*,*::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:#00796b;text-decoration:none}
a:hover{text-decoration:underline}
img{max-width:100%;height:auto;display:block}
.container{max-width:1080px;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:#00796b;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:#00796b;font-weight:600;border-bottom:2px solid #00796b}
.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-zigzag{padding:40px 0 32px;border-bottom:1px solid #eee}
.hero-zigzag h1{font-size:1.68rem;line-height:1.38;margin-bottom:18px;color:#111;max-width:780px}
.hero-zigzag .lead{color:#444;margin-bottom:14px;font-size:1.02rem;max-width:780px}
.hero-zigzag .lead:last-of-type{margin-bottom:0}

.zigzag-shell{display:grid;grid-template-columns:180px 1fr;gap:32px;padding:36px 0 20px;align-items:start}
.zigzag-rail{position:sticky;top:88px}
.zigzag-rail ol{list-style:none;counter-reset:chap;border-left:2px solid #b2dfdb;padding-left:0}
.zigzag-rail li{counter-increment:chap;margin-bottom:4px}
.zigzag-rail a{display:flex;align-items:center;gap:10px;padding:10px 0 10px 18px;font-size:.88rem;color:#555;transition:color .15s}
.zigzag-rail a::before{content:counter(chap);flex-shrink:0;width:26px;height:26px;border-radius:50%;background:#e0f2f1;color:#00796b;font-size:.78rem;font-weight:700;display:flex;align-items:center;justify-content:center;margin-left:-31px;border:2px solid #fff}
.zigzag-rail a:hover,.zigzag-rail a.is-active{color:#00796b;text-decoration:none;font-weight:600}
.zigzag-rail a.is-active::before{background:#00796b;color:#fff}

.zigzag-flow{display:flex;flex-direction:column;gap:0}
.zig-row{display:grid;grid-template-columns:1fr 1fr;gap:28px;align-items:center;padding:28px 0;position:relative}
.zig-row::after{content:"";position:absolute;left:50%;bottom:-1px;width:12px;height:12px;background:#00796b;border-radius:50%;transform:translateX(-50%);z-index:1}
.zig-row:last-child::after{display:none}
.zig-row:nth-child(odd) .zig-text{order:1}
.zig-row:nth-child(odd) .zig-visual{order:2}
.zig-row:nth-child(even) .zig-text{order:2}
.zig-row:nth-child(even) .zig-visual{order:1}
.zig-text{padding:22px 24px;background:#fff;border:1px solid #e8e8e8;border-radius:10px}
.zig-text .chap-tag{display:inline-block;font-size:.72rem;font-weight:600;letter-spacing:.06em;color:#00796b;background:#e0f2f1;padding:3px 10px;border-radius:4px;margin-bottom:10px}
.zig-text h2{font-size:1.14rem;margin-bottom:12px;color:#111;line-height:1.4}
.zig-text p{margin-bottom:10px;color:#333;font-size:.97rem}
.zig-text p:last-child{margin-bottom:0}
.zig-visual{border-radius:10px;overflow:hidden;border:1px solid #e8e8e8}
.zig-visual figcaption{font-size:.82rem;color:#777;padding:8px 12px;background:#fafafa}
.zig-text .tip-box{background:#e0f2f1;border-left:3px solid #00796b;padding:12px 16px;margin:14px 0;border-radius:0 6px 6px 0;font-size:.93rem;color:#004d40}

.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 #e8e8e8;border-radius:8px;margin-bottom:10px;padding:0}
.faq summary{padding:14px 18px;cursor:pointer;font-weight:500;color:#222;list-style:none}
.faq summary::-webkit-details-marker{display:none}
.faq details[open] summary{border-bottom:1px solid #eee;background:#fafafa}
.faq details p{padding:14px 18px;color:#444;font-size:.95rem}

.site-footer{background:#fafafa;border-top:1px solid #eee;padding:28px 0;margin-top:20px;text-align:center;font-size:.88rem;color:#666}
.footer-links{display:flex;flex-wrap:wrap;justify-content:center;gap:8px 16px;margin-bottom:10px}
.footer-links a{color:#555}

.prose-page{padding:32px 0 48px}
.prose-page h1{font-size:1.5rem;margin-bottom:16px}
.prose-page h2{font-size:1.15rem;margin:24px 0 10px;color:#222}
.prose-page p{margin-bottom:12px;color:#333}
.error-page{text-align:center;padding:48px 0 24px}
.error-page h1{font-size:3rem;color:#00796b}

@media(max-width:860px){
  .zigzag-shell{grid-template-columns:1fr}
  .zigzag-rail{position:static;margin-bottom:8px}
  .zigzag-rail ol{display:flex;flex-wrap:wrap;gap:6px;border-left:none}
  .zigzag-rail li{margin:0}
  .zigzag-rail a{padding:6px 12px;border:1px solid #e8e8e8;border-radius:20px;background:#fafafa;margin:0}
  .zigzag-rail a::before{display:none}
  .zig-row{grid-template-columns:1fr;gap:16px}
  .zig-row::after{display:none}
  .zig-row:nth-child(odd) .zig-text,.zig-row:nth-child(odd) .zig-visual,
  .zig-row:nth-child(even) .zig-text,.zig-row:nth-child(even) .zig-visual{order:unset}
  .nav-toggle{display:flex}
  .site-nav{position:absolute;top:100%;left:0;right:0;background:#fff;border-bottom:1px solid #eee;padding:12px 20px;display:none}
  .site-nav.is-open{display:block}
  .site-nav ul{flex-direction:column;gap:10px}
  .site-header .container{position:relative}
}