/* ============================================================
   World AI Classroom — site stylesheet
   ============================================================ */
:root{
  --navy-900:#0B1228; --navy-800:#101A38; --navy-700:#182448;
  --ink:#0F172A; --slate:#475569; --slate-l:#94A3B8;
  --indigo:#4F46E5; --cyan:#06B6D4; --sky:#0EA5E9;
  --gold:#F59E0B; --gold-d:#D97706;
  --bg:#F6F8FC; --card:#FFFFFF; --line:#E2E8F0;
  --grad:linear-gradient(120deg,#4F46E5 0%,#0EA5E9 55%,#06B6D4 100%);
  --radius:18px;
  --shadow-sm:0 1px 3px rgba(15,23,42,.08);
  --shadow-md:0 10px 30px -10px rgba(15,23,42,.18);
  --shadow-lg:0 25px 60px -20px rgba(15,23,42,.3);
  --font:'Plus Jakarta Sans','Segoe UI',system-ui,Arial,sans-serif;
}
*{margin:0;padding:0;box-sizing:border-box}
html{scroll-behavior:smooth}
body{font-family:var(--font);color:var(--ink);background:var(--bg);line-height:1.65;
     -webkit-font-smoothing:antialiased;overflow-x:hidden}
img,svg{max-width:100%;vertical-align:middle}
a{color:var(--indigo);text-decoration:none}
.container{width:min(1160px,92%);margin-inline:auto}

h1,h2,h3,h4{line-height:1.18;font-weight:800;letter-spacing:-.02em}
h1{font-size:clamp(2.1rem,4.6vw,3.6rem)}
h2{font-size:clamp(1.7rem,3.2vw,2.5rem)}
h3{font-size:1.22rem}
.lead{font-size:clamp(1.02rem,1.6vw,1.22rem);color:var(--slate);max-width:46rem}
.grad-text{background:var(--grad);-webkit-background-clip:text;background-clip:text;color:transparent}
.eyebrow{display:inline-flex;align-items:center;gap:.5rem;font-size:.8rem;font-weight:700;
  letter-spacing:.14em;text-transform:uppercase;color:var(--indigo);
  background:rgba(79,70,229,.09);border:1px solid rgba(79,70,229,.22);
  padding:.38rem .9rem;border-radius:999px;margin-bottom:1.1rem}
.section{padding:clamp(3.5rem,7vw,6rem) 0}
.section-head{text-align:center;max-width:44rem;margin:0 auto clamp(2.2rem,4vw,3.4rem)}
.section-head .lead{margin:1rem auto 0}

/* ---------- buttons ---------- */
.btn{display:inline-flex;align-items:center;justify-content:center;gap:.55rem;
  font-family:var(--font);font-weight:700;font-size:1rem;cursor:pointer;border:0;
  padding:.85rem 1.7rem;border-radius:999px;transition:.25s;white-space:nowrap}
.btn-primary{background:var(--grad);color:#fff;box-shadow:0 10px 24px -8px rgba(14,165,233,.55)}
.btn-primary:hover{transform:translateY(-2px);box-shadow:0 16px 32px -8px rgba(14,165,233,.65)}
.btn-gold{background:linear-gradient(120deg,#F59E0B,#F97316);color:#fff;
  box-shadow:0 10px 24px -8px rgba(245,158,11,.55)}
.btn-gold:hover{transform:translateY(-2px)}
.btn-ghost{background:transparent;color:#fff;border:1.5px solid rgba(255,255,255,.35)}
.btn-ghost:hover{background:rgba(255,255,255,.1);border-color:rgba(255,255,255,.6)}
.btn-outline{background:#fff;color:var(--indigo);border:1.5px solid var(--indigo)}
.btn-outline:hover{background:var(--indigo);color:#fff}
.btn-lg{padding:1.05rem 2.3rem;font-size:1.08rem}

/* ---------- nav ---------- */
.nav{position:sticky;top:0;z-index:100;background:rgba(11,18,40,.85);
  backdrop-filter:blur(14px);-webkit-backdrop-filter:blur(14px);
  border-bottom:1px solid rgba(255,255,255,.08)}
.nav-inner{display:flex;align-items:center;gap:2rem;height:74px}
.brand{display:flex;align-items:center;gap:.7rem;color:#fff}
.brand svg{width:44px;height:44px;flex:none}
.brand-name{font-weight:800;font-size:1.14rem;letter-spacing:-.01em;line-height:1.1}
.brand-name .ai{background:linear-gradient(120deg,#C9A227,#E3C55C);
  -webkit-background-clip:text;background-clip:text;color:transparent}
.brand-sub{display:block;font-size:.62rem;font-weight:600;letter-spacing:.28em;color:var(--slate-l)}
.nav-links{display:flex;align-items:center;gap:1.7rem;margin-left:auto;list-style:none}
.nav-links a{color:#CBD5E1;font-weight:600;font-size:.95rem;transition:.2s}
.nav-links a:hover,.nav-links a.active{color:#fff}
.nav-links a.active{position:relative}
.nav-links a.active::after{content:"";position:absolute;left:0;right:0;bottom:-8px;height:2.5px;
  border-radius:2px;background:var(--grad)}
.nav-cta{margin-left:.4rem}
.nav-toggle{display:none;margin-left:auto;background:none;border:0;cursor:pointer;padding:.4rem}
.nav-toggle span{display:block;width:26px;height:2.6px;border-radius:2px;background:#fff;
  margin:5.5px 0;transition:.3s}
.nav.open .nav-toggle span:nth-child(1){transform:translateY(8px) rotate(45deg)}
.nav.open .nav-toggle span:nth-child(2){opacity:0}
.nav.open .nav-toggle span:nth-child(3){transform:translateY(-8px) rotate(-45deg)}

/* ---------- hero ---------- */
.hero{position:relative;background:var(--navy-900);color:#fff;overflow:hidden}
.hero::before,.hero::after{content:"";position:absolute;border-radius:50%;filter:blur(90px);opacity:.5}
.hero::before{width:560px;height:560px;background:#4338CA;top:-220px;left:-160px}
.hero::after{width:520px;height:520px;background:#0891B2;bottom:-260px;right:-140px}
.hero-grid{position:relative;z-index:2;display:grid;grid-template-columns:1.08fr .92fr;
  gap:clamp(2rem,5vw,4.5rem);align-items:center;padding:clamp(3.5rem,7vw,6.5rem) 0}
.hero .eyebrow{color:#A5B4FC;background:rgba(129,140,248,.12);border-color:rgba(129,140,248,.3)}
.hero p.lead{color:#B6C2D9}
.hero-ctas{display:flex;flex-wrap:wrap;gap:.9rem;margin-top:2rem}
.hero-trust{display:flex;flex-wrap:wrap;gap:1.4rem;margin-top:2.3rem;color:#9FB0CC;
  font-size:.92rem;font-weight:600}
.hero-trust span{display:inline-flex;align-items:center;gap:.45rem}
.hero-trust b{color:#fff}

/* chat mockup */
.mockup{background:rgba(255,255,255,.06);border:1px solid rgba(255,255,255,.14);
  border-radius:22px;padding:1.1rem;box-shadow:var(--shadow-lg);
  backdrop-filter:blur(8px);-webkit-backdrop-filter:blur(8px)}
.mockup-bar{display:flex;align-items:center;gap:.55rem;padding:0 .3rem .9rem}
.mockup-bar i{width:11px;height:11px;border-radius:50%;background:#334463;display:inline-block}
.mockup-bar i:nth-child(1){background:#F87171}.mockup-bar i:nth-child(2){background:#FBBF24}
.mockup-bar i:nth-child(3){background:#34D399}
.mockup-bar small{margin-left:auto;color:#8DA0C4;font-weight:600;letter-spacing:.06em}
.bubble{max-width:88%;padding:.75rem 1rem;border-radius:16px;font-size:.94rem;
  line-height:1.5;margin-bottom:.7rem}
.bubble.tutor{background:#fff;color:var(--ink);border-bottom-left-radius:4px}
.bubble.student{background:var(--grad);color:#fff;margin-left:auto;border-bottom-right-radius:4px}
.bubble .tag{display:inline-flex;align-items:center;gap:.35rem;font-size:.7rem;font-weight:800;
  letter-spacing:.1em;text-transform:uppercase;color:var(--indigo);margin-bottom:.25rem}
.bubble.reward{background:rgba(245,158,11,.14);border:1px solid rgba(245,158,11,.4);
  color:#FDE68A;font-weight:700;text-align:center;max-width:100%}

/* ---------- stats strip ---------- */
.stats{background:#fff;border-block:1px solid var(--line)}
.stats-grid{display:grid;grid-template-columns:repeat(4,1fr);text-align:center}
.stat{padding:1.9rem 1rem}
.stat+.stat{border-left:1px solid var(--line)}
.stat b{display:block;font-size:clamp(1.7rem,3vw,2.3rem);font-weight:800;
  background:var(--grad);-webkit-background-clip:text;background-clip:text;color:transparent}
.stat span{color:var(--slate);font-size:.92rem;font-weight:600}

/* ---------- cards ---------- */
.grid{display:grid;gap:1.4rem}
.grid-3{grid-template-columns:repeat(3,1fr)}
.grid-2{grid-template-columns:repeat(2,1fr)}
.card{background:var(--card);border:1px solid var(--line);border-radius:var(--radius);
  padding:1.8rem;box-shadow:var(--shadow-sm);transition:.28s}
.card:hover{transform:translateY(-5px);box-shadow:var(--shadow-md);border-color:#C7D2FE}
.card .icon{width:52px;height:52px;border-radius:14px;display:flex;align-items:center;
  justify-content:center;font-size:1.45rem;background:rgba(79,70,229,.1);margin-bottom:1.1rem}
.card h3{margin-bottom:.55rem}
.card p{color:var(--slate);font-size:.97rem}

/* problem → solution */
.ps-card{background:#fff;border:1px solid var(--line);border-radius:var(--radius);
  overflow:hidden;box-shadow:var(--shadow-sm);transition:.28s;display:flex;flex-direction:column}
.ps-card:hover{transform:translateY(-5px);box-shadow:var(--shadow-md)}
.ps-problem{padding:1.5rem 1.6rem 1.2rem}
.ps-problem .label,.ps-solution .label{display:inline-flex;align-items:center;gap:.4rem;
  font-size:.7rem;font-weight:800;letter-spacing:.12em;text-transform:uppercase;
  padding:.22rem .65rem;border-radius:999px;margin-bottom:.7rem}
.ps-problem .label{background:#FEF2F2;color:#DC2626}
.ps-solution .label{background:rgba(255,255,255,.16);color:#fff}
.ps-problem h3{font-size:1.08rem;margin-bottom:.35rem}
.ps-problem p{color:var(--slate);font-size:.93rem}
.ps-solution{margin-top:auto;background:linear-gradient(120deg,#065F46,#0D9488);color:#ECFDF5;
  padding:1.2rem 1.6rem 1.4rem;font-size:.93rem;line-height:1.55}
.ps-solution b{color:#fff}

/* steps */
.steps{counter-reset:step}
.step{position:relative;padding:1.8rem;background:#fff;border:1px solid var(--line);
  border-radius:var(--radius);box-shadow:var(--shadow-sm)}
.step::before{counter-increment:step;content:counter(step,decimal-leading-zero);
  font-size:2.6rem;font-weight:800;line-height:1;
  background:var(--grad);-webkit-background-clip:text;background-clip:text;color:transparent;
  display:block;margin-bottom:.8rem}
.step h3{margin-bottom:.5rem}
.step p{color:var(--slate);font-size:.96rem}

/* ---------- dark band / CTA ---------- */
.band{position:relative;background:var(--navy-900);color:#fff;overflow:hidden}
.band::before{content:"";position:absolute;inset:0;
  background:radial-gradient(700px 340px at 80% 10%,rgba(14,165,233,.28),transparent 65%),
             radial-gradient(600px 320px at 12% 90%,rgba(79,70,229,.3),transparent 60%)}
.band>.container{position:relative;z-index:2}
.band .lead{color:#B6C2D9}
.band .card{background:rgba(255,255,255,.05);border-color:rgba(255,255,255,.12);color:#fff}
.band .card p{color:#B6C2D9}
.band .card:hover{border-color:rgba(129,140,248,.5)}

/* ---------- courses ---------- */
.board{background:#fff;border:1px solid var(--line);border-radius:24px;
  box-shadow:var(--shadow-md);overflow:hidden;margin-bottom:2.4rem}
.board-head{display:flex;flex-wrap:wrap;align-items:center;gap:1.2rem;
  padding:1.7rem 2rem;background:var(--navy-900);color:#fff}
.board-head .icon{width:56px;height:56px;border-radius:16px;background:var(--grad);
  display:flex;align-items:center;justify-content:center;font-size:1.6rem;flex:none}
.board-head h2{font-size:1.45rem}
.board-head p{color:#9FB0CC;font-size:.92rem}
.board-badge{margin-left:auto;background:rgba(245,158,11,.16);color:#FCD34D;
  border:1px solid rgba(245,158,11,.4);font-weight:700;font-size:.8rem;
  padding:.4rem .9rem;border-radius:999px}
.board-body{display:grid;grid-template-columns:repeat(auto-fit,minmax(300px,1fr));
  gap:1.4rem;padding:1.8rem 2rem 2.1rem}
.stage{border:1px solid var(--line);border-radius:var(--radius);padding:1.5rem;transition:.25s}
.stage:hover{border-color:#A5B4FC;box-shadow:var(--shadow-md)}
.stage h3{display:flex;align-items:center;gap:.6rem;margin-bottom:1rem}
.stage h3 .dot{width:10px;height:10px;border-radius:50%;background:var(--grad);flex:none}
.subj{display:flex;gap:.8rem;align-items:flex-start;padding:.65rem 0}
.subj+.subj{border-top:1px dashed var(--line)}
.subj .em{font-size:1.3rem;line-height:1.4}
.subj b{display:block;font-size:.98rem}
.subj small{color:var(--slate);font-size:.84rem}
.extras{display:flex;flex-wrap:wrap;gap:.45rem;margin-top:1.1rem}
.extras span{font-size:.74rem;font-weight:700;color:#065F46;background:#ECFDF5;
  border:1px solid #A7F3D0;padding:.25rem .6rem;border-radius:999px}

/* ---------- pricing ---------- */
.price-card{max-width:430px;margin:0 auto;background:#fff;border-radius:26px;overflow:hidden;
  box-shadow:var(--shadow-lg);border:1px solid var(--line);text-align:center}
.price-top{background:var(--navy-900);color:#fff;padding:2.2rem 2rem 2rem;position:relative;overflow:hidden}
.price-top::before{content:"";position:absolute;inset:0;
  background:radial-gradient(400px 200px at 50% 0,rgba(14,165,233,.35),transparent 70%)}
.price-top *{position:relative}
.price-num{font-size:4rem;font-weight:800;line-height:1}
.price-num sup{font-size:1.6rem;top:-1.6rem;position:relative}
.price-num small{font-size:1.05rem;font-weight:600;color:#9FB0CC}
.price-note{color:#FCD34D;font-weight:700;margin-top:.4rem;font-size:.95rem}
.price-list{list-style:none;padding:1.8rem 2.2rem;text-align:left}
.price-list li{display:flex;gap:.7rem;padding:.5rem 0;color:var(--slate);font-size:.97rem}
.price-list li::before{content:"✓";flex:none;width:22px;height:22px;border-radius:50%;
  background:#ECFDF5;color:#059669;font-weight:800;display:flex;align-items:center;
  justify-content:center;font-size:.8rem;margin-top:.15rem}
.price-cta{padding:0 2.2rem 2.2rem}

.compare{width:100%;border-collapse:separate;border-spacing:0;background:#fff;
  border:1px solid var(--line);border-radius:var(--radius);overflow:hidden;box-shadow:var(--shadow-sm)}
.compare th,.compare td{padding:.95rem 1.1rem;text-align:center;font-size:.94rem;
  border-bottom:1px solid var(--line)}
.compare th{background:var(--navy-900);color:#fff;font-size:.9rem}
.compare th:first-child,.compare td:first-child{text-align:left;font-weight:600}
.compare td{color:var(--slate)}
.compare tr:last-child td{border-bottom:0}
.compare .win{background:rgba(6,182,212,.07);color:var(--ink);font-weight:700}
.compare th.win{background:linear-gradient(120deg,#4F46E5,#0891B2);color:#fff}
.table-wrap{overflow-x:auto;border-radius:var(--radius)}

/* ---------- FAQ ---------- */
.faq{max-width:760px;margin:0 auto}
.faq details{background:#fff;border:1px solid var(--line);border-radius:14px;
  margin-bottom:.8rem;overflow:hidden}
.faq summary{cursor:pointer;list-style:none;display:flex;justify-content:space-between;
  align-items:center;gap:1rem;padding:1.1rem 1.4rem;font-weight:700}
.faq summary::-webkit-details-marker{display:none}
.faq summary::after{content:"+";font-size:1.5rem;font-weight:600;color:var(--indigo);
  transition:.25s;line-height:1}
.faq details[open] summary::after{transform:rotate(45deg)}
.faq details p{padding:0 1.4rem 1.2rem;color:var(--slate);font-size:.96rem}

/* ---------- offices / contact ---------- */
.office{display:flex;gap:1.1rem;align-items:flex-start}
.office .icon{flex:none}
.office h3{margin-bottom:.3rem}
.office p{color:var(--slate);font-size:.95rem}

.form-card{background:#fff;border:1px solid var(--line);border-radius:22px;
  padding:2.2rem;box-shadow:var(--shadow-md)}
.form-grid{display:grid;grid-template-columns:1fr 1fr;gap:1.1rem}
.field{display:flex;flex-direction:column;gap:.35rem}
.field.full{grid-column:1/-1}
.field label{font-weight:700;font-size:.88rem}
.field input,.field select,.field textarea{font-family:var(--font);font-size:.97rem;
  padding:.75rem .95rem;border:1.5px solid var(--line);border-radius:12px;background:#F8FAFC;
  transition:.2s;color:var(--ink)}
.field input:focus,.field select:focus,.field textarea:focus{outline:none;
  border-color:var(--indigo);background:#fff;box-shadow:0 0 0 4px rgba(79,70,229,.12)}
.field textarea{resize:vertical;min-height:130px}
.alert{padding:1rem 1.3rem;border-radius:14px;font-weight:600;margin-bottom:1.4rem}
.alert.ok{background:#ECFDF5;color:#065F46;border:1px solid #A7F3D0}
.alert.err{background:#FEF2F2;color:#991B1B;border:1px solid #FECACA}
.hp{position:absolute;left:-6000px;opacity:0;height:0;overflow:hidden}

/* ---------- footer ---------- */
.footer{background:var(--navy-900);color:#9FB0CC;padding:3.5rem 0 0;font-size:.94rem}
.footer-grid{display:grid;grid-template-columns:1.4fr 1fr 1fr 1.2fr;gap:2.5rem;padding-bottom:2.5rem}
.footer h4{color:#fff;font-size:.95rem;margin-bottom:1rem;letter-spacing:.04em}
.footer ul{list-style:none}
.footer li{margin-bottom:.55rem}
.footer a{color:#9FB0CC;transition:.2s}
.footer a:hover{color:#fff}
.footer .brand{margin-bottom:1rem}
.footer-bottom{border-top:1px solid rgba(255,255,255,.09);padding:1.3rem 0;
  display:flex;flex-wrap:wrap;gap:.8rem;justify-content:space-between;font-size:.85rem}

/* ---------- reveal animation ---------- */
.reveal{opacity:0;transform:translateY(26px);transition:opacity .7s ease,transform .7s ease}
.reveal.in{opacity:1;transform:none}
@media (prefers-reduced-motion:reduce){
  .reveal{opacity:1;transform:none;transition:none}
  html{scroll-behavior:auto}
}

/* ---------- responsive ---------- */
@media (max-width:980px){
  .hero-grid{grid-template-columns:1fr}
  .mockup{max-width:540px}
  .grid-3{grid-template-columns:repeat(2,1fr)}
  .footer-grid{grid-template-columns:1fr 1fr}
}
@media (max-width:860px){
  .nav-toggle{display:block}
  .nav-links{position:absolute;top:74px;left:0;right:0;flex-direction:column;
    align-items:flex-start;gap:0;background:var(--navy-900);
    border-bottom:1px solid rgba(255,255,255,.1);max-height:0;overflow:hidden;transition:.35s}
  .nav.open .nav-links{max-height:440px}
  .nav-links li{width:100%}
  .nav-links a{display:block;padding:1rem 5%}
  .nav-links a.active::after{display:none}
  .nav-cta{margin:.6rem 5% 1.2rem}
  .stats-grid{grid-template-columns:repeat(2,1fr)}
  .stat:nth-child(3){border-left:0}
  .stat:nth-child(n+3){border-top:1px solid var(--line)}
}
@media (max-width:640px){
  .grid-3,.grid-2,.form-grid{grid-template-columns:1fr}
  .footer-grid{grid-template-columns:1fr}
  .board-head{padding:1.4rem}
  .board-body{padding:1.3rem;grid-template-columns:1fr}
  .board-badge{margin-left:0}
  .form-card{padding:1.5rem}
}