:root {
    --color-bg: #ffffff;
    --color-text: #0f172a;
    --color-text-muted: #64748b;
    --color-primary: #0ea5e9; /* Sky 500 */
    --color-primary-hover: #0284c7; /* Sky 600 */
    --color-secondary: #6366f1; /* Indigo 500 */
    --color-accent: #f472b6;
    --color-surface: #f8fafc; /* Slate 50 */
    --color-surface-hover: #f1f5f9; /* Slate 100 */
    
    --font-sans: 'Inter', 'Noto Sans JP', sans-serif;
    
    --spacing-xs: 0.5rem;
    --spacing-sm: 1rem;
    --spacing-md: 2rem;
    --spacing-lg: 4rem;
    --spacing-xl: 8rem;
    
    --border-radius-sm: 0.5rem;
    --border-radius-md: 1rem;
    --border-radius-lg: 2rem;
    
    --container-width: 1200px;
    --header-height: 80px;
}

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

body {
    font-family: var(--font-sans);
    background-color: var(--color-bg);
    color: var(--color-text);
    line-height: 1.6;
    -webkit-font-smoothing: antialiased;
    overflow-x: hidden; /* Prevent horizontal scroll */
}

a {
    text-decoration: none;
    color: inherit;
    transition: color 0.3s ease;
}

ul {
    list-style: none;
}

img {
    max-width: 100%;
    height: auto;
    display: block;
}

.container {
    width: 90%;
    max-width: var(--container-width);
    margin: 0 auto;
    padding: 0 var(--spacing-sm);
    position: relative;
    z-index: 1; /* Ensure content is above background */
}

.btn {
    display: inline-block;
    padding: 0.75rem 1.5rem;
    border-radius: var(--border-radius-md);
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s ease;
    border: none;
}

.btn-primary {
    background: linear-gradient(135deg, var(--color-primary), var(--color-secondary));
    color: #fff;
    box-shadow: 0 4px 15px -3px rgba(99, 102, 241, 0.4);
    border: 1px solid rgba(255, 255, 255, 0.1);
}

.btn-primary:hover {
    opacity: 0.9;
    transform: translateY(-2px);
    box-shadow: 0 10px 20px -3px rgba(99, 102, 241, 0.5);
}

.btn-store {
    background-color: #fff;
    color: var(--color-text);
    border: 1px solid #e2e8f0;
    box-shadow: 0 1px 3px 0 rgba(0, 0, 0, 0.1);
}

.btn-store:hover {
    background-color: var(--color-surface-hover);
    border-color: var(--color-primary);
    transform: translateY(-2px);
}

/* Header */
.site-header {
    height: var(--header-height);
    display: flex;
    align-items: center;
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    background-color: rgba(255, 255, 255, 0.8);
    backdrop-filter: blur(10px);
    z-index: 1000;
    border-bottom: 1px solid rgba(0, 0, 0, 0.05);
}

.site-header .btn-primary {
    background: linear-gradient(135deg, var(--color-primary-hover), var(--color-secondary));
}

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

.logo {
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--color-primary);
}

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

.main-nav ul {
    display: flex;
    gap: var(--spacing-md);
    margin-right: var(--spacing-md);
}

.main-nav ul a {
    font-weight: 500;
    color: var(--color-text-muted);
}

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

.mobile-menu-toggle {
    display: none;
    background: none;
    border: none;
    cursor: pointer;
    flex-direction: column;
    gap: 6px;
}

.mobile-menu-toggle span {
    display: block;
    width: 24px;
    height: 2px;
    background-color: var(--color-text);
    transition: 0.3s;
}

/* Hero */
.hero {
    padding-top: calc(var(--header-height) + var(--spacing-xl));
    padding-bottom: var(--spacing-xl);
    position: relative;
    overflow: hidden;
}

/* Three.js Canvas Container */
#canvas-container {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    z-index: 0;
    pointer-events: none; /* Allow clicks to pass through */
}

.hero .container {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: var(--spacing-lg);
    align-items: center;
}

.hero-content h1 {
    font-size: 3.5rem;
    line-height: 1.2;
    margin-bottom: var(--spacing-md);
    color: var(--color-text);
    font-weight: 800;
    letter-spacing: -0.02em;
}

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

.cta-group {
    display: flex;
    gap: var(--spacing-sm);
    flex-wrap: wrap;
}

.hero-visual {
    position: relative;
    perspective: 1000px;
}

.phone-mockup {
    border-radius: 40px;
    box-shadow: 0 25px 50px -12px rgba(0, 0, 0, 0.25);
    border: 8px solid #1e293b;
    transition: transform 0.5s ease;
    background-color: #fff;
}

.hero-visual:hover .phone-mockup {
    transform: translateY(-10px) rotateY(-5deg);
}

/* Video Ad Section */
.video-ad-section {
    padding: var(--spacing-xl) 0;
    background-color: var(--color-bg);
}

.video-wrapper {
    max-width: 900px;
    margin: 0 auto;
    border-radius: var(--border-radius-lg);
    overflow: hidden;
    box-shadow: 0 20px 25px -5px rgba(0, 0, 0, 0.1), 0 10px 10px -5px rgba(0, 0, 0, 0.04);
    background-color: #000;
}

.video-wrapper video {
    width: 100%;
    height: auto;
    display: block;
}

/* Problem & Solution */
.problem-solution {
    padding: var(--spacing-xl) 0;
    background-color: var(--color-surface);
}

.text-center {
    text-align: center;
    max-width: 800px;
    margin: 0 auto;
}

.problem-solution h2 {
    font-size: 2.5rem;
    margin-bottom: var(--spacing-md);
    color: var(--color-text);
}

.solution-text {
    font-size: 1.5rem;
    color: var(--color-primary);
    font-weight: 700;
}

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

.feature-item {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: var(--spacing-xl);
    align-items: center;
    margin-bottom: var(--spacing-xl);
}

.feature-item.reverse {
    direction: rtl;
}

.feature-item.reverse .feature-text {
    direction: ltr;
}

.feature-text h3 {
    font-size: 2rem;
    margin-bottom: var(--spacing-sm);
    color: var(--color-text);
}

.feature-text p {
    font-size: 1.1rem;
    color: var(--color-text-muted);
}

.phone-mockup.small {
    max-width: 300px;
    margin: 0 auto;
    box-shadow: 0 20px 25px -5px rgba(0, 0, 0, 0.1), 0 10px 10px -5px rgba(0, 0, 0, 0.04);
}

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

.section-title {
    text-align: center;
    font-size: 2.5rem;
    margin-bottom: var(--spacing-lg);
    color: var(--color-text);
}

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

.step-card {
    background-color: var(--color-bg);
    padding: var(--spacing-md);
    border-radius: var(--border-radius-md);
    text-align: center;
    border: 1px solid #e2e8f0;
    transition: transform 0.3s ease, box-shadow 0.3s ease;
}

.step-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 10px 15px -3px rgba(0, 0, 0, 0.1);
    border-color: var(--color-primary);
}

.step-image {
    margin-bottom: var(--spacing-sm);
    display: flex;
    justify-content: center;
    align-items: center;
    height: 180px; /* Fixed height for consistency */
}

.step-image img {
    max-height: 100%;
    width: auto;
    object-fit: contain;
    transition: transform 0.3s ease;
}

.step-card:hover .step-image img {
    transform: scale(1.05);
}

.step-number {
    font-size: 3rem;
    font-weight: 900;
    color: #e2e8f0;
    margin-bottom: var(--spacing-sm);
}

.step-card h3 {
    margin-bottom: var(--spacing-sm);
    color: var(--color-text);
}

.step-card p {
    color: var(--color-text-muted);
    font-size: 0.9rem;
}

/* Testimonials */
.testimonials {
    padding: var(--spacing-xl) 0;
    background-color: var(--color-bg);
}

.testimonials-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: var(--spacing-md);
}

.testimonial-card {
    background-color: var(--color-surface);
    padding: var(--spacing-md);
    border-radius: var(--border-radius-md);
    border: 1px solid #e2e8f0;
}

.quote {
    font-size: 1.1rem;
    font-style: italic;
    margin-bottom: var(--spacing-md);
    color: var(--color-text);
}

.testimonial-author {
    display: flex;
    align-items: center;
    justify-content: flex-end;
    gap: var(--spacing-sm);
}

.avatar {
    width: 48px;
    height: 48px;
    border-radius: 50%;
    object-fit: cover;
    border: 2px solid var(--color-primary);
}

.author-name {
    color: var(--color-text-muted);
    font-size: 0.9rem;
    font-weight: 600;
}

/* Footer */
.site-footer {
    padding: var(--spacing-lg) 0;
    border-top: 1px solid #e2e8f0;
    text-align: center;
    background-color: var(--color-surface);
}

.footer-links {
    display: flex;
    justify-content: center;
    gap: var(--spacing-md);
    margin-bottom: var(--spacing-md);
}

.footer-links a {
    color: var(--color-text-muted);
    font-size: 0.9rem;
}

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

.copyright {
    color: var(--color-text-muted);
    font-size: 0.8rem;
}

/* Responsive */
@media (max-width: 768px) {
    .sm-hidden {
        display: none;
    }

    .mobile-menu-toggle {
        display: flex;
    }

    .main-nav {
        display: none; /* Implement JS toggle later */
    }
    
    .hero .container {
        grid-template-columns: 1fr;
        text-align: center;
    }
    
    .hero-content h1 {
        font-size: 2.5rem;
    }
    
    .cta-group {
        justify-content: center;
    }
    
    .feature-item {
        grid-template-columns: 1fr;
        text-align: center;
    }
    
    .feature-item.reverse {
        direction: ltr;
    }
    
    .feature-item.reverse .feature-text {
        direction: ltr;
    }
}

/* Animations */
.fade-in-section {
    opacity: 0;
    transform: translateY(20px);
    transition: opacity 0.6s ease-out, transform 0.6s ease-out;
    will-change: opacity, visibility;
}

.fade-in-section.visible {
    opacity: 1;
    transform: none;
}