:root{font-family:'Instrument Sans',Inter,system-ui,-apple-system,BlinkMacSystemFont,'Segoe UI',sans-serif;color:#17191c;background:#f3f4f4;font-synthesis:none;--green:#197a61;--light:#ddf1ea;--line:#dde0e2;--muted:#5c6166}*{box-sizing:border-box}body{margin:0}button,input,textarea,select{font:inherit}button,a,input,textarea,select{-webkit-tap-highlight-color:transparent}button,.button{min-height:46px;border:1px solid var(--line);border-radius:10px;background:#fff;color:inherit;padding:10px 17px;font-size:14px;font-weight:550;cursor:pointer;text-decoration:none;display:inline-flex;align-items:center;justify-content:center;gap:8px}button:hover,.button:hover{border-color:#8d9692;background:#f8faf9}button:disabled{opacity:.48;cursor:not-allowed}button:focus-visible,a:focus-visible,input:focus-visible,select:focus-visible,textarea:focus-visible{outline:3px solid #75b5a4;outline-offset:3px}.primary{background:var(--green);border-color:var(--green);color:white}.primary:hover{background:#14634f}.dark{background:#17191c;color:white;border-color:#17191c}.dark:hover{background:#303539}.quiet{border-color:transparent;background:transparent}.danger{color:#b3261e}.muted,small{color:var(--muted)}small{font-size:12px;line-height:1.5}.eyebrow{text-transform:uppercase;letter-spacing:.08em;font-size:11px;font-weight:650;color:var(--muted)}h1,h2,h3,p{margin-top:0}h1{font-size:25px;letter-spacing:-.035em;line-height:1.25}h2{font-size:17px;letter-spacing:-.02em}h3{font-size:15px}p{line-height:1.6}header{background:white;border-bottom:1px solid var(--line);padding:16px 28px;display:flex;align-items:center;gap:24px;min-height:80px}.brand{display:flex;align-items:center;gap:12px;min-width:0}.brand-mark{width:38px;height:38px;border-radius:10px;display:grid;place-items:center;background:#17191c;color:white;font-weight:700;flex-shrink:0}.brand strong{font-size:15px;display:block}.brand small{display:block}.spacer{flex:1}.head-actions{display:flex;align-items:center;gap:9px}.badge{display:inline-flex;align-items:center;gap:7px;border-radius:99px;background:var(--light);color:var(--green);font-size:12px;font-weight:600;padding:8px 12px;white-space:normal;line-height:1.4}.badge.amber{background:#fff1d6;color:#8a5a00}.badge.neutral{background:#f3f4f4;color:var(--muted)}.card{background:white;border:1px solid var(--line);border-radius:12px;padding:24px}.card h2:last-child{margin-bottom:0}.row{display:flex;align-items:center;gap:12px}.stack{display:grid;gap:16px}.grid2{display:grid;grid-template-columns:1fr 1fr;gap:14px}.full{width:100%}.page{max-width:1280px;padding:30px;margin:auto}.section-head{display:flex;align-items:center;justify-content:space-between;gap:16px;margin-bottom:20px}.section-head h1,.section-head h2{margin:0}.loading{text-align:center;padding:100px 20px}.empty{text-align:center;padding:48px 20px}.empty p{color:var(--muted);max-width:45ch;margin:12px auto 24px}nav{display:flex;gap:4px}nav button.active{background:#f3f4f4;border-color:transparent}nav button{background:transparent;border-color:transparent}label{font-size:13px;font-weight:550;display:grid;gap:8px}input,textarea,select{width:100%;border:1px solid var(--line);border-radius:9px;padding:13px;background:white;color:inherit;min-width:0}textarea{resize:vertical;min-height:95px}input[type=file]{font-size:14px}form{display:grid;gap:16px}.login{max-width:420px;margin:12vh auto;padding:0 18px}.login .brand{margin-bottom:34px}.login h1{font-size:31px}.login .card{padding:30px}.login .legal{margin-top:18px;font-size:12px;color:var(--muted);line-height:1.6}.login button{margin-top:6px}.login label{font-size:14px}#notice{position:fixed;z-index:20;left:50%;transform:translateX(-50%);top:16px;border-radius:10px;background:#17191c;color:white;padding:12px 20px;max-width:calc(100vw - 32px);box-shadow:0 8px 25px #0002;font-size:14px;display:none}#notice.visible{display:block}#notice.error{background:#9b241f}.progress{display:flex;gap:5px;flex:1;max-width:370px}.progress span{height:6px;background:var(--line);border-radius:20px;flex:1}.progress .done{background:var(--green)}.progress .current{background:#17191c}.lesson-shell{display:grid;grid-template-columns:minmax(0,1fr) 340px;min-height:calc(100vh - 81px)}.lesson-main{max-width:810px;width:100%;margin:auto;padding:38px}.question-meta{font-size:13px;color:var(--muted);display:flex;justify-content:space-between;gap:12px;margin-bottom:18px}.question{font-size:23px;line-height:1.55;font-weight:500;letter-spacing:-.02em;margin:0}.question-card{padding:30px}.ratio{display:grid;gap:12px;margin-top:25px;padding-top:24px;border-top:1px solid var(--line)}.ratio-line{display:flex;align-items:center;gap:6px;font-size:12px;color:var(--muted)}.ratio-line span{width:58px}.ratio-line i{height:20px;width:42px;border-radius:4px;background:var(--light);border:1px solid #9ccabd}.ratio-line:nth-child(2) i{background:#e9ebec;border-color:#bdc4c7}.options{display:grid;grid-template-columns:1fr 1fr;gap:12px;margin-top:18px}.option{justify-content:flex-start;min-height:66px;font-size:19px;padding:14px 18px;text-align:left}.option b{font-size:13px;border-radius:8px;background:#f3f4f4;width:31px;height:31px;display:grid;place-items:center}.option.selected{outline:2px solid #17191c;outline-offset:-2px}.option.selected b{background:#17191c;color:white}.answer-input{font-size:22px;margin-top:20px;height:62px}.lesson-actions{display:flex;gap:10px;flex-wrap:wrap;margin-top:20px}.submit{margin-left:auto;min-width:150px}.hint{padding:16px;background:var(--light);border-radius:9px;margin-top:18px;font-size:14px;line-height:1.6}.hint b{display:block;color:var(--green);margin-bottom:4px}.feedback{padding:18px;margin-top:18px;border-radius:10px;background:var(--light);line-height:1.6}.feedback.wrong{background:#fff1d6;color:#8a5a00}.feedback strong{display:block}.feedback button{margin-top:10px}.helper{background:#fff;border-left:1px solid var(--line);display:flex;flex-direction:column;min-width:0}.helper-title{font-weight:600;padding:20px;border-bottom:1px solid var(--line);font-size:15px;display:flex;align-items:center;justify-content:space-between}.helper-content{padding:20px;display:grid;gap:14px;align-content:start;flex:1}.bubble{background:#f3f4f4;border-radius:10px;padding:14px;line-height:1.6;font-size:14px;overflow-wrap:anywhere}.helper-footer{padding:20px;border-top:1px solid var(--line);font-size:12px;line-height:1.6;color:var(--muted)}.mobile-helper,.helper-close{display:none}.intro{max-width:680px;margin:50px auto}.intro h1{font-size:32px}.intro .card{padding:34px}.intro p{color:var(--muted)}.intro .topics{display:flex;gap:8px;flex-wrap:wrap;margin:24px 0}.dashboard{display:grid;grid-template-columns:minmax(0,2fr) minmax(280px,1fr);gap:20px}.stats{display:grid;grid-template-columns:repeat(3,1fr);gap:14px;margin-bottom:20px}.stat{padding:22px}.stat .number{display:block;font-size:32px;font-weight:600;letter-spacing:-.04em;margin:10px 0 4px}.bar{height:7px;border-radius:20px;background:#dde0e2;overflow:hidden;margin:14px 0 9px;display:flex}.bar span{background:var(--green);height:100%}.topic-list{padding:0;overflow:hidden}.topic-list h2{padding:22px;margin:0;border-bottom:1px solid var(--line)}.topic-row{padding:20px 22px;border-bottom:1px solid var(--line);display:grid;grid-template-columns:1fr auto;gap:6px 18px}.topic-row:last-child{border:0}.topic-row h3{margin:0}.topic-row .bar{max-width:300px}.topic-row button{grid-column:2;grid-row:1/4}.detail-top{margin-bottom:24px;display:flex;align-items:center;gap:14px}.detail-top h1{margin:0}.question-row{padding:18px;border-top:1px solid var(--line);display:grid;grid-template-columns:36px 1fr;gap:14px;line-height:1.5}.question-number{width:34px;height:34px;background:var(--light);color:var(--green);border-radius:9px;display:grid;place-items:center;font-weight:600}.resource{display:flex;align-items:center;gap:14px;padding:19px 0;border-bottom:1px solid var(--line)}.resource:last-child{border-bottom:0}.resource-icon{width:44px;height:52px;border-radius:8px;background:#f3f4f4;display:grid;place-items:center;font-size:11px;font-weight:600;flex-shrink:0}.resource-main{flex:1;min-width:0}.resource-main strong{display:block;font-size:14px;overflow-wrap:anywhere;margin-bottom:5px}.upload{border:1px dashed #a1a6ab;border-radius:10px;padding:23px;text-align:center;background:#fafbfb;margin-bottom:18px}.upload label{font-size:16px}.upload input{background:white;margin-top:8px}.note{font-size:13px;color:var(--muted);line-height:1.6;margin:14px 0}.review{max-width:750px}.review .card{margin-bottom:20px}.settings{max-width:650px}.error-box{color:#b3261e;background:#fbe9e7;padding:12px;border-radius:8px;font-size:14px}.hidden{display:none!important}.period{width:auto;max-width:200px}.pending{color:#8a5a00}.footer-note{font-size:12px;color:var(--muted);margin-top:22px;line-height:1.5}
@media(min-width:1400px){.lesson-main{padding:50px}.lesson-shell{grid-template-columns:minmax(0,1fr) 380px}}
@media(max-width:1000px){header{gap:16px;padding:16px 20px}.lesson-shell{grid-template-columns:minmax(0,1fr) 290px}.lesson-main{padding:24px}.question{font-size:20px}.dashboard{grid-template-columns:1fr}.dashboard-aside{display:grid;grid-template-columns:1fr 1fr;gap:18px;align-items:start}.page{padding:24px}.stats{margin-bottom:18px}}
@media(max-width:720px){header{padding:14px 16px;flex-wrap:wrap;gap:12px}.brand{flex:1}.brand strong{font-size:14px}.head-actions{gap:4px}.head-actions .badge{display:none}header nav{order:3;width:100%;border-top:1px solid var(--line);padding-top:10px}header nav button{flex:1}.progress{order:3;max-width:none;flex-basis:100%}.lesson-shell{display:block;min-height:auto}.lesson-main{padding:20px 16px 90px}.question-card{padding:22px 18px}.question{font-size:20px}.question-meta{font-size:12px}.options{gap:10px}.option{min-height:60px;padding:12px 14px}.lesson-actions{gap:8px}.lesson-actions>button:not(.submit){flex:1}.submit{width:100%;margin-top:4px;height:52px}.helper{display:none}.helper.open{display:flex;position:fixed;z-index:10;bottom:0;left:0;right:0;max-height:80dvh;border-radius:20px 20px 0 0;box-shadow:0 -8px 30px #0002;border:none}.helper-content{overflow-y:auto;flex:initial}.helper-close{display:inline-flex}.mobile-helper{display:flex;position:fixed;bottom:0;left:0;right:0;width:100%;border-radius:0;border-bottom:0;justify-content:space-between;padding:16px 20px;padding-bottom:max(16px,env(safe-area-inset-bottom));box-shadow:0 -2px 8px #0001}.page{padding:22px 16px}.stats{grid-template-columns:1fr 1fr;gap:10px}.stats .stat:last-child{grid-column:1/-1}.stat{padding:18px}.stat .number{font-size:29px}.dashboard-aside{grid-template-columns:1fr}.card{padding:20px}.topic-list{padding:0}.topic-row{padding:18px}.topic-row button{padding:8px 12px;min-height:44px}.section-head{align-items:start}.section-head h1{font-size:23px}.period{font-size:12px;max-width:125px;padding:10px}.intro{margin:25px auto}.intro .card{padding:25px}.intro h1{font-size:28px}.login{margin:7vh auto}.question-row{padding:16px;gap:10px}.resource{gap:10px}.resource button{padding:8px 12px}.detail-top h1{font-size:21px}.helper-footer{padding:14px 20px}.grid2{grid-template-columns:1fr}.review .row{flex-wrap:wrap}}
@media(prefers-reduced-motion:no-preference){button{transition:background .12s ease,border-color .12s ease}}

#tutor-history{display:grid;gap:12px;max-height:38vh;overflow:auto}.bubble p{white-space:pre-wrap;margin:8px 0 0}.student-message{background:var(--light)}.voice-actions{display:flex;flex-wrap:wrap;gap:8px}.voice-actions button{flex:1;font-size:12px;padding:8px}.source-text{white-space:pre-wrap;overflow-wrap:anywhere;font:inherit;max-height:350px;overflow:auto}.draft{border-top:1px solid var(--line);padding:18px 0;margin-top:18px}.draft p{margin:12px 0}.draft blockquote{margin:12px 0;padding-left:12px;border-left:3px solid var(--line);overflow-wrap:anywhere}.toggle{display:flex;align-items:center}.toggle input{width:auto}#voice-status{font-size:12px;color:var(--muted);margin:0}.helper-content form{gap:10px}.helper-content textarea{min-height:75px}

/* Separate account entrances. */
.portal-brand{display:flex;align-items:center;gap:12px;color:#17191c;text-decoration:none}.portal-brand>span:last-child{display:grid;gap:3px}.portal-brand strong{font-size:19px}.portal-brand small{font-size:12px;color:var(--muted)}.portal-brand .brand-mark{font-size:17px;flex-shrink:0}.login-links{display:flex;justify-content:space-between;gap:16px;margin-top:24px;font-size:13px}.login-links a{color:var(--green);text-underline-offset:4px}.login .button{margin:16px 0;text-align:center}