/* ===== 我在AI 无限词版官网 ===== */
:root{
  --primary:#FF5C8A;
  --primary-deep:#F03D74;
  --primary-soft:#FFE4EE;
  --deep:#2A1A3D;
  --text:#3E2C50;
  --muted:#6F5E7C;
  --bg:#FFF9FB;
  --bg-soft:#FFF0F6;
  --card:#FFFFFF;
  --border:#F4D8E5;
  --green:#2EC57E;
  --radius:18px;
  --shadow:0 10px 30px rgba(240,61,116,.08);
  --shadow-hover:0 18px 42px rgba(240,61,116,.16);
}
*{margin:0;padding:0;box-sizing:border-box}
html{scroll-behavior:smooth;scroll-padding-top:76px}
body{font-family:-apple-system,"PingFang SC","Microsoft YaHei","Noto Sans SC","Segoe UI",sans-serif;background:var(--bg);color:var(--text);line-height:1.6;-webkit-font-smoothing:antialiased}
img{display:block;max-width:100%}
a{text-decoration:none;color:inherit}
ul{list-style:none}
.wrap{max-width:1200px;margin:0 auto;padding:0 24px}
.sec{padding:88px 0}
.bg-soft{background:var(--bg-soft)}
.sec-title{font-size:34px;font-weight:700;color:var(--deep);text-align:center;line-height:1.3}
.ver{font-size:20px;color:var(--primary);font-weight:700;vertical-align:middle;margin-left:6px}
.sec-sub{text-align:center;color:var(--muted);margin-top:10px;font-size:15px}
.sec-title.left{text-align:left}
.sec-title.white{color:#fff}
.narrow{max-width:820px}

/* 卡片 */
.card{background:var(--card);border:1px solid var(--border);border-radius:var(--radius);box-shadow:var(--shadow);transition:transform .25s,box-shadow .25s;padding:26px}
.card:hover{transform:translateY(-6px);box-shadow:var(--shadow-hover)}

/* 按钮 */
.btn{display:inline-flex;align-items:center;justify-content:center;background:linear-gradient(90deg,var(--primary),var(--primary-deep));color:#fff;border-radius:999px;font-weight:600;border:none;cursor:pointer;transition:transform .25s,box-shadow .25s}
.btn:hover{transform:translateY(-2px);box-shadow:var(--shadow-hover)}
.btn-sm{height:36px;padding:0 18px;font-size:13px}
.btn-lg{height:54px;padding:0 36px;font-size:16px}

/* ===== 1 导航 ===== */
.nav{position:fixed;top:0;left:0;right:0;z-index:100;background:rgba(255,249,251,.92);backdrop-filter:blur(10px);transition:box-shadow .3s}
.nav.scrolled{box-shadow:0 6px 24px rgba(240,61,116,.12)}
.nav-inner{height:64px;display:flex;align-items:center;gap:28px}
.logo{font-size:22px;font-weight:800;color:var(--primary-deep);letter-spacing:1px}
.nav-menu{display:flex;gap:24px;margin-left:auto}
.nav-menu a{font-size:14px;color:var(--text);font-weight:500;position:relative;padding:6px 2px}
.nav-menu a:hover{color:var(--primary-deep)}
.nav-download{margin-left:8px}

/* ===== 2 Hero ===== */
.hero{padding:140px 0 90px;background:linear-gradient(180deg,var(--bg-soft),var(--bg))}
.hero-inner{display:grid;grid-template-columns:1.05fr .95fr;gap:56px;align-items:center}
.hero h1{font-size:44px;font-weight:800;color:var(--deep);line-height:1.25}
.hero-desc{margin:20px 0 34px;font-size:17px;color:var(--text);max-width:520px}
.hero-btn{font-size:17px;height:56px;padding:0 40px}

.chat{max-width:480px;margin:0 auto;background:var(--card);border:1px solid var(--border);border-radius:22px;box-shadow:var(--shadow-hover);overflow:hidden}
.chat-head{display:flex;align-items:center;gap:12px;padding:14px 18px;background:linear-gradient(90deg,var(--primary-soft),var(--bg-soft));border-bottom:1px solid var(--border)}
.chat-avatar{width:46px;height:46px;border-radius:50%;object-fit:cover;border:2px solid #fff}
.chat-user{display:flex;flex-direction:column;line-height:1.35}
.chat-name{font-weight:700;font-size:16px;color:var(--deep)}
.chat-status{font-size:12px;color:var(--green);display:flex;align-items:center;gap:5px}
.dot{width:8px;height:8px;border-radius:50%;background:var(--green);display:inline-block}
.chat-body{display:flex;flex-direction:column;gap:12px;padding:18px;min-height:300px;background:linear-gradient(180deg,#F3EBFB,#EADDF5);overflow-y:auto}
.bubble{max-width:80%;padding:12px 16px;border-radius:16px;font-size:14px;line-height:1.65;word-break:break-word}
.bubble.ai{align-self:flex-start;background:#fff;color:var(--text);border:1px solid var(--border);border-bottom-left-radius:4px}
.bubble.user{align-self:flex-end;background:linear-gradient(90deg,var(--primary),var(--primary-deep));color:#fff;border-bottom-right-radius:4px}
.chat-input{display:flex;align-items:center;gap:10px;padding:14px 18px;background:#fff;border-top:1px solid var(--border)}
.chat-input input{flex:1;height:44px;border:1px solid var(--border);border-radius:999px;padding:0 18px;font-size:13px;color:var(--text);background:var(--bg-soft);outline:none}
.send{width:44px;height:44px;border-radius:50%;background:linear-gradient(90deg,var(--primary),var(--primary-deep));color:#fff;border:none;cursor:pointer;flex-shrink:0;display:flex;align-items:center;justify-content:center;transition:background .3s,transform .25s}
.send svg{width:20px;height:20px}
.send:hover{transform:translateY(-2px)}
.send.disabled{background:#E0DAE6;color:#A79FB5;cursor:not-allowed;transform:none}

.persona-pick{margin-top:26px}
.pick-title{font-size:14px;font-weight:600;color:var(--muted);text-align:center;margin-bottom:14px}
.pick-list{display:grid;grid-template-columns:repeat(6,1fr);gap:12px;max-width:480px;margin:0 auto}
.pick-item{display:flex;flex-direction:column;align-items:center;gap:8px}
.pick-item img{width:100%;aspect-ratio:1;border-radius:16px;object-fit:cover;border:2px solid var(--border);transition:transform .25s,box-shadow .25s}
.pick-item:hover img{transform:translateY(-4px);box-shadow:var(--shadow-hover)}
.pick-item span{font-size:14px;font-weight:600;color:var(--text)}

/* ===== 3 三步上手 ===== */
.grid3{display:grid;grid-template-columns:repeat(3,1fr);gap:22px;margin-top:44px}
.step{position:relative;padding:30px 26px}
.step-num{font-size:40px;font-weight:800;color:var(--primary-soft);line-height:1;display:block;margin-bottom:14px}
.step h3{font-size:19px;color:var(--deep);margin-bottom:8px}
.step p{font-size:14px;color:var(--muted)}

/* ===== 4/9 图文模块 ===== */
.split{display:grid;grid-template-columns:1fr 1fr;gap:56px;align-items:center}
.split.reverse .split-media{order:2}
.split-media img{width:100%;max-width:480px;margin:0 auto;border-radius:var(--radius);box-shadow:var(--shadow)}
.lead{margin:16px 0 22px;font-size:15px;color:var(--text)}
.check-list li{position:relative;padding-left:30px;margin-bottom:12px;font-size:15px;color:var(--text)}
.check-list li::before{content:"";position:absolute;left:0;top:4px;width:20px;height:20px;border-radius:50%;background:var(--primary-soft);background-image:url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 24 24' fill='none' stroke='%23F03D74' stroke-width='3' stroke-linecap='round' stroke-linejoin='round'%3E%3Cpolyline points='20 6 9 17 4 12'/%3E%3C/svg%3E");background-repeat:no-repeat;background-position:center;background-size:13px}

/* ===== 5 功能 ===== */
.grid4{display:grid;grid-template-columns:repeat(4,1fr);gap:22px;margin-top:44px}
.feat-icon{width:48px;height:48px;border-radius:14px;background:var(--primary-soft);background-repeat:no-repeat;background-position:center;background-size:24px;margin-bottom:16px}
.ic-chat{background-image:url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 24 24' fill='none' stroke='%23F03D74' stroke-width='2' stroke-linecap='round' stroke-linejoin='round'%3E%3Cpath d='M21 11.5a8.38 8.38 0 0 1-.9 3.8 8.5 8.5 0 0 1-7.6 4.7 8.38 8.38 0 0 1-3.8-.9L3 21l1.9-5.7a8.38 8.38 0 0 1-.9-3.8 8.5 8.5 0 0 1 4.7-7.6 8.38 8.38 0 0 1 3.8-.9h.5a8.48 8.48 0 0 1 8 8v.5z'/%3E%3C/svg%3E")}
.ic-heart{background-image:url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 24 24' fill='none' stroke='%23F03D74' stroke-width='2' stroke-linecap='round' stroke-linejoin='round'%3E%3Cpath d='M20.84 4.61a5.5 5.5 0 0 0-7.78 0L12 5.67l-1.06-1.06a5.5 5.5 0 0 0-7.78 7.78l1.06 1.06L12 21.23l7.78-7.78 1.06-1.06a5.5 5.5 0 0 0 0-7.78z'/%3E%3C/svg%3E")}
.ic-star{background-image:url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 24 24' fill='none' stroke='%23F03D74' stroke-width='2' stroke-linecap='round' stroke-linejoin='round'%3E%3Cpolygon points='12 2 15.09 8.26 22 9.27 17 14.14 18.18 21.02 12 17.77 5.82 21.02 7 14.14 2 9.27 8.91 8.26 12 2'/%3E%3C/svg%3E")}
.ic-shield{background-image:url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 24 24' fill='none' stroke='%23F03D74' stroke-width='2' stroke-linecap='round' stroke-linejoin='round'%3E%3Cpath d='M12 22s8-4 8-10V5l-8-3-8 3v7c0 6 8 10 8 10z'/%3E%3C/svg%3E")}
.ic-lock{background-image:url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 24 24' fill='none' stroke='%23F03D74' stroke-width='2' stroke-linecap='round' stroke-linejoin='round'%3E%3Crect x='3' y='11' width='18' height='11' rx='2' ry='2'/%3E%3Cpath d='M7 11V7a5 5 0 0 1 10 0v4'/%3E%3C/svg%3E")}
.ic-key{background-image:url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 24 24' fill='none' stroke='%23F03D74' stroke-width='2' stroke-linecap='round' stroke-linejoin='round'%3E%3Cpolyline points='3 6 5 6 21 6'/%3E%3Cpath d='M19 6v14a2 2 0 0 1-2 2H7a2 2 0 0 1-2-2V6m3 0V4a2 2 0 0 1 2-2h4a2 2 0 0 1 2 2v2'/%3E%3C/svg%3E")}
.ic-eye{background-image:url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 24 24' fill='none' stroke='%23F03D74' stroke-width='2' stroke-linecap='round' stroke-linejoin='round'%3E%3Cpath d='M17.94 17.94A10.07 10.07 0 0 1 12 20c-7 0-11-8-11-8a18.45 18.45 0 0 1 5.06-5.94M9.9 4.24A9.12 9.12 0 0 1 12 4c7 0 11 8 11 8a18.5 18.5 0 0 1-2.16 3.19m-6.72-1.07a3 3 0 1 1-4.24-4.24'/%3E%3Cline x1='1' y1='1' x2='23' y2='23'/%3E%3C/svg%3E")}
.ic-child{background-image:url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 24 24' fill='none' stroke='%23F03D74' stroke-width='2' stroke-linecap='round' stroke-linejoin='round'%3E%3Ccircle cx='12' cy='12' r='10'/%3E%3Cpath d='M8 14s1.5 2 4 2 4-2 4-2'/%3E%3Cline x1='9' y1='9' x2='9.01' y2='9'/%3E%3Cline x1='15' y1='9' x2='15.01' y2='9'/%3E%3C/svg%3E")}
.feat h3{font-size:18px;color:var(--deep);margin-bottom:6px}
.feat p{font-size:14px;color:var(--muted);margin-top:8px}
.feat .pain{font-size:14px;color:var(--primary-deep);font-weight:600;background:var(--primary-soft);display:inline-block;padding:3px 12px;border-radius:999px;margin-top:0}

/* ===== 6 对比表 ===== */
.cmp-scroll{overflow-x:auto;margin-top:44px;border-radius:var(--radius);box-shadow:var(--shadow)}
.cmp{width:100%;border-collapse:collapse;background:var(--card);min-width:0;font-size:14px}
.cmp th,.cmp td{padding:15px 16px;text-align:center;border-bottom:1px solid var(--border)}
.cmp th{background:var(--deep);color:#fff;font-weight:600}
.cmp td:first-child{font-weight:600;color:var(--deep);background:var(--bg)}
.cmp .th-brand{background:linear-gradient(90deg,var(--primary),var(--primary-deep))}
.cmp .td-brand{background:var(--primary-soft);color:var(--primary-deep);font-weight:700}
.cmp-hint{display:none;text-align:center;color:var(--muted);font-size:12px;margin-top:10px}

/* ===== 7 场景 ===== */
.scene-list{display:grid;grid-template-columns:repeat(2,1fr);gap:14px;margin:40px 0 52px;max-width:820px;margin-left:auto;margin-right:auto}
.scene-list li{background:var(--card);border:1px solid var(--border);border-radius:14px;padding:14px 16px 14px 44px;font-size:15px;color:var(--text);position:relative}
.scene-list li::before{content:"";position:absolute;left:16px;top:16px;width:20px;height:20px;border-radius:50%;background:var(--primary-soft);background-image:url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 24 24' fill='none' stroke='%23F03D74' stroke-width='3' stroke-linecap='round' stroke-linejoin='round'%3E%3Cpolyline points='20 6 9 17 4 12'/%3E%3C/svg%3E");background-repeat:no-repeat;background-position:center;background-size:13px}
.vs{display:grid;grid-template-columns:1fr auto 1fr;gap:26px;align-items:center;max-width:900px;margin:0 auto}
.vs-card p{font-size:14px;color:var(--muted);margin-top:10px}
.vs-card.good{border-color:var(--primary);background:linear-gradient(180deg,#fff,var(--bg-soft))}
.vs-badge{width:64px;height:64px;border-radius:50%;background:linear-gradient(135deg,var(--primary),var(--primary-deep));color:#fff;font-weight:800;font-size:16px;display:flex;align-items:center;justify-content:center;box-shadow:var(--shadow-hover);letter-spacing:1px}

/* ===== 8 数据 ===== */
.data-sec{background:linear-gradient(135deg,#2A1A3D,#4A2A63)}
.data-item{text-align:center;padding:10px 0}
.data-item .num{font-size:46px;font-weight:800;background:linear-gradient(90deg,#FF8FB0,#FF5C8A);-webkit-background-clip:text;background-clip:text;-webkit-text-fill-color:transparent;display:inline-block}
.data-item p{margin-top:6px;color:#E3D6F0;font-size:15px}

/* ===== 10 评价 ===== */
.review{padding:22px}
.review-head{display:flex;align-items:center;gap:12px;margin-bottom:12px}
.avatar{width:44px;height:44px;border-radius:50%;background:linear-gradient(135deg,var(--primary),var(--primary-deep));color:#fff;font-size:18px;font-weight:700;display:flex;align-items:center;justify-content:center;flex-shrink:0}
.review-head b{display:block;font-size:15px;color:var(--deep)}
.stars{font-style:normal;font-size:13px;color:#FFB800;letter-spacing:2px}
.review p{font-size:14px;color:var(--text)}

/* ===== 11 隐私 ===== */
.pri h3{font-size:17px;color:var(--deep);margin-bottom:8px}
.pri p{font-size:14px;color:var(--muted)}

/* ===== 12 版本更新 ===== */
.update-card{margin-top:40px;max-width:640px;margin-left:auto;margin-right:auto}
.update-head{display:flex;align-items:center;gap:16px;margin-bottom:20px}
.ver-badge{background:linear-gradient(90deg,var(--primary),var(--primary-deep));color:#fff;font-weight:700;font-size:16px;padding:6px 16px;border-radius:999px}
.update-date{color:var(--muted);font-size:14px}
.update-list li{position:relative;padding:9px 0 9px 26px;font-size:15px;color:var(--text);border-bottom:1px dashed var(--border)}
.update-list li:last-child{border-bottom:none}
.update-list li::before{content:"";position:absolute;left:4px;top:16px;width:8px;height:8px;border-radius:50%;background:var(--primary)}

/* ===== 13 FAQ ===== */
.faq{margin-top:40px}
.faq-item{background:var(--card);border:1px solid var(--border);border-radius:16px;margin-bottom:14px;overflow:hidden;transition:box-shadow .25s}
.faq-item.open{box-shadow:var(--shadow)}
.faq-q{width:100%;display:flex;align-items:center;justify-content:space-between;gap:16px;background:none;border:none;padding:18px 22px;font-size:15px;font-weight:600;color:var(--deep);cursor:pointer;text-align:left;font-family:inherit}
.faq-icon{position:relative;width:18px;height:18px;flex-shrink:0}
.faq-icon::before,.faq-icon::after{content:"";position:absolute;background:var(--primary);border-radius:2px;transition:transform .3s}
.faq-icon::before{width:18px;height:2px;top:8px;left:0}
.faq-icon::after{width:2px;height:18px;top:0;left:8px}
.faq-item.open .faq-icon::after{transform:scaleY(0)}
.faq-a{max-height:0;overflow:hidden;transition:max-height .35s ease}
.faq-item.open .faq-a{max-height:300px}
.faq-a p{padding:0 22px 20px;font-size:14px;color:var(--muted)}

/* ===== 14 下载 ===== */
.download{background:linear-gradient(180deg,var(--bg-soft),var(--bg));text-align:center}
.dl-meta{color:var(--muted);font-size:14px;margin-top:12px}
.dl-btns{display:flex;justify-content:center;gap:20px;margin-top:28px}
.dl-btn{min-width:280px;font-size:16px}
.dl-tip{margin-top:24px;color:var(--primary-deep);font-size:14px;font-weight:500}

/* ===== 15 页脚 ===== */
.footer{background:var(--deep);color:#C9B8DC;text-align:center;padding:34px 0;font-size:14px}
.footer-link{color:#fff;font-weight:600;text-decoration:none}

/* ===== 16 返回顶部 ===== */
.to-top{position:fixed;right:28px;bottom:28px;width:46px;height:46px;border-radius:50%;background:linear-gradient(135deg,var(--primary),var(--primary-deep));color:#fff;border:none;cursor:pointer;opacity:0;pointer-events:none;transition:opacity .3s,transform .25s;box-shadow:var(--shadow-hover);display:flex;align-items:center;justify-content:center;z-index:99}
.to-top svg{width:20px;height:20px}
.to-top.show{opacity:1;pointer-events:auto}
.to-top:hover{transform:translateY(-3px)}

/* ===== 响应式 ===== */
@media (max-width:1100px){
  .hero-inner{grid-template-columns:1fr;gap:44px;text-align:center}
  .hero-desc{margin-left:auto;margin-right:auto}
  .hero h1{font-size:38px}
  .pick-list{grid-template-columns:repeat(3,1fr);max-width:420px}
  .grid4{grid-template-columns:repeat(2,1fr)}
  .sec-title{font-size:30px}
}
@media (max-width:900px){
  .nav-menu{display:none}
  .nav-download{margin-left:auto}
  .split{grid-template-columns:1fr;gap:36px}
  .split.reverse .split-media{order:0}
  .split-media img{max-width:420px}
  .vs{grid-template-columns:1fr;gap:20px}
  .vs-badge{justify-self:center}
}
@media (max-width:768px){
  .wrap{padding:0 20px}
  .sec{padding:64px 0}
  .hero{padding:112px 0 60px}
  .hero h1{font-size:32px}
  .hero-btn{width:100%;max-width:340px}
  .grid3{grid-template-columns:1fr}
  .cmp-scroll{margin-top:32px}
  .cmp{min-width:640px}
  .cmp-hint{display:block}
  .scene-list{grid-template-columns:1fr;margin-top:32px}
  .dl-meta{font-size:12px}
  .dl-btns{flex-direction:column;align-items:center;gap:14px}
  .dl-btn{width:100%;max-width:360px}
  .to-top{right:20px;bottom:20px}
  .chat-body{min-height:260px}
}
@media (max-width:640px){
  .grid4{grid-template-columns:1fr}
  .sec-title{font-size:26px}
  .chat-body{min-height:220px}
  .pick-list{max-width:340px}
  .data-item .num{font-size:38px}
  .nav-inner{height:58px}
  .logo,.nav .btn-sm{min-height:44px;display:inline-flex;align-items:center}
  .chat-input input{font-size:16px}
  .vs-card h3{font-size:17px}
}