:root{
  --primary:#1f8fff;
  --primary-dark:#0f6fd6;
  --primary-soft:#e8f3ff;
  --accent:#0fc888;
  --ink:#1a2230;
  --ink-2:#5a6473;
  --line:#eceff3;
  --bg:#f6f8fb;
  --card:#ffffff;
  --shadow:0 8px 30px rgba(20,40,80,.08);
  --radius:16px;
}
*{margin:0;padding:0;box-sizing:border-box}
html{scroll-behavior:smooth}
body{
  font-family:-apple-system,BlinkMacSystemFont,"Segoe UI","PingFang SC","Microsoft YaHei",sans-serif;
  color:var(--ink);background:var(--bg);line-height:1.6;
}
a{color:inherit;text-decoration:none}
.btn{cursor:pointer;border:none;border-radius:999px;padding:10px 22px;font-size:14px;font-weight:600;transition:.2s;display:inline-block}
.btn-primary{background:linear-gradient(135deg,var(--primary),var(--primary-dark));color:#fff;box-shadow:0 6px 18px rgba(31,143,255,.35)}
.btn-primary:hover{transform:translateY(-1px);box-shadow:0 10px 24px rgba(31,143,255,.45)}
.btn-ghost{background:transparent;color:var(--ink);border:1px solid var(--line)}
.btn-ghost:hover{background:var(--primary-soft);color:var(--primary)}

/* 导航 */
.navbar{position:sticky;top:0;z-index:50;background:rgba(255,255,255,.85);backdrop-filter:blur(12px);border-bottom:1px solid var(--line)}
.nav-inner{max-width:1180px;margin:0 auto;padding:14px 24px;display:flex;align-items:center;gap:24px}
.brand{display:flex;align-items:center;gap:10px;font-weight:800;font-size:18px}
.brand-logo{width:34px;height:34px;border-radius:10px;background:linear-gradient(135deg,var(--primary),var(--accent));color:#fff;display:grid;place-items:center;font-weight:800;font-size:18px}
.nav-links{display:flex;gap:26px;margin-left:18px;flex:1}
.nav-links a{color:var(--ink-2);font-weight:500;font-size:15px;position:relative;padding:4px 0}
.nav-links a.active,.nav-links a:hover{color:var(--primary)}
.nav-links a.active::after{content:"";position:absolute;left:0;right:0;bottom:-6px;height:3px;border-radius:3px;background:var(--primary)}
.nav-actions{display:flex;gap:10px}

/* 英雄区 */
.hero{position:relative;overflow:hidden;padding:84px 24px 64px;text-align:center}
.hero-bg{position:absolute;inset:0;background:
  radial-gradient(700px 360px at 20% 0%,rgba(31,143,255,.16),transparent 60%),
  radial-gradient(600px 340px at 90% 10%,rgba(15,200,136,.14),transparent 60%);}
.hero-inner{position:relative;max-width:880px;margin:0 auto}
.badge{display:inline-block;background:var(--primary-soft);color:var(--primary);font-weight:600;font-size:13px;padding:6px 14px;border-radius:999px;margin-bottom:20px}
.hero-title{font-size:46px;line-height:1.2;font-weight:800;letter-spacing:-.5px}
.hero-sub{margin:18px auto 0;max-width:620px;color:var(--ink-2);font-size:17px}
.hero-search{margin:30px auto 0;max-width:580px;display:flex;gap:10px;background:#fff;padding:8px;border-radius:999px;box-shadow:var(--shadow)}
.hero-search input{flex:1;border:none;outline:none;padding:10px 18px;font-size:15px;background:transparent}
.hero-stats{margin-top:40px;display:flex;justify-content:center;gap:48px;flex-wrap:wrap}
.hero-stats div{display:flex;flex-direction:column}
.hero-stats strong{font-size:28px;color:var(--primary)}
.hero-stats span{color:var(--ink-2);font-size:13px}

/* 通用 section */
.section{max-width:1180px;margin:0 auto;padding:72px 24px}
.section-head{text-align:center;margin-bottom:36px}
.section-head h2{font-size:32px;font-weight:800}
.section-head p{margin-top:10px;color:var(--ink-2);font-size:16px}

/* tabs */
.tabs{display:flex;gap:10px;justify-content:center;flex-wrap:wrap;margin-bottom:30px}
.tab{cursor:pointer;border:1px solid var(--line);background:#fff;color:var(--ink-2);padding:8px 18px;border-radius:999px;font-size:14px;font-weight:600;transition:.2s}
.tab:hover{border-color:var(--primary);color:var(--primary)}
.tab.active{background:var(--primary);color:#fff;border-color:var(--primary)}

/* 工具网格 */
.tool-grid{display:grid;grid-template-columns:repeat(4,1fr);gap:18px}
.tool-card{background:var(--card);border:1px solid var(--line);border-radius:var(--radius);padding:20px;cursor:pointer;transition:.22s;position:relative;overflow:hidden}
.tool-card:hover{transform:translateY(-4px);box-shadow:var(--shadow);border-color:transparent}
.tool-card .ticon{width:48px;height:48px;border-radius:12px;display:grid;place-items:center;font-size:24px;margin-bottom:14px}
.tool-card h3{font-size:17px;font-weight:700}
.tool-card .tdesc{color:var(--ink-2);font-size:13.5px;margin-top:8px;min-height:42px}
.tool-card .tmeta{display:flex;align-items:center;justify-content:space-between;margin-top:14px}
.tool-card .ttag{font-size:12px;color:var(--primary);background:var(--primary-soft);padding:3px 10px;border-radius:999px}
.tool-card .tuse{font-size:12px;color:var(--ink-2)}
.tool-card .tuse b{color:var(--accent)}
.empty-tip{text-align:center;color:var(--ink-2);padding:40px}

/* 对话 */
.chat-section{background:linear-gradient(180deg,#fff,var(--bg))}
.chat-box{max-width:820px;margin:0 auto;background:#fff;border:1px solid var(--line);border-radius:20px;box-shadow:var(--shadow);overflow:hidden;display:flex;flex-direction:column;height:560px}
.chat-messages{flex:1;overflow-y:auto;padding:22px;display:flex;flex-direction:column;gap:16px}
.msg{display:flex;gap:12px;max-width:85%}
.msg .avatar{width:36px;height:36px;border-radius:10px;flex:none;display:grid;place-items:center;font-weight:700;color:#fff;background:linear-gradient(135deg,var(--primary),var(--accent))}
.msg.bot{align-self:flex-start}
.msg.user{align-self:flex-end;flex-direction:row-reverse}
.msg .bubble{padding:12px 16px;border-radius:14px;font-size:15px;white-space:pre-wrap;word-break:break-word}
.msg.bot .bubble{background:var(--bg);border:1px solid var(--line)}
.msg.user .bubble{background:var(--primary);color:#fff}
.msg .bubble .cursor{display:inline-block;width:8px;height:16px;background:var(--primary);animation:blink 1s steps(2) infinite;vertical-align:middle}
@keyframes blink{50%{opacity:0}}
.chat-input{display:flex;gap:10px;padding:14px;border-top:1px solid var(--line);align-items:flex-end}
.chat-input textarea{flex:1;border:1px solid var(--line);border-radius:12px;padding:12px 14px;font-size:15px;resize:none;outline:none;font-family:inherit;max-height:120px}
.chat-input textarea:focus{border-color:var(--primary)}
.chat-foot{text-align:center;font-size:12px;color:var(--ink-2);padding:8px;border-top:1px solid var(--line)}

/* 能力 */
.feature-grid{display:grid;grid-template-columns:repeat(4,1fr);gap:18px}
.feature{background:#fff;border:1px solid var(--line);border-radius:var(--radius);padding:24px;transition:.2s}
.feature:hover{box-shadow:var(--shadow);transform:translateY(-3px)}
.ficon{font-size:28px;margin-bottom:12px}
.feature h3{font-size:17px;margin-bottom:8px}
.feature p{color:var(--ink-2);font-size:14px}

/* 关于 */
.about-card{background:#fff;border:1px solid var(--line);border-radius:20px;padding:40px;display:grid;grid-template-columns:1.4fr 1fr;gap:40px;box-shadow:var(--shadow)}
.about-card h2{font-size:26px;margin-bottom:14px}
.about-card p{color:var(--ink-2);font-size:15px}
.contact{background:var(--bg);border-radius:16px;padding:24px}
.contact h3{font-size:18px;margin-bottom:12px}
.contact p{font-size:15px;margin-bottom:8px;color:var(--ink)}
.contact span{color:var(--ink-2)}
.contact a{color:var(--primary);font-weight:600}

/* 底部 */
.footer{background:#0e1726;color:#cdd6e4;padding:40px 24px;text-align:center}
.foot-inner{max-width:900px;margin:0 auto}
.foot-brand{display:flex;align-items:center;justify-content:center;gap:10px;font-weight:800;font-size:18px;color:#fff;margin-bottom:14px}
.copyright{font-size:13px;color:#9aa7bd}
.copyright a{color:#9aa7bd;text-decoration:underline}
.foot-contact{margin-top:6px;font-size:13px;color:#9aa7bd}

/* 响应式 */
@media(max-width:980px){
  .tool-grid,.feature-grid{grid-template-columns:repeat(2,1fr)}
  .hero-title{font-size:36px}
  .about-card{grid-template-columns:1fr}
}
@media(max-width:560px){
  .nav-links{display:none}
  .tool-grid,.feature-grid{grid-template-columns:1fr}
  .hero-title{font-size:30px}
  .hero-stats{gap:26px}
}