/* ===== RESET & BASE ===== */
*,*::before,*::after{box-sizing:border-box;margin:0;padding:0}
html{scroll-behavior:smooth;-webkit-text-size-adjust:100%}

:root{
  --bg-0:#f5f7fb;
  --bg-1:#ffffff;
  --bg-2:#eef2f7;
  --bg-dark:#0c1222;
  --bg-dark-2:#141c30;
  --ink:#0f172a;
  --muted:#5b6474;
  --soft:#7a8699;
  --accent-1:#10b981;
  --accent-2:#6366f1;
  --accent-3:#818cf8;
  --glass:rgba(255,255,255,0.86);
  --border:rgba(148,163,184,0.35);
  --shadow-1:0 16px 40px rgba(15,23,42,0.06);
  --shadow-2:0 30px 80px rgba(15,23,42,0.08);
  --radius:12px;
  --radius-lg:20px;
  --max-w:1120px;
  --font-body:'Nunito Sans',system-ui,-apple-system,sans-serif;
  --font-heading:'Source Serif 4',Georgia,serif;
}

body{
  font-family:var(--font-body);
  font-size:16px;
  line-height:1.65;
  color:var(--ink);
  background:var(--bg-0);
  -webkit-font-smoothing:antialiased;
}

a{color:inherit;text-decoration:none}
img{max-width:100%;display:block}
ul{list-style:none}

.page{min-height:100vh;display:flex;flex-direction:column}
.container{max-width:var(--max-w);margin:0 auto;padding:0 24px}

/* ===== ANIMATIONS ===== */
@keyframes fadeUp{
  from{opacity:0;transform:translateY(24px)}
  to{opacity:1;transform:translateY(0)}
}
.fade-up{animation:fadeUp .5s ease both}
@media(prefers-reduced-motion:reduce){.fade-up{animation:none}}

/* ===== NAV ===== */
.nav{
  position:sticky;top:0;z-index:100;
  background:var(--glass);
  backdrop-filter:blur(16px);-webkit-backdrop-filter:blur(16px);
  border-bottom:1px solid var(--border);
}
.nav-inner{
  max-width:var(--max-w);margin:0 auto;padding:0 24px;
  height:64px;display:flex;align-items:center;gap:32px;
}
.logo{display:flex;align-items:center;gap:10px;font-weight:700;font-size:18px;letter-spacing:-.02em}
.logo-mark{flex-shrink:0}
.nav-links{display:flex;gap:28px;margin-left:auto}
.nav-links a{
  font-size:14px;font-weight:600;color:var(--muted);
  position:relative;transition:color .18s;
}
.nav-links a:hover{color:var(--ink)}
.nav-links a::after{
  content:'';position:absolute;left:0;bottom:-4px;
  width:0;height:2px;background:var(--accent-1);
  transition:width .18s;
}
.nav-links a:hover::after{width:100%}

/* ===== BUTTONS ===== */
.btn{
  display:inline-flex;align-items:center;justify-content:center;
  padding:10px 22px;border-radius:8px;font-size:14px;font-weight:700;
  background:linear-gradient(135deg,var(--accent-1),var(--accent-2));
  color:#fff;border:none;cursor:pointer;
  transition:transform .18s,box-shadow .18s;
  text-decoration:none;
}
.btn:hover{transform:translateY(-1px);box-shadow:0 8px 24px rgba(16,185,129,0.25)}
.btn-lg{padding:14px 32px;font-size:16px;border-radius:10px}
.btn-sm{padding:8px 18px;font-size:13px}
.btn-ghost{
  background:transparent;color:var(--ink);
  border:1.5px solid var(--border);
}
.btn-ghost:hover{border-color:var(--accent-1);color:var(--accent-1);box-shadow:none;transform:translateY(-1px)}

/* ===== PILL & TAG ===== */
.pill{
  display:inline-block;padding:6px 16px;border-radius:100px;
  font-size:13px;font-weight:700;letter-spacing:.02em;
  background:linear-gradient(135deg,rgba(16,185,129,.1),rgba(99,102,241,.1));
  color:var(--accent-2);
}
.tag{
  display:inline-block;padding:4px 12px;border-radius:6px;
  font-size:12px;font-weight:600;color:var(--soft);
  background:var(--bg-2);
}

/* ===== HERO ===== */
.hero{
  padding:80px 24px 64px;
  max-width:var(--max-w);margin:0 auto;
}
.hero-grid{
  display:grid;grid-template-columns:1fr 1fr;gap:56px;align-items:center;
}
.hero-copy h1{
  font-family:var(--font-heading);font-size:clamp(32px,4.5vw,52px);
  line-height:1.15;font-weight:700;letter-spacing:-.025em;
  margin:16px 0 20px;
}
.hero-sub{
  font-size:18px;line-height:1.6;color:var(--muted);max-width:520px;margin-bottom:28px;
}
.hero-actions{display:flex;gap:12px;flex-wrap:wrap;margin-bottom:24px}
.hero-meta{display:flex;gap:8px;flex-wrap:wrap}

/* Editor preview */
.editor-frame{
  background:var(--bg-1);border-radius:var(--radius-lg);
  border:1px solid var(--border);
  box-shadow:var(--shadow-2);overflow:hidden;
}
.editor-toolbar{
  display:flex;align-items:center;gap:10px;
  padding:12px 20px;
  background:var(--bg-2);
  border-bottom:1px solid var(--border);
  font-size:12px;font-weight:600;color:var(--soft);
}
.editor-dot{width:10px;height:10px;border-radius:50%}
.editor-dot-r{background:#f38ba8}
.editor-dot-y{background:#f9e2af}
.editor-dot-g{background:#a6e3a1}
.editor-title{flex:1;text-align:center;color:var(--muted)}
.editor-status{font-size:11px;color:var(--accent-1)}
.editor-body{padding:24px;font-size:14px;line-height:1.8;color:var(--ink)}
.editor-body p{margin-bottom:12px}
.editor-cursor{
  display:inline-block;width:2px;height:16px;
  background:var(--accent-1);
  animation:blink 1s step-end infinite;
  vertical-align:text-bottom;margin-left:1px;
}
@keyframes blink{50%{opacity:0}}
.editor-meta{
  padding:12px 20px;border-top:1px solid var(--border);
  display:flex;justify-content:space-between;
  font-size:11px;color:var(--soft);
}

/* ===== SECTIONS ===== */
.section{padding:80px 0}
.section-alt{background:var(--bg-2)}
.section-dark{
  background:var(--bg-dark);color:#fff;
}
.section-dark .section-header p{color:rgba(255,255,255,.6)}
.section-dark .stat-label{color:rgba(255,255,255,.5)}
.section-header{text-align:center;max-width:640px;margin:0 auto 48px}
.section-header h2{
  font-family:var(--font-heading);font-size:clamp(26px,3.2vw,40px);
  font-weight:700;letter-spacing:-.02em;line-height:1.2;margin-bottom:12px;
}
.section-header p{color:var(--muted);font-size:17px}

/* ===== STATS ===== */
.stats-grid{display:grid;grid-template-columns:repeat(3,1fr);gap:24px}
.stat-card{
  text-align:center;padding:36px 24px;border-radius:var(--radius);
  background:var(--bg-dark-2);
}
.stat-num{
  display:block;font-family:var(--font-heading);font-size:clamp(36px,4vw,48px);
  font-weight:700;
  background:linear-gradient(135deg,var(--accent-1),var(--accent-3));
  -webkit-background-clip:text;-webkit-text-fill-color:transparent;
  background-clip:text;
  margin-bottom:8px;
}
.stat-label{font-size:14px;line-height:1.5}

/* ===== FEATURES ===== */
.feature-category{margin-bottom:48px}
.feature-category:last-child{margin-bottom:0}
.feature-category-title{
  font-family:var(--font-heading);font-size:20px;font-weight:700;
  letter-spacing:-.01em;margin-bottom:20px;
  padding-bottom:12px;border-bottom:2px solid var(--border);
  color:var(--ink);
}
.feature-grid{display:grid;grid-template-columns:repeat(3,1fr);gap:24px}
.feature{
  padding:32px;border-radius:var(--radius);
  background:var(--bg-1);border:1px solid var(--border);
  transition:transform .2s,box-shadow .2s;
}
.feature:hover{transform:translateY(-4px);box-shadow:var(--shadow-1)}
.feature-highlight{
  border:2px solid var(--accent-1);
  background:linear-gradient(135deg,rgba(16,185,129,.03),rgba(99,102,241,.03));
}
.feature-icon{
  width:48px;height:48px;border-radius:10px;
  display:flex;align-items:center;justify-content:center;
  background:linear-gradient(135deg,rgba(16,185,129,.1),rgba(99,102,241,.1));
  color:var(--accent-2);margin-bottom:16px;
}
.feature-icon-purple{
  background:linear-gradient(135deg,rgba(99,102,241,.1),rgba(129,140,248,.1));
  color:var(--accent-2);
}
.feature-icon-gradient{
  background:linear-gradient(135deg,var(--accent-1),var(--accent-2));
  color:#fff;
}
.feature h3{font-size:17px;font-weight:700;margin-bottom:8px}
.feature p{font-size:14px;color:var(--muted);line-height:1.6}

/* ===== BENEFITS ===== */
.benefits-grid{display:grid;grid-template-columns:1fr 1fr;gap:32px}
.benefit-card{
  padding:40px 36px;border-radius:var(--radius-lg);
  background:var(--bg-dark-2);
  border:1px solid rgba(255,255,255,.08);
}
.benefit-card-teacher{border-top:3px solid var(--accent-1)}
.benefit-card-student{border-top:3px solid var(--accent-3)}
.benefit-badge{
  display:inline-block;padding:4px 14px;border-radius:100px;
  font-size:12px;font-weight:700;letter-spacing:.03em;
  background:rgba(16,185,129,.15);color:var(--accent-1);
  margin-bottom:16px;
}
.benefit-badge-alt{
  background:rgba(129,140,248,.15);color:var(--accent-3);
}
.benefit-card h3{
  font-family:var(--font-heading);font-size:22px;font-weight:700;
  line-height:1.3;margin-bottom:20px;color:#fff;
}
.benefit-list{list-style:none;display:flex;flex-direction:column;gap:12px}
.benefit-list li{
  font-size:14px;line-height:1.6;color:rgba(255,255,255,.6);
  padding-left:24px;position:relative;
}
.benefit-card-teacher .benefit-list li::before{
  content:'\2713';position:absolute;left:0;color:var(--accent-1);font-weight:700;
}
.benefit-card-student .benefit-list li::before{
  content:'\2713';position:absolute;left:0;color:var(--accent-3);font-weight:700;
}

/* ===== STEPS ===== */
.steps-grid{display:grid;grid-template-columns:repeat(3,1fr);gap:32px;counter-reset:step}
.steps-grid-4{grid-template-columns:repeat(4,1fr)}
.step{
  text-align:center;padding:40px 28px;
  border-radius:var(--radius);background:var(--bg-1);
  border:1px solid var(--border);
}
.step-num{
  width:48px;height:48px;border-radius:50%;margin:0 auto 20px;
  display:flex;align-items:center;justify-content:center;
  font-family:var(--font-heading);font-size:20px;font-weight:700;color:#fff;
  background:linear-gradient(135deg,var(--accent-1),var(--accent-2));
}
.step h3{font-size:17px;font-weight:700;margin-bottom:8px}
.step p{font-size:14px;color:var(--muted);line-height:1.6}

/* ===== COMPARISON ===== */
.compare-grid{display:grid;grid-template-columns:1fr 1fr;gap:32px}
.compare-card{
  padding:36px 32px;border-radius:var(--radius-lg);
  background:var(--bg-1);border:1px solid var(--border);
}
.compare-card-accent{
  border:2px solid var(--accent-1);
  box-shadow:var(--shadow-1);
}
.compare-card h3{font-size:18px;font-weight:700;margin-bottom:16px}
.compare-list li{
  padding:10px 0;font-size:14px;color:var(--muted);
  border-bottom:1px solid var(--border);
  padding-left:24px;position:relative;
}
.compare-list-yes li::before{content:'\2713';position:absolute;left:0;color:var(--accent-1);font-weight:700}
.compare-list-no li::before{content:'\2717';position:absolute;left:0;color:#f38ba8;font-weight:700}

/* ===== FAQ ===== */
.faq-grid{display:grid;grid-template-columns:repeat(2,1fr);gap:24px}
.faq-item{
  padding:28px;border-radius:var(--radius);
  background:var(--bg-1);border:1px solid var(--border);
}
.faq-item h3{font-size:16px;font-weight:700;margin-bottom:8px}
.faq-item p{font-size:14px;color:var(--muted);line-height:1.6}

/* ===== CTA ===== */
.section-cta{
  padding:80px 24px;text-align:center;
  background:linear-gradient(135deg,var(--bg-dark),var(--bg-dark-2));
  color:#fff;
}
.section-cta h2{
  font-family:var(--font-heading);font-size:clamp(28px,3.5vw,44px);
  font-weight:700;letter-spacing:-.02em;margin-bottom:12px;
}
.section-cta p{color:rgba(255,255,255,.6);font-size:17px;margin-bottom:32px}
.cta-form{max-width:480px;margin:0 auto 20px}
.cta-note{font-size:14px;color:rgba(255,255,255,.4)}
.cta-note strong{color:rgba(255,255,255,.7)}

/* ===== FOOTER ===== */
.footer{
  background:var(--bg-dark);color:rgba(255,255,255,.5);
  padding:56px 0 0;margin-top:auto;
}
.footer-inner{
  max-width:var(--max-w);margin:0 auto;padding:0 24px;
  display:flex;gap:48px;justify-content:space-between;
}
.footer-brand{max-width:280px}
.footer-brand .logo{margin-bottom:12px}
.footer-brand .logo-text{color:#fff}
.footer-tagline{font-size:14px;line-height:1.6}
.footer-links{display:flex;gap:56px}
.footer-col{display:flex;flex-direction:column;gap:8px}
.footer-col h4{color:#fff;font-size:13px;font-weight:700;text-transform:uppercase;letter-spacing:.06em;margin-bottom:4px}
.footer-col a{font-size:14px;transition:color .18s}
.footer-col a:hover{color:var(--accent-1)}
.footer-bottom{
  max-width:var(--max-w);margin:0 auto;padding:32px 24px;
  margin-top:40px;border-top:1px solid rgba(255,255,255,.08);
  font-size:13px;
}

/* ===== DARK MODE COMPARE ===== */
.dark-mode-compare{display:grid;grid-template-columns:1fr 1fr;gap:24px;max-width:800px;margin:0 auto}

/* ===== RESPONSIVE ===== */
@media(max-width:960px){
  .nav-links{display:none}
  .hero-grid{grid-template-columns:1fr;gap:40px}
  .hero-copy{text-align:center}
  .hero-sub{margin-left:auto;margin-right:auto}
  .hero-actions{justify-content:center}
  .hero-meta{justify-content:center}
  .compare-grid{grid-template-columns:1fr}
  .benefits-grid{grid-template-columns:1fr}
  .steps-grid-4{grid-template-columns:repeat(2,1fr)}
}

@media(max-width:720px){
  .hero{padding:48px 24px 40px}
  .section{padding:56px 0}
  .stats-grid,
  .feature-grid,
  .steps-grid,
  .steps-grid-4,
  .faq-grid{grid-template-columns:1fr}
  .footer-inner{flex-direction:column;gap:32px}
  .footer-links{flex-direction:column;gap:24px}
  .section-cta{padding:56px 24px}
  .dark-mode-compare{grid-template-columns:1fr}
}