@import url('https://fonts.googleapis.com/css2?family=Be+Vietnam+Pro:wght@400;450;500;550;600;650;700;750;800&display=swap');
:root{--ink:#202638;--muted:#85899b;--purple:#7461dc;--pale:#eeebfc;--border:#e9eaf0;--bg:#f7f8fc}*{box-sizing:border-box}body{margin:0;color:var(--ink);background:var(--bg);font:14px 'Be Vietnam Pro',system-ui,sans-serif}button,input,select{font:inherit}button,a,input,select{ -webkit-tap-highlight-color:transparent}button{cursor:pointer}a{color:inherit;text-decoration:none}button{border:0;background:none;color:inherit}button:focus-visible,a:focus-visible,input:focus-visible,select:focus-visible,summary:focus-visible{outline:3px solid #ae9df4;outline-offset:4px}button:disabled{opacity:.3;cursor:default}.sidebar{width:248px;position:fixed;inset:0 auto 0 0;background:#fff;border-right:1px solid var(--border);padding:35px 22px 20px;display:flex;flex-direction:column;z-index:20}.brand{display:flex;gap:12px;align-items:center;font-size:23px;font-weight:800;letter-spacing:-1px}.brandmark{background:var(--purple);color:white;display:grid;place-items:center;width:35px;height:38px;border-radius:12px;font-size:23px;letter-spacing:-5px;padding-right:5px}.brandlight{font-weight:450;font-size:19px}.sidebar-label{font-size:9px;font-weight:600;color:#a7a9b7;letter-spacing:1.3px;margin:46px 10px 15px}.nav-active{display:flex;align-items:center;gap:12px;background:var(--pale);color:#7560d1;padding:15px 12px;border-radius:10px;text-align:left;font-size:12px;font-weight:600}.count{margin-left:auto;background:#ded8f8;padding:3px 6px;border-radius:5px;font-size:10px}.test-head{font-size:9px;font-weight:600;color:#969aab;letter-spacing:1px;margin:33px 10px 16px;display:flex;justify-content:space-between}.test-head span{font-size:8px;background:#f5f5f9;padding:3px 5px;border-radius:3px;letter-spacing:0}#tests{overflow:auto;min-height:0}.test-button{display:flex;align-items:center;gap:12px;width:100%;padding:12px;margin-bottom:3px;border-radius:9px;text-align:left;font-size:12px;color:#7e8294}.test-button.active{background:#f7f6fd;color:var(--purple);font-weight:650}.test-number{width:25px;height:25px;display:grid;place-items:center;border:1px solid var(--border);background:white;border-radius:7px;font-size:10px}.test-button.active .test-number{border-color:#d5cdf6;background:#efebfc}.test-button .chevron{margin-left:auto;font-size:16px}.sidebar-bottom{border-top:1px solid var(--border);padding:22px 4px 0;margin-top:auto;display:flex;gap:10px;align-items:center;font-size:10px;color:#6e7386}.sidebar-bottom small{display:block;font-size:9px;color:#a0a3b2;margin-top:6px}.small-icon{border-radius:50%;background:#eaf5ef;color:#6caa8c;width:28px;height:28px;display:grid;place-items:center}.workspace{margin-left:248px}header{height:78px;border-bottom:1px solid var(--border);display:flex;align-items:center;justify-content:space-between;padding:0 45px;background:#ffffff88;font-size:11px}.breadcrumb{color:#9c9fae;display:flex;gap:16px;align-items:center}.breadcrumb b{font-weight:500;color:#555c71}.header-right{display:flex;align-items:center;gap:9px;color:#989cad;font-size:10px}.status-dot{height:6px;width:6px;background:#87b99a;border-radius:50%}.avatar{display:grid;place-items:center;width:31px;height:31px;margin-left:20px;background:#eae5fa;border:3px solid white;border-radius:50%;color:#9382c8;font-weight:600}main{max-width:1320px;padding:40px 45px 28px;margin:auto}.eyebrow{color:#9686c3;font-size:9px;letter-spacing:2px;font-weight:600;margin-bottom:13px}.title-row{display:flex;justify-content:space-between;gap:30px;align-items:center}h1{font-size:30px;font-weight:650;line-height:1.4;letter-spacing:-1px;margin:0}h1 br{display:none}.intro{font-size:11px;color:#9295a5;margin-top:12px;line-height:1.8}.overall{min-width:126px;padding-left:25px;border-left:1px solid var(--border)}.overall strong{font-size:25px;font-weight:600}.overall strong span{font-size:13px;font-weight:400;color:#a1a4b4}.overall small{font-size:9px;display:block;color:#9c9fae;margin-top:5px}.progress-track{height:4px;background:#eae7f4;margin-top:12px;border-radius:9px}.progress-track i{display:block;background:#a595e5;height:100%;width:0;border-radius:9px}.part-tabs{display:flex;gap:9px;margin:29px 0 25px;border-bottom:1px solid var(--border);padding-bottom:17px}.part-tab{padding:10px 15px;border-radius:8px;font-size:11px;color:#9194a5;display:flex;align-items:center;gap:10px}.part-tab.active{background:var(--purple);color:white;box-shadow:0 4px 10px #7461dc20}.part-tab span{font-size:9px;opacity:.8}.study-grid{display:grid;grid-template-columns:270px minmax(0,1fr);gap:25px;align-items:start}.lesson-list{background:white;border:1px solid var(--border);border-radius:14px;overflow:hidden}.section-head{display:flex;align-items:center;justify-content:space-between;padding:24px 21px 18px}h2{margin:0;font-weight:600}.section-head h2{font-size:13px}.section-head p{font-size:10px;color:#a0a3b2;margin:8px 0 0}.list-icon{color:#b4b7c6;font-size:24px}.search-wrap{display:flex;align-items:center;margin:0 16px 16px;border:1px solid #edecf3;border-radius:7px;padding:0 10px;gap:8px;background:#fcfcfe;color:#a4a7b7}.search-wrap input{border:0;background:none;width:100%;padding:10px 0;font-size:10px;outline:none;color:#62677b}.search-wrap input::placeholder{color:#b1b3bf}.lessons{padding:0 10px;max-height:510px;overflow:auto;scrollbar-width:thin;scrollbar-color:#e2ddf5 transparent}.lesson-button{padding:14px 11px;display:flex;gap:11px;align-items:center;width:100%;border:1px solid transparent;border-radius:9px;text-align:left;margin-bottom:4px}.lesson-button.active{background:#f2effd;border-color:#e5dff9}.lesson-button:hover:not(.active){background:#faf9fd}.lesson-num{height:32px;min-width:32px;border:1px solid var(--border);border-radius:9px;display:grid;place-items:center;font-size:11px;color:#9699ab;background:white}.active .lesson-num{background:#7461dc;color:white;border-color:#7461dc}.lesson-detail{min-width:0}.lesson-detail strong{font-size:11px;font-weight:550;display:block}.lesson-detail small{font-size:9px;color:#a2a4b4;display:block;margin-top:6px;white-space:nowrap;overflow:hidden;text-overflow:ellipsis;max-width:145px}.active .lesson-detail strong{color:#7963d2}.lesson-check{margin-left:auto;color:#8fae9c;font-size:12px}.list-footer{font-size:8px;color:#b0b3bf;text-align:center;border-top:1px solid #f2f1f7;margin-top:16px;padding:17px 0}.player-card{border:1px solid #e4e0f3;border-radius:15px;padding:22px 28px 17px;background:linear-gradient(115deg,#faf9ff,#f2effc);position:relative}.player-top{display:flex;justify-content:space-between;align-items:center}.pill{font-size:8px;letter-spacing:1px;font-weight:600;color:#8b75ca;background:#eae3fb;padding:6px 9px;border-radius:5px}.icon-button{font-size:19px;width:31px;height:31px;color:#9b90ba;display:grid;place-items:center;border-radius:7px}.icon-button[aria-pressed=true]{color:#b8952e;background:#fff3d2}.player-heading{display:flex;justify-content:space-between;align-items:center;margin:15px 0 16px}.player-heading h2{font-size:26px;letter-spacing:-.7px}.player-heading p{font-size:10px;color:#a49ab8;margin:9px 0}.audio-art{display:flex;gap:5px;align-items:center;height:50px;margin-right:12px}.audio-art i{background:#c6b8ed;width:5px;border-radius:8px;height:20px}.audio-art i:nth-child(3n){height:39px}.audio-art i:nth-child(2n){height:29px}.waveform{height:39px;display:flex;gap:3px;align-items:center;overflow:hidden;margin:13px 0 7px}.waveform i{flex:1;min-width:2px;background:#dcd4f2;border-radius:3px}.waveform i.played{background:#9c87d9}input[type=range]{width:100%;margin:0;accent-color:#8e76d0;height:4px;cursor:pointer}.time-row{display:flex;justify-content:space-between;font-size:9px;color:#a298b5;margin-top:8px;font-variant-numeric:tabular-nums}.controls{display:flex;justify-content:space-between;align-items:center;margin-top:12px}.speed-control select{border:1px solid #e3dced;border-radius:7px;padding:5px 6px;background:#ffffff55;color:#9282aa;font-size:10px}.primary-controls{display:flex;align-items:center;gap:16px}.primary-controls .icon-button{font-size:16px}.primary-controls #replay{font-size:26px}.play-button{background:var(--purple);color:white;width:49px;height:49px;border-radius:50%;box-shadow:0 5px 12px #7461dc30;font-size:18px;display:grid;place-items:center;padding-left:4px}.loop-button{font-size:20px;color:#a092b7;display:flex;align-items:center;gap:5px;border-radius:7px;padding:5px}.loop-button span{font-size:10px}.loop-button[aria-pressed=true]{background:#e2d9fa;color:#7559bf}.audio-status{font-size:10px;color:#ad6e68;min-height:2px;margin-top:7px}.learning-tools{display:flex;gap:20px;align-items:center;padding:23px 1px}.switch-label{display:flex;align-items:center;gap:7px;font-size:10px;color:#8b8f9f;cursor:pointer}.switch-label input{position:absolute;opacity:0;width:30px;height:20px}.switch{height:16px;width:29px;border-radius:10px;background:#dddfe8;position:relative;transition:.2s}.switch:before{content:'';height:12px;width:12px;position:absolute;top:2px;left:2px;border-radius:50%;background:white;box-shadow:0 1px 3px #0001;transition:.2s}.switch-label input:checked+.switch{background:#9180d8}.switch-label input:checked+.switch:before{transform:translateX(13px)}.switch-label input:focus-visible+.switch{outline:3px solid #b5a2eb;outline-offset:3px}.content-card{border:1px solid var(--border);background:white;border-radius:13px;padding:25px;min-height:190px}.hidden-state{display:flex;flex-direction:column;align-items:center;justify-content:center;text-align:center;padding:16px 10px;color:#a4a7b5}.hidden-state .hidden-icon{font-size:27px;width:55px;height:55px;display:grid;place-items:center;background:#f7f5fc;color:#b5a8d4;border-radius:50%;margin-bottom:14px}.hidden-state h3{font-size:12px;font-weight:500;color:#8a8da0;margin:0 0 8px}.hidden-state p{font-size:10px;line-height:1.8;max-width:310px;margin:0}.text-section+.text-section{border-top:1px solid var(--border);padding-top:20px;margin-top:20px}.text-label{font-size:9px;color:#9a8aba;letter-spacing:1.3px;font-weight:600;margin:0 0 15px}.transcript{font-size:13px;line-height:1.95;color:#555c71;white-space:pre-line}.translation{font-size:12px;color:#7d8394}.question{padding:16px 0;border-bottom:1px solid #f0eff5}.question:first-child{padding-top:0}.question:last-child{border-bottom:0;padding-bottom:0}.question-title{font-size:12px;line-height:1.8;margin:0 0 12px;font-weight:500}.answer-options{display:grid;grid-template-columns:1fr 1fr;gap:7px}.answer-option{text-align:left;border:1px solid var(--border);border-radius:7px;display:flex;align-items:flex-start;gap:8px;padding:10px;font-size:11px;line-height:1.5;background:#fdfdfe}.answer-option .letter{font-size:10px;color:#a0a1b1;background:#f1f1f7;border-radius:4px;padding:2px 5px}.answer-option.selected{border-color:#b8a9e9;background:#f4f0ff}.answer-option.correct{border-color:#a8d3b8;background:#eff8f2;color:#4f8d65}.answer-option.wrong{border-color:#e3b5b5;background:#fff2f2;color:#ab6868}.key-result{font-size:11px;color:#6a9179;margin-top:10px}.lesson-actions{display:flex;justify-content:space-between;align-items:center;margin-top:18px;gap:10px}.done-button{background:white;border:1px solid var(--border);border-radius:7px;font-size:10px;padding:10px 12px;color:#8e8b9f}.done-button[aria-pressed=true]{background:#eef7f1;color:#629178;border-color:#cbe1d2}.lesson-actions a{font-size:9px;color:#a19aaf}.tips{margin-top:25px;color:#9599a9;font-size:10px;line-height:1.8}.tips summary{cursor:pointer}.tips p{font-size:11px}.graphic-card{background:white;border:1px solid var(--border);border-radius:12px;padding:18px;margin-bottom:15px}.graphic-card img{display:block;max-width:100%;max-height:300px;object-fit:contain;margin:auto}.graphic-card p{font-size:10px;color:#9397a6}.source-note{font-size:10px;line-height:1.8;color:#9a91ab;background:#f3f0fa;border-radius:8px;padding:12px;margin:0 0 14px}footer{max-width:1320px;margin:auto;padding:20px 45px 26px;color:#b8bac7;font-size:10px;display:flex;justify-content:space-between}footer span{font-size:9px}.sr-only{position:absolute;width:1px;height:1px;padding:0;overflow:hidden;clip:rect(0,0,0,0);white-space:nowrap;border:0}.mobile-select{display:none}.empty-results{font-size:11px;color:#9b9eae;padding:20px;line-height:1.7}
@media(min-width:1450px){.study-grid{grid-template-columns:305px 1fr}.lesson-detail small{max-width:170px}main{padding-top:50px}.player-card{padding:26px 32px}.waveform{height:48px}.content-card{min-height:230px}}
@media(max-width:1150px){.sidebar{width:210px;padding-left:16px;padding-right:16px}.workspace{margin-left:210px}main{padding:30px 25px}header{padding:0 25px}.study-grid{grid-template-columns:220px minmax(0,1fr);gap:18px}.part-tab{padding:10px}.part-tab span{display:none}h1{font-size:25px}.learning-tools{gap:12px}.switch-label{font-size:9px}.player-card{padding:20px}.primary-controls{gap:8px}.lesson-detail small{max-width:115px}.answer-options{grid-template-columns:1fr}}
@media(max-width:850px){.sidebar{width:178px;padding:25px 12px}.workspace{margin-left:178px}.brand{font-size:19px;gap:8px}.brandlight{font-size:16px}.brandmark{width:30px;height:33px}.sidebar-label{font-size:7px}.nav-active{font-size:10px;padding:12px 8px;gap:7px}.test-head{font-size:8px}.test-head span{display:none}.study-grid{grid-template-columns:1fr}.lesson-list{order:2}.study-panel{order:1}.lessons{max-height:280px;display:grid;grid-template-columns:1fr 1fr}.title-row{align-items:start}.overall{min-width:90px;padding-left:16px}h1{font-size:24px}h1 br{display:block}.intro{max-width:320px}.learning-tools{justify-content:space-between}.switch-label{font-size:10px}.answer-options{grid-template-columns:1fr 1fr}footer{padding:20px 25px}}
@media(max-width:580px){.sidebar{display:none}.workspace{margin-left:0}header{height:58px;padding:0 20px}.header-right{font-size:9px}.avatar{margin-left:8px}main{padding:27px 18px 20px}.eyebrow{font-size:8px;letter-spacing:1.5px}h1{font-size:26px}.intro{font-size:10px;max-width:270px}.overall{min-width:73px;padding-left:12px}.overall strong{font-size:22px}.overall strong span{font-size:11px}.overall small{font-size:8px}.title-row{gap:14px}.mobile-select{display:flex;align-items:center;gap:12px;margin-top:17px;font-size:11px;color:#9694a8}.mobile-select select{background:white;border:1px solid var(--border);border-radius:7px;padding:9px 12px;flex:1;color:#716585}.part-tabs{margin:17px 0 19px;justify-content:space-between;gap:5px;padding-bottom:14px}.part-tab{flex:1;justify-content:center;font-size:10px;padding:10px 7px}.player-card{padding:18px 20px}.player-heading h2{font-size:25px}.learning-tools{gap:8px;padding:21px 0}.switch-label{gap:5px;font-size:9px}.switch{width:25px;height:15px}.switch:before{width:11px;height:11px}.switch-label input:checked+.switch:before{transform:translateX(10px)}.content-card{padding:20px}.answer-options{grid-template-columns:1fr}.primary-controls{gap:12px}.play-button{height:47px;width:47px}.lesson-list .section-head{padding:20px}.lesson-detail small{max-width:115px}.lesson-button{padding:12px 7px;gap:8px}.lesson-num{min-width:28px;width:28px;height:28px}footer{padding:16px 18px 28px;font-size:9px}footer span{font-size:8px}}
@media(prefers-reduced-motion:reduce){*{scroll-behavior:auto!important;transition:none!important}}

.image-open{display:block;width:100%;padding:0;cursor:zoom-in}.image-open img{max-height:360px;border-radius:5px}.graphic-card p{display:flex;justify-content:space-between;gap:10px;flex-wrap:wrap}.zoom-hint{font-size:9px;color:#9d8fc4}#imageDialog{border:0;border-radius:16px;padding:38px 18px 18px;max-width:min(96vw,1100px);max-height:94vh;background:white}#imageDialog::backdrop{background:#202337b8;backdrop-filter:blur(3px)}#zoomImage{max-width:100%;max-height:82vh;object-fit:contain;display:block;margin:auto}#closeImage{position:absolute;right:8px;top:5px;font-size:18px;width:32px;height:32px;color:#6e6688}

/* Mobile study layout: keep navigation and playback within easy reach. */
.mobile-title,.mobile-lesson-select{display:none}
@media(max-width:850px){
 .sidebar{display:none}.workspace{margin-left:0}
 header{height:52px;padding:0 20px}.header-right{font-size:10px}
 main{max-width:680px;padding:20px 20px 28px}
 .mobile-title{display:block;font-size:23px;letter-spacing:-.6px;margin:0 0 14px}
 .eyebrow,.title-row h1,.intro{display:none}
 .title-row{display:block}.overall{display:flex;align-items:center;gap:10px;border:0;padding:0;min-width:0}
 .overall strong{font-size:18px;white-space:nowrap}.overall strong span{font-size:13px}
 .overall small{font-size:12px;margin:0;white-space:nowrap;color:#666b7f}
 .progress-track{flex:1;margin:0 0 0 8px;height:6px}
 .mobile-select,.mobile-lesson-select{display:flex;align-items:center;gap:12px;font-size:13px;color:#62677b}
 .mobile-select{margin-top:18px}.mobile-select label,.mobile-lesson-select label{flex:0 0 76px}
 .mobile-select select,.mobile-lesson-select select{min-width:0;flex:1;width:100%;min-height:46px;padding:10px 12px;background:white;border:1px solid #dcdde7;border-radius:10px;color:var(--ink);font-size:16px}
 .part-tabs{margin:14px 0 16px;padding:4px;border:0;border-radius:12px;background:#eae7f4;gap:4px;justify-content:space-between}
 .part-tab{flex:1;min-height:44px;padding:10px 4px;justify-content:center;font-size:13px;color:#69617f}.part-tab span{display:none}
 .study-grid{display:block}.lesson-list{display:none}.mobile-lesson-select{margin-bottom:14px}
 .player-card{padding:16px;border-radius:18px}.player-top .icon-button{width:44px;height:44px;font-size:25px}
 .pill{font-size:10px}.player-heading{margin:2px 0 10px}.player-heading h2{font-size:26px}
 .player-heading p{font-size:12px;line-height:1.6;color:#746b87;margin:6px 0}.audio-art{display:none}
 .waveform{height:28px;margin:10px 0 0}.time-row{font-size:12px;margin-top:0;color:#766b89}
 #seek{height:28px;display:block;touch-action:pan-y}
 .controls{display:grid;grid-template-columns:1fr auto;gap:10px;margin-top:12px}
 .primary-controls{grid-column:1 / -1;grid-row:1;justify-content:space-between;gap:8px;max-width:330px;width:100%;margin:auto}
 .primary-controls .icon-button{width:48px;height:48px;font-size:20px;background:#ffffff80;color:#756493}
 .play-button{height:58px;width:58px;font-size:22px;flex-shrink:0}
 .speed-control select{min-height:44px;font-size:16px;padding:8px 12px;color:#655678;background:#fff9}
 .loop-button{min-height:44px;padding:8px 12px;color:#756493}.loop-button span{font-size:13px}
 .audio-status{font-size:12px;line-height:1.6}.audio-status:empty{display:none}
 .learning-tools{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:6px;padding:16px 0}
 .switch-label{position:relative;min-height:64px;flex-direction:column;justify-content:center;gap:8px;font-size:11px;color:#64697c;background:white;border:1px solid var(--border);border-radius:10px;text-align:center}
 .switch-label input{inset:0;width:100%;height:100%;margin:0;cursor:pointer}
 .switch{width:32px;height:18px;flex-shrink:0;pointer-events:none}.switch:before{width:14px;height:14px}
 .switch-label input:checked+.switch:before{transform:translateX(14px)}
 .switch-label:has(input:checked){border-color:#baaceb;background:#f2eefc;color:#6550b2}
 .content-card{padding:18px;min-height:0;border-radius:14px}.hidden-state{padding:4px 0 18px}.hidden-state .hidden-icon{display:none}
 .hidden-state h3{font-size:14px}.hidden-state p{font-size:12px}.text-label{font-size:11px;letter-spacing:.7px}
 .transcript,.translation{font-size:16px;line-height:1.85;color:#4f566b;overflow-wrap:anywhere}
 .question-title{font-size:15px;line-height:1.7}.answer-options{grid-template-columns:1fr;gap:9px}
 .answer-option{min-height:48px;padding:12px;font-size:14px;gap:10px;align-items:center}.answer-option .letter{font-size:12px;padding:4px 7px;flex-shrink:0}
 .key-result{font-size:13px;line-height:1.7}.graphic-card{padding:14px}.graphic-card p{font-size:12px;line-height:1.6;margin-top:0}.zoom-hint{font-size:11px}
 .lesson-actions{flex-wrap:wrap;gap:12px}.done-button{min-height:48px;flex:1;font-size:13px;padding:12px}
 .lesson-actions a{display:flex;align-items:center;min-height:44px;font-size:12px}
 .tips{font-size:13px;margin-top:20px}.tips summary{padding:10px 0;min-height:44px}.tips p,.source-note{font-size:13px;line-height:1.8}
 footer{max-width:680px;padding:16px 20px calc(24px + env(safe-area-inset-bottom));font-size:11px;gap:12px;flex-wrap:wrap}footer span{font-size:10px}
 #closeImage{width:44px;height:44px;top:0;right:0}#imageDialog{padding-top:48px}
}
@media(max-width:360px){
 main{padding:16px 12px 24px}header{padding:0 12px}.header-right{font-size:0}.avatar{font-size:12px}
 .player-card{padding:14px}.switch-label{font-size:10px}.mobile-title{font-size:22px}
 .lesson-actions{display:grid;grid-template-columns:1fr}.lesson-actions a{justify-content:center}
}