:root{
  --bg:#f3fbf7;--bg2:#eaf8f1;--panel:#ffffff;--panel-glass:rgba(255,255,255,.89);--panel-soft:#edf9f3;
  --text:#18352d;--muted:#647a72;--primary:#0f9f6e;--primary2:#06b6d4;--pink:#ec4899;--green:#22c55e;
  --yellow:#f59e0b;--red:#ef4444;--purple:#8b5cf6;--line:rgba(24,53,45,.12);--line-strong:rgba(15,159,110,.27);
  --shadow:0 22px 65px rgba(45,71,110,.13);--shadow-sm:0 9px 28px rgba(45,71,110,.10);
  --canvas:#f8fdfb;--grid:rgba(15,159,110,.065);--topbar:rgba(255,255,255,.86);
}
[data-theme="dark"]{
  --bg:#06140f;--bg2:#09231a;--panel:#0c211a;--panel-glass:rgba(12,33,26,.9);--panel-soft:#113126;
  --text:#effff8;--muted:#a3c2b5;--primary:#34d399;--primary2:#22d3ee;--pink:#f472b6;--green:#4ade80;
  --yellow:#fbbf24;--red:#fb7185;--purple:#c084fc;--line:rgba(255,255,255,.105);--line-strong:rgba(52,211,153,.34);
  --shadow:0 24px 70px rgba(0,0,0,.38);--shadow-sm:0 10px 30px rgba(0,0,0,.27);
  --canvas:#071a14;--grid:rgba(52,211,153,.07);--topbar:rgba(7,24,18,.86);
}
[hidden]{display:none!important}*{box-sizing:border-box}html{scroll-behavior:smooth}body{margin:0;min-height:100vh;overflow-x:hidden;color:var(--text);font-family:Inter,ui-sans-serif,system-ui,-apple-system,BlinkMacSystemFont,"Segoe UI",sans-serif;background:radial-gradient(circle at 10% 0%,color-mix(in srgb,var(--primary) 14%,transparent),transparent 27%),radial-gradient(circle at 92% 8%,color-mix(in srgb,var(--primary2) 13%,transparent),transparent 26%),linear-gradient(155deg,var(--bg),var(--bg2) 48%,var(--bg));transition:background .25s,color .25s}body.reduce-motion *,body.reduce-motion *::before,body.reduce-motion *::after{animation-duration:.001ms!important;animation-iteration-count:1!important;scroll-behavior:auto!important;transition-duration:.001ms!important}button,input,select{font:inherit}button{cursor:pointer}a{color:inherit}button:focus-visible,input:focus-visible,select:focus-visible,a:focus-visible{outline:3px solid color-mix(in srgb,var(--primary) 52%,transparent);outline-offset:2px}.shell{width:min(1320px,calc(100% - 28px));margin:0 auto;padding:20px 0 72px}.topbar-wrap{position:sticky;top:0;z-index:80;padding:10px 14px 0;pointer-events:none}.topbar{width:min(1320px,100%);margin:0 auto;display:flex;align-items:center;justify-content:space-between;gap:16px;padding:11px 13px;border:1px solid var(--line);border-radius:20px;background:var(--topbar);backdrop-filter:blur(18px);box-shadow:var(--shadow-sm);pointer-events:auto}.brand{display:flex;align-items:center;gap:11px;text-decoration:none;min-width:205px}.brand-mark{width:43px;height:43px;border-radius:14px;display:grid;place-items:center;color:#fff;font-weight:950;background:linear-gradient(135deg,var(--primary),var(--primary2));box-shadow:0 9px 24px color-mix(in srgb,var(--primary) 28%,transparent)}.brand strong{display:block;font-size:1.03rem}.brand small{display:block;color:var(--muted);font-size:.72rem;margin-top:2px}.nav-links{display:flex;align-items:center;justify-content:center;gap:4px;flex-wrap:wrap}.nav-links a{text-decoration:none;color:var(--muted);font-size:.81rem;font-weight:750;padding:8px 9px;border-radius:10px}.nav-links a:hover{color:var(--text);background:var(--panel-soft)}.top-actions{display:flex;align-items:center;justify-content:flex-end;gap:7px}.xp-pill,.level-pill{border:1px solid var(--line);background:var(--panel-soft);padding:8px 10px;border-radius:999px;font-size:.78rem;white-space:nowrap}.icon-btn{width:39px;height:39px;border:1px solid var(--line);border-radius:12px;display:grid;place-items:center;color:var(--text);background:var(--panel-soft);transition:.18s}.icon-btn:hover{transform:translateY(-2px);border-color:var(--line-strong)}.hero{display:grid;grid-template-columns:1.12fr .88fr;align-items:center;gap:34px;padding:68px 12px 38px}.eyebrow{display:inline-block;color:var(--primary);font-size:.77rem;font-weight:900;letter-spacing:.14em;text-transform:uppercase}.hero h1{margin:13px 0 18px;font-size:clamp(2.7rem,6vw,5.8rem);line-height:.94;letter-spacing:-.06em;max-width:810px}.hero h1 span{background:linear-gradient(90deg,var(--primary),var(--primary2),var(--pink));-webkit-background-clip:text;background-clip:text;color:transparent}.hero-copy>p{margin:0;color:var(--muted);font-size:1.08rem;line-height:1.76;max-width:760px}.hero-actions{display:flex;gap:11px;flex-wrap:wrap;margin-top:25px}.btn{border:1px solid var(--line);border-radius:13px;padding:11px 15px;color:var(--text);background:var(--panel);font-weight:850;transition:.18s;text-decoration:none;display:inline-flex;align-items:center;justify-content:center;gap:7px}.btn:hover{transform:translateY(-2px);box-shadow:var(--shadow-sm)}.btn.primary{color:#fff;border-color:transparent;background:linear-gradient(135deg,var(--primary),var(--primary2))}.btn.secondary{background:var(--panel-soft)}.btn.cheerful{color:#fff;border:0;background:linear-gradient(135deg,var(--pink),var(--purple))}.btn.danger{color:var(--red);background:color-mix(in srgb,var(--red) 8%,var(--panel));border-color:color-mix(in srgb,var(--red) 25%,var(--line))}.btn.tiny{padding:7px 10px;font-size:.76rem;border-radius:10px}.btn.full{width:100%}.daily-challenge{margin-top:24px;display:grid;grid-template-columns:auto 1fr auto;gap:11px;align-items:center;max-width:660px;padding:12px 13px;border:1px solid color-mix(in srgb,var(--yellow) 32%,var(--line));border-radius:15px;background:color-mix(in srgb,var(--yellow) 8%,var(--panel-glass));box-shadow:var(--shadow-sm)}.daily-icon{width:39px;height:39px;border-radius:12px;display:grid;place-items:center;background:color-mix(in srgb,var(--yellow) 17%,var(--panel))}.daily-challenge small{display:block;color:var(--muted);font-size:.7rem;text-transform:uppercase;letter-spacing:.08em}.daily-challenge strong{display:block;margin-top:3px;font-size:.9rem}.hero-world{min-height:365px;position:relative;display:grid;place-items:center;overflow:hidden}.hero-planet{width:112px;height:112px;border-radius:50%;display:grid;place-items:center;background:radial-gradient(circle at 32% 26%,#dffaff,var(--primary2) 28%,var(--primary) 64%,#312e81);box-shadow:0 0 75px color-mix(in srgb,var(--primary) 44%,transparent);z-index:3}.planet-face{font-size:2.1rem;color:#fff;transform:rotate(3deg)}.hero-orbit{position:absolute;border:1px solid color-mix(in srgb,var(--primary) 27%,transparent);border-radius:50%;transform:rotate(var(--r));animation:orbit var(--s) linear infinite}.hero-orbit span{position:absolute;width:17px;height:17px;border-radius:50%;left:-8px;top:calc(50% - 8px);background:var(--yellow);box-shadow:0 0 20px color-mix(in srgb,var(--yellow) 62%,transparent)}.orbit-a{width:285px;height:124px;--r:12deg;--s:8s}.orbit-b{width:350px;height:150px;--r:72deg;--s:12s}.orbit-c{width:240px;height:105px;--r:137deg;--s:6.5s}@keyframes orbit{to{transform:rotate(calc(var(--r) + 360deg))}}.hero-rocket{position:absolute;right:10%;bottom:13%;font-size:2.4rem;animation:rocketBob 3s ease-in-out infinite}@keyframes rocketBob{50%{transform:translate(-8px,-14px) rotate(-7deg)}}.formula-chip{position:absolute;z-index:4;padding:8px 11px;border:1px solid var(--line);border-radius:12px;background:var(--panel-glass);box-shadow:var(--shadow-sm);color:var(--primary);font-family:ui-monospace,SFMono-Regular,Menlo,monospace;font-weight:800;animation:floatChip 3.2s ease-in-out infinite}.chip-one{top:28px;left:10px}.chip-two{top:92px;right:10px;animation-delay:.5s}.chip-three{bottom:35px;left:42px;animation-delay:1s}.chip-four{right:52px;bottom:70px;animation-delay:1.5s}@keyframes floatChip{50%{transform:translateY(-7px)}}.progress-strip{display:grid;grid-template-columns:repeat(5,1fr);gap:11px;margin:5px 0 24px}.progress-strip article{padding:15px;border:1px solid var(--line);border-radius:17px;background:var(--panel-glass);box-shadow:var(--shadow-sm)}.progress-strip span{display:block;color:var(--muted);font-size:.72rem}.progress-strip strong{display:block;font-size:1.5rem;margin:4px 0}.progress-strip small{display:block;color:var(--muted);font-size:.72rem}.card,.card-soft{border:1px solid var(--line);background:var(--panel-glass);box-shadow:var(--shadow);border-radius:22px}.card-soft{box-shadow:var(--shadow-sm)}.mascot-tip{display:grid;grid-template-columns:auto 1fr auto;align-items:center;gap:13px;padding:12px 14px}.mascot{width:51px;height:51px;border-radius:50%;display:grid;place-items:center;background:radial-gradient(circle at 35% 28%,#fff,var(--yellow) 35%,#f97316);box-shadow:0 0 30px color-mix(in srgb,var(--yellow) 40%,transparent);font-weight:900;color:#713f12}.mascot-tip small{color:var(--primary);font-weight:850}.mascot-tip p{margin:3px 0 0;color:var(--muted);line-height:1.5}.section{margin-top:34px;scroll-margin-top:92px}.section-heading{display:flex;justify-content:space-between;align-items:flex-end;gap:18px;margin-bottom:16px;padding:0 2px}.section-heading h2{margin:6px 0 0;font-size:clamp(1.75rem,3vw,2.45rem);letter-spacing:-.035em}.section-heading h3{margin:0}.section-heading p{margin:7px 0 0;color:var(--muted);line-height:1.58;max-width:840px}.section-heading.compact{margin-top:26px}.section-actions{display:flex;gap:8px;flex-wrap:wrap}.confidence-key{display:flex;gap:7px;flex-wrap:wrap}.confidence{display:inline-flex;align-items:center;gap:5px;padding:6px 9px;border-radius:999px;border:1px solid var(--line);font-size:.71rem;font-weight:850;white-space:nowrap}.confidence.verified{color:var(--green);background:color-mix(in srgb,var(--green) 7%,var(--panel));border-color:color-mix(in srgb,var(--green) 30%,var(--line))}.confidence.simplified{color:var(--yellow);background:color-mix(in srgb,var(--yellow) 8%,var(--panel));border-color:color-mix(in srgb,var(--yellow) 31%,var(--line))}.confidence.theoretical{color:var(--purple);background:color-mix(in srgb,var(--purple) 8%,var(--panel));border-color:color-mix(in srgb,var(--purple) 31%,var(--line))}.lab-app{display:grid;grid-template-columns:300px 1fr;gap:17px;align-items:start}.lab-browser{position:sticky;top:85px;max-height:calc(100vh - 102px);overflow:hidden}.lab-browser-head{padding:13px;border-bottom:1px solid var(--line)}.search-box{display:flex;align-items:center;gap:8px;padding:10px 11px;border:1px solid var(--line);border-radius:12px;background:var(--panel-soft)}.search-box span{color:var(--muted);font-size:1.15rem}.search-box input{min-width:0;width:100%;border:0;outline:0;background:transparent;color:var(--text)}.search-box.large{min-width:min(470px,100%)}.lab-filter-row,.theory-filters{display:flex;gap:6px;flex-wrap:wrap;margin-top:10px}.filter-chip{border:1px solid var(--line);border-radius:999px;padding:6px 8px;background:var(--panel);color:var(--muted);font-size:.68rem;font-weight:750}.filter-chip.active{color:#fff;background:var(--primary);border-color:transparent}.lab-list{padding:9px;overflow:auto;max-height:calc(100vh - 207px)}.lab-item{width:100%;display:grid;grid-template-columns:38px 1fr auto;gap:9px;align-items:center;border:0;border-radius:13px;padding:9px;text-align:left;color:var(--text);background:transparent;margin-bottom:3px}.lab-item:hover{background:var(--panel-soft)}.lab-item.active{background:color-mix(in srgb,var(--primary) 10%,var(--panel));box-shadow:inset 0 0 0 1px color-mix(in srgb,var(--primary) 28%,transparent)}.lab-item-icon{width:36px;height:36px;border-radius:11px;display:grid;place-items:center;background:var(--panel-soft)}.lab-item.active .lab-item-icon{color:#fff;background:linear-gradient(135deg,var(--primary),var(--primary2))}.lab-item strong{display:block;font-size:.81rem}.lab-item small{display:block;color:var(--muted);font-size:.65rem;margin-top:2px}.lab-item-fav{color:var(--pink)}.workspace{overflow:hidden}.workspace-head{padding:17px 18px;display:flex;justify-content:space-between;gap:13px;border-bottom:1px solid var(--line);background:linear-gradient(120deg,color-mix(in srgb,var(--primary) 7%,var(--panel)),color-mix(in srgb,var(--primary2) 5%,var(--panel)))}.workspace-title-wrap{display:flex;gap:12px;align-items:flex-start}.workspace-icon{width:51px;height:51px;flex:0 0 auto;border-radius:15px;display:grid;place-items:center;font-size:1.45rem;color:#fff;background:linear-gradient(135deg,var(--primary),var(--primary2));box-shadow:0 9px 24px color-mix(in srgb,var(--primary) 23%,transparent)}.workspace-meta{display:flex;gap:8px;flex-wrap:wrap;color:var(--muted);font-size:.67rem;text-transform:uppercase;letter-spacing:.08em;font-weight:850}.workspace-meta span+span::before{content:"•";margin-right:8px}.workspace-head h3{margin:4px 0 4px;font-size:1.35rem}.workspace-head p{margin:0;color:var(--muted);line-height:1.45}.workspace-badges{display:flex;gap:7px;align-items:flex-start}.experiment-guide{display:flex;align-items:center;justify-content:center;gap:9px;padding:10px 18px;border-bottom:1px solid var(--line);background:var(--panel-soft);color:var(--muted);font-size:.72rem;font-weight:800}.experiment-guide span{display:flex;align-items:center;gap:5px}.experiment-guide b{width:22px;height:22px;border-radius:50%;display:grid;place-items:center;color:#fff;background:var(--primary)}.experiment-guide i{width:30px;height:2px;background:var(--line-strong)}.workspace-grid{display:grid;grid-template-columns:285px 1fr;gap:14px;padding:16px}.control-panel{border:1px solid var(--line);border-radius:16px;padding:13px;background:var(--panel)}.panel-title{display:flex;align-items:center;justify-content:space-between;gap:8px;margin-bottom:12px}.text-btn{border:0;background:transparent;color:var(--primary);font-size:.73rem;font-weight:850}.control-group{margin-bottom:13px}.control-label{display:flex;justify-content:space-between;gap:8px;margin-bottom:7px;font-size:.76rem}.control-label span{color:var(--muted)}.control-label strong{color:var(--primary);text-align:right}.control-group input[type="range"]{width:100%;accent-color:var(--primary)}.control-group select,.speed-select select{width:100%;border:1px solid var(--line);border-radius:10px;padding:9px;color:var(--text);background:var(--panel-soft)}.check-control{display:flex;align-items:center;gap:9px;padding:9px;border:1px solid var(--line);border-radius:11px;background:var(--panel-soft);font-size:.78rem}.check-control 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var(--line);border-radius:10px;display:grid;place-items:center;color:var(--text);background:var(--panel-glass);backdrop-filter:blur(10px);font-size:1rem}.canvas-shell:fullscreen{width:100vw;height:100vh;border:0;border-radius:0;display:grid;place-items:center;background:var(--canvas)}.canvas-shell:fullscreen #labCanvas{width:min(100vw,187.5vh);height:auto}.canvas-shell:fullscreen .canvas-hint{bottom:18px;right:18px}.canvas-shell:fullscreen .canvas-status{left:18px;top:18px}.canvas-shell:fullscreen .canvas-fullscreen{right:18px;top:18px}.canvas-hint{position:absolute;right:10px;bottom:9px;color:var(--muted);font-size:.64rem;background:var(--panel-glass);padding:5px 7px;border-radius:8px}.readout-grid{display:grid;grid-template-columns:repeat(4,1fr);gap:7px;margin-top:8px}.readout{padding:9px 10px;border:1px solid var(--line);border-radius:11px;background:var(--panel-soft);min-width:0}.readout span{display:block;color:var(--muted);font-size:.64rem}.readout 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8px;border-radius:9px;background:var(--panel-soft);overflow:hidden;text-overflow:ellipsis;white-space:nowrap}.topic-card .btn{align-self:flex-start;padding:7px 9px;font-size:.7rem}.tools-grid{display:grid;grid-template-columns:1.35fr .65fr;gap:14px}.formula-lab,.unit-tool{padding:16px}.tool-head{display:flex;justify-content:space-between;align-items:flex-start;gap:12px;margin-bottom:14px}.tool-head small{color:var(--primary);font-weight:850;text-transform:uppercase;letter-spacing:.08em}.tool-head h3{margin:4px 0 0}.tool-icon{width:43px;height:43px;border-radius:13px;display:grid;place-items:center;color:#fff;background:linear-gradient(135deg,var(--primary),var(--primary2));font-size:1.3rem;font-weight:900}.formula-layout{display:grid;grid-template-columns:230px 1fr;gap:12px}.formula-menu{display:grid;gap:5px;max-height:490px;overflow:auto;padding-right:4px}.formula-menu-btn{border:1px solid var(--line);border-radius:10px;padding:8px 9px;text-align:left;color:var(--text);background:var(--panel);font-size:.72rem}.formula-menu-btn small{display:block;color:var(--muted);margin-top:2px}.formula-menu-btn.active{border-color:var(--primary);background:color-mix(in srgb,var(--primary) 9%,var(--panel))}.formula-workbench{padding:13px;border:1px solid var(--line);border-radius:14px;background:var(--panel-soft)}.formula-display{padding:13px;border-radius:12px;background:var(--panel);border:1px solid var(--line);color:var(--primary);font-size:1.25rem;font-family:ui-monospace,monospace;font-weight:850}.formula-workbench>p{color:var(--muted);font-size:.81rem;line-height:1.5}.formula-inputs{display:grid;grid-template-columns:repeat(2,1fr);gap:8px;margin:12px 0}.formula-inputs label,.unit-tool label{display:grid;gap:5px;color:var(--muted);font-size:.71rem}.formula-inputs input,.unit-tool input,.unit-tool select{width:100%;border:1px solid var(--line);border-radius:10px;padding:9px;color:var(--text);background:var(--panel)}.formula-answer{margin-top:10px;padding:12px;border:1px solid color-mix(in srgb,var(--green) 28%,var(--line));border-radius:12px;background:color-mix(in srgb,var(--green) 7%,var(--panel))}.formula-answer small{color:var(--muted)}.formula-answer strong{display:block;font-size:1.35rem;margin-top:4px}.formula-answer p{margin:5px 0 0;color:var(--muted);font-size:.75rem;line-height:1.45}.unit-tool>label{margin-bottom:11px}.converter-row{display:grid;grid-template-columns:1fr 1fr;gap:8px}.swap-btn{display:block;width:38px;height:38px;margin:10px auto;border:1px solid var(--line);border-radius:50%;background:var(--panel-soft);color:var(--primary);font-weight:900}.unit-note{margin-top:14px;padding:11px;border:1px solid var(--line);border-radius:11px;background:var(--panel-soft);color:var(--muted);font-size:.77rem;line-height:1.45}.mission-progress{display:grid;grid-template-columns:auto 1fr;align-items:center;gap:20px;padding:14px 16px;margin-bottom:13px}.mission-progress strong{display:block}.mission-progress span{display:block;color:var(--muted);font-size:.75rem;margin-top:3px}.progress-track{height:10px;border-radius:99px;background:var(--panel-soft);overflow:hidden;border:1px solid var(--line)}.progress-track div{height:100%;width:0;background:linear-gradient(90deg,var(--primary),var(--primary2),var(--green));transition:width .35s}.mission-grid{display:grid;grid-template-columns:repeat(4,1fr);gap:10px}.arcade-card{border:1px solid var(--line);border-radius:16px;padding:13px;background:var(--panel-glass);box-shadow:var(--shadow-sm)}.arcade-card.complete{border-color:color-mix(in srgb,var(--green) 43%,var(--line));background:color-mix(in srgb,var(--green) 6%,var(--panel-glass))}.arcade-card-top{display:flex;justify-content:space-between;gap:8px}.arcade-card-icon{width:39px;height:39px;border-radius:12px;display:grid;place-items:center;background:var(--panel-soft)}.arcade-card h3{font-size:.91rem;margin:9px 0 6px}.arcade-card p{margin:0;color:var(--muted);font-size:.73rem;line-height:1.45;min-height:52px}.arcade-card-bottom{display:flex;justify-content:space-between;align-items:center;gap:8px;margin-top:10px}.reward{color:var(--yellow);font-size:.7rem;font-weight:900}.achievement-grid{display:grid;grid-template-columns:repeat(7,1fr);gap:9px}.achievement{padding:12px 9px;text-align:center;border:1px solid var(--line);border-radius:15px;background:var(--panel-glass);filter:grayscale(1);opacity:.55}.achievement.unlocked{filter:none;opacity:1;border-color:color-mix(in srgb,var(--yellow) 38%,var(--line));box-shadow:0 10px 25px color-mix(in srgb,var(--yellow) 12%,transparent)}.achievement-icon{font-size:1.7rem}.achievement strong{display:block;font-size:.73rem;margin-top:6px}.achievement small{display:block;color:var(--muted);font-size:.61rem;margin-top:3px;line-height:1.3}.quiz-section{display:grid;grid-template-columns:.7fr 1.3fr;overflow:hidden}.quiz-intro{padding:23px;background:linear-gradient(145deg,color-mix(in srgb,var(--primary) 15%,var(--panel)),color-mix(in srgb,var(--primary2) 11%,var(--panel)))}.quiz-intro h2{margin:8px 0 10px}.quiz-intro p{color:var(--muted);line-height:1.58}.quiz-stats{display:flex;gap:8px;flex-wrap:wrap;margin:16px 0}.quiz-stats span{padding:8px 10px;border:1px solid var(--line);border-radius:999px;background:var(--panel-glass);font-size:.72rem}.quiz-player{padding:23px}.quiz-progress{height:9px;border-radius:99px;background:var(--panel-soft);overflow:hidden}.quiz-progress div{height:100%;width:0;background:linear-gradient(90deg,var(--primary),var(--primary2));transition:width .3s}.quiz-player>small{display:block;color:var(--muted);margin-top:8px}.quiz-player h3{line-height:1.45;min-height:50px}.quiz-options{display:grid;gap:8px}.quiz-option{border:1px solid var(--line);border-radius:12px;padding:11px 12px;text-align:left;color:var(--text);background:var(--panel);font-weight:700}.quiz-option:hover{border-color:var(--primary)}.quiz-option.correct{border-color:var(--green);background:color-mix(in srgb,var(--green) 9%,var(--panel))}.quiz-option.wrong{border-color:var(--red);background:color-mix(in srgb,var(--red) 8%,var(--panel))}.quiz-feedback{min-height:48px;color:var(--muted);line-height:1.48}.notebook-list{display:grid;gap:9px}.note-card{display:grid;grid-template-columns:auto 1fr auto;gap:12px;align-items:center;padding:12px;border:1px solid var(--line);border-radius:14px;background:var(--panel-glass);box-shadow:var(--shadow-sm)}.note-number{width:39px;height:39px;border-radius:12px;display:grid;place-items:center;color:#fff;background:linear-gradient(135deg,var(--primary),var(--primary2));font-weight:900}.note-card h3{margin:0;font-size:.9rem}.note-card p{margin:4px 0;color:var(--muted);font-size:.74rem;line-height:1.42}.note-card small{color:var(--muted);font-size:.65rem}.empty-state{padding:28px;text-align:center;border:1px dashed var(--line-strong);border-radius:17px;color:var(--muted);background:var(--panel-soft)}.footer{width:min(1320px,calc(100% - 28px));margin:0 auto 28px;padding:22px;display:grid;grid-template-columns:auto 1fr 1fr;gap:20px;align-items:center;border:1px solid var(--line);border-radius:20px;background:var(--panel-glass);box-shadow:var(--shadow-sm);color:var(--muted);font-size:.8rem}.footer-logo{display:flex;align-items:center;gap:10px}.footer-logo strong{display:block;color:var(--text)}.footer-logo small{display:block}.footer p{margin:0;text-align:center;line-height:1.65}.footer a{color:var(--primary);font-weight:900}.topic-dialog{width:min(780px,calc(100% - 28px));max-height:88vh;overflow:auto;border:1px solid var(--line);border-radius:22px;padding:22px;background:var(--panel);color:var(--text);box-shadow:var(--shadow)}.topic-dialog::backdrop{background:rgba(3,8,18,.74);backdrop-filter:blur(7px)}.dialog-close{position:sticky;float:right;top:0;width:38px;height:38px;border:1px solid var(--line);border-radius:11px;background:var(--panel-soft);color:var(--text)}.topic-dialog h2{margin:10px 0 7px}.dialog-lead{color:var(--muted);font-size:1rem;line-height:1.65}.dialog-formula{padding:12px 13px;border:1px solid var(--line);border-radius:12px;background:var(--panel-soft);color:var(--primary);font-family:ui-monospace,monospace;font-weight:800}.dialog-sections{display:grid;grid-template-columns:1fr 1fr;gap:10px;margin:13px 0}.dialog-section{padding:12px;border:1px solid var(--line);border-radius:12px;background:var(--panel-soft)}.dialog-section h3{font-size:.84rem;margin:0 0 5px}.dialog-section p{margin:0;color:var(--muted);line-height:1.52;font-size:.78rem}.toast{position:fixed;left:50%;bottom:24px;z-index:120;transform:translate(-50%,25px);opacity:0;pointer-events:none;padding:11px 15px;border:1px solid var(--line);border-radius:999px;background:var(--panel);color:var(--text);box-shadow:var(--shadow);font-size:.8rem;font-weight:800;transition:.22s}.toast.show{transform:translate(-50%,0);opacity:1}#confettiLayer{position:fixed;inset:0;z-index:110;pointer-events:none;overflow:hidden}.confetti{position:absolute;top:-20px;width:10px;height:16px;border-radius:3px;animation:confettiFall var(--duration) linear forwards}@keyframes confettiFall{to{transform:translate(var(--drift),110vh) rotate(900deg);opacity:.9}}
@media(max-width:1150px){.nav-links{display:none}.progress-strip{grid-template-columns:repeat(3,1fr)}.topic-grid{grid-template-columns:repeat(3,1fr)}.mission-grid{grid-template-columns:repeat(3,1fr)}.achievement-grid{grid-template-columns:repeat(4,1fr)}.lab-app{grid-template-columns:250px 1fr}.workspace-grid{grid-template-columns:250px 1fr}.readout-grid{grid-template-columns:repeat(2,1fr)}}
@media(max-width:900px){.hero{grid-template-columns:1fr}.hero-world{min-height:300px}.lab-app{grid-template-columns:1fr}.lab-browser{position:static;max-height:none}.lab-list{display:grid;grid-template-columns:repeat(2,1fr);max-height:340px}.workspace-grid,.tools-grid{grid-template-columns:1fr}.control-panel{display:grid;grid-template-columns:repeat(2,1fr);gap:10px}.control-panel>.panel-title,.control-panel>.simulation-actions,.control-panel>#specialActionBtn{grid-column:1/-1}.control-group{margin:0}.formula-layout{grid-template-columns:190px 1fr}.topic-grid{grid-template-columns:repeat(2,1fr)}.mission-grid{grid-template-columns:repeat(2,1fr)}.quiz-section{grid-template-columns:1fr}.footer{grid-template-columns:1fr;text-align:center}.footer-logo{justify-content:center}}
@media(max-width:620px){.topbar-wrap{position:static}.topbar{align-items:flex-start}.brand{min-width:0}.xp-pill,.level-pill{display:none}.shell{width:min(calc(100% - 18px),1320px)}.hero{padding:42px 5px 24px}.hero h1{font-size:clamp(2.35rem,13vw,4rem)}.daily-challenge{grid-template-columns:auto 1fr}.daily-challenge .btn{grid-column:1/-1}.progress-strip{grid-template-columns:repeat(2,1fr)}.mascot-tip{grid-template-columns:auto 1fr}.mascot-tip .icon-btn{grid-column:1/-1;width:100%}.section-heading{align-items:flex-start;flex-direction:column}.confidence-key{justify-content:flex-start}.lab-list{grid-template-columns:1fr}.workspace-head{align-items:flex-start;flex-direction:column}.experiment-guide{gap:4px;overflow:auto;justify-content:flex-start}.experiment-guide i{width:14px}.workspace-grid{padding:10px}.control-panel{grid-template-columns:1fr}.learning-grid{grid-template-columns:1fr;padding:0 10px 10px}.explanation-tabs{padding-left:10px;padding-right:10px}.explanation-panel{margin-left:10px;margin-right:10px}.workspace-footer-actions{padding-left:10px;padding-right:10px}.theory-tools{align-items:stretch;flex-direction:column}.search-box.large{min-width:0}.theory-filters{justify-content:flex-start}.topic-grid,.mission-grid{grid-template-columns:1fr}.formula-layout{grid-template-columns:1fr}.formula-menu{grid-template-columns:repeat(2,1fr);max-height:260px}.formula-inputs{grid-template-columns:1fr}.achievement-grid{grid-template-columns:repeat(2,1fr)}.mission-progress{grid-template-columns:1fr}.dialog-sections{grid-template-columns:1fr}.note-card{grid-template-columns:auto 1fr}.note-card .btn{grid-column:1/-1}.hero-world{min-height:265px}.formula-chip{font-size:.68rem}.progress-strip article:last-child{grid-column:1/-1}}



/* Element Forge colour system and chemistry-specific components */
:root{
  --bg:#f4f8ff;--bg2:#eaf3ff;--panel:#ffffff;--panel-glass:rgba(255,255,255,.9);--panel-soft:#edf4ff;
  --text:#172b45;--muted:#66778d;--primary:#2563eb;--primary2:#06b6d4;--pink:#8b5cf6;--green:#10b981;
  --yellow:#f59e0b;--red:#ef4444;--purple:#7c3aed;--line:rgba(23,43,69,.12);--line-strong:rgba(37,99,235,.29);
  --shadow:0 22px 65px rgba(45,71,110,.13);--shadow-sm:0 9px 28px rgba(45,71,110,.10);
  --canvas:#f8fbff;--grid:rgba(37,99,235,.065);--topbar:rgba(255,255,255,.87);
  --alkali:#ffd0d5;--alkaline:#ffe0a8;--transition:#bfe1ff;--post:#c9ead9;--metalloid:#ded3ff;
  --nonmetal:#fff0a8;--halogen:#bcefe3;--noble:#cdd8ff;--lanthanide:#d9f5ca;--actinide:#f1cfea;
}
[data-theme="dark"]{
  --bg:#06101d;--bg2:#0a1a2c;--panel:#0c1b2d;--panel-glass:rgba(12,27,45,.91);--panel-soft:#102740;
  --text:#eff7ff;--muted:#a1b5ca;--primary:#60a5fa;--primary2:#22d3ee;--pink:#c084fc;--green:#34d399;
  --yellow:#fbbf24;--red:#fb7185;--purple:#a78bfa;--line:rgba(255,255,255,.105);--line-strong:rgba(96,165,250,.36);
  --shadow:0 24px 70px rgba(0,0,0,.38);--shadow-sm:0 10px 30px rgba(0,0,0,.27);
  --canvas:#071626;--grid:rgba(96,165,250,.07);--topbar:rgba(7,22,38,.87);
  --alkali:#69323a;--alkaline:#6c4d29;--transition:#244f73;--post:#285c49;--metalloid:#4e426d;
  --nonmetal:#655c2b;--halogen:#275e55;--noble:#354873;--lanthanide:#385f35;--actinide:#65415f;
}
.chem-world{min-height:390px}.atom-hero{position:relative;width:118px;height:118px;border-radius:50%;display:grid;place-items:center;background:radial-gradient(circle at 34% 28%,#fff,#79e0ff 20%,var(--primary) 55%,#312e81);box-shadow:0 0 80px color-mix(in srgb,var(--primary) 44%,transparent);z-index:3;color:#fff;font-weight:950;font-size:2rem;animation:atomPulse 3.2s ease-in-out infinite}.atom-hero small{display:block;font-size:.58rem;text-align:center;line-height:1.2}.chem-orbit{position:absolute;border:1.5px solid color-mix(in srgb,var(--primary) 28%,transparent);border-radius:50%;transform:rotate(var(--r));animation:orbit var(--s) linear infinite}.chem-orbit i{position:absolute;width:17px;height:17px;border-radius:50%;left:-8px;top:calc(50% - 8px);background:var(--yellow);box-shadow:0 0 20px color-mix(in srgb,var(--yellow) 65%,transparent)}.chem-orbit.a{width:290px;height:120px;--r:12deg;--s:8s}.chem-orbit.b{width:350px;height:150px;--r:72deg;--s:11s}.chem-orbit.c{width:245px;height:102px;--r:136deg;--s:6.5s}.chem-flask-float{position:absolute;right:8%;bottom:11%;font-size:2.8rem;animation:rocketBob 3s ease-in-out infinite}.chem-mascot{background:radial-gradient(circle at 35% 28%,#fff,#60a5fa 34%,#1d4ed8);color:#172554}.chem-mascot::after{content:"⚛";font-size:1.25rem;color:#fff}
@keyframes atomPulse{50%{transform:scale(1.04);filter:saturate(1.15)}}

/* Interactive periodic table */
.periodic-toolbar{display:flex;gap:10px;flex-wrap:wrap;align-items:center;padding:13px}.periodic-toolbar .search-box{min-width:min(360px,100%);flex:1}.periodic-actions{display:flex;gap:7px;flex-wrap:wrap}.periodic-shell{padding:14px;overflow:hidden}.periodic-scroll{overflow-x:auto;padding:3px 1px 12px}.periodic-grid{min-width:1110px;display:grid;grid-template-columns:repeat(18,minmax(50px,1fr));grid-template-rows:repeat(10,80px);gap:5px}.element-tile{position:relative;min-width:0;border:1px solid color-mix(in srgb,var(--text) 20%,transparent);border-radius:10px;padding:5px;text-align:left;color:var(--text);background:var(--panel);overflow:hidden;transition:.16s;box-shadow:none}.element-tile:hover{transform:translateY(-3px) scale(1.02);z-index:5;box-shadow:var(--shadow-sm);border-color:var(--line-strong)}.element-tile.selected{outline:3px solid var(--primary);outline-offset:1px}.element-tile.compare{box-shadow:inset 0 0 0 3px var(--purple)}.element-tile.dim{opacity:.16;filter:grayscale(.8)}.element-tile .atomic{font-size:.61rem;opacity:.82}.element-tile .symbol{font-size:1.23rem;font-weight:950;line-height:1.05}.element-tile .ename{font-size:.57rem;white-space:nowrap;overflow:hidden;text-overflow:ellipsis}.element-tile .mass{font-size:.52rem;color:var(--muted);margin-top:2px}.element-tile .hazard-dot{position:absolute;right:4px;top:3px;font-size:.57rem}.element-tile .trend-value{position:absolute;left:5px;right:5px;bottom:4px;font-size:.5rem;font-weight:850;white-space:nowrap;overflow:hidden;text-overflow:ellipsis}.periodic-placeholder{display:grid;place-items:center;border:1px dashed var(--line);border-radius:10px;color:var(--muted);font-size:.7rem;background:var(--panel-soft);text-align:center;padding:5px}.cat-Alkali-metal{background:var(--alkali)}.cat-Alkaline-earth-metal{background:var(--alkaline)}.cat-Transition-metal{background:var(--transition)}.cat-Post-transition-metal{background:var(--post)}.cat-Metalloid{background:var(--metalloid)}.cat-Reactive-non-metal,.cat-Nonmetal{background:var(--nonmetal)}.cat-Halogen{background:var(--halogen)}.cat-Noble-gas{background:var(--noble)}.cat-Lanthanide{background:var(--lanthanide)}.cat-Actinide{background:var(--actinide)}.periodic-legend{display:flex;gap:8px;flex-wrap:wrap;margin-top:10px}.periodic-legend button{display:flex;align-items:center;gap:6px;border:0;background:transparent;color:var(--muted);font-size:.71rem;padding:3px}.periodic-legend i{width:13px;height:13px;border:1px solid var(--line);border-radius:4px}.selection-tray{display:flex;gap:7px;flex-wrap:wrap;min-height:44px;padding:8px;border:1px dashed var(--line-strong);border-radius:13px;background:var(--panel-soft)}.selection-chip{display:flex;align-items:center;gap:7px;border:1px solid var(--line);border-radius:999px;padding:5px 7px 5px 10px;background:var(--panel);font-size:.75rem}.selection-chip strong{font-size:.88rem}.selection-chip button{width:23px;height:23px;border:0;border-radius:50%;background:var(--panel-soft);color:var(--text)}.selection-empty{color:var(--muted);font-size:.76rem;align-self:center}.quick-elements{display:grid;grid-template-columns:repeat(6,1fr);gap:5px;margin-top:8px}.quick-elements button{border:1px solid var(--line);border-radius:9px;padding:7px 4px;background:var(--panel);color:var(--text);font-weight:900;font-size:.72rem}.quick-elements button.active{color:#fff;background:var(--primary);border-color:transparent}.chem-warning{padding:10px 11px;margin-top:8px;border:1px solid color-mix(in srgb,var(--red) 29%,var(--line));border-radius:11px;background:color-mix(in srgb,var(--red) 6%,var(--panel));color:var(--muted);font-size:.71rem;line-height:1.45}.trend-key{display:flex;align-items:center;gap:8px;color:var(--muted);font-size:.7rem}.trend-gradient{width:130px;height:10px;border-radius:99px;background:linear-gradient(90deg,#dbeafe,#22d3ee,#2563eb,#7c3aed)}

.element-explorer-grid{display:grid;grid-template-columns:repeat(5,minmax(0,1fr));gap:10px}.element-profile-card{border:1px solid var(--line);border-radius:16px;padding:13px;background:var(--panel-glass);box-shadow:var(--shadow-sm);text-align:left;color:var(--text);transition:.17s;min-width:0}.element-profile-card:hover{transform:translateY(-3px);border-color:var(--line-strong)}.element-profile-card header{display:flex;align-items:start;justify-content:space-between;gap:9px}.element-profile-card .mini-symbol{width:48px;height:48px;border-radius:13px;display:grid;place-items:center;font-size:1.35rem;font-weight:950;background:linear-gradient(145deg,color-mix(in srgb,var(--primary) 14%,var(--panel)),color-mix(in srgb,var(--primary2) 13%,var(--panel)))}.element-profile-card strong{display:block;font-size:.86rem;margin-top:8px}.element-profile-card small{display:block;color:var(--muted);font-size:.67rem;margin-top:3px}.element-profile-card .element-facts-line{display:flex;gap:5px;flex-wrap:wrap;margin-top:8px}.compare-panel{display:grid;grid-template-columns:repeat(4,minmax(0,1fr));gap:9px;padding:14px}.compare-slot{border:1px solid var(--line);border-radius:14px;padding:12px;background:var(--panel-soft);min-height:120px}.compare-slot.empty{display:grid;place-items:center;color:var(--muted);font-size:.75rem;border-style:dashed}.compare-slot h4{margin:0 0 6px}.compare-slot dl{margin:0;display:grid;gap:4px}.compare-slot div{display:flex;justify-content:space-between;gap:8px;font-size:.7rem}.compare-slot dt{color:var(--muted)}.compare-slot dd{margin:0;font-weight:800;text-align:right}

/* Element detail dialog */
.element-dialog{width:min(980px,calc(100% - 24px));max-height:min(92vh,900px)}.element-dialog-head{display:grid;grid-template-columns:auto 1fr auto;gap:15px;align-items:center}.dialog-element-symbol{width:86px;height:86px;border-radius:21px;display:grid;place-items:center;color:#fff;background:linear-gradient(135deg,var(--primary),var(--primary2));font-size:2.2rem;font-weight:950;box-shadow:0 12px 30px color-mix(in srgb,var(--primary) 27%,transparent)}.dialog-element-title h2{margin:0}.dialog-element-title p{margin:5px 0 0;color:var(--muted)}.element-detail-grid{display:grid;grid-template-columns:repeat(4,minmax(0,1fr));gap:9px;margin-top:15px}.element-detail{border:1px solid var(--line);border-radius:13px;padding:11px;background:var(--panel-soft);min-width:0}.element-detail span{display:block;color:var(--muted);font-size:.67rem;margin-bottom:4px}.element-detail strong{display:block;font-size:.81rem;overflow-wrap:anywhere}.element-story-grid{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:10px;margin-top:13px}.element-story{border:1px solid var(--line);border-radius:14px;padding:13px;background:var(--panel-glass)}.element-story h3{margin:0 0 6px;font-size:.87rem}.element-story p{margin:0;color:var(--muted);font-size:.76rem;line-height:1.56}.shell-visual{display:flex;gap:7px;flex-wrap:wrap;margin-top:7px}.shell-pill{border:1px solid var(--line);border-radius:999px;padding:5px 8px;background:var(--panel);font-size:.7rem}.element-dialog-actions{display:flex;gap:8px;flex-wrap:wrap;margin-top:14px}

/* Lab-specific reaction outcome blocks */
.reaction-results{display:grid;gap:8px;margin-top:8px}.reaction-path{padding:10px;border:1px solid var(--line);border-radius:11px;background:var(--panel-soft)}.reaction-path header{display:flex;justify-content:space-between;gap:8px;align-items:start}.reaction-path h5{margin:0}.reaction-path .equation{font-family:ui-monospace,SFMono-Regular,Menlo,monospace;color:var(--primary);font-size:.7rem;margin:5px 0}.reaction-path p{margin:4px 0 0;color:var(--muted);font-size:.68rem;line-height:1.42}.outcome-tags{display:flex;gap:5px;flex-wrap:wrap;margin-top:5px}.outcome-tags span{border:1px solid var(--line);border-radius:999px;padding:4px 6px;font-size:.62rem;background:var(--panel)}.canvas-overlay-title{position:absolute;left:12px;top:11px;padding:7px 9px;border-radius:10px;background:var(--panel-glass);border:1px solid var(--line);font-size:.69rem;font-weight:850;pointer-events:none}.canvas-overlay-warning{position:absolute;right:12px;top:11px;padding:7px 9px;border-radius:10px;background:color-mix(in srgb,var(--red) 9%,var(--panel-glass));border:1px solid color-mix(in srgb,var(--red) 28%,var(--line));font-size:.66rem;color:var(--red);font-weight:850;pointer-events:none}.source-card{padding:16px;display:grid;grid-template-columns:auto 1fr;gap:12px;align-items:start}.source-card span{font-size:1.7rem}.source-card h3{margin:0 0 5px}.source-card p{margin:0;color:var(--muted);font-size:.78rem;line-height:1.55}.source-card a{color:var(--primary);font-weight:850}.source-grid{display:grid;grid-template-columns:repeat(3,1fr);gap:10px}

/* Chemistry glossary and long-content safeguards */
.glossary-grid{display:grid;grid-template-columns:repeat(4,minmax(0,1fr));gap:9px}.glossary-card{padding:13px;border:1px solid var(--line);border-radius:14px;background:var(--panel-glass);box-shadow:var(--shadow-sm);min-width:0}.glossary-card strong{display:block;color:var(--primary);font-size:.84rem}.glossary-card p{margin:5px 0 0;color:var(--muted);font-size:.71rem;line-height:1.46}.topic-grid{grid-template-columns:repeat(4,minmax(0,1fr));min-width:0}.topic-card{min-width:0;max-width:100%}.topic-formula{max-width:100%;overflow-wrap:anywhere}.formula-menu{scrollbar-width:thin}

@media(max-width:1180px){.element-explorer-grid{grid-template-columns:repeat(4,minmax(0,1fr))}.source-grid{grid-template-columns:1fr 1fr}.glossary-grid{grid-template-columns:repeat(3,minmax(0,1fr))}}
@media(max-width:900px){.element-explorer-grid{grid-template-columns:repeat(3,minmax(0,1fr))}.compare-panel{grid-template-columns:repeat(2,minmax(0,1fr))}.element-detail-grid{grid-template-columns:repeat(2,minmax(0,1fr))}.source-grid{grid-template-columns:1fr}.glossary-grid{grid-template-columns:repeat(2,minmax(0,1fr))}.quick-elements{grid-template-columns:repeat(4,1fr)}}
@media(max-width:620px){.chem-world{min-height:285px}.atom-hero{width:94px;height:94px;font-size:1.55rem}.chem-orbit.a{width:225px;height:95px}.chem-orbit.b{width:270px;height:113px}.chem-orbit.c{width:190px;height:80px}.element-explorer-grid,.glossary-grid{grid-template-columns:1fr}.compare-panel{grid-template-columns:1fr}.element-story-grid{grid-template-columns:1fr}.element-dialog-head{grid-template-columns:auto 1fr}.element-dialog-head .dialog-close{grid-column:1/-1;width:100%}.quick-elements{grid-template-columns:repeat(3,1fr)}.periodic-toolbar{align-items:stretch;flex-direction:column}}

/* Element Forge 2.0 interaction refinements */
.range-ends{display:flex;justify-content:space-between;color:var(--muted);font-size:.61rem;margin-top:3px}.segmented-control{display:grid;grid-template-columns:repeat(auto-fit,minmax(82px,1fr));gap:5px}.segmented-control button{border:1px solid var(--line);border-radius:9px;padding:8px 6px;background:var(--panel);color:var(--muted);font-size:.68rem;line-height:1.25;font-weight:750}.segmented-control button.active{background:linear-gradient(135deg,var(--primary),var(--primary2));border-color:transparent;color:#fff;box-shadow:0 6px 16px color-mix(in srgb,var(--primary) 22%,transparent)}.element-control select{margin-top:8px}.element-tile{padding:0}.element-tile .tile-main{position:absolute;inset:0;width:100%;height:100%;border:0;background:transparent;color:inherit;text-align:left;padding:5px;display:flex;flex-direction:column;align-items:flex-start}.element-tile .tile-info{position:absolute;right:4px;bottom:4px;z-index:4;width:18px;height:18px;border:1px solid color-mix(in srgb,var(--text) 25%,transparent);border-radius:50%;padding:0;display:grid;place-items:center;background:color-mix(in srgb,var(--panel) 88%,transparent);color:var(--text);font-size:.6rem;font-weight:950}.element-tile .tile-info:hover{background:var(--primary);color:#fff}.element-tile .hazard-dot{right:5px;top:4px}.element-tile .trend-value{right:24px}.series-slot{font-size:.58rem;line-height:1.2}.series-label{font-weight:900;color:var(--primary)}.element-profile-top{display:grid;grid-template-columns:auto 1fr;gap:10px;align-items:center}.profile-symbol{width:54px;height:54px;border:1px solid color-mix(in srgb,var(--text) 18%,transparent);border-radius:14px;display:grid;place-items:center;font-size:1.4rem;font-weight:950}.element-profile-top h3{margin:2px 0;font-size:1rem}.element-profile-top small,.element-profile-top span{color:var(--muted);font-size:.65rem}.element-profile-card>p{color:var(--muted);font-size:.74rem;line-height:1.5;min-height:66px;margin:10px 0}.element-profile-card .element-facts-line{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:5px}.element-profile-card .element-facts-line span{border:1px solid var(--line);border-radius:9px;padding:6px;background:var(--panel-soft);font-size:.58rem;color:var(--muted);min-width:0}.element-profile-card .element-facts-line strong{font-size:.64rem;white-space:nowrap;overflow:hidden;text-overflow:ellipsis}.profile-actions{display:flex;gap:6px;flex-wrap:wrap;margin-top:10px}.compare-slot{position:relative}.compare-slot .compare-remove{position:absolute;right:7px;top:7px;width:27px;height:27px;border:1px solid var(--line);border-radius:9px;background:var(--panel);color:var(--text)}.compare-slot h3{margin:8px 0 2px}.compare-slot>small{color:var(--muted);font-size:.68rem}.compare-slot dl{margin-top:10px}.compare-slot dl>div{display:flex;justify-content:space-between;gap:8px;font-size:.67rem;padding:4px 0;border-bottom:1px dashed var(--line)}.compare-slot dt{color:var(--muted)}.compare-slot dd{margin:0;text-align:right;font-weight:800}.compare-empty{grid-column:1/-1;display:grid;place-items:center;text-align:center;padding:26px;color:var(--muted)}.compare-empty span{font-size:2rem}.compare-empty strong{color:var(--text);margin-top:8px}.compare-empty p{margin:4px 0}.element-story{display:grid;grid-template-columns:auto 1fr;gap:10px}.element-story>span{font-size:1.25rem}.element-story h3{font-size:.83rem}.reaction-results{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:8px;margin-top:12px}.reaction-path{border:1px solid var(--line);border-radius:13px;padding:11px;background:var(--panel-soft);min-width:0}.reaction-path>div{display:flex;gap:5px;flex-wrap:wrap}.reaction-path h4{margin:8px 0 5px}.reaction-path code{display:block;color:var(--primary);font-size:.68rem;white-space:normal;overflow-wrap:anywhere}.reaction-path p{font-size:.7rem;color:var(--muted);line-height:1.45;margin:7px 0 0}.hazard-badge{display:inline-flex;padding:5px 8px;border-radius:999px;border:1px solid var(--line);font-size:.66rem;font-weight:850}.hazard-badge.hazard-extreme{color:var(--red);border-color:color-mix(in srgb,var(--red) 35%,var(--line))}.hazard-badge.hazard-high{color:var(--yellow);border-color:color-mix(in srgb,var(--yellow) 35%,var(--line))}.hazard-badge.hazard-medium{color:var(--purple)}.hazard-badge.hazard-low{color:var(--green)}.notebook-entry{display:grid;grid-template-columns:auto 1fr auto;gap:12px;align-items:start;border:1px solid var(--line);border-radius:16px;padding:13px;background:var(--panel-glass);box-shadow:var(--shadow-sm)}.note-number{width:36px;height:36px;border-radius:11px;display:grid;place-items:center;background:var(--panel-soft);color:var(--primary);font-weight:950}.note-head{display:flex;justify-content:space-between;gap:10px}.note-head h3{margin:0;font-size:.9rem}.note-head small{color:var(--muted);font-size:.65rem}.notebook-entry p{margin:7px 0;color:var(--muted);font-size:.72rem;line-height:1.45}.notebook-entry code{display:block;border-radius:9px;padding:7px;background:var(--panel-soft);color:var(--primary);font-size:.68rem;white-space:normal}.notebook-entry ul{margin:8px 0 0;padding-left:18px;color:var(--muted);font-size:.7rem}.notebook-empty{display:grid;place-items:center;text-align:center;padding:28px}.notebook-empty span{font-size:2.2rem}.quiz-finish{text-align:center;padding:22px}.quiz-finish>span{font-size:3rem}.quiz-finish h3{margin:8px 0}.quiz-finish p{color:var(--muted)}.element-dialog .dialog-element-symbol.cat-Alkali-metal,.element-dialog .dialog-element-symbol.cat-Alkaline-earth-metal,.element-dialog .dialog-element-symbol.cat-Transition-metal,.element-dialog .dialog-element-symbol.cat-Post-transition-metal,.element-dialog .dialog-element-symbol.cat-Metalloid,.element-dialog .dialog-element-symbol.cat-Reactive-non-metal,.element-dialog .dialog-element-symbol.cat-Nonmetal,.element-dialog .dialog-element-symbol.cat-Halogen,.element-dialog .dialog-element-symbol.cat-Noble-gas,.element-dialog .dialog-element-symbol.cat-Lanthanide,.element-dialog .dialog-element-symbol.cat-Actinide{color:var(--text);box-shadow:var(--shadow-sm)}
@media(max-width:1100px){.element-explorer-grid{grid-template-columns:repeat(4,minmax(0,1fr))}.reaction-results{grid-template-columns:1fr}}
@media(max-width:780px){.element-profile-card .element-facts-line{grid-template-columns:1fr}.note-head{display:block}.notebook-entry{grid-template-columns:auto 1fr}.notebook-entry>.icon-btn{grid-column:1/-1;width:100%}.segmented-control{grid-template-columns:repeat(2,minmax(0,1fr))}}
@media(max-width:620px){.element-profile-card>p{min-height:0}.reaction-results{grid-template-columns:1fr}.profile-actions .btn{width:100%}}

/* Final consistency, mission arcade and responsive safeguards */
.safety-banner{display:flex;align-items:flex-start;gap:8px;padding:13px 15px;border:1px solid color-mix(in srgb,var(--yellow) 34%,var(--line));border-radius:16px;background:color-mix(in srgb,var(--yellow) 8%,var(--panel-glass));box-shadow:var(--shadow-sm);color:var(--muted);font-size:.78rem;line-height:1.55}.safety-banner strong{color:var(--text)}
.topic-top{display:flex;align-items:flex-start;justify-content:space-between;gap:7px;flex-wrap:wrap;min-width:0}.topic-top>*{min-width:0}.topic-top .confidence{max-width:100%;white-space:normal;text-align:center;justify-content:center}
.mission-tile{display:flex;flex-direction:column;min-width:0;padding:14px;border:1px solid var(--line);border-radius:17px;background:var(--panel-glass);box-shadow:var(--shadow-sm);transition:.18s}.mission-tile:hover{transform:translateY(-3px);border-color:var(--line-strong)}.mission-tile.complete{border-color:color-mix(in srgb,var(--green) 43%,var(--line));background:color-mix(in srgb,var(--green) 7%,var(--panel-glass))}.mission-icon{width:42px;height:42px;border-radius:13px;display:grid;place-items:center;background:linear-gradient(145deg,color-mix(in srgb,var(--primary) 15%,var(--panel)),color-mix(in srgb,var(--primary2) 14%,var(--panel)));font-size:1.25rem}.mission-tile>span{color:var(--primary);font-size:.65rem;font-weight:900;letter-spacing:.08em;text-transform:uppercase;margin-top:10px}.mission-tile h3{margin:6px 0;font-size:.94rem}.mission-tile p{flex:1;margin:0;color:var(--muted);font-size:.73rem;line-height:1.48}.mission-tile>div:last-child{display:flex;align-items:center;justify-content:space-between;gap:8px;margin-top:12px}.mission-tile>div:last-child strong{color:var(--yellow);font-size:.7rem}.mission-tile.complete>div:last-child strong{color:var(--green)}
.element-picker{width:min(1220px,calc(100% - 20px));max-height:94vh}.element-picker .periodic-scroll{max-width:100%}
@media(min-width:1151px){.progress-strip{grid-template-columns:repeat(6,minmax(0,1fr))}}
@media(max-width:620px){html,body{max-width:100%;overflow-x:hidden}.topic-top{flex-direction:column}.topic-top .confidence{align-self:flex-start}.mission-tile>div:last-child{align-items:stretch;flex-direction:column}.mission-tile>div:last-child .btn{width:100%}.safety-banner{display:block}.safety-banner strong{display:block;margin-bottom:4px}}

/* Final narrow-screen containment: later tablet rules must not restore multi-column element cards. */
@media(max-width:620px){
  .element-explorer-grid{grid-template-columns:minmax(0,1fr)!important}
  .element-profile-card,.element-profile-top,.element-profile-top>div{min-width:0;max-width:100%}
  .element-profile-top{grid-template-columns:54px minmax(0,1fr)}
  .element-profile-top h3,.element-profile-top small,.element-profile-top span{overflow-wrap:anywhere}
  .element-profile-card .element-facts-line{grid-template-columns:1fr}
}
@media(max-width:620px){
  .topic-grid{grid-template-columns:minmax(0,1fr)!important}
  .topic-card,.topic-card>*{min-width:0;max-width:100%}
  .topic-category{white-space:normal;overflow-wrap:anywhere}
}