:root{--ink:#183b30;--muted:#667c72;--green:#197553;--line:#e1eae4;--soft:#f0f6f2;--bg:#f6f8f5;color:var(--ink);background:var(--bg);font:16px/1.6 -apple-system,BlinkMacSystemFont,"PingFang SC","Noto Sans CJK SC","Microsoft YaHei",sans-serif;font-synthesis:none}
*{box-sizing:border-box}body{margin:0}button,a,input,select{font:inherit}button{cursor:pointer}button:disabled{cursor:wait;opacity:.6}a{color:inherit;text-decoration:none}button,a,input,select{-webkit-tap-highlight-color:transparent}button:focus-visible,a:focus-visible,input:focus-visible,select:focus-visible,canvas:focus-visible{outline:3px solid #83b69a;outline-offset:4px}button{transition:background .16s,border-color .16s,box-shadow .16s}.ui-icon{width:21px;height:21px;stroke:currentColor;stroke-width:1.7;fill:none;flex-shrink:0}h1,h2,p{overflow-wrap:anywhere}h1{font-size:clamp(28px,3.2vw,40px);line-height:1.35;letter-spacing:-1.2px;margin:12px 0 14px;font-weight:760}h2{font-size:21px;line-height:1.45;margin:0 0 12px}p{margin:8px 0}.muted,.sub{color:var(--muted)}.sub{font-size:16px;line-height:1.8}.tiny{font-size:12px;line-height:1.8}.mini-label{font-size:12px;color:var(--muted);font-weight:500}.eyebrow{color:var(--green);font-size:12px;font-weight:700;letter-spacing:1px}.sr-only{position:absolute;width:1px;height:1px;padding:0;overflow:hidden;clip:rect(0,0,0,0);white-space:nowrap;border:0}
.shell{max-width:1180px;min-height:100dvh;margin:auto;padding-bottom:100px}header{height:90px;display:flex;align-items:center;justify-content:space-between;padding:18px 40px;border-bottom:1px solid var(--line)}.brand{display:flex;align-items:center;gap:11px;font-size:25px;font-weight:780;letter-spacing:-1px}.brand-mark{display:flex;align-items:center;justify-content:center;width:38px;height:38px;border-radius:12px;background:var(--green);color:white}.brand-mark svg{width:23px;height:23px}.desktop-caption{font-size:13px;color:var(--muted)}main{padding:24px 40px 46px;min-width:0}.page-intro{margin:12px 0 30px}.page-intro.compact{margin-bottom:26px}.panel{background:white;border:1px solid var(--line);border-radius:18px;padding:28px;min-width:0;box-shadow:0 4px 24px #233d2f03}.section-heading{display:flex;justify-content:space-between;align-items:center;gap:12px;margin-bottom:18px}.section-heading h2{margin:0}.capture-grid{display:grid;grid-template-columns:minmax(0,1.5fr) minmax(0,1fr);gap:24px;align-items:start}.capture-aside{display:grid;gap:20px}.service-status{display:flex;align-items:flex-start;gap:10px;background:var(--soft);padding:14px 16px;border-radius:11px;font-size:13px;margin:16px 0}.service-status strong{display:block;font-weight:650}.service-status p{font-size:12px;color:var(--muted);line-height:1.8;margin:3px 0 0}.status-dot{width:7px;height:7px;border-radius:50%;background:#4c9175;flex-shrink:0;margin-top:7px}.service-status[data-kind=offline]{background:#fff4ec}.service-status[data-kind=offline] .status-dot{background:#c08443}.upload{display:flex;width:100%;min-height:255px;align-items:center;justify-content:center;flex-direction:column;gap:7px;padding:26px;border:1.5px dashed #aac5b6;border-radius:14px;background:#fafdfb;color:var(--ink);margin:22px 0}.upload>.ui-icon{width:46px;height:46px;color:var(--green);margin-bottom:14px}.upload strong{font-size:20px}.upload span{font-size:14px;color:var(--muted)}.upload small{font-size:12px;color:var(--muted);margin-top:7px}.upload:hover,.drag-over{background:#f3fbf6;border-color:var(--green)}.drag-over{box-shadow:0 0 0 3px #a0cdb555}.privacy-note{display:flex;align-items:flex-start;gap:7px;font-size:12px;line-height:1.8;color:var(--muted);margin-top:18px}.privacy-note svg{width:16px;height:16px;margin-top:2px}.btn{display:flex;width:100%;align-items:center;justify-content:center;gap:9px;background:var(--green);border:1px solid var(--green);border-radius:11px;color:white;font-size:15px;font-weight:650;min-height:50px;margin:20px 0 8px;padding:12px 18px;text-align:center}.btn:hover{background:#105d41}.btn.outline{background:white;color:var(--green);border-color:#bfd4c7}.btn.outline:hover{background:var(--soft)}.small-button{display:inline-flex;align-items:center;justify-content:center;gap:7px;min-height:40px;padding:8px 12px;border:1px solid var(--line);border-radius:9px;background:white;color:var(--ink);font-size:13px;white-space:nowrap}.small-button:hover{background:var(--soft);border-color:#adc6b8}.text-button{border:0;background:transparent;color:var(--green);font-size:13px;min-height:40px;padding:8px}.text-button:hover{text-decoration:underline}.icon-button{border:0;background:var(--soft);border-radius:50%;width:36px;height:36px;color:var(--ink);font-size:24px;line-height:1}.sample-panel .eyebrow{display:block;margin-bottom:12px}.sample-panel h2{font-size:23px;letter-spacing:-.5px}.sample{display:block;width:100%;text-align:left;border:1px solid #d9e8df;border-radius:12px;padding:18px 20px;background:#f5faf7;color:var(--ink);margin:22px 0 14px}.sample:hover{border-color:var(--green)}.sample-answer{display:block;font-size:12px;color:var(--muted);margin-top:12px}.formula{font:italic 32px/1.7 Georgia,serif;display:block;margin-top:7px}.tips-panel{padding:22px 28px;background:transparent;box-shadow:none}.tips-panel h2{font-size:15px}.tips-panel ol{margin:0;padding-left:19px;font-size:13px;color:var(--muted);line-height:2.2}.footer{color:var(--muted);font-size:12px;text-align:center;margin-top:28px}.error{background:#fff3ef;color:#973f32;border:1px solid #f3d9d2;border-radius:10px;padding:14px 16px;font-size:14px;line-height:1.75;margin:16px 0}.error:empty{display:none}.note{background:var(--soft);padding:16px;border-radius:12px;color:#496758;line-height:1.8;font-size:13px;margin:20px 0}.photo-card{border:1px solid var(--line);border-radius:13px;overflow:hidden;margin-top:20px;background:#f7f9f7}.photo-preview{display:block;width:100%;height:280px;object-fit:contain;padding:18px}.photo-caption{padding:10px 14px;border-top:1px solid var(--line);display:flex;align-items:center;justify-content:space-between;gap:10px;background:white;font-size:12px;color:var(--muted)}.photo-caption>span:first-child{overflow:hidden;text-overflow:ellipsis;white-space:nowrap}.photo-actions{display:flex;gap:8px;flex-wrap:wrap;margin-top:12px}.upload-help{font-size:12px;margin-top:14px}.badge{display:inline-flex;align-items:center;font-size:11px;font-weight:600;line-height:1.5;border-radius:6px;padding:4px 8px;white-space:nowrap}.success{color:#207552;background:#eaf6ee}.neutral{color:#61776a;background:#eef3ef}.danger{color:#a34f42;background:#fbede9}
nav{position:fixed;z-index:5;bottom:0;left:50%;transform:translateX(-50%);width:100%;max-width:1180px;background:rgba(255,255,255,.97);border-top:1px solid var(--line);display:flex;justify-content:center;gap:75px;padding:12px 24px max(12px,env(safe-area-inset-bottom))}nav button{display:flex;align-items:center;justify-content:center;gap:8px;min-width:110px;min-height:40px;border:0;background:none;border-radius:9px;color:var(--muted);font-size:14px}nav svg{width:23px;height:23px;stroke:currentColor;stroke-width:1.6;fill:none}nav button:hover{background:var(--soft)}nav .selected{color:var(--green);font-weight:650;background:#f1f7f3}
.back{display:inline-flex;border:0;background:transparent;color:var(--green);padding:0 0 12px;font-size:13px;min-height:40px;margin-bottom:14px}.back:before{content:'←';margin-right:8px}.task-grid{display:grid;grid-template-columns:minmax(0,1.45fr) minmax(0,1fr);gap:24px;align-items:start}.progress-panel h1{font-size:25px;margin:10px 0 24px}.current-phase{display:flex;align-items:center;gap:16px;padding:20px 0 26px;border-bottom:1px solid var(--line);margin-bottom:28px}.current-phase h2{font-size:19px;margin:0 0 3px}.current-phase p{font-size:13px}.spinner{display:inline-block;width:28px;height:28px;border:2.5px solid #d6e7dc;border-top-color:var(--green);border-radius:50%;animation:spin 1s linear infinite;flex-shrink:0}@keyframes spin{to{transform:rotate(360deg)}}.steps{list-style:none;margin:0;padding:0}.step{display:flex;align-items:flex-start;gap:15px;padding:0 0 24px;position:relative}.step:after{content:'';width:1px;height:25px;background:var(--line);position:absolute;left:16px;top:36px}.step:last-child:after{display:none}.dot{display:flex;width:34px;height:34px;flex-shrink:0;border:1px solid #c6d5cb;border-radius:50%;align-items:center;justify-content:center;color:var(--muted);font-size:13px;background:white}.dot svg{width:17px;height:17px}.step strong{font-size:14px}.step small{display:block;color:var(--muted);font-size:12px;margin-top:2px}.step.done .dot{background:var(--green);border-color:var(--green);color:white}.step.active .dot{border:2px solid var(--green);color:var(--green);background:#eff8f3}.progress-actions{display:flex;align-items:center;gap:20px;border-top:1px solid var(--line);padding-top:8px}.progress-actions .btn{width:auto;flex:1}.waiting-panel h2{margin-top:13px;font-size:24px}.waiting-panel p{font-size:14px}.task-notice h2{font-size:21px}.loading-panel{display:flex;flex-direction:column;align-items:center;justify-content:center;gap:14px;padding:70px 20px;color:var(--muted);font-size:14px}.connection-panel{max-width:580px;margin:20px auto}
.history-toolbar{display:flex;justify-content:space-between;gap:18px;align-items:center;padding-bottom:22px;border-bottom:1px solid var(--line);margin-bottom:24px}.filters{display:flex;gap:4px;background:var(--soft);padding:4px;border-radius:10px}.filters button{border:0;background:transparent;border-radius:7px;padding:8px 14px;font-size:13px;color:var(--muted);white-space:nowrap}.filters button.selected{background:white;color:var(--green);box-shadow:0 2px 5px #173d2c0b}.search-field{max-width:240px;min-width:0}.search-field input{width:100%;height:41px;border:1px solid var(--line);border-radius:9px;background:#fcfdfc;padding:9px 13px;color:var(--ink);font-size:13px}.video-grid{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:18px}.video-card{display:block;text-align:left;padding:0;border:1px solid var(--line);border-radius:13px;overflow:hidden;background:white;color:var(--ink);min-width:0}.video-card:hover{border-color:#91b7a0;box-shadow:0 5px 20px #173d2c08}.video-thumb{display:flex;align-items:center;justify-content:center;aspect-ratio:16/9;background:#eef5f0;position:relative;color:#9cb7a7;overflow:hidden}.video-thumb>svg{width:38px;height:38px}.video-thumb img{width:100%;height:100%;object-fit:cover}.duration-label{position:absolute;right:9px;bottom:8px;background:#153b2bc9;color:white;font-size:11px;padding:2px 6px;border-radius:5px}.video-card-body{padding:15px}.video-card-body strong{display:block;font-size:16px;margin:9px 0 5px}.card-badges{display:flex;align-items:center;gap:9px}.history-note{margin-top:26px}.empty{text-align:center;padding:55px 14px;color:var(--muted)}.empty>svg{width:42px;height:42px;margin-bottom:16px;stroke:#91ae9e}.empty h2{font-size:19px;color:var(--ink)}.empty p{font-size:13px}.empty .btn{max-width:220px;margin:22px auto 0}.empty .small-button{margin-top:16px}.profile-grid{display:grid;grid-template-columns:1fr 1fr;gap:24px}
.result-grid{display:grid;grid-template-columns:minmax(0,1.65fr) minmax(0,1fr);gap:25px;align-items:start}.player-column{min-width:0}.player-frame{background:#102c21;border:1px solid #244d3a;border-radius:14px;overflow:hidden}video{display:block;width:100%;aspect-ratio:16/9;background:#102c21}.player-tools{display:flex;flex-wrap:wrap;align-items:center;gap:8px;margin:13px 0 24px}.player-tools .small-button{font-size:12px;min-height:37px;padding:7px 10px}.speed-label{display:flex;align-items:center;gap:6px;font-size:12px;color:var(--muted);background:white;border:1px solid var(--line);border-radius:9px;padding:2px 8px;min-height:37px}.speed-label select{font-size:12px;border:0;color:var(--ink);background:white;padding:5px 0;cursor:pointer}.lesson-heading{display:flex;align-items:center;justify-content:space-between;gap:12px;margin:23px 0 20px}.lesson-heading h1{font-size:28px;margin:7px 0 0}.lesson-heading .eyebrow{font-size:11px;letter-spacing:0;color:var(--muted)}.answer-card{display:flex;align-items:center;justify-content:space-between;gap:12px;padding:19px 21px;border:1px solid #d8e7dc;background:#edf6f0;border-radius:12px;margin-bottom:15px}.answer{font-size:25px;font-weight:730;color:var(--green);margin-top:3px;white-space:pre-wrap}.chapters-panel{padding:23px 20px}.chapters-panel h2{font-size:18px}.row{display:block;background:transparent;border:0;border-bottom:1px solid var(--line);width:100%;text-align:left;padding:20px 5px;color:var(--ink)}.step-result{display:flex;gap:11px;align-items:flex-start;border-radius:10px}.number{background:#eaf2ec;color:var(--green);border-radius:50%;width:29px;height:29px;display:flex;align-items:center;justify-content:center;flex-shrink:0;font-size:12px;font-weight:600}.step-result>span:last-child{flex:1;min-width:0}.chapter-top{display:flex;justify-content:space-between;align-items:start;gap:6px}.chapter-top strong{font-size:14px;font-weight:650;line-height:1.6}.chapter-time{color:var(--muted);font-size:11px;line-height:2}.step-result .muted{display:block;font-size:12px;line-height:1.8;margin-top:7px}.step-result:hover,.step-result.playing{background:#f1f7f3}.step-result.playing .number{color:white;background:var(--green)}.wide-player .result-grid{grid-template-columns:1fr}.wide-player .chapters-panel .chapter-list{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:16px}.wide-player .chapters-panel>.btn{max-width:250px;margin-left:auto}
.crop-dialog{width:min(780px,calc(100% - 32px));max-height:calc(100dvh - 32px);padding:24px;border:1px solid var(--line);border-radius:20px;color:var(--ink);background:white;overflow:auto;box-shadow:0 24px 80px #0a241a33}.crop-dialog::backdrop{background:#10271eaa;backdrop-filter:blur(3px)}.dialog-heading{display:flex;align-items:center;justify-content:space-between;gap:15px}.dialog-heading h2{font-size:23px;margin:4px 0 0}.crop-dialog>p{font-size:13px;margin:15px 0}.crop-stage{display:flex;align-items:center;justify-content:center;padding:14px;background:#eaf0ec;border-radius:12px;min-height:160px;overflow:hidden}.crop-canvas{display:block;max-width:100%;max-height:48dvh;width:auto;height:auto;touch-action:none;cursor:crosshair;border-radius:3px}.crop-tools{display:flex;align-items:center;gap:8px;margin-top:14px;flex-wrap:wrap}.crop-tools [data-size]{margin-left:auto;font-size:12px}.dialog-actions{display:flex;gap:12px;margin-top:17px}.dialog-actions .btn{margin:0}.dialog-actions .outline{flex:0 0 100px}
@media(min-width:850px){.shell{padding-top:10px}nav{bottom:20px;width:430px;gap:8px;padding:8px;min-height:60px;border:1px solid #dce6df;border-radius:16px;box-shadow:0 8px 30px #163b2d0e}nav button{flex:1;min-width:0}main{padding-top:28px}.page-intro{margin-top:10px}}
@media(max-width:849px){header{height:72px;padding:15px 24px}main{padding:20px 24px 35px}.brand{font-size:23px}.brand-mark{width:34px;height:34px;border-radius:10px}.desktop-caption{font-size:12px}.capture-grid,.task-grid,.profile-grid{grid-template-columns:1fr;gap:19px}.page-intro{margin:9px 0 25px}h1{font-size:30px}.panel{padding:23px}.capture-aside{gap:16px}.tips-panel{padding:15px 23px}.upload{min-height:225px}.video-grid{grid-template-columns:repeat(2,minmax(0,1fr))}.result-grid{grid-template-columns:minmax(0,1.45fr) minmax(0,1fr);gap:18px}.chapters-panel{padding:20px 15px}.player-tools{gap:6px}.chapter-top{display:block}.waiting-panel{padding:23px}.waiting-panel h2{font-size:21px}nav{gap:30px;justify-content:space-around;padding-top:9px}nav button{min-width:65px;flex-direction:column;gap:3px;font-size:12px;min-height:47px;background:transparent!important}.wide-player .chapters-panel .chapter-list{grid-template-columns:1fr}}
@media(max-width:620px){main{padding:19px 18px 30px}header{padding:14px 20px}.sub{font-size:14px}h1{font-size:29px}.eyebrow{font-size:11px}.capture-grid{gap:19px}.panel{padding:21px 19px;border-radius:15px}.section-heading h2{font-size:18px}.service-status{padding:12px;margin-top:13px}.upload{margin:18px 0;min-height:219px;padding:21px 12px}.upload strong{font-size:19px}.upload small{font-size:10px}.privacy-note{font-size:11px}.sample-panel h2{font-size:22px}.sample-panel .muted{font-size:13px}.tips-panel{background:transparent}.photo-preview{height:245px;padding:12px}.photo-actions .small-button{padding:8px 10px;font-size:12px}.photo-actions{gap:7px}.progress-panel h1{font-size:24px}.current-phase{padding-top:8px}.progress-actions{gap:12px}.waiting-panel{background:#eff5f0;border:0}.history-toolbar{flex-direction:column;align-items:stretch;gap:13px}.filters{justify-content:space-between}.filters button{flex:1}.search-field{max-width:none}.video-grid{grid-template-columns:1fr;gap:14px}.video-card{display:grid;grid-template-columns:120px minmax(0,1fr)}.video-thumb{height:100%;min-height:115px;aspect-ratio:auto}.video-card-body{padding:13px}.video-card-body strong{font-size:15px}.video-card-body .tiny{font-size:11px}.result-grid{grid-template-columns:1fr;gap:17px}.player-tools{margin:12px 0 22px;gap:7px}.player-tools .small-button,.speed-label{min-height:39px}.player-tools .small-button{font-size:11px}.lesson-heading h1{font-size:26px}.answer-card{padding:16px}.answer{font-size:24px}.chapters-panel{padding:21px 17px}.row{padding:18px 5px}.chapter-top{display:flex}.chapters-panel>.btn{margin-top:22px}.profile-grid>.panel>.muted{font-size:14px}.crop-dialog{padding:19px 15px;border-radius:16px;width:calc(100% - 20px);max-height:calc(100dvh - 20px)}.crop-stage{padding:8px}.crop-dialog>p{font-size:12px}.crop-tools .small-button{font-size:12px}.crop-tools [data-size]{font-size:10px}.dialog-heading h2{font-size:21px}}
@media(prefers-reduced-motion:reduce){*{scroll-behavior:auto!important;animation:none!important;transition:none!important}.spinner{border-top-color:var(--green);border-right-color:var(--green)}}