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

:root {
    --primary-color: #0066cc;
    --primary-dark: #004d99;
    --text-color: #333;
    --text-light: #666;
    --bg-light: #f8f9fa;
    --white: #ffffff;
    --border-color: #e0e0e0;
    --shadow: 0 2px 8px rgba(0, 0, 0, 0.1);
    --shadow-hover: 0 4px 16px rgba(0, 0, 0, 0.15);
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'Hiragino Sans', 'Hiragino Kaku Gothic ProN', Meiryo, sans-serif;
    color: var(--text-color);
    line-height: 1.6;
}

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

.header {
    background: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(10px);
    box-shadow: var(--shadow);
    position: sticky;
    top: 0;
    z-index: 100;
}

.nav {
    padding: 1rem 0;
}

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

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

.nav-actions {
    display: flex;
    align-items: center;
    gap: 1rem;
}

.language-selector {
    position: relative;
}

.language-dropdown {
    padding: 0.5rem 2.5rem 0.5rem 1rem;
    color: var(--primary-color);
    font-weight: 600;
    border: 2px solid var(--primary-color);
    border-radius: 6px;
    background: var(--white);
    cursor: pointer;
    font-size: 0.95rem;
    font-family: inherit;
    transition: all 0.3s ease;
    appearance: none;
    background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='12' height='12' viewBox='0 0 12 12'%3E%3Cpath fill='%230066cc' d='M6 9L1 4h10z'/%3E%3C/svg%3E");
    background-repeat: no-repeat;
    background-position: right 0.7rem center;
    background-size: 12px;
}

.language-dropdown:hover {
    background-color: rgba(0, 102, 204, 0.05);
    border-color: var(--primary-dark);
}

.language-dropdown:focus {
    outline: none;
    border-color: var(--primary-dark);
    box-shadow: 0 0 0 3px rgba(0, 102, 204, 0.1);
}

.language-dropdown option {
    padding: 0.5rem;
    background: var(--white);
    color: var(--text-color);
}

.btn-primary {
    background: var(--primary-color);
    color: var(--white);
    padding: 0.75rem 1.5rem;
    border-radius: 8px;
    text-decoration: none;
    font-weight: 600;
    transition: background 0.3s ease;
}

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

.hero {
    padding: 4rem 0;
    background: linear-gradient(135deg, #f5f7fa 0%, #c3cfe2 100%);
}

.hero .container {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 3rem;
    align-items: center;
}

.hero-title {
    font-size: 3rem;
    font-weight: 800;
    color: var(--text-color);
    margin-bottom: 1rem;
}

.hero-subtitle {
    font-size: 1.5rem;
    color: var(--text-light);
    margin-bottom: 1rem;
}

.hero-description {
    font-size: 1.125rem;
    color: var(--text-light);
    margin-bottom: 2rem;
}

.btn-cta {
    display: inline-block;
    background: var(--primary-color);
    color: var(--white);
    padding: 1rem 2rem;
    border-radius: 8px;
    text-decoration: none;
    font-weight: 600;
    font-size: 1.125rem;
    transition: all 0.3s ease;
    box-shadow: var(--shadow);
}

.btn-cta:hover {
    background: var(--primary-dark);
    box-shadow: var(--shadow-hover);
    transform: translateY(-2px);
}

.btn-cta.large {
    padding: 1.25rem 3rem;
    font-size: 1.25rem;
}

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

.product-image {
    width: 100%;
    max-width: 500px;
    height: auto;
    border-radius: 16px;
    box-shadow: 0 8px 24px rgba(0, 0, 0, 0.2);
    transition: all 0.4s ease;
    animation: float 3s ease-in-out infinite;
}

.product-image:hover {
    transform: scale(1.05);
    box-shadow: 0 12px 32px rgba(0, 0, 0, 0.3);
}

@keyframes float {
    0%, 100% {
        transform: translateY(0px);
    }
    50% {
        transform: translateY(-10px);
    }
}

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

.features {
    padding: 5rem 0;
    background: linear-gradient(180deg, #ffffff 0%, #f8f9fa 100%);
    position: relative;
}

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

.feature-card {
    background: var(--white);
    padding: 2rem;
    border-radius: 12px;
    box-shadow: var(--shadow);
    transition: all 0.3s ease;
    text-align: center;
    border: 1px solid transparent;
}

.feature-card:hover {
    box-shadow: 0 8px 24px rgba(0, 102, 204, 0.15);
    transform: translateY(-8px);
    border-color: rgba(0, 102, 204, 0.1);
}

.feature-icon {
    margin-bottom: 1.5rem;
    display: flex;
    justify-content: center;
}

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

.feature-description {
    color: var(--text-light);
    line-height: 1.8;
}

.usage {
    padding: 5rem 0;
    background: var(--bg-light);
}

.usage-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 2rem;
}

.usage-item {
    background: var(--white);
    padding: 2rem;
    border-radius: 12px;
    box-shadow: var(--shadow);
    border-left: 4px solid var(--primary-color);
    transition: all 0.3s ease;
}

.usage-item:hover {
    box-shadow: 0 6px 20px rgba(0, 0, 0, 0.12);
    transform: translateX(4px);
}

.usage-title {
    font-size: 1.25rem;
    font-weight: 600;
    margin-bottom: 0.75rem;
    color: var(--primary-color);
}

.usage-description {
    color: var(--text-light);
    line-height: 1.8;
}

.product-details {
    padding: 5rem 0;
    background: var(--white);
}

.details-content {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 4rem;
    align-items: center;
}

.details-image-container {
    display: flex;
    align-items: center;
    justify-content: center;
}

.details-product-image {
    width: 100%;
    max-width: 450px;
    height: auto;
    border-radius: 12px;
    box-shadow: 0 4px 16px rgba(0, 0, 0, 0.15);
    transition: all 0.3s ease;
}

.details-product-image:hover {
    transform: scale(1.03);
    box-shadow: 0 6px 20px rgba(0, 0, 0, 0.2);
}

.details-grid {
    display: grid;
    grid-template-columns: 1fr;
    gap: 1.5rem;
}

.detail-item {
    display: flex;
    justify-content: space-between;
    padding: 1.5rem;
    background: var(--bg-light);
    border-radius: 8px;
    border: 1px solid var(--border-color);
}

.detail-label {
    font-weight: 600;
    color: var(--text-color);
}

.detail-value {
    color: var(--text-light);
    text-align: right;
}

.cta-section {
    padding: 5rem 0;
    background: linear-gradient(135deg, var(--primary-color) 0%, var(--primary-dark) 100%);
    color: var(--white);
    position: relative;
    overflow: hidden;
}

.cta-section::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: radial-gradient(circle at 30% 50%, rgba(255, 255, 255, 0.1) 0%, transparent 50%);
    animation: pulse 4s ease-in-out infinite;
}

@keyframes pulse {
    0%, 100% {
        opacity: 1;
    }
    50% {
        opacity: 0.5;
    }
}

.cta-content {
    text-align: center;
    position: relative;
    z-index: 1;
}

.cta-title {
    font-size: 2.5rem;
    font-weight: 700;
    margin-bottom: 1rem;
}

.cta-description {
    font-size: 1.25rem;
    margin-bottom: 2rem;
    opacity: 0.9;
}

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

.cta-section .btn-cta:hover {
    background: var(--bg-light);
}

.footer {
    background: #2c3e50;
    color: var(--white);
    padding: 2rem 0;
    text-align: center;
}

.footer-text {
    opacity: 0.8;
}

@media (max-width: 768px) {
    .nav .container {
        flex-wrap: wrap;
        gap: 0.5rem;
    }

    .nav-actions {
        gap: 0.5rem;
    }

    .language-dropdown {
        padding: 0.4rem 2rem 0.4rem 0.8rem;
        font-size: 0.85rem;
        background-position: right 0.5rem center;
    }

    .btn-primary {
        padding: 0.6rem 1.2rem;
        font-size: 0.9rem;
    }

    .hero .container {
        grid-template-columns: 1fr;
        gap: 2rem;
    }

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

    .hero-subtitle {
        font-size: 1.25rem;
    }

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

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

    .details-content {
        grid-template-columns: 1fr;
        gap: 2rem;
    }

    .details-product-image {
        max-width: 100%;
    }

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

    .detail-item {
        flex-direction: column;
        gap: 0.5rem;
    }

    .detail-value {
        text-align: left;
    }

    .cta-title {
        font-size: 1.75rem;
    }

    .product-image {
        max-width: 100%;
    }
}