:root{--bg:#f5f7fb;--card:#fff;--ink:#172033;--muted:#6e7787;--line:#e2e6ef;--accent:#3157d5;--accent2:#243fa4;--danger:#b42318;--ok:#067647;--code:#0f172a}*{box-sizing:border-box}body{margin:0;background:var(--bg);color:var(--ink);font-family:Inter,"PingFang SC","Microsoft YaHei",system-ui,sans-serif}.topbar{height:64px;background:#101828;color:#fff;display:flex;align-items:center;justify-content:space-between;padding:0 4vw;position:sticky;top:0;z-index:20}.topbar a{color:#fff;text-decoration:none}.topbar nav{display:flex;gap:20px}.brand{font-weight:800}.container{width:min(1180px,92vw);margin:34px auto 80px}.hero{padding:70px 0 46px;max-width:760px}.hero h1,.page-title h1{font-size:clamp(32px,5vw,58px);margin:.2em 0}.hero p{font-size:18px;line-height:1.8}.eyebrow{letter-spacing:.16em;font-size:12px;font-weight:800;color:var(--accent);margin:0}.actions{display:flex;gap:12px;margin-top:28px}.btn{appearance:none;border:1px solid #c9d0dd;background:#fff;color:#27324a;border-radius:9px;padding:10px 16px;font-weight:700;cursor:pointer;text-decoration:none;display:inline-flex;align-items:center;justify-content:center}.btn:hover{background:#f8f9fc}.btn.primary{background:var(--accent);border-color:var(--accent);color:#fff}.btn.primary:hover{background:var(--accent2)}.btn.small{padding:6px 10px;font-size:12px}.btn.full{width:100%}.card{background:var(--card);border:1px solid var(--line);border-radius:14px;padding:24px;box-shadow:0 5px 20px rgba(16,24,40,.04);margin-bottom:22px}.card h2{margin-top:0}.grid{display:grid;gap:22px}.grid.two{grid-template-columns:repeat(2,minmax(0,1fr))}.grid.three{grid-template-columns:repeat(3,minmax(0,1fr))}.grid.compact{gap:10px}.narrow{max-width:460px;margin:80px auto}.auth h1{margin-top:0}label{display:flex;flex-direction:column;gap:8px;font-weight:700;margin-bottom:15px}input,textarea{width:100%;border:1px solid #cfd5df;border-radius:8px;padding:10px 12px;font:inherit;background:#fff;color:var(--ink)}textarea{resize:vertical;line-height:1.5}.inline-form{display:flex;align-items:end;gap:12px;flex-wrap:wrap}.inline-form label{margin:0}.inline-form input[type=file]{min-width:240px}.flash{padding:12px 16px;border-radius:9px;margin-bottom:16px;background:#eef2ff}.flash.error{background:#fef3f2;color:#912018}.flash.ok{background:#ecfdf3;color:#05603a}.page-title{display:flex;gap:28px;align-items:end;margin-bottom:24px}.page-title h1{font-size:38px;margin:.1em 0}.page-title h1 small{font-size:17px;color:var(--muted)}.stat{margin-left:auto;display:flex;flex-direction:column;align-items:center}.stat+ .stat{margin-left:0}.stat b{font-size:28px}.stat span,.muted{color:var(--muted)}.attendance-code{margin-top:18px;padding:18px;border:1px dashed #aab5c7;border-radius:10px;display:flex;align-items:center;gap:18px;flex-wrap:wrap}.attendance-code strong{font-size:36px;letter-spacing:.18em}.test-grid{display:grid;grid-template-columns:1fr 1fr 90px;gap:10px;align-items:center;margin-bottom:10px}.test-grid.head{color:var(--muted);font-size:13px}.check{display:flex;flex-direction:row;align-items:center;margin:0}.check input{width:auto}.table-wrap{overflow:auto}table{width:100%;border-collapse:collapse;font-size:14px}th,td{padding:11px 9px;border-bottom:1px solid var(--line);text-align:left}th{color:var(--muted);font-size:12px;text-transform:uppercase}.pill{display:inline-block;padding:3px 8px;border-radius:999px;background:#f2f4f7}.pill.ok{background:#ecfdf3;color:#067647}.problem-list{display:flex;flex-direction:column}.problem-row{padding:16px 4px;border-bottom:1px solid var(--line);display:flex;justify-content:space-between;gap:20px;text-decoration:none;color:inherit}.problem-row p{color:var(--muted);margin:6px 0 0}.problem-row span{white-space:nowrap;color:var(--accent);font-weight:700}.exam-banner{background:#fff0f0;color:#8f1717;border:1px solid #ffd0d0;border-radius:10px;padding:12px 16px;margin-bottom:14px;display:flex;gap:18px}.coding-grid{display:grid;grid-template-columns:minmax(320px,.8fr) minmax(480px,1.2fr);gap:18px;align-items:start}.statement{position:sticky;top:82px;max-height:calc(100vh - 100px);overflow:auto}.prewrap{white-space:pre-wrap;line-height:1.75}.limits{color:var(--muted);font-size:13px}.sample pre,pre{white-space:pre-wrap;overflow-wrap:anywhere;background:#f7f8fa;border:1px solid var(--line);padding:12px;border-radius:8px}.editor-card{padding:0;position:relative;overflow:hidden}.editor-toolbar{background:#111827;color:#cbd5e1;height:42px;display:flex;align-items:center;justify-content:space-between;padding:0 14px;font-size:13px}.editor-card textarea{border:0;border-radius:0;min-height:68vh;background:var(--code);color:#e5e7eb;font-family:"SFMono-Regular",Consolas,"Liberation Mono",monospace;font-size:14px;line-height:1.6;padding:18px;resize:none;outline:none}.editor-actions{padding:12px 14px;display:flex;justify-content:space-between;align-items:center;gap:10px}.lock-screen{position:absolute;inset:42px 0 0;background:rgba(15,23,42,.96);z-index:10;color:#fff;display:flex;align-items:center;justify-content:center;text-align:center;padding:30px}.lock-screen.hidden{display:none}.lock-screen p{max-width:480px;color:#cbd5e1}.result-grid{display:grid;grid-template-columns:repeat(3,1fr);gap:16px}.result-grid>div{background:#f8fafc;border:1px solid var(--line);border-radius:10px;padding:15px;display:flex;flex-direction:column}.result-grid span{color:var(--muted);font-size:12px}.result-grid strong{font-size:24px;margin-top:5px}.code-view{background:#0f172a;color:#e5e7eb}.sample{margin-bottom:16px}@media(max-width:850px){.grid.two,.grid.three,.coding-grid{grid-template-columns:1fr}.statement{position:static;max-height:none}.test-grid{grid-template-columns:1fr}.test-grid.head{display:none}.page-title{align-items:flex-start}.stat{margin-left:0}.exam-banner{flex-direction:column;gap:4px}.editor-card textarea{min-height:55vh}}
.run-panel{border-top:1px solid var(--line);padding:14px;background:#fbfcfe}.run-panel label{margin:0 0 8px;font-size:13px}.run-panel #stdin-text{min-height:110px;max-height:220px;resize:vertical;background:#fff;color:var(--ink);border:1px solid #cfd5df;border-radius:8px;font-family:"SFMono-Regular",Consolas,"Liberation Mono",monospace;font-size:13px}.run-actions{display:flex;align-items:center;gap:12px;margin-top:10px}.run-result{margin-top:12px;display:grid;gap:10px}.run-result.hidden,.result-box.hidden{display:none}.result-box{border:1px solid var(--line);border-radius:8px;background:#fff;padding:10px}.result-box b{font-size:12px;color:var(--muted)}.result-box pre{margin:7px 0 0;max-height:220px;overflow:auto;background:#0f172a;color:#e5e7eb;border:0;font-size:12px}.run-actions .muted{font-size:12px}
select{width:100%;border:1px solid #cfd5df;border-radius:8px;padding:10px 12px;font:inherit;background:#fff;color:var(--ink)}.section-title{display:flex;justify-content:space-between;gap:18px;align-items:center}.section-title h2{margin-bottom:4px}.compact-actions{margin-top:10px;flex-wrap:wrap}.btn.danger{color:#b42318;border-color:#f1b4ae}.metric-grid{display:grid;grid-template-columns:repeat(4,minmax(0,1fr));gap:16px;margin-bottom:22px}.metric{background:#fff;border:1px solid var(--line);border-radius:12px;padding:18px}.metric span{display:block;color:var(--muted);font-size:13px}.metric b{font-size:30px}.task-meta{display:flex;gap:36px;flex-wrap:wrap}.task-meta span{display:flex;flex-direction:column;gap:5px}.question-select{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:10px;margin:18px 0}.question-select label{border:1px solid var(--line);border-radius:10px;padding:12px;display:flex;flex-direction:row;align-items:flex-start;margin:0}.question-select input{width:auto;margin-top:3px}.question-select span{display:flex;flex-direction:column}.question-select small{color:var(--muted);margin-top:4px}.problem-row{align-items:center}@media(max-width:850px){.metric-grid,.question-select{grid-template-columns:1fr}.page-title{flex-wrap:wrap}.section-title{align-items:flex-start;flex-direction:column}.topbar{height:auto;min-height:64px;gap:16px}.topbar nav{flex-wrap:wrap;padding:10px 0}}
.batch-bar,.batch-tools{display:flex;gap:10px;align-items:center;flex-wrap:wrap;margin:12px 0 16px}.batch-bar select,.batch-tools select{width:auto;min-width:190px}.batch-tools input{width:auto;min-width:210px}.filter-grid{display:grid;grid-template-columns:repeat(4,minmax(150px,1fr));gap:12px;align-items:end}.filter-grid label{margin:0}.filter-actions{display:flex;gap:8px;flex-wrap:wrap;grid-column:1/-1}.table-wrap input[type=checkbox]{width:auto}.topbar nav{font-size:13px}.topbar nav a{white-space:nowrap}@media(max-width:900px){.filter-grid{grid-template-columns:1fr 1fr}.batch-tools input,.batch-tools select{width:100%}}@media(max-width:600px){.filter-grid{grid-template-columns:1fr}}
.judge-settings{margin:18px 0;padding:16px;border:1px solid var(--line);border-radius:12px;background:#f8fafc}.judge-settings h3{margin-top:0}.judge-settings small{font-weight:400}.notice{margin-top:16px;padding:14px;border-radius:10px;border:1px solid var(--line);background:#f8fafc}.notice.danger{border-color:#f4c7c3;background:#fff5f4;color:#8f1717}
.pill.danger{background:#fef3f2;color:#b42318}
/* V5 PPT canvas homework */
.canvas-workspace{display:grid;grid-template-columns:190px minmax(0,1fr);gap:16px;align-items:start}.canvas-sidebar{background:#fff;border:1px solid var(--line);border-radius:14px;position:sticky;top:82px;max-height:calc(100vh - 100px);overflow:auto}.canvas-side-head{padding:12px 14px;border-bottom:1px solid var(--line);display:flex;justify-content:space-between;color:var(--muted);font-size:12px}.canvas-thumbs{padding:10px;display:grid;gap:10px}.canvas-thumb{appearance:none;border:2px solid transparent;border-radius:9px;background:#f8fafc;padding:5px;cursor:pointer;color:var(--ink);text-align:left}.canvas-thumb.active{border-color:var(--accent);background:#eef2ff}.canvas-thumb img{width:100%;display:block;border-radius:5px;border:1px solid #d5dae3;background:#fff}.canvas-thumb span{display:block;padding:6px 4px 2px;font-size:12px}.canvas-main{min-width:0}.canvas-toolbar{background:#fff;border:1px solid var(--line);border-radius:12px;padding:9px;display:flex;gap:7px;align-items:center;flex-wrap:wrap;margin-bottom:9px}.canvas-toolbar .btn.active{background:#e9edff;border-color:#879cf0;color:#213fa8}.canvas-toolbar[aria-disabled=true]{opacity:.55;pointer-events:none}.canvas-mini{display:flex;flex-direction:row;align-items:center;gap:5px;margin:0;font-size:12px;color:var(--muted)}.canvas-mini input{width:60px;padding:5px}.canvas-mini input[type=color]{width:36px;height:30px;padding:2px}.canvas-info{display:flex;gap:16px;min-height:30px;align-items:center;flex-wrap:wrap;color:var(--muted);font-size:13px}.canvas-info b{margin-left:auto}.canvas-info [data-state=error]{color:var(--danger)}.canvas-info [data-state=ok]{color:var(--ok)}.canvas-stage-wrap{background:#d8dde8;border:1px solid #c9d0dd;border-radius:12px;padding:18px;overflow:auto}.canvas-stage{position:relative;width:min(100%,1200px);margin:0 auto;background:#fff;box-shadow:0 10px 32px rgba(16,24,40,.16);line-height:0;user-select:none}.canvas-stage>img{display:block;width:100%;height:auto;pointer-events:none}.canvas-svg{position:absolute;inset:0;width:100%;height:100%;overflow:visible;line-height:normal}.canvas-svg.locked{pointer-events:none}.canvas-svg.editable{touch-action:none;cursor:crosshair}.canvas-svg.regions{pointer-events:none}.canvas-region rect{fill:rgba(49,87,213,.04);stroke:rgba(49,87,213,.48);stroke-width:1.4;stroke-dasharray:7 6;vector-effect:non-scaling-stroke}.canvas-region text{font-size:15px;fill:#3157d5;font-weight:700}.selected-object{filter:drop-shadow(0 0 3px rgba(49,87,213,.9));stroke:#3157d5!important}.teacher-layer text{paint-order:stroke;stroke:#fff;stroke-width:2px}.canvas-bottom-actions{display:flex;justify-content:space-between;align-items:center;gap:16px;margin-top:12px}.canvas-bottom-actions form{margin:0}.template-designer .canvas-toolbar label{display:flex;flex-direction:row;align-items:center;margin:0;gap:6px}.template-designer .canvas-toolbar input[type=checkbox]{width:auto}.template-designer .canvas-toolbar input{width:220px}.template-region rect{fill:rgba(49,87,213,.08);stroke:#3157d5;stroke-width:2;stroke-dasharray:6 5;vector-effect:non-scaling-stroke}.template-region text{font-size:15px;fill:#1939aa;font-weight:700}.template-region.selected rect{fill:rgba(220,38,38,.08);stroke:#dc2626}.grading-panel{margin:14px 0 0}.teacher-edit{cursor:crosshair}.task-type-badge{display:inline-block;border-radius:999px;padding:3px 8px;font-size:11px;font-weight:800;background:#eef2ff;color:#3157d5}.task-type-badge.canvas{background:#fff4e5;color:#a15c00}@media(max-width:950px){.canvas-workspace{grid-template-columns:1fr}.canvas-sidebar{position:static;max-height:none}.canvas-thumbs{grid-template-columns:repeat(4,minmax(100px,1fr));overflow:auto}.canvas-bottom-actions{align-items:flex-start;flex-direction:column}}@media(max-width:600px){.canvas-thumbs{grid-template-columns:repeat(2,minmax(100px,1fr))}.canvas-stage-wrap{padding:6px}.canvas-toolbar{gap:4px}.canvas-toolbar .btn{padding:6px 8px}}
.canvas-text-dialog{position:fixed;inset:0;background:rgba(15,23,42,.55);z-index:1000;display:flex;align-items:center;justify-content:center;padding:20px}.canvas-text-dialog-box{width:min(680px,94vw);background:#fff;border-radius:14px;padding:20px;box-shadow:0 20px 60px rgba(0,0,0,.28)}.canvas-text-dialog-box textarea{margin-top:12px;min-height:180px}.canvas-text-dialog-box .actions{justify-content:flex-end;margin-top:12px}

/* V5 utility */
.grid.four{grid-template-columns:repeat(4,minmax(0,1fr))}
@media(max-width:1100px){.grid.four{grid-template-columns:repeat(2,minmax(0,1fr))}}
@media(max-width:850px){.grid.four{grid-template-columns:1fr}}
.report-cover-preview{border-top:4px solid #0f172a}.report-cover-preview p{margin:.3rem 0 0}.report-item-row{cursor:default}.report-quick-card{background:linear-gradient(135deg,#f8fafc,#eef2ff)}

/* V5.4 Word-like canvas editor */
.canvas-word-tip{margin:0 0 12px;padding:10px 14px;border:1px solid #cbd5ff;border-radius:10px;background:#f5f7ff;color:#334155;font-size:13px;line-height:1.6}.canvas-word-tip strong{color:#1d4ed8}.canvas-toolbar-word{position:sticky;top:70px;z-index:14;box-shadow:0 5px 18px rgba(15,23,42,.07);align-items:stretch}.canvas-tool-group{display:flex;gap:5px;align-items:center;flex-wrap:wrap;padding:3px 7px;border-right:1px solid var(--line)}.canvas-tool-group:last-child{border-right:0}.canvas-toolbar .btn:disabled{opacity:.42;cursor:not-allowed}.canvas-toolbar [data-canvas-format].active{background:#dbe5ff;border-color:#6b86e8;color:#1939aa}.canvas-mini select{width:auto;min-width:94px;padding:5px 7px;border-radius:7px}.canvas-view-tools{margin-left:auto}.canvas-zoom-label{min-width:42px;font-size:12px;color:var(--muted);text-align:center}.canvas-help-inline{color:#64748b}.canvas-stage-wrap{min-height:520px;max-height:calc(100vh - 245px);padding:18px;overflow:auto;overscroll-behavior:contain;scrollbar-gutter:stable both-edges}.canvas-stage{width:1000px;height:562px;max-width:none;aspect-ratio:var(--canvas-aspect);flex:0 0 auto}.canvas-stage>img{width:100%;height:100%;object-fit:fill}.canvas-svg.editable[data-tool="select"]{cursor:default}.canvas-svg.editable[data-tool="text"]{cursor:text}.canvas-svg.editable[data-tool="pen"]{cursor:crosshair}.canvas-object{pointer-events:all}.canvas-selection-box{fill:none;stroke:#3157d5;stroke-width:1.5;stroke-dasharray:6 4;vector-effect:non-scaling-stroke;pointer-events:none}.canvas-resize-handle{fill:#fff;stroke:#3157d5;stroke-width:1.5;vector-effect:non-scaling-stroke;pointer-events:all}.canvas-resize-handle[data-resize-handle="nw"],.canvas-resize-handle[data-resize-handle="se"]{cursor:nwse-resize}.canvas-resize-handle[data-resize-handle="ne"],.canvas-resize-handle[data-resize-handle="sw"]{cursor:nesw-resize}.canvas-resize-handle[data-resize-handle="n"],.canvas-resize-handle[data-resize-handle="s"]{cursor:ns-resize}.canvas-resize-handle[data-resize-handle="e"],.canvas-resize-handle[data-resize-handle="w"]{cursor:ew-resize}.canvas-line-handle{fill:#fff;stroke:#3157d5;stroke-width:1.5;vector-effect:non-scaling-stroke;cursor:move;pointer-events:all}.canvas-inline-text-editor{position:absolute;z-index:12;margin:0;border:2px solid #3157d5;border-radius:3px;padding:5px;resize:none;outline:none;box-shadow:0 0 0 2px rgba(49,87,213,.12);overflow:auto;box-sizing:border-box;white-space:pre-wrap;overflow-wrap:anywhere;transform-origin:top left}.canvas-inline-text-editor:focus{box-shadow:0 0 0 3px rgba(49,87,213,.18)}.canvas-workspace.sidebar-collapsed{grid-template-columns:minmax(0,1fr)}.canvas-workspace.sidebar-collapsed>.canvas-sidebar{display:none}.canvas-workspace:fullscreen,.canvas-workspace.is-fullscreen,.canvas-workspace.canvas-focus-fallback{background:#eef2f7;padding:10px;grid-template-columns:180px minmax(0,1fr);gap:10px}.canvas-workspace:fullscreen .canvas-main,.canvas-workspace.is-fullscreen .canvas-main,.canvas-workspace.canvas-focus-fallback .canvas-main{height:calc(100vh - 20px);display:flex;min-height:0;flex-direction:column}.canvas-workspace:fullscreen .canvas-toolbar,.canvas-workspace.is-fullscreen .canvas-toolbar,.canvas-workspace.canvas-focus-fallback .canvas-toolbar{position:static;flex:0 0 auto;margin-bottom:6px}.canvas-workspace:fullscreen .canvas-info,.canvas-workspace.is-fullscreen .canvas-info,.canvas-workspace.canvas-focus-fallback .canvas-info{flex:0 0 auto}.canvas-workspace:fullscreen .canvas-stage-wrap,.canvas-workspace.is-fullscreen .canvas-stage-wrap,.canvas-workspace.canvas-focus-fallback .canvas-stage-wrap{max-height:none;min-height:0;flex:1}.canvas-workspace:fullscreen .canvas-sidebar,.canvas-workspace.is-fullscreen .canvas-sidebar,.canvas-workspace.canvas-focus-fallback .canvas-sidebar{top:10px;max-height:calc(100vh - 20px)}.canvas-workspace.canvas-focus-fallback{position:fixed;inset:0;z-index:1001;margin:0}.canvas-workspace.canvas-focus-fallback.sidebar-collapsed,.canvas-workspace:fullscreen.sidebar-collapsed{grid-template-columns:minmax(0,1fr)}.canvas-toolbar[aria-disabled=true]{opacity:1;pointer-events:auto}.canvas-toolbar[aria-disabled=true] [data-canvas-tool],.canvas-toolbar[aria-disabled=true] [data-canvas-action="delete"],.canvas-toolbar[aria-disabled=true] [data-canvas-action="duplicate"],.canvas-toolbar[aria-disabled=true] [data-canvas-action="undo"],.canvas-toolbar[aria-disabled=true] [data-canvas-action="redo"],.canvas-toolbar[aria-disabled=true] [data-canvas-format]{opacity:.38;pointer-events:none}.canvas-toolbar[aria-disabled=true] input[data-canvas-color],.canvas-toolbar[aria-disabled=true] input[data-canvas-width],.canvas-toolbar[aria-disabled=true] input[data-canvas-font],.canvas-toolbar[aria-disabled=true] select[data-canvas-font-family]{opacity:.45;pointer-events:none}
@media(max-width:1100px){.canvas-toolbar-word{top:64px}.canvas-view-tools{margin-left:0}.canvas-stage-wrap{max-height:none;min-height:420px}.canvas-help-inline{display:none}}
@media(max-width:700px){.canvas-page-title{display:none}.canvas-description{display:none}.canvas-word-tip{font-size:12px}.canvas-toolbar-word{position:static}.canvas-tool-group{border-right:0;border-bottom:1px solid var(--line);width:100%}.canvas-text-width-control{display:none}.canvas-stage-wrap{padding:6px;min-height:360px}.canvas-inline-text-editor{border-width:1px}.canvas-workspace:fullscreen,.canvas-workspace.is-fullscreen,.canvas-workspace.canvas-focus-fallback{grid-template-columns:minmax(0,1fr)}.canvas-workspace:fullscreen>.canvas-sidebar,.canvas-workspace.is-fullscreen>.canvas-sidebar,.canvas-workspace.canvas-focus-fallback>.canvas-sidebar{display:none}}


/* V5.6 HTTPS + ICP footer */
html{min-height:100%}body{min-height:100vh;display:flex;flex-direction:column}main.container{flex:1 0 auto}.site-footer{flex:0 0 auto;border-top:1px solid var(--line);background:#fff;color:var(--muted)}.site-footer-inner{width:min(1180px,92vw);margin:0 auto;padding:18px 0;text-align:center;font-size:13px;line-height:1.6}.icp-link{color:var(--muted);text-decoration:none}.icp-link:hover,.icp-link:focus-visible{color:var(--accent);text-decoration:underline;text-underline-offset:3px}