/* ============================================================
   VPNWS — ai.css
   ChatGPT 加速专题页(zh-CN/ai-tools.html)专属样式
   依赖 base.css / components.css 的设计令牌与既有组件
   ============================================================ */

/* ------------------------------------------------------------
   1. 页首:居中文案 + 事实带(heroStyle: stats-band)
   ------------------------------------------------------------ */
.ai-hero{
  position:relative;
  overflow-x:clip;
  max-width:100%;
  padding-top:20px;
  padding-bottom:6px;
}
.ai-hero::before{
  content:"";
  position:absolute;
  inset:-60px 0 auto 0;
  height:520px;
  background:linear-gradient(180deg,rgba(245,238,230,.6) 0%,rgba(251,250,247,0) 76%);
  pointer-events:none;
  z-index:0;
}
.ai-orb{
  position:absolute;
  z-index:0;
  pointer-events:none;
  top:-70px;
  left:0;
  right:0;
  margin-inline:auto;
  width:min(620px,86vw);
  height:360px;
  border-radius:50%;
  background:radial-gradient(ellipse at 50% 42%,rgba(184,81,42,.11) 0%,rgba(184,81,42,.03) 46%,rgba(184,81,42,0) 74%);
}
.ai-hero .wrap{position:relative;z-index:1}
.ai-hero-copy{position:relative;z-index:2;text-align:center}

.ai-title{
  font-family:var(--font-display);
  font-weight:800;
  font-size:clamp(34px,4.6vw,56px);
  line-height:1.14;
  letter-spacing:-.03em;
  margin:14px auto 12px;
  max-width:19em;
  color:var(--text);
  text-wrap:balance;
}
.ai-sub{
  font-size:18px;
  line-height:1.65;
  color:var(--text-muted);
  max-width:50em;
  margin:0 auto 18px;
}
.ai-sub strong{color:var(--text);font-weight:600}
.ai-pills{justify-content:center;max-width:660px;margin:0 auto 20px}

/* 事实带:四格等宽 */
.ai-facts{
  display:grid;
  grid-template-columns:repeat(4,minmax(0,1fr));
  max-width:800px;
  margin:0 auto;
  border:1px solid var(--border);
  border-radius:var(--r-lg);
  background:var(--bg-panel);
  box-shadow:var(--hl-edge),0 12px 30px -20px var(--accent-shadow);
  position:relative;
  z-index:3;
}
.ai-facts li{
  position:relative;
  display:flex;
  align-items:center;
  justify-content:center;
  gap:6px;
  min-height:46px;
  padding:0 8px;
  font-size:13.5px;
  color:var(--text-muted);
  text-align:center;
  white-space:nowrap;
  min-width:0;
}
.ai-facts li+li::before{
  content:"";
  position:absolute;
  left:0;
  top:12px;
  bottom:12px;
  width:1px;
  background:var(--border);
}
.ai-facts b{
  font-family:var(--font-mono);
  font-weight:600;
  font-size:14px;
  letter-spacing:-.01em;
  color:var(--text);
}

/* ------------------------------------------------------------
   2. 正文排版
   ------------------------------------------------------------ */
.prose{padding-bottom:var(--sp-7)}
.prose section{padding-top:var(--sp-8);padding-bottom:0}
.prose section:first-of-type{padding-top:var(--sp-7)}

.prose h2{
  font-size:clamp(24px,2.8vw,32px);
  line-height:1.22;
  letter-spacing:-.025em;
  margin-bottom:var(--sp-4);
}
.prose h3{
  font-size:19px;
  letter-spacing:-.015em;
  margin:var(--sp-5) 0 var(--sp-3);
}
.prose h3:first-child{margin-top:0}
.prose p{
  max-width:74ch;
  margin-bottom:var(--sp-4);
  color:var(--text-muted);
}
.prose p strong{color:var(--text);font-weight:600}

.prose ul{
  display:flex;
  flex-direction:column;
  gap:10px;
  max-width:74ch;
  margin-bottom:var(--sp-4);
}
.prose ul li{
  position:relative;
  padding-left:20px;
  font-size:16.5px;
  line-height:1.7;
  color:var(--text-muted);
}
.prose ul li::before{
  content:"";
  position:absolute;
  left:2px;
  top:.72em;
  width:6px;
  height:6px;
  border-radius:50%;
  background:var(--accent);
  opacity:.5;
}
.prose ul li strong{color:var(--text);font-weight:600}

.prose .callout{margin:var(--sp-5) 0 0;max-width:74ch}
.prose .table-scroll{margin:var(--sp-5) 0 var(--sp-4)}
.prose pre{margin:var(--sp-4) 0 var(--sp-5)}

/* ------------------------------------------------------------
   3. 失败现象卡
   ------------------------------------------------------------ */
.fail-grid{
  display:grid;
  grid-template-columns:repeat(2,minmax(0,1fr));
  gap:var(--sp-4);
  margin-top:var(--sp-5);
}
.fail-card{
  background:var(--bg-panel);
  border:1px solid var(--border);
  border-radius:var(--r-lg);
  padding:var(--sp-4) var(--sp-5);
  box-shadow:var(--hl-edge);
  min-width:0;
  transition:transform .16s,box-shadow .16s;
}
.fail-card:hover{transform:translateY(-2px);box-shadow:var(--shadow-soft)}
.fail-card h3{
  display:flex;
  align-items:flex-start;
  gap:8px;
  font-size:16px;
  line-height:1.45;
  margin:0 0 8px;
}
.fail-card h3 svg{
  width:15px;
  height:15px;
  flex-shrink:0;
  margin-top:4px;
  color:var(--warn);
}
.fail-card p{
  font-size:14.5px;
  line-height:1.7;
  color:var(--text-muted);
  margin-bottom:0;
  max-width:none;
}

/* ------------------------------------------------------------
   4. 选线建议卡
   ------------------------------------------------------------ */
.advice-grid{
  display:grid;
  grid-template-columns:repeat(3,minmax(0,1fr));
  gap:var(--sp-4);
  margin:var(--sp-5) 0 var(--sp-5);
}
.advice-card{
  display:flex;
  flex-direction:column;
  background:var(--bg-panel-2);
  border:1px solid var(--border);
  border-radius:var(--r-xl);
  padding:var(--sp-5);
  box-shadow:var(--hl-edge);
  min-width:0;
  transition:transform .16s,box-shadow .16s;
}
.advice-card:hover{transform:translateY(-2px);box-shadow:var(--shadow-soft)}
.advice-tag{
  display:inline-flex;
  align-items:center;
  align-self:flex-start;
  min-height:24px;
  padding:0 10px;
  margin-bottom:var(--sp-3);
  border-radius:var(--r-pill);
  background:var(--bg-panel);
  border:1px solid var(--border-strong);
  font-family:var(--font-mono);
  font-size:11.5px;
  font-weight:600;
  letter-spacing:.02em;
  color:var(--text-muted);
  max-width:100%;
  overflow:hidden;
  white-space:nowrap;
}
.advice-card h3{font-size:18px;line-height:1.35;margin:0 0 10px}
.advice-card p{
  font-size:14.5px;
  line-height:1.7;
  color:var(--text-muted);
  margin-bottom:0;
  max-width:none;
}

.advice-actions{
  display:flex;
  flex-wrap:wrap;
  gap:12px;
  margin-bottom:var(--sp-4);
}
.advice-note{
  font-size:14.5px;
  color:var(--text-soft);
  max-width:74ch;
  margin-bottom:0;
}

/* ------------------------------------------------------------
   5. 断点
   ------------------------------------------------------------ */
@media (max-width:960px){
  .advice-grid{grid-template-columns:1fr;gap:var(--sp-3)}
  .advice-card{padding:var(--sp-4) var(--sp-5)}
}
@media (max-width:768px){
  .ai-title{font-size:40px}
  .ai-sub{font-size:16.5px}
  .ai-facts{grid-template-columns:repeat(2,minmax(0,1fr))}
  .ai-facts li{min-height:42px}
  .ai-facts li:nth-child(3)::before{display:none}
  .fail-grid{grid-template-columns:1fr}
  .prose section{padding-top:var(--sp-7)}
}
@media (max-width:640px){
  .ai-title{font-size:34px;letter-spacing:-.02em}
  .ai-facts li{font-size:12.5px;gap:5px;padding:0 6px}
  .ai-facts b{font-size:13px}
  .advice-actions{flex-direction:column;align-items:stretch}
  .advice-actions .btn{width:100%}
}