*,*::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:#00695c;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:#00695c;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:#00695c;font-weight:600;border-bottom:2px solid #00695c}
.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-river{padding:40px 0 24px;border-bottom:1px solid #b2dfdb}
.hero-tag{display:inline-block;font-size:.78rem;font-weight:600;letter-spacing:.06em;color:#00695c;background:#e0f2f1;padding:4px 12px;border-radius:4px;margin-bottom:14px}
.hero-river h1{font-size:1.68rem;line-height:1.38;margin-bottom:16px;color:#111;max-width:840px}
.hero-river .lead{color:#444;margin-bottom:12px;font-size:1.02rem;max-width:840px}
.hero-river .lead:last-of-type{margin-bottom:0}

.river-nav-wrap{background:#fff;border-bottom:1px solid #e0e0e0;position:sticky;top:61px;z-index:90}
.river-nav{display:flex;justify-content:flex-start;flex-wrap:nowrap;gap:0;padding:0;list-style:none;overflow-x:auto;-webkit-overflow-scrolling:touch;scrollbar-width:thin}
.river-nav li{flex-shrink:0}
.river-nav a{display:block;font-size:.84rem;color:#555;padding:12px 18px;border-bottom:3px solid transparent;white-space:nowrap;transition:.15s}
.river-nav a:hover,.river-nav a.is-active{color:#00695c;border-bottom-color:#00695c;text-decoration:none;font-weight:600}

.river-flow{padding:40px 0 20px;position:relative}
.river-flow::before{content:"";position:absolute;left:50%;top:0;bottom:0;width:3px;background:linear-gradient(180deg,#80cbc4,#00695c,#80cbc4);transform:translateX(-50%);border-radius:2px;z-index:0}

.river-node{position:relative;display:grid;grid-template-columns:1fr 48px 1fr;gap:0;margin-bottom:48px;scroll-margin-top:120px}
.river-node:last-child{margin-bottom:0}
.node-marker{grid-column:2;display:flex;flex-direction:column;align-items:center;position:relative;z-index:1}
.node-dot{width:20px;height:20px;border-radius:50%;background:#fff;border:3px solid #00695c;transition:.2s;flex-shrink:0;margin-top:28px}
.river-node.is-active .node-dot{background:#00695c;box-shadow:0 0 0 6px rgba(0,105,92,.18)}
.node-label{font-size:.68rem;font-weight:700;color:#00695c;letter-spacing:.06em;margin-top:8px;writing-mode:vertical-rl;text-orientation:mixed}

.river-panel{padding:24px 28px;background:#fff;border:1px solid #b2dfdb;border-radius:10px;position:relative;z-index:1;transition:.2s}
.river-node.is-active .river-panel{border-color:#00695c;box-shadow:0 4px 16px rgba(0,105,92,.1)}
.river-panel h2{font-size:1.12rem;margin-bottom:12px;color:#111;line-height:1.4}
.river-panel p{margin-bottom:10px;color:#333;font-size:.97rem}
.river-panel p:last-child{margin-bottom:0}
.river-panel .panel-img{margin:14px 0;border-radius:8px;overflow:hidden;border:1px solid #b2dfdb}
.river-panel .panel-img figcaption{font-size:.8rem;color:#666;padding:6px 10px;background:#f5f5f5}
.river-panel .tip-box{background:#e0f2f1;border-left:3px solid #00695c;padding:10px 14px;margin:12px 0;font-size:.92rem;color:#004d40}

.river-node:nth-child(odd) .river-panel{grid-column:1;grid-row:1}
.river-node:nth-child(odd) .node-marker{grid-column:2;grid-row:1}
.river-node:nth-child(even) .river-panel{grid-column:3;grid-row:1}
.river-node:nth-child(even) .node-marker{grid-column:2;grid-row:1}

.river-node.span-center{grid-template-columns:1fr;display:block;margin-top:8px}
.river-node.span-center .node-marker{display:none}
.river-node.span-center .river-panel{max-width:760px;margin:0 auto}

.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:8px;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:#00695c;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:#00695c;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}
  .river-flow::before{left:24px;transform:none}
  .river-node{grid-template-columns:48px 1fr;gap:0 16px;margin-bottom:36px}
  .river-node:nth-child(odd) .river-panel,
  .river-node:nth-child(even) .river-panel{grid-column:2;grid-row:1}
  .river-node:nth-child(odd) .node-marker,
  .river-node:nth-child(even) .node-marker{grid-column:1;grid-row:1}
  .node-label{display:none}
  .node-dot{margin-top:24px}
  .river-nav-wrap{top:57px}
  .hero-river h1{font-size:1.36rem}
}