*{box-sizing:border-box}
:root{
  --purple:#6d5dfc;--deep:#4b3cc4;--pink:#f36aa5;--blue:#43a7e8;
  --ink:#242342;--muted:#73728a;--bg:#faf9ff;--card:#fff;--line:#e8e5f2;
}
html{scroll-behavior:smooth}
body{margin:0;background:var(--bg);color:var(--ink);font-family:system-ui,-apple-system,BlinkMacSystemFont,"Segoe UI",sans-serif;line-height:1.6}
a{text-decoration:none;color:inherit}
button{font:inherit}
.topbar{height:66px;padding:10px 18px;background:rgba(255,255,255,.93);backdrop-filter:blur(12px);border-bottom:1px solid var(--line);display:flex;align-items:center;justify-content:space-between;position:sticky;top:0;z-index:50}
.brand{display:flex;align-items:center;gap:10px}.brand-icon{width:40px;height:40px;border-radius:13px;background:linear-gradient(135deg,var(--purple),#9c7bff);color:#fff;display:grid;place-items:center;font-size:22px;box-shadow:0 8px 20px #6d5dfc30}.brand strong{display:block;font-size:.98rem}.brand small{display:block;color:var(--muted);font-size:.7rem}
.menu-btn{border:1px solid var(--line);background:#fff;border-radius:10px;padding:7px 10px;color:var(--ink);cursor:pointer}
.nav{display:none;position:sticky;top:66px;z-index:49;background:#fff;border-bottom:1px solid var(--line);padding:8px 18px;gap:8px}.nav.open{display:flex}.nav a{padding:7px 11px;border-radius:9px;font-size:.9rem}.nav a:hover{background:#f0eeff;color:var(--purple)}
main{max-width:900px;margin:auto}
.hero{position:relative;overflow:hidden;min-height:520px;padding:58px 25px 40px;background:linear-gradient(135deg,#f1efff 0%,#fff 54%,#f5efff 100%);display:grid;grid-template-columns:1.05fr .95fr;align-items:center}
.hero-content{position:relative;z-index:3}.welcome{font-size:.76rem;letter-spacing:.13em;font-weight:850;color:var(--purple);margin-bottom:10px}
h1{font-size:clamp(3rem,8vw,5.3rem);line-height:.96;letter-spacing:-.06em;margin:0 0 20px}.hero h1 span{background:linear-gradient(90deg,var(--purple),var(--pink));-webkit-background-clip:text;background-clip:text;color:transparent}
.hero-text{font-size:1.12rem;color:#5d5b72;max-width:460px;margin-bottom:25px}.start-btn{display:inline-flex;align-items:center;gap:15px;background:linear-gradient(135deg,var(--purple),#8875ff);color:#fff;padding:13px 18px;border-radius:14px;font-weight:800;box-shadow:0 12px 26px #6d5dfc35;transition:.2s}.start-btn span{font-size:1.25rem}.start-btn:hover{transform:translateY(-2px)}
.hero-art{height:360px;position:relative}.planet{position:absolute;border-radius:50%}.planet-one{width:145px;height:145px;right:12%;top:19%;background:linear-gradient(145deg,#8173ff,#c2a6ff);box-shadow:inset -15px -16px 30px #4934aa45,0 20px 50px #6d5dfc22}.planet-two{width:38px;height:38px;right:3%;top:7%;background:linear-gradient(145deg,#ff9bc5,#f36aa5)}.orbit{position:absolute;border:2px solid #8e7dfd45;border-radius:50%;transform:rotate(-25deg)}.orbit-one{width:270px;height:115px;right:-3%;top:24%}.orbit-two{width:340px;height:155px;right:-10%;top:17%;transform:rotate(18deg)}
.atom-symbol{position:absolute;right:27%;top:35%;width:115px;height:115px;display:grid;place-items:center}.atom-symbol i{position:absolute;width:105px;height:43px;border:2px solid #6d5dfc80;border-radius:50%}.atom-symbol i:nth-child(2){transform:rotate(60deg)}.atom-symbol i:nth-child(3){transform:rotate(-60deg)}.nucleus-dot{width:34px;height:34px;border-radius:50%;display:grid;place-items:center;background:#ffcb69;color:#fff;z-index:2;box-shadow:0 6px 20px #ffcb6950}
.floating-card{position:absolute;background:#fff;border:1px solid #e5e1f3;border-radius:13px;padding:9px 12px;box-shadow:0 12px 30px #40307016;font-size:1.15rem}.floating-card span{display:block;font-size:.68rem;color:var(--muted);font-weight:700}.card-one{left:2%;top:24%}.card-two{right:2%;bottom:13%}.spark{position:absolute;color:#9a8cff;font-size:1.5rem}.s1{left:8%;top:8%}.s2{right:5%;bottom:7%}
.quote{display:flex;gap:12px;align-items:center;margin:0 18px;padding:20px 0;border-bottom:1px solid var(--line)}.quote-mark{font-size:3.3rem;line-height:.7;color:var(--pink)}.quote p{font-weight:750;margin:0}.quote small{color:var(--muted)}.quote strong{color:var(--purple)}
.section{padding:52px 20px}.section-label{font-size:.68rem;letter-spacing:.12em;font-weight:850;color:var(--purple)}.section h2{font-size:2rem;line-height:1.15;margin:5px 0 8px;letter-spacing:-.035em}.section-intro{color:var(--muted);max-width:650px;margin-top:0}
.topic-grid{display:grid;grid-template-columns:1fr 1fr;gap:17px;margin-top:25px}.topic-card{border-radius:21px;overflow:hidden;border:1px solid var(--line);background:#fff;box-shadow:0 12px 30px #3e2d6d0b;transition:.25s}.topic-card:hover{transform:translateY(-5px);box-shadow:0 18px 38px #3e2d6d17}.topic-top{height:150px;position:relative;display:flex;align-items:center;justify-content:center}.mixtures .topic-top{background:linear-gradient(135deg,#e5f8ff,#d9efff)}.atoms .topic-top{background:linear-gradient(135deg,#eee9ff,#e2dbff)}.topic-icon{font-size:4rem;filter:drop-shadow(0 8px 12px #3c2c6b1c)}.topic-number{position:absolute;right:14px;top:12px;font-size:.72rem;font-weight:850;color:#fff;background:#ffffff35;padding:5px 8px;border-radius:20px}.mixtures .topic-number{color:#27749c;background:#fff8}.atoms .topic-number{color:#5143b5;background:#fff8}
.topic-content{padding:19px}.topic-tag{font-size:.63rem;font-weight:850;letter-spacing:.1em;color:var(--muted)}.topic-content h3{font-size:1.45rem;line-height:1.15;margin:7px 0}.topic-content p{color:var(--muted);font-size:.92rem;min-height:58px}.topic-chips{display:flex;gap:5px;flex-wrap:wrap;margin:12px 0}.topic-chips span{font-size:.69rem;padding:5px 7px;border-radius:7px;background:#f4f3fa;color:#5e5a70}.topic-btn{display:flex;justify-content:space-between;align-items:center;padding:10px 12px;border-radius:11px;font-size:.85rem;font-weight:800}.mixtures .topic-btn{background:#eaf7ff;color:#247ca7}.atoms .topic-btn{background:#efecff;color:#5849ca}
.journey{background:#f7f5ff;border-radius:25px;margin:0 18px;padding:35px 20px}.journey-grid{display:grid;grid-template-columns:repeat(4,1fr);gap:10px;margin-top:22px}.journey-step{background:#fff;border:1px solid #e7e2fa;border-radius:14px;padding:13px}.journey-icon{font-size:1.5rem;margin-bottom:7px}.journey-step b{font-size:.9rem}.journey-step p{font-size:.78rem;color:var(--muted);margin:3px 0}
.tip-card{display:flex;gap:17px;align-items:flex-start;background:#fff;border:1px solid var(--line);border-radius:20px;padding:22px;box-shadow:0 10px 25px #3e2d6d0b}.tip-icon{font-size:2.4rem}.tip-card h2{font-size:1.45rem}.tip-card p{color:var(--muted);margin-bottom:0}.finish{text-align:center;margin:0 18px 35px;border-radius:25px;padding:40px 18px;background:linear-gradient(135deg,#5a49d9,#856cf5);color:#fff;box-shadow:0 18px 40px #5a49d934}.finish-stars{letter-spacing:10px;opacity:.8}.finish h2{font-size:2rem;line-height:1.1;margin:13px 0 7px}.finish p{opacity:.85;margin-top:0}.start-btn.light{background:#fff;color:#5949d5;box-shadow:none}
footer{text-align:center;padding:25px 18px;color:var(--muted);font-size:.82rem}.footer-brand{font-weight:800;color:var(--purple)}footer p{margin:4px}

@media(max-width:700px){.hero{grid-template-columns:1fr;min-height:0;padding-top:43px}.hero-art{height:235px;margin-top:12px}.planet-one{right:20%;top:10%;width:120px;height:120px}.orbit-one{right:4%;top:16%;width:250px}.orbit-two{right:-7%;top:7%;width:300px}.atom-symbol{right:32%;top:30%;transform:scale(.8)}.card-one{left:7%;top:10%}.card-two{right:7%;bottom:5%}.topic-grid{grid-template-columns:1fr}.topic-content p{min-height:0}.journey-grid{grid-template-columns:1fr 1fr}}
@media(max-width:430px){.hero{padding-left:18px;padding-right:18px}.hero-art{height:220px}.journey{margin:0 12px}.journey-grid{grid-template-columns:1fr}.section{padding-left:18px;padding-right:18px}.finish{margin-left:12px;margin-right:12px}}