/* ============================================================
   PlanSpark AI — Stylesheet
   Modern overseas SaaS aesthetic · Bilingual · Responsive
   ============================================================ */

:root{
  --bg:#ffffff;
  --bg-alt:#f6f7fb;
  --bg-dark:#0b1020;
  --surface:#ffffff;
  --ink:#0d1326;
  --ink-soft:#525a78;
  --ink-faint:#8b92ac;
  --line:#e7e9f3;
  --line-soft:#f0f1f7;
  --brand:#6d5efc;
  --brand-2:#8b5cf6;
  --brand-ink:#4c3fd6;
  --brand-soft:#efeefe;
  --accent:#ff6b6b;
  --green:#22c55e;
  --amber:#f59e0b;
  --shadow-sm:0 1px 2px rgba(16,18,40,.06),0 1px 3px rgba(16,18,40,.05);
  --shadow:0 8px 24px -8px rgba(16,18,40,.12),0 4px 10px -6px rgba(16,18,40,.06);
  --shadow-lg:0 30px 60px -20px rgba(16,18,40,.22),0 12px 24px -12px rgba(16,18,40,.10);
  --radius:16px;
  --radius-lg:24px;
  --container:1160px;
  --font:"Inter",-apple-system,BlinkMacSystemFont,"Segoe UI",Roboto,"Helvetica Neue",Arial,sans-serif;
}

*{box-sizing:border-box;margin:0;padding:0}
html{scroll-behavior:smooth;-webkit-text-size-adjust:100%}
body{
  font-family:var(--font);
  color:var(--ink);
  background:var(--bg);
  line-height:1.6;
  font-size:16px;
  -webkit-font-smoothing:antialiased;
  text-rendering:optimizeLegibility;
}
a{color:inherit;text-decoration:none}
img{max-width:100%;display:block}
button{font-family:inherit;cursor:pointer;border:none;background:none}
ul{list-style:none}

.container{width:100%;max-width:var(--container);margin:0 auto;padding:0 24px}

/* ============ BUTTONS ============ */
.btn{
  display:inline-flex;align-items:center;justify-content:center;gap:8px;
  font-weight:600;font-size:15px;
  padding:12px 20px;border-radius:12px;
  transition:transform .15s ease,box-shadow .2s ease,background .2s ease,color .2s ease;
  white-space:nowrap;letter-spacing:-.01em;
}
.btn:active{transform:translateY(1px)}
.btn-sm{padding:9px 16px;font-size:14px;border-radius:10px}
.btn-lg{padding:15px 26px;font-size:16px;border-radius:14px}
.btn-block{width:100%}
.btn-primary{
  background:linear-gradient(135deg,var(--brand) 0%,var(--brand-2) 100%);
  color:#fff;box-shadow:0 8px 20px -6px rgba(109,94,252,.5);
}
.btn-primary:hover{transform:translateY(-2px);box-shadow:0 14px 28px -8px rgba(109,94,252,.6)}
.btn-ghost{
  background:var(--surface);color:var(--ink);
  border:1.5px solid var(--line);box-shadow:var(--shadow-sm);
}
.btn-ghost:hover{border-color:var(--brand);color:var(--brand-ink)}
.btn .arrow{transition:transform .2s ease}
.btn:hover .arrow{transform:translateX(3px)}

/* ============ NAV ============ */
.nav{
  position:sticky;top:0;z-index:50;
  background:rgba(255,255,255,.8);
  backdrop-filter:saturate(180%) blur(16px);
  -webkit-backdrop-filter:saturate(180%) blur(16px);
  border-bottom:1px solid transparent;
  transition:border-color .2s ease,background .2s ease;
}
.nav.scrolled{border-color:var(--line)}
.nav-inner{display:flex;align-items:center;justify-content:space-between;height:68px}
.brand{display:inline-flex;align-items:center;gap:8px;font-weight:800;font-size:19px;letter-spacing:-.02em}
.brand-mark{font-size:20px}
.brand-accent{color:var(--brand)}
.nav-links{display:flex;gap:30px}
.nav-links a{font-size:14.5px;color:var(--ink-soft);font-weight:500;transition:color .15s}
.nav-links a:hover{color:var(--brand-ink)}
.nav-actions{display:flex;align-items:center;gap:12px}
.lang-toggle{
  width:42px;height:36px;border-radius:9px;
  border:1.5px solid var(--line);background:var(--surface);
  font-weight:700;font-size:13px;color:var(--brand-ink);
  transition:border-color .15s,background .15s;
}
.lang-toggle:hover{border-color:var(--brand);background:var(--brand-soft)}

/* ============ HERO ============ */
.hero{
  position:relative;overflow:hidden;
  padding:80px 0 90px;
  background:
    radial-gradient(1200px 500px at 80% -10%,rgba(139,92,246,.18),transparent 60%),
    radial-gradient(900px 400px at 10% 10%,rgba(109,94,252,.12),transparent 55%),
    linear-gradient(180deg,#fbfaff 0%,#ffffff 70%);
}
.hero-bg{
  position:absolute;inset:0;pointer-events:none;
  background-image:
    linear-gradient(rgba(109,94,252,.04) 1px,transparent 1px),
    linear-gradient(90deg,rgba(109,94,252,.04) 1px,transparent 1px);
  background-size:48px 48px;
  mask-image:radial-gradient(ellipse 80% 60% at 50% 0%,#000 30%,transparent 75%);
  -webkit-mask-image:radial-gradient(ellipse 80% 60% at 50% 0%,#000 30%,transparent 75%);
}
.hero-inner{position:relative;text-align:center;max-width:880px;margin:0 auto}
.hero-badge{
  display:inline-flex;align-items:center;gap:8px;
  padding:7px 14px;border-radius:999px;
  background:rgba(109,94,252,.08);color:var(--brand-ink);
  border:1px solid rgba(109,94,252,.18);
  font-size:13px;font-weight:600;margin-bottom:26px;
}
.pulse-dot{
  width:8px;height:8px;border-radius:50%;background:var(--green);
  box-shadow:0 0 0 0 rgba(34,197,94,.5);animation:pulse 2s infinite;
}
@keyframes pulse{
  0%{box-shadow:0 0 0 0 rgba(34,197,94,.5)}
  70%{box-shadow:0 0 0 8px rgba(34,197,94,0)}
  100%{box-shadow:0 0 0 0 rgba(34,197,94,0)}
}
.hero-title{
  font-size:clamp(34px,5.4vw,60px);line-height:1.08;font-weight:800;
  letter-spacing:-.03em;color:var(--ink);margin-bottom:22px;
}
.hero-sub{
  font-size:clamp(16px,2vw,19px);color:var(--ink-soft);
  max-width:680px;margin:0 auto 34px;line-height:1.65;
}
.hero-cta{display:flex;flex-direction:column;align-items:center;gap:14px}
.hero-micro{font-size:13.5px;color:var(--ink-faint);font-weight:500}
.hero-stats{
  display:flex;justify-content:center;gap:48px;margin-top:54px;
  padding-top:34px;border-top:1px solid var(--line-soft);
}
.stat{display:flex;flex-direction:column;align-items:center;gap:4px}
.stat strong{font-size:28px;font-weight:800;color:var(--ink);letter-spacing:-.02em}
.stat span{font-size:13px;color:var(--ink-faint);font-weight:500}

/* ============ SECTIONS ============ */
.section{padding:90px 0}
.section-alt{background:var(--bg-alt)}
.section-head{max-width:680px;margin:0 auto 56px;text-align:center}
.eyebrow{
  display:inline-block;font-size:13px;font-weight:700;letter-spacing:.06em;
  text-transform:uppercase;color:var(--brand);margin-bottom:14px;
}
.section-title{
  font-size:clamp(28px,3.6vw,40px);font-weight:800;letter-spacing:-.025em;
  line-height:1.15;margin-bottom:14px;
}
.section-desc{font-size:17px;color:var(--ink-soft);line-height:1.6}

/* ============ FEATURES ============ */
.features-grid{display:grid;grid-template-columns:repeat(3,1fr);gap:24px}
.feature-card{
  background:var(--surface);border:1px solid var(--line);border-radius:var(--radius-lg);
  padding:32px 28px;box-shadow:var(--shadow-sm);
  transition:transform .25s ease,box-shadow .25s ease,border-color .25s;
  position:relative;overflow:hidden;
}
.feature-card::before{
  content:"";position:absolute;left:0;top:0;bottom:0;width:4px;
  background:linear-gradient(180deg,var(--brand),var(--brand-2));
  opacity:0;transition:opacity .25s;
}
.feature-card:hover{transform:translateY(-4px);box-shadow:var(--shadow);border-color:transparent}
.feature-card:hover::before{opacity:1}
.feature-icon{
  width:54px;height:54px;border-radius:14px;display:flex;align-items:center;justify-content:center;
  font-size:26px;margin-bottom:18px;
}
.icon-1{background:#eef1ff;color:#5546e5}
.icon-2{background:#e8f9f0;color:#15a875}
.icon-3{background:#fff1e6;color:#e07b1a}
.feature-card h3{font-size:19px;font-weight:700;margin-bottom:8px;letter-spacing:-.01em}
.feature-kicker{font-size:14px;font-weight:600;color:var(--brand-ink);margin-bottom:10px}
.feature-card p{font-size:14.5px;color:var(--ink-soft);line-height:1.6}

/* ============ STAGES TRACK ============ */
.stages-track{
  display:grid;grid-template-columns:repeat(6,1fr);gap:14px;
  counter-reset:stage;
}
.stage-step{
  background:var(--surface);border:1px solid var(--line);border-radius:var(--radius);
  padding:22px 18px;position:relative;transition:transform .2s,box-shadow .2s;
}
.stage-step:hover{transform:translateY(-3px);box-shadow:var(--shadow)}
.stage-num{
  width:32px;height:32px;border-radius:9px;display:flex;align-items:center;justify-content:center;
  font-weight:800;font-size:15px;margin-bottom:14px;
}
.stage-step.free .stage-num{background:var(--brand-soft);color:var(--brand-ink)}
.stage-step.locked .stage-num{background:#f0f1f7;color:var(--ink-faint)}
.stage-body h4{font-size:15px;font-weight:700;margin-bottom:6px;letter-spacing:-.01em}
.stage-body p{font-size:13px;color:var(--ink-soft);line-height:1.5;margin-bottom:12px}
.tag{display:inline-block;font-size:11px;font-weight:700;padding:3px 9px;border-radius:6px;letter-spacing:.02em}
.tag-free{background:rgba(34,197,94,.12);color:#15803d}
.tag-pro{background:rgba(245,158,11,.14);color:#b45309}

/* ============ PRICING ============ */
.pricing-grid{display:grid;grid-template-columns:1fr 1fr;gap:24px;max-width:820px;margin:0 auto}
.price-card{
  background:var(--surface);border:1.5px solid var(--line);border-radius:var(--radius-lg);
  padding:36px 32px;position:relative;box-shadow:var(--shadow-sm);
}
.price-card-pro{
  border-color:var(--brand);box-shadow:0 20px 50px -16px rgba(109,94,252,.4);
  background:linear-gradient(180deg,#fff 0%,#fbfaff 100%);
}
.price-flag{
  position:absolute;top:-13px;left:50%;transform:translateX(-50%);
  background:linear-gradient(135deg,var(--brand),var(--brand-2));color:#fff;
  font-size:12px;font-weight:700;padding:5px 14px;border-radius:999px;letter-spacing:.02em;
}
.price-head{margin-bottom:24px;padding-bottom:22px;border-bottom:1px solid var(--line-soft)}
.price-head h3{font-size:19px;font-weight:700;margin-bottom:14px}
.price-amount{display:flex;align-items:baseline;gap:2px}
.price-amount .cur{font-size:22px;font-weight:700;color:var(--ink-soft)}
.price-amount .amt{font-size:48px;font-weight:800;letter-spacing:-.03em;line-height:1}
.price-amount .per{font-size:16px;color:var(--ink-faint);font-weight:500;margin-left:4px}
.price-bill{font-size:13px;color:var(--ink-faint);margin-top:6px}
.price-list{margin-bottom:26px;display:flex;flex-direction:column;gap:13px}
.price-list li{
  font-size:14.5px;color:var(--ink-soft);padding-left:26px;position:relative;line-height:1.5;
}
.price-list li::before{
  content:"✓";position:absolute;left:0;top:0;color:var(--green);font-weight:800;font-size:14px;
}
.price-card-pro .price-list li::before{color:var(--brand)}

/* ============ FOOTER ============ */
.footer{padding:48px 0 40px;border-top:1px solid var(--line);background:var(--bg-alt)}
.footer-inner{text-align:center;display:flex;flex-direction:column;align-items:center;gap:10px}
.footer-tag{font-size:14px;color:var(--ink-soft);font-style:italic}
.footer-copy{font-size:12.5px;color:var(--ink-faint)}

/* ============ CHAT OVERLAY ============ */
.chat-overlay{
  position:fixed;inset:0;z-index:100;
  background:rgba(11,16,32,.55);backdrop-filter:blur(6px);
  display:flex;align-items:center;justify-content:center;padding:24px;
  opacity:0;visibility:hidden;transition:opacity .25s,visibility .25s;
}
.chat-overlay.open{opacity:1;visibility:visible}
.chat-shell{
  width:100%;max-width:780px;height:min(720px,90vh);
  background:var(--surface);border-radius:var(--radius-lg);
  box-shadow:var(--shadow-lg);display:flex;flex-direction:row;overflow:hidden;
  transform:translateY(20px) scale(.98);transition:transform .3s ease;
}
.chat-overlay.open .chat-shell{transform:translateY(0) scale(1)}

/* sidebar (vertical stage tree) */
.chat-sidebar{
  width:210px;flex-shrink:0;display:flex;flex-direction:column;
  background:linear-gradient(180deg,#0f1330 0%,#161a3d 100%);color:#cdd2f5;
  padding:20px 16px;overflow-y:auto;
}
.chat-sidebar::-webkit-scrollbar{width:5px}
.chat-sidebar::-webkit-scrollbar-thumb{background:rgba(255,255,255,.14);border-radius:999px}
.sidebar-head{display:flex;align-items:center;gap:8px;margin-bottom:4px}
.sidebar-head .brand-mark{font-size:18px}
.sidebar-brand{font-weight:800;font-size:16px;color:#fff;letter-spacing:-.01em}
.sidebar-brand .brand-accent{color:#a5b4ff}
.sidebar-label{
  font-size:10.5px;font-weight:700;letter-spacing:.08em;text-transform:uppercase;
  color:#7e85b8;margin:18px 4px 12px;
}
.stage-tree{flex:1;display:flex;flex-direction:column;position:relative}
.stage-node{
  display:flex;gap:11px;padding:7px 0;position:relative;cursor:default;
  transition:transform .2s ease;
}
/* vertical connector line */
.stage-node::before{
  content:"";position:absolute;left:13px;top:24px;bottom:-7px;width:2px;
  background:rgba(255,255,255,.12);
}
.stage-node:last-child::before{display:none}
.stage-node.done::before{background:linear-gradient(180deg,var(--green),rgba(255,255,255,.12))}
.stage-node.active::before{background:linear-gradient(180deg,var(--brand-2),rgba(255,255,255,.12))}
.sn-dot{
  width:26px;height:26px;border-radius:50%;flex-shrink:0;
  display:flex;align-items:center;justify-content:center;
  font-size:12px;font-weight:800;position:relative;z-index:1;
  background:#1e2350;color:#7e85b8;border:2px solid rgba(255,255,255,.12);
  transition:all .25s ease;
}
.stage-node.done .sn-dot{background:var(--green);border-color:var(--green);color:#fff}
.stage-node.active .sn-dot{
  background:linear-gradient(135deg,var(--brand),var(--brand-2));border-color:#a5b4ff;color:#fff;
  box-shadow:0 0 0 4px rgba(109,94,252,.25);
}
.sn-body{flex:1;min-width:0;padding-top:2px}
.sn-title{font-size:12.5px;font-weight:600;color:#9aa0d0;line-height:1.3;transition:color .2s}
.stage-node.done .sn-title{color:#b8bee6}
.stage-node.active .sn-title{color:#fff;font-weight:700}
.sn-tag{
  display:inline-block;font-size:9.5px;font-weight:700;margin-top:3px;padding:1px 6px;border-radius:4px;letter-spacing:.02em;
}
.sn-tag.free{background:rgba(34,197,94,.18);color:#86efac}
.sn-tag.pro{background:rgba(245,158,11,.18);color:#fcd34d}
.sn-tag.locked{background:rgba(255,255,255,.08);color:#7e85b8}
.sidebar-foot{margin-top:14px;padding-top:14px;border-top:1px solid rgba(255,255,255,.1)}
.sidebar-progress{display:flex;align-items:center;gap:8px}
.sp-track{flex:1;height:5px;background:rgba(255,255,255,.12);border-radius:999px;overflow:hidden}
.sp-fill{height:100%;width:0;background:linear-gradient(90deg,var(--brand),var(--brand-2));border-radius:999px;transition:width .4s ease}
.sp-pct{font-size:11px;font-weight:700;color:#a5b4ff;min-width:30px;text-align:right}

/* main chat column */
.chat-main{flex:1;min-width:0;display:flex;flex-direction:column}
.chat-topbar{
  display:flex;align-items:center;justify-content:space-between;
  padding:12px 18px;border-bottom:1px solid var(--line);
  background:linear-gradient(135deg,var(--brand) 0%,var(--brand-2) 100%);color:#fff;
}
.chat-brand{display:flex;align-items:center;gap:10px;font-weight:700;font-size:15px}
.chat-brand .brand-mark{font-size:18px}
.chat-status{display:inline-flex;align-items:center;gap:6px;font-size:12px;font-weight:500;opacity:.9}
.chat-status .pulse-dot{background:#7ef3a8}
.chat-top-actions{display:flex;gap:6px}
.icon-btn{
  width:32px;height:32px;border-radius:8px;color:#fff;font-size:16px;
  display:flex;align-items:center;justify-content:center;opacity:.85;transition:opacity .15s,background .15s;
}
.icon-btn:hover{opacity:1;background:rgba(255,255,255,.18)}

/* body */
.chat-body{flex:1;overflow-y:auto;padding:24px 20px;display:flex;flex-direction:column;gap:14px;scroll-behavior:smooth}
.chat-body::-webkit-scrollbar{width:6px}
.chat-body::-webkit-scrollbar-thumb{background:var(--line);border-radius:999px}
.msg{display:flex;gap:10px;max-width:88%;animation:msgIn .35s ease}
@keyframes msgIn{from{opacity:0;transform:translateY(8px)}to{opacity:1;transform:translateY(0)}}
.msg.ai{align-self:flex-start}
.msg.user{align-self:flex-end;flex-direction:row-reverse}
.msg-avatar{
  width:30px;height:30px;border-radius:8px;flex-shrink:0;
  display:flex;align-items:center;justify-content:center;font-size:15px;
}
.msg.ai .msg-avatar{background:linear-gradient(135deg,var(--brand),var(--brand-2));color:#fff}
.msg.user .msg-avatar{background:var(--ink);color:#fff;font-size:13px;font-weight:700}
.msg-bubble{
  padding:11px 15px;border-radius:14px;font-size:14.5px;line-height:1.55;
}
.msg.ai .msg-bubble{background:var(--bg-alt);color:var(--ink);border-bottom-left-radius:4px}
.msg.user .msg-bubble{background:linear-gradient(135deg,var(--brand),var(--brand-2));color:#fff;border-bottom-right-radius:4px}
.msg-bubble strong{font-weight:700}
.msg-bubble em{font-style:italic;color:var(--ink-faint)}
.msg.user .msg-bubble em{color:rgba(255,255,255,.8)}
.msg-bubble .hint{display:block;margin-top:8px;padding-top:8px;border-top:1px dashed var(--line);font-size:13px;color:var(--ink-faint)}
.msg.user .msg-bubble .hint{border-top-color:rgba(255,255,255,.25)}
.typing{display:inline-flex;gap:4px;padding:4px 0}
.typing span{width:7px;height:7px;border-radius:50%;background:var(--ink-faint);animation:typing 1.2s infinite}
.typing span:nth-child(2){animation-delay:.2s}
.typing span:nth-child(3){animation-delay:.4s}
@keyframes typing{0%,60%,100%{opacity:.3;transform:translateY(0)}30%{opacity:1;transform:translateY(-3px)}}

/* input */
.chat-input-wrap{padding:14px 20px 18px;border-top:1px solid var(--line);background:var(--surface)}
.chat-quick{display:flex;flex-wrap:wrap;gap:8px;margin-bottom:10px}
.chat-quick:empty{display:none}
.quick-chip{
  font-size:12.5px;padding:6px 12px;border-radius:999px;
  background:var(--brand-soft);color:var(--brand-ink);font-weight:600;
  border:1px solid rgba(109,94,252,.18);transition:background .15s,transform .1s;
}
.quick-chip:hover{background:#e3deff}
.quick-chip:active{transform:scale(.96)}
.chat-input-row{display:flex;gap:10px;align-items:flex-end}
.chat-input{
  flex:1;resize:none;border:1.5px solid var(--line);border-radius:12px;
  padding:11px 14px;font-size:14.5px;font-family:inherit;line-height:1.5;
  max-height:120px;transition:border-color .15s;outline:none;background:var(--bg-alt);
}
.chat-input:focus{border-color:var(--brand);background:#fff}
.btn-send{padding:11px 18px;border-radius:12px}
.chat-hint{font-size:12px;color:var(--ink-faint);margin-top:8px;text-align:center;min-height:16px}

/* ============ MODALS ============ */
.modal-overlay{
  position:fixed;inset:0;z-index:110;background:rgba(11,16,32,.6);backdrop-filter:blur(8px);
  display:flex;align-items:center;justify-content:center;padding:24px;
  opacity:0;visibility:hidden;transition:opacity .25s,visibility .25s;
}
.modal-overlay.open{opacity:1;visibility:visible}
.modal{
  background:#fff;border-radius:var(--radius-lg);box-shadow:var(--shadow-lg);
  width:100%;max-width:460px;padding:36px 34px;position:relative;
  transform:translateY(16px) scale(.97);transition:transform .3s ease;
  max-height:90vh;overflow-y:auto;
}
.modal-overlay.open .modal{transform:translateY(0) scale(1)}
.modal-close{
  position:absolute;top:14px;right:14px;width:32px;height:32px;border-radius:8px;
  color:var(--ink-faint);font-size:16px;display:flex;align-items:center;justify-content:center;
  transition:background .15s,color .15s;
}
.modal-close:hover{background:var(--bg-alt);color:var(--ink)}
.modal::-webkit-scrollbar{width:6px}
.modal::-webkit-scrollbar-thumb{background:var(--line);border-radius:999px}

/* paywall */
.paywall{text-align:center}
.paywall-icon{font-size:44px;margin-bottom:14px}
.paywall-title{font-size:23px;font-weight:800;letter-spacing:-.02em;margin-bottom:10px}
.paywall-sub{font-size:14.5px;color:var(--ink-soft);line-height:1.6;margin-bottom:20px}
.paywall-unlock{font-size:13.5px;font-weight:700;color:var(--ink);margin-bottom:12px}
.paywall-list{display:flex;flex-direction:column;gap:8px;margin-bottom:22px;text-align:left}
.paywall-list li{
  font-size:13.5px;color:var(--ink-soft);padding:10px 14px;background:var(--bg-alt);
  border-radius:10px;border-left:3px solid var(--brand);
}
.paywall-price{display:flex;align-items:baseline;justify-content:center;gap:4px;margin-bottom:22px}
.po-cur{font-size:20px;font-weight:700;color:var(--ink-soft)}
.po-amt{font-size:46px;font-weight:800;letter-spacing:-.03em}
.po-per{font-size:16px;color:var(--ink-faint);font-weight:500}
.po-bill{font-size:13px;color:var(--ink-faint);margin-left:10px}
.paywall-fine{font-size:12px;color:var(--ink-faint);margin-top:14px}

/* —— 功能A 邮箱收集 modal —— */
.email-modal{text-align:center;max-width:420px}
.email-icon{font-size:42px;margin-bottom:14px}
.email-title{font-size:21px;font-weight:800;letter-spacing:-.02em;margin-bottom:10px}
.email-sub{font-size:14px;color:var(--ink-soft);line-height:1.6;margin-bottom:20px}
.btn-skip{
  display:block;width:100%;margin-top:10px;padding:8px;
  font-size:13px;color:var(--ink-faint);background:none;cursor:pointer;
  transition:color .15s;
}
.btn-skip:hover{color:var(--ink-soft)}

/* —— 功能B 付费墙 plan 选择 —— */
.paywall-plans{display:grid;grid-template-columns:1fr 1fr;gap:12px;margin-bottom:20px}
.plan-option{cursor:pointer;display:block}
.plan-option input{position:absolute;opacity:0;pointer-events:none}
.plan-card{
  position:relative;padding:16px 12px 14px;border-radius:14px;
  border:1.5px solid var(--line);background:var(--surface);
  text-align:center;transition:border-color .18s,box-shadow .18s,background .18s;
}
.plan-option input:checked + .plan-card{
  border-color:var(--brand);background:var(--brand-soft);
  box-shadow:0 8px 20px -8px rgba(109,94,252,.28);
}
.plan-card-best{border-color:var(--brand-2)}
.plan-flag{
  position:absolute;top:-9px;left:50%;transform:translateX(-50%);
  background:linear-gradient(135deg,var(--brand) 0%,var(--brand-2) 100%);color:#fff;
  font-size:10px;font-weight:700;letter-spacing:.04em;text-transform:uppercase;
  padding:3px 10px;border-radius:999px;white-space:nowrap;
}
.plan-name{font-size:13px;font-weight:700;color:var(--ink-soft);margin-bottom:6px}
.plan-price{display:flex;align-items:baseline;justify-content:center;gap:2px;margin-bottom:4px}
.plan-price .cur{font-size:14px;font-weight:700;color:var(--ink-soft)}
.plan-price .amt{font-size:30px;font-weight:800;letter-spacing:-.02em;color:var(--ink)}
.plan-price .per{font-size:12px;color:var(--ink-faint)}
.plan-note{font-size:11px;color:var(--ink-faint)}
@media(max-width:480px){
  .paywall-plans{grid-template-columns:1fr;gap:14px}
}

/* stripe mock */
.stripe-modal{max-width:420px}
.stripe-brand{font-size:26px;font-weight:800;color:#635bff;letter-spacing:-.02em;margin-bottom:6px;font-style:italic}
.stripe-title{font-size:19px;font-weight:700;margin-bottom:18px}
.stripe-price{display:flex;align-items:baseline;gap:4px;margin-bottom:22px;padding-bottom:18px;border-bottom:1px solid var(--line)}
.stripe-price .cur{font-size:18px;font-weight:700;color:var(--ink-soft)}
.stripe-price .amt{font-size:34px;font-weight:800;letter-spacing:-.02em}
.stripe-price .per{font-size:15px;color:var(--ink-faint)}
.stripe-field{display:block;margin-bottom:14px}
.stripe-field span{display:block;font-size:12px;font-weight:600;color:var(--ink-soft);margin-bottom:6px}
.stripe-field input{
  width:100%;padding:11px 13px;font-size:14.5px;font-family:inherit;
  border:1.5px solid var(--line);border-radius:10px;outline:none;transition:border-color .15s;
}
.stripe-field input:focus{border-color:var(--brand)}
.stripe-row{display:grid;grid-template-columns:1fr 1fr;gap:12px}

/* canvas */
.canvas-modal{max-width:920px;padding:30px}
.canvas-head{display:flex;align-items:center;justify-content:space-between;margin-bottom:22px;padding-right:36px}
.canvas-head h3{font-size:22px;font-weight:800;letter-spacing:-.02em}
.canvas-actions{display:flex;gap:8px}
.canvas-grid{
  display:grid;grid-template-columns:repeat(3,1fr);grid-template-rows:auto auto auto;
  gap:12px;
}
.canvas-box{
  background:var(--bg-alt);border:1px solid var(--line);border-radius:14px;
  padding:18px 16px;position:relative;min-height:130px;
}
.canvas-box.span-2{grid-column:span 2}
.canvas-box .cb-tag{
  font-size:10.5px;font-weight:700;letter-spacing:.05em;text-transform:uppercase;
  color:var(--brand);margin-bottom:8px;display:flex;align-items:center;gap:6px;
}
.canvas-box .cb-tag .num{
  width:18px;height:18px;border-radius:5px;background:var(--brand-soft);color:var(--brand-ink);
  display:inline-flex;align-items:center;justify-content:center;font-size:11px;
}
.canvas-box h5{font-size:14px;font-weight:700;margin-bottom:8px}
.canvas-box .cb-content{font-size:12.5px;color:var(--ink-soft);line-height:1.55;white-space:pre-wrap}
.canvas-box.locked{position:relative}
.canvas-box.locked .cb-content{filter:blur(5px);opacity:.5;user-select:none}
.canvas-box.locked::after{
  content:"🔒";position:absolute;top:50%;left:50%;transform:translate(-50%,-50%);
  font-size:24px;opacity:.7;
}

/* ============ RESPONSIVE ============ */
@media (max-width:900px){
  .features-grid{grid-template-columns:1fr}
  .stages-track{grid-template-columns:repeat(2,1fr)}
  .pricing-grid{grid-template-columns:1fr}
  .nav-links{display:none}
  .hero-stats{gap:28px}
  .canvas-grid{grid-template-columns:1fr 1fr}
  .canvas-box.span-2{grid-column:span 2}
}
@media (max-width:560px){
  .container{padding:0 18px}
  .hero{padding:54px 0 60px}
  .section{padding:64px 0}
  .hero-stats{flex-wrap:wrap;gap:20px}
  .stages-track{grid-template-columns:1fr}
  .canvas-grid{grid-template-columns:1fr}
  .canvas-box.span-2{grid-column:span 1}
  .chat-shell{height:100vh;max-height:100vh;border-radius:0;max-width:100%}
  /* collapse sidebar into a slim rail on phones to preserve chat width */
  .chat-sidebar{width:64px;padding:16px 8px}
  .sidebar-brand,.sidebar-label,.sn-title,.sn-tag,.sidebar-foot{display:none}
  .stage-node{justify-content:center;padding:6px 0}
  .stage-node::before{left:50%;transform:translateX(-50%)}
  .sn-dot{width:24px;height:24px}
  .modal{padding:28px 22px}
  .price-card{padding:28px 24px}
}