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

:root {
    --primary: #1B3564;
    --accent: #2874B8;
    --bg: #FFFFFF;
    --surface: #F5F7FA;
    --border: #E2E8F0;
    --text: #1A202C;
    --text-secondary: #4A5568;
    --max-width: 860px;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, "Hiragino Kaku Gothic ProN", "Hiragino Sans", "Yu Gothic", "Meiryo", sans-serif;
    font-size: 16px;
    line-height: 1.8;
    color: var(--text);
    background: var(--bg);
}

a {
    color: var(--accent);
    text-decoration: none;
}

a:hover {
    text-decoration: underline;
}

/* ========== Header ========== */
.site-header {
    background: var(--primary);
    color: white;
}

.site-header-inner {
    max-width: var(--max-width);
    margin: 0 auto;
    padding: 18px 24px;
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 16px;
}

.site-logo {
    font-size: 1.4rem;
    font-weight: 700;
    color: white;
    text-decoration: none;
    letter-spacing: 0.04em;
    line-height: 1.2;
}

.site-logo:hover {
    text-decoration: none;
    opacity: 0.9;
}

.site-logo small {
    font-size: 0.7rem;
    font-weight: 400;
    display: block;
    opacity: 0.75;
    letter-spacing: 0.02em;
    margin-top: 2px;
}

.site-nav {
    display: flex;
    gap: 24px;
    list-style: none;
}

.site-nav a {
    color: rgba(255, 255, 255, 0.88);
    font-size: 0.875rem;
    text-decoration: none;
    padding-bottom: 2px;
    border-bottom: 2px solid transparent;
    transition: border-color 0.2s;
    white-space: nowrap;
}

.site-nav a:hover {
    border-bottom-color: rgba(255, 255, 255, 0.6);
    text-decoration: none;
}

/* ========== Hero ========== */
.hero {
    background: linear-gradient(135deg, #1B3564 0%, #2256a0 100%);
    color: white;
    padding: 60px 24px;
    text-align: center;
}

.hero-inner {
    max-width: var(--max-width);
    margin: 0 auto;
}

.hero h1 {
    font-size: 2rem;
    font-weight: 700;
    margin-bottom: 20px;
    line-height: 1.4;
    border: none;
    color: white;
    padding: 0;
}

.hero p {
    font-size: 1rem;
    opacity: 0.92;
    max-width: 620px;
    margin: 0 auto 10px;
    line-height: 1.9;
}

.hero-badge {
    display: inline-block;
    background: rgba(255,255,255,0.15);
    border: 1px solid rgba(255,255,255,0.3);
    color: white;
    font-size: 0.8rem;
    padding: 4px 14px;
    border-radius: 20px;
    margin-bottom: 20px;
    letter-spacing: 0.05em;
}

/* ========== Main ========== */
main {
    max-width: var(--max-width);
    margin: 0 auto;
    padding: 48px 24px 64px;
}

/* ========== Typography ========== */
h1 {
    font-size: 1.7rem;
    font-weight: 700;
    color: var(--primary);
    margin-bottom: 24px;
    padding-bottom: 12px;
    border-bottom: 3px solid var(--accent);
    line-height: 1.4;
}

h2 {
    font-size: 1.3rem;
    font-weight: 700;
    color: var(--primary);
    margin: 40px 0 16px;
    padding-bottom: 8px;
    border-bottom: 1px solid var(--border);
}

h3 {
    font-size: 1.05rem;
    font-weight: 700;
    color: var(--text);
    margin: 28px 0 12px;
}

p {
    margin-bottom: 16px;
}

ul, ol {
    margin: 0 0 16px 1.5em;
}

li {
    margin-bottom: 6px;
}

strong {
    font-weight: 700;
}

hr {
    border: none;
    border-top: 1px solid var(--border);
    margin: 32px 0;
}

/* ========== Intro block ========== */
.intro {
    background: var(--surface);
    border-left: 4px solid var(--accent);
    padding: 20px 24px;
    margin-bottom: 40px;
    border-radius: 0 6px 6px 0;
}

.intro p {
    margin: 0;
    color: var(--text-secondary);
    line-height: 1.8;
}

/* ========== Form section ========== */
.form-section {
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: 10px;
    padding: 32px;
    margin: 40px 0;
}

.form-section-title {
    font-size: 1.1rem;
    font-weight: 700;
    color: var(--primary);
    margin-bottom: 8px;
}

.form-section-note {
    font-size: 0.875rem;
    color: var(--text-secondary);
    margin-bottom: 24px;
}

/* ========== Backnumber list ========== */
.backnumber-list {
    list-style: none;
    margin: 0;
    padding: 0;
    border-top: 1px solid var(--border);
}

.backnumber-list li {
    border-bottom: 1px solid var(--border);
    margin: 0;
}

.backnumber-list a {
    display: grid;
    grid-template-columns: 60px 140px 1fr;
    align-items: center;
    gap: 16px;
    padding: 16px 12px;
    color: var(--text);
    text-decoration: none;
    transition: background 0.15s;
}

.backnumber-list a:hover {
    background: var(--surface);
    text-decoration: none;
}

.issue-number {
    color: var(--accent);
    font-size: 0.85rem;
    font-weight: 700;
    white-space: nowrap;
}

.issue-date {
    color: var(--text-secondary);
    font-size: 0.85rem;
    white-space: nowrap;
}

.issue-title {
    font-weight: 500;
    line-height: 1.5;
}

/* ========== Download list ========== */
.download-list {
    list-style: none;
    margin: 0;
    padding: 0;
    display: grid;
    gap: 14px;
}

.download-item {
    border: 1px solid var(--border);
    border-radius: 8px;
    padding: 20px 24px;
    display: flex;
    align-items: center;
    gap: 16px;
    text-decoration: none;
    color: var(--text);
    transition: box-shadow 0.2s, border-color 0.2s;
    background: white;
}

.download-item:hover {
    box-shadow: 0 2px 12px rgba(0, 0, 0, 0.08);
    border-color: var(--accent);
    text-decoration: none;
}

.download-item-badge {
    background: var(--primary);
    color: white;
    font-size: 0.75rem;
    font-weight: 700;
    padding: 4px 10px;
    border-radius: 4px;
    white-space: nowrap;
    flex-shrink: 0;
}

.download-item-title {
    font-weight: 600;
    flex: 1;
    line-height: 1.5;
}

.download-item-arrow {
    color: var(--accent);
    font-size: 1.1rem;
    flex-shrink: 0;
}

/* ========== Article (backnumber detail) ========== */
.article-header {
    margin-bottom: 36px;
    padding-bottom: 20px;
    border-bottom: 1px solid var(--border);
}

.article-meta {
    display: flex;
    gap: 16px;
    align-items: center;
    color: var(--text-secondary);
    font-size: 0.875rem;
    margin-bottom: 12px;
}

.article-meta .issue-tag {
    background: var(--primary);
    color: white;
    font-size: 0.75rem;
    font-weight: 700;
    padding: 3px 10px;
    border-radius: 4px;
}

.article-content {
    line-height: 1.95;
}

.article-content h1 {
    font-size: 1.5rem;
    border-bottom: none;
    padding: 0;
    color: var(--primary);
    margin-bottom: 28px;
}

.article-content h2 {
    font-size: 1.2rem;
    margin-top: 44px;
    color: var(--primary);
}

.article-content h3 {
    font-size: 1.0rem;
    margin-top: 28px;
}

.article-content p {
    margin-bottom: 20px;
}

.article-content ul,
.article-content ol {
    margin-bottom: 20px;
}

.article-content blockquote {
    border-left: 4px solid var(--accent);
    padding: 12px 20px;
    background: var(--surface);
    margin: 24px 0;
    color: var(--text-secondary);
    border-radius: 0 6px 6px 0;
}

.article-content blockquote p {
    margin: 0;
}

/* ========== Breadcrumb ========== */
.breadcrumb {
    font-size: 0.85rem;
    color: var(--text-secondary);
    margin-bottom: 32px;
}

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

.breadcrumb a:hover {
    text-decoration: underline;
}

.breadcrumb span {
    margin: 0 8px;
    color: var(--border);
}

/* ========== Back link ========== */
.back-link {
    display: inline-flex;
    align-items: center;
    gap: 6px;
    color: var(--accent);
    font-size: 0.9rem;
    margin-top: 48px;
    padding: 10px 18px;
    border: 1px solid var(--accent);
    border-radius: 6px;
    text-decoration: none;
    transition: background 0.2s;
}

.back-link:hover {
    background: var(--surface);
    text-decoration: none;
}

/* ========== CTA section ========== */
.cta-section {
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: 10px;
    padding: 28px 32px;
    margin: 48px 0 32px;
    text-align: center;
}

.cta-section p {
    margin-bottom: 14px;
    color: var(--text-secondary);
}

.cta-button {
    display: inline-block;
    background: var(--accent);
    color: white;
    padding: 12px 28px;
    border-radius: 6px;
    font-weight: 600;
    font-size: 0.95rem;
    text-decoration: none;
    transition: background 0.2s;
}

.cta-button:hover {
    background: var(--primary);
    text-decoration: none;
}

/* ========== Notice / Placeholder ========== */
.notice-box {
    background: #FFF8E6;
    border: 1px solid #F5C842;
    border-radius: 8px;
    padding: 20px 24px;
    margin: 32px 0;
    color: #7A5C00;
    font-size: 0.95rem;
}

/* ========== Footer ========== */
.site-footer {
    background: var(--primary);
    color: rgba(255, 255, 255, 0.78);
    padding: 40px 24px 32px;
}

.site-footer-inner {
    max-width: var(--max-width);
    margin: 0 auto;
    display: flex;
    justify-content: space-between;
    align-items: flex-start;
    gap: 24px;
    flex-wrap: wrap;
}

.footer-brand .footer-logo {
    font-size: 1.1rem;
    font-weight: 700;
    color: white;
    display: block;
    margin-bottom: 6px;
}

.site-footer p {
    font-size: 0.825rem;
    margin: 0;
    opacity: 0.7;
}

.footer-links {
    list-style: none;
    display: flex;
    flex-wrap: wrap;
    gap: 8px 20px;
    align-items: center;
}

.footer-links a {
    color: rgba(255, 255, 255, 0.78);
    font-size: 0.875rem;
    text-decoration: none;
    transition: color 0.2s;
}

.footer-links a:hover {
    color: white;
    text-decoration: none;
}

.footer-divider {
    border: none;
    border-top: 1px solid rgba(255,255,255,0.12);
    margin: 24px 0 16px;
}

.footer-copyright {
    max-width: var(--max-width);
    margin: 0 auto;
    font-size: 0.8rem;
    opacity: 0.5;
    text-align: center;
}

/* ========== Responsive ========== */
@media (max-width: 640px) {
    .site-header-inner {
        flex-direction: column;
        align-items: flex-start;
        gap: 14px;
    }

    .site-nav {
        gap: 16px;
    }

    .hero h1 {
        font-size: 1.5rem;
    }

    h1 {
        font-size: 1.4rem;
    }

    .backnumber-list a {
        grid-template-columns: 60px 1fr;
    }

    .issue-date {
        display: none;
    }

    .form-section {
        padding: 24px 16px;
    }

    .cta-section {
        padding: 20px 16px;
    }

    .site-footer-inner {
        flex-direction: column;
    }
}