:root{--bg:#faf6ee;--card:#fffdf8;--ink:#1a1612;--muted:#5a5045;--line:#e3d9c6;--acc:#f08a61;--acc2:#b83c0c;--on:#1a1612;--yel:#ffc93c;--soft:#f3ebdb;--bad:#b42318;--code:#f3ebdb;--codeink:#1a1612;--field:#8c8272;--r:14px;--tab:58px;font-family:Inter,ui-sans-serif,-apple-system,BlinkMacSystemFont,"Segoe UI",sans-serif;color:var(--ink);background:var(--bg);font-size:15px;line-height:1.35}
*{box-sizing:border-box;-webkit-tap-highlight-color:transparent}html,body{margin:0;min-height:100%;overscroll-behavior-y:none}body{padding:env(safe-area-inset-top) 0 0}
button,input,textarea{font:inherit;color:inherit}button{touch-action:manipulation;cursor:pointer}
h1,h2,h3,p{margin:0}h1{font-size:22px;letter-spacing:-.01em}h2{font-size:17px}.mut{color:var(--muted);font-size:13px}
#app{max-width:520px;margin:0 auto;min-height:100dvh;position:relative}
.top{display:flex;align-items:center;justify-content:space-between;height:48px;padding:0 16px}.brand{text-decoration:none;font-weight:800;color:var(--acc2);letter-spacing:-.01em}
.chip{display:inline-flex;align-items:center;gap:6px;height:30px;padding:0 11px;border-radius:99px;background:var(--yel);color:var(--on);font-size:13px;font-weight:600;border:0}
main{padding:4px 16px calc(var(--tab) + 20px + env(safe-area-inset-bottom))}
.tabs{position:fixed;left:0;right:0;bottom:0;z-index:5;display:flex;justify-content:center;background:var(--card);border-top:1px solid var(--line);padding-bottom:env(safe-area-inset-bottom)}
.tabs nav{display:flex;width:100%;max-width:520px}.tabs a{flex:1;height:var(--tab);display:flex;flex-direction:column;align-items:center;justify-content:center;gap:2px;font-size:12px;color:var(--muted);text-decoration:none;font-weight:600}
.tabs a svg{width:22px;height:22px;stroke:currentColor;fill:none;stroke-width:1.8;stroke-linecap:round;stroke-linejoin:round}.tabs a[aria-current=page]{color:var(--ink)}.tabs a[aria-current=page] svg{stroke:var(--acc2);stroke-width:2.4}
.card{background:var(--card);border:1px solid var(--line);border-radius:var(--r);padding:14px}.stack{display:grid;gap:12px}
.btn{text-decoration:none;display:flex;align-items:center;justify-content:center;gap:8px;width:100%;height:50px;border-radius:12px;border:1px solid #cf6743;background:var(--acc);color:var(--on);font-weight:700;transition:transform .12s,background .15s}.btn:active{transform:scale(.98);background:#f07a4a}
.btn.alt{background:var(--card);color:var(--ink)}.btn:disabled{opacity:.5}.btn.small{height:40px;font-size:14px}
.row{display:flex;align-items:center;gap:12px}.grow{flex:1;min-width:0}.right{margin-left:auto}
.hero{display:flex;align-items:center;gap:16px}.ring{position:relative;width:104px;height:104px;flex:none}.ring svg{transform:rotate(-90deg)}.ring circle{fill:none;stroke-width:9}.ring .bg{stroke:var(--soft)}.ring .fg{stroke:var(--acc);stroke-linecap:round;transition:stroke-dashoffset .6s ease}
.ring b{position:absolute;inset:0;display:flex;flex-direction:column;align-items:center;justify-content:center;font-size:22px;line-height:1}.ring b small{font-size:11px;color:var(--muted);font-weight:500;margin-top:3px}
.stat{display:flex;gap:18px;margin-top:8px}.stat div{display:grid}.stat b{font-size:18px}.stat span{font-size:12px;color:var(--muted)}
.bar{height:7px;border-radius:9px;background:var(--soft);overflow:hidden}.bar i{display:block;height:100%;background:var(--acc);border-radius:9px;transition:width .5s}
.week{display:flex;justify-content:space-between;gap:6px}.week div{flex:1;display:grid;justify-items:center;gap:5px;font-size:11px;color:var(--muted)}.week i{width:100%;max-width:34px;aspect-ratio:1;border-radius:10px;background:var(--soft)}.week i.on{background:var(--acc)}.week i.part{background:#f6b48f}.week .t{color:var(--ink);font-weight:700}
.cont{display:grid;gap:10px}.cont .tag{width:44px;height:44px;border-radius:12px;background:var(--acc);color:var(--on);display:grid;place-items:center;font-weight:800;font-size:14px;flex:none}
.chips{display:flex;gap:8px;overflow-x:auto;padding:2px 0 6px;scrollbar-width:none}.chips::-webkit-scrollbar{display:none}.chips button{flex:none;height:36px;padding:0 13px;border-radius:99px;border:1px solid var(--line);background:#fff;font-weight:600;font-size:13px}.chips button[aria-pressed=true]{background:var(--ink);border-color:var(--ink);color:#fff}
.path{display:grid;gap:8px}.step{display:flex;align-items:center;gap:12px;min-height:54px;padding:8px 12px;border-radius:12px;border:1px solid var(--line);background:#fff;text-align:left;width:100%}.step .n{width:32px;height:32px;border-radius:50%;display:grid;place-items:center;background:var(--soft);font-weight:700;font-size:13px;color:var(--acc2);flex:none}
.step.done .n{background:var(--acc);color:var(--on)}.step.cur{border:2px solid var(--ink);background:var(--yel)}.step.cur small{color:var(--on)}.step.cur .go{color:var(--on)}.step.lock{opacity:.45}.step small{display:block;color:var(--muted);font-size:12px}.step .go{margin-left:auto;color:var(--acc2);font-weight:700;font-size:13px}
.grid{display:grid;grid-template-columns:repeat(2,1fr);gap:10px}.pick{display:flex;gap:10px;align-items:center;min-height:62px;padding:10px 12px;border:1.5px solid var(--line);border-radius:12px;background:#fff;text-align:left}.pick[aria-pressed=true]{border-color:var(--acc);background:var(--soft)}.pick .tag{width:34px;height:34px;border-radius:9px;background:var(--acc);color:var(--on);display:grid;place-items:center;font-size:12px;font-weight:800;flex:none}.pick b{display:block;font-size:14px}.pick small{color:var(--muted);font-size:11px;display:block}
.field{display:grid;gap:5px;font-size:13px;font-weight:600}.field input{height:48px;border-radius:12px;border:1.5px solid var(--field);padding:0 12px;background:#fff;font-size:16px;font-weight:400}.field input:focus{outline:2px solid var(--acc);border-color:var(--acc)}
.err{color:var(--bad);font-size:13px;min-height:18px}.seg{display:flex;gap:8px}.seg button{flex:1;height:44px;border-radius:12px;border:1.5px solid var(--line);background:#fff;font-weight:650}.seg button[aria-pressed=true]{border-color:var(--acc);background:var(--soft);color:var(--acc2)}
.lesson{position:fixed;inset:0;z-index:20;background:var(--bg);display:flex;flex-direction:column;max-width:520px;margin:0 auto}.lh{display:flex;align-items:center;gap:12px;padding:calc(10px + env(safe-area-inset-top)) 14px 8px}.x{width:40px;height:40px;border-radius:12px;border:0;background:var(--soft);font-size:20px;line-height:1;color:var(--acc2)}
.lb{flex:1;overflow:auto;padding:6px 16px 16px;display:grid;align-content:start;gap:12px}.lt{font-size:13px;color:var(--muted)}
.explain{font-size:15px}.codebox{position:relative;background:var(--code);color:var(--codeink);border:1px solid var(--line);border-radius:14px;padding:14px;font:15px/1.65 ui-monospace,SFMono-Regular,Menlo,Consolas,monospace;white-space:pre-wrap;word-break:break-all;min-height:96px}
.codebox .c{opacity:1;color:#6b6054}.codebox .ok{opacity:1;color:var(--ink);font-weight:700}.codebox .bad{opacity:1;color:#fff;background:var(--bad);border-radius:3px}.codebox .cur{opacity:1;color:var(--ink);border-bottom:3px solid var(--acc)}.codebox .nl{opacity:.5}

.codebox textarea{position:absolute;inset:0;width:100%;height:100%;opacity:0;resize:none;border:0;font-size:16px;caret-color:transparent}
.tap{position:absolute;inset:auto 10px 8px auto;font-size:11px;color:#6b6054;pointer-events:none}
.live{display:flex;gap:16px;font-size:13px;color:var(--muted)}.live b{color:var(--ink)}
.wbox{width:100%;min-height:120px;border-radius:14px;border:1.5px solid var(--field);padding:12px;background:#fff;font:15px/1.5 ui-monospace,SFMono-Regular,Menlo,monospace;resize:none}.wbox:focus{outline:2px solid var(--acc)}
.sym{position:fixed;left:0;right:0;z-index:25;display:flex;gap:6px;overflow-x:auto;padding:7px 10px;background:#efe6d3;border-top:1px solid var(--line);max-width:520px;margin:0 auto;scrollbar-width:none}.sym::-webkit-scrollbar{display:none}
.sym button{flex:none;min-width:40px;height:40px;border-radius:9px;border:1px solid #a89c85;background:#fff;font:600 17px ui-monospace,Menlo,monospace;padding:0 8px}.sym button:active{background:var(--soft)}
.sheet{border-top:2px solid var(--ink);position:fixed;left:0;right:0;bottom:0;z-index:30;max-width:520px;margin:0 auto;background:#fff;border-radius:20px 20px 0 0;border:1px solid var(--line);padding:18px 16px calc(16px + env(safe-area-inset-bottom));display:grid;gap:12px;animation:up .25s ease;}
@keyframes up{from{transform:translateY(30px);opacity:0}}.sheet .big{font-size:30px;font-weight:800;color:var(--acc2)}.sheet .res{display:flex;gap:18px}.sheet .res div{display:grid}.sheet .res b{font-size:18px}.sheet .res span{font-size:12px;color:var(--muted)}
.auth{padding:28px 18px;display:grid;gap:18px}.auth .logo{font-weight:800;font-size:24px;color:var(--acc2)}.tags{display:flex;flex-wrap:wrap;gap:6px}.tags span{padding:5px 10px;border-radius:99px;background:var(--yel);color:var(--on);font-size:12px;font-weight:650}
.preview{background:var(--code);color:var(--codeink);border:1px solid var(--line);border-radius:14px;padding:14px;font:14px/1.6 ui-monospace,Menlo,monospace}.preview em{font-style:normal;color:var(--acc2);font-weight:700}
#toast{position:fixed;left:50%;bottom:calc(var(--tab) + 18px);transform:translate(-50%,20px);background:var(--ink);color:#fff;padding:10px 14px;border-radius:10px;font-size:13px;opacity:0;pointer-events:none;transition:.25s;z-index:60}#toast.on{opacity:1;transform:translate(-50%,0)}
.skel{height:90px;border-radius:14px;background:var(--soft);animation:sk 1.2s infinite alternate}@keyframes sk{to{opacity:.5}}
a{color:var(--acc2)}a:focus-visible,button:focus-visible{outline:3px solid var(--ink);outline-offset:2px}
@media(prefers-reduced-motion:reduce){*{animation:none!important;transition:none!important}}
@media(min-width:700px){#app{padding-top:10px}.tabs{left:50%;right:auto;transform:translateX(-50%);width:520px;border:1px solid var(--line);border-radius:16px 16px 0 0}}

.newcard{background:var(--soft,#f3ebdb);border:1.5px solid #1a1612;border-radius:12px;padding:10px 12px;margin:0 0 10px}
.newcard .nt{display:inline-block;background:#ffc93c;color:#1a1612;font-weight:700;font-size:12px;padding:2px 8px;border-radius:99px}
.newcard p{margin:6px 0 4px;font-size:15px;line-height:1.35}
.newcard .dots{display:flex;gap:6px}.newcard .dots i{width:22px;height:6px;border-radius:3px;background:#d9cdb5}.newcard .dots i.on{background:#e8501a}
.newcard p{font-size:14px;margin:4px 0 0}.newcard b{font-family:ui-monospace,Menlo,monospace;background:#fffdf8;border:1px solid #d9cdb5;border-radius:6px;padding:0 5px}

.prac{text-decoration:none;color:var(--ink);align-items:center;min-height:56px}
.plist{display:grid;gap:8px}.prow{display:flex;align-items:center;gap:10px;text-decoration:none;color:var(--ink);padding:12px;font-size:14px}.prow.locked{opacity:1;background:var(--soft)}.prow.solved{background:var(--soft)}
.pd{font-size:11px;font-weight:700;text-transform:uppercase;padding:2px 8px;border-radius:99px;border:1.5px solid var(--ink);flex:none}.pd.easy{background:#fffdf8}.pd.medium{background:var(--yel)}.pd.hard{background:var(--acc)}

.sr-only{position:absolute;width:1px;height:1px;padding:0;margin:-1px;overflow:hidden;clip:rect(0,0,0,0);white-space:nowrap;border:0}

.context{font-size:13px;line-height:1.4;border-left:3px solid var(--field);padding:4px 9px;margin:6px 0 10px;color:var(--muted)}
/* Responsive workspace: phone stays compact; desktop uses a real app shell. */
.desk-rail{display:none}.view-title{position:absolute;width:1px;height:1px;overflow:hidden;clip:rect(0,0,0,0);white-space:nowrap}
#content[data-view="me"]{min-width:0}#content[data-view="me"]>.stack{min-width:0}
#content[data-view="me"] .chips{flex-wrap:wrap;overflow:visible;gap:7px}
#content[data-view="me"] .chips button{height:40px}
#content[data-view="me"] .field input{width:100%;min-width:0}
#content[data-view="me"] details{min-width:0}#content[data-view="me"] details>.stack{min-width:0}
#content[data-view="me"] summary{cursor:pointer;min-height:28px;list-style-position:inside}
#content[data-view="me"] .seg button{min-width:0}
@keyframes enterView{from{transform:translateY(9px)}to{transform:none}}
#content>.stack{animation:enterView .32s ease-out}.card,.step,.pick,.chips button,.prow{transition:border-color .18s,background-color .18s,transform .18s}
@media(hover:hover){.step:not(:disabled):hover,.pick:hover,.prac:hover,.prow:not(.locked):hover{border-color:var(--ink);transform:translateY(-2px)}.btn:hover{background:#f36b32}.btn.alt:hover{background:var(--soft)}.chips button:hover{border-color:var(--ink)}}
@media(min-width:1050px){
 #app{max-width:none;margin:0 0 0 218px;padding:0 272px 0 0;min-height:100dvh}
 .top{height:88px;padding:0 42px;border-bottom:1px solid var(--line)}.top .brand{font-size:23px}.top .chip{height:36px;font-size:14px}
 #content{padding:30px 36px 60px;min-width:0;max-width:1100px;margin:0 auto}
 .view-title{position:static;clip:auto;white-space:normal;width:auto;height:auto;overflow:visible;font-size:32px;letter-spacing:-1px;margin-bottom:24px;animation:enterView .3s ease}
 .tabs{left:0;top:0;bottom:0;right:auto;transform:none;width:218px;border:0;border-right:1px solid var(--line);border-radius:0;padding:124px 20px 28px;display:block;background:var(--card)}
 .tabs:before{content:'P /';position:absolute;top:29px;left:30px;font-size:28px;font-weight:900;color:var(--acc2);letter-spacing:-2px}
 .tabs:after{content:'LEARN. BUILD. REPEAT.';position:absolute;bottom:28px;left:28px;right:12px;font-size:10px;letter-spacing:.13em;color:var(--muted)}
 .tabs nav{display:grid;gap:8px;width:100%}.tabs a{flex-direction:row;justify-content:flex-start;height:50px;font-size:14px;gap:13px;padding:0 15px;border:1px solid transparent;border-radius:12px}.tabs a[aria-current=page]{background:var(--soft);border-color:var(--line)}
 .tabs a:hover{background:var(--soft)}.tabs a svg{width:21px;height:21px}
 .desk-rail{display:flex;position:fixed;right:0;top:0;bottom:0;width:272px;padding:38px 26px;border-left:1px solid var(--line);flex-direction:column;background:var(--soft);gap:24px}
 .rail-kicker{font-size:10px;font-weight:700;letter-spacing:.17em;color:var(--acc2)}.desk-rail h2{font-size:24px;line-height:1.2;letter-spacing:-.6px}
 .rail-code{font:14px/2.2 ui-monospace,monospace;border-top:1px solid var(--field);border-bottom:1px solid var(--field);padding:20px 0}.rail-code span{color:var(--muted);margin-right:14px;font-size:11px}
 .rail-metric{display:flex;align-items:baseline;gap:10px}.rail-metric b{font-size:58px;line-height:1}.rail-metric span{font-size:13px;color:var(--muted)}
 .rail-progress{display:grid;gap:12px;font-size:12px}.rail-progress .bar{background:var(--card)}.rail-link{margin-top:auto;font-weight:700;text-decoration:none;font-size:13px}.desk-rail>p{font-size:11px;color:var(--muted)}
 .card{padding:22px;border-radius:18px}.stack{gap:18px}
 #content[data-view="home"]>.stack{grid-template-columns:1fr 1fr}
 #content[data-view="home"] .hero{grid-column:1/-1;min-height:190px;gap:28px}.hero h2{font-size:26px}.hero .mut{font-size:14px}.hero .stat{gap:38px;margin-top:18px}.hero .stat b{font-size:24px}
 #content[data-view="home"] .cont{grid-column:1/-1;grid-template-columns:1fr auto;align-items:center;min-height:120px}.cont .btn{min-width:170px}.cont .tag{width:52px;height:52px}.cont b{font-size:19px}
 #content[data-view="home"] .prac{min-height:160px;align-items:flex-start}#content[data-view="home"] .prac b{font-size:21px}#content[data-view="home"] .prac .mut{margin-top:7px}
 #content[data-view="learn"] .chips{flex-wrap:wrap;overflow:visible}#content[data-view="learn"] .path{grid-template-columns:1fr 1fr;gap:10px}.step{min-height:72px}
 #content[data-view="learn"]>.stack>.row{margin-top:12px}
 #content[data-view="practice"] .plist{grid-template-columns:1fr 1fr}.prow{flex-wrap:wrap;min-height:170px;align-content:start}.prow .grow{flex:1 0 100%;order:2}.prow>.mut{margin-left:auto}.prow .pd{margin-bottom:8px}
 #content[data-view="me"]>.stack{grid-template-columns:1fr 1fr;align-items:start}#content[data-view="me"]>.stack>section:first-child{grid-column:1/-1;min-height:110px}#content[data-view="me"] #out{grid-column:1;align-self:end}#content[data-view="me"]>.stack>p{grid-column:1/-1}
 .auth{max-width:560px;margin:0 auto;padding:64px 24px}#app:has(>.auth){margin:0 auto;padding:0;max-width:900px}
 .lesson{max-width:none;margin:0;left:218px;right:0;padding:0 54px 38px}.lh{padding:28px 0 24px;max-width:1200px;width:100%;margin:0 auto}.lh .bar{height:9px}.lb{max-width:1200px;width:100%;margin:0 auto;padding:18px 0 90px;grid-template-columns:minmax(250px,.8fr) minmax(400px,1.5fr);gap:18px 36px}
 .lt{grid-column:1/-1;font-size:15px;padding-bottom:12px;border-bottom:1px solid var(--line)}.context{grid-column:1;margin:0}.newcard{grid-column:1;grid-row:3;padding:20px}.newcard p{font-size:15px;line-height:1.6;margin-top:9px}.explain{grid-column:1;font-size:18px;line-height:1.5}.codebox{grid-column:2;grid-row:2/6;min-height:320px;font-size:21px;line-height:1.9;padding:32px;border-radius:20px;word-break:normal;overflow-wrap:anywhere;align-self:start}.live{grid-column:2;align-self:start;font-size:14px;gap:30px}.wbox{grid-column:2;grid-row:2/6;min-height:360px;padding:24px;font-size:18px}.lb>.err,.lb>#chk{grid-column:2}.sym{left:218px;right:0;max-width:none;justify-content:center;padding:12px}.sheet{left:calc(218px + (100vw - 218px - 640px)/2);right:auto;width:640px;max-width:640px;padding:28px;border-radius:24px 24px 0 0}
}
@media(min-width:1050px) and (max-width:1279px){#app{padding-right:0}.desk-rail{display:none}#content{max-width:900px}.lb{grid-template-columns:minmax(200px,.8fr) minmax(350px,1.5fr)}}
@media(prefers-reduced-motion:reduce){*,*:before,*:after{animation:none!important;transition:none!important;scroll-behavior:auto!important}.card:hover,.step:hover,.pick:hover,.prow:hover{transform:none!important}}
@media(min-width:1050px){#app:has(>.lesson){margin:0;padding:0}.lesson{left:0;padding-left:6vw;padding-right:6vw}.sym{left:0}.sheet{left:calc((100vw - 640px)/2)}}
@media(min-width:1050px){.lb:not(:has(.lt)) .wbox{grid-row:1/5}.lb:not(:has(.lt))>.explain{grid-row:1}.lb:not(:has(.lt))>#fb{grid-row:5}}
body.motion-off *,body.motion-off *:before,body.motion-off *:after{animation:none!important;transition:none!important}.motion-off .code-mesh span{translate:none}.motion-off .rv{opacity:1!important;transform:none!important}
.motion-toggle{background:transparent;border:1px solid var(--field);border-radius:20px;padding:8px 12px;font:inherit;color:var(--muted);font-size:12px;cursor:pointer}

.code-example{margin:12px 0 16px}.code-example summary{padding:10px 0;cursor:pointer}.code-example pre{white-space:pre-wrap;overflow-wrap:anywhere;padding:12px;background:var(--soft);border:1px solid var(--line);border-radius:10px;font:14px/1.6 ui-monospace,monospace}
.practice-level summary{cursor:pointer;display:flex;flex-direction:column;gap:5px;list-style-position:inside}.practice-level[open] summary{margin-bottom:18px}.practice-level .prow{border-top:1px solid var(--line,#ded5c6);padding:16px 0;gap:14px;text-decoration:none;color:inherit}.practice-level .locked{opacity:.45}.practice-number{font:600 13px monospace;min-width:25px}.practice-expected{padding:16px 20px;background:#f3ecdf;border-left:3px solid #e65c1b;margin:18px 0}.practice-expected pre{margin:8px 0 0;white-space:pre-wrap;overflow-wrap:anywhere;font:14px/1.6 monospace}.practice-session .lh{flex-wrap:wrap}.practice-session .lh .grow{min-width:130px}.practice-session .lb{padding-bottom:40px}.practice-context{white-space:pre-wrap}.practice-session #wb{min-height:220px}.practice-session .err{min-height:24px}.practice-session #lesson-output{white-space:pre-wrap;overflow-wrap:anywhere}@media(max-width:420px){.practice-level .prow{align-items:flex-start}.practice-level .prow .mut{font-size:11px}.practice-session .lh{gap:10px}.practice-session .lh .mut{font-size:11px}}
.practice-level .plist{display:flex;flex-direction:column;gap:0}.practice-level .prow{display:flex;min-height:80px;background:transparent;opacity:1}.practice-level .prow.locked{color:#796f62}.practice-level .prow .grow{min-width:0}.practice-level summary .mut{display:block}.practice-session #skip{width:auto;min-width:78px;margin-left:auto}