@import url('https://fonts.googleapis.com/css2?family=Inter:wght@400;500;600;700;800;900&display=swap');
*,*::before,*::after{margin:0;padding:0;box-sizing:border-box}
:root{--bg:#f7f4ff;--card:#fff;--purple:#7c3aed;--purple2:#a855f7;--dark:#12082a;--text:#1e1040;--muted:#6b7280;--border:#e5e0f5}
html{scroll-behavior:smooth}
body{background:var(--bg);color:var(--text);font-family:'Inter',sans-serif;overflow-x:hidden}

/* ── GLOBAL BG CANVAS ── */
#bgCanvas{position:fixed;top:0;left:0;width:100%;height:100%;pointer-events:none;z-index:0;opacity:.5}

/* ── NAV ── */
.nav{display:flex;align-items:center;justify-content:space-between;padding:16px 60px;background:rgba(247,244,255,.88);backdrop-filter:blur(16px);position:sticky;top:0;z-index:100;border-bottom:1px solid var(--border)}
.nav-logo{display:flex;align-items:center;gap:10px;font-size:18px;font-weight:700;color:var(--dark);text-decoration:none}
.nav-logo-icon{width:36px;height:36px;border-radius:10px;background:linear-gradient(135deg,var(--purple),var(--purple2));display:flex;align-items:center;justify-content:center;flex-shrink:0}
.nav-logo-icon.small{width:28px;height:28px;border-radius:8px}
.nav-links{display:flex;gap:32px;list-style:none}
.nav-links a{color:var(--muted);text-decoration:none;font-size:15px;font-weight:500;transition:color .2s}
.nav-links a:hover{color:var(--purple)}
.nav-right{display:flex;align-items:center;gap:12px}
.openai-badge{display:inline-flex;align-items:center;gap:6px;padding:7px 14px;border-radius:100px;border:1.5px solid rgba(124,58,237,.25);background:rgba(124,58,237,.07);color:var(--purple);font-size:12px;font-weight:700;text-decoration:none;transition:all .2s}
.openai-badge:hover{background:rgba(124,58,237,.14);border-color:var(--purple)}
.nav-cta{background:var(--dark);color:#fff;padding:10px 22px;border-radius:100px;font-size:14px;font-weight:700;text-decoration:none;transition:all .2s}
.nav-cta:hover{background:var(--purple);transform:translateY(-1px)}

/* ── HERO ── */
.hero{display:grid;grid-template-columns:1fr 1fr;gap:40px;align-items:center;padding:90px 60px 70px;min-height:92vh;position:relative;z-index:1}

.hero-badge{display:inline-flex;align-items:center;gap:7px;padding:7px 18px;border-radius:100px;background:rgba(124,58,237,.1);border:1px solid rgba(124,58,237,.25);font-size:11px;font-weight:800;letter-spacing:2px;color:var(--purple);margin-bottom:28px}
.hero-title{font-size:64px;font-weight:900;line-height:1.03;letter-spacing:-2.5px;color:var(--dark);margin-bottom:22px}
.hero-accent{color:var(--purple)}
.cursor{animation:blink .8s step-end infinite;color:var(--purple)}
@keyframes blink{50%{opacity:0}}
.hero-sub{font-size:17px;color:var(--muted);line-height:1.75;margin-bottom:38px}

.hero-input-wrap{display:flex;align-items:center;gap:10px;background:#fff;border:1.5px solid var(--border);border-radius:100px;padding:8px 8px 8px 20px;box-shadow:0 4px 28px rgba(124,58,237,.1);max-width:520px;transition:border-color .2s,box-shadow .2s}
.hero-input-wrap:focus-within{border-color:var(--purple);box-shadow:0 4px 28px rgba(124,58,237,.2)}
.input-icon{flex-shrink:0;opacity:.5}
.hero-input-wrap input{flex:1;border:none;outline:none;font-family:inherit;font-size:15px;color:var(--dark);background:transparent;min-width:0}
.hero-input-wrap input::placeholder{color:#b0a8c8}
.hero-send-btn{width:46px;height:46px;border-radius:50%;background:linear-gradient(135deg,var(--purple),var(--purple2));border:none;color:#fff;cursor:pointer;display:flex;align-items:center;justify-content:center;flex-shrink:0;transition:transform .2s,box-shadow .2s;box-shadow:0 4px 14px rgba(124,58,237,.35)}
.hero-send-btn:hover{transform:scale(1.08);box-shadow:0 8px 22px rgba(124,58,237,.45)}
.hero-send-btn:disabled{opacity:.5;cursor:not-allowed;transform:none}

.explain-toggle{display:flex;align-items:center;gap:8px;margin-top:14px;flex-wrap:wrap}
.format-picker{display:flex;align-items:center;gap:8px;margin-top:10px;flex-wrap:wrap}
.format-label{font-size:12px;font-weight:700;color:var(--muted);letter-spacing:.5px}
.fmt-btn{display:inline-flex;align-items:center;gap:5px;padding:6px 13px;border-radius:100px;border:1.5px solid var(--border);background:#fff;color:var(--muted);font-family:inherit;font-size:12px;font-weight:600;cursor:pointer;transition:all .18s}
.fmt-btn:hover{border-color:var(--purple);color:var(--purple)}
.fmt-btn.active{background:var(--purple);color:#fff;border-color:var(--purple);box-shadow:0 2px 10px rgba(124,58,237,.3)}
.hero-badges{display:flex;gap:22px;margin-top:22px}
.hero-badges span{display:flex;align-items:center;gap:6px;font-size:13px;font-weight:600;color:var(--muted)}

.hero-right{display:flex;justify-content:center;align-items:center;position:relative;z-index:1}
.hero-circle-wrap{position:relative;width:520px;height:520px}
.hero-circle-wrap canvas{border-radius:50%;display:block;box-shadow:0 0 80px rgba(124,58,237,.2)}
.hero-steps{position:absolute;right:-24px;top:50%;transform:translateY(-50%);display:flex;flex-direction:column;gap:10px}
.step-pill{background:#fff;border:1px solid var(--border);border-radius:14px;padding:11px 16px;font-size:12px;font-weight:700;color:var(--muted);box-shadow:0 2px 12px rgba(0,0,0,.06);white-space:nowrap;display:flex;align-items:center;gap:7px;transition:all .3s}
.step-pill.active{background:var(--purple);color:#fff;border-color:var(--purple);box-shadow:0 4px 16px rgba(124,58,237,.35);transform:scale(1.05)}

/* ── RESULT ── */
.result-section{max-width:820px;margin:40px auto;background:#fff;border-radius:24px;box-shadow:0 12px 48px rgba(124,58,237,.15);overflow:hidden;border:1px solid var(--border);position:relative;z-index:2}
.result-inner{padding:32px}
.result-title{font-size:20px;font-weight:800;color:var(--dark);margin-bottom:20px;display:flex;align-items:center;gap:10px}
.result-video-wrap{background:#000;border-radius:16px;overflow:hidden;margin-bottom:20px}
.result-video-wrap video{width:100%;max-height:420px;display:block}
.result-row{display:flex;gap:12px;flex-wrap:wrap}
.summary-block{margin-top:20px;background:linear-gradient(135deg,rgba(124,58,237,.06),rgba(168,85,247,.04));border:1.5px solid rgba(124,58,237,.18);border-radius:16px;padding:20px 24px}
.summary-title{display:flex;align-items:center;gap:8px;font-size:13px;font-weight:800;color:var(--purple);letter-spacing:.5px;margin-bottom:12px;text-transform:uppercase}
.summary-content{font-size:15px;color:var(--text);line-height:1.8}
.summary-content .katex-display{margin:.6em 0}
.code-block{margin-top:20px;background:#f8f5ff;border-radius:12px;padding:20px;overflow-x:auto}
pre{font-size:12px;color:#4a3f6b;line-height:1.6;font-family:'Courier New',monospace;white-space:pre-wrap}

/* ── BUTTONS ── */
.btn-primary{display:inline-flex;align-items:center;gap:8px;padding:12px 28px;border-radius:100px;background:linear-gradient(135deg,var(--purple),var(--purple2));color:#fff;font-family:inherit;font-size:15px;font-weight:700;text-decoration:none;border:none;cursor:pointer;transition:all .2s;box-shadow:0 4px 16px rgba(124,58,237,.3)}
.btn-primary:hover{transform:translateY(-2px);box-shadow:0 10px 28px rgba(124,58,237,.4)}
.btn-primary.large{padding:18px 44px;font-size:17px}
.btn-secondary{display:inline-flex;align-items:center;gap:8px;padding:12px 20px;border-radius:100px;background:transparent;border:1.5px solid var(--border);color:var(--muted);font-family:inherit;font-size:14px;font-weight:600;cursor:pointer;transition:all .2s}
.btn-secondary:hover{border-color:var(--purple);color:var(--purple)}
.error-box{max-width:820px;margin:16px auto;padding:14px 20px;background:rgba(239,68,68,.08);border:1px solid rgba(239,68,68,.25);border-radius:12px;color:#dc2626;font-size:14px;position:relative;z-index:2}

/* ── PROCESS BAR ── */
.process-bar{display:grid;grid-template-columns:repeat(4,1fr);background:var(--dark);position:relative;z-index:1;overflow:hidden}
.process-bar::before{content:'';position:absolute;inset:0;background:radial-gradient(ellipse 80% 100% at 50% 0%,rgba(124,58,237,.15),transparent);pointer-events:none}
.process-item{padding:32px 28px;display:flex;align-items:flex-start;gap:16px;border-right:1px solid rgba(255,255,255,.05);transition:background .3s}
.process-item:hover{background:rgba(255,255,255,.03)}
.process-item:last-child{border-right:none}
.proc-icon{width:48px;height:48px;border-radius:14px;display:flex;align-items:center;justify-content:center;flex-shrink:0}
.proc-title{font-size:15px;font-weight:700;color:#fff;margin-bottom:6px}
.proc-desc{font-size:13px;color:rgba(255,255,255,.4);line-height:1.55}

/* ── EXAMPLES ── */
.examples-section{padding:90px 60px;position:relative;z-index:1}
.section-head{margin-bottom:40px}
.section-tag{font-size:11px;font-weight:800;letter-spacing:3px;color:var(--purple);margin-bottom:10px}
.section-head h2{font-size:38px;font-weight:900;color:var(--dark);letter-spacing:-1.2px}
.examples-grid{display:grid;grid-template-columns:repeat(5,1fr);gap:18px}
.ex-card{background:#fff;border:1px solid var(--border);border-radius:20px;overflow:hidden;cursor:pointer;transition:all .25s;position:relative;box-shadow:0 2px 12px rgba(0,0,0,.04)}
.ex-card:hover{transform:translateY(-6px);box-shadow:0 16px 40px rgba(124,58,237,.14);border-color:rgba(124,58,237,.25)}
.ex-canvas{width:100%;display:block}
.ex-num{position:absolute;top:10px;left:10px;font-size:10px;font-weight:800;color:rgba(255,255,255,.75);background:rgba(0,0,0,.35);border-radius:6px;padding:3px 8px;letter-spacing:1px}
.ex-play{position:absolute;top:10px;right:10px;display:flex;align-items:center;gap:5px;font-size:10px;font-weight:700;color:#fff;background:rgba(124,58,237,.7);border-radius:8px;padding:4px 10px;opacity:0;transform:translateY(-4px);transition:all .2s}
.ex-card:hover .ex-play{opacity:1;transform:translateY(0)}
.ex-info{padding:13px 14px 16px}
.ex-name{font-size:13px;font-weight:700;color:var(--dark);margin-bottom:4px}
.ex-desc{font-size:11px;color:var(--muted);line-height:1.5}

/* ── STATS ── */
.stats-section{margin:0 60px 90px;background:var(--dark);border-radius:28px;padding:60px;display:grid;grid-template-columns:1fr 1fr;gap:48px;align-items:center;position:relative;overflow:hidden;z-index:1}
.stats-section::before{content:'';position:absolute;top:-100px;left:-100px;width:400px;height:400px;background:radial-gradient(circle,rgba(124,58,237,.2),transparent 70%);pointer-events:none}
.stats-left{display:flex;flex-direction:column;gap:36px;position:relative;z-index:1}
.stat{display:flex;flex-direction:column;gap:5px}
.stat-num{font-size:56px;font-weight:900;color:var(--purple2);letter-spacing:-2px;line-height:1}
.stat-label{font-size:15px;color:rgba(255,255,255,.45);font-weight:500}
.stats-right{position:relative;z-index:1}
.stats-right canvas{border-radius:20px;width:100%;display:block}

/* ── CTA ── */
.cta-section{text-align:center;padding:90px 60px;background:linear-gradient(135deg,rgba(124,58,237,.05),rgba(168,85,247,.05));position:relative;z-index:1;overflow:hidden}
.cta-section::before{content:'';position:absolute;top:50%;left:50%;transform:translate(-50%,-50%);width:600px;height:300px;background:radial-gradient(ellipse,rgba(124,58,237,.1),transparent 70%);pointer-events:none}
.cta-inner{position:relative;z-index:1}
.cta-section h2{font-size:48px;font-weight:900;color:var(--dark);letter-spacing:-1.5px;margin-bottom:14px}
.cta-section p{font-size:18px;color:var(--muted);margin-bottom:38px}

/* ── FOOTER ── */
.footer{background:var(--dark);padding:60px 60px 36px;display:grid;grid-template-columns:1fr 1fr;gap:40px;position:relative;z-index:1}
.footer-brand{color:rgba(255,255,255,.45);font-size:14px;line-height:1.7}
.footer-logo{display:flex;align-items:center;gap:10px;font-size:17px;font-weight:700;color:#fff;margin-bottom:14px}
.footer-links{display:flex;gap:48px}
.footer-links div{display:flex;flex-direction:column;gap:10px}
.footer-links strong{color:#fff;font-size:14px;margin-bottom:4px;display:block}
.footer-links a{color:rgba(255,255,255,.4);font-size:14px;text-decoration:none;transition:color .2s}
.footer-links a:hover{color:#fff}
.footer-copy{grid-column:1/-1;border-top:1px solid rgba(255,255,255,.06);padding-top:24px;font-size:13px;color:rgba(255,255,255,.25);text-align:center}

/* ── REVEAL ANIMATIONS ── */
.reveal,.reveal-up{opacity:0;transform:translateY(30px);transition:opacity .7s ease,transform .7s ease}
.reveal.visible,.reveal-up.visible{opacity:1;transform:translateY(0)}

/* ── MISC ── */
.spinner{width:20px;height:20px;border:2.5px solid rgba(255,255,255,.3);border-top-color:#fff;border-radius:50%;animation:spin .7s linear infinite}
@keyframes spin{to{transform:rotate(360deg)}}
.hidden{display:none!important}

@media(max-width:1100px){
  .hero{grid-template-columns:1fr;padding:60px 30px;min-height:auto}
  .hero-right{display:none}
  .hero-title{font-size:44px}
  .examples-grid{grid-template-columns:repeat(2,1fr)}
  .process-bar{grid-template-columns:repeat(2,1fr)}
  .stats-section{grid-template-columns:1fr;margin:0 20px 60px}
  .footer{grid-template-columns:1fr}
  .nav{padding:14px 24px}
  .examples-section,.cta-section{padding:60px 24px}
}