:root{font-family:Inter,"Microsoft YaHei",sans-serif;font-size:16px;color:#193348;background:#f4f7fb;line-height:1.6}*{box-sizing:border-box}body{margin:0}button,input,select,textarea{font:inherit}button{cursor:pointer;background:#fff;color:#28485f;border:1px solid #d0dce5;border-radius:9px;padding:9px 16px;transition:background .15s}button:hover{background:#edf4fa}button:disabled{opacity:.5;cursor:default}a{color:#176397;text-underline-offset:4px}button:focus-visible,input:focus-visible,textarea:focus-visible,select:focus-visible,a:focus-visible,summary:focus-visible{outline:3px solid #d79929;outline-offset:3px}h1,h2,h3,h4,p{margin:0}h1{font-size:29px;letter-spacing:-.7px;line-height:1.45;margin:8px 0 12px}h2{font-size:20px}h3{font-size:18px}p{margin:8px 0;color:#536b7d}small{font-size:13px;color:#60758a;line-height:1.7}label{display:grid;gap:8px;font-weight:600;font-size:14px}input,textarea,select{width:100%;padding:11px 13px;color:#193348;background:#fff;border:1px solid #bfccd9;border-radius:9px;font-weight:400}textarea{resize:vertical;line-height:1.85;min-height:80px}select{cursor:pointer}.primary{background:#17658b;color:white;border-color:#17658b;font-weight:600}.primary:hover{background:#115374}.text-button{border-color:transparent;background:transparent;color:#17658b;font-size:14px;padding:5px 9px}.badge{display:inline-block;border-radius:5px;background:#e8f1f7;color:#285c7c;font-size:12px;padding:4px 9px;white-space:nowrap}.eyebrow{font-size:13px;letter-spacing:1px;color:#3c7792;margin-bottom:12px}.row{display:flex;gap:12px;align-items:center;justify-content:space-between}.row select{max-width:215px}.form-stack{display:grid;gap:18px}.form-two{display:grid;grid-template-columns:1fr 1fr;gap:18px}.card{border:1px solid #dce5ed;border-radius:15px;background:white;padding:26px}.card h3{margin:14px 0 8px}.notice,.global-notice{background:#fff5df;color:#735724;border:1px solid #eedba9;padding:14px 18px;border-radius:10px;font-size:14px}.global-notice{margin:16px 30px;display:flex;align-items:center;justify-content:space-between;gap:16px}.notice{margin:12px 0}.logo{display:flex;align-items:center;gap:12px;font-size:24px;color:white;font-weight:700}.logo>span{font-size:19px;letter-spacing:.3px}.app-shell{display:flex;min-height:100vh}.sidebar{width:236px;flex-shrink:0;padding:28px 19px;background:#122f45;color:#dce9f3;display:flex;flex-direction:column;gap:20px;position:sticky;top:0;height:100vh;overflow:auto}.side-caption{display:block;font-size:12px;letter-spacing:1px;color:#9cb4c8}.new-chat{background:#256180;color:white;border-color:#3d7795;text-align:left;padding:11px 15px}.new-chat:hover{background:#2e708f}.sidebar nav{display:grid;gap:5px}.sidebar nav button,.recent button{border:0;background:transparent;color:#c5d8e7;text-align:left;font-size:14px;padding:10px 13px}.sidebar nav button.active,.sidebar nav button:hover{background:#284b64;color:#fff}.sidebar nav .side-caption{margin:20px 12px 8px}.recent{display:grid;gap:6px;margin-top:10px}.recent button{white-space:nowrap;overflow:hidden;text-overflow:ellipsis;font-size:13px}.recent small{color:#9cb4c8}.profile{margin-top:auto;border-top:1px solid #365368;padding:18px 8px 0;display:grid;gap:4px}.profile small{color:#aac1d2}.profile button{background:transparent;color:#c5d8e7;border:0;text-align:left;padding:7px 0;font-size:13px}.main-area{flex:1;min-width:0}.topbar{height:72px;display:flex;align-items:center;justify-content:space-between;padding:0 34px;background:white;border-bottom:1px solid #dce5ed;font-size:14px}.section-page{max-width:1230px;margin:auto;padding:36px 40px 60px}.section-page>.card{margin:24px 0}.narrow{max-width:800px}.intro{font-size:16px;margin-bottom:28px}.task-grid{display:grid;grid-template-columns:repeat(4,1fr);gap:14px;margin:28px 0}.task-card{text-align:left;display:grid;gap:8px;padding:20px 17px;min-height:164px;border-radius:14px}.task-card strong{font-size:17px}.task-card small{font-size:13px}.task-symbol{color:#247a97;font-size:24px}.task-card.selected{background:#edf6fa;border:1px solid #4d96af;box-shadow:inset 0 0 0 1px #4d96af}.compose{display:grid;gap:17px}.compose>small{border-top:1px solid #edf1f5;padding-top:14px}.mode-tabs{display:flex;gap:10px;margin-bottom:4px}.mode-tabs button{flex:1;text-align:left;font-weight:600;padding:12px 16px}.mode-tabs button span{display:block;font-weight:400;font-size:13px;color:#617687;margin-top:3px}.mode-tabs button.selected{background:#eaf3f9;border-color:#337b9e;color:#16597a}.section-heading,.page-heading{display:flex;align-items:center;justify-content:space-between;gap:20px;margin:24px 0 18px}.source-grid{display:grid;grid-template-columns:1fr 1fr;gap:16px}.history-card{text-align:left;border-radius:13px;padding:22px;background:#fff}.history-card h3{margin:13px 0 15px;font-size:16px;line-height:1.65}.empty{padding:30px;color:#6a7f90;font-size:14px}.search{max-width:310px;font-size:14px}.file-button{position:relative;display:inline-block;border:1px solid #b9cfdd;border-radius:9px;padding:8px 15px;color:#17658b;cursor:pointer}.file-button input{position:absolute;inset:0;opacity:0;cursor:pointer;width:100%}.check{display:flex;align-items:center;gap:12px}.check input{width:18px;height:18px}.member{display:flex;align-items:center;justify-content:space-between;gap:20px;padding:18px 0;border-bottom:1px solid #e4ebf0}.member:last-child{border:0}.member p{font-size:13px}.studio{display:grid;grid-template-columns:minmax(0,1fr) 370px;min-height:calc(100vh - 72px)}.dialogue{padding:28px 28px 0;min-width:0;display:flex;flex-direction:column}.dialogue-head{padding-bottom:24px;border-bottom:1px solid #dbe5ed}.dialogue-head h1{font-size:21px;line-height:1.7}.dialogue-head .eyebrow{margin-bottom:6px}.messages{display:grid;gap:22px;padding:24px 0;align-content:start;min-height:240px}.message{padding:21px;border-radius:13px;border:1px solid #dfe8ef;background:#fff;min-width:0}.message span{font-size:12px;color:#647f93;font-weight:600}.user-message{background:#e7f0f7;border-color:#d8e4ed;margin-left:30px}.assistant-message{margin-right:16px}.rich-text{font-size:15px;line-height:1.95;overflow-wrap:anywhere}.rich-text p{white-space:pre-wrap;color:#203d51;margin:6px 0;min-height:8px}.rich-text h3{font-size:17px;margin:18px 0 9px}.reply-box{position:sticky;bottom:0;padding:16px 0 24px;background:#f4f7fb;margin-top:auto}.reply-box form{background:white;border:1px solid #cbdbe7;border-radius:13px;padding:12px}.reply-box textarea{border:0;min-height:85px}.reply-box small{font-size:12px}.artifact-panel{background:#fff;border-left:1px solid #dbe5ed;padding:28px 23px;display:flex;flex-direction:column;gap:16px;min-width:0}.artifact-panel>p{font-size:14px}.artifact-editor{min-height:440px;flex:1;font-size:14px}.artifact-actions{display:flex;gap:7px;flex-wrap:wrap}.artifact-actions button{font-size:13px;padding:8px 11px}.references{border-top:1px solid #dbe5ed;padding-top:16px;font-size:13px}.references article{border-bottom:1px solid #e3ebf1;padding:16px 0}.references h4{font-size:14px}.references p{max-height:260px;overflow:auto}.text-content{white-space:pre-wrap;overflow-wrap:anywhere;max-height:430px;overflow:auto;font-size:14px;line-height:1.9;margin-top:16px}.version{display:block;font-size:12px;margin:8px 0}summary{cursor:pointer;font-weight:600;line-height:1.8}.working{padding:18px;color:#17658b;font-size:14px}.sr-only{position:absolute;width:1px;height:1px;padding:0;overflow:hidden;clip:rect(0,0,0,0)}.loading-page{padding:80px;text-align:center}.auth-shell{min-height:100vh;display:grid;grid-template-columns:1fr 1fr;background:#fff}.auth-story{padding:60px;background:#122f45;color:white;display:flex;flex-direction:column}.auth-story .eyebrow{margin-top:110px;color:#83c0d5}.auth-story h1{font-size:37px;line-height:1.65;color:#fff}.auth-story p{color:#b9cedd}.auth-footer{margin-top:auto;color:#96b6cd;font-size:14px}.auth-form{align-self:center;padding:55px;max-width:580px;width:100%;margin:auto}.auth-form h2{font-size:28px;margin:20px 0 8px}.auth-form .form-stack{margin:30px 0}.auth-form>small{display:block;margin-top:25px}@media(min-width:1550px){.studio{grid-template-columns:minmax(0,1fr) 450px}.dialogue{padding:32px 60px 0}}@media(max-width:1150px){.sidebar{width:205px;padding:24px 14px}.task-grid{grid-template-columns:repeat(2,1fr)}.studio{grid-template-columns:minmax(0,1fr) 310px}.section-page{padding:30px 25px}.artifact-panel{padding:24px 16px}.dialogue{padding:25px 18px 0}.auth-story{padding:40px}}@media(max-width:900px){.studio{display:block}.artifact-panel{border-left:0;border-top:1px solid #dbe5ed}.artifact-editor{min-height:300px}.auth-story h1{font-size:28px}.auth-form{padding:30px}.auth-story{padding:30px}.auth-story .eyebrow{margin-top:80px}}@media(max-width:640px){.app-shell{display:block}.sidebar{position:static;width:100%;height:auto;padding:17px 18px;gap:12px}.sidebar nav{display:flex;flex-wrap:wrap}.sidebar nav .side-caption,.sidebar>.side-caption,.recent,.profile small{display:none}.sidebar nav button{padding:7px 10px;font-size:13px}.profile{margin:0;padding:10px 0 0;display:flex;align-items:center;justify-content:space-between}.logo{font-size:21px}.logo>span{font-size:18px}.new-chat{display:none}.topbar{height:56px;padding:0 18px}.section-page{padding:25px 18px 40px}h1{font-size:24px}.task-grid{gap:10px}.task-card{padding:15px 13px;min-height:145px}.source-grid,.form-two{grid-template-columns:1fr}.card{padding:19px}.mode-tabs{gap:8px}.mode-tabs button{padding:12px 10px;font-size:14px}.mode-tabs button span{font-size:12px}.row{flex-wrap:wrap}.compose .row select{max-width:180px}.page-heading{align-items:flex-start;flex-direction:column}.member{align-items:flex-start;flex-direction:column}.auth-shell{display:block}.auth-story{padding:25px}.auth-story .eyebrow{margin-top:30px}.auth-story h1{font-size:25px}.auth-story p:not(.eyebrow),.auth-footer{display:none}.auth-form{padding:30px 25px}.user-message{margin-left:14px}.assistant-message{margin-right:0}.message{padding:16px}.global-notice{margin:14px}.artifact-panel{padding:24px 18px}}

.entry-teacher .auth-story{background:#205a53}.entry-admin .auth-story{background:#193348}

.room-layout{display:grid;grid-template-columns:minmax(0,2fr) minmax(260px,1fr);gap:20px;margin-top:20px}.room-text{white-space:pre-wrap;overflow-wrap:anywhere}.room-messages{max-height:65vh;overflow:auto}.room-member{display:inline-flex;gap:8px;margin:8px 16px 8px 0;align-items:center}.room-member input{width:auto}.room-ai{margin-top:24px}.room-layout textarea{width:100%}@media(max-width:900px){.room-layout{grid-template-columns:1fr}}

.task-subnav{display:grid;gap:4px;padding:0 0 8px 12px;border-left:2px solid #3f6a7f;margin-left:10px}.task-subnav button{background:transparent;color:#c6dce9;border:0;text-align:left;padding:9px 12px;border-radius:7px;font-size:14px}.task-subnav button.active,.task-subnav button:hover{background:#2c5065;color:white}.new-chat span{float:right}@media(max-width:640px){.sidebar .new-chat{display:block}.task-subnav{grid-template-columns:repeat(2,minmax(0,1fr))}}

.video-panel{margin:20px 0}.video-item{padding:18px 0;border-top:1px solid #dbe5ed}.video-item textarea{width:100%}.video-item button{margin:10px 8px 10px 0}.video-panel .check{display:flex;align-items:flex-start;gap:10px;margin:14px 0}.video-panel .check input{width:auto;margin-top:7px}.video-panel small{display:block;overflow-wrap:anywhere}