*,*::before,*::after{box-sizing:border-box;margin:0;padding:0}
body{font-family:"Noto Sans SC",system-ui,sans-serif;background:#fff;color:#1a1a1a;line-height:1.75;font-size:16px}
a{color:#1565c0;text-decoration:none}
a:hover{text-decoration:underline}
img{max-width:100%;height:auto;display:block}
.container{max-width:1100px;margin:0 auto;padding:0 20px}

.site-header{background:#fff;border-bottom:1px solid #e8e8e8;position:sticky;top:0;z-index:100}
.header-row{display:flex;align-items:center;justify-content:space-between;padding:14px 0}
.brand{display:flex;align-items:center;gap:10px;font-size:1.05rem;color:#1a1a1a;font-weight:500}
.brand:hover{text-decoration:none}
.brand b{color:#1565c0;font-weight:700}
.site-nav ul{display:flex;gap:6px 18px;list-style:none;flex-wrap:wrap}
.site-nav a{color:#444;font-size:.92rem;padding:4px 0}
.site-nav a.active{color:#1565c0;font-weight:600;border-bottom:2px solid #1565c0}
.nav-toggle{display:none;background:none;border:none;cursor:pointer;padding:8px;flex-direction:column;gap:5px}
.nav-toggle span{display:block;width:22px;height:2px;background:#333;transition:.2s}
.nav-toggle.is-open span:nth-child(1){transform:translateY(7px) rotate(45deg)}
.nav-toggle.is-open span:nth-child(2){opacity:0}
.nav-toggle.is-open span:nth-child(3){transform:translateY(-7px) rotate(-45deg)}

.ads-top-bar{background:#fafafa;border-bottom:1px solid #eee;padding:10px 0}
.applist-title{font-size:.78rem;color:#888;text-align:center;margin-bottom:6px;letter-spacing:.05em}
#ads{display:flex;justify-content:center;flex-wrap:wrap;gap:12px}
#ads .caption{font-size:.7rem;color:#666;margin-top:4px;text-align:center;max-width:70px;line-height:1.3}

.hero-board{padding:40px 0 28px;border-bottom:2px solid #1565c0}
.hero-board h1{font-size:1.72rem;line-height:1.38;margin-bottom:16px;color:#111;max-width:820px}
.hero-board .lead{color:#444;margin-bottom:12px;font-size:1.02rem;max-width:820px}
.hero-board .lead:last-of-type{margin-bottom:0}

.board-nav-wrap{background:#fff;border-bottom:1px solid #e0e0e0;position:sticky;top:61px;z-index:90}
.board-nav{display:flex;justify-content:center;flex-wrap:wrap;gap:8px 14px;padding:12px 0;list-style:none}
.board-nav a{display:inline-flex;align-items:center;gap:6px;font-size:.85rem;color:#555;padding:6px 14px;border:1px solid #ddd;border-radius:20px;transition:.15s}
.board-nav a::before{content:"";width:8px;height:8px;border-radius:2px;background:#bbdefb;transition:.15s}
.board-nav a:hover,.board-nav a.is-active{color:#1565c0;border-color:#1565c0;text-decoration:none}
.board-nav a.is-active::before{background:#1565c0}

.board-grid{display:grid;grid-template-columns:1fr 1fr;gap:0;border:2px solid #1565c0;margin:32px 0 0}
.board-cell{padding:28px 26px;border:1px solid #1565c0;position:relative}
.board-cell:nth-child(4n+1),.board-cell:nth-child(4n+4){background:#fff}
.board-cell:nth-child(4n+2),.board-cell:nth-child(4n+3){background:#e3f2fd}
.board-cell .cell-num{position:absolute;top:12px;right:16px;font-size:.72rem;font-weight:700;color:#1565c0;opacity:.6;letter-spacing:.08em}
.board-cell h2{font-size:1.12rem;margin-bottom:12px;color:#111;line-height:1.4;padding-right:40px}
.board-cell p{margin-bottom:10px;color:#333;font-size:.97rem}
.board-cell p:last-child{margin-bottom:0}
.board-cell .cell-img{margin:14px 0;border-radius:6px;overflow:hidden;border:1px solid #90caf9}
.board-cell .cell-img figcaption{font-size:.8rem;color:#666;padding:6px 10px;background:#fafafa}
.board-cell .note-box{background:#fff;border-left:3px solid #1565c0;padding:10px 14px;margin:12px 0;font-size:.92rem;color:#0d47a1}

.board-cell.span-full{grid-column:1/-1;background:#fff;border-top:2px solid #1565c0}

.faq{padding:36px 0 48px;border-top:1px solid #eee}
.faq h2{font-size:1.25rem;margin-bottom:18px;color:#111}
.faq details{border:1px solid #e0e0e0;border-radius:6px;margin-bottom:10px;background:#fff}
.faq summary{padding:14px 18px;cursor:pointer;font-weight:500;color:#333;list-style:none}
.faq summary::-webkit-details-marker{display:none}
.faq summary::before{content:"+";display:inline-block;width:20px;color:#1565c0;font-weight:700}
.faq details[open] summary::before{content:"−"}
.faq details p{padding:0 18px 14px;color:#444;font-size:.95rem}

.site-footer{background:#fafafa;border-top:1px solid #eee;padding:28px 0;margin-top:20px}
.footer-links{display:flex;flex-wrap:wrap;gap:8px 20px;margin-bottom:10px}
.footer-links a{font-size:.88rem;color:#555}
.site-footer p{font-size:.82rem;color:#888}

.prose-page{padding:36px 0 48px;max-width:760px}
.prose-page h1{font-size:1.5rem;margin-bottom:16px;color:#111}
.prose-page h2{font-size:1.1rem;margin:20px 0 10px;color:#222}
.prose-page p{margin-bottom:12px;color:#333}

.error-page{text-align:center;padding:48px 0 16px}
.error-page h1{font-size:3rem;color:#1565c0;line-height:1}

@media(max-width:768px){
  .nav-toggle{display:flex}
  .site-nav{display:none;position:absolute;top:100%;left:0;right:0;background:#fff;border-bottom:1px solid #eee;padding:12px 20px;box-shadow:0 4px 12px rgba(0,0,0,.06)}
  .site-nav.is-open{display:block}
  .site-nav ul{flex-direction:column;gap:10px}
  .header-row{position:relative}
  .board-grid{grid-template-columns:1fr}
  .board-cell:nth-child(even){background:#e3f2fd}
  .board-cell:nth-child(odd){background:#fff}
  .board-nav-wrap{top:57px}
  .hero-board h1{font-size:1.38rem}
}