/* 无限臀山 - 户外极限运动与探险社区 主样式 */
:root{
  --primary:#37474F;
  --secondary:#FF6D00;
  --bg:#FAFAFA;
  --card-bg:#FFFFFF;
  --accent:#FF9100;
  --text:#1A1A1A;
  --muted:#6b7480;
  --border:#e6e6e6;
  --radius:10px;
  --shadow:0 6px 24px rgba(0,0,0,.08);
  --maxw:1200px;
}
*{box-sizing:border-box;margin:0;padding:0}
html{scroll-behavior:smooth}
body{font-family:"Noto Sans SC","Roboto","Helvetica Neue",Arial,sans-serif;background:var(--bg);color:var(--text);line-height:1.7;-webkit-font-smoothing:antialiased}
h1,h2,h3,h4{font-family:"Montserrat","Oswald","Noto Sans SC",sans-serif;font-weight:800;color:var(--primary);letter-spacing:.5px;line-height:1.25}
h1{font-size:clamp(2rem,4vw,3.4rem)}
h2{font-size:clamp(1.6rem,2.5vw,2.2rem);margin-bottom:1rem}
h3{font-size:1.25rem;margin-bottom:.5rem}
p{margin-bottom:1rem;color:#333}
a{color:var(--secondary);text-decoration:none;transition:color .2s}
a:hover{color:var(--accent)}
img{max-width:100%;height:auto;display:block}
.container{max-width:var(--maxw);margin:0 auto;padding:0 20px}

/* Header */
.site-header{position:fixed;top:0;left:0;right:0;z-index:100;background:rgba(55,71,79,.92);backdrop-filter:blur(10px);transition:all .3s;border-bottom:1px solid rgba(255,255,255,.08)}
.site-header.scrolled{background:rgba(55,71,79,.96);box-shadow:0 2px 12px rgba(0,0,0,.18)}
.nav{display:flex;align-items:center;justify-content:space-between;padding:14px 20px;max-width:var(--maxw);margin:0 auto}
.brand{display:flex;align-items:center;gap:10px;color:#fff;font-family:"Montserrat",sans-serif;font-weight:900;font-size:1.3rem}
.brand img{width:38px;height:38px;border-radius:8px}
.nav-links{display:flex;gap:24px;list-style:none}
.nav-links a{color:#fff;font-weight:500;font-size:.95rem;position:relative}
.nav-links a:hover{color:var(--accent)}
.nav-links a::after{content:"";position:absolute;left:0;bottom:-6px;width:0;height:2px;background:var(--secondary);transition:width .25s}
.nav-links a:hover::after{width:100%}
.menu-toggle{display:none;background:none;border:0;color:#fff;font-size:1.6rem;cursor:pointer}
@media(max-width:860px){
  .nav-links{display:none;position:absolute;top:64px;left:0;right:0;background:var(--primary);flex-direction:column;padding:18px;gap:14px}
  .nav-links.open{display:flex}
  .menu-toggle{display:block}
}

/* Hero */
.hero{position:relative;min-height:100vh;display:flex;align-items:center;justify-content:center;color:#fff;text-align:center;background:linear-gradient(rgba(26,26,26,.55),rgba(26,26,26,.7)),url('../images/hero-snow-mountain.webp') center/cover no-repeat;background-attachment:fixed}
.hero-inner{max-width:900px;padding:120px 20px 60px}
.hero h1{color:#fff;text-shadow:0 4px 20px rgba(0,0,0,.4)}
.hero .lead{font-size:1.2rem;margin:1.4rem 0 2rem;color:#f0f0f0;font-family:"Caveat",cursive;font-style:italic;font-size:1.6rem}
.cta-group{display:flex;gap:14px;justify-content:center;flex-wrap:wrap}
.btn{display:inline-block;padding:14px 30px;border-radius:6px;font-weight:700;font-size:1rem;cursor:pointer;border:0;transition:all .25s;letter-spacing:1px}
.btn-primary{background:var(--secondary);color:#fff}
.btn-primary:hover{background:var(--accent);color:#fff;transform:translateY(-2px);box-shadow:0 8px 20px rgba(255,109,0,.4)}
.btn-outline{background:transparent;color:#fff;border:2px solid #fff}
.btn-outline:hover{background:#fff;color:var(--primary)}
.scroll-hint{position:absolute;bottom:30px;left:50%;transform:translateX(-50%);color:#fff;font-size:.85rem;animation:bounce 2s infinite}
@keyframes bounce{0%,100%{transform:translateX(-50%) translateY(0)}50%{transform:translateX(-50%) translateY(8px)}}

/* Sections */
section.block{padding:80px 0}
.section-title{text-align:center;margin-bottom:50px}
.section-title h2::after{content:"";display:block;width:60px;height:4px;background:var(--secondary);margin:14px auto 0}
.section-title .sub{color:var(--muted);font-size:1rem;margin-top:8px}

/* Card Grid */
.grid{display:grid;gap:24px}
.grid-3{grid-template-columns:repeat(auto-fit,minmax(280px,1fr))}
.grid-2{grid-template-columns:repeat(auto-fit,minmax(340px,1fr))}
.card{background:var(--card-bg);border-radius:var(--radius);overflow:hidden;box-shadow:var(--shadow);transition:transform .3s,box-shadow .3s;display:flex;flex-direction:column}
.card:hover{transform:translateY(-6px);box-shadow:0 14px 32px rgba(0,0,0,.14)}
.card-img{position:relative;overflow:hidden;aspect-ratio:16/10}
.card-img img{width:100%;height:100%;object-fit:cover;transition:transform .5s}
.card:hover .card-img img{transform:scale(1.08)}
.card-img .overlay{position:absolute;inset:0;background:linear-gradient(transparent,rgba(0,0,0,.7));display:flex;align-items:flex-end;padding:14px;color:#fff;opacity:0;transition:opacity .3s;font-size:.85rem}
.card:hover .overlay{opacity:1}
.card-body{padding:20px;flex:1;display:flex;flex-direction:column}
.card-body h3{color:var(--primary);margin-bottom:8px}
.tag{display:inline-block;background:var(--secondary);color:#fff;font-size:.75rem;padding:3px 10px;border-radius:20px;margin-right:6px;font-weight:600}
.tag.alt{background:var(--primary)}
.difficulty{color:var(--accent);font-weight:700;letter-spacing:2px}
.meta{display:flex;justify-content:space-between;align-items:center;margin-top:auto;padding-top:14px;color:var(--muted);font-size:.85rem}

/* Timeline */
.timeline{position:relative;padding-left:40px;max-width:800px;margin:0 auto}
.timeline::before{content:"";position:absolute;left:14px;top:0;bottom:0;width:3px;background:linear-gradient(var(--secondary),var(--accent))}
.tl-item{position:relative;margin-bottom:40px;background:#fff;padding:22px;border-radius:var(--radius);box-shadow:var(--shadow)}
.tl-item::before{content:"";position:absolute;left:-32px;top:24px;width:14px;height:14px;border-radius:50%;background:var(--secondary);border:3px solid #fff;box-shadow:0 0 0 2px var(--secondary)}
.tl-date{color:var(--secondary);font-weight:700;font-size:.9rem;margin-bottom:6px}

/* Weather Widget */
.weather-widget{background:linear-gradient(135deg,var(--primary),#263238);color:#fff;border-radius:var(--radius);padding:30px;display:grid;grid-template-columns:repeat(auto-fit,minmax(150px,1fr));gap:20px;box-shadow:var(--shadow)}
.weather-item{text-align:center}
.weather-item .val{font-size:2rem;font-weight:800;color:var(--accent);font-family:"Montserrat",sans-serif}
.weather-item .lbl{font-size:.85rem;opacity:.8;margin-top:4px}
.weather-alert{background:var(--secondary);color:#fff;padding:12px 18px;border-radius:6px;margin-top:20px;font-weight:600;text-align:center}

/* Accordion */
.accordion-item{background:#fff;border-radius:8px;margin-bottom:10px;box-shadow:0 2px 8px rgba(0,0,0,.06);overflow:hidden}
.accordion-head{padding:16px 22px;font-weight:700;color:var(--primary);cursor:pointer;display:flex;justify-content:space-between;align-items:center;background:#fff;user-select:none}
.accordion-head:hover{background:#f5f5f5}
.accordion-head::after{content:"+";font-size:1.4rem;color:var(--secondary);transition:transform .3s}
.accordion-item.open .accordion-head::after{content:"−"}
.accordion-body{max-height:0;overflow:hidden;transition:max-height .35s ease;padding:0 22px}
.accordion-item.open .accordion-body{max-height:1000px;padding:14px 22px 20px}

/* Elevation chart */
.elev-chart{background:#fff;padding:24px;border-radius:var(--radius);box-shadow:var(--shadow)}
.elev-svg{width:100%;height:220px}

/* Map placeholder */
.map-box{background:linear-gradient(135deg,#37474F,#546e7a);height:380px;border-radius:var(--radius);position:relative;overflow:hidden;box-shadow:var(--shadow);color:#fff;display:flex;align-items:center;justify-content:center;background-image:url('../images/route-tibet.webp');background-size:cover;background-position:center}
.map-box::before{content:"";position:absolute;inset:0;background:rgba(55,71,79,.55)}
.map-box .map-pin{position:absolute;color:var(--secondary);font-size:2rem;text-shadow:0 2px 6px rgba(0,0,0,.6);z-index:2}

/* Sponsors */
.logo-wall{display:flex;flex-wrap:wrap;justify-content:center;gap:40px;align-items:center;padding:20px 0}
.logo-wall .logo{font-family:"Oswald",sans-serif;font-size:1.4rem;color:#9aa0a6;filter:grayscale(1);font-weight:700;letter-spacing:2px;transition:filter .3s,color .3s}
.logo-wall .logo:hover{filter:grayscale(0);color:var(--secondary)}

/* Newsletter */
.newsletter{background:linear-gradient(135deg,var(--primary),#1c2429);color:#fff;border-radius:var(--radius);padding:40px;text-align:center}
.newsletter h2{color:#fff}
.newsletter form{display:flex;gap:10px;max-width:480px;margin:20px auto 0;flex-wrap:wrap;justify-content:center}
.newsletter input{flex:1;min-width:200px;padding:14px 18px;border:0;border-radius:6px;font-size:1rem}

/* Footer */
.site-footer{background:var(--primary);color:#bdc1c6;padding:60px 0 20px;margin-top:60px}
.footer-grid{display:grid;grid-template-columns:repeat(auto-fit,minmax(200px,1fr));gap:30px}
.footer-col h4{color:#fff;font-size:1rem;margin-bottom:14px;letter-spacing:1px}
.footer-col ul{list-style:none}
.footer-col li{margin-bottom:8px}
.footer-col a{color:#bdc1c6}
.footer-col a:hover{color:var(--secondary)}
.footer-bottom{border-top:1px solid rgba(255,255,255,.1);margin-top:40px;padding-top:20px;text-align:center;font-size:.85rem;color:#90949c}

/* Page header */
.page-hero{padding:160px 0 60px;background:linear-gradient(135deg,var(--primary),#263238);color:#fff;text-align:center}
.page-hero h1{color:#fff}
.page-hero p{color:#cfd2d6;max-width:700px;margin:14px auto 0}
.breadcrumb{font-size:.85rem;color:#cfd2d6;margin-top:12px}
.breadcrumb a{color:var(--accent)}

/* Article */
article.content{background:#fff;padding:40px;border-radius:var(--radius);box-shadow:var(--shadow);max-width:880px;margin:40px auto}
article.content h2{margin-top:24px}
article.content h3{margin-top:18px;color:var(--primary)}
article.content p{margin-bottom:14px}
article.content ul,article.content ol{margin:0 0 16px 22px}
article.content blockquote{border-left:4px solid var(--secondary);padding:10px 18px;background:#fff8f0;font-family:"Caveat",cursive;font-size:1.3rem;color:#5a3b00;margin:18px 0}
article.content img{border-radius:8px;margin:18px 0}

/* Risk warning */
.risk-warn{background:#fff3e0;border-left:5px solid var(--secondary);padding:18px 22px;border-radius:6px;margin:24px 0;color:#5a3b00}
.risk-warn strong{color:var(--secondary);display:block;margin-bottom:6px}

/* Forum */
.forum-list{list-style:none}
.forum-item{display:flex;justify-content:space-between;align-items:center;background:#fff;padding:18px 22px;margin-bottom:10px;border-radius:8px;box-shadow:0 2px 8px rgba(0,0,0,.05);transition:transform .2s}
.forum-item:hover{transform:translateX(4px);border-left:4px solid var(--secondary)}
.forum-meta{color:var(--muted);font-size:.85rem;text-align:right;min-width:120px}

/* Search */
.search-wrap{max-width:700px;margin:30px auto}
.search-form{display:flex;gap:8px}
.search-form input{flex:1;padding:14px 20px;border:2px solid var(--border);border-radius:6px;font-size:1rem}
.search-form input:focus{outline:none;border-color:var(--secondary)}
.filter-row{display:flex;gap:10px;flex-wrap:wrap;justify-content:center;margin-top:14px}
.filter-row select{padding:10px 14px;border:1px solid var(--border);border-radius:6px;background:#fff}

/* Loader */
.loader{position:fixed;inset:0;background:var(--bg);display:flex;align-items:center;justify-content:center;z-index:9999;transition:opacity .4s}
.loader.hidden{opacity:0;pointer-events:none}
.compass{width:64px;height:64px;border:4px solid var(--primary);border-top-color:var(--secondary);border-radius:50%;animation:spin 1.2s linear infinite}
@keyframes spin{to{transform:rotate(360deg)}}

/* Reveal on scroll */
.reveal{opacity:0;transform:translateY(30px);transition:opacity .8s,transform .8s}
.reveal.in{opacity:1;transform:translateY(0)}

/* QR code */
.qr-row{display:flex;justify-content:center;gap:40px;flex-wrap:wrap;margin-top:30px}
.qr-box{background:#fff;padding:20px;border-radius:var(--radius);box-shadow:var(--shadow);text-align:center}
.qr-img{width:160px;height:160px;background:repeating-linear-gradient(45deg,#000,#000 4px,#fff 4px,#fff 8px);border-radius:6px}

/* Utility */
.text-center{text-align:center}
.mt-4{margin-top:1.5rem}
.checklist{list-style:none}
.checklist li{padding:8px 0;border-bottom:1px solid var(--border);display:flex;align-items:center;gap:10px}
.checklist input[type=checkbox]{width:18px;height:18px;accent-color:var(--secondary)}