.vsl{background:linear-gradient(180deg,#fbf9ff 0%,#f5f1fc 100%);padding:96px 0;color:#101438}
.vsl *{box-sizing:border-box}
.vsl-intro{display:grid;grid-template-columns:1.08fr .92fr;gap:70px;align-items:end}
.vsl-kicker{color:#4b2ebf;font-weight:800;font-size:.76rem;letter-spacing:.14em;text-transform:uppercase}
.vsl h2,.vsl h3,.vsl h4{font-family:Lora,Georgia,serif}
.vsl h2{font-size:clamp(2.4rem,5vw,4.4rem);line-height:1.04;margin:12px 0 20px;color:#101438}
.vsl-lead{color:#5e5366;font-size:1.07rem;line-height:1.8;max-width:710px}
.vsl-note{border-left:3px solid #c28a2e;padding:8px 0 8px 20px;color:#5e5366}
.vsl-path{display:grid;grid-template-columns:repeat(4,1fr);gap:10px;margin:44px 0}
.vsl-path article{background:#fff;border:1px solid #e2dced;border-radius:16px;padding:19px}
.vsl-path b{display:block;color:#4b2ebf;font-size:.72rem;letter-spacing:.1em}
.vsl-path strong{display:block;margin:6px 0}
.vsl-path span{font-size:.78rem;color:#6d6175}
.vsl-benefits{display:grid;grid-template-columns:1fr 1fr;gap:16px;margin:28px 0 44px}
.vsl-benefit{background:#101438;color:#fff;border-radius:22px;padding:28px}
.vsl-benefit:last-child{background:#29105f}
.vsl-benefit h3{font-size:1.45rem;margin:0 0 14px}
.vsl-benefit ul{margin:0;padding-left:18px;color:#e8e3f6}
.vsl-benefit li{margin:8px 0}

.subject-list{display:grid;gap:13px}
.subject{border:1px solid #d9d2e7;border-radius:20px;background:#fff;overflow:hidden}
.subject[open]{box-shadow:0 18px 42px rgba(38,17,79,.09);border-color:#b8aae0}
.subject summary{list-style:none;cursor:pointer;padding:23px 26px;display:grid;grid-template-columns:56px 1fr auto 24px;gap:18px;align-items:center}
.subject summary::-webkit-details-marker{display:none}
.subject-icon{width:54px;height:54px;border-radius:15px;display:grid;place-items:center;background:#e8e3f6;color:#4b2ebf;font-size:1.4rem;font-weight:800}
.subject summary h3{margin:0;font-size:1.45rem;color:#101438}
.subject summary p{margin:2px 0 0;color:#6d6175;font-size:.85rem}
.subject-status{font-size:.67rem;letter-spacing:.1em;text-transform:uppercase;font-weight:800;border-radius:99px;background:#f4f4f7;color:#6d6175;padding:7px 11px}
.subject-status.active{background:#e8f7f1;color:#16785f}
.chevron{font-size:1.4rem;color:#4b2ebf;transition:.2s}
.subject[open] .chevron{transform:rotate(45deg)}
.subject-content{padding:4px 26px 30px;border-top:1px solid #ece8f2}
.coming-content{padding:0 26px 25px;color:#6d6175;font-size:.9rem}

.sim-tabs{display:flex;gap:8px;overflow:auto;padding:24px 0 18px}
.sim-tab{border:1px solid #d8d2e4;background:#fff;color:#4d4760;padding:10px 14px;border-radius:10px;font-weight:750;font-size:.78rem;white-space:nowrap;cursor:pointer}
.sim-tab.active{background:#4b2ebf;color:#fff;border-color:#4b2ebf}
.sim-panel{display:none}
.sim-panel.active{display:block}
.simulator{border:1px solid #ded8e9;border-radius:18px;background:#fff;overflow:hidden}
.sim-title{padding:20px 22px;border-bottom:1px solid #e7e2ed}
.sim-title h4{margin:0;font-size:1.35rem}
.sim-title p{margin:4px 0 0;font-size:.8rem;color:#6d6175}
.sim-grid{display:grid;grid-template-columns:1.1fr .9fr}
.sim-stage{min-height:390px;display:grid;place-items:center;position:relative;background:radial-gradient(circle,#ece5ff 0,#fbfaff 55%,#fff)}
.atom-model{width:300px;height:300px;position:relative;display:grid;place-items:center}
#atomShells,#atomElectrons{position:absolute;inset:0;pointer-events:none}
.shell{position:absolute;border:1px solid rgba(75,46,191,.34);border-radius:50%}
.shell.s1{width:150px;height:150px}
.shell.s2{width:260px;height:260px}
.electron{width:13px;height:13px;background:#2683bb;box-shadow:0 0 0 4px rgba(38,131,187,.13);border-radius:50%;position:absolute;left:calc(50% - 6px);top:calc(50% - 6px);transform:rotate(var(--angle)) translateX(var(--radius))}
.nucleus{width:104px;height:104px;border-radius:50%;position:absolute;left:50%;top:50%;transform:translate(-50%,-50%);background:radial-gradient(circle,rgba(255,255,255,.96) 0 17%,rgba(238,232,248,.9) 68%,rgba(215,203,234,.82) 100%);z-index:2;box-shadow:0 8px 22px rgba(75,46,191,.2);border:1px solid #cfc4e1}
.nucleon{position:absolute;width:15px;height:15px;border-radius:50%;transform:translate(-50%,-50%);box-shadow:inset -2px -2px 3px rgba(16,20,56,.2),0 1px 2px rgba(16,20,56,.18)}
.nucleon.proton{background:#d04a67;border:1px solid #a32c49}.nucleon.neutron{background:#7163af;border:1px solid #51428b}
.particle-key{position:absolute;bottom:15px;font-size:.7rem;color:#6d6175}
.sim-controls{padding:24px}
.control{padding-bottom:15px;margin-bottom:15px;border-bottom:1px solid #e7e2ed}
.control label{display:flex;justify-content:space-between;font-size:.82rem;font-weight:700}
.control input[type=range]{width:100%;accent-color:#4b2ebf}
.element-result{border-radius:14px;background:#101438;color:#fff;padding:17px;display:flex;gap:13px;align-items:center}
.element-symbol{width:56px;height:62px;border:1px solid rgba(255,255,255,.42);display:grid;place-items:center;font:2rem Lora,serif}
.element-result strong,.element-result small{display:block}
.element-result small{color:#c5c0d3}
.insight{margin-top:13px;background:#fbf6e8;border-left:3px solid #c28a2e;padding:12px;font-size:.76rem;color:#5b513e}
.vsl-two{display:grid;grid-template-columns:1fr 1fr;gap:18px;padding:22px}
.data-box{border:1px solid #e0dbe8;border-radius:14px;padding:19px}
.data-box h4{margin:0 0 10px}
.mass-output{font-size:2.8rem;color:#4b2ebf;font-weight:800}
.bar-row{margin:14px 0}
.bar-row label{display:flex;justify-content:space-between;font-size:.76rem}
.bar{height:10px;background:#ebe8f0;border-radius:99px;overflow:hidden}
.bar i{display:block;height:100%;background:linear-gradient(90deg,#4b2ebf,#9577e8);border-radius:99px}
.vsl select,.vsl input[type=text]{width:100%;padding:11px;border:1px solid #d7d1e2;border-radius:9px;background:#fff}
.answer-row{display:flex;gap:8px}
.answer-row button{border:0;border-radius:9px;background:#4b2ebf;color:#fff;padding:10px 15px;font-weight:800}
.feedback{display:none;margin-top:12px;border-radius:9px;padding:11px;font-size:.78rem}
.feedback.good{display:block;background:#e9f7f2;color:#14755d}
.feedback.bad{display:block;background:#fff0f2;color:#9f2942}

.vsl-pricing{margin-top:55px}
.vsl-pricing-head{text-align:center;max-width:690px;margin:auto}
.vsl-pricing h3{font-size:2.2rem;margin:8px}
.plan-grid{display:grid;grid-template-columns:repeat(4,1fr);gap:12px;margin-top:28px}
.plan{position:relative;background:#fff;border:1px solid #ddd7e7;border-radius:17px;padding:22px;display:flex;flex-direction:column}
.plan.featured{border:2px solid #4b2ebf}
.plan h4{font-size:1.25rem;margin:0}
.plan .price{font-size:1.7rem;color:#4b2ebf;font-weight:800;margin:10px 0}
.plan p{font-size:.76rem;color:#6d6175}
.plan ul{padding-left:17px;font-size:.75rem;color:#514b61}
.plan a{margin-top:auto;text-align:center;padding:10px;border-radius:9px;background:#101438;color:#fff;font-size:.76rem;font-weight:800}
.coming-soon-plan{background:linear-gradient(145deg,#fbfaff,#f1edf9);border-style:dashed;padding-top:54px}
.coming-soon-plan .price{font-size:1.15rem;color:#352958}
.plan-status{position:absolute;top:18px;right:18px;padding:5px 9px;border-radius:999px;background:#e8e3f6;color:#341b6b;font-size:.68rem;font-weight:800;letter-spacing:.06em;text-transform:uppercase}
.plan-unavailable{margin-top:auto;text-align:center;padding:10px;border-radius:9px;background:#ded8eb;color:#5e5670;font-size:.76rem;font-weight:800}
.school-plan{text-align:center;margin-top:15px;font-size:.8rem;color:#6d6175}
.school-plan a{color:#4b2ebf;font-weight:800}

@media(max-width:900px){.vsl-intro,.sim-grid{grid-template-columns:1fr}
.vsl-path,.plan-grid{grid-template-columns:1fr 1fr}
.vsl-benefits{grid-template-columns:1fr}
.subject summary{grid-template-columns:50px 1fr 20px}
.subject-status{grid-column:2}
.sim-stage{min-height:340px}
}
@media(max-width:600px){.vsl{padding:72px 0}
.vsl-path,.plan-grid,.vsl-two{grid-template-columns:1fr}
.subject summary{padding:18px}
.subject-content{padding:4px 14px 20px}
.atom-model{width:270px;height:270px}
.shell.s2{width:230px;height:230px}
.sim-controls{padding:18px}
}

.vsl label{display:block;font-size:.82rem;font-weight:700;margin-bottom:14px}
.vsl label select,.vsl label input{margin-top:7px}
.vsl input[type=number]{width:100%;padding:11px;border:1px solid #d7d1e2;border-radius:9px}
.result-label{text-transform:uppercase;letter-spacing:.11em;color:#776b82;font-size:.7rem;font-weight:800}
.bond-stage{min-height:180px;display:flex;align-items:center;justify-content:center;gap:14px}
.bond-stage span{width:70px;height:70px;border-radius:50%;display:grid;place-items:center;background:#4b2ebf;color:white;font:1.5rem Lora,serif}
.bond-stage i{height:4px;width:70px;border-radius:4px;background:#c28a2e}
.bond-meter{height:12px;border-radius:99px;background:linear-gradient(90deg,#4b2ebf 0 18%,#c28a2e 45%,#d04a67 100%);position:relative}
.bond-meter i{position:absolute;width:4px;height:22px;background:#101438;top:-5px;border-radius:3px;left:0}
.geometry-stage{overflow:hidden}
.molecule-model{width:280px;height:280px;position:relative}
.molecule-model .central,.molecule-model .outer{position:absolute;border-radius:50%;display:grid;place-items:center}
.molecule-model .central{width:72px;height:72px;left:104px;top:104px;background:#4b2ebf;color:#fff;font-weight:800;z-index:2}
.molecule-model .outer{width:50px;height:50px;background:#c28a2e;color:#fff;font-weight:800;transform:translate(-50%,-50%)}
.molecule-model .bond{position:absolute;left:140px;top:138px;width:92px;height:4px;background:#80758d;transform-origin:left center}
.molecule-model .lone{position:absolute;width:26px;height:14px;transform:translate(-50%,-50%) rotate(var(--pair-angle,0deg));display:flex;justify-content:center;gap:4px;z-index:3}
.molecule-model .lone i{display:block;width:8px;height:8px;border-radius:50%;background:#d04a67;box-shadow:0 1px 2px rgba(16,20,56,.25)}
.shape-mark{width:56px;height:62px;border:1px solid rgba(255,255,255,.42);display:grid;place-items:center;font:1.5rem Lora,serif}
.balance-wrap{padding:24px}
.equation{padding:30px 12px;text-align:center;font:clamp(1.35rem,3vw,2.2rem) Lora,serif;background:#f7f4fc;border-radius:14px;margin:15px 0}
.coefficient-row{display:grid;grid-template-columns:repeat(4,1fr);gap:10px}
.coefficient-row label{text-align:center}
.coefficient-row input{width:100%;padding:9px;border:1px solid #d7d1e2;border-radius:8px;text-align:center}
.sim-action{border:0;border-radius:9px;background:#4b2ebf;color:#fff;padding:11px 16px;font-weight:800;cursor:pointer}
.atom-tally{display:grid;grid-template-columns:repeat(3,1fr);gap:8px;margin-top:15px}
.atom-tally span{padding:10px;border-radius:9px;background:#f5f2fa;text-align:center;font-size:.75rem}
.calculation-steps{font-size:.82rem;line-height:1.8;color:#62576d;margin-top:10px}
.coming-sims{display:grid;grid-template-columns:repeat(3,1fr);gap:9px;margin-top:16px}
.coming-sims div{padding:15px;border:1px dashed #c9bfdc;border-radius:12px;background:#faf8fd}
.coming-sims span,.coming-sims strong{display:block}
.coming-sims span{font-size:.65rem;text-transform:uppercase;letter-spacing:.1em;color:#8b7e99}
.coming-sims strong{font-size:.82rem;margin-top:3px}
.payment-roadmap{display:grid;grid-template-columns:repeat(4,1fr);gap:10px;margin-top:24px}
.payment-roadmap div{background:#fff;border:1px solid #ddd7e7;border-radius:14px;padding:17px}
.payment-roadmap b,.payment-roadmap span{display:block}
.payment-roadmap b{color:#101438}
.payment-roadmap span{font-size:.75rem;color:#6d6175;margin-top:5px;line-height:1.5}
.payment-note{text-align:center;color:#6d6175;font-size:.75rem;margin-top:13px}

@media(max-width:900px){.payment-roadmap{grid-template-columns:1fr 1fr}
}
@media(max-width:600px){.payment-roadmap,.coming-sims{grid-template-columns:1fr}
.coefficient-row{grid-template-columns:1fr 1fr}
.atom-tally{grid-template-columns:1fr}
}

.vsl-benefit h3{color:#fff}
.sim-tab{text-decoration:none;display:inline-flex;align-items:center}
.focus-nav{display:flex;justify-content:space-between;gap:16px;align-items:center;padding:18px 0 4px;font-size:.8rem}
.focus-nav a{color:#4b2ebf;font-weight:800}
.focus-nav span{color:#776b82;font-weight:700}
.simulation-focus header,.simulation-focus main>section:not(.vsl),.simulation-focus footer{display:none}
.simulation-focus .vsl{min-height:100vh;padding:28px 0}
.simulation-focus .vsl-intro,.simulation-focus .vsl-path,.simulation-focus .vsl-benefits,.simulation-focus .subject-list>details:not(:first-child),.simulation-focus .vsl-pricing,.simulation-focus .coming-sims{display:none}
.simulation-focus .subject{box-shadow:none;border:0;background:transparent}
.simulation-focus .subject>summary{display:none}
.simulation-focus .subject-content{padding:0;border:0}
.simulation-library{margin:18px 0 24px;border:1px solid #ddd6e8;border-radius:18px;background:#fff;box-shadow:0 12px 30px rgba(38,17,79,.08);overflow:hidden}.simulation-library>summary{display:flex;align-items:center;justify-content:space-between;gap:20px;padding:14px 18px;cursor:pointer;list-style:none}.simulation-library>summary::-webkit-details-marker{display:none}.simulation-library>summary span{display:grid;gap:2px}.simulation-library>summary small{color:#c28a2e;font-size:.62rem;font-weight:900;letter-spacing:.12em}.simulation-library>summary strong{color:#101438;font:700 1.08rem/1.25 Lora,Georgia,serif}.simulation-library>summary b{display:flex;align-items:center;gap:8px;padding:9px 13px;border-radius:999px;background:#f1edf8;color:#4b2ebf;font-size:.72rem}.simulation-library>summary i{font-size:1rem;font-style:normal;transition:transform .2s}.simulation-library[open]>summary i{transform:rotate(180deg)}
.simulation-focus .sim-tabs{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:10px;overflow:visible;margin:0;padding:6px 14px 16px;border-top:1px solid #eee9f4;background:#fbfaff}.simulation-group{min-width:0;padding:12px;border-radius:14px;background:#fff;border:1px solid #e7e1ef}.simulation-group h3{margin:0 0 10px;color:#766b82;font-size:.7rem;letter-spacing:.05em;text-transform:uppercase}.simulation-links{display:grid;gap:7px}.simulation-focus .sim-tab{display:grid;grid-template-columns:minmax(0,1fr) auto;align-content:center;gap:2px 7px;min-height:49px;padding:9px 10px;white-space:normal;background:#faf8fd;border-color:#e0daea;color:#4d4760;line-height:1.25;transition:border-color .15s ease,background .15s ease}.simulation-focus .sim-tab:hover{border-color:#8f7bd7;background:#f4f0fb}.simulation-focus .sim-tab.active{background:#4b2ebf;border-color:#4b2ebf;color:#fff}.simulation-focus .sim-tab .access-label{grid-column:1/-1;margin-top:2px;color:#776b82;font-size:.58rem}.simulation-focus .sim-tab.active .access-label{color:#e5dcff}
.simulation-focus .simulator{box-shadow:0 22px 60px rgba(38,17,79,.12)}
@media(max-width:900px){.simulation-focus .sim-tabs{grid-template-columns:1fr}.simulation-group{padding:10px}.simulation-links{grid-template-columns:repeat(2,minmax(0,1fr))}}
@media(max-width:600px){.focus-nav{align-items:flex-start;flex-direction:column}.simulation-library>summary b{padding:8px 10px}.simulation-links{grid-template-columns:1fr}
.simulation-focus .vsl{padding-top:16px}
}

.simulation-launch-note{margin:24px 0 12px;color:#6d6175;font-size:.86rem}
body:not(.simulation-focus) .subject-content>.sim-panel{display:none}
body:not(.simulation-focus) .sim-tabs{display:grid;grid-template-columns:repeat(4,1fr);gap:10px;padding:0 0 8px;overflow:visible}
body:not(.simulation-focus) .sim-tab{justify-content:space-between;min-height:54px;background:#4b2ebf;color:#fff;border-color:#4b2ebf;font-size:.82rem;box-shadow:0 8px 18px rgba(75,46,191,.13)}
body:not(.simulation-focus) .sim-tab:hover{background:#29105f;border-color:#29105f;transform:translateY(-2px)}
body:not(.simulation-focus) .sim-tab span{color:#d8c8ff;font-size:1rem}
.science-tools-content{display:grid;grid-template-columns:repeat(3,1fr);gap:12px;padding:22px 26px 28px;border-top:1px solid #ece8f2}.science-tool-card{display:grid;grid-template-columns:auto 1fr;gap:12px;align-items:start;min-height:145px;padding:18px;border:1px solid #ddd6e9;border-radius:16px;background:#fbfaff}.science-tool-card .tool-mark{display:grid;place-items:center;width:42px;height:42px;border-radius:12px;background:#e9e3f8;color:#4b2ebf;font-weight:900}.science-tool-card>span:nth-child(2){display:grid}.science-tool-card strong{color:#101438;font-size:.82rem}.science-tool-card small{margin-top:5px;color:#6d6175;font-size:.68rem;line-height:1.5}.science-tool-card b{grid-column:1/-1;align-self:end;color:#4b2ebf;font-size:.66rem}.science-tool-card.available{border-color:#9f8bdd;background:#f7f3ff;box-shadow:0 8px 18px rgba(75,46,191,.1)}.science-tool-card.available:hover{border-color:#4b2ebf;transform:translateY(-2px)}.science-tool-card.upcoming{opacity:.72}.science-tool-card.upcoming b{color:#786f84}
.simulation-focus .simulation-launch-note{display:none}
@media(max-width:900px){body:not(.simulation-focus) .sim-tabs{grid-template-columns:1fr 1fr}
.science-tools-content{grid-template-columns:1fr}
}
@media(max-width:520px){body:not(.simulation-focus) .sim-tabs{grid-template-columns:1fr}
}

.atom-head{display:flex;justify-content:space-between;gap:20px;align-items:center}
.mode-switch{display:flex;background:#eee9f7;border-radius:11px;padding:4px}
.mode-btn{border:0;background:transparent;color:#5c5069;border-radius:8px;padding:9px 13px;font-weight:800;cursor:pointer}
.mode-btn.active{background:#4b2ebf;color:#fff;box-shadow:0 4px 12px rgba(75,46,191,.22)}
.atom-mode-note{display:flex;gap:10px;align-items:center;padding:12px 22px;background:#f6f2fc;border-bottom:1px solid #e7e2ed;font-size:.78rem}
.atom-mode-note strong{color:#4b2ebf}
.atom-mode-note span{color:#6d6175}
.atom-stage{min-height:480px;align-content:center}
.advanced-model{width:390px;height:390px}
.dynamic-shell{position:absolute;left:50%;top:50%;transform:translate(-50%,-50%);border:1px solid rgba(75,46,191,.3);border-radius:50%}
.advanced-model .electron{z-index:3}
.nuclear-notation{position:absolute;right:18px;top:18px;border:1px solid #d9d1e7;border-radius:10px;background:#fff;padding:12px 16px;color:#29105f;font:1.5rem Lora,serif}
.nuclear-notation sup,.nuclear-notation sub{font-size:.65em}
.element-picker{font-weight:800}
.atom-challenge{display:grid;grid-template-columns:1fr auto;gap:14px;align-items:center;padding:22px;border-top:1px solid #e7e2ed;background:#fbf9ff}
.atom-challenge h4{margin:5px 0;font-size:1.2rem}
.atom-challenge p{margin:0;color:#6d6175;font-size:.78rem}
.challenge-kicker{color:#4b2ebf;font-size:.68rem;letter-spacing:.12em;text-transform:uppercase;font-weight:800}
.challenge-actions{display:flex;gap:8px}
.secondary-action{border:1px solid #4b2ebf;border-radius:9px;background:#fff;color:#4b2ebf;padding:10px 14px;font-weight:800;cursor:pointer}
.atom-challenge .feedback{grid-column:1/-1;margin:0}
.advanced-feature-strip{display:grid;grid-template-columns:repeat(4,1fr);background:#101438;color:#dcd7eb}
.advanced-feature-strip span{padding:15px;text-align:center;border-right:1px solid rgba(255,255,255,.1);font-size:.72rem}
.advanced-feature-strip b{color:#d7ae54}
@media(max-width:900px){.atom-stage{min-height:440px}
.atom-challenge{grid-template-columns:1fr}
.challenge-actions{justify-content:flex-start}
.advanced-feature-strip{grid-template-columns:1fr 1fr}
}

.teacher-preview h3{display:flex;align-items:center;justify-content:space-between;gap:12px;flex-wrap:wrap}
.coming-soon-badge{display:inline-flex;align-items:center;border-radius:999px;background:#c28a2e;color:#101438;padding:6px 11px;font-family:Montserrat,Arial,sans-serif;font-size:.66rem;font-weight:900;letter-spacing:.08em;text-transform:uppercase}
.coming-soon-note{margin:-5px 0 12px;color:#d8cfee;font-size:.78rem;font-weight:700}
.sim-tab.premium-simulation{position:relative;padding-right:14px}.access-label{display:block;margin-top:2px;color:#756b84;font-size:.58rem;font-weight:800;letter-spacing:.04em;text-transform:uppercase}.sim-tab.premium-simulation:not(.access-granted):before{content:"🔒";font-size:.66rem}.sim-tab.premium-simulation.access-granted:before{content:"✓";color:#168165;font-weight:900}.access-modal{position:fixed;inset:0;z-index:100;display:none;place-items:center;padding:20px;background:rgba(10,12,40,.72);backdrop-filter:blur(8px)}.access-modal.visible{display:grid}.access-dialog{position:relative;width:min(520px,100%);border-radius:26px;background:#fff;padding:34px;box-shadow:0 24px 70px rgba(0,0,0,.28);text-align:left}.access-dialog h2{margin:7px 0 10px;font-size:2rem}.access-dialog p{color:#655d76}.access-dialog>small{display:block;margin-top:18px;color:#756b84}.access-kicker{color:#c28a2e;font-size:.72rem;font-weight:900;letter-spacing:.12em;text-transform:uppercase}.access-close{position:absolute;right:18px;top:14px;border:0;background:none;color:#655d76;font-size:1.7rem;cursor:pointer}.access-actions{display:flex;gap:10px;flex-wrap:wrap;margin-top:22px}.simulation-locked .subject-content{visibility:hidden}.simulation-locked .access-modal{visibility:visible}
.access-inline{margin-left:4px;font-size:.52rem;font-weight:900;letter-spacing:.05em;text-transform:uppercase}.mode-btn[data-atom-mode="advanced"]:not(.access-granted):before{content:"🔒 ";font-size:.66rem}
@media(max-width:600px){.atom-head{align-items:flex-start;flex-direction:column}
.atom-mode-note{align-items:flex-start;flex-direction:column}
.advanced-model{width:300px;height:300px;transform:scale(.82)}
.atom-stage{min-height:380px}
.challenge-actions{flex-direction:column}
.advanced-feature-strip{grid-template-columns:1fr 1fr}
}