/* Naturalingo Landing — Indigo theme matching AppColors */
*,*::before,*::after{box-sizing:border-box;margin:0;padding:0}
:root{
  --primary:#6366F1;--primary-light:#818CF8;--primary-dark:#4F46E5;
  --primary-deep:#1D4ED8;--primary-container:#3730A3;
  --emerald:#10B981;--emerald-dark:#059669;--emerald-light:#D1FAE5;
  --red:#EF4444;--red-light:#FEE2E2;
  --amber:#F59E0B;
  --text:#1F2937;--text2:#6B7280;--text3:#9CA3AF;
  --bg:#F9FAFB;--card:#fff;--border:#E5E7EB;--border2:#D1D5DB;
  --slate800:#1E293B;--slate900:#0F172A;
  --font:'DM Sans',system-ui,-apple-system,sans-serif;
}
html{scroll-behavior:smooth;-webkit-font-smoothing:antialiased}
body{font-family:var(--font);color:var(--text);background:var(--bg);overflow-x:hidden;line-height:1.6}
img{display:block}a{color:inherit;text-decoration:none}
.container{max-width:960px;margin:0 auto;padding:0 20px}

/* Fade */
.fade-in{opacity:0;transform:translateY(18px);transition:opacity .5s,transform .5s}
.fade-in.visible{opacity:1;transform:translateY(0)}

/* NAV */
.nav{position:sticky;top:0;z-index:100;background:rgba(249,250,251,.88);backdrop-filter:blur(14px);-webkit-backdrop-filter:blur(14px);border-bottom:1px solid var(--border);transition:box-shadow .3s}
.nav.scrolled{box-shadow:0 2px 10px rgba(0,0,0,.06)}
.nav-inner{max-width:960px;margin:0 auto;padding:10px 20px;display:flex;align-items:center;justify-content:space-between}
.nav-logo{display:flex;align-items:center;gap:8px}
.nav-logo-icon{width:28px;height:28px;border-radius:7px;background:var(--primary);display:flex;align-items:center;justify-content:center}
.nav-logo-text{font-size:16px;font-weight:700;letter-spacing:-.4px}
.btn-nav{background:var(--primary);color:#fff;border-radius:100px;padding:8px 18px;font-size:13px;font-weight:600;font-family:var(--font);border:none;cursor:pointer;transition:background .2s}
.btn-nav:hover{background:var(--primary-dark)}

/* PILL */
.pill{display:inline-flex;align-items:center;gap:6px;padding:5px 13px;border-radius:100px;font-size:12px;font-weight:600;background:#EEF2FF;color:var(--primary-dark);letter-spacing:.2px}
.pill-dot{width:6px;height:6px;border-radius:50%;background:var(--primary);animation:pulse 2s infinite}
@keyframes pulse{0%,100%{opacity:1}50%{opacity:.3}}

/* STORE BUTTONS */
.store-row{display:flex;gap:10px;flex-wrap:wrap;justify-content:center}
.store-row-center{justify-content:center}
.store-btn{display:inline-flex;align-items:center;gap:9px;padding:10px 18px;background:var(--slate800);color:#fff;border-radius:10px;transition:transform .2s,box-shadow .2s;min-width:150px}
.store-btn:hover{transform:translateY(-1px);box-shadow:0 4px 14px rgba(0,0,0,.12)}
.store-btn svg{flex-shrink:0}
.store-label{display:block;font-size:9px;opacity:.7;line-height:1.2}
.store-name{display:block;font-size:14px;font-weight:700;line-height:1.2}
.store-btn-light{background:#fff;color:var(--text);border:1px solid var(--border)}
.store-btn-light:hover{border-color:var(--primary);box-shadow:0 4px 14px rgba(99,102,241,.12)}

/* HERO */
.hero{padding:48px 0 36px}
.hero-center{text-align:center}
.hero-title{font-size:clamp(28px,6vw,44px);font-weight:800;line-height:1.08;letter-spacing:-1.2px;margin:14px 0}
.hero-muted{color:var(--text3)}
.hero-sub{font-size:16px;color:var(--text2);line-height:1.6;max-width:500px;margin:0 auto 24px}

/* SECTION HEADINGS */
.section-head{text-align:center;margin-bottom:28px}
.section-title{font-size:clamp(24px,4vw,32px);font-weight:800;letter-spacing:-.7px;line-height:1.15}
.section-sub{font-size:15px;color:var(--text2);margin-top:6px;max-width:460px;margin-left:auto;margin-right:auto;line-height:1.5}

/* LANG SELECTOR */
.lang-selector{display:flex;align-items:flex-end;justify-content:center;gap:14px;margin-bottom:28px;flex-wrap:wrap}
.lang-pick{display:flex;flex-direction:column;gap:4px}
.lang-label{font-size:11px;font-weight:600;color:var(--text2);text-transform:uppercase;letter-spacing:.3px}
.lang-select{padding:8px 12px;border:1px solid var(--border);border-radius:8px;font-size:14px;font-family:var(--font);font-weight:500;color:var(--text);background:var(--card);cursor:pointer;outline:none;min-width:150px}
.lang-select:focus{border-color:var(--primary);box-shadow:0 0 0 3px rgba(99,102,241,.12)}
.btn-replay{display:inline-flex;align-items:center;gap:5px;padding:8px 14px;border:1px solid var(--border);border-radius:8px;font-size:13px;font-weight:600;font-family:var(--font);color:var(--text2);background:var(--card);cursor:pointer;transition:border-color .2s}
.btn-replay:hover{border-color:var(--primary);color:var(--primary)}
.btn-replay svg{flex-shrink:0}

/* DUAL PHONES */
.phones{display:flex;align-items:flex-start;justify-content:center;gap:20px}
.phone{flex:1;max-width:320px;background:var(--card);border-radius:20px;border:1px solid var(--border);overflow:hidden;box-shadow:0 6px 24px rgba(0,0,0,.07);min-height:420px;display:flex;flex-direction:column}
.phone-top{display:flex;align-items:center;gap:9px;padding:11px 14px;border-bottom:1px solid var(--border);background:var(--bg)}
.phone-top-friend{background:#EEF2FF}
.phone-av{width:30px;height:30px;border-radius:50%;display:flex;align-items:center;justify-content:center;font-size:11px;font-weight:700;color:#fff;flex-shrink:0}
.phone-name{font-size:13px;font-weight:600;margin:0;line-height:1.2}
.phone-lang{font-size:10px;color:var(--text3);margin:1px 0 0}
.phone-body{flex:1;padding:12px;display:flex;flex-direction:column;gap:10px;overflow-y:auto;max-height:520px}

/* FLOW COLUMN */
.flow-col{display:flex;flex-direction:column;align-items:center;justify-content:center;gap:18px;width:120px;flex-shrink:0;padding:30px 0}
.flow-step{text-align:center;opacity:.25;transform:scale(.92);transition:opacity .4s,transform .4s}
.flow-step.active{opacity:1;transform:scale(1)}
.flow-num{width:28px;height:28px;border-radius:50%;background:var(--primary);color:#fff;display:inline-flex;align-items:center;justify-content:center;font-size:12px;font-weight:800;margin-bottom:4px}
.flow-step p{font-size:11px;color:var(--text2);line-height:1.35;font-weight:500}

/* MESSAGE BUBBLES (injected by JS) */
.msg{display:flex;align-items:flex-end;gap:6px;opacity:0;transform:translateY(8px);transition:opacity .35s,transform .35s}
.msg.show{opacity:1;transform:translateY(0)}
.msg-sent{justify-content:flex-end}
.msg-av{width:24px;height:24px;border-radius:50%;display:flex;align-items:center;justify-content:center;font-size:9px;font-weight:700;color:#fff;flex-shrink:0}
.bub{max-width:85%;padding:9px 12px;font-size:13px;line-height:1.4}
.bub p{margin:0}
.bub-own{background:var(--primary);color:#fff;border-radius:16px 16px 4px 16px;box-shadow:0 2px 8px rgba(99,102,241,.3);border:1px solid rgba(255,255,255,.1)}
.bub-other{background:#F3F4F6;color:var(--text);border-radius:16px 16px 16px 4px;box-shadow:0 1px 4px rgba(0,0,0,.04);border:1px solid rgba(0,0,0,.04)}
.bub-time{display:block;margin-top:3px;font-size:9px;opacity:.5}

/* CORRECTION CARD (inside own bubble) */
.corr{margin-top:8px;padding:9px 10px;background:var(--primary-container);color:#E0E7FF;border-radius:12px 12px 12px 4px;border:1px solid rgba(99,102,241,.3);box-shadow:0 2px 6px rgba(99,102,241,.25);font-size:11px}
.corr-head{display:flex;align-items:center;gap:4px;font-weight:700;font-size:11px;color:#C7D2FE;margin-bottom:6px}
.corr-head svg{flex-shrink:0}
.corr-label{font-size:10px;font-weight:600;color:rgba(224,231,255,.7);margin-bottom:3px}
.corr-box{padding:6px 8px;background:rgba(99,102,241,.15);border:1px solid rgba(99,102,241,.22);border-radius:8px;font-size:12px;font-style:italic;color:#E0E7FF;line-height:1.4;margin-bottom:6px}
.corr-box b{font-weight:800;color:#A5B4FC;font-style:normal}
.corr-row{display:flex;align-items:flex-start;gap:4px;margin-top:4px;font-size:11px;line-height:1.35;color:rgba(224,231,255,.8)}
.corr-row .arrow{color:rgba(224,231,255,.45);flex-shrink:0;margin-top:1px}
.corr-err{text-decoration:line-through;font-weight:600;color:#FCA5A5}
.corr-fix{font-weight:800;color:#86EFAC}
.corr-explain{color:rgba(224,231,255,.6);font-size:10px}

/* Mixed word highlight in own bubble */
.mix{background:rgba(255,255,255,.18);padding:0 3px;border-radius:3px;border-bottom:1.5px dashed rgba(255,255,255,.45);font-weight:600}

/* ============ FLASHCARDS ============ */
.flashcards{padding:56px 0}
.fc-layout{display:grid;grid-template-columns:1fr 1fr;gap:40px;align-items:center}
.fc-desc{font-size:15px;color:var(--text2);line-height:1.6;margin:12px 0 18px}
.fc-list{list-style:none;display:flex;flex-direction:column;gap:10px}
.fc-list li{display:flex;align-items:center;gap:8px;font-size:14px;font-weight:500;color:var(--text)}
.fc-list li svg{flex-shrink:0}
.fc-visual{display:flex;justify-content:center}
.fc-stack{position:relative;width:230px;height:190px}
.fc-card{position:absolute;width:230px;padding:24px 20px;border-radius:14px;background:var(--card);border:1px solid var(--border);box-shadow:0 4px 16px rgba(0,0,0,.06);text-align:center}
.fc-front{top:16px;left:0;z-index:2;box-shadow:0 6px 20px rgba(0,0,0,.08)}
.fc-back{top:0;left:20px;z-index:1;opacity:.55;transform:rotate(3deg)}
.fc-flag{font-size:20px;margin-bottom:6px}
.fc-word{font-size:26px;font-weight:800;letter-spacing:-.4px;margin:0}
.fc-trans{font-size:14px;color:var(--primary);font-weight:600;margin:2px 0 0}
.fc-strength{height:4px;background:var(--border);border-radius:2px;margin:10px 0 8px;overflow:hidden}
.fc-bar{height:100%;background:var(--emerald);border-radius:2px}
.fc-source{font-size:10px;color:var(--text3);padding-top:8px;border-top:1px solid var(--border)}

/* ============ AI PERSONAS ============ */
.personas{padding:48px 0;background:var(--bg)}
.persona-grid{display:flex;gap:12px;justify-content:center;flex-wrap:wrap}
.persona-card{width:120px;background:var(--card);border:1px solid var(--border);border-radius:14px;padding:18px 12px;text-align:center;transition:transform .2s,box-shadow .2s}
.persona-card:hover{transform:translateY(-2px);box-shadow:0 4px 14px rgba(0,0,0,.07)}
.persona-av{width:44px;height:44px;border-radius:50%;display:inline-flex;align-items:center;justify-content:center;font-size:20px;margin-bottom:8px}
.persona-name{font-size:14px;font-weight:700;margin:0}
.persona-role{font-size:11px;color:var(--text2);margin:2px 0 0}

/* ============ CTA ============ */
.cta{padding:52px 0 60px}
.cta-center{text-align:center}
.cta-title{font-size:clamp(26px,5vw,36px);font-weight:800;letter-spacing:-.8px;margin-bottom:6px}
.cta-sub{font-size:16px;color:var(--text2);margin-bottom:24px}

/* ============ FOOTER ============ */
.footer{padding:16px;text-align:center;border-top:1px solid var(--border);font-size:12px;color:var(--text3)}

/* ============ RESPONSIVE ============ */
@media(max-width:820px){
  .phones{flex-direction:column;align-items:center}
  .phone{max-width:360px;width:100%;min-height:auto}
  .flow-col{flex-direction:row;width:auto;padding:10px 0;gap:12px}
  .flow-step p{font-size:10px}
  .fc-layout{grid-template-columns:1fr;text-align:center;gap:28px}
  .fc-list{align-items:center}
}
@media(max-width:500px){
  .hero-title{font-size:26px}
  .lang-selector{flex-direction:column;align-items:stretch;gap:10px}
  .lang-select{width:100%}
  .store-row{flex-direction:column;align-items:center}
  .store-btn{width:100%;justify-content:center}
  .persona-grid{gap:8px}
  .persona-card{width:100px;padding:14px 8px}
  .fc-stack{width:200px;height:170px}
  .fc-card{width:200px;padding:20px 16px}
  .fc-word{font-size:22px}
  .fc-back{left:14px}
}