:root {
    --primary-color: #FF6B6B;
    --secondary-color: #4CACFF;
    --accent-color: #4CD964;
    --text-primary: #333333;
    --text-secondary: #666666;
    --text-light: #FFFFFF;
    --background-light: #FFFFFF;
    --background-off: #F8F9FA;
    --border-radius: 16px;
    --shadow-sm: 0 4px 6px rgba(0, 0, 0, 0.04);
    --shadow-md: 0 8px 24px rgba(0, 0, 0, 0.06);
    --transition: all 0.3s ease;
}

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

html {
    scroll-behavior: smooth;
    font-size: 62.5%; /* 10px = 1rem */
}

body {
    font-family: 'Noto Sans JP', sans-serif;
    color: var(--text-primary);
    background-color: var(--background-light);
    line-height: 1.6;
    font-size: 1.6rem;
}

.container {
    width: 100%;
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 2rem;
}

/* Header Styles */
.header {
    background-color: var(--background-light);
    box-shadow: var(--shadow-sm);
    position: sticky;
    top: 0;
    z-index: 100;
    backdrop-filter: blur(10px);
    -webkit-backdrop-filter: blur(10px);
    background-color: rgba(255, 255, 255, 0.9);
}

.nav {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 1.5rem 0;
}

.logo {
    display: flex;
    align-items: center;
    font-weight: 700;
    font-size: 2rem;
    color: var(--text-primary);
    text-decoration: none;
}

.logo-icon {
    margin-right: 1rem;
}

.nav-links {
    display: flex;
    list-style: none;
}

.nav-links li {
    margin-left: 2.5rem;
}

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

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

/* Hero Section */
.hero {
    padding: 6rem 0;
    background-color: var(--background-light);
}

.hero .container {
    display: flex;
    align-items: center;
    gap: 4rem;
}

.hero-content {
    flex: 1;
}

.app-icon-container {
    display: flex;
    justify-content: center;
    margin-bottom: 2rem;
}

.app-icon {
    width: 80px;
    height: 80px;
    border-radius: 20px;
    box-shadow: var(--shadow-sm);
}

.hero-image {
    flex: 1;
    display: flex;
    justify-content: center;
    align-items: center;
}

.hero .app-preview {
    max-width: 80%;
    height: auto;
    border-radius: var(--border-radius);
    box-shadow: var(--shadow-md);
}

.hero h1 {
    font-size: 4.8rem;
    line-height: 1.2;
    margin-bottom: 2rem;
    color: var(--text-primary);
}

.hero p {
    font-size: 1.8rem;
    color: var(--text-secondary);
    margin-bottom: 3rem;
}

.hero-buttons {
    display: flex;
    flex-wrap: wrap;
    gap: 1.5rem;
}

.btn {
    display: inline-flex;
    align-items: center;
    padding: 1.2rem 2.4rem;
    border-radius: var(--border-radius);
    font-weight: 500;
    text-decoration: none;
    transition: var(--transition);
    border: none;
    cursor: pointer;
    font-size: 1.6rem;
}

.btn-icon {
    margin-right: 1rem;
}

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

.btn-primary:hover {
    background-color: #FF5252;
    transform: translateY(-2px);
    box-shadow: var(--shadow-sm);
}

.btn-secondary {
    background-color: var(--secondary-color);
    color: var(--text-light);
}

.btn-secondary:hover {
    background-color: #3B9EFF;
    transform: translateY(-2px);
    box-shadow: var(--shadow-sm);
}

.btn-large {
    padding: 1.5rem 3rem;
    font-size: 1.8rem;
}

/* Features Section */
.features {
    padding: 8rem 0;
    background-color: var(--background-off);
}

.section-title {
    text-align: center;
    font-size: 3.6rem;
    margin-bottom: 6rem;
    color: var(--text-primary);
}

.features-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(25rem, 1fr));
    gap: 3rem;
}

.feature-card {
    background-color: var(--background-light);
    border-radius: var(--border-radius);
    padding: 3rem;
    box-shadow: var(--shadow-sm);
    transition: var(--transition);
}

.feature-card:hover {
    transform: translateY(-5px);
    box-shadow: var(--shadow-md);
}

.feature-icon {
    margin-bottom: 2rem;
}

.feature-card h3 {
    font-size: 2.2rem;
    margin-bottom: 1.5rem;
    color: var(--text-primary);
}

.feature-card p {
    font-size: 1.6rem;
    color: var(--text-secondary);
}

/* App Preview Section */
.app-preview {
    padding: 8rem 0;
    width: 100%;
    display: flex;
    justify-content: center;
}

.app-preview .container {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 6rem;
}

.app-preview-content {
    flex: 1;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    text-align: center;
    margin: 0 auto;
    max-width: 100%;
}

.app-screenshot {
    flex: 1;
    display: flex;
    justify-content: center;
}

.screenshot-img {
    max-width: 75%;
    height: auto;
    border-radius: var(--border-radius);
    box-shadow: var(--shadow-md);
}

.app-preview-content h2 {
    font-size: 3.6rem;
    line-height: 1.2;
    margin-bottom: 2rem;
    color: var(--text-primary);
}

.app-preview-content p {
    font-size: 1.8rem;
    color: var(--text-secondary);
    margin-bottom: 3rem;
}

.app-features-list {
    list-style: none;
    padding: 0;
    margin: 0 auto;
    max-width: 350px;
    display: inline-block;
    text-align: left;
}

.app-features-list li {
    display: flex;
    align-items: center;
    margin-bottom: 1.5rem;
    font-size: 1.8rem;
    color: var(--text-primary);
}

.app-features-list li svg {
    margin-right: 1.5rem;
    flex-shrink: 0;
}

/* Download Section */
.download {
    padding: 8rem 0;
    background-color: var(--background-off);
    text-align: center;
}

.section-description {
    font-size: 1.8rem;
    color: var(--text-secondary);
    margin: 0 auto 4rem;
    max-width: 70rem;
}

.download-icon-container {
    display: flex;
    justify-content: center;
    margin-bottom: 3rem;
}

.download-app-icon {
    width: 120px;
    height: 120px;
    border-radius: 30px;
    box-shadow: var(--shadow-md);
    transition: var(--transition);
}

.download-app-icon:hover {
    transform: scale(1.05);
}

.download-buttons {
    display: flex;
    justify-content: center;
    gap: 2rem;
    flex-wrap: wrap;
}

/* Contact Section */
.contact {
    padding: 8rem 0;
    text-align: center;
}

.contact-info {
    margin-top: 4rem;
    display: flex;
    justify-content: center;
    align-items: center;
}

.social-link {
    display: inline-flex;
    align-items: center;
    font-size: 1.8rem;
    color: var(--text-primary);
    text-decoration: none;
    transition: var(--transition);
}

.social-link:hover {
    color: var(--primary-color);
}

.social-link svg {
    margin-right: 1rem;
}

/* Footer */
.footer {
    background-color: var(--text-primary);
    color: var(--text-light);
    padding: 4rem 0;
}

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

.footer-logo {
    display: flex;
    align-items: center;
    font-weight: 700;
    font-size: 1.8rem;
    color: var(--text-light);
}

.copyright {
    font-size: 1.4rem;
    color: rgba(255, 255, 255, 0.7);
}

/* Responsive Design */
@media (max-width: 992px) {
    html {
        font-size: 60%;
    }
    
    .hero .container,
    .app-preview .container {
        flex-direction: column;
        text-align: center;
    }
    
    .app-features-list {
        width: 100%;
        max-width: 300px;
        display: inline-block;
    }
    
    .hero-image,
    .app-screenshot {
        margin-top: 4rem;
    }
    
    .screenshot-img {
        max-width: 65%;
    }
    
    .footer-content {
        flex-direction: column;
        gap: 2rem;
    }
}

@media (max-width: 768px) {
    .nav {
        flex-direction: column;
        gap: 1.5rem;
    }
    
    .nav-links {
        width: 100%;
        justify-content: center;
    }
    
    .nav-links li {
        margin: 0 1rem;
    }
    
    .hero h1 {
        font-size: 3.6rem;
    }
    
    .features-grid {
        grid-template-columns: 1fr;
    }
    
    .download-buttons {
        flex-direction: column;
        align-items: center;
    }
    
    .app-preview-content h2 {
        font-size: 3rem;
    }
}

@media (max-width: 480px) {
    .hero h1 {
        font-size: 3rem;
    }
    
    .app-preview-content h2 {
        font-size: 2.6rem;
    }
    
    .section-title {
        font-size: 2.8rem;
    }
    
    .screenshot-img {
        max-width: 85%;
    }
    
    .btn {
        width: 100%;
        justify-content: center;
    }
}