrolled {
    background: rgba(255, 255, 255, 0.98);
    box-shadow: 0 4px 30px var(--shadow-color);
}

.nav-container {
    max-width: 100%;
    margin: 0 auto;
    padding: 0 20px;
    display: flex;
    justify-content: space-between;
    align-items: center;
    height: 80px;
}

.nav-logo h2 {
    font-size: 1.8rem;
    font-weight: 700;
    color: var(--text-primary);
}

.nav-logo a {
    display: flex;
    align-items: center;
    gap: 20px;
}

.logo-img {
    height: 60px;
    width: auto;
    transition: opacity 0.3s ease;
}

.logo-img:hover {
    opacity: 0.8;
}

.logo-text {
    font-size: 2rem;
    font-weight: 700;
    color: var(--text-primary);
    transition: color 0.3s ease;
}

/* Logo - always show black version */
.logo-light {
    display: block;
}

.logo-dark {
    display: none;
}

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

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

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

/* Hero Section */
.hero {
    padding: 130px 0 80px;
    background: linear-gradient(135deg, var(--bg-secondary) 0%, var(--bg-tertiary) 100%);
    min-height: 100vh;
    display: flex;
    align-items: center;
}

.hero-container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 4rem;
    align-items: center;
}

.hero-content h1 {
    font-size: 3.5rem;
    font-weight: 700;
    color: var(--text-primary);
    margin-bottom: 1.5rem;
    line-height: 1.2;
}

.hero-subtitle {
    font-size: 1.3rem;
    color: var(--text-secondary);
    margin-bottom: 2.5rem;
    line-height: 1.6;
}

.hero-buttons {
    display: flex;
    gap: 1rem;
    flex-wrap: wrap;
}

.btn {
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    padding: 15px 30px;
    border-radius: 50px;
    text-decoration: none;
    font-weight: 600;
    font-size: 1.1rem;
    transition: all 0.3s ease;
    border: none;
    cursor: pointer;
}

.btn-primary {
    background: var(--accent-color);
    color: var(--bg-primary);
    box-shadow: 0 4px 15px var(--shadow-color);
}

.btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: 0 6px 20px var(--shadow-color);
    background: var(--accent-hover);
}

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

.btn-secondary:hover {
    background: var(--text-primary);
    color: var(--bg-primary);
}

.btn-large {
    padding: 18px 40px;
    font-size: 1.2rem;
}

.btn-icon {
    font-size: 1.2rem;
}

/* Phone Mockup */
.phone-mockup {
    width: 300px;
    height: 600px;
    background: #1a1a1a;
    border-radius: 40px;
    padding: 20px;
    margin: 0 auto;
    box-shadow: 0 20px 40px rgba(0, 0, 0, 0.3);
}

.phone-screen {
    width: 100%;
    height: 100%;
    background: white;
    border-radius: 30px;
    overflow: hidden;
    position: relative;
}

.app-preview {
    padding: 2rem 1.5rem;
    height: 100%;
    display: flex;
    flex-direction: column;
}

.app-header {
    text-align: center;
    margin-bottom: 2rem;
    padding-bottom: 1rem;
    border-bottom: 1px solid #eee;
}

.app-header h3 {
    font-size: 1.5rem;
    font-weight: 600;
    color: #333;
}

.habit-item, .todo-item {
    display: flex;
    align-items: center;
    gap: 1rem;
    padding: 1rem;
    margin-bottom: 0.5rem;
    background: #f8f9ff;
    border-radius: 12px;
    transition: all 0.3s ease;
}

.habit-item.completed {
    background: #e8f5e8;
    opacity: 0.8;
}

.habit-icon, .todo-icon {
    font-size: 1.5rem;
    width: 40px;
    text-align: center;
}

.habit-name, .todo-name {
    flex: 1;
    font-weight: 500;
    color: #333;
}

.habit-points, .todo-points {
    font-size: 0.9rem;
    font-weight: 600;
    color: #667eea;
}

/* Features Section */
.features {
    padding: 80px 0;
    background: var(--bg-primary);
}

.section-title {
    text-align: center;
    font-size: 2.5rem;
    font-weight: 700;
    margin-bottom: 3rem;
    color: var(--text-primary);
}

.features-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 3rem;
}

.feature-card {
    text-align: center;
    padding: 2rem;
    border-radius: 20px;
    background: var(--bg-secondary);
    transition: transform 0.3s ease;
    border: 1px solid var(--border-color);
}

.feature-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 10px 30px var(--shadow-color);
}

.feature-icon {
    width: 80px;
    height: 80px;
    background: var(--accent-color);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    margin: 0 auto 1.5rem;
    font-size: 2rem;
    color: var(--bg-primary);
}

.feature-card h3 {
    font-size: 1.5rem;
    font-weight: 600;
    margin-bottom: 1rem;
    color: var(--text-primary);
}

.feature-card p {
    color: var(--text-secondary);
    line-height: 1.6;
}

/* How It Works Section */
.how-it-works {
    padding: 80px 0;
    background: var(--bg-secondary);
    color: var(--text-primary);
}

.steps {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 3rem;
    margin-top: 3rem;
}

.step {
    text-align: center;
    padding: 2rem;
}

.step-number {
    width: 60px;
    height: 60px;
    background: var(--accent-color);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    margin: 0 auto 1.5rem;
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--bg-primary);
}

.step h3 {
    font-size: 1.5rem;
    font-weight: 600;
    margin-bottom: 1rem;
    color: var(--text-primary);
}

.step p {
    color: var(--text-secondary);
    line-height: 1.6;
}

/* Download Section */
.download {
    padding: 80px 0;
    background: var(--bg-primary);
    text-align: center;
}

.download-content h2 {
    font-size: 2.5rem;
    font-weight: 700;
    margin-bottom: 1.5rem;
    color: var(--text-primary);
}

.download-content p {
    font-size: 1.2rem;
    color: var(--text-secondary);
    margin-bottom: 3rem;
    max-width: 600px;
    margin-left: auto;
    margin-right: auto;
}

.download-buttons {
    margin-bottom: 2rem;
}

.download-note {
    font-size: 1rem;
    color: #999;
    font-style: italic;
}

/* Footer */
.footer {
    background: var(--bg-secondary);
    color: var(--text-primary);
    padding: 3rem 0 2rem;
    border-top: 1px solid var(--border-color);
}

.footer-content {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 2rem;
    margin-bottom: 2rem;
}

.footer-section h3, .footer-section h4 {
    font-size: 1.2rem;
    font-weight: 600;
    margin-bottom: 1rem;
    color: var(--text-primary);
}

.footer-logo {
    margin-bottom: 1rem;
}

.footer-logo-img {
    height: 32px;
    width: auto;
    opacity: 0.8;
    transition: opacity 0.3s ease;
}

.footer-logo-img:hover {
    opacity: 1;
}

.footer-section p,
.footer-section a {
    color: var(--text-secondary);
    text-decoration: none;
    line-height: 1.6;
}

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

.footer-section ul {
    list-style: none;
}

.footer-section li {
    margin-bottom: 0.5rem;
}

.footer-bottom {
    border-top: 1px solid #333;
    padding-top: 2rem;
    text-align: center;
    color: #999;
}

/* Responsive Design */
@media (max-width: 768px) {
    .hero-container {
        grid-template-columns: 1fr;
        gap: 2rem;
        text-align: center;
    }

    .hero-content h1 {
        font-size: 2.5rem;
    }

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

    .nav-links {
        gap: 1rem;
    }

    .phone-mockup {
        width: 250px;
        height: 500px;
    }

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

    .hero-buttons {
        justify-content: center;
    }
}

@media (max-width: 480px) {
    .hero-content h1 {
        font-size: 2rem;
    }

    .section-title {
        font-size: 2rem;
    }

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

    .phone-mockup {
        width: 200px;
        height: 400px;
    }

    .app-preview {
        padding: 1rem;
    }
}