/* ========================================
   リセット & ベース
   ======================================== */

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

:root {
    /* ダークモード（デフォルト） */
    --bg-primary: #0a0a0a;
    --bg-secondary: #151515;
    --bg-tertiary: #1f1f1f;
    --text-primary: #f5f5f5;
    --text-secondary: #a0a0a0;
    --text-tertiary: #707070;
    --border-color: rgba(255, 255, 255, 0.1);
    --accent-primary: #6366f1;
    --accent-hover: #4f46e5;
    --accent-light: rgba(99, 102, 241, 0.1);
    --success: #10b981;
    --success-light: rgba(16, 185, 129, 0.1);
    --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.3);
    --shadow-md: 0 4px 12px rgba(0, 0, 0, 0.4);
    --shadow-lg: 0 8px 24px rgba(0, 0, 0, 0.5);
}

[data-theme="light"] {
    --bg-primary: #ffffff;
    --bg-secondary: #f9fafb;
    --bg-tertiary: #f3f4f6;
    --text-primary: #111827;
    --text-secondary: #6b7280;
    --text-tertiary: #9ca3af;
    --border-color: rgba(0, 0, 0, 0.1);
    --accent-primary: #6366f1;
    --accent-hover: #4f46e5;
    --accent-light: rgba(99, 102, 241, 0.08);
    --success: #059669;
    --success-light: rgba(5, 150, 105, 0.08);
    --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.05);
    --shadow-md: 0 4px 12px rgba(0, 0, 0, 0.08);
    --shadow-lg: 0 8px 24px rgba(0, 0, 0, 0.12);
}

html {
    scroll-behavior: smooth;
}

@media (prefers-reduced-motion: reduce) {
    html {
        scroll-behavior: auto;
    }
    
    *,
    *::before,
    *::after {
        animation-duration: 0.01ms !important;
        animation-iteration-count: 1 !important;
        transition-duration: 0.01ms !important;
    }
}

body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "Helvetica Neue", Arial, "Noto Sans", sans-serif, "Apple Color Emoji", "Segoe UI Emoji", "Segoe UI Symbol";
    background-color: var(--bg-primary);
    color: var(--text-primary);
    line-height: 1.7;
    font-size: 16px;
    transition: background-color 0.3s ease, color 0.3s ease, opacity 0.2s ease;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 24px;
}

/* ========================================
   ヒーローセクション
   ======================================== */

.hero {
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    position: relative;
    padding: 80px 0;
    opacity: 0;
    transform: translateY(20px);
    animation: fadeInUp 0.5s ease forwards;
}

@keyframes fadeInUp {
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.top-controls {
    position: absolute;
    top: 32px;
    right: 32px;
    display: flex;
    align-items: center;
    gap: 12px;
}

.theme-toggle {
    background: var(--bg-secondary);
    border: 1px solid var(--border-color);
    border-radius: 12px;
    padding: 12px 16px;
    cursor: pointer;
    display: flex;
    align-items: center;
    gap: 8px;
    font-size: 20px;
    transition: all 0.2s ease;
    box-shadow: var(--shadow-sm);
}

.theme-toggle:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-md);
}

.theme-toggle:focus {
    outline: 2px solid var(--accent-primary);
    outline-offset: 2px;
}

.theme-icon {
    display: none;
}

[data-theme="dark"] .theme-icon.moon {
    display: inline;
}

[data-theme="light"] .theme-icon.sun {
    display: inline;
}

.language-switcher {
    display: inline-flex;
    align-items: center;
}

.language-select {
    appearance: none;
    border: 1px solid var(--border-color);
    background: var(--bg-secondary);
    color: var(--text-primary);
    border-radius: 10px;
    padding: 10px 36px 10px 14px;
    font-size: 0.9rem;
    font-weight: 600;
    box-shadow: var(--shadow-sm);
    cursor: pointer;
    transition: all 0.2s ease;
}

.language-select:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-md);
}

.language-select:focus {
    outline: 2px solid var(--accent-primary);
    outline-offset: 2px;
}

.language-switcher::after {
    content: "▾";
    position: relative;
    margin-left: -22px;
    color: var(--text-secondary);
    pointer-events: none;
    font-size: 0.75rem;
}

.page-fade-out {
    opacity: 0;
}

.sr-only {
    position: absolute;
    width: 1px;
    height: 1px;
    padding: 0;
    margin: -1px;
    overflow: hidden;
    clip: rect(0, 0, 0, 0);
    border: 0;
}

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

.hero-title {
    font-size: clamp(2.5rem, 5vw, 4rem);
    font-weight: 700;
    letter-spacing: -0.02em;
    line-height: 1.2;
    margin-bottom: 24px;
}

.hero-subtitle-inline {
    display: block;
    font-size: clamp(2rem, 4vw, 3rem);
    color: var(--text-secondary);
    font-weight: 600;
    margin-top: 12px;
}

.hero-description {
    font-size: clamp(1.125rem, 2vw, 1.25rem);
    color: var(--text-secondary);
    line-height: 1.8;
    margin-bottom: 40px;
    max-width: 600px;
    margin-left: auto;
    margin-right: auto;
}

.hero-cta {
    display: flex;
    gap: 16px;
    justify-content: center;
    flex-wrap: wrap;
}

/* ========================================
   ボタン
   ======================================== */

.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    padding: 14px 32px;
    font-size: 1rem;
    font-weight: 500;
    border-radius: 10px;
    text-decoration: none;
    transition: all 0.2s ease;
    cursor: pointer;
    border: none;
}

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

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

.btn-primary:focus {
    outline: 2px solid var(--accent-primary);
    outline-offset: 2px;
}

.btn-secondary {
    background: var(--bg-secondary);
    color: var(--text-primary);
    border: 1px solid var(--border-color);
    box-shadow: var(--shadow-sm);
}

.btn-secondary:hover {
    background: var(--bg-tertiary);
    transform: translateY(-2px);
    box-shadow: var(--shadow-md);
}

.btn-secondary:focus {
    outline: 2px solid var(--accent-primary);
    outline-offset: 2px;
}

/* ========================================
   比較セクション
   ======================================== */

.comparison {
    padding: 120px 0;
    opacity: 0;
    transform: translateY(30px);
}

.comparison.visible {
    animation: fadeInUp 0.5s ease forwards;
}

.comparison-badge {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    background: var(--success-light);
    color: var(--success);
    padding: 10px 20px;
    border-radius: 24px;
    font-size: 0.9rem;
    font-weight: 500;
    margin-bottom: 48px;
}

.badge-icon {
    color: var(--success);
}

.comparison-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 32px;
    margin-bottom: 48px;
}

.comparison-column {
    background: var(--bg-secondary);
    border: 1px solid var(--border-color);
    border-radius: 16px;
    padding: 40px 32px;
    transition: all 0.3s ease;
}

.comparison-column:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-lg);
}

.comparison-column.premium {
    background: linear-gradient(135deg, var(--bg-secondary) 0%, rgba(99, 102, 241, 0.05) 100%);
    border-color: rgba(99, 102, 241, 0.2);
}

.column-header {
    margin-bottom: 32px;
    position: relative;
}

.premium-badge {
    display: inline-block;
    background: linear-gradient(135deg, var(--accent-primary), var(--accent-hover));
    color: white;
    padding: 4px 12px;
    border-radius: 6px;
    font-size: 0.75rem;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.05em;
    margin-bottom: 12px;
}

.column-title {
    font-size: 1.75rem;
    font-weight: 700;
    margin-bottom: 8px;
}

.column-subtitle {
    font-size: 1rem;
    color: var(--text-secondary);
}

.feature-list {
    list-style: none;
    display: flex;
    flex-direction: column;
    gap: 20px;
}

.feature-item {
    display: flex;
    gap: 16px;
    align-items: flex-start;
}

.check-icon {
    flex-shrink: 0;
    color: var(--success);
    margin-top: 2px;
}

.feature-content {
    display: flex;
    flex-direction: column;
    gap: 4px;
}

.feature-content strong {
    font-weight: 600;
    color: var(--text-primary);
}

.feature-content span {
    font-size: 0.9rem;
    color: var(--text-secondary);
    line-height: 1.5;
}

.comparison-note {
    display: flex;
    align-items: flex-start;
    gap: 12px;
    background: var(--accent-light);
    border: 1px solid rgba(99, 102, 241, 0.2);
    border-radius: 12px;
    padding: 20px 24px;
    color: var(--text-primary);
    font-size: 0.95rem;
    line-height: 1.6;
}

.note-icon {
    flex-shrink: 0;
    color: var(--accent-primary);
    margin-top: 2px;
}

/* ========================================
   詳細説明セクション
   ======================================== */

.details {
    padding: 120px 0;
    background: var(--bg-secondary);
    opacity: 0;
    transform: translateY(30px);
}

.details.visible {
    animation: fadeInUp 0.5s ease forwards;
}

.details-content {
    max-width: 800px;
    margin: 0 auto;
}

.section-title {
    font-size: clamp(2rem, 4vw, 2.5rem);
    font-weight: 700;
    margin-bottom: 24px;
    letter-spacing: -0.01em;
}

.section-intro {
    font-size: 1.125rem;
    color: var(--text-secondary);
    line-height: 1.8;
    margin-bottom: 48px;
}

.details-section {
    margin-bottom: 48px;
}

.subsection-title {
    font-size: 1.5rem;
    font-weight: 600;
    margin-bottom: 16px;
    color: var(--text-primary);
}

.subsection-text {
    color: var(--text-secondary);
    line-height: 1.8;
    margin-bottom: 20px;
}

.details-list {
    list-style: none;
    display: flex;
    flex-direction: column;
    gap: 12px;
    padding-left: 0;
}

.details-list li {
    padding-left: 28px;
    position: relative;
    color: var(--text-secondary);
    line-height: 1.7;
}

.details-list li::before {
    content: "•";
    position: absolute;
    left: 12px;
    color: var(--accent-primary);
    font-weight: bold;
}

/* ========================================
   FAQセクション
   ======================================== */

.faq {
    padding: 120px 0;
    opacity: 0;
    transform: translateY(30px);
}

.faq.visible {
    animation: fadeInUp 0.5s ease forwards;
}

.faq-list {
    max-width: 800px;
    margin: 48px auto 0;
    display: flex;
    flex-direction: column;
    gap: 16px;
}

.faq-item {
    background: var(--bg-secondary);
    border: 1px solid var(--border-color);
    border-radius: 12px;
    overflow: hidden;
    transition: all 0.2s ease;
}

.faq-item:hover {
    border-color: rgba(99, 102, 241, 0.3);
}

.faq-question {
    width: 100%;
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 24px 28px;
    background: transparent;
    border: none;
    color: var(--text-primary);
    font-size: 1.125rem;
    font-weight: 600;
    text-align: left;
    cursor: pointer;
    transition: background 0.2s ease;
}

.faq-question:hover {
    background: var(--bg-tertiary);
}

.faq-question:focus {
    outline: 2px solid var(--accent-primary);
    outline-offset: -2px;
}

.faq-question-text {
    flex: 1;
}

.faq-icon {
    flex-shrink: 0;
    color: var(--text-secondary);
    transition: transform 0.3s ease;
}

.faq-question[aria-expanded="true"] .faq-icon {
    transform: rotate(180deg);
}

.faq-answer {
    max-height: 0;
    overflow: hidden;
    transition: max-height 0.3s ease;
}

.faq-answer p {
    padding: 0 28px 24px 28px;
    color: var(--text-secondary);
    line-height: 1.8;
}

/* ========================================
   フッター
   ======================================== */

.footer {
    padding: 60px 0 40px;
    background: var(--bg-secondary);
    border-top: 1px solid var(--border-color);
}

.footer-links {
    display: flex;
    gap: 32px;
    justify-content: center;
    margin-bottom: 24px;
    flex-wrap: wrap;
}

.footer-link {
    color: var(--text-secondary);
    text-decoration: none;
    font-size: 0.9rem;
    transition: color 0.2s ease;
}

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

.footer-link:focus {
    outline: 2px solid var(--accent-primary);
    outline-offset: 2px;
    border-radius: 4px;
}

.footer-copyright {
    text-align: center;
    color: var(--text-tertiary);
    font-size: 0.875rem;
}

/* ========================================
   レスポンシブ
   ======================================== */

@media (max-width: 768px) {
    .container {
        padding: 0 20px;
    }
    
    .hero {
        min-height: auto;
        padding: 60px 0;
    }
    
    .top-controls {
        top: 20px;
        right: 20px;
    }
    
    .hero-cta {
        flex-direction: column;
        align-items: stretch;
    }
    
    .btn {
        width: 100%;
    }
    
    .comparison,
    .details,
    .faq {
        padding: 80px 0;
    }
    
    .comparison-grid {
        grid-template-columns: 1fr;
        gap: 24px;
    }
    
    .comparison-column {
        padding: 32px 24px;
    }
    
    .faq-question {
        padding: 20px 24px;
        font-size: 1rem;
    }
    
    .faq-answer p {
        padding: 0 24px 20px 24px;
    }
}

@media (max-width: 480px) {
    .comparison-badge {
        font-size: 0.8rem;
        padding: 8px 16px;
    }
    
    .feature-item {
        gap: 12px;
    }
    
    .check-icon {
        width: 20px;
        height: 20px;
    }
}