:root {
    --primary: #E60012;
    --primary-dark: #C8000F;
    --primary-light: rgba(230, 0, 18, 0.08);
    --bg-white: #FFFFFF;
    --bg-light: #F5F5F7;
    --bg-dark: #1A1A1A;
    --text-primary: #1A1A1A;
    --text-secondary: #666666;
    --text-light: #999999;
    --text-white: #FFFFFF;
    --border-light: rgba(0, 0, 0, 0.06);
    --shadow-sm: 0 2px 8px rgba(0, 0, 0, 0.04);
    --shadow-md: 0 8px 30px rgba(0, 0, 0, 0.08);
    --shadow-lg: 0 20px 60px rgba(0, 0, 0, 0.12);
    --radius-sm: 12px;
    --radius-md: 20px;
    --radius-lg: 32px;
    --radius-full: 100px;
    --transition: all 0.4s cubic-bezier(0.16, 1, 0.3, 1);
}

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

html {
    scroll-behavior: smooth;
}

body {
    font-family: 'Noto Sans JP', 'Inter', -apple-system, BlinkMacSystemFont, sans-serif;
    line-height: 1.8;
    color: var(--text-primary);
    background: var(--bg-white);
}

/* Header */
header {
    position: sticky;
    top: 0;
    z-index: 1000;
    background: rgba(255, 255, 255, 0.92);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    border-bottom: 1px solid var(--border-light);
}

.header-inner {
    max-width: 1200px;
    margin: 0 auto;
    padding: 1rem 2rem;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.logo-link {
    text-decoration: none;
}

.logo {
    font-size: 1.5rem;
    font-weight: 900;
    color: var(--primary);
    letter-spacing: -0.02em;
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.logo::before {
    content: '';
    width: 28px;
    height: 28px;
    background: var(--primary);
    border-radius: 6px;
}

.nav-links {
    display: flex;
    gap: 1.5rem;
    list-style: none;
}

.nav-links a {
    text-decoration: none;
    color: var(--text-secondary);
    font-weight: 600;
    font-size: 0.9rem;
    transition: var(--transition);
}

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

/* Article Header */
.article-header {
    background: var(--bg-light);
    padding: 80px 2rem 60px;
}

.article-header-inner {
    max-width: 800px;
    margin: 0 auto;
}

.breadcrumb {
    display: flex;
    gap: 0.5rem;
    font-size: 0.85rem;
    color: var(--text-light);
    margin-bottom: 2rem;
    flex-wrap: wrap;
}

.breadcrumb a {
    color: var(--text-secondary);
    text-decoration: none;
    transition: var(--transition);
}

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

.article-tag {
    display: inline-block;
    font-family: 'Inter', sans-serif;
    font-size: 0.75rem;
    font-weight: 700;
    letter-spacing: 0.12em;
    color: var(--primary);
    background: var(--primary-light);
    padding: 0.5rem 1rem;
    border-radius: var(--radius-full);
    margin-bottom: 1.5rem;
}

.article-header h1 {
    font-size: clamp(1.75rem, 4vw, 2.5rem);
    font-weight: 900;
    line-height: 1.4;
    margin-bottom: 1.5rem;
}

.article-meta {
    display: flex;
    gap: 2rem;
    color: var(--text-secondary);
    font-size: 0.9rem;
}

/* Article Content */
.article-content {
    max-width: 800px;
    margin: 0 auto;
    padding: 60px 2rem 80px;
}

.article-content p {
    font-size: 1.05rem;
    line-height: 2.2;
    color: var(--text-secondary);
    margin-bottom: 2rem;
}

.article-content h2 {
    font-size: 1.5rem;
    font-weight: 800;
    color: var(--text-primary);
    margin: 3rem 0 1.5rem;
    padding-bottom: 0.75rem;
    border-bottom: 3px solid var(--primary);
}

.article-content h3 {
    font-size: 1.2rem;
    font-weight: 700;
    color: var(--text-primary);
    margin: 2rem 0 1rem;
}

.article-content ul,
.article-content ol {
    margin: 1.5rem 0 2rem 1.5rem;
    color: var(--text-secondary);
}

.article-content li {
    margin-bottom: 0.75rem;
    line-height: 2;
}

/* Highlight Box */
.highlight-box {
    background: var(--primary-light);
    border-left: 4px solid var(--primary);
    padding: 1.5rem 2rem;
    border-radius: 0 var(--radius-sm) var(--radius-sm) 0;
    margin: 2rem 0;
}

.highlight-box p {
    margin: 0;
    color: var(--text-primary);
    font-weight: 500;
}

/* Template Box */
.template-box {
    background: var(--bg-light);
    border-radius: var(--radius-md);
    padding: 2rem;
    margin: 2rem 0;
}

.template-box h4 {
    font-size: 1rem;
    font-weight: 700;
    color: var(--primary);
    margin-bottom: 1rem;
}

.template-content {
    background: var(--bg-white);
    border: 1px solid var(--border-light);
    border-radius: var(--radius-sm);
    padding: 1.5rem;
    font-size: 0.95rem;
    line-height: 2;
    color: var(--text-secondary);
    white-space: pre-wrap;
}

/* Example Box */
.example-box {
    background: var(--bg-dark);
    border-radius: var(--radius-md);
    padding: 2rem;
    margin: 2rem 0;
}

.example-box h4 {
    font-size: 1rem;
    font-weight: 700;
    color: var(--text-white);
    margin-bottom: 1rem;
}

.example-content {
    background: rgba(255, 255, 255, 0.05);
    border-radius: var(--radius-sm);
    padding: 1.5rem;
    font-size: 0.95rem;
    line-height: 2;
    color: rgba(255, 255, 255, 0.8);
    white-space: pre-wrap;
}

/* Tip Box */
.tip-box {
    background: #E8F5E9;
    border-left: 4px solid #4CAF50;
    padding: 1.5rem 2rem;
    border-radius: 0 var(--radius-sm) var(--radius-sm) 0;
    margin: 2rem 0;
}

.tip-box p {
    margin: 0;
    color: #2E7D32;
}

/* Warning Box */
.warning-box {
    background: #FFF3E0;
    border-left: 4px solid #FF9800;
    padding: 1.5rem 2rem;
    border-radius: 0 var(--radius-sm) var(--radius-sm) 0;
    margin: 2rem 0;
}

.warning-box p {
    margin: 0;
    color: #E65100;
}

/* CTA Section */
.cta-section {
    padding: 60px 2rem;
    background: var(--bg-white);
}

.cta-box {
    max-width: 800px;
    margin: 0 auto;
    padding: 3rem;
    background: linear-gradient(135deg, var(--primary) 0%, var(--primary-dark) 100%);
    border-radius: var(--radius-lg);
    text-align: center;
    color: var(--text-white);
}

.cta-box h2 {
    font-size: 1.5rem;
    font-weight: 800;
    margin-bottom: 1rem;
}

.cta-box p {
    margin-bottom: 2rem;
    opacity: 0.9;
}

.btn {
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    padding: 1rem 2.5rem;
    font-size: 0.95rem;
    font-weight: 700;
    text-decoration: none;
    border-radius: var(--radius-full);
    transition: var(--transition);
}

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

.btn-white:hover {
    transform: translateY(-3px);
    box-shadow: var(--shadow-lg);
}

/* Footer */
footer {
    background: var(--bg-dark);
    padding: 60px 2rem 40px;
    color: var(--text-white);
}

.footer-inner {
    max-width: 1200px;
    margin: 0 auto;
    display: flex;
    justify-content: space-between;
    align-items: center;
    flex-wrap: wrap;
    gap: 2rem;
}

.footer-logo {
    font-size: 1.25rem;
    font-weight: 900;
    color: var(--primary);
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.footer-logo::before {
    content: '';
    width: 24px;
    height: 24px;
    background: var(--primary);
    border-radius: 4px;
}

.footer-links {
    display: flex;
    gap: 2rem;
    flex-wrap: wrap;
}

.footer-links a {
    color: rgba(255, 255, 255, 0.7);
    text-decoration: none;
    font-size: 0.9rem;
    transition: var(--transition);
}

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

.footer-bottom {
    max-width: 1200px;
    margin: 40px auto 0;
    padding-top: 30px;
    border-top: 1px solid rgba(255, 255, 255, 0.1);
    text-align: center;
    color: rgba(255, 255, 255, 0.4);
    font-size: 0.85rem;
}

/* Responsive */
@media (max-width: 768px) {
    .header-inner {
        padding: 1rem;
    }

    .nav-links {
        gap: 1rem;
        font-size: 0.85rem;
    }

    .article-header {
        padding: 60px 1.5rem 40px;
    }

    .article-content {
        padding: 40px 1.5rem 60px;
    }

    .article-meta {
        flex-direction: column;
        gap: 0.5rem;
    }

    .template-box,
    .example-box {
        padding: 1.5rem;
    }
}