:root{font-family:Inter,Segoe UI,Arial,sans-serif;color:#18324b;background:#f3f6fa;font-synthesis:none;font-size:16px;--navy:#143657;--blue:#195b94;--line:#dce4ed;--muted:#61748a;--teal:#127e76;--amber:#95600b}
*{box-sizing:border-box}body{margin:0}button,input,textarea,select{font:inherit}button,a,input,textarea{outline-offset:4px}button{cursor:pointer}a{color:var(--blue);text-decoration:none}button:disabled{cursor:not-allowed;opacity:.5}h1,h2,h3,p{margin-top:0}h1{font-size:2rem;letter-spacing:-.04em;line-height:1.2;margin-bottom:.7rem}h2{font-size:1.25rem;line-height:1.4}h3{font-size:1rem}p{line-height:1.65}small{font-size:.8125rem;color:var(--muted)}button{border:0}.btn{display:inline-flex;align-items:center;justify-content:center;gap:.5rem;border:1px solid var(--line);border-radius:8px;padding:.65rem 1rem;background:white;color:var(--navy);font-size:.875rem;font-weight:650;min-height:40px}.btn:hover{background:#eef4fa}.btn.primary{background:var(--blue);color:white;border-color:var(--blue)}.btn.primary:hover{background:#154f82}.btn.green{background:var(--teal);color:#fff;border-color:var(--teal)}.btn.danger{color:#ae2a37}.btn.light{background:transparent;color:#fff;border-color:#56718b}.btn.small{padding:.4rem .7rem;min-height:34px}.muted{color:var(--muted)}.tag{padding:.3rem .6rem;border-radius:5px;background:#eaf0f6;font-size:.8125rem;display:inline-block;white-space:nowrap}.tag.warn{background:#fff0d0;color:#875508}.tag.good{background:#dff3ec;color:#116955}.tag.blue{background:#e7effa;color:#215b92}.eyebrow{text-transform:uppercase;font-weight:700;font-size:.75rem;letter-spacing:.12em;color:var(--muted);margin-bottom:.75rem}.row{display:flex;align-items:center;gap:.75rem;flex-wrap:wrap}.spread{justify-content:space-between}.stack{display:flex;flex-direction:column;gap:1rem}.panel{background:#fff;border:1px solid var(--line);border-radius:12px;padding:1.5rem}.section-head{display:flex;justify-content:space-between;align-items:flex-start;gap:1rem;margin-bottom:1.5rem}.section-head p{color:var(--muted);margin:0}.section-head h1{margin-bottom:.5rem}.empty{padding:3rem 1.5rem;text-align:center;border:1px dashed #c7d4e1;border-radius:12px;background:#fff}.empty h2{margin-bottom:.6rem}.empty p{color:var(--muted);margin-bottom:1.25rem}.grid{display:grid;grid-template-columns:repeat(auto-fit,minmax(min(100%,280px),1fr));gap:1.2rem}.notice{padding:1rem 1.1rem;background:#edf5fd;border:1px solid #d3e4f6;border-radius:8px;line-height:1.6;font-size:.875rem}.notice.warn{background:#fff7e7;border-color:#efd8a5;color:#785117}.notice.error{background:#fff0f1;border-color:#e9bfc4;color:#9a2030}.notice.good{background:#eef9f4;border-color:#c7e7d7;color:#14664b}.error-text{color:#ad2939;line-height:1.6;white-space:pre-line}.loading{padding:4rem;color:var(--muted)}.blank-space{height:1.5rem}
.shell{display:grid;grid-template-columns:240px 1fr;min-height:100vh}.sidebar{position:sticky;top:0;height:100vh;background:var(--navy);color:white;display:flex;flex-direction:column;padding:2rem 1.4rem}.brand{display:flex;align-items:center;gap:.8rem;color:white}.brand-mark{background:#245277;border:1px solid #406786;width:44px;height:44px;display:grid;place-items:center;border-radius:10px;font-family:monospace;font-size:1.5rem;font-weight:700;color:#9be7dc}.brand-title{font-size:1rem;font-weight:750}.brand-sub{font-size:.75rem;color:#b4c8da;margin-top:.3rem;line-height:1.4}.nav-label{font-size:.75rem;letter-spacing:.1em;color:#a9c1d4;text-transform:uppercase;margin:2.8rem 0 .8rem}.nav-link{display:flex;gap:.7rem;align-items:center;padding:.8rem 1rem;border-radius:7px;color:#e4edf5;font-size:.875rem;margin-bottom:.4rem;background:#224968}.side-note{margin-top:2rem;padding:1rem 0;border-top:1px solid #355574;color:#bcd0df;font-size:.875rem;line-height:1.65}.sidebar-bottom{margin-top:auto;padding-top:2rem}.user-name{font-weight:600;font-size:.875rem;margin:.8rem 0 .3rem;overflow-wrap:anywhere}.user-role{color:#bfd0e0;font-size:.8125rem;margin-bottom:1rem}.main{min-width:0}.topbar{height:74px;padding:0 2.5rem;display:flex;align-items:center;justify-content:space-between;border-bottom:1px solid var(--line);background:#fff;gap:1rem}.topbar small{font-size:.875rem}.content{max-width:1440px;margin:auto;padding:2.5rem}.class-card{padding:1.5rem;background:white;border:1px solid var(--line);border-radius:12px;display:flex;flex-direction:column;gap:1rem;box-shadow:0 4px 14px #17395405}.class-card h2{margin:.2rem 0}.class-card .class-icon{color:var(--teal);background:#e2f2ef;display:grid;place-items:center;width:44px;height:44px;border-radius:9px;font-size:1.25rem;font-family:monospace;font-weight:700}.card-meta{display:flex;gap:1.5rem;font-size:.875rem;color:var(--muted)}.class-code{font-family:monospace;letter-spacing:.12em;background:#edf3f9;color:#21496e;border-radius:4px;padding:.35rem .6rem}.stats{display:grid;grid-template-columns:repeat(3,1fr);gap:1rem;margin-bottom:1.7rem}.stat{padding:1.2rem 1.4rem;background:white;border:1px solid var(--line);border-radius:10px}.stat-value{font-size:1.9rem;font-weight:700;margin-top:.4rem}.stat-label{font-size:.875rem;color:var(--muted)}.table-wrap{overflow:auto;border:1px solid var(--line);border-radius:10px;background:white}table{width:100%;border-collapse:collapse;text-align:left;font-size:.875rem}th{background:#f8fafc;color:var(--muted);font-weight:600;padding:1rem;white-space:nowrap}td{padding:1rem;border-top:1px solid var(--line);vertical-align:middle}td strong{display:block;margin-bottom:.3rem}.tabs{display:flex;gap:.4rem;border-bottom:1px solid var(--line);margin-bottom:1.5rem}.tabs button{padding:.85rem 1rem;border-bottom:3px solid transparent;background:transparent;color:var(--muted);font-size:.875rem}.tabs button.active{border-color:var(--blue);color:var(--blue);font-weight:700}.assignment-card{display:flex;justify-content:space-between;align-items:center;gap:1rem}.assignment-card h2{margin-bottom:.5rem}.assignment-card p{margin:0;font-size:.875rem}.back{display:inline-flex;font-size:.875rem;color:var(--muted);margin-bottom:1.3rem}.instruction{white-space:pre-wrap;line-height:1.8;overflow-wrap:anywhere}.form-grid{display:grid;gap:1.2rem}.form-grid.two{grid-template-columns:1fr 1fr}.field{display:flex;flex-direction:column;gap:.5rem;font-size:.875rem;font-weight:600}.field input,.field textarea,.field select{font-weight:400;border:1px solid #c9d5e2;border-radius:7px;padding:.7rem .8rem;background:white;min-width:0;width:100%;color:#233c54}.field textarea{resize:vertical;line-height:1.6}.field small{font-weight:400;line-height:1.6}.form-actions{display:flex;justify-content:flex-end;gap:.7rem;margin-top:1.4rem}.monospace{font-family:Consolas,'Liberation Mono',monospace}.login-layout{min-height:100vh;display:grid;grid-template-columns:minmax(300px,.85fr) 1.15fr}.login-intro{background:var(--navy);color:white;padding:3rem 4rem;display:flex;flex-direction:column;justify-content:space-between}.login-intro h1{font-size:3rem;line-height:1.15;margin:3rem 0 1.5rem;max-width:380px}.login-intro p{color:#c5d7e5;max-width:390px}.intro-code{font:1rem/1.85 Consolas,monospace;border-top:1px solid #355674;border-bottom:1px solid #355674;padding:1.5rem 0;margin:2rem 0;color:#99dfd3;white-space:pre-wrap}.login-form-wrap{display:flex;align-items:center;justify-content:center;padding:3rem}.login-form{width:100%;max-width:440px}.login-form h2{font-size:1.8rem;letter-spacing:-.03em;margin-bottom:.6rem}.login-form .notice{margin:1.25rem 0}.login-foot{font-size:.8125rem;line-height:1.7;color:var(--muted);margin-top:1.5rem}.login-footer{font-size:.8125rem;color:#b4c8da}
.workspace{display:grid;grid-template-columns:minmax(0,1.65fr) minmax(260px,1fr);gap:1.25rem;align-items:start}.editor-panel{background:#11263c;border:1px solid #203c56;border-radius:10px;overflow:hidden}.editor-top{padding:.8rem 1rem;display:flex;align-items:center;justify-content:space-between;color:#d4e2ef;background:#1a354f;font-size:.875rem;gap:.8rem}.editor-file{font-family:monospace;color:#87e2d2}.editor-box{position:relative;height:420px;overflow:hidden;display:flex}.line-numbers{width:48px;flex:none;padding:1rem .6rem;color:#8294a7;background:#11263c;text-align:right;font:1rem/1.6 Consolas,'Liberation Mono',monospace;white-space:pre;overflow:hidden;user-select:none}.code-area{position:relative;flex:1;min-width:0;height:100%}.code-area textarea,.code-area pre{position:absolute;inset:0;border:0;margin:0;padding:1rem 1rem 1rem .6rem;tab-size:4;font:1rem/1.6 Consolas,'Liberation Mono',monospace;white-space:pre;overflow:auto;letter-spacing:normal;border-radius:0}.code-area pre{pointer-events:none;color:#dfe9f5}.code-area textarea{background:transparent;color:transparent;caret-color:#fff;resize:none;outline-offset:-3px;-webkit-text-fill-color:transparent}.code-area textarea::selection{background:#47678788}.tok-key{color:#c8a5fc}.tok-type{color:#78c6fb}.tok-string{color:#a1ddaa}.tok-comment{color:#819aad}.tok-num{color:#ffcc88}.editor-bottom{border-top:1px solid #2a4258;padding:.65rem 1rem;color:#a9bfd3;font-size:.8125rem;display:flex;justify-content:space-between;gap:.8rem}.io-panel{padding:1.25rem}.io-panel textarea{background:#f6f8fb;border:1px solid var(--line);border-radius:7px;padding:.8rem;width:100%;min-height:100px;resize:vertical;font:1rem/1.6 Consolas,monospace}.output{min-height:180px;max-height:320px;overflow:auto;font:1rem/1.6 Consolas,monospace;white-space:pre-wrap;word-break:break-word;margin:.8rem 0 0;background:#f6f8fb;padding:1rem;border-radius:7px;color:#243d53}.workspace-right{display:flex;flex-direction:column;gap:1rem}.save-status{font-size:.8125rem;color:#bfd3e5}.editor-actions{margin:1rem 0}.paste-alert{margin-bottom:1rem}.history-layout{display:grid;grid-template-columns:310px minmax(0,1fr);gap:1.2rem;align-items:start}.timeline{max-height:640px;overflow:auto;padding:.6rem;background:white;border:1px solid var(--line);border-radius:10px}.event-row{display:block;width:100%;padding:1rem;border-radius:7px;text-align:left;background:white;color:#263f57;border:1px solid transparent;margin-bottom:.3rem}.event-row:hover,.event-row.active{background:#eef4fb;border-color:#c6d9ec}.event-row.warning{border-left:3px solid #d8a437}.event-row strong{font-size:.875rem;display:block;margin-bottom:.35rem}.event-row small{display:block;line-height:1.6}.diff-grid{display:grid;grid-template-columns:1fr 1fr;gap:1rem}.diff-pane{min-width:0;border:1px solid var(--line);border-radius:8px;overflow:hidden}.diff-title{padding:.75rem 1rem;background:#f5f8fb;border-bottom:1px solid var(--line);font-size:.875rem;font-weight:650}.diff-code{font: .875rem/1.7 Consolas,monospace;margin:0;max-height:460px;overflow:auto;padding:.8rem 0;white-space:pre}.diff-line{display:block;min-height:1.7em;padding:0 .8rem}.diff-line.added{background:#e1f4e6;color:#225c35}.diff-line.removed{background:#ffe8ea;color:#982c3a}.code-num{display:inline-block;width:2.5rem;color:#7a8a9a;user-select:none}.history-help{font-size:.8125rem;line-height:1.7;color:var(--muted);margin:1rem 0}.hidden{display:none!important}#toast{position:fixed;bottom:24px;right:24px;max-width:400px;padding:1rem 1.3rem;border-radius:9px;background:#163b59;color:white;box-shadow:0 8px 30px #0c223533;z-index:50;display:none;font-size:.875rem;line-height:1.6}#toast.visible{display:block}dialog{border:1px solid var(--line);border-radius:14px;padding:1.8rem;max-width:700px;width:calc(100% - 2rem);max-height:90vh;overflow:auto;color:#18324b}dialog::backdrop{background:#122f4b80}.modal-title{display:flex;justify-content:space-between;align-items:center;margin-bottom:1.4rem}.modal-title h2{margin:0}.close{border:0;background:#edf2f7;width:32px;height:32px;border-radius:50%;font-size:1.3rem;color:#4c6378}.security-status{margin-top:1.5rem}
@media(min-width:1500px){.content{padding:3rem}.editor-box{height:480px}}@media(max-width:1100px){.shell{grid-template-columns:200px 1fr}.sidebar{padding:1.5rem 1rem}.content{padding:1.7rem}.topbar{padding:0 1.7rem}.workspace{grid-template-columns:1fr}.workspace-right{display:grid;grid-template-columns:1fr 1fr}.history-layout{grid-template-columns:250px minmax(0,1fr)}.diff-grid{grid-template-columns:1fr}.login-intro{padding:2.5rem}.login-intro h1{font-size:2.5rem}}@media(max-width:760px){.shell{grid-template-columns:1fr}.sidebar{position:static;height:auto;padding:1rem 1.2rem;flex-direction:row;align-items:center;justify-content:space-between;gap:1rem}.nav-label,.nav-link,.side-note,.sidebar-bottom .user-name,.sidebar-bottom .user-role{display:none}.sidebar-bottom{margin:0;padding:0}.brand-mark{width:38px;height:38px}.brand-sub{font-size:.75rem}.topbar{padding:.8rem 1.2rem;height:auto;min-height:54px}.content{padding:1.3rem 1rem}.section-head{flex-wrap:wrap}h1{font-size:1.7rem}.stats{gap:.5rem}.stat{padding:.8rem}.stat-value{font-size:1.5rem}.stat-label{font-size:.8125rem}.panel{padding:1.1rem}.assignment-card{align-items:flex-start;flex-direction:column}.workspace-right{display:flex}.history-layout{grid-template-columns:1fr}.timeline{max-height:250px}.login-layout{grid-template-columns:1fr}.login-intro{padding:1.4rem}.login-intro h1,.login-intro p,.intro-code,.login-footer{display:none}.login-form-wrap{padding:2rem 1.3rem}.form-grid.two{grid-template-columns:1fr}.editor-box{height:360px}.editor-top{flex-wrap:wrap}.diff-grid{grid-template-columns:1fr}.notice{font-size:.875rem}.form-actions{flex-wrap:wrap}#toast{right:1rem;left:1rem;bottom:1rem;max-width:none}}
.completion-popup{position:absolute;z-index:8;width:340px;max-width:calc(100% - 12px);background:#fff;border:1px solid #7f9cbb;border-radius:8px;box-shadow:0 8px 28px #0005;overflow:hidden;color:#1b3650}.completion-list{max-height:230px;overflow:auto;overscroll-behavior:contain}.completion-option{display:block;width:100%;padding:9px 12px;text-align:left;background:#fff;border:0;border-bottom:1px solid #edf1f6;color:#1b3650;min-height:56px}.completion-option[aria-selected=true]{background:#dceafb;box-shadow:inset 3px 0 #286fae}.completion-option:hover{background:#edf4fc}.completion-option-top{display:flex;align-items:center;justify-content:space-between;gap:12px}.completion-option strong{font:600 16px/1.4 Consolas,'Liberation Mono',monospace}.completion-option small{font:12px/1.4 'Segoe UI',sans-serif;color:#526e88}.completion-description{display:block;font:14px/1.45 'Segoe UI',sans-serif;margin-top:3px;white-space:normal;color:#486177}.completion-help{padding:8px 10px;background:#f0f4f8;border-top:1px solid #d9e3ee;font:12px/1.5 'Segoe UI',sans-serif;color:#536b81;white-space:normal}

/* Weekly teaching materials */
.tabs{flex-wrap:wrap}.materials-intro{margin-bottom:1.2rem}.materials-intro h2{margin:0 0 .5rem}.materials-intro p{font-size:.875rem;max-width:740px;margin:0;color:var(--muted);line-height:1.7}.materials-grid{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:1rem}.material-card{display:flex;flex-direction:column;gap:1rem;min-width:0}.material-card h3{font-size:1.1rem;line-height:1.5;margin:0;overflow-wrap:anywhere}.material-week{font-size:.8125rem;color:var(--muted);font-weight:600}.material-description{white-space:pre-wrap;overflow-wrap:anywhere;font-size:.875rem;line-height:1.7;margin:0}.material-card .muted{font-size:.875rem;margin:0}.material-actions{display:flex;gap:.65rem;flex-wrap:wrap;margin-top:auto}.material-check{display:flex;align-items:center;gap:.7rem;font-size:.875rem;line-height:1.6;cursor:pointer}.material-check input{width:18px;height:18px;accent-color:var(--blue)}@media(max-width:760px){.materials-grid{grid-template-columns:1fr}.material-check{min-height:44px}.materials-intro{align-items:flex-start}}