*,*::before,*::after{margin:0;padding:0;box-sizing:border-box}
:root{
  --bg-1:#06080f;--bg-2:#0d1117;--bg-card:rgba(255,255,255,0.035);--bg-card-h:rgba(255,255,255,0.07);
  --tx-1:#eef2ff;--tx-2:#8892a8;
  --ac-1:#818cf8;--ac-2:#c084fc;--ac-3:#38bdf8;--ac-4:#f472b6;
  --grad:linear-gradient(135deg,#818cf8,#c084fc,#f472b6);
  --grad2:linear-gradient(135deg,#38bdf8,#818cf8,#c084fc);
  --grad-s:linear-gradient(135deg,rgba(129,140,248,.12),rgba(192,132,252,.12));
  --brd:rgba(255,255,255,0.06);--brd-h:rgba(129,140,248,.3);
  --radius:20px;--radius-sm:12px;
  --glow:0 0 60px rgba(129,140,248,.15);
  --shadow:0 20px 60px rgba(0,0,0,.4);
  --font:'Inter',system-ui,sans-serif;--font-d:'Outfit',system-ui,sans-serif;
}
[data-theme="light"]{
  --bg-1:#f0f2f8;--bg-2:#ffffff;--bg-card:rgba(0,0,0,.025);--bg-card-h:rgba(0,0,0,.05);
  --tx-1:#0f172a;--tx-2:#475569;--brd:rgba(0,0,0,.07);--brd-h:rgba(99,102,241,.25);
  --shadow:0 20px 60px rgba(0,0,0,.06);--glow:0 0 60px rgba(99,102,241,.08);
  --grad-s:linear-gradient(135deg,rgba(99,102,241,.06),rgba(168,85,247,.06));
}
html{scroll-behavior:smooth}
body{font-family:var(--font);background:var(--bg-1);color:var(--tx-1);line-height:1.7;overflow-x:hidden;transition:background .5s,color .5s}

/* 3D Background Canvas */
#bg-canvas{position:fixed;inset:0;z-index:0;pointer-events:none}

/* Aurora / Gradient Blobs behind content */
body::before{content:'';position:fixed;top:-30%;left:-20%;width:70%;height:70%;border-radius:50%;background:radial-gradient(circle,rgba(129,140,248,.12),rgba(56,189,248,.06),transparent 70%);filter:blur(80px);animation:auroraA 12s ease-in-out infinite;pointer-events:none;z-index:0}
body::after{content:'';position:fixed;bottom:-25%;right:-15%;width:65%;height:65%;border-radius:50%;background:radial-gradient(circle,rgba(192,132,252,.1),rgba(244,114,182,.06),transparent 70%);filter:blur(80px);animation:auroraB 14s ease-in-out infinite;pointer-events:none;z-index:0}
@keyframes auroraA{0%,100%{transform:translate(0,0) scale(1)}33%{transform:translate(8%,12%) scale(1.1)}66%{transform:translate(-5%,5%) scale(.95)}}
@keyframes auroraB{0%,100%{transform:translate(0,0) scale(1)}33%{transform:translate(-10%,-8%) scale(1.05)}66%{transform:translate(6%,-4%) scale(1.1)}}
[data-theme="light"] body::before{background:radial-gradient(circle,rgba(99,102,241,.06),rgba(56,189,248,.03),transparent 70%)}
[data-theme="light"] body::after{background:radial-gradient(circle,rgba(168,85,247,.05),rgba(244,114,182,.03),transparent 70%)}

/* Skip */
.skip-link{position:absolute;top:-100px;left:16px;background:var(--ac-1);color:#fff;padding:12px 24px;border-radius:8px;z-index:9999;font-weight:600;text-decoration:none;transition:top .3s}
.skip-link:focus{top:16px}

/* Loader */
#loader{position:fixed;inset:0;z-index:10000;background:var(--bg-1);display:flex;align-items:center;justify-content:center;transition:opacity .6s}
#loader.hidden{opacity:0;pointer-events:none}
.loader-content{text-align:center}
.loader-icon{font-size:3.5rem;animation:bounce 1s infinite}
.loader-bar{width:220px;height:4px;background:rgba(255,255,255,.08);border-radius:4px;margin:24px auto;overflow:hidden}
.loader-fill{height:100%;width:0;background:var(--grad);border-radius:4px;animation:load 1.2s ease forwards}
.loader-content p{color:var(--tx-2);font-size:.85rem;margin-top:8px}
@keyframes load{to{width:100%}}
@keyframes bounce{0%,100%{transform:translateY(0)}50%{transform:translateY(-12px)}}

/* Scroll Progress */
#scroll-progress{position:fixed;top:0;left:0;height:3px;background:var(--grad);z-index:1001;width:0;transition:width .05s}

/* Nav */
#main-nav{position:fixed;top:0;left:0;right:0;z-index:100;display:flex;align-items:center;justify-content:space-between;padding:14px 40px;background:rgba(6,8,15,.8);backdrop-filter:blur(24px) saturate(180%);border-bottom:1px solid var(--brd);transition:all .3s}
[data-theme="light"] #main-nav{background:rgba(240,242,248,.85)}
.nav-brand{font-family:var(--font-d);font-weight:700;font-size:1.2rem;text-decoration:none;color:var(--tx-1)}
.nav-links{display:flex;gap:24px}
.nav-links a{color:var(--tx-2);text-decoration:none;font-size:.88rem;font-weight:500;transition:all .3s;position:relative;padding:4px 0}
.nav-links a:hover,.nav-links a.active{color:var(--tx-1)}
.nav-links a.active::after{content:'';position:absolute;bottom:0;left:0;right:0;height:2px;background:var(--grad);border-radius:2px}
.nav-actions{display:flex;gap:8px;align-items:center}
.icon-btn{background:var(--bg-card);border:1px solid var(--brd);color:var(--tx-2);width:40px;height:40px;border-radius:var(--radius-sm);cursor:pointer;display:flex;align-items:center;justify-content:center;transition:all .3s}
.icon-btn:hover{background:var(--bg-card-h);color:var(--tx-1);border-color:var(--brd-h);box-shadow:var(--glow)}
.mobile-only{display:none}
[data-theme="dark"] .icon-moon{display:none}
[data-theme="light"] .icon-sun{display:none}
[data-theme="light"] .icon-moon{display:block}

/* Search Modal */
.search-modal-content{background:var(--bg-2);border:1px solid var(--brd);border-radius:var(--radius);max-width:560px;width:100%;margin-top:-15vh;overflow:hidden;box-shadow:var(--shadow)}
.search-input-wrap{display:flex;align-items:center;gap:12px;padding:18px 22px;border-bottom:1px solid var(--brd)}
.search-input-wrap svg{color:var(--tx-2);min-width:20px}
#search-input{flex:1;background:none;border:none;color:var(--tx-1);font-size:1rem;font-family:var(--font);outline:none}
.search-input-wrap kbd{background:var(--bg-card);border:1px solid var(--brd);padding:3px 10px;border-radius:6px;font-size:.7rem;color:var(--tx-2)}
.search-results{max-height:300px;overflow-y:auto;padding:8px}
.search-results:empty::after{content:'Type to search...';display:block;padding:24px;color:var(--tx-2);text-align:center;font-size:.9rem}
.sr-item{padding:14px 18px;border-radius:var(--radius-sm);cursor:pointer;transition:all .2s}
.sr-item:hover{background:var(--bg-card-h)}
.sr-item h4{font-size:.92rem;margin-bottom:3px}
.sr-item p{font-size:.78rem;color:var(--tx-2)}

/* Hero */
#hero{min-height:100vh;display:flex;align-items:center;justify-content:center;padding:120px 40px 80px;position:relative;text-align:center;overflow:hidden;z-index:1}
.hero-glow{position:absolute;width:800px;height:800px;border-radius:50%;background:radial-gradient(circle,rgba(129,140,248,.18) 0%,rgba(192,132,252,.12) 30%,rgba(56,189,248,.06) 55%,transparent 75%);top:50%;left:50%;transform:translate(-50%,-50%);animation:pulse 8s ease-in-out infinite;pointer-events:none;z-index:0}
#hero::before{content:'';position:absolute;width:400px;height:400px;border-radius:50%;background:radial-gradient(circle,rgba(244,114,182,.12),transparent 70%);top:15%;right:5%;animation:orbFloat1 10s ease-in-out infinite;pointer-events:none}
#hero::after{content:'';position:absolute;width:350px;height:350px;border-radius:50%;background:radial-gradient(circle,rgba(56,189,248,.1),transparent 70%);bottom:10%;left:8%;animation:orbFloat2 12s ease-in-out infinite;pointer-events:none}
@keyframes pulse{0%,100%{transform:translate(-50%,-50%) scale(1);opacity:.5}50%{transform:translate(-50%,-50%) scale(1.15);opacity:1}}
@keyframes orbFloat1{0%,100%{transform:translate(0,0)}50%{transform:translate(-30px,25px)}}
@keyframes orbFloat2{0%,100%{transform:translate(0,0)}50%{transform:translate(20px,-30px)}}
.hero-content{position:relative;z-index:2;max-width:820px}
.hero-badge{display:inline-flex;align-items:center;gap:10px;padding:10px 24px;border-radius:50px;background:var(--grad-s);border:1px solid var(--brd);font-size:.85rem;font-weight:500;margin-bottom:28px;animation:fadeUp .8s ease;backdrop-filter:blur(10px)}
.badge-dot{width:8px;height:8px;border-radius:50%;background:#22c55e;animation:blink 2s infinite}
@keyframes blink{0%,100%{opacity:1}50%{opacity:.3}}
#hero h1{font-family:var(--font-d);font-size:clamp(2.5rem,5.5vw,4.2rem);font-weight:800;line-height:1.1;margin-bottom:24px;animation:fadeUp .8s .1s both;letter-spacing:-.02em}
.gradient-text{background:var(--grad);-webkit-background-clip:text;-webkit-text-fill-color:transparent;background-clip:text}
.hero-subtitle{font-size:1.15rem;color:var(--tx-2);max-width:620px;margin:0 auto 36px;animation:fadeUp .8s .2s both;line-height:1.7}
.hero-buttons{display:flex;gap:16px;justify-content:center;flex-wrap:wrap;animation:fadeUp .8s .3s both}
.btn{padding:15px 32px;border-radius:50px;font-weight:600;font-size:.92rem;text-decoration:none;border:none;cursor:pointer;transition:all .3s;font-family:var(--font);display:inline-flex;align-items:center;gap:8px}
.btn-primary{background:var(--grad);color:#fff;box-shadow:0 4px 24px rgba(129,140,248,.35)}
.btn-primary:hover{transform:translateY(-3px);box-shadow:0 8px 32px rgba(129,140,248,.5)}
.btn-primary:disabled{opacity:.5;cursor:not-allowed;transform:none}
.btn-glass{background:rgba(255,255,255,.05);color:var(--tx-1);border:1px solid var(--brd);backdrop-filter:blur(10px)}
.btn-glass:hover{background:rgba(255,255,255,.1);transform:translateY(-3px);border-color:var(--brd-h)}
.hero-stats{display:flex;gap:24px;justify-content:center;margin-top:60px;animation:fadeUp .8s .4s both}
.stat-card{text-align:center;padding:20px 28px;background:var(--bg-card);border:1px solid var(--brd);border-radius:var(--radius);backdrop-filter:blur(10px);transition:all .3s}
.stat-card:hover{transform:translateY(-4px);border-color:var(--brd-h);box-shadow:var(--glow)}
.stat-num{font-family:var(--font-d);font-size:2.2rem;font-weight:800;display:block;background:var(--grad);-webkit-background-clip:text;-webkit-text-fill-color:transparent}
.stat-label{font-size:.75rem;color:var(--tx-2);text-transform:uppercase;letter-spacing:1.5px;margin-top:4px}
@keyframes fadeUp{from{opacity:0;transform:translateY(28px)}to{opacity:1;transform:translateY(0)}}

/* Sections */
section{padding:100px 40px;max-width:1200px;margin:0 auto;position:relative;z-index:1}
.section-title{font-family:var(--font-d);font-size:clamp(1.8rem,3vw,2.8rem);font-weight:700;text-align:center;margin-bottom:14px}
.section-desc{text-align:center;color:var(--tx-2);font-size:1.05rem;margin-bottom:56px;max-width:580px;margin-left:auto;margin-right:auto}

/* Overview Flow */
.overview-flow{display:flex;align-items:center;justify-content:center;gap:6px;flex-wrap:wrap;padding:32px 0}
.flow-step{display:flex;flex-direction:column;align-items:center;gap:8px;padding:22px 18px;background:var(--bg-card);border:1px solid var(--brd);border-radius:var(--radius);min-width:110px;transition:all .4s;position:relative;cursor:default}
.flow-step:hover{transform:translateY(-6px);border-color:var(--brd-h);box-shadow:var(--glow)}
.flow-num{position:absolute;top:-10px;right:-6px;width:24px;height:24px;border-radius:50%;background:var(--grad);font-size:.65rem;font-weight:700;display:flex;align-items:center;justify-content:center;color:#fff}
.flow-icon{font-size:2rem}
.flow-step span{font-size:.8rem;font-weight:600;color:var(--tx-2)}
.flow-connector{width:32px;height:2px;background:var(--grad);border-radius:2px;flex-shrink:0}

/* Timeline */
.timeline-container{position:relative;max-width:720px;margin:0 auto}
.timeline-line{position:absolute;left:25px;top:0;bottom:0;width:3px;background:linear-gradient(to bottom,var(--ac-1),var(--ac-2),var(--ac-4));border-radius:3px;opacity:.6}
.timeline-item{display:flex;gap:28px;margin-bottom:44px;position:relative;opacity:0;transform:translateX(-40px);transition:all .7s cubic-bezier(.16,1,.3,1)}
.timeline-item.visible{opacity:1;transform:translateX(0)}
.timeline-dot{width:52px;height:52px;min-width:52px;border-radius:50%;background:var(--grad);display:flex;align-items:center;justify-content:center;font-weight:700;font-size:1rem;z-index:2;box-shadow:0 0 24px rgba(129,140,248,.4);transition:transform .3s}
.timeline-item:hover .timeline-dot{transform:scale(1.1)}
.timeline-card{background:var(--bg-card);border:1px solid var(--brd);border-radius:var(--radius);padding:28px 32px;flex:1;backdrop-filter:blur(12px);transition:all .3s}
.timeline-card:hover{background:var(--bg-card-h);transform:translateY(-4px);box-shadow:var(--shadow);border-color:var(--brd-h)}
.card-icon{font-size:1.8rem;margin-bottom:12px}
.timeline-card h3{font-family:var(--font-d);font-size:1.15rem;margin-bottom:8px}
.timeline-card p{color:var(--tx-2);font-size:.9rem;line-height:1.65}
.card-tag{display:inline-block;margin-top:14px;padding:5px 16px;border-radius:50px;background:var(--grad-s);font-size:.73rem;font-weight:600;color:var(--ac-2);letter-spacing:.5px}

/* Topics */
.topics-grid{display:grid;grid-template-columns:repeat(auto-fit,minmax(320px,1fr));gap:24px}
.topic-card{background:var(--bg-card);border:1px solid var(--brd);border-radius:var(--radius);padding:36px;cursor:pointer;transition:all .4s;position:relative;overflow:hidden}
.topic-glow{position:absolute;width:200px;height:200px;border-radius:50%;background:radial-gradient(circle,rgba(129,140,248,.15),transparent 70%);top:-60px;right:-60px;opacity:0;transition:opacity .4s;pointer-events:none}
.topic-card:hover .topic-glow,.topic-card:focus-visible .topic-glow{opacity:1}
.topic-card:hover,.topic-card:focus-visible{transform:translateY(-8px);box-shadow:var(--shadow);border-color:var(--brd-h);outline:none}
.topic-card>*:not(.topic-glow){position:relative;z-index:1}
.topic-icon{font-size:2.5rem;margin-bottom:16px;display:block}
.topic-card h3{font-family:var(--font-d);font-size:1.15rem;margin-bottom:10px}
.topic-card p{color:var(--tx-2);font-size:.88rem;line-height:1.5}

/* Modal */
.modal-overlay{position:fixed;inset:0;z-index:200;background:rgba(0,0,0,.65);backdrop-filter:blur(12px);display:flex;align-items:center;justify-content:center;opacity:0;pointer-events:none;transition:all .3s;padding:20px}
.modal-overlay.active{opacity:1;pointer-events:all}
.modal-content{background:var(--bg-2);border:1px solid var(--brd);border-radius:var(--radius);padding:44px;max-width:660px;width:100%;max-height:80vh;overflow-y:auto;transform:scale(.9) translateY(24px);transition:all .4s cubic-bezier(.16,1,.3,1);position:relative;box-shadow:var(--shadow)}
.modal-overlay.active .modal-content{transform:scale(1) translateY(0)}
.modal-close{position:absolute;top:18px;right:22px;background:none;border:none;color:var(--tx-2);font-size:2rem;cursor:pointer;transition:all .3s;line-height:1}
.modal-close:hover{color:var(--tx-1);transform:rotate(90deg)}
#modal-body h3{font-family:var(--font-d);font-size:1.5rem;margin-bottom:18px}
#modal-body ul{padding-left:22px;margin:14px 0}
#modal-body li{color:var(--tx-2);margin-bottom:10px;font-size:.93rem;line-height:1.6}
#modal-body p{color:var(--tx-2);margin-bottom:14px;font-size:.93rem}
#modal-body .modal-icon{font-size:2.8rem;margin-bottom:14px;display:block}

/* Quiz */
.quiz-container{max-width:660px;margin:0 auto}
#quiz-progress-bar{height:6px;background:var(--brd);border-radius:6px;overflow:hidden;margin-bottom:18px}
#quiz-progress-fill{height:100%;background:var(--grad);width:10%;transition:width .5s ease;border-radius:6px}
.quiz-counter{text-align:center;font-size:.85rem;color:var(--tx-2);margin-bottom:22px;font-weight:500}
.quiz-card{background:var(--bg-card);border:1px solid var(--brd);border-radius:var(--radius);padding:40px;margin-bottom:22px;backdrop-filter:blur(10px)}
.quiz-card h3{font-family:var(--font-d);font-size:1.2rem;margin-bottom:28px;line-height:1.5}
.quiz-options{display:flex;flex-direction:column;gap:14px}
.quiz-opt{padding:18px 24px;border-radius:var(--radius-sm);background:var(--bg-card-h);border:2px solid var(--brd);cursor:pointer;transition:all .3s;font-size:.95rem;text-align:left;font-family:var(--font);color:var(--tx-1)}
.quiz-opt:hover:not(.correct):not(.wrong){border-color:var(--ac-1);background:rgba(129,140,248,.08);transform:translateX(4px)}
.quiz-opt.selected{border-color:var(--ac-1);background:rgba(129,140,248,.12)}
.quiz-opt.correct{border-color:#22c55e;background:rgba(34,197,94,.1);color:#22c55e}
.quiz-opt.wrong{border-color:#ef4444;background:rgba(239,68,68,.08);color:#ef4444}
.quiz-actions{text-align:center}
.quiz-result{text-align:center;padding:44px}
.result-icon{font-size:4.5rem;margin-bottom:18px}
.quiz-result h3{font-family:var(--font-d);font-size:1.6rem;margin-bottom:10px}
.quiz-result p{color:var(--tx-2);margin-bottom:28px;font-size:1rem}
.result-score{font-family:var(--font-d);font-size:3.5rem;font-weight:800;background:var(--grad);-webkit-background-clip:text;-webkit-text-fill-color:transparent;margin-bottom:28px}

/* Chat */
.faq-container{max-width:720px;margin:0 auto}
.quick-questions{display:flex;flex-wrap:wrap;gap:10px;margin-bottom:28px;justify-content:center}
.qq-btn{padding:10px 20px;border-radius:50px;background:var(--bg-card);border:1px solid var(--brd);color:var(--tx-2);font-size:.82rem;cursor:pointer;transition:all .3s;font-family:var(--font)}
.qq-btn:hover{background:var(--bg-card-h);color:var(--tx-1);border-color:var(--brd-h);transform:translateY(-2px)}
.chat-area{background:var(--bg-card);border:1px solid var(--brd);border-radius:var(--radius);padding:28px;min-height:300px;max-height:440px;overflow-y:auto;margin-bottom:18px;display:flex;flex-direction:column;gap:18px;backdrop-filter:blur(10px)}
.chat-msg{display:flex;gap:12px;animation:fadeUp .4s ease}
.chat-msg.user-msg{flex-direction:row-reverse}
.msg-avatar{font-size:1.5rem;min-width:38px;text-align:center}
.msg-bubble{padding:16px 20px;border-radius:18px;max-width:82%;font-size:.9rem;line-height:1.65}
.bot-msg .msg-bubble{background:rgba(129,140,248,.08);border:1px solid rgba(129,140,248,.15)}
.user-msg .msg-bubble{background:var(--grad);color:#fff}
.typing-indicator{display:flex;gap:4px;padding:16px 20px}
.typing-dot{width:8px;height:8px;border-radius:50%;background:var(--ac-1);animation:typingBounce 1.4s infinite}
.typing-dot:nth-child(2){animation-delay:.2s}
.typing-dot:nth-child(3){animation-delay:.4s}
@keyframes typingBounce{0%,60%,100%{transform:translateY(0);opacity:.4}30%{transform:translateY(-8px);opacity:1}}
.chat-input-area{display:flex;gap:12px}
#chat-input{flex:1;padding:16px 24px;border-radius:50px;background:var(--bg-card);border:1px solid var(--brd);color:var(--tx-1);font-size:.92rem;font-family:var(--font);outline:none;transition:all .3s}
#chat-input:focus{border-color:var(--ac-1);box-shadow:0 0 20px rgba(129,140,248,.1)}
#chat-send{width:52px;height:52px;padding:0;border-radius:50%;display:flex;align-items:center;justify-content:center}

/* Back to top */
.back-to-top{position:fixed;bottom:32px;right:32px;width:50px;height:50px;border-radius:50%;background:var(--grad);color:#fff;border:none;cursor:pointer;display:flex;align-items:center;justify-content:center;box-shadow:0 4px 20px rgba(129,140,248,.4);opacity:0;transform:translateY(20px);transition:all .3s;z-index:90}
.back-to-top.visible{opacity:1;transform:translateY(0)}
.back-to-top:hover{transform:translateY(-4px);box-shadow:0 8px 30px rgba(129,140,248,.5)}

/* Footer */
footer{padding:64px 40px 40px;text-align:center;border-top:1px solid var(--brd);background:rgba(0,0,0,.2);position:relative;z-index:1}
[data-theme="light"] footer{background:rgba(0,0,0,.02)}
.footer-brand{font-size:1.3rem;margin-bottom:10px}
footer p{color:var(--tx-2);font-size:.9rem}
.footer-links{display:flex;gap:24px;justify-content:center;margin:24px 0}
.footer-links a{color:var(--tx-2);text-decoration:none;font-size:.85rem;transition:color .3s}
.footer-links a:hover{color:var(--tx-1)}
.footer-note{font-size:.78rem!important;margin-top:18px;opacity:.7}
.footer-copy{font-size:.73rem!important;margin-top:8px;opacity:.5}

:focus-visible{outline:2px solid var(--ac-1);outline-offset:3px;border-radius:4px}
::-webkit-scrollbar{width:6px}
::-webkit-scrollbar-track{background:transparent}
::-webkit-scrollbar-thumb{background:rgba(129,140,248,.25);border-radius:3px}

@media(max-width:768px){
  #main-nav{padding:12px 16px}
  .nav-links{display:none;position:absolute;top:100%;left:0;right:0;background:var(--bg-2);padding:20px;flex-direction:column;gap:14px;border-bottom:1px solid var(--brd);backdrop-filter:blur(20px)}
  .nav-links.open{display:flex}
  .mobile-only{display:flex}
  section{padding:60px 16px}
  .hero-stats{flex-direction:column;gap:12px;align-items:center}
  .stat-card{width:100%;max-width:200px}
  .topics-grid{grid-template-columns:1fr}
  .overview-flow{gap:8px}
  .flow-step{min-width:70px;padding:16px 10px}
  .flow-connector{width:16px}
}
@media print{#main-nav,#loader,#scroll-progress,#bg-canvas,.back-to-top,.hero-buttons,.chat-input-area,.quick-questions,#quiz{display:none!important}body{background:#fff;color:#000}}