/* ==========================================
   CSS Variables (カラースキーム)
   ========================================== */
:root {
    /* メインカラー（青系 - 信頼感） */
    --primary-color: #0066CC;
    --primary-dark: #004C99;
    --primary-light: #3385D6;
    
    /* アクセントカラー（グリーン - 仮想通貨） */
    --accent-color: #00D084;
    --accent-dark: #00A66B;
    
    /* ニュートラルカラー */
    --bg-color: #FFFFFF;
    --bg-secondary: #F7F9FC;
    --bg-tertiary: #E8EDF5;
    --text-color: #333333;
    --text-secondary: #666666;
    --border-color: #DDE3ED;
    
    /* ランキングカラー */
    --gold: #FFD700;
    --silver: #C0C0C0;
    --bronze: #CD7F32;
    
    /* シャドウ */
    --shadow-sm: 0 2px 4px 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);
    
    /* フォント */
    --font-main: -apple-system, BlinkMacSystemFont, "Segoe UI", "Helvetica Neue", "Hiragino Kaku Gothic ProN", "Hiragino Sans", "BIZ UDPGothic", Meiryo, sans-serif;
}

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

html {
    scroll-behavior: smooth;
}

body {
    font-family: var(--font-main);
    color: var(--text-color);
    background-color: var(--bg-color);
    line-height: 1.7;
    font-size: 16px;
}

a {
    text-decoration: none;
    color: var(--primary-color);
    transition: color 0.3s;
}

a:hover {
    color: var(--primary-dark);
}

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

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

/* ==========================================
   Header
   ========================================== */
.header {
    background: #fff;
    border-bottom: 1px solid var(--border-color);
    position: sticky;
    top: 0;
    z-index: 100;
    box-shadow: var(--shadow-sm);
}

.header-content {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 16px 0;
}

.logo h1 {
    font-size: 28px;
    font-weight: 700;
    margin-bottom: 4px;
}

.logo h1 a {
    color: var(--primary-color);
}

.logo .tagline {
    font-size: 12px;
    color: var(--text-secondary);
}

.nav ul {
    display: flex;
    list-style: none;
    gap: 32px;
}

.nav a {
    color: var(--text-color);
    font-weight: 500;
    padding: 8px 0;
    position: relative;
}

.nav a::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 0;
    width: 0;
    height: 2px;
    background: var(--primary-color);
    transition: width 0.3s;
}

.nav a:hover::after {
    width: 100%;
}

/* ==========================================
   Hero Section
   ========================================== */
.hero {
    background: linear-gradient(135deg, #0066CC 0%, #0052A3 100%);
    color: white;
    padding: 80px 0;
    text-align: center;
}

.hero-title {
    font-size: 48px;
    font-weight: 700;
    margin-bottom: 16px;
    line-height: 1.2;
}

.hero-subtitle {
    font-size: 20px;
    margin-bottom: 40px;
    opacity: 0.95;
}

.hero-search {
    max-width: 600px;
    margin: 0 auto 40px;
    display: flex;
    gap: 12px;
}

.search-input {
    flex: 1;
    padding: 16px 24px;
    font-size: 16px;
    border: none;
    border-radius: 8px;
    outline: none;
}

.search-btn {
    padding: 16px 32px;
    background: var(--accent-color);
    color: white;
    border: none;
    border-radius: 8px;
    font-size: 16px;
    font-weight: 600;
    cursor: pointer;
    transition: background 0.3s;
}

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

.hero-stats {
    display: flex;
    justify-content: center;
    gap: 60px;
    margin-top: 40px;
}

.stat-item {
    display: flex;
    flex-direction: column;
    align-items: center;
}

.stat-number {
    font-size: 36px;
    font-weight: 700;
    color: var(--accent-color);
}

.stat-label {
    font-size: 14px;
    opacity: 0.9;
    margin-top: 4px;
}

/* ==========================================
   Section Titles
   ========================================== */
.section-title {
    font-size: 36px;
    font-weight: 700;
    text-align: center;
    margin-bottom: 12px;
    color: var(--text-color);
}

.section-subtitle {
    text-align: center;
    color: var(--text-secondary);
    margin-bottom: 48px;
    font-size: 16px;
}

/* ==========================================
   Ranking Section
   ========================================== */
.ranking {
    padding: 80px 0;
    background: var(--bg-secondary);
}

.ranking-list {
    display: flex;
    flex-direction: column;
    gap: 32px;
}

.ranking-card {
    background: white;
    border-radius: 12px;
    padding: 32px;
    box-shadow: var(--shadow-md);
    display: flex;
    gap: 24px;
    position: relative;
    transition: transform 0.3s, box-shadow 0.3s;
}

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

.rank-badge {
    display: flex;
    flex-direction: column;
    align-items: center;
    min-width: 80px;
}

.rank-number {
    font-size: 48px;
    font-weight: 700;
    color: var(--text-secondary);
}

.rank-1 .rank-number {
    color: var(--gold);
}

.rank-2 .rank-number {
    color: var(--silver);
}

.rank-3 .rank-number {
    color: var(--bronze);
}

.rank-crown {
    font-size: 40px;
    margin-top: 8px;
}

.card-content {
    flex: 1;
}

.card-header {
    margin-bottom: 24px;
}

.card-name {
    font-size: 28px;
    font-weight: 700;
    margin-bottom: 12px;
    color: var(--text-color);
}

.card-tags {
    display: flex;
    gap: 8px;
    flex-wrap: wrap;
}

.tag {
    padding: 4px 12px;
    border-radius: 16px;
    font-size: 12px;
    font-weight: 600;
}

.tag-recommended {
    background: #FFF3CD;
    color: #856404;
}

.tag-beginner {
    background: #D1ECF1;
    color: #0C5460;
}

.tag-cashback {
    background: #D4EDDA;
    color: #155724;
}

.tag-advanced {
    background: #E2E3E5;
    color: #383D41;
}

.tag-domestic {
    background: #CCE5FF;
    color: #004085;
}

.tag-safe {
    background: #D4EDDA;
    color: #155724;
}

.card-features {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 20px;
    margin-bottom: 24px;
}

.feature-highlight {
    display: flex;
    gap: 12px;
    padding: 16px;
    background: var(--bg-secondary);
    border-radius: 8px;
}

.feature-icon {
    font-size: 32px;
}

.feature-highlight strong {
    display: block;
    margin-bottom: 4px;
    color: var(--text-color);
}

.feature-highlight p {
    font-size: 14px;
    color: var(--text-secondary);
}

.card-specs table {
    width: 100%;
    margin-bottom: 24px;
    font-size: 14px;
}

.card-specs th {
    text-align: left;
    padding: 12px;
    background: var(--bg-secondary);
    font-weight: 600;
    width: 30%;
}

.card-specs td {
    padding: 12px;
    border-bottom: 1px solid var(--border-color);
}

.card-actions {
    display: flex;
    gap: 12px;
}

.btn {
    padding: 14px 32px;
    border-radius: 8px;
    font-weight: 600;
    font-size: 15px;
    text-align: center;
    cursor: pointer;
    transition: all 0.3s;
    border: none;
    display: inline-block;
}

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

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

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

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

/* ==========================================
   Comparison Table Section
   ========================================== */
.comparison {
    padding: 80px 0;
}

.table-wrapper {
    overflow-x: auto;
    box-shadow: var(--shadow-md);
    border-radius: 12px;
}

.comparison-table {
    width: 100%;
    border-collapse: collapse;
    background: white;
    font-size: 14px;
}

.comparison-table thead {
    background: var(--primary-color);
    color: white;
}

.comparison-table th {
    padding: 16px;
    text-align: left;
    font-weight: 600;
    white-space: nowrap;
}

.comparison-table td {
    padding: 16px;
    border-bottom: 1px solid var(--border-color);
}

.comparison-table tbody tr:hover {
    background: var(--bg-secondary);
}

.highlight-row {
    background: #FFF9E6 !important;
}

.rank-cell {
    font-weight: 700;
    white-space: nowrap;
}

.name-cell {
    font-weight: 700;
    color: var(--text-color);
}

.highlight {
    color: var(--accent-color);
    font-weight: 700;
}

.link-btn {
    color: var(--primary-color);
    font-weight: 600;
    white-space: nowrap;
}

.link-btn:hover {
    text-decoration: underline;
}

/* ==========================================
   Guide Section
   ========================================== */
.guide {
    padding: 80px 0;
    background: var(--bg-secondary);
}

.guide-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 32px;
}

.guide-item {
    background: white;
    padding: 32px;
    border-radius: 12px;
    box-shadow: var(--shadow-md);
    text-align: center;
    transition: transform 0.3s;
}

.guide-item:hover {
    transform: translateY(-8px);
}

.guide-icon {
    font-size: 60px;
    margin-bottom: 20px;
}

.guide-item h3 {
    font-size: 20px;
    margin-bottom: 12px;
    color: var(--text-color);
}

.guide-item p {
    color: var(--text-secondary);
    line-height: 1.7;
}

/* ==========================================
   FAQ Section
   ========================================== */
.faq {
    padding: 80px 0;
}

.faq-list {
    max-width: 800px;
    margin: 0 auto;
}

.faq-item {
    background: white;
    margin-bottom: 16px;
    border-radius: 8px;
    box-shadow: var(--shadow-sm);
    overflow: hidden;
}

.faq-item summary {
    padding: 20px 24px;
    font-size: 18px;
    font-weight: 600;
    cursor: pointer;
    user-select: none;
    list-style: none;
    display: flex;
    justify-content: space-between;
    align-items: center;
    background: var(--bg-secondary);
}

.faq-item summary::-webkit-details-marker {
    display: none;
}

.faq-item summary::after {
    content: '+';
    font-size: 24px;
    font-weight: 700;
    color: var(--primary-color);
}

.faq-item[open] summary::after {
    content: '−';
}

.faq-item p {
    padding: 20px 24px;
    color: var(--text-secondary);
    line-height: 1.8;
}

/* ==========================================
   Footer
   ========================================== */
.footer {
    background: #1A2332;
    color: #E8EDF5;
    padding: 60px 0 20px;
}

.footer-content {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 40px;
    margin-bottom: 40px;
}

.footer-section h4 {
    font-size: 18px;
    margin-bottom: 16px;
    color: white;
}

.footer-section p {
    font-size: 14px;
    line-height: 1.7;
    color: #B8C5D6;
}

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

.footer-section li {
    margin-bottom: 12px;
}

.footer-section a {
    color: #B8C5D6;
    font-size: 14px;
    transition: color 0.3s;
}

.footer-section a:hover {
    color: white;
}

.footer-bottom {
    border-top: 1px solid rgba(255, 255, 255, 0.1);
    padding-top: 24px;
    text-align: center;
    font-size: 13px;
    color: #B8C5D6;
}

.disclaimer {
    margin-top: 8px;
    font-size: 12px;
    opacity: 0.7;
}

/* ==========================================
   Responsive Design
   ========================================== */
@media (max-width: 768px) {
    .hero-title {
        font-size: 32px;
    }
    
    .hero-subtitle {
        font-size: 16px;
    }
    
    .hero-search {
        flex-direction: column;
    }
    
    .hero-stats {
        flex-direction: column;
        gap: 20px;
    }
    
    .section-title {
        font-size: 28px;
    }
    
    .ranking-card {
        flex-direction: column;
    }
    
    .rank-badge {
        flex-direction: row;
        gap: 12px;
    }
    
    .card-name {
        font-size: 22px;
    }
    
    .card-features {
        grid-template-columns: 1fr;
    }
    
    .card-actions {
        flex-direction: column;
    }
    
    .nav ul {
        gap: 16px;
    }
    
    .nav a {
        font-size: 14px;
    }
}

@media (max-width: 480px) {
    .hero {
        padding: 40px 0;
    }
    
    .section-title {
        font-size: 24px;
    }
    
    .ranking,
    .comparison,
    .guide,
    .faq {
        padding: 40px 0;
    }
}