:root{color-scheme:dark;--ink:#e6faf6;--muted:#98babd;--line:#29555e;--mint:#a3f3d0;--blue:#73dbef;--panel:#102e3c;--error:#ffada4;font-family:Inter,ui-sans-serif,system-ui,-apple-system,BlinkMacSystemFont,'Segoe UI',sans-serif;background:#08222f;color:var(--ink)}*{box-sizing:border-box}body{margin:0;min-height:100vh;background:radial-gradient(ellipse at 90% 0%,#126b7270,transparent 45%),radial-gradient(ellipse at 5% 55%,#155b7880,transparent 55%),linear-gradient(160deg,#09222f,#0b3942 70%,#0b4746);background-attachment:fixed}button,input,select,textarea{font:inherit}button,a,input,select,textarea{outline-offset:5px}button{border:1px solid #41656d;background:#143945;color:var(--ink);border-radius:12px;padding:12px 19px;cursor:pointer;font-weight:650;transition:background .15s,transform .15s}button:hover{background:#245360;transform:translateY(-1px)}button:disabled{opacity:.45;cursor:not-allowed;transform:none}.primary{background:var(--mint);border-color:var(--mint);color:#0a3436}.primary:hover{background:#c1ffdf}.danger{color:#ffc2b8}.topbar{max-width:1180px;margin:auto;padding:30px 32px;display:flex;justify-content:space-between;align-items:center;border-bottom:1px solid #ffffff17}.topbar a{display:flex;align-items:center;gap:10px;text-decoration:none;color:var(--ink);font-size:28px;font-weight:750;letter-spacing:-1px}.logo{font-size:37px;color:var(--mint)}.brand-sub{font-size:10px;letter-spacing:2px;color:var(--muted);border-left:1px solid var(--line);margin-left:12px;padding-left:20px}.badge,.eyebrow{text-transform:uppercase;font-size:11px;letter-spacing:2px;color:var(--mint);font-weight:750}.badge{border:1px solid var(--line);padding:10px 13px;border-radius:24px}main{max-width:1120px;margin:48px auto;padding:0 28px;position:relative;z-index:1}.hero{display:flex;justify-content:space-between;gap:25px;align-items:center;margin-bottom:36px}h1{font-size:clamp(36px,5vw,58px);font-weight:600;letter-spacing:-2px;line-height:1.08;margin:12px 0 18px}h1 em{font-style:normal;color:var(--mint)}h2{font-size:21px;letter-spacing:-.5px;margin:0 0 13px}h3{font-size:16px;margin:0 0 8px}p{line-height:1.6}.muted,.description{color:var(--muted)}.description{font-size:13px;line-height:1.6;margin:5px 0 0}.hero p{max-width:530px;color:var(--muted);margin:0}.grid{display:grid;grid-template-columns:1.2fr 1fr;gap:22px}.panel{background:linear-gradient(135deg,#16414fed,#0c2f3ded);border:1px solid var(--line);border-radius:20px;padding:26px;box-shadow:0 12px 35px #03151b20}.section-head{display:flex;justify-content:space-between;align-items:center;gap:16px;margin-bottom:18px}.pill{background:#86e8d315;color:var(--mint);padding:6px 10px;border:1px solid #6dc7c336;border-radius:20px;font-size:11px;white-space:nowrap}.mode{display:flex;gap:14px;align-items:center;padding:17px 0;border-top:1px solid #ffffff0e;cursor:pointer}.mode .number{font-family:monospace;color:#6eabb6;font-size:13px}.mode-text{flex:1}.mode strong{font-size:15px}.mode input{appearance:none;width:38px;height:22px;background:#254c57;border-radius:16px;border:1px solid #4d747e;position:relative;cursor:pointer;flex-shrink:0}.mode input:after{content:'';position:absolute;width:14px;height:14px;left:3px;top:3px;border-radius:50%;background:#8aacb5}.mode input:checked{background:var(--mint);border-color:var(--mint)}.mode input:checked:after{background:#124d4b;left:19px}.stack{display:flex;flex-direction:column;gap:20px}.settings-panel{margin-top:22px}.settings-grid{display:grid;grid-template-columns:repeat(2,1fr);gap:20px}.field{display:flex;flex-direction:column;gap:7px;font-size:13px;color:#b8d6d8;margin:14px 0}.field input,.field select,textarea{width:100%;background:#092733;border:1px solid #365b66;border-radius:9px;color:var(--ink);padding:11px 13px}.row{display:flex;gap:14px}.row>*{flex:1}input[type=checkbox]{accent-color:var(--mint)}.check{display:flex;gap:9px;align-items:center;font-size:13px;line-height:1.5;margin-top:15px}.actions{display:flex;gap:12px;align-items:center;flex-wrap:wrap}.startbar{display:flex;justify-content:space-between;align-items:center;gap:15px;margin-top:24px;padding:20px 26px}.startbar p{margin:0;font-size:13px;color:var(--muted)}.fine{font-size:12px;color:var(--muted);line-height:1.65}details{margin-top:18px}summary{cursor:pointer;color:var(--mint);font-size:13px}textarea{min-height:130px;resize:vertical;font-family:monospace;font-size:12px}.data-tools{display:grid;grid-template-columns:1fr 1fr;gap:20px;margin-top:20px}.wide{grid-column:1/-1}.session{max-width:760px;margin:0 auto}.session-head{display:flex;justify-content:space-between;align-items:center;margin-bottom:24px}.question{padding:38px;text-align:center}.question h1{font-size:42px;margin:35px 0 15px;overflow-wrap:anywhere}.question .prompt{color:var(--muted);margin-bottom:24px}.answer-form{max-width:480px;margin:25px auto 0}.answer-form input{font-size:19px}.choices{display:grid;grid-template-columns:repeat(2,1fr);gap:12px;margin:24px 0}.choices button{min-height:55px;overflow-wrap:anywhere}.feedback{margin-top:22px;border:1px solid #6acb9b88;background:#72e6ac10;padding:18px;border-radius:12px;text-align:left}.feedback.wrong{border-color:#ed908888;background:#df6c6312}.feedback strong{color:var(--mint)}.feedback.wrong strong{color:var(--error)}.session-bottom{display:flex;justify-content:space-between;margin-top:24px;align-items:center}.metric-grid{display:grid;grid-template-columns:repeat(3,1fr);gap:18px;margin-bottom:24px}.metric b{font-size:30px;display:block;margin:14px 0 5px}.metric small{color:var(--muted)}.chart-grid{display:grid;grid-template-columns:1fr 1fr;gap:22px;margin:24px 0}.chart{width:100%;height:auto;overflow:visible}.chart text{font-size:11px;fill:#a1c3c8}.legend{display:flex;gap:16px;color:var(--muted);font-size:11px;flex-wrap:wrap}.dot{color:var(--mint)}.dash{color:var(--blue)}.table-wrap{overflow:auto;max-height:520px}table{border-collapse:collapse;width:100%;font-size:12px;text-align:left}th,td{padding:12px;border-bottom:1px solid #ffffff12;vertical-align:top}th{color:var(--muted);white-space:nowrap;background:#113440;position:sticky;top:0}td{min-width:70px}footer{max-width:850px;text-align:center;margin:60px auto 30px;padding:0 30px;color:#7dabad;font-size:11px;line-height:1.8;position:relative}#particles{position:fixed;inset:0;pointer-events:none;overflow:hidden;z-index:0}.particle{position:absolute;opacity:.09;will-change:transform}.particle.phrase{opacity:.12;color:#b2f2e2;font-size:12px;white-space:pre-line;width:180px;font-weight:700}dialog{background:#103543;color:var(--ink);border:1px solid var(--line);border-radius:20px;max-width:480px;padding:30px}dialog::backdrop{background:#03141cbf;backdrop-filter:blur(5px)}#toast{position:fixed;bottom:24px;left:50%;transform:translateX(-50%);background:#d3ffee;color:#0a3535;padding:12px 22px;border-radius:12px;z-index:5;display:none;max-width:90vw}.error{color:var(--error)}code{color:#c0eae4;overflow-wrap:anywhere}.empty{text-align:center;padding:35px;color:var(--muted)}.correct-counters .total-row td{font-weight:750;color:var(--mint);border-top:1px solid var(--line)}@media(max-width:750px){.grid,.settings-grid,.chart-grid,.data-tools{grid-template-columns:1fr}.metric-grid{grid-template-columns:1fr}.brand-sub,.badge{display:none}.topbar{padding:18px 24px}main{padding:0 18px;margin-top:32px}.panel{padding:22px}.question{padding:25px 18px}.question h1{font-size:33px}.startbar{align-items:flex-start;flex-direction:column}.startbar button{width:100%}.wide{grid-column:auto}.row{flex-wrap:wrap}.row>*{min-width:100px}}@media(prefers-reduced-motion:reduce){*{scroll-behavior:auto!important;transition:none!important}.particle{will-change:auto}}
/* Decorative objects only receive clicks through uncovered space. */
.topbar{position:relative;z-index:1}main{pointer-events:none}main .panel,main .hero,main .session-head,main .session-bottom{pointer-events:auto}.particle{pointer-events:auto;cursor:crosshair;object-fit:contain;user-select:none}.particle.phrase{display:flex;align-items:center;justify-content:center;text-align:center;white-space:pre-line;overflow:hidden;font-size:12px}#effects-layer{position:fixed;inset:0;pointer-events:none;z-index:2;overflow:hidden}.object-shard{position:absolute;overflow:hidden;pointer-events:none;will-change:transform,opacity}.shard-content{object-fit:contain;white-space:pre-line;font-size:12px;color:#b2f2e2;font-weight:700;display:flex;align-items:center;justify-content:center;text-align:center}.explosion-flash{position:absolute;object-fit:contain;pointer-events:none}#jumpscare-overlay{position:fixed;inset:0;background:#000;z-index:2147483647;display:grid;place-items:center;outline:none}#jumpscare-overlay:not([open]){display:none}#jumpscare-overlay img{display:none;max-width:90vw;max-height:90vh;width:min(70vmin,650px);object-fit:contain}#jumpscare-overlay.revealed img{display:block}body:has(#jumpscare-overlay[open]){overflow:hidden}

#jumpscare-overlay{margin:0;border:0;padding:0;border-radius:0;width:100vw;height:100dvh;max-width:none;max-height:none}#jumpscare-overlay::backdrop{background:#000;backdrop-filter:none}

/* Long program name wraps comfortably on narrow screens. */
.topbar a{font-size:clamp(19px,2.2vw,27px);line-height:1.3;letter-spacing:-.5px;display:block;overflow-wrap:break-word}

/* Crisp, unscaled square explosion crops. Motion uses pixel-snapped positions. */
.object-shard{border-radius:0;transform:none;filter:none;backdrop-filter:none;will-change:auto;contain:paint;opacity:1}
.shard-content{transform:none!important;filter:none;image-rendering:pixelated}

/* Revealed once an individual image reaches fifteen explosions. */
#explosion-counter{position:fixed;bottom:16px;left:16px;z-index:3;width:280px;max-width:calc(100vw - 32px);max-height:min(35vh,320px);overflow:auto;border:1px solid var(--line);border-radius:12px;background:#103543f5;box-shadow:0 8px 30px #03151b60}
#explosion-counter[hidden]{display:none}
#explosion-counter caption{text-align:left;padding:12px;font-weight:700;color:var(--mint)}
#explosion-counter th,#explosion-counter td{padding:8px 12px;vertical-align:middle}
#explosion-counter td:first-child{overflow-wrap:anywhere}
#explosion-counter td:last-child{width:60px;text-align:right;font-variant-numeric:tabular-nums}
#explosion-counter img{width:28px;height:28px;object-fit:contain;vertical-align:middle;margin-right:8px}

/* Flat, adjoining study-type tabs; subtypes open below the selected tab. */
.topbar{flex-wrap:wrap;gap:12px;z-index:4}.topbar #brand{flex-basis:100%}
#study-navigation{display:grid;grid-template-columns:repeat(5,minmax(0,1fr));gap:0;position:relative;width:100%;border:1px solid var(--line);background:#103543}
.study-type{position:relative;margin:0;min-width:0;border-right:1px solid var(--line)}.study-type:last-of-type{border-right:0}
.study-type-tab{display:flex;align-items:center;justify-content:center;height:100%;min-height:48px;list-style:none;border:0;border-radius:0;padding:12px 10px;background:#103543;color:var(--ink);font-size:14px;letter-spacing:0;text-align:center;cursor:pointer;box-shadow:none}
.study-type-tab::-webkit-details-marker{display:none}
.study-type.selected .study-type-tab{background:#1d4b55;color:var(--mint)}.study-type[open] .study-type-tab,.study-type-tab:hover{background:#245360;color:var(--mint)}
.study-type-tab:focus-visible{outline:2px solid var(--mint);outline-offset:-3px}
.study-subtypes{position:absolute;top:100%;left:-1px;min-width:230px;max-width:calc(100vw - 48px);padding:0;background:#103543;border:1px solid var(--line);border-radius:0;box-shadow:none}
.study-type:nth-last-of-type(-n+2) .study-subtypes{left:auto;right:-1px}
.study-subtypes :is(button,a){display:flex;align-items:center;justify-content:space-between;gap:12px;width:100%;text-align:left;border:0;border-bottom:1px solid #ffffff12;background:transparent;border-radius:0;padding:12px;transform:none;font-size:14px}
.study-subtypes :is(button,a):last-child{border-bottom:0}.study-subtypes :is(button,a):hover{background:#245360}.study-subtypes :is(button,a)[aria-current="page"]{color:var(--mint);background:#a3f3d015}
.study-subtypes :is(button,a):disabled{opacity:.7}.study-coming-soon{font-size:10px;color:var(--muted);white-space:nowrap;font-weight:400}
.active-study{font-size:12px;color:var(--muted)}
@media(max-width:600px){.study-type-tab{font-size:11px;padding:10px 4px;min-height:62px;overflow-wrap:anywhere}.study-subtypes{min-width:210px}}

.study-subtypes a{color:var(--ink);text-decoration:none;font-weight:650}
.landing{margin-top:clamp(60px,12vh,140px)}

.math-areas{max-width:760px}.math-topic-list{list-style:none;margin:0;padding:0}.math-topic-list li{display:flex;align-items:center;justify-content:space-between;gap:16px;padding:18px 0;border-top:1px solid #ffffff12;font-weight:650}.math-topic-list .pill{font-weight:400;letter-spacing:0}