:root{--navy:#113b50;--navy2:#1a5164;--ink:#193443;--muted:#617581;--teal:#176f70;--teal2:#d8efed;--gold:#bd7641;--light:#f4f7f6;--surface:#fff;--stroke:#dbe5e4;--rose:#fff0e8;--shadow:0 10px 40px rgba(15,47,56,.075);--radius:18px;--focus:#b26f36}
*,*::before,*::after{box-sizing:border-box}html{scroll-behavior:smooth}body{margin:0;background:#eff4f2;color:var(--ink);font-family:ui-sans-serif,system-ui,-apple-system,BlinkMacSystemFont,"Segoe UI",Arial,sans-serif;font-size:16px;line-height:1.56}button,textarea,input,select{font:inherit}button{cursor:pointer}button:disabled{cursor:not-allowed;opacity:.4}a{color:#0e6178}a:hover{text-decoration-thickness:2px}a:focus-visible,button:focus-visible,input:focus-visible,textarea:focus-visible{outline:3px solid var(--focus);outline-offset:3px}.skip-link{position:absolute;left:12px;top:-60px;padding:10px 14px;background:white;z-index:100}.skip-link:focus{top:12px}
.shell{min-height:100vh}.topbar{min-height:78px;display:flex;justify-content:space-between;align-items:center;gap:15px;padding:12px max(28px,calc((100% - 1420px)/2));background:#10384c;color:white}.brand{display:flex;align-items:center;gap:14px;padding:0;border:0;background:transparent;color:white;text-align:left}.brand-symbol{height:43px;width:43px;border:1px solid #7195a2;border-radius:13px;display:grid;place-items:center;font-size:30px;color:#86d1ce}.brand-text{display:grid;line-height:1.18;gap:4px}.brand-text strong{font-size:18px;letter-spacing:-.025em}.brand-text small{font-size:12px;letter-spacing:.025em;color:#c6d8db}.topbar-right{display:flex;align-items:center;gap:18px}.version{font-size:11px;border:1px solid #5e8995;color:#cde1e4;padding:6px 10px;border-radius:40px;font-weight:750;letter-spacing:.06em}.utility-button{background:#24566b;color:white;border:1px solid #538095;border-radius:10px;padding:10px 14px;font-weight:650}.utility-button:hover{background:#356b80}
.app-layout{display:grid;grid-template-columns:275px minmax(0,1fr);max-width:1450px;margin:0 auto;min-height:calc(100vh - 128px);background:#f6f9f8}.sidebar{padding:30px 20px 28px;background:#f0f5f4;border-right:1px solid var(--stroke);display:flex;flex-direction:column}.sidebar-heading{font-weight:800;display:flex;justify-content:space-between;gap:6px;color:#3f5b69;font-size:11px;letter-spacing:.105em}.sidebar-heading span{letter-spacing:0;font-size:13px}.progress-track{margin:15px 0 24px;background:#dce6e4;height:7px;border-radius:12px;overflow:hidden}.progress-fill{height:100%;background:#27847d;border-radius:12px;transition:width .3s}.lesson-nav{display:grid;gap:5px}.lesson-link{border:1px solid transparent;background:transparent;width:100%;border-radius:12px;text-align:left;display:flex;align-items:center;gap:12px;padding:11px 9px;color:#416071;line-height:1.22;min-height:57px}.lesson-link:hover:not(:disabled),.lesson-link.active{background:#fff;border-color:var(--stroke)}.lesson-link.active{box-shadow:0 2px 14px #cfdcda70;color:#17394b}.lesson-link.locked{color:#859a9e}.lesson-num{display:grid;place-items:center;min-width:32px;height:32px;background:#dce8e7;border-radius:10px;font-size:12px;font-weight:800;color:#3c6870}.lesson-link.done .lesson-num{background:#d1eee3;color:#176951}.lesson-link.active .lesson-num{background:#cee6e8;color:#11586b}.lesson-label{font-size:12px;font-weight:750;flex:1}.lesson-status{font-size:14px;color:#61828a}.sidebar-bottom{margin-top:auto;padding-top:32px}.small-link{font-size:12px;color:#526a74;background:transparent;border:0;padding:8px 2px;text-align:left;text-decoration:underline;text-underline-offset:3px}.small-link:hover{color:#0d5f6c}
#main{padding:38px clamp(20px,4vw,68px) 70px;max-width:1180px;width:100%;margin:0 auto;outline:none}.global-footer{background:#e6eeeb;border-top:1px solid #d5e4df;display:flex;align-items:center;justify-content:space-between;gap:20px;padding:12px max(24px,calc((100% - 1370px)/2));color:#57717a;font-size:11px}.eyebrow{font-size:11px;font-weight:800;letter-spacing:.13em;text-transform:uppercase;color:#4a797d;margin:0 0 13px}.hero{margin-top:0;display:grid;grid-template-columns:1.1fr .9fr;gap:28px;align-items:center;background:linear-gradient(124deg,#113d50,#1c6471);padding:clamp(24px,4vw,47px);border-radius:24px;color:white;overflow:hidden;min-height:300px;box-shadow:var(--shadow)}.hero .eyebrow{color:#a6d5d1}.hero h1{color:white;font-size:clamp(31px,4vw,52px);line-height:1.12;letter-spacing:-.04em;max-width:580px;margin:0 0 22px;font-weight:800}.hero p{color:#e2efec;max-width:540px;font-size:15px;margin:0 0 20px}.hero-media{border-radius:16px;background:#fff;overflow:hidden;box-shadow:0 17px 44px #06263860}.hero-media img{width:100%;display:block;aspect-ratio:4/3;object-fit:cover}.hero .button-primary{background:#fff;color:#153f52}.hero .button-primary:hover{background:#e5faf4}.subtle{font-size:13px;color:var(--muted)}.intro-section{margin-top:34px}.section-h2{font-size:23px;letter-spacing:-.03em;line-height:1.3;margin:0 0 16px}.intro-grid{display:grid;grid-template-columns:repeat(2,1fr);gap:14px}.info-card{background:#fff;border:1px solid var(--stroke);border-radius:16px;padding:22px;display:flex;gap:13px;align-items:flex-start}.card-icon{display:grid;place-items:center;flex-shrink:0;width:36px;height:36px;border-radius:10px;background:#e6f2f0;font-size:18px;color:#21737b}.info-card strong{display:block;font-size:15px;margin-bottom:5px}.info-card p{margin:0;color:#58707c;font-size:14px}.lesson-grid{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:12px;margin-top:22px}.lesson-card{border:1px solid var(--stroke);background:white;text-align:left;border-radius:16px;padding:19px;display:flex;gap:15px;align-items:flex-start;min-height:124px;color:var(--ink)}.lesson-card:not(:disabled):hover{border-color:#87b4aa;box-shadow:var(--shadow);transform:translateY(-1px)}.lesson-card.selected{border-color:#75aaa3}.chapter-number{font-weight:800;color:#2c7777;display:grid;place-items:center;min-width:37px;height:37px;border-radius:11px;background:#ebf5f2}.lesson-card h3{margin:0 0 6px;font-size:16px;letter-spacing:-.01em}.lesson-card p{font-size:13px;color:#70828a;margin:0}.chapter-state{display:inline-block;margin-top:13px;font-size:11px;color:#61767d;font-weight:760;text-transform:uppercase;letter-spacing:.04em}.chapter-state.complete{color:#19745d}.chapter-state.current{color:#127388}.button{display:inline-flex;justify-content:center;align-items:center;gap:10px;border:1px solid transparent;border-radius:12px;padding:13px 19px;font-weight:750;min-height:48px;text-align:center;text-decoration:none;font-size:14px;transition:background .18s,border-color .18s,transform .18s}.button-primary{background:#156c70;color:#fff}.button-primary:hover:not(:disabled){background:#10595e}.button-secondary{background:#f0f7f6;color:#195868;border-color:#cfdfdf}.button-secondary:hover:not(:disabled){background:#e1efed}.button-ghost{background:transparent;color:#326270;border-color:#d0dedc}.button-ghost:hover:not(:disabled){background:#e9f3f1}.button-danger{background:#a34140;color:white}.button-danger:hover{background:#893332}.button.block{width:100%}.button-row{display:flex;flex-wrap:wrap;align-items:center;gap:12px}.button-row.push{justify-content:space-between}.button[aria-busy="true"]{opacity:.6}
.lesson-head{display:flex;justify-content:space-between;align-items:flex-start;gap:18px;margin-bottom:27px}.lesson-head h1{font-size:clamp(26px,3vw,39px);line-height:1.15;letter-spacing:-.04em;margin:5px 0 12px}.lesson-head p{margin:0;color:#657b83;font-size:14px}.step-badge{white-space:nowrap;border-radius:40px;background:#e4efef;color:#2a686e;padding:8px 13px;font-size:12px;font-weight:800}.step-dots{display:flex;align-items:center;gap:6px;margin-bottom:22px}.step-dot{height:6px;flex:1;background:#dbe8e6;border-radius:10px}.step-dot.done{background:#72b6aa}.step-dot.current{background:#247e7a}.lesson-panel{border:1px solid var(--stroke);background:white;border-radius:22px;padding:clamp(18px,3.6vw,39px);box-shadow:var(--shadow)}.panel-kicker{font-size:11px;text-transform:uppercase;letter-spacing:.12em;font-weight:800;color:#327b77;margin:0 0 9px}.lesson-panel h2{font-size:clamp(23px,2.9vw,31px);line-height:1.22;letter-spacing:-.027em;margin:0 0 18px;color:#173849}.lesson-panel p{font-size:15px;max-width:78ch;margin:0 0 14px}.lesson-panel p:last-child{margin-bottom:0}.explain{padding:2px 0}.explain strong{color:#104f5d}.media-frame{margin:22px 0 22px;background:#f0f5f4;border:1px solid #dae5e3;border-radius:15px;overflow:hidden}.media-frame img{display:block;width:100%;height:auto}.media-frame img:focus{outline:2px solid orange}.media-caption{padding:9px 15px;font-size:12px;color:#667b86;background:#f5f8f8;border-top:1px solid #dde5e3}.mini-pair{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:14px;margin-top:22px}.mini-pair .media-frame{margin:0}.mini-pair .media-caption{text-align:center;font-weight:750}.term-strip{border-left:4px solid #3b9790;background:#eaf5f2;border-radius:0 10px 10px 0;padding:13px 17px;margin:19px 0;font-size:14px;color:#275462}.bridge{background:#f2f7f6;border-radius:12px;padding:15px 18px;color:#456470;margin:23px 0 0;font-size:14px}.question{background:#f6faf8;border-radius:14px;padding:22px;margin:18px 0 20px;border:1px solid #dceae5}.question-title{font-weight:800;margin:0 0 13px;font-size:16px}.question p{margin-bottom:10px}.options{display:grid;gap:11px;margin:18px 0}.option{width:100%;text-align:left;padding:14px 17px;border:1.5px solid #d1e0df;border-radius:12px;background:#fff;color:#254553;display:flex;align-items:flex-start;gap:11px;min-height:55px}.option:hover:not(:disabled){background:#f0f8f6;border-color:#74a9a4}.option.selected{border-color:#268477;background:#e8f5f0}.option .letter{display:grid;place-items:center;flex:0 0 28px;height:28px;border-radius:8px;background:#e8efef;color:#3e6971;font-size:12px;font-weight:800}.option span:last-child{flex:1}.feedback{border-radius:12px;padding:14px 16px;margin:15px 0 0;border:1px solid #d5e3e1;background:#ecf5f3;color:#315d61;font-size:14px}.feedback.good{background:#e8f6ee;border-color:#b8dec8;color:#1b6446}.feedback.bad{background:#fff3eb;border-color:#edd2bb;color:#824f29}.feedback strong{display:block;margin-bottom:2px}.quiz-footer{display:flex;gap:10px;justify-content:flex-end;margin-top:14px}.explanation-note{margin-top:21px;color:#54717e;font-size:13px}.base-grid{display:grid;gap:5px;grid-template-columns:repeat(5,minmax(0,1fr));max-width:550px}.base{display:grid;place-items:center;background:#edf2f2;color:#143f52;font-weight:800;min-height:51px;border-radius:9px;border:1px solid #cbdcdb;letter-spacing:.02em}.base.old{background:#dcebf5;border-color:#b5d4ed}.base.new{background:#fff0e1;border-color:#efd4b7}.base-picker{min-height:52px;background:#fff;border:2px solid #e3b584}.base-picker.selected{border-color:#156f7d;background:#e6f2f0}.base-picker.correct{border-color:#288667;background:#eaf5ee}.base-picker.incorrect{border-color:#b77149}.base-card-title{color:#607781;font-size:12px;font-weight:750;margin:15px 0 8px}.choice-inline{display:flex;flex-wrap:wrap;gap:9px;margin:11px 0}.choice-inline button{min-width:51px;border:1px solid #cadedd;background:white;border-radius:10px;padding:10px;font-weight:800;color:#225268}.choice-inline button.selected{background:#d6eee8;border-color:#22776f}.choice-inline button:hover{border-color:#197770}.input-label{display:block;font-weight:750;font-size:14px;margin:15px 0 6px}.select{width:100%;background:#fff;border:1px solid #aac6c5;border-radius:10px;padding:12px;color:var(--ink);min-height:48px}.select:focus-visible{outline:3px solid var(--focus)}.answer-area{display:block;width:100%;border:1.5px solid #cbdcdb;border-radius:12px;min-height:127px;padding:14px 16px;line-height:1.55;resize:vertical;background:#fff;color:#1c3e50}.model-answer{padding:20px;border-left:4px solid #1a8580;background:#e9f6f2;border-radius:0 13px 13px 0;margin:19px 0}.model-answer h3{font-size:16px;margin:0 0 8px}.model-answer p{font-size:14px;margin:0 0 10px}.criteria{display:grid;gap:8px;margin:14px 0}.criteria li{font-size:14px}.checkpoint{background:#f0f7f6;border:1px solid #c8dfd9;padding:21px;border-radius:14px;margin:20px 0}.checkpoint h3{font-size:16px;margin:0 0 9px}.checkpoint p{font-size:14px;margin:0 0 11px}.checkpoint .mark{display:inline-block;font-size:11px;color:#216e74;background:#dcf0ee;border-radius:20px;padding:4px 9px;font-weight:800;margin:0 0 9px}.checkpoint .button{margin-top:8px}.next-controls{display:flex;gap:11px;align-items:center;justify-content:space-between;margin-top:22px}.next-controls .button-primary{margin-left:auto}.small-status{font-size:13px;color:#6c7f84}.complete-banner{background:linear-gradient(125deg,#144758,#1c7775);border-radius:20px;padding:32px;color:white;margin:0 0 23px}.complete-banner h1{font-size:clamp(27px,3vw,43px);line-height:1.12;margin:0 0 15px}.complete-banner p{color:#e0f3f0;max-width:70ch}.resource-grid{display:grid;grid-template-columns:repeat(2,1fr);gap:15px;margin:24px 0}.resource{border:1px solid var(--stroke);border-radius:15px;background:#fff;padding:24px}.resource h2{margin:0 0 9px;font-size:19px}.resource p{color:#627a80;font-size:14px}.resource .button{margin-top:8px}.resource a.button{text-decoration:none}.confirm-dialog{width:min(94vw,460px);border:1px solid var(--stroke);border-radius:19px;box-shadow:0 25px 80px #15364463;padding:0}.confirm-dialog::backdrop{background:rgba(9,37,51,.52)}.dialog-inner{padding:27px}.dialog-inner h2{margin:0 0 10px}.dialog-inner p{color:#637d85}.dialog-actions{display:flex;justify-content:flex-end;gap:10px}.replay{border:1px solid #b3d4d1;background:#fff;border-radius:8px;padding:8px 11px;color:#1a606e;font-size:12px;font-weight:750}.replay:hover{background:#edf6f2}.sr-only{position:absolute!important;width:1px;height:1px;padding:0;margin:-1px;overflow:hidden;clip:rect(0,0,0,0);white-space:nowrap;border:0}.offline-pill{margin-top:13px;color:#f2e4a6;font-size:12px}
@media(max-width:1020px){.app-layout{grid-template-columns:225px minmax(0,1fr)}.sidebar{padding:20px 12px}.lesson-label{font-size:11px}#main{padding:27px 25px 60px}.hero{gap:18px;padding:26px}.lesson-panel{padding:26px}}@media(max-width:740px){.topbar{padding:12px 17px;min-height:67px}.brand-text strong{font-size:15px}.brand-text small{font-size:11px}.brand-symbol{width:36px;height:36px}.version{display:none}.utility-button{padding:9px 12px;font-size:12px}.app-layout{display:block}.sidebar{border-right:0;border-bottom:1px solid var(--stroke);padding:12px 15px;display:block}.sidebar-heading,.sidebar .progress-track,.sidebar-bottom{display:none}.lesson-nav{display:flex;gap:7px;overflow-x:auto;scrollbar-width:thin;padding-bottom:4px}.lesson-link{min-width:54px;width:auto;flex:none;min-height:46px;padding:5px 7px;justify-content:center}.lesson-link .lesson-label,.lesson-link .lesson-status{display:none}.lesson-num{height:34px;min-width:35px}.sidebar .lesson-link.active{border-color:#8eb6b1}#main{padding:22px 15px 51px}.hero{grid-template-columns:1fr;padding:25px}.hero-media{display:none}.hero h1{font-size:34px}.lesson-grid,.intro-grid,.resource-grid{grid-template-columns:1fr}.lesson-head{gap:10px}.lesson-head h1{font-size:26px}.step-badge{font-size:10px;padding:6px 8px}.lesson-panel{border-radius:16px;padding:19px}.lesson-panel h2{font-size:23px}.lesson-panel p{font-size:14px}.mini-pair{grid-template-columns:1fr}.next-controls{flex-wrap:wrap}.next-controls .button{flex:1}.global-footer{display:block;padding:11px 16px}.global-footer span{display:block}.global-footer span+span{margin-top:3px}}@media(max-width:380px){.brand-symbol{display:none}.topbar-right{gap:6px}.hero h1{font-size:29px}.next-controls .button{padding:11px 9px;font-size:12px}.lesson-head h1{font-size:23px}}@media(prefers-reduced-motion:reduce){html{scroll-behavior:auto}*{animation:none!important;transition:none!important}}@media print{.topbar,.sidebar,.global-footer,.next-controls{display:none!important}#main{padding:0}.lesson-panel{border:0;box-shadow:none}}