/* ============ 首页 Hero ============ */
.hero{position:relative;min-height:620px;display:flex;align-items:center;overflow:hidden;background:#080d18;color:#fff;isolation:isolate;}
.hero-bg{position:absolute;inset:0;z-index:-2;background:radial-gradient(900px 520px at 78% 22%,rgba(91,95,199,.60),transparent 62%),radial-gradient(760px 520px at 62% 96%,rgba(0,183,195,.34),transparent 62%),radial-gradient(680px 420px at 12% 6%,rgba(0,103,184,.55),transparent 62%),linear-gradient(135deg,#070b14 0%,#121b34 52%,#080d18 100%);}
.hero-bg::after{content:"";position:absolute;inset:0;background-image:linear-gradient(rgba(255,255,255,.055) 1px,transparent 1px),linear-gradient(90deg,rgba(255,255,255,.055) 1px,transparent 1px);background-size:52px 52px;-webkit-mask-image:radial-gradient(circle at 72% 42%,#000 0%,transparent 72%);mask-image:radial-gradient(circle at 72% 42%,#000 0%,transparent 72%);}
.hero-glow{position:absolute;width:640px;height:640px;right:6%;top:50%;transform:translateY(-50%);background:radial-gradient(circle,rgba(0,183,195,.30),transparent 62%);filter:blur(30px);z-index:-1;animation:breathe 9s ease-in-out infinite;}
@keyframes breathe{0%,100%{opacity:.65;transform:translateY(-50%) scale(1);}50%{opacity:1;transform:translateY(-50%) scale(1.09);}}
.hero-blocks{position:absolute;inset:0;z-index:-1;pointer-events:none;}
.hb{position:absolute;border-radius:8px;box-shadow:0 18px 40px rgba(0,0,0,.42),inset 0 1px 0 rgba(255,255,255,.28);opacity:.9;}
.hb::after{content:"";position:absolute;inset:0;border-radius:8px;background:linear-gradient(160deg,rgba(255,255,255,.34),transparent 55%);}
.hb1{width:96px;height:96px;right:22%;top:16%;background:linear-gradient(140deg,#5b5fc7,#3b3fa0);animation:float1 8s ease-in-out infinite;}
.hb2{width:64px;height:64px;right:11%;top:52%;background:linear-gradient(140deg,#00b7c3,#00838f);animation:float2 7s ease-in-out infinite;}
.hb3{width:76px;height:76px;right:32%;top:64%;background:linear-gradient(140deg,#0067b8,#004b86);animation:float3 9.5s ease-in-out infinite;}
.hb4{width:46px;height:46px;right:44%;top:26%;background:linear-gradient(140deg,#ff8c00,#c96a00);animation:float2 6.4s ease-in-out infinite;}
.hb5{width:34px;height:34px;right:8%;top:26%;background:linear-gradient(140deg,#ff5f7e,#c93a56);animation:float1 7.6s ease-in-out infinite;}
@keyframes float1{0%,100%{transform:translateY(0) rotate(0deg);}50%{transform:translateY(-22px) rotate(6deg);}}
@keyframes float2{0%,100%{transform:translateY(0) rotate(0deg);}50%{transform:translateY(18px) rotate(-7deg);}}
@keyframes float3{0%,100%{transform:translateY(0) rotate(0deg);}50%{transform:translateY(-16px) rotate(-4deg);}}
.hero-content{position:relative;z-index:2;width:100%;padding:96px 0;}
.hero-inner{max-width:720px;}
.eyebrow{display:inline-flex;align-items:center;gap:8px;font-size:12.5px;font-weight:600;letter-spacing:.06em;text-transform:uppercase;color:#8fd6ff;background:rgba(0,183,195,.12);border:1px solid rgba(143,214,255,.28);padding:6px 14px;border-radius:100px;margin-bottom:26px;backdrop-filter:blur(6px);}
.eyebrow .dot{width:6px;height:6px;border-radius:50%;background:#00e0c6;box-shadow:0 0 10px #00e0c6;animation:pulse 2s infinite;}
@keyframes pulse{0%,100%{opacity:1;}50%{opacity:.35;}}
.hero h1{font-size:clamp(2.2rem,5.2vw,3.9rem);font-weight:600;line-height:1.1;letter-spacing:-.025em;margin-bottom:22px;}
.hero h1 .grad{background:linear-gradient(100deg,#00e0c6 0%,#6ea8ff 45%,#b98cff 100%);-webkit-background-clip:text;background-clip:text;color:transparent;}
.hero p{font-size:clamp(1rem,1.4vw,1.15rem);line-height:1.65;color:rgba(255,255,255,.80);max-width:600px;margin-bottom:38px;}
.hero-actions{display:flex;flex-wrap:wrap;gap:14px;align-items:center;}

/* ============ 卡片 ============ */
.card{background:#fff;border:1px solid var(--line);border-radius:8px;overflow:hidden;display:flex;flex-direction:column;transition:transform .28s cubic-bezier(.2,.7,.3,1),box-shadow .28s,border-color .28s;}
.card:hover{transform:translateY(-6px);box-shadow:0 16px 40px rgba(0,0,0,.13);border-color:transparent;}
.card-visual{position:relative;height:170px;overflow:hidden;display:flex;align-items:center;justify-content:center;}
.card-visual::after{content:"";position:absolute;inset:0;background-image:linear-gradient(rgba(255,255,255,.10) 1px,transparent 1px),linear-gradient(90deg,rgba(255,255,255,.10) 1px,transparent 1px);background-size:30px 30px;}
.v-blue{background:linear-gradient(140deg,#0067b8,#00a0e9);}
.v-cyan{background:linear-gradient(140deg,#00a5b5,#00d4c0);}
.v-violet{background:linear-gradient(140deg,#5b5fc7,#8a6bff);}
.v-orange{background:linear-gradient(140deg,#e8730c,#ffb02e);}
.card-visual svg{position:relative;z-index:2;width:56px;height:56px;stroke:#fff;opacity:.96;}
.card-body{padding:22px 22px 24px;display:flex;flex-direction:column;flex:1;}
.card-body h3{font-size:1.05rem;font-weight:600;margin-bottom:9px;letter-spacing:-.01em;}
.card-body p{font-size:13.8px;line-height:1.65;color:var(--gray);flex:1;margin-bottom:16px;}
.card-body .link-more{font-size:13.5px;}

/* ============ Feature ============ */
.feature{position:relative;overflow:hidden;border-radius:10px;padding:46px 42px;min-height:310px;display:flex;flex-direction:column;justify-content:flex-end;color:#fff;transition:transform .3s cubic-bezier(.2,.7,.3,1),box-shadow .3s;}
.feature:hover{transform:translateY(-6px);box-shadow:0 20px 48px rgba(0,0,0,.24);}
.feature::before{content:"";position:absolute;inset:0;background-image:linear-gradient(rgba(255,255,255,.09) 1px,transparent 1px),linear-gradient(90deg,rgba(255,255,255,.09) 1px,transparent 1px);background-size:40px 40px;-webkit-mask-image:radial-gradient(circle at 78% 22%,#000,transparent 70%);mask-image:radial-gradient(circle at 78% 22%,#000,transparent 70%);}
.feature-fx{position:absolute;width:280px;height:280px;border-radius:50%;right:-60px;top:-70px;filter:blur(12px);opacity:.5;}
.f-blue{background:linear-gradient(135deg,#0b3d63,#0067b8 55%,#5b5fc7);}
.f-violet{background:linear-gradient(135deg,#26265c,#5b5fc7 55%,#00b7c3);}
.f-blue .feature-fx{background:radial-gradient(circle,rgba(0,224,198,.55),transparent 68%);}
.f-violet .feature-fx{background:radial-gradient(circle,rgba(185,140,255,.55),transparent 68%);}
.feature h3{position:relative;font-size:clamp(1.3rem,2.2vw,1.7rem);font-weight:600;margin-bottom:12px;letter-spacing:-.02em;}
.feature p{position:relative;font-size:14.5px;line-height:1.65;color:rgba(255,255,255,.85);max-width:460px;margin-bottom:22px;}
.feature .tagline{position:relative;display:inline-block;font-size:11.5px;font-weight:700;letter-spacing:.1em;text-transform:uppercase;color:rgba(255,255,255,.72);margin-bottom:12px;}
.feature .btn{position:relative;align-self:flex-start;padding:10px 22px;font-size:13.5px;background:#fff;color:#0b0b0b;box-shadow:none;}
.feature .btn:hover{background:rgba(255,255,255,.86);}

/* ============ Stats ============ */
.stats{background:var(--soft);border-top:1px solid var(--line);border-bottom:1px solid var(--line);}
.stats-inner{max-width:1600px;margin:0 auto;padding:56px 24px;display:grid;grid-template-columns:repeat(4,1fr);gap:32px;text-align:center;}
.stat-num{font-size:clamp(1.9rem,3.4vw,2.6rem);font-weight:600;letter-spacing:-.03em;background:linear-gradient(120deg,#0067b8,#5b5fc7 60%,#00b7c3);-webkit-background-clip:text;background-clip:text;color:transparent;line-height:1.1;margin-bottom:8px;}
.stat-label{font-size:13.5px;color:var(--gray);}

/* ============ CTA ============ */
.cta-band{position:relative;overflow:hidden;background:linear-gradient(120deg,#0a1424 0%,#16264a 48%,#0a1424 100%);color:#fff;text-align:center;}
.cta-band::before{content:"";position:absolute;inset:0;background:radial-gradient(600px 300px at 22% 20%,rgba(0,183,195,.30),transparent 65%),radial-gradient(600px 300px at 80% 80%,rgba(91,95,199,.34),transparent 65%);}
.cta-inner{position:relative;max-width:820px;margin:0 auto;padding:84px 24px;}
.cta-inner h2{font-size:clamp(1.7rem,3.4vw,2.5rem);font-weight:600;letter-spacing:-.025em;margin-bottom:16px;}
.cta-inner p{font-size:15.5px;line-height:1.7;color:rgba(255,255,255,.78);margin-bottom:34px;}
.cta-actions{display:flex;justify-content:center;flex-wrap:wrap;gap:14px;}

/* ============ 社区预览卡片（首页用） ============ */
#communityGrid{transition:opacity .4s ease;}
#communityGrid.fading{opacity:0;}
.comm-card{background:#fff;border:1px solid var(--line);border-radius:12px;overflow:hidden;display:flex;flex-direction:column;transition:transform .28s cubic-bezier(.2,.7,.3,1),box-shadow .28s,border-color .28s;cursor:pointer;}
.comm-card:hover{transform:translateY(-6px);box-shadow:0 16px 40px rgba(0,0,0,.13);border-color:transparent;}
.comm-cover{position:relative;height:190px;overflow:hidden;background-size:cover;background-position:center;display:flex;align-items:center;justify-content:center;}
.comm-cover::after{content:"";position:absolute;inset:0;background-image:linear-gradient(rgba(255,255,255,.10) 1px,transparent 1px),linear-gradient(90deg,rgba(255,255,255,.10) 1px,transparent 1px);background-size:30px 30px;}
.comm-cover .big-initial{position:relative;z-index:1;font-size:64px;font-weight:700;color:rgba(255,255,255,.92);text-shadow:0 4px 12px rgba(0,0,0,.15);}
.comm-type-badge{position:absolute;top:10px;left:10px;z-index:2;display:inline-flex;align-items:center;gap:4px;padding:4px 10px;border-radius:100px;font-size:11px;font-weight:600;background:rgba(255,255,255,.94);color:var(--blue);backdrop-filter:blur(8px);box-shadow:0 2px 8px rgba(0,0,0,.1);}
.comm-type-badge.embedded{color:#107c10;}
.comm-type-badge svg{width:11px;height:11px;}
.comm-body{padding:20px 20px 22px;display:flex;flex-direction:column;flex:1;}
.comm-body h3{font-size:1.05rem;font-weight:600;margin-bottom:8px;letter-spacing:-.01em;overflow:hidden;display:-webkit-box;-webkit-line-clamp:2;-webkit-box-orient:vertical;}
.comm-body p{font-size:13.5px;line-height:1.6;color:var(--gray);flex:1;margin-bottom:14px;overflow:hidden;display:-webkit-box;-webkit-line-clamp:2;-webkit-box-orient:vertical;}
.comm-meta{display:flex;align-items:center;justify-content:space-between;gap:12px;padding-top:12px;border-top:1px solid var(--line);font-size:12px;color:var(--gray-2);}
.comm-meta .open{display:inline-flex;align-items:center;gap:4px;font-size:12.5px;font-weight:600;color:var(--blue);cursor:pointer;}
.comm-meta .open:hover{text-decoration:underline;}
.comm-meta .open svg{width:11px;height:11px;}
.comm-author{display:inline-flex;align-items:center;gap:6px;font-size:12px;color:var(--gray-2);transition:color .15s;cursor:pointer;}
.comm-author:hover{color:var(--blue);}
.comm-author-avatar{width:20px;height:20px;border-radius:50%;display:grid;place-items:center;background:linear-gradient(135deg,#4a9eff,#0067c0);color:#fff;font-size:10px;font-weight:700;flex-shrink:0;}

/* ============ 路由页面（论坛 / 社区） ============ */
.route-page{min-height:calc(100vh - var(--nav-h));background:#f8f9fb;}
.route-hero{max-width:1600px;margin:0 auto;padding:60px 24px 20px;}
.route-badge{display:inline-flex;align-items:center;gap:7px;font-size:11.5px;font-weight:700;letter-spacing:.1em;text-transform:uppercase;color:var(--blue);background:rgba(0,103,184,.09);border:1px solid rgba(0,103,184,.22);padding:5px 13px;border-radius:100px;margin-bottom:18px;}
.route-hero h1{font-size:clamp(2rem,4.4vw,3.2rem);font-weight:600;letter-spacing:-.03em;line-height:1.06;margin-bottom:14px;}
.route-hero h1 .grad{background:linear-gradient(100deg,#0067b8 0%,#5b5fc7 52%,#00b7c3 100%);-webkit-background-clip:text;background-clip:text;color:transparent;}
.route-hero p{font-size:clamp(1rem,1.5vw,1.14rem);line-height:1.7;color:var(--gray);max-width:640px;}
.route-main{max-width:1600px;margin:0 auto;padding:24px 24px 100px;}
.route-count{font-size:13px;color:var(--gray-2);margin-bottom:18px;}
.route-toolbar{display:flex;align-items:center;justify-content:space-between;gap:16px;margin-bottom:20px;flex-wrap:wrap;}
.route-sort{display:inline-flex;gap:4px;padding:4px;background:#fff;border:1px solid var(--line);border-radius:9px;}
.route-sort button{padding:7px 14px;border-radius:6px;font-size:12.5px;font-weight:600;color:var(--gray);transition:background .15s,color .15s;}
.route-sort button:hover{background:var(--soft);color:var(--ink);}
.route-sort button.on{background:var(--blue);color:#fff;}
.route-back-btn{display:inline-flex;align-items:center;gap:6px;padding:8px 16px;border-radius:6px;background:#fff;border:1px solid var(--line);font-size:13px;font-weight:600;color:var(--ink);transition:background .15s,border-color .15s;}
.route-back-btn:hover{background:var(--soft);border-color:#c8c8c8;}
.route-back-btn svg{width:14px;height:14px;}

.forum-grid{display:grid;grid-template-columns:1fr;gap:14px;}
.forum-card{display:flex;align-items:flex-start;gap:18px;background:#fff;border:1px solid var(--line);border-radius:12px;padding:20px 24px;cursor:pointer;color:inherit;text-decoration:none;transition:transform .2s,box-shadow .2s,border-color .2s;}
.forum-card:hover{transform:translateY(-3px);box-shadow:0 12px 30px rgba(0,0,0,.08);border-color:transparent;}
.forum-card-avatar{width:52px;height:52px;border-radius:50%;display:grid;place-items:center;background:linear-gradient(135deg,#4a9eff,#0067c0);color:#fff;font-size:20px;font-weight:700;flex-shrink:0;cursor:pointer;transition:transform .18s,box-shadow .18s;}
.forum-card-avatar:hover{transform:scale(1.06);box-shadow:0 4px 14px rgba(0,103,184,.35);}
.forum-card-content{flex:1;min-width:0;}
.forum-card-title{font-size:17px;font-weight:600;color:var(--ink);margin-bottom:8px;line-height:1.4;overflow:hidden;display:-webkit-box;-webkit-line-clamp:2;-webkit-box-orient:vertical;}
.forum-card-desc{font-size:13.5px;color:var(--gray);line-height:1.7;overflow:hidden;display:-webkit-box;-webkit-line-clamp:3;-webkit-box-orient:vertical;}
.forum-card-meta{flex-shrink:0;font-size:12.5px;color:var(--gray-2);white-space:nowrap;}
.forum-card-thumb{width:140px;height:96px;border-radius:10px;background-size:cover;background-position:center;flex-shrink:0;border:1px solid var(--line);}

.work-page-grid{display:grid;grid-template-columns:repeat(auto-fill,minmax(280px,1fr));gap:22px;}
.work-page-card{background:#fff;border:1px solid var(--line);border-radius:12px;overflow:hidden;display:flex;flex-direction:column;transition:transform .25s,box-shadow .25s;color:inherit;text-decoration:none;cursor:pointer;}
.work-page-card:hover{transform:translateY(-5px);box-shadow:0 16px 40px rgba(0,0,0,.12);border-color:transparent;}
.work-page-cover{position:relative;height:180px;background-size:cover;background-position:center;display:flex;align-items:center;justify-content:center;background-color:#0067b8;}
.work-page-cover .big-initial{position:relative;z-index:1;font-size:56px;font-weight:700;color:rgba(255,255,255,.92);text-shadow:0 4px 12px rgba(0,0,0,.15);}
.work-page-cover::after{content:"";position:absolute;inset:0;background-image:linear-gradient(rgba(255,255,255,.08) 1px,transparent 1px),linear-gradient(90deg,rgba(255,255,255,.08) 1px,transparent 1px);background-size:28px 28px;}
.work-page-body{padding:18px 20px 20px;display:flex;flex-direction:column;flex:1;}
.work-page-body h3{font-size:15px;font-weight:600;margin-bottom:8px;line-height:1.35;overflow:hidden;display:-webkit-box;-webkit-line-clamp:2;-webkit-box-orient:vertical;}
.work-page-body p{font-size:13px;line-height:1.65;color:var(--gray);flex:1;margin-bottom:14px;overflow:hidden;display:-webkit-box;-webkit-line-clamp:3;-webkit-box-orient:vertical;}
.work-page-meta{display:flex;align-items:center;justify-content:space-between;gap:12px;padding-top:12px;border-top:1px solid var(--line);font-size:12px;color:var(--gray-2);}
.work-page-meta .open{display:inline-flex;align-items:center;gap:4px;font-size:12.5px;font-weight:600;color:var(--blue);}
.work-page-meta .open:hover{text-decoration:underline;}
.work-page-meta .open svg{width:11px;height:11px;}
.wp-author{display:inline-flex;align-items:center;gap:5px;cursor:pointer;transition:color .15s;}
.wp-author:hover{color:var(--blue);}
.wp-author-avatar{width:18px;height:18px;border-radius:50%;display:grid;place-items:center;background:linear-gradient(135deg,#4a9eff,#0067c0);color:#fff;font-size:9px;font-weight:700;flex-shrink:0;}

.empty-route{padding:80px 30px;text-align:center;color:var(--gray-2);background:#fff;border:1px dashed var(--line);border-radius:14px;}
.empty-route svg{width:64px;height:64px;margin:0 auto 20px;opacity:.35;stroke:var(--gray);}
.empty-route h3{font-size:16px;font-weight:600;color:var(--ink);margin-bottom:8px;}
.empty-route p{font-size:13.5px;}

/* ============ LiuOS 页面 ============ */
.liuos-page{min-height:100vh;background:#f8f9fb;display:flex;flex-direction:column;}
.liuos-nav{position:sticky;top:0;z-index:100;background:rgba(255,255,255,.92);backdrop-filter:blur(14px);border-bottom:1px solid var(--line);height:56px;display:flex;align-items:center;justify-content:space-between;padding:0 24px;}
.liuos-nav-brand{display:flex;align-items:center;gap:10px;font-size:14px;font-weight:700;}
.liuos-nav-brand img{height:28px;width:auto;max-width:120px;object-fit:contain;}
.liuos-nav-back{display:inline-flex;align-items:center;gap:6px;font-size:13.5px;font-weight:600;color:var(--blue);padding:8px 14px;border-radius:4px;transition:background .15s;}
.liuos-nav-back:hover{background:rgba(0,103,184,.08);}
.liuos-main{flex:1;max-width:1400px;width:100%;margin:0 auto;padding:56px 24px 80px;}
.liuos-hero{max-width:720px;margin-bottom:48px;}
.liuos-badge-sm{display:inline-flex;align-items:center;gap:7px;font-size:11.5px;font-weight:700;letter-spacing:.1em;text-transform:uppercase;color:var(--blue);background:rgba(0,103,184,.09);border:1px solid rgba(0,103,184,.22);padding:5px 13px;border-radius:100px;margin-bottom:18px;}
.liuos-hero h1{font-size:clamp(2.2rem,4.6vw,3.4rem);font-weight:600;letter-spacing:-.03em;line-height:1.06;margin-bottom:16px;}
.liuos-hero h1 .grad{background:linear-gradient(100deg,#0067b8 0%,#5b5fc7 52%,#00b7c3 100%);-webkit-background-clip:text;background-clip:text;color:transparent;}
.liuos-hero p{font-size:clamp(1rem,1.5vw,1.14rem);line-height:1.7;color:var(--gray);}
.liuos-versions{display:flex;flex-direction:column;gap:20px;}
.liuos-version-item{display:grid;grid-template-columns:minmax(240px,1fr) 280px 240px;gap:32px;align-items:center;background:#fff;border:1px solid var(--line);border-radius:12px;padding:24px 28px;color:inherit;text-decoration:none;transition:transform .3s cubic-bezier(.2,.7,.3,1),box-shadow .3s,border-color .3s;}
.liuos-version-item:hover{transform:translateY(-6px);box-shadow:0 16px 40px rgba(0,0,0,.13);border-color:transparent;}
.liuos-version-item.archive{opacity:.72;}
.liuos-version-item.archive:hover{opacity:1;}
.liuos-version-info h3{font-size:1.2rem;font-weight:600;margin-bottom:9px;color:var(--ink);}
.liuos-version-info p{font-size:13.5px;line-height:1.65;color:var(--gray);}
.liuos-version-info .tag-new{display:inline-block;font-size:11px;font-weight:700;color:var(--blue);background:rgba(0,103,184,.08);padding:3px 9px;border-radius:100px;margin-left:8px;vertical-align:2px;}
.liuos-tag-archive{display:inline-block;font-size:10.5px;font-weight:700;color:var(--gray-2);background:rgba(0,0,0,.06);padding:3px 9px;border-radius:100px;margin-left:8px;vertical-align:2px;}
.liuos-version-preview{width:100%;aspect-ratio:16/10;border-radius:10px;overflow:hidden;background:#f0f0f0;box-shadow:0 1px 3px rgba(0,0,0,.06);display:flex;align-items:center;justify-content:center;}
.liuos-version-preview img{width:100%;height:100%;object-fit:cover;display:block;}
.liuos-version-preview .liuos-placeholder{display:flex;align-items:center;justify-content:center;width:100%;height:100%;font-weight:700;font-size:1.6rem;letter-spacing:-.02em;color:#fff;background:linear-gradient(135deg,#0067b8,#00a0e9);}
.liuos-version-item.archive .liuos-placeholder{background:#e8eaed;color:#8b8b8b;font-size:1.4rem;}
.liuos-version-action{display:flex;flex-direction:column;gap:8px;}
.liuos-version-btn{display:inline-flex;align-items:center;justify-content:center;gap:8px;padding:12px 22px;background:var(--blue);color:#fff;border-radius:6px;font-size:13.5px;font-weight:600;white-space:nowrap;box-shadow:0 4px 12px rgba(0,103,184,.24);transition:background .2s,transform .2s;}
.liuos-version-item:hover .liuos-version-btn{background:var(--blue-d);transform:translateY(-2px);}
.liuos-version-btn svg{width:15px;height:15px;transition:transform .2s;}
.liuos-version-btn.secondary{background:#fff;color:var(--blue);border:1px solid rgba(0,103,184,.35);box-shadow:none;}
.liuos-version-btn.secondary:hover{background:rgba(0,103,184,.06);}
.liuos-version-item:hover .liuos-version-btn.secondary{background:rgba(0,103,184,.08);transform:translateY(-2px);}
.liuos-archive-title{font-size:14px;font-weight:600;color:var(--gray-2);margin:36px 0 16px;padding:0 2px;}

/* ============ 回到顶部 ============ */
.to-top{position:fixed;right:26px;bottom:26px;z-index:150;width:44px;height:44px;border-radius:50%;background:var(--blue);color:#fff;display:flex;align-items:center;justify-content:center;box-shadow:0 8px 24px rgba(0,103,184,.4);opacity:0;visibility:hidden;transform:translateY(12px);transition:opacity .25s,transform .25s,visibility .25s,background .18s;}
.to-top.show{opacity:1;visibility:visible;transform:translateY(0);}
.to-top:hover{background:var(--blue-d);}

/* ============ 响应式 ============ */
@media (max-width:980px){
  .hero{min-height:520px;}
  .hero-content{padding:72px 0;}
  .hero-blocks{opacity:.5;}
  .stats-inner{grid-template-columns:repeat(2,1fr);gap:36px 20px;}
  .liuos-version-item{grid-template-columns:1fr;gap:18px;padding:22px;}
  .liuos-version-action{flex-direction:row;}
  .liuos-version-action .liuos-version-btn{flex:1;}
  .forum-card-thumb{display:none;}
}
@media (max-width:640px){
  .feature{padding:34px 26px;min-height:270px;}
  .hero-blocks{display:none;}
  .to-top{right:16px;bottom:16px;}
  .liuos-main{padding:36px 18px 60px;}
  .liuos-nav{padding:0 16px;}
  .liuos-version-preview{aspect-ratio:16/9;}
  .route-hero{padding:36px 18px 8px;}
  .route-main{padding:16px 18px 60px;}
  .forum-card{padding:16px;gap:12px;}
  .forum-card-avatar{width:42px;height:42px;font-size:16px;}
  .forum-card-title{font-size:15px;}
  .forum-card-desc{font-size:13px;-webkit-line-clamp:2;}
  .work-page-grid{grid-template-columns:1fr;}
}