:root{--bg: #ffffff;--card: #ffffff;--ink: #3b3530;--muted: #8f867c;--line: #ebe5de;--ember: #ff8a1f;--ember-dark: #e06c00;--ember-soft: #fff2e4;--good: #34c06e;--good-dark: #22a057;--good-soft: #e4f8ec;--good-ink: #1d8a4b;--bad: #ff5d55;--bad-dark: #df3f38;--bad-soft: #ffeceb;--bad-ink: #d33a33;--sky: #2fa4f5;--sky-dark: #1a86d4;--sky-soft: #e5f4fe;--off: #e8e3dd;--off-ink: #b3aaa0;--ui: "Nunito", ui-rounded, system-ui, sans-serif;color-scheme:light}@media(prefers-color-scheme:dark){:root:not([data-theme=light]){--bg: #1a1613;--card: #221d19;--ink: #f4ede5;--muted: #a59a8e;--line: #3a322b;--ember-soft: #3a2614;--good-soft: #15301f;--good-ink: #5fd690;--bad-soft: #3a1b19;--bad-ink: #ff8a83;--sky-soft: #142a3a;--off: #3a322b;--off-ink: #786d62;color-scheme:dark}}:root[data-theme=dark]{--bg: #1a1613;--card: #221d19;--ink: #f4ede5;--muted: #a59a8e;--line: #3a322b;--ember-soft: #3a2614;--good-soft: #15301f;--good-ink: #5fd690;--bad-soft: #3a1b19;--bad-ink: #ff8a83;--sky-soft: #142a3a;--off: #3a322b;--off-ink: #786d62;color-scheme:dark}*{box-sizing:border-box}body{margin:0;background:var(--bg);color:var(--ink);font-family:var(--ui);font-size:17px;font-weight:600;line-height:1.5;-webkit-tap-highlight-color:transparent}main{max-width:640px;margin:0 auto;padding:0 16px 140px}body.engine-on main:has(.engine){max-width:1040px;display:grid;grid-template-columns:minmax(0,1fr) 320px;gap:32px;align-items:start}body:not(.engine-on) .engine{display:none}@media(max-width:860px){body.engine-on main:has(.engine){grid-template-columns:minmax(0,1fr)}}h1{font-size:clamp(26px,6vw,34px);line-height:1.15;font-weight:900;margin:0 0 10px}h2{font-size:20px;font-weight:900;margin:32px 0 12px}p{margin:0 0 12px}.lede{font-size:18px;color:var(--muted);font-weight:700}.center{text-align:center}code{font-family:var(--ui);font-weight:900;font-variant-numeric:tabular-nums;background:var(--off);border-radius:8px;padding:1px 7px;white-space:nowrap}.btn{--c: var(--ember);--d: var(--ember-dark);display:inline-flex;align-items:center;justify-content:center;gap:8px;font:inherit;font-size:16px;font-weight:900;text-transform:uppercase;letter-spacing:.06em;color:#fff;background:var(--c);border:0;border-radius:16px;padding:14px 24px;min-height:52px;box-shadow:0 4px 0 var(--d);cursor:pointer;text-decoration:none;transition:filter .1s}.btn:hover{filter:brightness(1.05)}.btn:active{transform:translateY(4px);box-shadow:0 0 0 var(--d)}.btn:disabled{--c: var(--off);--d: var(--off);color:var(--off-ink);cursor:default;filter:none;transform:none}.btn.good{--c: var(--good);--d: var(--good-dark)}.btn.bad{--c: var(--bad);--d: var(--bad-dark)}.btn.ghost{background:var(--card);color:var(--sky);border:2px solid var(--line);box-shadow:0 4px 0 var(--line)}.btn.ghost:active{box-shadow:0 0 0 var(--line)}.btn.block{display:flex;width:100%}.btns{display:grid;gap:14px;margin-top:28px}.link{font:inherit;font-weight:800;color:var(--sky);background:none;border:0;padding:0;cursor:pointer;text-decoration:none}.links{display:flex;flex-wrap:wrap;justify-content:center;gap:6px 18px;margin-top:36px;font-size:14px}.links .link{color:var(--muted)}.hud{display:flex;align-items:center;gap:16px;padding:16px 0;border-bottom:2px solid var(--line);margin-bottom:28px}.brand{display:flex;align-items:center;gap:8px;font-weight:900;font-size:20px;color:var(--ember);letter-spacing:-.01em}.brand .mascot{animation:none}.stat{display:flex;align-items:center;gap:5px;font-weight:900;font-size:17px}.stat:first-of-type{margin-left:auto}.stat.off{color:var(--off-ink)}.stat.flame{color:var(--ember)}.stat.fixed{color:var(--good)}.stat svg{width:24px;height:24px}.stat.off svg{filter:grayscale(1);opacity:.45}.lessonbar{display:flex;align-items:center;gap:16px;padding:20px 0 8px}.close{flex:none;width:32px;height:32px;display:grid;place-items:center;background:none;border:0;color:var(--off-ink);cursor:pointer;padding:0}.close svg{width:22px;height:22px}.bar{flex:1;height:16px;border-radius:999px;background:var(--off);overflow:hidden}.bar b{display:block;height:100%;min-width:16px;border-radius:999px;background:var(--ember);box-shadow:inset 0 -4px #00000014,inset 0 4px #ffffff47;transition:width .45s cubic-bezier(.3,1.4,.6,1)}.bar.good b{background:var(--good)}.count{flex:none;font-weight:900;color:var(--muted);font-size:15px}.mascot{flex:none;color:var(--ink);animation:bob 2.8s ease-in-out infinite}.mascot .flame{transform-origin:60px 106px;animation:flicker .9s ease-in-out infinite alternate}.mood-cheer{animation:hop .9s ease-in-out infinite}@keyframes bob{50%{transform:translateY(-4px)}}@keyframes hop{0%,to{transform:translateY(0)}40%{transform:translateY(-10px) rotate(-3deg)}60%{transform:translateY(-10px) rotate(3deg)}}@keyframes flicker{to{transform:scale(1.08,.92)}}@media(prefers-reduced-motion:reduce){.mascot,.mascot .flame{animation:none}}.say{display:flex;align-items:center;gap:14px;margin:8px 0 24px}.bubble{position:relative;border:2px solid var(--line);border-radius:18px;padding:14px 18px;font-weight:800;font-size:17px;background:var(--card)}.bubble:before,.bubble:after{content:"";position:absolute;top:50%;border:10px solid transparent;transform:translateY(-50%)}.bubble:before{left:-21px;border-right-color:var(--line)}.bubble:after{left:-17px;border-right-color:var(--card)}.bubble p:last-child{margin:0}.bubble small{display:block;color:var(--muted);font-weight:700;font-size:15px;margin-top:4px}.hero{display:flex;flex-direction:column;align-items:center;text-align:center;padding-top:24px}.hero .mascot{margin-bottom:18px}.hero .lede{max-width:440px}.tiles{display:grid;gap:12px;margin:0;padding:0;list-style:none}.tile{display:flex;align-items:center;gap:14px;width:100%;text-align:left;font:inherit;color:inherit;background:var(--card);border:2px solid var(--line);border-bottom-width:4px;border-radius:18px;padding:14px 16px}button.tile{cursor:pointer}button.tile:active{transform:translateY(2px);border-bottom-width:2px;margin-bottom:2px}button.tile:hover{background:color-mix(in srgb,var(--line) 25%,var(--card))}.tile .name{display:block;font-weight:800;line-height:1.3}.tile .sub{display:block;font-size:14px;font-weight:800;color:var(--muted)}.tile .go{margin-left:auto;color:var(--off-ink);flex:none;display:flex}.tile .go svg{width:22px;height:22px}.badge{flex:none;width:44px;height:44px;border-radius:50%;display:grid;place-items:center;color:#fff;background:var(--c, var(--ember));box-shadow:0 3px 0 var(--d, var(--ember-dark))}.badge svg{width:22px;height:22px}.badge.good{--c: var(--good);--d: var(--good-dark)}.badge.sky{--c: var(--sky);--d: var(--sky-dark)}.badge.bad{--c: var(--bad);--d: var(--bad-dark)}.tile .sub.due{color:var(--sky)}.tile .sub.work{color:var(--ember)}.tile .sub.ok{color:var(--good-ink)}.callout{border-radius:20px;padding:18px 20px;margin:0 0 20px;border:2px solid var(--b, var(--line));background:var(--s, var(--card))}.callout .label{display:block;font-size:13px;font-weight:900;text-transform:uppercase;letter-spacing:.08em;color:var(--k, var(--muted));margin-bottom:4px}.callout .big{font-size:21px;font-weight:900;line-height:1.3;margin:0 0 6px}.callout p:last-child{margin:0}.callout.ember{--b: color-mix(in srgb, var(--ember) 40%, transparent);--s: var(--ember-soft);--k: var(--ember-dark)}.callout.good{--b: color-mix(in srgb, var(--good) 40%, transparent);--s: var(--good-soft);--k: var(--good-ink)}.callout.sky{--b: color-mix(in srgb, var(--sky) 40%, transparent);--s: var(--sky-soft);--k: var(--sky-dark)}.stats{display:grid;grid-template-columns:repeat(auto-fit,minmax(96px,1fr));gap:12px;width:100%;margin:24px 0 0}.stats div{border:2px solid var(--c);border-radius:16px;overflow:hidden;text-align:center}.stats dt{background:var(--c);color:#fff;font-size:12px;font-weight:900;text-transform:uppercase;letter-spacing:.08em;padding:4px 6px}.stats dd{margin:0;padding:10px 6px;font-size:20px;font-weight:900;color:var(--c)}.stats .ember{--c: var(--ember)}.stats .good{--c: var(--good)}.stats .sky{--c: var(--sky)}.prompt{font-size:24px;font-weight:900;margin:24px 0 4px}.chip{display:inline-block;border-radius:999px;padding:3px 12px;font-size:13px;font-weight:900;text-transform:uppercase;letter-spacing:.06em;background:var(--ember-soft);color:var(--ember-dark)}.chip.sky{background:var(--sky-soft);color:var(--sky-dark)}.sum{--gap: .14em;width:fit-content;margin:28px auto 8px;font-size:clamp(48px,13vw,68px);font-weight:900;font-variant-numeric:tabular-nums;line-height:1.12}.problem{display:grid;grid-template-columns:repeat(var(--cols),calc(1ch + var(--gap)));justify-content:end}.problem .sign{color:var(--ember)}.problem .rule{grid-column:1 / -1;height:5px;border-radius:3px;background:var(--ink);margin:6px 0 10px}.sum input{display:block;width:calc(var(--cols) * (1ch + var(--gap)) + 24px);margin:0 -12px;padding:2px 12px;font:inherit;letter-spacing:var(--gap);text-align:right;color:var(--sky);background:var(--off);border:3px solid transparent;border-radius:16px;outline:none;caret-color:var(--sky)}.sum input:focus{border-color:var(--sky);background:var(--sky-soft)}.sum input::placeholder{color:var(--off-ink)}.sum.ok input{color:var(--good-ink);background:var(--good-soft);border-color:var(--good)}.sum.bad input{color:var(--bad-ink);background:var(--bad-soft);border-color:var(--bad)}.hint{text-align:center;color:var(--muted);font-size:14px;font-weight:700;margin-top:18px}.shake{animation:shake .3s}@keyframes shake{25%{transform:translate(-6px)}75%{transform:translate(6px)}}.foot{position:fixed;left:0;right:0;bottom:0;z-index:10;background:var(--bg);border-top:2px solid var(--line);padding:18px 16px calc(18px + env(safe-area-inset-bottom))}.foot-in{max-width:640px;margin:0 auto;display:flex;align-items:center;gap:14px;flex-wrap:wrap}.foot-in .btn{margin-left:auto;min-width:160px}.foot-in .btn.ghost{margin-left:0}@media(max-width:560px){.foot-in .btn{flex:1 1 0;min-width:0;margin-left:0}.foot-in>:not(.btn){flex:1 1 100%}}.foot.ok,.foot.bad{border-top-color:transparent;animation:rise .22s ease-out}.foot.ok{background:var(--good-soft)}.foot.bad{background:var(--bad-soft)}@keyframes rise{0%{transform:translateY(100%)}}.verdict{display:flex;align-items:center;gap:14px}.verdict .badge{width:52px;height:52px;background:var(--card);box-shadow:none}.foot.ok .verdict .badge{color:var(--good)}.foot.bad .verdict .badge{color:var(--bad)}.verdict strong{display:block;font-size:22px;font-weight:900;line-height:1.2}.verdict span{font-weight:800}.foot.ok .verdict{color:var(--good-ink)}.foot.bad .verdict{color:var(--bad-ink)}.steps{list-style:none;counter-reset:step;margin:0;padding:0;display:grid;gap:6px}.steps li{counter-increment:step;display:grid;grid-template-columns:28px 1fr;gap:10px;align-items:start;padding:8px 10px;border-radius:12px;font-size:16px}.steps li:before{content:counter(step);width:26px;height:26px;border-radius:50%;display:grid;place-items:center;font-size:13px;font-weight:900;background:var(--off);color:var(--muted)}.steps li.bug{background:var(--bad-soft);color:var(--bad-ink);font-weight:800}.steps li.bug:before{background:var(--bad);color:#fff}.steps li.fix{background:var(--good-soft);color:var(--good-ink);font-weight:800}.steps li.fix:before{background:var(--good);color:#fff}.compare{display:grid;grid-template-columns:1fr 1fr;gap:14px}@media(max-width:600px){.compare{grid-template-columns:1fr}}.compare>div{border:2px solid var(--line);border-radius:18px;padding:14px 10px 10px}.compare h3{display:flex;align-items:center;gap:8px;font-size:15px;font-weight:900;margin:0 6px 10px}.compare h3 i{width:12px;height:12px;border-radius:50%;background:var(--bad)}.compare>div+div h3 i{background:var(--good)}details{margin-top:12px}summary{cursor:pointer;font-weight:900;color:var(--sky);list-style:none}summary::-webkit-details-marker{display:none}summary:before{content:"▸";display:inline-block;width:1em;transition:transform .15s}details[open]>summary:before{transform:rotate(90deg)}details[open]>summary{margin-bottom:10px}.match{font-weight:900;color:var(--bad-ink);margin-top:12px}.worked{border:2px solid var(--line);border-radius:20px;padding:14px 12px}details.miss{border:2px solid var(--line);border-radius:18px;padding:12px 16px;margin:0 0 10px}details.miss summary{color:var(--ink);font-weight:800}details.miss .why{display:block;margin-left:1em;color:var(--bad-ink);font-weight:800;font-size:14px}.answers{list-style:none;margin:0;padding:0;display:grid;gap:8px}.answers li{display:grid;grid-template-columns:1fr auto 30px;gap:12px;align-items:center;padding:10px 14px;border-radius:14px;background:color-mix(in srgb,var(--off) 45%,transparent);font-variant-numeric:tabular-nums;font-weight:800}.answers small{color:var(--muted);font-weight:700}.answers .mark{width:28px;height:28px;border-radius:50%;display:grid;place-items:center;color:#fff;background:var(--good)}.answers .mark svg{width:16px;height:16px}.answers li.wrong .mark{background:var(--bad)}.answers li.wrong .you{color:var(--bad-ink)}.picker .tile .badge{width:36px;height:36px;font-weight:900;font-size:15px}.truth{margin-bottom:20px}.confetti{position:fixed;top:0;right:0;bottom:0;left:0;pointer-events:none;overflow:hidden;z-index:20}.confetti i{position:absolute;top:-20px;width:10px;height:14px;border-radius:3px;animation:fall 2.4s cubic-bezier(.25,.6,.5,1) forwards}@keyframes fall{to{transform:translateY(105vh) rotate(720deg);opacity:.4}}@media(prefers-reduced-motion:reduce){.confetti{display:none}}.engine{margin-top:24px;border:2px dashed var(--line);border-radius:20px;padding:18px;font-size:14px}.engine h3{font-size:12px;text-transform:uppercase;letter-spacing:.08em;color:var(--muted);margin:0 0 8px}.engine h3:not(:first-child){margin-top:20px}.engine p{color:var(--muted);margin:0 0 10px}.engine ul{list-style:none;margin:0;padding:0}.bars li{display:grid;grid-template-columns:minmax(0,1fr) 64px 36px;gap:8px;align-items:center;padding:3px 0}.bars .n{overflow:hidden;text-overflow:ellipsis;white-space:nowrap;font-weight:800}.bars .b{height:8px;border-radius:4px;background:var(--off);overflow:hidden}.bars .b b{display:block;height:100%;background:var(--ember);transition:width .4s}.bars .p{text-align:right;font-variant-numeric:tabular-nums;color:var(--muted)}.groups li{display:grid;grid-template-columns:auto minmax(0,1fr) auto;gap:10px;padding:6px 0;border-top:1px solid var(--line);align-items:baseline}.groups em{font-style:normal;color:var(--muted)}.tags{display:flex;flex-wrap:wrap;gap:6px;margin-top:10px}.tags span{background:var(--off);border-radius:999px;padding:2px 10px;font-size:13px;font-weight:800}.engine-toggle{color:var(--muted)}