:root{font-family:Arial,Helvetica,sans-serif;color:#14353b;background:#f8f5ec;--ink:#14353b;--teal:#126b62;--paper:#f8f5ec;--mint:#d9eee1;--orange:#ef733e;--yellow:#f6d46c;--border:#dbe1d6;--white:#fffdf7;--muted:#52676a}
*{box-sizing:border-box}html{scroll-behavior:smooth}body{margin:0;min-width:320px;line-height:1.5}button,input,select{font:inherit}button{cursor:pointer}a{color:var(--teal)}button:focus-visible,a:focus-visible,input:focus-visible,select:focus-visible{outline:3px solid #dc652e;outline-offset:4px}.skip-link{position:absolute;left:-100vw;top:0;padding:12px;background:white;z-index:12}.skip-link:focus{left:12px}.shell{max-width:1180px;min-height:100dvh;margin:auto;padding:16px max(12px,env(safe-area-inset-right)) calc(12px + env(safe-area-inset-bottom)) max(12px,env(safe-area-inset-left));display:flex;flex-direction:column;gap:12px}.topbar{display:flex;align-items:center;justify-content:space-between;gap:12px;background:#14353b;color:white;border-radius:18px;padding:11px 16px}.brand{display:flex;align-items:center;gap:12px;color:white;text-decoration:none;min-width:0}.brand img{flex:none}.brand span{display:flex;flex-direction:column;line-height:1.12}.brand strong{font-size:18px;letter-spacing:.04em}.brand small{font-size:11px;letter-spacing:.12em;color:#f6d46c}.hud{display:flex;gap:8px;flex-wrap:wrap;justify-content:flex-end}.hud span{border-radius:12px;background:#285159;padding:8px 10px;font-weight:bold;font-size:14px}.tabs{display:flex;gap:6px;background:#e6ece4;border-radius:18px;padding:6px;overflow-x:auto;scrollbar-width:thin}.tabs button{border:0;border-radius:12px;background:transparent;color:var(--ink);padding:10px 14px;font-size:15px;font-weight:750;white-space:nowrap;min-height:44px}.tabs button[aria-current=page]{background:var(--white);box-shadow:0 2px 0 #cad5cd}#main{flex:1}.panel{background:var(--white);border:1px solid var(--border);border-radius:24px;padding:24px;margin-bottom:12px;box-shadow:0 4px 0 #eaeade;min-width:0}.panel h1{margin:0 0 12px;font-size:clamp(27px,4vw,40px);line-height:1.18;letter-spacing:-.025em}.panel h2{font-size:24px;margin:0 0 12px;line-height:1.25}.panel h3{margin:8px 0;font-size:18px}.eyebrow{letter-spacing:.12em;font-size:12px;font-weight:900;text-transform:uppercase;color:#126b62;margin-bottom:8px}.subtitle{font-size:clamp(16px,2vw,20px);color:#40585a;max-width:720px;margin:0 0 18px}.small{font-size:13px;color:var(--muted)}.btn{display:inline-flex;align-items:center;justify-content:center;gap:8px;min-height:48px;border-radius:13px;padding:11px 18px;border:2px solid transparent;font-weight:800;text-align:center;text-decoration:none}.btn-primary{background:var(--orange);color:#14353b}.btn-dark{background:var(--ink);color:white}.btn-secondary{background:white;border-color:var(--border);color:var(--ink)}.btn:disabled{opacity:.5;cursor:not-allowed}.btn-row{display:flex;gap:10px;flex-wrap:wrap;margin-top:16px}.hero-scene{border-radius:20px;background:linear-gradient(180deg,#c4e5df 0 68%,#cfe1af 68% 100%);position:relative;overflow:hidden;min-height:245px;display:flex;align-items:center;gap:20px;padding:22px}.hero-scene:before{content:'☁️     ☁️';position:absolute;right:25px;top:10px;opacity:.55;font-size:34px;letter-spacing:45px}.hero-copy{position:relative;z-index:1;max-width:540px}.hero-copy .eyebrow{color:#16635d}.hero-figures{position:relative;margin:auto;z-index:1;display:flex;align-items:flex-end}.pip-svg{width:min(24vw,150px);min-width:85px;height:auto;filter:drop-shadow(0 4px 0 #b0c9b4)}.hero-svg{width:min(27vw,160px);min-width:90px;height:auto;filter:drop-shadow(0 4px 0 #b0c9b4)}.stat-grid{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:12px;margin-top:14px}.stat{padding:14px;border-radius:16px;background:#eaf2e6;text-align:center}.stat strong{display:block;font-size:26px}.stat span{font-size:13px}.world-grid{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:13px}.world-card{border:2px solid var(--border);border-radius:18px;background:#fff;padding:14px;text-align:left;color:var(--ink);min-height:156px;display:flex;flex-direction:column;gap:9px;box-shadow:0 3px 0 #e2e6de;transition:transform .12s}.world-card:hover{transform:translateY(-2px)}.world-card.selected{border-color:var(--teal);box-shadow:0 3px 0 #a9c8b8}.world-card .world-icon{font-size:30px}.world-card strong{font-size:19px}.world-card .year{font-size:12px;letter-spacing:.06em;text-transform:uppercase;font-weight:bold}.progress{height:10px;border-radius:15px;background:#e5eae6;overflow:hidden;width:100%}.progress div{height:100%;background:var(--teal);border-radius:12px}.map-head{display:flex;justify-content:space-between;gap:16px;align-items:flex-start;flex-wrap:wrap}.quest-track{position:relative;display:grid;grid-template-columns:repeat(5,minmax(0,1fr));gap:13px;margin-top:18px}.quest{position:relative;background:white;min-height:136px;border-radius:18px;border:2px solid #dbe1d6;padding:12px 8px;text-align:center;color:var(--ink);display:flex;align-items:center;flex-direction:column;justify-content:center;gap:8px;box-shadow:0 4px 0 #e2e6de}.quest:hover{border-color:var(--teal)}.quest:before{content:'';position:absolute;top:43px;left:-18px;width:17px;height:6px;background:#dfc98c}.quest:nth-child(5n+1):before{display:none}.quest .q-figure{font-size:30px}.quest strong{font-size:14px;line-height:1.18}.quest .tag{font-size:11px;background:#e8f3e8;padding:3px 8px;border-radius:50px}.quest.done{border-color:#5a9f82;background:#eef9ef}.quest.done .tag{background:#d4ecd4}.quest-map{border-radius:18px;padding:16px;background:linear-gradient(145deg,#d5e7d8,#eae0bc);margin-top:14px}.callout{padding:13px 16px;background:#e9f4ec;border-left:5px solid var(--teal);border-radius:12px;font-size:15px}.callout.warn{background:#fff1dc;border-color:#bf762c}.tagline{font-size:13px;letter-spacing:.02em;color:var(--muted);font-weight:700}.lesson-shell{display:grid;grid-template-columns:minmax(0,1.5fr) minmax(220px,.8fr);gap:18px}.lesson-card{background:#fff;border:1px solid var(--border);border-radius:18px;padding:20px}.lesson-art{background:#dceadd;border-radius:18px;padding:12px;min-height:300px;display:flex;align-items:center;justify-content:center;flex-direction:column;text-align:center;gap:10px}.lesson-art .big-icon{font-size:96px}.question{font-size:clamp(19px,2.5vw,27px);font-weight:800;margin:15px 0}.answers{display:grid;gap:10px;margin-top:18px}.answer{background:white;border:2px solid #a9c9b8;border-radius:14px;padding:14px 16px;min-height:54px;text-align:left;font-weight:700;color:var(--ink)}.answer:hover{background:#f0f8f3}.answer.correct{background:#d7edd7;border-color:#39825f}.answer.incorrect{background:#fbeecd;border-color:#dcaa57}.feedback{border:2px solid #d5e8d3;background:#f1f9ed;border-radius:13px;padding:13px;margin-top:15px}.feedback.warn{border-color:#f5d096;background:#fff7e9}.stage{display:flex;gap:7px;align-items:center;margin-bottom:14px}.stage .node{background:#e5ebe4;padding:6px 12px;border-radius:30px;font-size:12px;font-weight:bold}.stage .node.active{background:var(--teal);color:white}.stage .node.done{background:#d9eee1}.activity-grid{display:grid;grid-template-columns:minmax(0,1.2fr) minmax(240px,.8fr);gap:16px}.field{display:block;font-weight:700;margin:10px 0 5px}.field select,.field input{border:2px solid #cbd6cf;border-radius:12px;background:white;width:100%;min-height:48px;padding:10px;color:var(--ink)}.selector-row{display:grid;grid-template-columns:1fr 1fr;gap:12px}.choices{display:flex;flex-wrap:wrap;gap:8px}.choices button{border:2px solid #b5cbc0;background:white;border-radius:12px;padding:10px 12px;font-weight:bold;min-height:44px;color:var(--ink)}.choices button.selected{background:#d9eee1;border-color:#126b62}.reveal{background:#eef7ed;border:2px solid #98c6a7;border-radius:14px;padding:15px;margin-top:15px}.reveal h3{margin-top:0}.equation{font-size:17px;font-weight:bold;overflow-wrap:anywhere;background:#f1f6ee;padding:12px;border-radius:10px;margin:12px 0}.particle-stage{position:relative;height:235px;border:3px solid #87b8ca;border-top:0;border-radius:0 0 18px 18px;background:linear-gradient(#fbffff,#eaf9ff);overflow:hidden}.particle{position:absolute;width:19px;height:19px;background:#63b4ce;border-radius:100%;box-shadow:inset -3px -3px 0 #318ba7;border:1px solid #207b98;transition:top .4s,left .4s}.particle.solid{background:#67b8dc}.particle.gas{background:#95d2de}.periodic-scroll{overflow-x:auto;padding:5px 2px 20px}.ptable{display:grid;grid-template-columns:repeat(18, minmax(48px,1fr));grid-auto-rows:57px;gap:4px;min-width:940px}.elem{background:#e6f2e8;border:1px solid #adc8b5;border-radius:6px;text-align:center;display:flex;flex-direction:column;justify-content:center;align-items:center;color:#14353b;min-width:0;padding:2px}.elem:hover{outline:2px solid #126b62}.elem b{font-size:17px;line-height:1.1}.elem small{font-size:10px;line-height:1.1}.elem .atomic{font-size:9px}.elem.gas{background:#d7e9f4}.elem.liquid{background:#f4d8a9}.elem.not-established{background:#e8e6ef}.elem.matched{border:3px solid #136b62}.periodic-key{display:flex;gap:10px;flex-wrap:wrap;font-size:13px}.periodic-key span:before{content:'● ';color:#126b62}.element-detail{border:2px solid var(--border);border-radius:17px;padding:16px;background:#f2f7ed}.element-detail strong{font-size:50px;display:block}.element-detail p{margin:6px 0}.flex-between{display:flex;justify-content:space-between;align-items:center;gap:12px;flex-wrap:wrap}.num{font-variant-numeric:tabular-nums}.coeff{width:64px;min-height:45px;background:white;border-radius:9px;border:2px solid var(--teal);color:var(--ink);font-weight:bold;font-size:18px}.formula-piece{display:inline-flex;align-items:center;gap:5px;margin:5px}.formula-piece b{font-size:23px}.balance-counts{display:flex;gap:12px;flex-wrap:wrap}.balance-counts span{background:#eaf4ee;padding:7px 12px;border-radius:10px}.adult-grid{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:15px}.curriculum-list{display:grid;gap:9px;max-height:420px;overflow-y:auto}.curriculum-list div{border:1px solid #dbe1d6;border-radius:8px;padding:8px 10px;background:white}footer{font-size:12px;color:#637272;display:flex;justify-content:space-between;gap:8px;flex-wrap:wrap;padding:0 6px 8px}.helper-icon{display:inline-flex;align-items:center;justify-content:center;width:34px;height:34px;border-radius:9px;background:#e6eee2}.checkmark{color:#1b754f}.hide{display:none!important}
@media(max-width:750px){.shell{padding-top:8px}.panel{padding:16px;border-radius:19px}.hero-scene{min-height:265px;padding:15px;flex-direction:column;align-items:stretch;gap:0}.hero-figures{position:absolute;right:12px;bottom:7px;opacity:.45}.hero-copy{max-width:100%}.hero-copy .subtitle{max-width:75%}.world-grid{grid-template-columns:repeat(2,minmax(0,1fr));gap:10px}.world-card{min-height:146px}.quest-track{grid-template-columns:repeat(2,minmax(0,1fr));gap:10px}.quest:before{display:none}.lesson-shell,.activity-grid,.adult-grid{grid-template-columns:1fr}.lesson-art{min-height:170px}.lesson-art .big-icon{font-size:60px}.stat-grid{gap:6px}.stat{padding:10px 5px}.stat strong{font-size:21px}.selector-row{grid-template-columns:1fr 1fr}.tabs button{padding:8px 11px;font-size:14px}.brand strong{font-size:15px}.brand small{font-size:9px}.hud span{font-size:12px;padding:7px}.hero-scene .pip-svg{width:98px}.hero-scene .hero-svg{width:108px}}
@media(max-width:420px){.tabs button span{display:none}.tabs button{font-size:22px;padding:9px 13px}.world-card strong{font-size:16px}.world-card{padding:10px}.quest-track{grid-template-columns:repeat(2,minmax(0,1fr))}.hud span{font-size:12px}.hero-copy .subtitle{max-width:82%}.hero-figures{opacity:.25}}
@media(prefers-reduced-motion:reduce){*,*:before,*:after{animation:none!important;transition:none!important;scroll-behavior:auto!important}}

.reduce-motion *, .reduce-motion *:before, .reduce-motion *:after{animation:none!important;transition:none!important;scroll-behavior:auto!important}

.reactor-zone{display:flex;align-items:center;justify-content:center;gap:7px;flex-wrap:wrap;padding:16px 6px;background:linear-gradient(180deg,#f0f8f3,#e2f1ea);border-radius:15px;margin:14px 0;min-height:164px}
.input-beaker{display:flex;flex-direction:column;align-items:center;justify-content:center;gap:4px;max-width:120px;font-size:12px;text-align:center;font-weight:bold}
.input-beaker .flask{font-size:38px;line-height:1.3}.flow-arrow{font-size:26px;color:#126b62;font-weight:bold}
.reactor-beaker{position:relative;height:130px;width:105px;border:5px solid #26847b;border-top:0;border-radius:0 0 22px 22px;background:#fafdff;overflow:hidden;display:flex;flex-direction:column;align-items:center;justify-content:flex-end}
.reactor-beaker:before{content:'';position:absolute;left:-8px;top:0;right:-8px;border-top:6px solid #26847b;border-radius:25px}
.reactor-liquid{position:absolute;bottom:0;left:0;right:0;height:62%;background:#99d1dd;opacity:.8}
.reactor-beaker.mixture .reactor-liquid{background:linear-gradient(#f8d780 0 45%,#8dcee0 45% 100%)}
.reactor-beaker.reaction .reactor-liquid{background:#b4d2aa}
.reactor-beaker.dissolve .reactor-liquid{background:#a4cfe2}
.reaction-bubbles{font-size:22px;color:#0c6a6b;position:relative;z-index:1;text-align:center;height:57%;display:flex;align-items:center}
.caption-reaction{font-size:9px;text-align:center;background:#14353b;color:white;padding:4px 5px;letter-spacing:.03em;width:100%;position:relative;z-index:2;min-height:22px}
@media(max-width:410px){.reactor-zone{gap:3px}.input-beaker{max-width:90px;font-size:10px}.input-beaker .flask{font-size:30px}.flow-arrow{font-size:18px}.reactor-beaker{width:87px}}

/* Discovery workshop: responsive, no compulsory dragging */
.discovery-tabs{display:flex;gap:8px;overflow-x:auto;padding:7px 0 20px;margin-bottom:10px;scrollbar-width:thin}.discovery-chip{padding:10px 13px;min-height:48px;white-space:nowrap;background:white;border:2px solid #dbe1d6;border-radius:14px;font-weight:bold;color:#14353b}.discovery-chip.selected{border-color:#126b62;background:#d9eee1}.discovery-workspace select,.discovery-workspace input[type=number]{display:block;width:100%;min-height:48px;border:2px solid #abcbb9;border-radius:12px;padding:10px;color:#14353b;background:white}.discovery-workspace input[type=range]{width:100%;min-height:44px;accent-color:#126b62}.discovery-workspace h2{margin-top:0}.atom-bank{display:flex;flex-wrap:wrap;gap:12px;margin:20px 0}.atom-adjust{display:flex;gap:7px;align-items:center;background:#f0f7ef;border-radius:14px;padding:7px}.atom-adjust button{min-height:44px;min-width:44px;border:2px solid #a2c9b0;background:white;border-radius:11px;font-size:23px;font-weight:bold}.atom-ball{width:46px;height:46px;border-radius:50%;display:inline-flex;align-items:center;justify-content:center;background:#b1e0e9;border:2px solid #478b9d;font-size:20px;font-weight:900}.atom-O{background:#f6b3a3;border-color:#ce7661}.atom-H{background:#f7f5ef;border-color:#aab0b0}.atom-C{background:#bcc6ca;border-color:#66767b}.atom-N{background:#c2baf4;border-color:#7770b0}.molecule-stage{min-height:132px;display:flex;flex-wrap:wrap;align-items:center;justify-content:center;gap:7px;background:#e7f3e9;border-radius:18px;padding:15px}.atom-diagram{height:200px;margin:16px auto;border-radius:50%;max-width:230px;border:3px dashed #78adad;display:flex;align-items:center;justify-content:center;position:relative;background:radial-gradient(circle,#e5f4ed,#eef8f1)}.nucleus{width:90px;height:90px;border-radius:50%;display:grid;place-content:center;text-align:center;background:#f6d46c;border:3px solid #c79b3b;font-weight:bold;line-height:1.5}.electron-label{position:absolute;right:0;top:10px;background:#cee9ec;border-radius:100px;padding:8px}.discovery-fields{display:grid;grid-template-columns:repeat(auto-fit,minmax(130px,1fr));gap:13px;margin:16px 0}.discovery-fields label{font-weight:bold;font-size:14px}.discovery-fields input{margin-top:7px}.separation-visual{display:grid;place-content:center;min-height:125px;background:#e7f3e9;border-radius:15px;font-size:44px;margin:18px 0}.rate-meter{text-align:center;background:#e6f3ed;border-radius:14px;padding:18px;margin:15px 0}.rate-meter strong{display:block;font-size:31px;color:#14353b}.rate-meter span{font-size:13px}.rate-bar{height:11px;background:#cbded6;border-radius:9px;overflow:hidden;margin:10px}.rate-bar div{height:100%;background:#126b62}.chromatography-paper{position:relative;width:min(100%,185px);height:220px;background:#fff9eb;border:3px solid #ddceb3;margin:22px auto;border-radius:6px}.chromatography-line{position:absolute;left:5px;right:5px;border-bottom:2px dashed #168199;text-align:center;color:#14677d;font-size:12px}.chromatography-spot{position:absolute;left:45%;color:#ad4b7f;font-size:27px}.chromatography-base{position:absolute;bottom:10px;left:7px;right:7px;text-align:center;border-top:1px solid #96856e;font-size:11px}.discovery-side-art{text-align:center;background:#e6f3ed;padding:12px;border-radius:18px;font-size:42px;margin-bottom:20px}
@media(max-width:750px){.discovery-fields{grid-template-columns:repeat(2,minmax(0,1fr))}.atom-ball{width:38px;height:38px}.atom-adjust{gap:3px;padding:5px}.atom-adjust button{min-width:41px}}