:root{--ink:#203b37;--muted:#727b72;--green:#244b47;--green2:#34655e;--paper:#f8f8f2;--white:#fff;--line:#e1e6dc;--lime:#e6ed9b;--lime2:#f2f5d7;--coral:#b05a3d;--shadow:0 12px 45px #233d3610;font-family:'Avenir Next','PingFang SC','Microsoft YaHei',sans-serif;color:var(--ink);background:var(--paper);font-size:15px;font-synthesis:none}*{box-sizing:border-box}body{margin:0}button,input,textarea,select{font:inherit}button,a,input,textarea,select{-webkit-tap-highlight-color:transparent}button{cursor:pointer}button{color:inherit}a{color:inherit}button:focus-visible,a:focus-visible,input:focus-visible,textarea:focus-visible,select:focus-visible,summary:focus-visible{outline:3px solid #a5b933;outline-offset:3px}button:disabled{opacity:.55;cursor:not-allowed}h1,h2,h3,p{margin:0}p{line-height:1.8}h1{font-size:40px;font-weight:600;letter-spacing:-1.5px;line-height:1.3}h2{font-size:24px;letter-spacing:-.6px;line-height:1.4}h3{font-size:18px;line-height:1.5}small,.small{font-size:12px;line-height:1.6}.muted{color:var(--muted)}.eyebrow{font-size:11px;letter-spacing:2px;text-transform:uppercase;font-weight:700}.serif{font-family:Georgia,'Songti SC',serif;font-style:italic}.shell{display:grid;grid-template-columns:248px minmax(0,1fr);min-height:100vh}.sidebar{position:sticky;top:0;height:100vh;overflow-y:auto;border-right:1px solid var(--line);padding:27px 20px;background:#f0f2e9;z-index:20}.brand{display:flex;gap:12px;align-items:center;margin-bottom:30px}.mark{display:grid;place-items:center;width:43px;height:43px;border-radius:13px;background:var(--green);color:var(--lime);font:bold italic 33px Georgia}.brand strong{font-size:18px;letter-spacing:-.4px}.brand small{display:block;color:var(--muted);font-size:10px;letter-spacing:1px;margin-top:3px}.nav{display:flex;flex-direction:column;gap:4px}.nav button,.week-link{border:0;background:transparent;width:100%;text-align:left;padding:11px 13px;border-radius:9px;display:flex;align-items:center;gap:11px;font-weight:500;font-size:13px}.nav button.active{background:var(--green);color:white}.nav button:hover:not(.active),.week-link:hover{background:#e6eadc}.nav-icon{width:20px;font-size:18px;display:inline-flex;justify-content:center}.nav-title{margin:28px 12px 10px;font-size:10px;letter-spacing:1.7px;color:var(--muted);display:flex;justify-content:space-between}.week-link{padding:8px 10px;font-size:12px;font-weight:400;gap:9px}.week-link.active{background:white;box-shadow:0 2px 8px #1a3d3610;font-weight:600}.week-num{width:25px;height:25px;flex-shrink:0;border:1px solid #dbe1d3;border-radius:50%;display:grid;place-items:center;font-size:10px}.week-link.active .week-num{background:var(--green);color:white;border-color:var(--green)}.week-label{overflow:hidden;text-overflow:ellipsis;white-space:nowrap}.tick{margin-left:auto;color:#47752c}.sidebar-footer{margin:24px 9px 0;border-top:1px solid var(--line);padding-top:15px}.topbar{height:83px;padding:0 45px;border-bottom:1px solid var(--line);display:flex;align-items:center;justify-content:space-between;gap:15px;background:#ffffff75}.breadcrumbs{font-size:12px;color:var(--muted)}.actions{display:flex;align-items:center;gap:12px}.language{display:flex;padding:3px;background:#e9ecdf;border-radius:7px}.language button{border:0;padding:6px 10px;border-radius:5px;font-size:11px;background:none}.language button.active{background:white;box-shadow:0 1px 4px #00000010}.avatar{background:#ecefdb;width:33px;height:33px;border-radius:50%;display:grid;place-items:center;font-size:11px;font-weight:600}.main{max-width:1500px;width:100%;margin:auto;padding:36px 45px 60px;animation:enter .28s ease}.page-head{display:flex;justify-content:space-between;align-items:flex-start;gap:20px;margin-bottom:27px}.page-head p{margin-top:7px;font-size:13px;color:var(--muted)}.badge{display:inline-flex;align-items:center;gap:7px;border:1px solid var(--line);border-radius:30px;padding:7px 11px;font-size:10px;white-space:nowrap;background:#fff}.dot{width:6px;height:6px;background:#688331;border-radius:50%}.hero{display:grid;grid-template-columns:1.2fr 1fr;background:var(--green);color:white;border-radius:18px;padding:34px 37px;min-height:284px;overflow:hidden;position:relative}.hero .eyebrow{color:var(--lime);font-weight:500;font-size:10px}.hero h1{margin:20px 0 12px;max-width:520px}.hero h1 span{color:var(--lime)}.hero p{font-size:12px;color:#d0dfd3;max-width:440px;line-height:1.9}.btn{display:inline-flex;justify-content:center;align-items:center;gap:9px;border:1px solid var(--line);border-radius:8px;background:white;padding:11px 17px;font-size:12px;font-weight:600;min-height:42px;text-decoration:none;transition:background .15s,transform .15s}.btn:hover{transform:translateY(-1px);background:#f0f3e3}.btn.primary{background:var(--green);color:white;border-color:var(--green)}.btn.primary:hover{background:#35625b}.btn.lime{background:var(--lime);color:var(--green);border-color:var(--lime)}.btn.ghost{background:transparent;border:1px solid #ffffff45;color:white}.btn.danger{color:#a64031;border-color:#edcfc9}.btn.small{padding:7px 11px;min-height:34px;font-size:11px}.hero .btn{margin-top:22px}.hero-art{position:relative;display:grid;place-items:center;min-height:226px}.orbit{width:223px;height:223px;border:1px solid #c4d0a642;border-radius:50%;position:relative;transform:rotate(-13deg)}.orbit:before{content:'';position:absolute;inset:29px;border:1px dashed #c4d0a650;border-radius:50%}.orbit:after{content:'';position:absolute;inset:62px;border:1px solid #c4d0a638;border-radius:50%}.orbit-core{position:absolute;inset:67px;display:grid;place-items:center;text-align:center;z-index:1;font:italic 28px Georgia;color:var(--lime);transform:rotate(13deg)}.orbit-label{position:absolute;font:12px 'Avenir Next',sans-serif;border-radius:6px;padding:11px 16px;z-index:2;box-shadow:0 6px 20px #10241a25;background:var(--lime);color:var(--green);transform:rotate(13deg)}.orbit-label:nth-child(2){top:0;left:64px}.orbit-label:nth-child(3){right:-27px;top:111px;background:#f0f4e1}.orbit-label:nth-child(4){bottom:-3px;left:68px;background:#cedbbb}.orbit-label:nth-child(5){left:-35px;top:75px;background:#e6c2a4}.art-caption{position:absolute;bottom:-7px;color:#bbcec2;letter-spacing:2px;font-size:8px}.stats{display:grid;grid-template-columns:repeat(3,1fr);margin:24px 0 32px;gap:15px}.stat{background:white;border:1px solid var(--line);border-radius:12px;padding:18px 22px;display:flex;align-items:center;gap:15px}.stat-icon{display:grid;place-items:center;width:40px;height:40px;background:var(--lime2);border-radius:10px;font-size:20px}.stat strong{font-size:24px;font-weight:600}.stat p{font-size:11px;color:var(--muted);margin-top:2px}.section-title{display:flex;justify-content:space-between;align-items:center;margin:25px 0 16px;gap:16px}.section-title h2{font-size:19px}.text-btn{border:0;background:transparent;color:var(--green);font-size:12px;padding:7px 0;font-weight:600}.grid-2{display:grid;grid-template-columns:minmax(0,1.35fr) minmax(0,1fr);gap:22px}.grid-equal{display:grid;grid-template-columns:1fr 1fr;gap:18px}.card{background:white;border:1px solid var(--line);border-radius:13px;padding:24px}.card h3{margin:10px 0}.card p{font-size:13px}.week-feature{position:relative;border-top:3px solid var(--green)}.week-feature h2{margin:12px 0;font-size:24px}.week-feature .date{font-size:11px;color:var(--muted)}.tags{display:flex;gap:7px;flex-wrap:wrap;margin:14px 0}.tag{font-size:10px;border-radius:5px;background:#eff2e5;padding:5px 8px}.subtle{padding:14px 17px;background:var(--lime2);border-radius:8px;font-size:12px;line-height:1.8}.deadlines{display:flex;flex-direction:column;gap:21px;margin-top:20px}.deadline{display:flex;align-items:center;gap:14px}.date-tile{border:1px solid var(--line);border-radius:8px;min-width:49px;text-align:center;overflow:hidden}.date-tile small{display:block;background:#f0f2e9;font-size:9px;letter-spacing:1px;padding:3px}.date-tile b{display:block;font-size:20px;padding:4px}.deadline p{font-size:12px;line-height:1.5}.deadline small{color:var(--muted);font-size:10px}.footer-note{font-size:10px;line-height:1.8;color:var(--muted);margin-top:30px;padding-top:18px;border-top:1px solid var(--line)}.tabs{display:flex;gap:25px;border-bottom:1px solid var(--line);margin-bottom:26px;overflow-x:auto}.tabs button{border:0;border-bottom:2px solid transparent;background:transparent;padding:14px 1px;font-size:13px;white-space:nowrap;color:var(--muted)}.tabs button.active{border-color:var(--green);color:var(--green);font-weight:600}.lesson-top{background:#e9eeda;border-radius:14px;padding:25px 29px;margin-bottom:18px;display:flex;align-items:center;justify-content:space-between;gap:20px}.lesson-top h1{font-size:30px;margin:12px 0 8px}.lesson-top p{font-size:12px}.week-display{font:italic 72px Georgia;color:#83906a;line-height:1}.goals{margin:18px 0 0;padding-left:21px;font-size:13px;line-height:2}.concepts{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:16px}.concept{padding:23px;border-radius:12px;border:1px solid var(--line);background:white}.concept-number{font-family:Georgia;font-style:italic;color:#90a16b;font-size:24px}.concept h3{margin:9px 0;font-size:18px}.concept p{font-size:13px;line-height:1.85}.example{background:#f3f5ee;border-left:2px solid #c4cf9b;padding:12px 14px;margin-top:15px;border-radius:0 6px 6px 0}.example strong{font-size:10px;display:block;margin-bottom:5px;color:#6e7d5c}.misconception{font-size:11px!important;color:#936347;margin-top:12px}.steps{list-style:none;padding:0;counter-reset:steps;margin:18px 0 0;display:grid;gap:14px}.steps li{counter-increment:steps;display:flex;gap:13px;font-size:13px;line-height:1.8}.steps li:before{content:counter(steps,decimal-leading-zero);font-size:11px;color:#7c8965;font-weight:bold;padding-top:2px;flex-shrink:0}.quiz{margin-bottom:18px}.quiz-title{display:flex;gap:12px;align-items:start;margin-bottom:18px}.quiz-title span{background:var(--lime2);border-radius:6px;min-width:29px;text-align:center;padding:6px;font-size:11px}.quiz-title h3{font-size:15px;margin:3px 0}.options{display:grid;gap:9px}.option{border:1px solid var(--line);border-radius:8px;padding:13px 15px;display:flex;gap:12px;align-items:flex-start;font-size:13px;cursor:pointer;line-height:1.6}.option:hover{background:#f6f8f0}.option.selected{border-color:var(--green);background:#eef3e7}.option.correct{border-color:#548144;background:#eff5e9}.option.incorrect{border-color:#b88069;background:#fbf0ec}.option input{margin-top:4px;accent-color:var(--green)}.feedback{margin-top:13px;padding:14px;border-radius:8px;font-size:12px;line-height:1.9;background:#f0f5e7}.feedback.wrong{background:#faf0e9}.flex{display:flex;align-items:center;gap:12px;flex-wrap:wrap}.spaced{justify-content:space-between}.stack{display:grid;gap:18px}.field{display:grid;gap:7px;font-size:12px}.field label{font-weight:600}.field input,.field textarea,.field select,.search-input{width:100%;border:1px solid #d5ddcc;border-radius:8px;padding:11px 13px;background:#fff;color:var(--ink);min-height:42px}.field textarea{min-height:120px;resize:vertical;line-height:1.8}textarea::placeholder,input::placeholder{color:#8d9588}.rubric{display:grid;gap:11px;margin:18px 0;font-size:13px}.rubric label{display:flex;gap:10px;align-items:flex-start;line-height:1.7}.rubric input{accent-color:var(--green);margin-top:5px}.alert{background:#f4eedc;border:1px solid #e9dec0;border-radius:9px;padding:14px 17px;font-size:12px;line-height:1.8}.empty{padding:40px 22px;text-align:center;color:var(--muted);font-size:13px;background:#f3f5ee;border-radius:10px}.chat-header{background:var(--green);border-radius:14px;padding:27px;color:white;margin-bottom:23px}.chat-header h1{font-size:29px;margin:13px 0}.chat-header p{color:#d8e3d1;font-size:12px}.chips{display:flex;gap:8px;flex-wrap:wrap;margin:15px 0}.chips button{border:1px solid var(--line);border-radius:24px;background:white;padding:9px 13px;font-size:11px;text-align:left}.chat-log{display:grid;gap:17px;margin:24px 0}.chat-question{padding:13px 18px;border-radius:13px 13px 2px 13px;background:#e8edda;justify-self:end;max-width:85%;font-size:13px;white-space:pre-wrap}.chat-answer{background:white;border:1px solid var(--line);border-radius:13px 13px 13px 2px;padding:22px;font-size:13px;line-height:1.9;max-width:95%}.chat-answer h3{font-size:15px;margin:7px 0}.chat-answer p{white-space:pre-wrap}.source{margin-top:12px;border-top:1px solid var(--line);padding-top:10px;color:var(--muted);font-size:10px}.ask-form{display:flex;gap:10px;align-items:end;position:sticky;bottom:15px;background:var(--paper);padding:14px 0}.ask-form .field{flex:1}.ask-form textarea{min-height:58px;max-height:160px}.assistant-tools{display:flex;justify-content:space-between;align-items:center;gap:12px}.room-code{font-size:43px;letter-spacing:7px;font-weight:600}.room-bar{background:var(--green);color:white;border-radius:13px;padding:24px 28px;display:flex;gap:18px;justify-content:space-between;align-items:center}.room-bar p{color:#ccd9ca;font-size:12px}.room-state{font-size:11px;border:1px solid #ffffff50;border-radius:20px;padding:7px 11px}.room-prompt{margin:24px 0;font-size:22px}.result{margin:14px 0}.result-label{display:flex;justify-content:space-between;gap:15px;font-size:12px;margin-bottom:7px;line-height:1.6}.bar{height:8px;border-radius:10px;background:#edf0e6;overflow:hidden}.bar i{display:block;height:100%;background:#76965a;transition:width .4s}.question-item,.response-item{border-bottom:1px solid var(--line);padding:16px 0}.question-item:last-child,.response-item:last-child{border:0}.question-item p,.response-item p{font-size:13px;white-space:pre-wrap;overflow-wrap:anywhere}.question-item small,.response-item small{color:var(--muted);font-size:10px}.reply{background:#f0f3e7;padding:12px;border-radius:7px;margin-top:11px;font-size:12px;white-space:pre-wrap}.question-actions{display:flex;gap:10px;margin-top:10px;align-items:center}.vote-up{background:#f0f3e7;border:1px solid var(--line);padding:5px 9px;border-radius:6px;font-size:11px}.vote-up.voted{background:var(--green);color:white}.timer{font-size:48px;font-family:Georgia;font-variant-numeric:tabular-nums;color:var(--green)}.note-item{padding:20px;background:white;border:1px solid var(--line);border-radius:11px;margin:16px 0}.note-item p{font-size:13px;white-space:pre-wrap}.mobile-menu{display:none;border:1px solid var(--line);border-radius:6px;background:white;padding:7px 10px}.mobile-close{display:none}.progress-track{height:5px;background:#e0e6d2;border-radius:6px;overflow:hidden;margin:9px 0}.progress-track i{display:block;background:#6a8953;height:100%;transition:width .3s}.schedule-grid{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:15px}.schedule-card{background:white;border:1px solid var(--line);border-radius:12px;padding:20px;text-align:left;display:flex;flex-direction:column;align-items:start}.schedule-card.current{border-color:#8b9b67;background:#f4f6e6}.schedule-card h3{font-size:15px;margin:12px 0 7px}.schedule-card p{font-size:11px;color:var(--muted)}.schedule-card .tag{margin-top:auto}.modal-backdrop{position:fixed;inset:0;background:#102d2799;z-index:100;display:grid;place-items:center;padding:20px}.modal{background:var(--paper);border-radius:15px;padding:28px;width:min(630px,100%);max-height:90vh;overflow-y:auto}.modal h2{margin-bottom:20px}.modal .field{margin:15px 0}details{border:1px solid var(--line);background:white;border-radius:9px;margin:11px 0;padding:15px 18px;font-size:13px}summary{cursor:pointer;font-weight:600;line-height:1.8}details p{margin-top:12px;color:var(--muted)}#toast{position:fixed;bottom:22px;left:50%;transform:translateX(-50%) translateY(100px);max-width:90vw;padding:13px 22px;background:var(--green);color:white;border-radius:9px;z-index:300;font-size:12px;transition:transform .25s;box-shadow:var(--shadow)}#toast.show{transform:translateX(-50%) translateY(0)}.storage-warn{background:#f5e6d6;padding:9px 15px;font-size:11px}.hide{display:none!important}.anchor{scroll-margin-top:20px}@keyframes enter{from{opacity:0;transform:translateY(5px)}to{opacity:1;transform:none}}@media(prefers-reduced-motion:reduce){*{animation:none!important;transition:none!important}}@media(min-width:1600px){.main{padding-top:45px}.hero{min-height:320px}.hero h1{font-size:45px}}@media(max-width:1150px){.shell{grid-template-columns:212px minmax(0,1fr)}.sidebar{padding:24px 13px}.main{padding:28px}.topbar{padding:0 28px}.hero{padding:29px}.hero h1{font-size:32px}.hero-art{transform:scale(.87)}.grid-2{grid-template-columns:1fr 1fr}.stats{gap:10px}.stat{padding:16px 13px;gap:9px}.stat strong{font-size:22px}.schedule-grid{grid-template-columns:repeat(2,minmax(0,1fr))}}@media(max-width:850px){.shell{grid-template-columns:1fr}.sidebar{position:fixed;left:-280px;width:260px;transition:left .2s;box-shadow:var(--shadow)}.sidebar.open{left:0}.mobile-close{display:block;border:0;background:none;position:absolute;right:11px;top:10px}.mobile-menu{display:block}.topbar{height:66px;padding:0 20px}.breadcrumbs{display:none}.main{padding:24px 20px 40px}.hero h1{font-size:33px}.grid-2{grid-template-columns:1fr 1fr}.lesson-top h1{font-size:26px}.page-head h1{font-size:30px}.hero-art{transform:scale(.85)}}@media(max-width:600px){.main{padding:23px 16px 40px}.hero{grid-template-columns:1fr;padding:28px 25px;min-height:260px}.hero-art{display:none}.hero h1{font-size:33px}.hero p{font-size:12px}.stats{grid-template-columns:repeat(3,minmax(0,1fr));gap:8px;margin-bottom:23px}.stat{display:block;padding:13px 11px}.stat-icon{display:none}.stat strong{font-size:21px}.stat p{font-size:9px}.grid-2,.grid-equal,.concepts{grid-template-columns:1fr}.card{padding:21px}.page-head{gap:9px;align-items:flex-start}.page-head .badge{display:none}.page-head h1{font-size:28px}.lesson-top{padding:23px;align-items:flex-start}.lesson-top h1{font-size:23px}.week-display{font-size:45px}.tabs{gap:22px}.schedule-grid{grid-template-columns:1fr}.room-bar{padding:20px;align-items:flex-start}.room-code{font-size:31px;letter-spacing:4px}.room-state{font-size:9px}.ask-form{gap:7px}.ask-form .btn{padding:12px}.chat-answer{max-width:100%;padding:18px}.chat-question{max-width:95%}.actions{gap:9px}.topbar{padding:0 16px}.small-hide{display:none}.option{padding:12px}.footer-note{font-size:9px}}@media print{.sidebar,.topbar,.tabs,.btn,.ask-form,.footer-note,.mobile-menu{display:none!important}.shell{display:block}.main{padding:0}.card,.concept{break-inside:avoid}.hero{color:black;background:white}body{background:white}}
/* Textbook-led visual learning, edition 2 */
.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}.textbook-viewer{background:white;border:1px solid var(--line);border-radius:15px;overflow:hidden;margin:25px 0}.textbook-heading{display:flex;justify-content:space-between;align-items:center;gap:16px;padding:23px 26px;border-bottom:1px solid var(--line)}.textbook-heading h3{margin:8px 0 0;font-size:20px}.textbook-stage{display:grid;grid-template-columns:minmax(0,1.12fr) minmax(0,1fr)}.textbook-picture{padding:26px;background:#fdfdf9;display:flex;flex-direction:column;justify-content:center;border-right:1px solid var(--line)}.image-zoom{border:0;background:transparent;position:relative;width:100%;padding:0}.image-zoom img{display:block;width:100%;height:330px;object-fit:contain;object-position:center}.image-zoom>span{position:absolute;bottom:8px;right:6px;border-radius:5px;background:#244b47e8;color:white;padding:6px 9px;font-size:10px}.image-credit{font-size:9px;line-height:1.65;color:#747d70;text-align:center;margin-top:15px;overflow-wrap:anywhere}.textbook-commentary{padding:27px;display:flex;flex-direction:column;justify-content:center;gap:13px;min-width:0}.textbook-commentary h3{font-size:22px;margin:0}.textbook-commentary p{font-size:13px;line-height:1.85}.textbook-commentary .source{font-size:9px;line-height:1.8;overflow-wrap:anywhere;margin-top:4px}.textbook-prompt{background:#f1f4df;border-radius:8px;padding:14px}.textbook-prompt>b{display:block;font-size:9px;letter-spacing:1.3px;color:#6d7a4a;margin-bottom:6px}.textbook-controls{border-top:1px solid var(--line);display:flex;align-items:center;justify-content:space-between;gap:12px;padding:16px 25px}.material-select{flex:1;min-width:0}.material-select select{width:100%;max-width:100%;border:1px solid var(--line);background:white;border-radius:7px;padding:9px 10px;color:var(--ink);font-size:11px;text-overflow:ellipsis}.learning-goals{margin:20px 0;background:#eef2e4}.concepts .concept-detail{margin:0;padding:18px 21px;background:white}.concept-detail>summary{display:flex;align-items:center;gap:14px;font-size:14px;list-style:none}.concept-detail>summary:after{content:'＋';margin-left:auto;font-size:15px;color:#7c8968}.concept-detail[open]>summary:after{content:'−'}.concept-detail>p{color:var(--ink);font-size:13px}.concept-detail .concept-number{font-size:25px}.concept-detail .example p{font-size:12px}.worked-detail{margin-top:18px}.image-modal{width:min(1120px,97vw);max-height:94vh;padding:22px}.textbook-enlarged{display:block;max-width:100%;max-height:73vh;width:auto;height:auto;margin:auto;object-fit:contain;background:white}.image-modal h2{font-size:20px}.practice-header{display:flex;gap:23px;justify-content:space-between;align-items:center;margin-bottom:23px}.practice-header h2{font-size:23px;margin:9px 0}.practice-header p{font-size:12px;max-width:680px;color:var(--muted);line-height:1.9}.practice-score{background:#e9efdb;border-radius:13px;text-align:center;padding:20px 24px;flex-shrink:0}.practice-score strong{display:block;font-size:33px;font-weight:600}.practice-score strong small{font-size:15px;color:var(--muted)}.practice-score>span{display:block;font-size:11px;margin-top:4px}.question-nav{display:flex;flex-wrap:wrap;gap:8px;margin:19px 0}.question-nav button{background:#fff;border:1px solid var(--line);border-radius:8px;min-width:35px;height:36px;padding:0 9px;font-size:12px}.question-nav button.active{border-color:var(--green);box-shadow:0 0 0 1px var(--green);background:var(--lime2);font-weight:700}.question-nav button.is-correct{background:#eaf1df;color:#42652e}.question-nav button.is-wrong{background:#f8eee6;color:#9c6037}.question-source{display:flex;align-items:center;gap:10px;font-size:10px;flex-wrap:wrap;color:var(--muted);margin-bottom:21px}.source-tag{background:#e9efda;color:var(--green);font-size:9px;letter-spacing:.8px;font-weight:600;border-radius:5px;padding:6px 8px}.question-copyright{font-size:9px;line-height:1.8;color:var(--muted);border-top:1px solid var(--line);margin-top:22px;padding-top:12px}.english-original{background:#f7f8f2;padding:12px 16px;margin:4px 0 20px}.english-original summary{font-size:11px;color:#667354}.english-original p,.english-original li{font-size:12px;line-height:1.85;color:var(--ink)}.english-original ol{margin:10px 0 5px;padding-left:23px}.quiz-title h3{font-size:17px;line-height:1.8}.footer-note p{font-size:10px;line-height:1.85}.footer-note p+p{margin-top:8px}.lesson-top{margin-bottom:15px}.lesson-top h1{font-size:27px}.lesson-top .week-display{font-size:60px}@media(max-width:1050px){.textbook-stage{grid-template-columns:1fr}.textbook-picture{border-right:0;border-bottom:1px solid var(--line)}.image-zoom img{height:300px}.textbook-commentary{gap:11px}.textbook-commentary .source{margin-top:0}.practice-header h2{font-size:21px}}@media(max-width:600px){.textbook-heading{padding:20px}.textbook-heading h3{font-size:17px}.textbook-heading .badge{padding:6px;font-size:9px}.textbook-picture{padding:18px}.image-zoom img{height:250px}.textbook-commentary{padding:21px}.textbook-commentary h3{font-size:19px}.textbook-controls{padding:13px 14px;gap:9px;flex-wrap:wrap}.textbook-controls .material-select{order:3;flex-basis:100%}.concept-detail>summary{font-size:13px}.practice-header{align-items:flex-start;gap:13px}.practice-header h2{font-size:21px}.practice-score{padding:12px;min-width:65px}.practice-score strong{font-size:25px}.practice-header p{font-size:11px}.quiz-title h3{font-size:15px}.question-source{gap:7px}.lesson-top h1{font-size:23px}.lesson-top .week-display{font-size:45px}.image-modal{padding:16px}.image-modal h2{font-size:17px}}@media print{.image-zoom>span,.textbook-controls,.question-nav{display:none}.textbook-stage{display:block}.textbook-picture{border:0}.textbook-viewer{break-inside:avoid}}
/* Let the narrow-screen grid shrink around horizontally scrollable tabs. */
.shell>div{min-width:0}.explanation-source{margin-top:12px;background:#ffffff70;font-size:11px}.explanation-source p{font-size:11px;overflow-wrap:anywhere}