:root{font-family:-apple-system,BlinkMacSystemFont,"Segoe UI","PingFang SC","Hiragino Sans GB","Microsoft YaHei",sans-serif;color:#22332f;background:#f6f8f8;font-synthesis:none;color-scheme:light;--muted:#74817c;--line:#e2e9e6;--blue:#19765e;--accent:#19765e;--button-width:112px}
*{box-sizing:border-box}body{margin:0;line-height:1.6;-webkit-text-size-adjust:100%}a{color:var(--accent)}button,input,select,textarea{font:inherit}button,a,input{ -webkit-tap-highlight-color:transparent}a,button,input,textarea,select{outline-offset:4px}a:focus-visible,button:focus-visible,input:focus-visible,textarea:focus-visible,select:focus-visible{outline:3px solid #4a9c87}[hidden]{display:none!important}h1,h2,p{margin:0}h1{font-size:30px;font-weight:650;line-height:1.4;letter-spacing:-.02em}h2{font-size:19px;font-weight:650;line-height:1.5}.muted{color:var(--muted)}.small,.help{font-size:13px}.help{margin-top:7px}.eyebrow{display:block;font-size:12px;font-weight:650;letter-spacing:.14em;color:var(--accent);margin-bottom:7px}.sr-only{position:absolute;width:1px;height:1px;margin:-1px;padding:0;overflow:hidden;clip:rect(0,0,0,0);white-space:nowrap;border:0}
.site-header{min-height:88px;padding:16px 32px;display:grid;grid-template-columns:1fr auto 1fr;align-items:center;gap:22px;background:#fff;border-bottom:1px solid var(--line)}.brand{display:flex;gap:12px;align-items:center;text-decoration:none;color:inherit;justify-self:start}.brand-icon{display:grid;place-items:center;width:44px;height:44px;border-radius:13px;background:#dceee6;flex-shrink:0}.brand-icon img{width:29px;height:29px}.brand strong{display:block;font-size:17px;font-weight:650;line-height:1.5}.brand small{display:block;font-size:14px;color:var(--muted);letter-spacing:.08em}.site-nav{display:flex;gap:6px;justify-content:center}.site-nav a{padding:9px 18px;border-radius:9px;font-size:15px;text-decoration:none;color:#67776f;white-space:nowrap}.site-nav [aria-current]{color:var(--accent);font-weight:650;background:#edf5f1}.account{display:flex;align-items:center;justify-self:end;gap:14px;font-size:13px}.account>span{max-width:150px;overflow-wrap:anywhere}.account form{margin:0}
.shell{max-width:1200px;margin:0 auto;padding:42px 32px 64px}.page-heading{display:flex;align-items:center;justify-content:space-between;gap:20px;margin-bottom:26px}.page-heading p{font-size:14px;margin-top:6px}.page-heading h1{display:flex;gap:12px;align-items:center}.count-pill{font-size:13px;font-weight:550;color:var(--muted);background:#eaf0ed;border-radius:7px;padding:2px 9px;letter-spacing:0}.panel{background:#fff;border:1px solid var(--line);border-radius:16px;padding:28px}.panel-heading{display:flex;align-items:center;justify-content:space-between;gap:14px;margin-bottom:14px}.notice{border:1px solid #c4e3d7;background:#edf7f2;color:#225d46;padding:13px 17px;border-radius:10px;margin-bottom:20px;font-size:14px;overflow-wrap:anywhere}.notice-error{border-color:#efc9c6;background:#fff3f2;color:#a23e3e}
.download-app .button{display:inline-flex;justify-content:center;align-items:center;gap:6px;width:var(--button-width);min-width:var(--button-width);max-width:var(--button-width);height:42px;min-height:42px;max-height:42px;padding:0 10px;border:1px solid transparent;border-radius:9px;font-size:14px;font-weight:600;line-height:1.2;text-decoration:none;white-space:nowrap;cursor:pointer;flex-shrink:0;transition:background .15s,border-color .15s}.button.primary{background:var(--accent);color:#fff;border-color:var(--accent)}.button.secondary{background:#fff;color:#455c52;border-color:#dce5e0}.button.danger,.download-app .button.text-danger{background:#fff;color:#ad4646;border-color:#ebd9d9}.button:disabled{opacity:.55;cursor:wait}.button.primary:hover{background:#125e4a}.button.secondary:hover{background:#f0f6f2;border-color:#b8cfc2}.button.danger:hover,.button.text-danger:hover{background:#fff1ef}
input:not([type=checkbox]):not([type=radio]):not([type=hidden]):not([type=file]),select,textarea{border:1px solid #dce5e0;background:#fff;color:#22332f;border-radius:9px;min-height:44px;padding:10px 13px;max-width:100%;font-size:15px;line-height:1.5}input::placeholder,textarea::placeholder{color:#a0aaa5}input[type=checkbox],input[type=radio]{accent-color:var(--accent);width:18px;height:18px;margin:0;flex-shrink:0}label{font-size:14px;font-weight:550}label>input:not([type=radio]):not([type=checkbox]){display:block;width:100%;margin-top:8px}textarea{width:100%;resize:vertical}.stack{display:flex;flex-direction:column;gap:24px}.stack label{display:block}.stack label>input{font-weight:400}.filters{display:flex;align-items:center;gap:10px;margin-bottom:18px}.filters label{display:block}.filters .search{flex:1;max-width:440px}.filters input{margin-top:0!important;width:100%;min-height:42px!important}.filters select{min-width:140px;min-height:42px;padding-block:8px}.task-list{display:flex;flex-direction:column;gap:12px}.task-card{display:flex;align-items:center;gap:18px;padding:23px 24px;background:#fff;border:1px solid var(--line);border-radius:15px;min-width:0}.file-icon{display:grid;place-items:center;flex-shrink:0;width:48px;height:54px;border-radius:12px;color:#2f7b62;background:#edf5f0}.file-icon.external{color:#6d729d;background:#f0f0f8}.file-icon svg{width:25px;height:25px;fill:none;stroke:currentColor;stroke-width:1.6;stroke-linecap:round;stroke-linejoin:round}.task-content{flex:1;min-width:0}.task-content h2{overflow-wrap:anywhere}.file-detail{font-size:13px;color:#75827b;margin-top:5px;overflow-wrap:anywhere}.task-meta{display:flex;align-items:center;gap:8px;flex-wrap:wrap;margin-top:11px;font-size:12px}.badge,.class-chip,.status{display:inline-flex;align-items:center;padding:2px 8px;border-radius:5px;font-size:12px;background:#edf5f0;color:#3d775f;font-weight:500}.badge-external{color:#737698;background:#f1f1f8}.class-chip{color:#728178;background:#f2f5f3}.status.unknown{background:#fff0ed;color:#a44e45}.task-meta time{color:#9aa59f;font-variant-numeric:tabular-nums}.task-actions{display:flex;gap:8px;align-items:center;flex-wrap:wrap;justify-content:flex-end;max-width:352px}.task-actions form{margin:0}.empty-state{text-align:center;padding:56px 24px}.empty-state p{font-size:14px;margin:9px 0 18px}.empty-symbol{display:grid;place-items:center;margin:0 auto 18px;width:54px;height:54px;border-radius:15px;background:#eef5f1;color:#7da890;font-size:28px}.pagination{display:flex;justify-content:center;gap:20px;align-items:center;margin-top:28px;color:var(--muted);font-size:14px}
.editor-heading,.editor-form{max-width:800px;margin-left:auto;margin-right:auto}.editor-form{padding:30px}.editor-form fieldset{margin:0;padding:0;border:0;min-width:0}.editor-form legend{font-size:14px;font-weight:550;margin-bottom:12px}.legend-note{font-size:12px;color:var(--muted);font-weight:400;margin-left:9px}.source-choices{display:grid;grid-template-columns:1fr 1fr;gap:12px}.stack label.source-choice{display:flex;gap:12px;align-items:center;border:1px solid var(--line);padding:17px 18px;border-radius:11px;cursor:pointer}.source-choice:has(input:checked){background:#f0f7f3;border-color:#70ab94}.source-choice strong{display:block;font-size:15px;font-weight:600}.source-choice small{display:block;font-size:12px;color:var(--muted);font-weight:400;margin-top:2px}.upload-area{display:flex!important;flex-direction:column;align-items:center;justify-content:center;text-align:center;background:#fafcfb;border:1px dashed #c6d8cd;border-radius:12px;padding:22px;gap:5px;cursor:pointer;overflow-wrap:anywhere}.upload-area strong{font-size:14px}.upload-area .muted{font-size:12px;font-weight:400}.upload-symbol{font-size:26px;line-height:1.3;color:#81a692}.upload-area input[type=file]{font-size:13px;max-width:100%;margin:12px auto 0}.upload-area input::file-selector-button{border:1px solid #d1e0d7;background:#fff;border-radius:7px;padding:7px 12px;color:#3c6250;cursor:pointer}.selected-file{font-size:13px;color:var(--accent);max-width:100%;word-break:break-all}.current-file{display:flex;align-items:center;gap:10px;margin-bottom:12px;flex-wrap:wrap;font-size:13px}.current-file strong{font-weight:500;overflow-wrap:anywhere}.class-choices{display:flex;gap:10px;flex-wrap:wrap}.stack label.class-choice{display:flex;align-items:center;gap:9px;padding:12px 15px;border:1px solid var(--line);border-radius:9px;cursor:pointer}.class-choice:has(input:checked){border-color:#70ab94;background:#f0f7f3}.class-choice small{font-size:12px;color:var(--muted);font-weight:400}.form-actions{display:flex;justify-content:flex-end;gap:10px;padding-top:22px;border-top:1px solid var(--line)}.upload-progress{display:flex;align-items:center;gap:16px;font-size:13px;color:var(--muted)}.upload-progress progress{flex:1;width:100%;height:9px;accent-color:var(--accent)}
.login-page .site-header{display:flex;justify-content:flex-start}.login-page .shell{padding-top:72px}.login-panel{max-width:430px;margin:auto;padding:34px}.login-heading{margin-bottom:28px}.login-heading h1{font-size:25px}.login-heading p{font-size:13px;margin-top:8px}.login-panel .stack{gap:20px}.login-panel .button{align-self:flex-end;margin-top:5px}
.student-table{width:100%;border-collapse:collapse}.student-table th{text-align:left;background:#f7faf8;color:var(--muted);font-size:12px;font-weight:500}.student-table td{border-top:1px solid var(--line)}.student-identity strong,.student-identity small{display:block}.student-identity small{color:var(--muted)}.download-app .student-list-heading h2{font-size:19px}.download-app .student-filters select,.download-app .student-filters input,.download-app .student-import textarea{font-size:15px}.download-app .student-table .student-identity strong{font-size:16px}.download-app .student-batch-empty p{font-size:14px}.student-actions{gap:8px}.download-app .student-actions-cell{min-width:425px}.download-app .student-ban-form input{min-height:42px;height:42px;width:65px;font-size:14px}.download-app .student-ban-form .button{border-radius:0 9px 9px 0}.download-app .student-password code{font-size:14px;background:#f2f6f3}.download-app .student-table td{font-size:14px}.download-app .student-status .status{font-size:12px}.download-app .student-credentials{font-size:15px}.student-batch-icon{color:var(--accent)!important;background:#edf5f0!important}
@media(max-width:1000px){.site-header{padding-inline:24px;grid-template-columns:auto 1fr auto;gap:12px}.brand strong{font-size:15px}.site-nav a{padding-inline:12px}.task-actions{max-width:232px}.task-card{align-items:flex-start}.task-actions>.button:first-child{margin-left:120px}.task-actions>.button:only-child{margin-left:0}}
@media(max-width:760px){:root{--button-width:min(112px,calc((100vw - 88px)/3))}.site-header{padding:14px 18px;grid-template-columns:1fr auto;gap:12px}.site-nav{grid-column:1/-1;grid-row:2;justify-content:flex-start;border-top:1px solid #eff3f0;padding-top:11px}.brand-icon{width:38px;height:38px;border-radius:10px}.brand-icon img{width:25px;height:25px}.account{gap:9px}.account>span{max-width:80px;font-size:12px}.shell{padding:28px 18px 44px}h1{font-size:26px}.page-heading{gap:12px;margin-bottom:23px}.page-heading p{font-size:13px}.filters{flex-wrap:wrap;gap:8px}.filters .search{flex-basis:100%;max-width:none}.filters>label:not(.search){flex:1}.student-filters-bar .search{flex-basis:0;min-width:0}.filters select{width:100%}.task-card{padding:19px 17px;gap:13px;flex-wrap:wrap}.file-icon{width:39px;height:46px;border-radius:9px}.file-icon svg{width:22px}.task-content{flex-basis:calc(100% - 52px)}.task-content h2{font-size:17px}.task-meta{gap:6px}.task-actions{max-width:none;width:100%;margin-top:4px;padding-top:14px;border-top:1px solid #eff3f0;gap:8px;justify-content:flex-end}.task-actions>.button:first-child{margin-left:0}.task-actions form{flex-shrink:0}.editor-form{padding:22px 18px}.source-choices{grid-template-columns:1fr;gap:9px}.stack label.source-choice{padding:14px}.class-choices{gap:8px}.stack label.class-choice{padding:10px 12px}.editor-heading{align-items:flex-start}.panel{border-radius:13px}.login-page .shell{padding-top:44px}.login-panel{padding:28px 22px}.empty-state{padding:42px 20px}.download-app .student-actions-cell{min-width:0}.download-app .student-list-heading{padding:20px 18px}.download-app .student-filters{display:grid;grid-template-columns:1fr 1fr}.download-app .student-filters input,.download-app .student-filters select{min-width:0;width:100%;font-size:14px}.download-app .student-actions{gap:8px;flex-wrap:wrap}.download-app .student-ban-form{flex-wrap:nowrap}.download-app .student-actions .button{padding:0 8px}.student-batch .panel-heading{flex-wrap:wrap}}
@media(prefers-reduced-motion:reduce){*{transition:none!important}}
.student-header{grid-template-columns:1fr auto}
.admin-task-card{padding:14px 18px;gap:14px;align-items:center}.admin-task-card .file-icon{width:40px;height:44px;border-radius:10px}.admin-task-card .file-icon svg{width:22px;height:22px}.admin-task-card h2{font-size:17px}.admin-task-card .admin-task-details{margin-top:4px;gap:6px 8px}.admin-task-details .file-detail{margin:0;max-width:180px;overflow:hidden;text-overflow:ellipsis;white-space:nowrap;font-size:12px}.admin-task-details .file-size{color:var(--muted);white-space:nowrap}.admin-task-details .badge,.admin-task-details .class-chip,.admin-task-details time{white-space:nowrap}.admin-task-card .task-actions{max-width:none;flex-wrap:nowrap}.admin-task-card .task-actions>.button:first-child{margin-left:0}
@media(max-width:760px){.admin-task-card{padding:14px;gap:10px 12px}.admin-task-card .task-actions{margin-top:0;padding-top:10px}.admin-task-card .task-content{flex-basis:calc(100% - 52px)}.admin-task-details .file-detail{max-width:min(180px,100%)}}
.student-task-list,.student-filters-bar{max-width:900px;margin-left:auto;margin-right:auto}.student-task-list{gap:10px}.student-task-card{display:grid;grid-template-columns:minmax(0,1fr) auto;gap:16px;padding:16px 20px;align-items:center}.student-task-card .task-content h2{font-size:17px;overflow:hidden;text-overflow:ellipsis;white-space:nowrap}.student-task-card .task-meta{margin-top:5px;gap:10px}.student-task-card .task-actions{width:auto;max-width:none;margin:0;padding:0;border:0;flex-wrap:nowrap}.student-task-card .task-actions>.button:first-child{margin-left:0}
@media(max-width:760px){.student-task-card{padding:14px;gap:12px}.student-task-card .task-content h2{font-size:16px}.student-task-card .task-meta{gap:4px 10px}.student-task-card time{white-space:nowrap}}
.file-selection-actions{display:flex;justify-content:flex-end}.file-selection-actions .button{margin-top:12px}
.upload-area.drag-over{background:#edf7f1;border-color:var(--accent);border-style:solid;box-shadow:0 0 0 2px #d6ebe0}
.admin-header{grid-template-columns:minmax(0,1fr) auto minmax(0,1fr);gap:16px}.admin-header .site-nav{gap:8px}.admin-header .site-nav .button[aria-current]{background:#edf5f1;border-color:#c9ded3;color:var(--accent)}
.filters input,.filters select{height:46px;min-height:46px!important;max-height:46px;padding-top:0;padding-bottom:0}
@media(max-width:760px){.admin-header{grid-template-columns:minmax(0,1fr) auto;gap:12px}.admin-header .account{grid-column:2;grid-row:1}.admin-header .site-nav{grid-column:1/-1;grid-row:2;border-top:0;padding-top:0;justify-content:center}}