/* ================================================================
   google1 — Polar Ice / Arctic Blue Theme
   Light frosted surfaces + ice blue accents + navy depth
   ================================================================ */
*,*::before,*::after{box-sizing:border-box;margin:0;padding:0}
html{scroll-behavior:smooth;font-size:16px}
body{
  font-family:"Segoe UI","PingFang SC","Microsoft YaHei",system-ui,sans-serif;
  color:#1e293b;background:#f0f7ff;line-height:1.75;
  -webkit-font-smoothing:antialiased;overflow-x:hidden;
}
a{color:inherit;text-decoration:none}
button{cursor:pointer;font-family:inherit;border:none}
ul,ol{list-style:none}

@keyframes spin{from{transform:rotate(0)}to{transform:rotate(360deg)}}
@keyframes fadeIn{from{opacity:0;transform:translateY(24px)}to{opacity:1;transform:translateY(0)}}
@keyframes drift{0%,100%{transform:translateY(0) rotate(0)}50%{transform:translateY(-12px) rotate(2deg)}}
@keyframes pulse{0%,100%{opacity:.5}50%{opacity:1}}
@keyframes ripple{0%{box-shadow:0 0 0 0 rgba(14,165,233,.35)}100%{box-shadow:0 0 0 28px rgba(14,165,233,0)}}

:root{
  --ice:#0ea5e9;
  --ice-light:#7dd3fc;
  --ice-pale:#e0f2fe;
  --navy:#0f172a;
  --navy2:#1e293b;
  --slate:#475569;
  --slate2:#64748b;
  --surface:#ffffff;
  --surface2:#f8fafc;
  --bg:#f0f7ff;
  --border:rgba(14,165,233,.15);
  --border2:#e2e8f0;
  --shadow:0 4px 20px rgba(14,165,233,.08);
  --shadow2:0 8px 32px rgba(14,165,233,.12);
  --shadow3:0 1px 3px rgba(0,0,0,.06);
  --radius:14px;
  --radius2:20px;
  --max-w:1160px;
}

/* ============ LAYOUT ============ */
.wrap{max-width:var(--max-w);margin:0 auto;padding:0 24px}
.section{padding:80px 0}
.section-alt{background:var(--surface)}
.section-ice{background:linear-gradient(135deg,var(--ice-pale),#f0f7ff)}

/* ============ NAVIGATION ============ */
.navbar{
  position:sticky;top:0;z-index:500;
  background:rgba(255,255,255,.82);
  backdrop-filter:blur(20px);-webkit-backdrop-filter:blur(20px);
  border-bottom:1px solid var(--border2);
  box-shadow:0 1px 8px rgba(0,0,0,.04);
}
.navbar .wrap{
  display:flex;align-items:center;justify-content:space-between;
  height:62px;
}
.logo{
  display:flex;align-items:center;gap:10px;
  font-weight:800;font-size:1.05rem;color:var(--navy);
}
.logo svg{width:30px;height:30px;flex-shrink:0}
.nav-links{display:flex;align-items:center;gap:4px}
.nav-links a{
  display:inline-block;padding:8px 20px;border-radius:10px;
  font-size:.9rem;font-weight:600;color:var(--slate);
  transition:all .25s;
}
.nav-links a:hover{color:var(--ice);background:var(--ice-pale)}
.nav-links a.active{
  color:#fff;
  background:linear-gradient(135deg,var(--ice),#0284c7);
  box-shadow:0 2px 12px rgba(14,165,233,.3);
}

/* ============ BUTTONS ============ */
.btn{
  display:inline-flex;align-items:center;gap:8px;
  padding:13px 28px;border-radius:12px;
  font-size:.95rem;font-weight:700;
  transition:all .3s;
}
.btn-primary{
  background:linear-gradient(135deg,var(--ice),#0284c7);
  color:#fff;box-shadow:0 4px 18px rgba(14,165,233,.3);
}
.btn-primary:hover{
  transform:translateY(-2px);
  box-shadow:0 6px 24px rgba(14,165,233,.4);
}
.btn-outline{
  background:transparent;color:var(--ice);
  border:2px solid var(--ice);
}
.btn-outline:hover{background:var(--ice);color:#fff}
.btn-white{
  background:#fff;color:var(--navy);
  box-shadow:var(--shadow3);
}
.btn-white:hover{box-shadow:var(--shadow)}
.btn-lg{padding:16px 36px;font-size:1.05rem;border-radius:14px}
.btn-sm{padding:10px 20px;font-size:.85rem;border-radius:10px}

/* ============ HERO ============ */
.hero{
  position:relative;overflow:hidden;
  background:linear-gradient(160deg,#0f172a 0%,#0c4a6e 40%,#0ea5e9 100%);
  color:#fff;padding:100px 0 90px;
}
.hero::before{
  content:'';position:absolute;top:-50%;right:-20%;
  width:700px;height:700px;border-radius:50%;
  background:radial-gradient(circle,rgba(125,211,252,.2),transparent 70%);
  animation:drift 8s ease-in-out infinite;pointer-events:none;
}
.hero::after{
  content:'';position:absolute;bottom:-30%;left:-10%;
  width:500px;height:500px;border-radius:50%;
  background:radial-gradient(circle,rgba(14,165,233,.15),transparent 70%);
  animation:drift 10s ease-in-out infinite 2s;pointer-events:none;
}
.hero-grid{
  display:grid;grid-template-columns:1fr 1fr;gap:60px;align-items:center;
  position:relative;z-index:1;
}
.hero-tag{
  display:inline-block;padding:6px 16px;border-radius:20px;
  background:rgba(255,255,255,.12);font-size:.8rem;font-weight:600;
  letter-spacing:.5px;margin-bottom:16px;
  border:1px solid rgba(255,255,255,.15);
}
.hero h1{font-size:2.8rem;font-weight:900;line-height:1.2;margin-bottom:18px}
.hero h1 span{
  background:linear-gradient(90deg,var(--ice-light),#bae6fd);
  -webkit-background-clip:text;-webkit-text-fill-color:transparent;
  background-clip:text;
}
.hero-desc{font-size:1.1rem;color:rgba(255,255,255,.8);margin-bottom:32px;max-width:480px}
.hero-actions{display:flex;gap:14px;flex-wrap:wrap}
.hero-visual{
  display:flex;align-items:center;justify-content:center;
  position:relative;
}
.hero-globe{
  width:320px;height:320px;border-radius:50%;
  background:linear-gradient(135deg,rgba(14,165,233,.3),rgba(125,211,252,.1));
  border:2px dashed rgba(255,255,255,.15);
  display:flex;align-items:center;justify-content:center;
  animation:drift 6s ease-in-out infinite;
}
.hero-globe svg{width:120px;height:120px;opacity:.9}
.hero-badges{
  position:absolute;display:flex;flex-direction:column;gap:12px;
  right:0;top:50%;transform:translateY(-50%);
}
.hero-badge{
  background:rgba(255,255,255,.12);backdrop-filter:blur(8px);
  border:1px solid rgba(255,255,255,.15);border-radius:10px;
  padding:10px 16px;font-size:.8rem;font-weight:600;
  white-space:nowrap;
}

/* ============ STATS BAR ============ */
.stats-bar{
  background:var(--surface);border-bottom:1px solid var(--border2);
  padding:36px 0;
}
.stats-row{
  display:grid;grid-template-columns:repeat(4,1fr);gap:24px;text-align:center;
}
.stat-item{padding:8px 0}
.stat-num{
  font-size:2rem;font-weight:900;
  background:linear-gradient(135deg,var(--ice),#0284c7);
  -webkit-background-clip:text;-webkit-text-fill-color:transparent;
  background-clip:text;
}
.stat-label{font-size:.85rem;color:var(--slate2);margin-top:4px}

/* ============ FEATURE CARDS ============ */
.sec-head{text-align:center;margin-bottom:48px}
.sec-label{
  display:inline-block;padding:5px 14px;border-radius:20px;
  background:var(--ice-pale);color:var(--ice);
  font-size:.78rem;font-weight:700;letter-spacing:.5px;
  margin-bottom:12px;
}
.sec-title{font-size:2rem;font-weight:900;color:var(--navy);margin-bottom:10px}
.sec-subtitle{font-size:1rem;color:var(--slate2);max-width:560px;margin:0 auto}

.card-grid{
  display:grid;grid-template-columns:repeat(3,1fr);gap:24px;
}
.card{
  background:var(--surface);border-radius:var(--radius);
  padding:32px 28px;border:1px solid var(--border2);
  transition:all .3s;position:relative;overflow:hidden;
}
.card::before{
  content:'';position:absolute;top:0;left:0;right:0;height:4px;
  background:linear-gradient(90deg,var(--ice),#0284c7);
  transform:scaleX(0);transform-origin:left;
  transition:transform .3s;
}
.card:hover{
  transform:translateY(-4px);
  box-shadow:var(--shadow2);
  border-color:var(--ice);
}
.card:hover::before{transform:scaleX(1)}
.card-icon{
  width:52px;height:52px;border-radius:12px;
  background:var(--ice-pale);display:flex;align-items:center;justify-content:center;
  margin-bottom:18px;
}
.card-icon svg{width:26px;height:26px;color:var(--ice)}
.card h3{font-size:1.1rem;font-weight:800;color:var(--navy);margin-bottom:10px}
.card p{font-size:.9rem;color:var(--slate);line-height:1.7}

/* ============ PLATFORMS ============ */
.plat-grid{
  display:grid;grid-template-columns:repeat(4,1fr);gap:20px;
}
.plat-card{
  background:var(--surface);border-radius:var(--radius);
  padding:28px 22px;text-align:center;
  border:1px solid var(--border2);transition:all .3s;
}
.plat-card:hover{border-color:var(--ice);box-shadow:var(--shadow)}
.plat-icon{
  width:56px;height:56px;margin:0 auto 14px;
  border-radius:14px;background:var(--ice-pale);
  display:flex;align-items:center;justify-content:center;
}
.plat-icon svg{width:28px;height:28px;color:var(--ice)}
.plat-card h4{font-size:1rem;font-weight:700;color:var(--navy);margin-bottom:6px}
.plat-card p{font-size:.82rem;color:var(--slate2);margin-bottom:16px}

/* ============ DEEP FEATURES (Alternating rows) ============ */
.deep-row{
  display:grid;grid-template-columns:1fr 1fr;gap:60px;align-items:center;
  padding:60px 0;
}
.deep-row:nth-child(even){direction:rtl}
.deep-row:nth-child(even)>*{direction:ltr}
.deep-media{
  background:linear-gradient(135deg,var(--ice-pale),#dbeafe);
  border-radius:var(--radius2);padding:40px;
  display:flex;align-items:center;justify-content:center;
  min-height:280px;
}
.deep-media svg{width:120px;height:120px;color:var(--ice);opacity:.7}
.deep-info h3{font-size:1.5rem;font-weight:800;color:var(--navy);margin-bottom:14px}
.deep-info p{font-size:.95rem;color:var(--slate);margin-bottom:12px}
.deep-info ul{padding:0}
.deep-info li{
  font-size:.9rem;color:var(--slate);padding:6px 0 6px 22px;
  position:relative;
}
.deep-info li::before{
  content:'';position:absolute;left:0;top:14px;
  width:8px;height:8px;border-radius:50%;background:var(--ice);
}

/* ============ REVIEWS ============ */
.reviews-grid{display:grid;grid-template-columns:repeat(3,1fr);gap:20px}
.rev-card{
  background:var(--surface);border-radius:var(--radius);
  padding:28px;border:1px solid var(--border2);
  transition:all .3s;
}
.rev-card:hover{box-shadow:var(--shadow)}
.rev-header{display:flex;align-items:center;gap:12px;margin-bottom:14px}
.rev-avatar{
  width:42px;height:42px;border-radius:50%;
  background:linear-gradient(135deg,var(--ice),#0284c7);
  display:flex;align-items:center;justify-content:center;
  color:#fff;font-weight:800;font-size:.9rem;flex-shrink:0;
}
.rev-name{font-weight:700;font-size:.95rem;color:var(--navy)}
.rev-stars{color:#f59e0b;font-size:.85rem;margin-top:2px;display:flex;gap:2px}
.rev-stars svg{width:14px;height:14px;fill:#f59e0b}
.rev-text{font-size:.88rem;color:var(--slate);line-height:1.7}

/* ============ COMPARISON TABLE ============ */
.cmp-wrap{overflow-x:auto}
.cmp-table{
  width:100%;border-collapse:collapse;
  background:var(--surface);border-radius:var(--radius);
  overflow:hidden;border:1px solid var(--border2);
}
.cmp-table th,.cmp-table td{
  padding:14px 18px;text-align:left;
  border-bottom:1px solid var(--border2);
  font-size:.88rem;
}
.cmp-table th{
  background:var(--navy);color:#fff;
  font-weight:700;font-size:.85rem;
  letter-spacing:.3px;
}
.cmp-table tr:last-child td{border-bottom:none}
.cmp-table .highlight{background:var(--ice-pale);font-weight:700;color:var(--ice)}

/* ============ FAQ ============ */
.faq-list{max-width:780px;margin:0 auto}
.faq-item{
  border:1px solid var(--border2);border-radius:var(--radius);
  margin-bottom:12px;overflow:hidden;
  background:var(--surface);transition:all .3s;
}
.faq-item.open{border-color:var(--ice);box-shadow:var(--shadow)}
.faq-q{
  display:flex;align-items:center;justify-content:space-between;
  padding:18px 24px;cursor:pointer;
  font-weight:700;font-size:.95rem;color:var(--navy);
  transition:background .2s;
}
.faq-q:hover{background:var(--ice-pale)}
.faq-q svg{
  width:20px;height:20px;color:var(--slate2);
  transition:transform .3s;flex-shrink:0;
}
.faq-item.open .faq-q svg{transform:rotate(180deg);color:var(--ice)}
.faq-a{
  padding:0 24px;max-height:0;overflow:hidden;
  transition:max-height .35s ease,padding .35s;
  font-size:.9rem;color:var(--slate);line-height:1.8;
}
.faq-item.open .faq-a{max-height:600px;padding:0 24px 20px}

/* ============ CTA BANNER ============ */
.cta-banner{
  background:linear-gradient(135deg,#0f172a,#0c4a6e);
  border-radius:var(--radius2);padding:60px 48px;
  text-align:center;color:#fff;
}
.cta-banner h2{font-size:1.8rem;font-weight:900;margin-bottom:12px}
.cta-banner p{font-size:1rem;color:rgba(255,255,255,.75);margin-bottom:28px;max-width:480px;margin-left:auto;margin-right:auto}

/* ============ FOOTER ============ */
.site-footer{
  background:var(--navy);color:rgba(255,255,255,.6);
  padding:36px 0;text-align:center;font-size:.82rem;line-height:1.9;
}
.site-footer .security{
  color:var(--ice-light);font-weight:600;margin-bottom:6px;
}

/* ============ DL PAGE SPECIFICS ============ */
.dl-hero{
  background:linear-gradient(160deg,#0f172a,#0c4a6e 60%,#0ea5e9);
  color:#fff;padding:80px 0 60px;text-align:center;
}
.dl-hero h1{font-size:2.2rem;font-weight:900;margin-bottom:12px}
.dl-hero p{font-size:1rem;color:rgba(255,255,255,.75);margin-bottom:28px}
.dl-main-box{
  background:var(--surface);border-radius:var(--radius2);
  padding:40px;max-width:560px;margin:0 auto;
  color:var(--navy);text-align:center;
  box-shadow:0 12px 40px rgba(0,0,0,.15);
}
.dl-main-box h2{font-size:1.4rem;font-weight:800;margin-bottom:10px}
.dl-meta{display:flex;justify-content:center;gap:18px;margin:14px 0 22px;font-size:.82rem;color:var(--slate2)}
.dl-meta span{
  display:inline-flex;align-items:center;gap:4px;
  padding:4px 12px;border-radius:8px;background:var(--ice-pale);
}

/* Steps */
.steps-grid{counter-reset:step}
.step-card{
  display:grid;grid-template-columns:56px 1fr;gap:20px;
  padding:24px 0;border-bottom:1px solid var(--border2);
  align-items:start;
}
.step-card:last-child{border-bottom:none}
.step-num{
  counter-increment:step;
  width:48px;height:48px;border-radius:50%;
  background:linear-gradient(135deg,var(--ice),#0284c7);
  color:#fff;font-weight:800;font-size:1.1rem;
  display:flex;align-items:center;justify-content:center;
}
.step-card h4{font-size:1rem;font-weight:700;color:var(--navy);margin-bottom:6px}
.step-card p{font-size:.88rem;color:var(--slate)}

/* Version log */
.ver-list{max-width:700px;margin:0 auto}
.ver-item{
  padding:20px 24px;border-left:3px solid var(--ice);
  margin-bottom:16px;background:var(--surface);
  border-radius:0 var(--radius) var(--radius) 0;
  box-shadow:var(--shadow3);
}
.ver-tag{
  display:inline-block;padding:3px 10px;border-radius:6px;
  background:var(--ice);color:#fff;font-size:.75rem;font-weight:700;
  margin-right:8px;
}
.ver-date{font-size:.78rem;color:var(--slate2)}
.ver-item h4{font-size:.95rem;font-weight:700;color:var(--navy);margin:8px 0 4px}
.ver-item p{font-size:.85rem;color:var(--slate)}

/* Requirement cards */
.req-grid{display:grid;grid-template-columns:repeat(2,1fr);gap:20px}
.req-card{
  background:var(--surface);border-radius:var(--radius);
  padding:24px;border:1px solid var(--border2);
}
.req-card h4{font-size:.95rem;font-weight:700;color:var(--navy);margin-bottom:10px;display:flex;align-items:center;gap:8px}
.req-card ul{padding:0}
.req-card li{font-size:.85rem;color:var(--slate);padding:4px 0 4px 18px;position:relative}
.req-card li::before{content:'';position:absolute;left:0;top:12px;width:6px;height:6px;border-radius:50%;background:var(--ice)}

/* Security banner */
.sec-banner{
  background:linear-gradient(135deg,var(--ice-pale),#dbeafe);
  border:1px solid var(--border);border-radius:var(--radius);
  padding:28px 32px;display:flex;align-items:center;gap:16px;
}
.sec-banner svg{width:40px;height:40px;color:var(--ice);flex-shrink:0}
.sec-banner h4{font-size:1rem;font-weight:700;color:var(--navy);margin-bottom:4px}
.sec-banner p{font-size:.88rem;color:var(--slate)}

/* ============ ZH-CN PAGE ============ */
.article-hero{
  background:linear-gradient(160deg,#0f172a,#0c4a6e 50%,#0ea5e9);
  color:#fff;padding:80px 0;
}
.article-hero h1{font-size:2.2rem;font-weight:900;margin-bottom:14px}
.article-hero p{color:rgba(255,255,255,.75);max-width:600px}

.tag-cloud{display:flex;flex-wrap:wrap;gap:8px;margin-top:20px}
.tag-cloud span{
  padding:5px 14px;border-radius:20px;font-size:.78rem;font-weight:600;
  background:rgba(255,255,255,.12);border:1px solid rgba(255,255,255,.15);
}

.article-layout{
  display:grid;grid-template-columns:1fr 320px;gap:40px;
  align-items:start;
}
.article-body{min-width:0}
.article-body h2{
  font-size:1.4rem;font-weight:800;color:var(--navy);
  margin:36px 0 14px;padding-bottom:10px;
  border-bottom:2px solid var(--ice);display:inline-block;
}
.article-body h3{font-size:1.1rem;font-weight:700;color:var(--navy);margin:20px 0 8px}
.article-body p{font-size:.92rem;color:var(--slate);margin-bottom:14px}
.article-body ul{padding:0;margin-bottom:14px}
.article-body [id]{scroll-margin-top:88px}
.article-body .cta-banner h2{
  color:#fff;border-bottom:none;display:block;padding-bottom:0;
  margin:0 0 12px;
}
.article-body .cta-banner p{color:rgba(255,255,255,.82);margin-bottom:28px}
.article-body li{font-size:.9rem;color:var(--slate);padding:4px 0 4px 20px;position:relative}
.article-body li::before{content:'';position:absolute;left:0;top:13px;width:7px;height:7px;border-radius:50%;background:var(--ice)}

/* Sidebar */
.sidebar{position:sticky;top:80px}
.side-box{
  background:var(--surface);border-radius:var(--radius);
  padding:24px;border:1px solid var(--border2);
  margin-bottom:20px;
}
.side-box h4{font-size:.95rem;font-weight:700;color:var(--navy);margin-bottom:14px;padding-bottom:8px;border-bottom:1px solid var(--border2)}
.side-toc a{
  display:block;padding:7px 0;font-size:.85rem;color:var(--slate);
  border-left:3px solid transparent;padding-left:12px;
  transition:all .2s;
}
.side-toc a:hover{color:var(--ice);border-color:var(--ice)}
.side-stat{display:flex;justify-content:space-between;padding:8px 0;font-size:.85rem;color:var(--slate);border-bottom:1px solid var(--border2)}
.side-stat:last-child{border-bottom:none}
.side-stat strong{color:var(--navy)}

/* Tips grid */
.tips-grid{display:grid;grid-template-columns:repeat(2,1fr);gap:16px;margin:16px 0}
.tip-card{
  background:var(--surface);border-radius:var(--radius);
  padding:18px;border:1px solid var(--border2);
}
.tip-card h4{font-size:.9rem;font-weight:700;color:var(--navy);margin-bottom:6px}
.tip-card p{font-size:.82rem;color:var(--slate)}

/* ============ RESPONSIVE ============ */
@media(max-width:1024px){
  .hero-grid{grid-template-columns:1fr;text-align:center}
  .hero-desc{margin:0 auto 32px}
  .hero-actions{justify-content:center}
  .hero-visual{display:none}
  .card-grid{grid-template-columns:repeat(2,1fr)}
  .plat-grid{grid-template-columns:repeat(2,1fr)}
  .deep-row{grid-template-columns:1fr;text-align:center}
  .deep-row:nth-child(even){direction:ltr}
  .deep-media{min-height:200px}
  .reviews-grid{grid-template-columns:repeat(2,1fr)}
  .article-layout{grid-template-columns:1fr}
  .sidebar{position:static}
  .stats-row{grid-template-columns:repeat(2,1fr)}
}
@media(max-width:640px){
  .hero{padding:60px 0 50px}
  .hero h1{font-size:1.8rem}
  .section{padding:50px 0}
  .sec-title{font-size:1.5rem}
  .card-grid{grid-template-columns:1fr}
  .plat-grid{grid-template-columns:1fr}
  .reviews-grid{grid-template-columns:1fr}
  .req-grid{grid-template-columns:1fr}
  .tips-grid{grid-template-columns:1fr}
  .stats-row{grid-template-columns:1fr;gap:16px}
  .cta-banner{padding:40px 24px}
  .nav-links a{padding:6px 12px;font-size:.82rem}
}