:root{--bg: #f6f7fb;--panel: #ffffff;--text: #111827;--muted: #6b7280;--border: #e5e7eb;--primary: #111827;--primary-soft: #eef2ff;--accent: #4f46e5;--danger: #dc2626;--shadow: 0 20px 45px rgba(15, 23, 42, .08);font-family:Inter,ui-sans-serif,system-ui,-apple-system,BlinkMacSystemFont,Segoe UI,sans-serif}*{box-sizing:border-box}body{margin:0;background:var(--bg);color:var(--text)}button,input,textarea,select{font:inherit}button{cursor:pointer}.screen-center{min-height:100vh;display:grid;place-content:center;text-align:center;gap:14px}.loader{width:42px;height:42px;border:4px solid #e5e7eb;border-top-color:var(--accent);border-radius:50%;animation:spin .8s linear infinite;margin:auto}@keyframes spin{to{transform:rotate(360deg)}}.login-page{min-height:100vh;display:grid;grid-template-columns:1.2fr .8fr;align-items:center;gap:40px;padding:48px;background:radial-gradient(circle at 20% 20%,#dbeafe,transparent 32%),radial-gradient(circle at 80% 10%,#ede9fe,transparent 30%),#f8fafc}.login-hero h1{font-size:clamp(42px,6vw,82px);line-height:.95;margin:16px 0;letter-spacing:-3px}.login-hero p{max-width:680px;font-size:20px;color:var(--muted);line-height:1.6}.login-card,.panel,.post-card{background:#ffffffdb;border:1px solid rgba(255,255,255,.7);box-shadow:var(--shadow);border-radius:28px;padding:26px;-webkit-backdrop-filter:blur(16px);backdrop-filter:blur(16px)}.login-card{max-width:480px;width:100%}.login-card h2{margin:0 0 6px;font-size:30px}.hero-cards{display:flex;flex-wrap:wrap;gap:14px;margin-top:28px}.hero-cards div{display:flex;align-items:center;gap:10px;padding:14px 16px;border-radius:18px;background:#fff;box-shadow:var(--shadow)}.hero-cards svg{color:var(--accent)}.app-shell{min-height:100vh;display:grid;grid-template-columns:292px 1fr}.sidebar{position:sticky;top:0;height:100vh;background:#0f172a;color:#fff;padding:22px;display:flex;flex-direction:column;gap:24px}.brand{display:flex;align-items:center;gap:12px;cursor:pointer}.brand-logo{width:48px;height:48px;border-radius:17px;display:grid;place-items:center;background:linear-gradient(135deg,#6366f1,#22c55e);font-weight:900}.brand h1{font-size:20px;margin:0}.brand p{margin:2px 0 0;color:#cbd5e1}.nav-list{display:grid;gap:8px}.nav-item{border:0;border-radius:16px;padding:13px 14px;background:transparent;color:#cbd5e1;display:flex;align-items:center;gap:11px;text-align:left}.nav-item:hover,.nav-item.active{background:#ffffff1a;color:#fff}.sidebar-user{margin-top:auto;display:grid;grid-template-columns:42px 1fr 38px;gap:10px;align-items:center;background:#ffffff14;border-radius:18px;padding:12px}.avatar{width:42px;height:42px;border-radius:50%;background:#fff;color:#0f172a;display:grid;place-items:center;font-weight:800}.sidebar-user-text{min-width:0;display:grid}.sidebar-user-text strong{white-space:nowrap;overflow:hidden;text-overflow:ellipsis}.sidebar-user-text span{color:#cbd5e1;font-size:13px}.main-content{padding:32px;overflow:hidden}.mobile-topbar{display:none}.page{max-width:1180px;margin:0 auto;display:grid;gap:22px}.page-header,.welcome-card{display:flex;align-items:center;justify-content:space-between;gap:20px}.page-header h2,.welcome-card h2{font-size:clamp(30px,4vw,48px);margin:10px 0 6px;letter-spacing:-1.5px}.page-header p,.welcome-card p{margin:0;color:var(--muted);max-width:720px;line-height:1.6}.welcome-card{background:linear-gradient(135deg,#111827,#312e81);color:#fff;padding:32px;border-radius:30px;box-shadow:var(--shadow)}.welcome-card p{color:#d1d5db}.pill{display:inline-flex;align-items:center;gap:8px;padding:8px 12px;border-radius:999px;background:#eef2ff;color:#3730a3;font-weight:700;font-size:14px}.pill.dark{background:#ffffff1f;color:#fff}.muted{color:var(--muted)}.whitespace{white-space:pre-wrap}.primary-button,.secondary-button,.ghost-button,.danger-button,.link-button,.icon-button,.tiny-button,.mini-brand{border:0;border-radius:14px;display:inline-flex;align-items:center;justify-content:center;gap:8px;text-decoration:none}.primary-button{background:var(--primary);color:#fff;padding:12px 16px;font-weight:800}.primary-button:hover{transform:translateY(-1px)}.primary-button:disabled{opacity:.65;cursor:wait}.secondary-button{background:#eef2ff;color:#3730a3;padding:10px 13px;font-weight:700}.ghost-button{background:#f3f4f6;color:var(--text);padding:10px 13px}.danger-button{background:#fee2e2;color:var(--danger);padding:10px 13px;font-weight:800}.link-button{background:transparent;color:var(--accent);padding:8px;font-weight:800}.icon-button{width:36px;height:36px;background:#ffffff1a;color:inherit}.icon-button.danger{background:#fee2e2;color:var(--danger)}.tiny-button{font-size:12px;padding:5px 8px;background:#f3f4f6;color:var(--muted)}.form-stack{display:grid;gap:14px}.form-grid{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:14px}.span-2{grid-column:span 2}label{display:grid;gap:8px;font-weight:700;color:#374151}input,textarea,select{width:100%;border:1px solid var(--border);background:#fff;border-radius:16px;padding:13px 14px;outline:none}textarea{resize:vertical}input:focus,textarea:focus,select:focus{border-color:var(--accent);box-shadow:0 0 0 4px #4f46e51f}.checkbox-label{display:flex;flex-direction:row;align-items:center}.checkbox-label input{width:auto}.notice{padding:12px 14px;border-radius:16px;background:#ecfeff;color:#155e75;border:1px solid #a5f3fc}.stats-grid{display:grid;grid-template-columns:repeat(4,minmax(0,1fr));gap:16px}.stat-card{border:1px solid var(--border);background:#fff;border-radius:24px;padding:20px;text-align:left;display:grid;gap:10px;box-shadow:var(--shadow)}.stat-card svg{color:var(--accent)}.stat-card span{color:var(--muted);font-weight:700}.stat-card strong{font-size:32px}.stat-card.static{cursor:default}.two-column{display:grid;grid-template-columns:1fr 1fr;gap:18px}.panel-header{display:flex;align-items:center;justify-content:space-between;gap:14px}.panel h3{margin-top:0}.mini-row{padding:15px 0;border-top:1px solid var(--border);display:grid;gap:4px}.mini-row:first-of-type{border-top:0}.mini-row span{color:var(--muted)}.lesson-grid{display:grid;grid-template-columns:360px 1fr;gap:18px;align-items:start}.list-panel{display:grid;gap:12px}.lesson-card{text-align:left;border:1px solid var(--border);background:#f9fafb;border-radius:20px;padding:16px;display:grid;gap:7px}.lesson-card.active,.lesson-card:hover{border-color:#818cf8;background:#eef2ff}.lesson-card span{color:#6366f1;font-weight:800;font-size:13px}.lesson-card strong{font-size:18px}.lesson-card p{margin:0;color:var(--muted);line-height:1.45}.detail-panel{min-height:360px}.lesson-detail h3{font-size:30px;margin:0 0 8px}.content-box{background:#f9fafb;border:1px solid var(--border);border-radius:20px;padding:18px;line-height:1.7}.code-block,.output-panel pre,.submission-row pre{background:#0f172a;color:#e5e7eb;border-radius:20px;padding:18px;overflow-x:auto}.empty-state{display:grid;place-items:center;min-height:220px;color:var(--muted);text-align:center;border:1px dashed var(--border);border-radius:24px;background:#fafafa}.submission-box{margin-top:18px;display:grid;gap:12px}.submission-row{border-top:1px solid var(--border);padding:18px 0;display:grid;gap:10px}.submission-row>div:first-child{display:grid;gap:4px}.submission-row span{color:var(--muted)}.row-actions{display:flex;align-items:center;gap:10px}.feedback-chip{background:#dcfce7;color:#166534;border-radius:999px;padding:6px 10px;font-size:13px;font-weight:800}.post-list{display:grid;gap:16px}.post-header{display:flex;justify-content:space-between;gap:12px}.post-header h3{margin:0 0 5px}.post-header p{margin:0;color:var(--muted)}.comments{display:grid;gap:10px;margin-top:18px}.comment{background:#f9fafb;border-radius:16px;padding:12px;display:grid;gap:5px}.comment div{display:flex;gap:8px;align-items:center;color:var(--muted)}.comment p{margin:0}.comment-form{display:grid;grid-template-columns:1fr auto;gap:10px;margin-top:14px}.chat-layout{display:grid;grid-template-columns:300px 1fr;gap:18px;min-height:620px}.student-list{display:flex;flex-direction:column;gap:8px}.student-list button{border:0;background:#f9fafb;border-radius:16px;padding:12px;text-align:left;font-weight:700}.student-list button.active,.student-list button:hover{background:#eef2ff;color:#3730a3}.chat-panel{display:grid;grid-template-rows:1fr auto;min-height:620px}.chat-messages{overflow-y:auto;display:flex;flex-direction:column;gap:12px;padding-right:5px}.bubble{max-width:74%;background:#f3f4f6;border-radius:20px 20px 20px 4px;padding:12px 14px;align-self:flex-start}.bubble.mine{background:#111827;color:#fff;border-radius:20px 20px 4px;align-self:flex-end}.bubble p{margin:5px 0;white-space:pre-wrap}.bubble span{font-size:12px;opacity:.7}.chat-input{display:grid;grid-template-columns:1fr auto;gap:10px;padding-top:14px;border-top:1px solid var(--border)}.runner-grid{display:grid;grid-template-columns:1fr 1fr;gap:18px;min-height:560px}.editor-panel,.output-panel{display:grid;grid-template-rows:auto 1fr}.editor-panel textarea{min-height:480px;font-family:ui-monospace,SFMono-Regular,Menlo,Monaco,Consolas,monospace;line-height:1.55;background:#0f172a;color:#e5e7eb;border-color:#1f2937}.output-panel pre{min-height:480px;white-space:pre-wrap;margin:0}.table-wrap{overflow-x:auto}table{width:100%;border-collapse:collapse}th,td{text-align:left;border-bottom:1px solid var(--border);padding:13px}th{color:var(--muted);font-size:13px;text-transform:uppercase;letter-spacing:.04em}@media (max-width: 980px){.login-page{grid-template-columns:1fr;padding:24px}.app-shell{grid-template-columns:1fr}.sidebar{position:static;height:auto;border-radius:0 0 26px 26px}.nav-list{grid-template-columns:repeat(2,1fr)}.sidebar-user{display:none}.main-content{padding:20px}.mobile-topbar{display:flex;justify-content:space-between;margin-bottom:18px}.mini-brand{padding:10px 12px;background:#111827;color:#fff;font-weight:900}.stats-grid,.two-column,.lesson-grid,.runner-grid,.chat-layout,.form-grid{grid-template-columns:1fr}.span-2{grid-column:span 1}}@media (max-width: 620px){.nav-list{grid-template-columns:1fr}.page-header,.welcome-card{align-items:stretch;flex-direction:column}.stats-grid{grid-template-columns:1fr 1fr}.comment-form,.chat-input{grid-template-columns:1fr}.bubble{max-width:94%}.login-hero h1{letter-spacing:-1px}}.course-page{max-width:1320px}.course-hero{display:flex;justify-content:space-between;gap:22px;align-items:center;overflow:hidden;position:relative}.course-hero:after{content:"";position:absolute;width:360px;height:360px;border-radius:50%;background:radial-gradient(circle,rgba(99,102,241,.16),transparent 68%);right:-130px;top:-160px;pointer-events:none}.course-hero h2{font-size:clamp(34px,5vw,64px);margin:12px 0 8px;letter-spacing:-2px}.course-hero p{margin:0;max-width:720px;color:var(--muted);line-height:1.65;font-size:17px}.course-hero-stats{display:grid;grid-template-columns:repeat(3,minmax(82px,1fr));gap:12px;min-width:310px;position:relative;z-index:1}.course-hero-stats div{background:#0f172a;color:#fff;border-radius:22px;padding:18px 16px;display:grid;gap:4px;text-align:center}.course-hero-stats strong{font-size:28px}.course-hero-stats span{color:#cbd5e1;font-size:13px;font-weight:800}.course-shell{display:grid;grid-template-columns:340px 1fr;gap:20px;align-items:start}.course-sidebar{position:sticky;top:28px;display:grid;gap:16px}.course-sidebar-title{display:flex;align-items:center;gap:9px;font-weight:900;color:#111827}.course-search{display:grid;grid-template-columns:20px 1fr;align-items:center;gap:9px;border:1px solid var(--border);background:#f9fafb;border-radius:16px;padding:0 12px}.course-search input{border:0;box-shadow:none;background:transparent;padding-left:0}.course-search input:focus{box-shadow:none}.section-list{display:grid;gap:10px}.section-card{border:1px solid var(--border);background:#fff;border-radius:20px;padding:13px;display:grid;grid-template-columns:42px 1fr 20px;gap:11px;align-items:center;text-align:left;transition:.18s ease}.section-card:hover{transform:translateY(-1px);border-color:#a5b4fc;box-shadow:0 12px 28px #4f46e514}.section-card.active{background:#111827;color:#fff;border-color:#111827}.section-card.active small{color:#cbd5e1}.section-card.active .section-number{background:#fff;color:#111827}.section-number{width:42px;height:42px;display:grid;place-items:center;border-radius:15px;background:#eef2ff;color:#3730a3;font-weight:900}.section-main{display:grid;gap:3px;min-width:0}.section-main strong{white-space:nowrap;overflow:hidden;text-overflow:ellipsis}.section-main small{color:var(--muted);font-weight:800}.course-main{display:grid;gap:16px;min-width:0}.module-header-card{display:flex;align-items:center;justify-content:space-between;gap:18px;background:linear-gradient(135deg,#ffffffeb,#eef2ffeb)}.module-eyebrow{color:#4f46e5;font-weight:900;letter-spacing:.08em;text-transform:uppercase;font-size:12px}.module-header-card h3{margin:7px 0;font-size:32px;letter-spacing:-1px}.module-header-card p{margin:0;color:var(--muted);line-height:1.5}.lesson-roadmap{display:grid;gap:10px}.roadmap-item{width:100%;border:1px solid var(--border);background:#fff;border-radius:22px;padding:15px;display:grid;grid-template-columns:48px 1fr 28px;gap:14px;align-items:center;text-align:left;box-shadow:0 10px 24px #0f172a0a}.roadmap-item:hover,.roadmap-item.active{border-color:#818cf8;background:#eef2ff}.roadmap-index{width:48px;height:48px;border-radius:18px;display:grid;place-items:center;background:#0f172a;color:#fff;font-weight:900}.roadmap-body{display:grid;gap:5px;min-width:0}.roadmap-body strong{font-size:18px}.roadmap-body small{color:var(--muted);line-height:1.45}.roadmap-body em{font-style:normal;display:inline-flex;align-items:center;gap:5px;color:#4f46e5;font-size:13px;font-weight:800}.lesson-reader{padding:30px}.reader-topline{display:flex;flex-wrap:wrap;justify-content:space-between;gap:10px;color:#4f46e5;font-weight:900;font-size:13px;text-transform:uppercase;letter-spacing:.04em}.reader-topline span:first-child{display:inline-flex;align-items:center;gap:7px}.lesson-reader h3{font-size:clamp(30px,4vw,46px);letter-spacing:-1.5px;margin:12px 0 8px}.reader-description{color:var(--muted);line-height:1.65;font-size:17px;margin-top:0}.lesson-content-rich{border-top:1px solid var(--border);padding-top:18px;line-height:1.75}.lesson-content-rich h3{font-size:24px;margin:22px 0 10px;letter-spacing:-.4px}.lesson-content-rich h4{font-size:18px;margin:20px 0 8px}.lesson-content-rich p{margin:0 0 12px}.lesson-content-rich li{margin:4px 0 8px 18px}.example-section h4{display:flex;align-items:center;gap:8px;margin-bottom:10px}.practice-box{margin-top:16px;border:1px solid #bfdbfe;background:#eff6ff;border-radius:22px;padding:18px}.practice-box strong{display:block;color:#1d4ed8;margin-bottom:6px}.practice-box p{margin:0;line-height:1.55}.teacher-editor{border:2px dashed #c7d2fe}@media (max-width: 1100px){.course-shell{grid-template-columns:1fr}.course-sidebar{position:static}.section-list{grid-template-columns:repeat(2,minmax(0,1fr))}}@media (max-width: 760px){.course-hero{flex-direction:column;align-items:stretch}.course-hero-stats{min-width:0}.section-list{grid-template-columns:1fr}.module-header-card{flex-direction:column;align-items:stretch}.roadmap-item{grid-template-columns:42px 1fr}.roadmap-item>svg{display:none}.roadmap-index{width:42px;height:42px}.lesson-reader{padding:22px}}.vscode-card,.vscode-editor-card{overflow:hidden;border-radius:18px;border:1px solid #1f2937;background:#0d1117;box-shadow:0 18px 45px #02061738;margin:12px 0 18px}.vscode-card.compact{margin:6px 0;border-radius:14px;box-shadow:none}.vscode-titlebar{height:42px;display:grid;grid-template-columns:auto 1fr auto;align-items:center;gap:12px;padding:0 14px;background:#161b22;border-bottom:1px solid #263244;color:#c9d1d9;font-family:ui-monospace,SFMono-Regular,Menlo,Monaco,Consolas,Liberation Mono,monospace;font-size:13px}.vscode-dots{display:inline-flex;gap:7px;align-items:center}.vscode-dots span{width:11px;height:11px;border-radius:999px;display:block}.vscode-dots span:nth-child(1){background:#ff5f56}.vscode-dots span:nth-child(2){background:#ffbd2e}.vscode-dots span:nth-child(3){background:#27c93f}.vscode-file{color:#e5edf5;font-weight:800;white-space:nowrap;overflow:hidden;text-overflow:ellipsis}.vscode-lang{color:#7dd3fc;font-size:12px;font-weight:900;text-transform:uppercase;letter-spacing:.08em}.vscode-code{padding:12px 0;overflow-x:auto;background:linear-gradient(90deg,#0d1117 0,#0d1117);font-family:ui-monospace,SFMono-Regular,Menlo,Monaco,Consolas,Liberation Mono,monospace;font-size:14px;line-height:1.72}.vscode-line{display:grid;grid-template-columns:58px max-content;min-width:100%}.vscode-line:hover{background:#6366f114}.vscode-line-number{color:#6e7681;-webkit-user-select:none;user-select:none;text-align:right;padding-right:16px;border-right:1px solid rgba(110,118,129,.22)}.vscode-line-code{white-space:pre;color:#d4d4d4;padding-left:18px;padding-right:24px}.syntax-comment{color:#6a9955;font-style:italic}.syntax-string{color:#ce9178}.syntax-number{color:#b5cea8}.syntax-keyword{color:#c586c0;font-weight:800}.syntax-builtin{color:#4fc1ff}.syntax-variable{color:#dcdcaa}.syntax-operator{color:#d4d4d4}.syntax-punctuation{color:#8087a2}.syntax-plain{color:#d4d4d4}.vscode-editor-shell{display:grid;grid-template-columns:58px 1fr;background:#0d1117;max-height:none}.vscode-editor-gutter{padding:12px 0;background:#0d1117;border-right:1px solid rgba(110,118,129,.22);color:#6e7681;font-family:ui-monospace,SFMono-Regular,Menlo,Monaco,Consolas,Liberation Mono,monospace;font-size:14px;line-height:1.72;-webkit-user-select:none;user-select:none}.vscode-editor-gutter span{display:block;height:24.08px;padding-right:16px;text-align:right}.vscode-editor-shell textarea,.editor-panel .vscode-editor-shell textarea,.submission-box .vscode-editor-shell textarea,.form-grid .vscode-editor-shell textarea{border:0;border-radius:0;box-shadow:none;resize:vertical;min-height:220px;width:100%;padding:12px 18px;background:#0d1117;color:#d4d4d4;caret-color:#fff;font-family:ui-monospace,SFMono-Regular,Menlo,Monaco,Consolas,Liberation Mono,monospace;font-size:14px;line-height:1.72;-moz-tab-size:4;tab-size:4;outline:none}.editor-panel .vscode-editor-shell textarea{min-height:480px}.vscode-editor-shell textarea::placeholder{color:#6e7681}.vscode-editor-shell textarea:focus{box-shadow:inset 0 0 0 1px #7dd3fc73}.code-block,.submission-row pre{display:none}.output-panel pre{background:#0d1117;color:#d4d4d4;border:1px solid #1f2937;border-radius:18px;padding:18px;overflow-x:auto;font-family:ui-monospace,SFMono-Regular,Menlo,Monaco,Consolas,Liberation Mono,monospace}label .vscode-editor-card{margin-top:8px}@media (max-width: 620px){.vscode-titlebar{grid-template-columns:auto minmax(0,1fr)}.vscode-lang{display:none}.vscode-line{grid-template-columns:44px max-content}.vscode-line-number{padding-right:10px}.vscode-line-code{padding-left:12px}.vscode-editor-shell{grid-template-columns:44px 1fr}.vscode-editor-gutter span{padding-right:10px}}.community-page{max-width:1380px}.community-shell{display:grid;grid-template-columns:460px 1fr;gap:20px;align-items:start}.community-left{display:grid;gap:18px;min-width:0}.community-compose{display:grid;gap:14px}.type-grid{display:flex;flex-wrap:wrap;gap:8px}.type-chip{border:1px solid var(--border);background:#f9fafb;border-radius:999px;padding:8px 10px;display:inline-flex;align-items:center;gap:6px;font-weight:800;color:#374151}.type-chip.active{background:#111827;color:#fff;border-color:#111827}.compose-helper{border:1px solid #c7d2fe;background:#eef2ff;border-radius:18px;padding:12px 14px;display:grid;gap:3px}.compose-helper strong{color:#3730a3}.compose-helper span{color:#4b5563;font-size:13px}.compact-form-grid{grid-template-columns:1fr 1fr}.community-list-panel{display:grid;gap:14px;position:sticky;top:28px}.community-post-list{display:grid;gap:10px;max-height:720px;overflow-y:auto;padding-right:4px}.community-post-item{width:100%;border:1px solid var(--border);background:#fff;border-radius:20px;padding:14px;display:grid;gap:6px;text-align:left;transition:.18s ease}.community-post-item:hover,.community-post-item.active{border-color:#818cf8;background:#eef2ff;transform:translateY(-1px)}.community-post-item strong{font-size:17px;color:#111827}.community-post-item small{color:var(--muted);line-height:1.4}.community-post-item em{display:inline-flex;align-items:center;gap:5px;color:#2563eb;font-style:normal;font-weight:800;font-size:13px}.post-type-dot,.post-type-pill{width:fit-content;border-radius:999px;font-weight:900;font-size:12px;letter-spacing:.02em}.post-type-dot{padding:5px 8px;background:#f3f4f6;color:#374151}.post-type-pill{display:inline-flex;padding:7px 10px;margin-bottom:8px}.post-type-dot.question,.post-type-pill.question{background:#dbeafe;color:#1d4ed8}.post-type-dot.code,.post-type-pill.code{background:#dcfce7;color:#166534}.post-type-dot.project,.post-type-pill.project{background:#fef3c7;color:#92400e}.post-type-dot.resource,.post-type-pill.resource{background:#ede9fe;color:#6d28d9}.post-type-dot.announcement,.post-type-pill.announcement{background:#fee2e2;color:#991b1b}.community-detail-panel{min-height:780px}.post-detail-header{display:flex;justify-content:space-between;gap:20px;align-items:flex-start;border-bottom:1px solid var(--border);padding-bottom:18px}.post-detail-header h3{font-size:clamp(30px,4vw,48px);letter-spacing:-1.4px;margin:0 0 8px}.post-detail-header p{margin:0;color:var(--muted)}.post-links-row{display:flex;flex-wrap:wrap;gap:10px;margin:18px 0}.linked-context-box{display:flex;flex-wrap:wrap;gap:10px;border:1px solid #bfdbfe;background:#eff6ff;border-radius:18px;padding:12px;margin-bottom:14px}.linked-context-box span{display:inline-flex;align-items:center;gap:6px;color:#1d4ed8;font-weight:800}.community-post-content{background:#f9fafb;border:1px solid var(--border);border-radius:22px;padding:18px;line-height:1.75;margin-top:14px}.community-code-section h4{display:flex;align-items:center;gap:8px;margin:22px 0 8px}.resource-preview{display:grid;grid-template-columns:20px 1fr;gap:8px;align-items:center;border:1px solid var(--border);background:#f8fafc;border-radius:16px;padding:12px;color:var(--muted);overflow-wrap:anywhere}.detail-comments{border-top:1px solid var(--border);margin-top:24px;padding-top:14px}.detail-comments h4{margin:0 0 8px}.empty-state.small{min-height:120px}.lesson-fullscreen{max-width:1060px;margin:0 auto;padding:clamp(24px,4vw,46px)}.lesson-fullscreen article{display:grid;gap:14px}.lesson-fullscreen h2{font-size:clamp(38px,6vw,72px);line-height:.98;letter-spacing:-2.4px;margin:14px 0 6px}.back-button{width:fit-content;margin-bottom:12px}.lesson-meta-row{display:flex;flex-wrap:wrap;gap:10px;margin:4px 0 10px}.lesson-meta-row span{display:inline-flex;align-items:center;gap:6px;padding:8px 11px;border-radius:999px;background:#eef2ff;color:#3730a3;font-weight:900;font-size:13px}.lesson-fullscreen .lesson-content-rich{font-size:17px;border-top:1px solid var(--border);margin-top:8px}.lesson-fullscreen .lesson-content-rich p{margin-bottom:16px}.last-seen-cell{display:grid;gap:3px}.last-seen-cell strong{font-size:14px;color:#111827}.last-seen-cell span{color:var(--muted);font-size:12px}.status-pill{display:inline-flex;align-items:center;gap:6px;border-radius:999px;padding:6px 9px;font-weight:900;font-size:12px}.status-pill:before{content:"";width:8px;height:8px;border-radius:50%;display:block}.status-pill.online{background:#dcfce7;color:#166534}.status-pill.online:before{background:#22c55e}.status-pill.offline{background:#f3f4f6;color:#6b7280}.status-pill.offline:before{background:#9ca3af}@media (max-width: 1180px){.community-shell{grid-template-columns:1fr}.community-list-panel{position:static}.community-post-list{max-height:none}}@media (max-width: 700px){.compact-form-grid{grid-template-columns:1fr}.post-detail-header{flex-direction:column}.community-detail-panel{min-height:0}.lesson-fullscreen h2{letter-spacing:-1.2px}}.app-shell{transition:grid-template-columns .22s ease}.app-shell.sidebar-collapsed{grid-template-columns:92px 1fr}.brand-row{display:flex;align-items:center;justify-content:space-between;gap:10px}.sidebar-toggle{width:38px;height:38px;border:1px solid rgba(255,255,255,.16);background:#ffffff14;color:#fff;border-radius:14px;display:grid;place-items:center;cursor:pointer}.sidebar-toggle:hover{background:#ffffff29}.sidebar-collapsed .sidebar{padding-left:16px;padding-right:16px}.sidebar-collapsed .brand{justify-content:center}.sidebar-collapsed .brand-copy,.sidebar-collapsed .nav-item span,.sidebar-collapsed .sidebar-user-text,.sidebar-collapsed .sidebar-section-title span,.sidebar-collapsed .sidebar-empty,.sidebar-collapsed .online-mini-user strong,.sidebar-collapsed .online-mini-user small{display:none}.sidebar-collapsed .brand-row{justify-content:center;flex-direction:column}.sidebar-collapsed .nav-item{justify-content:center;padding:13px}.sidebar-collapsed .sidebar-user{justify-content:center;grid-template-columns:1fr}.sidebar-collapsed .sidebar-user .avatar{margin:0 auto}.sidebar-collapsed .sidebar-user .icon-button{margin:8px auto 0}.sidebar-online-card{border:1px solid rgba(255,255,255,.12);border-radius:22px;padding:12px;background:#ffffff0f;display:grid;gap:10px;margin-top:auto}.sidebar-section-title{display:flex;align-items:center;gap:8px;color:#e5e7eb;font-weight:900;font-size:13px}.sidebar-empty{margin:0;color:#9ca3af;font-size:12px}.online-mini-list{display:grid;gap:8px}.online-mini-user{display:grid;grid-template-columns:8px 30px 1fr auto;align-items:center;gap:8px;color:#fff;min-width:0}.online-mini-user .avatar.tiny{width:30px;height:30px;font-size:11px;background:#eef2ff;color:#3730a3}.online-mini-user strong{min-width:0;white-space:nowrap;overflow:hidden;text-overflow:ellipsis;font-size:13px}.online-mini-user small{color:#9ca3af;font-weight:800;font-size:11px}.online-dot{width:8px;height:8px;border-radius:50%;display:inline-block;background:#22c55e;box-shadow:0 0 0 4px #22c55e29}.mobile-actions{display:flex;gap:8px;align-items:center}.dashboard-page{max-width:1420px}.dashboard-hero{align-items:center}.hero-action-group{display:flex;flex-wrap:wrap;gap:10px;justify-content:flex-end}.dashboard-stats .stat-card{min-height:150px}.progress-panel{display:grid;gap:14px}.progress-big{font-size:36px;color:#3730a3}.progress-track{height:14px;border-radius:999px;overflow:hidden;background:#e5e7eb}.progress-track span{display:block;height:100%;background:linear-gradient(90deg,#6366f1,#22c55e);border-radius:inherit;min-width:2%;transition:width .25s ease}.progress-actions{display:flex;align-items:center;justify-content:space-between;gap:16px;border:1px solid var(--border);border-radius:20px;padding:14px;background:#f9fafb}.progress-actions div{display:grid;gap:4px}.progress-actions span{color:var(--muted)}.dashboard-grid-3{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:18px}.dashboard-panel-card{min-height:270px}.clickable-row{width:100%;text-align:left;border:0;cursor:pointer}.clickable-row:hover{background:#eef2ff}.active-user-row strong{display:inline-flex;align-items:center;gap:8px}.roadmap-item.completed{border-color:#86efac;background:#f0fdf4}.roadmap-item.completed .roadmap-index{background:#dcfce7;color:#166534}.completed-reader-badge{background:#dcfce7!important;color:#166534!important}.lesson-navigation-row{display:flex;flex-wrap:wrap;justify-content:space-between;gap:10px;border-top:1px solid var(--border);padding-top:18px;margin-top:10px}.lesson-navigation-row button:disabled{opacity:.5;cursor:not-allowed}.quiz-box{border:1px solid #c7d2fe;background:#f8fafc;border-radius:26px;padding:18px;display:grid;gap:16px;margin-top:12px}.quiz-header{display:flex;justify-content:space-between;gap:14px;align-items:flex-start}.quiz-header h4{display:flex;align-items:center;gap:8px;margin:0 0 4px}.quiz-header p{margin:0;color:var(--muted)}.quiz-score{border-radius:999px;background:#fef3c7;color:#92400e;padding:8px 12px}.quiz-score.success{background:#dcfce7;color:#166534}.quiz-list{display:grid;gap:12px}.quiz-question{border:1px solid var(--border);background:#fff;border-radius:18px;padding:14px;display:grid;gap:10px}.quiz-question.correct{border-color:#86efac;background:#f0fdf4}.quiz-question.wrong{border-color:#fecaca;background:#fff1f2}.quiz-question small{color:#991b1b;font-weight:800}.quiz-options{display:grid;gap:8px}.quiz-options label{border:1px solid var(--border);background:#f9fafb;border-radius:14px;padding:10px 12px;display:flex;align-items:center;gap:9px;cursor:pointer}.quiz-options label.selected{border-color:#818cf8;background:#eef2ff;color:#3730a3;font-weight:900}.quiz-actions{display:flex;flex-wrap:wrap;gap:10px;justify-content:flex-end}.teacher-editor textarea[placeholder*=multiple_choice]{font-family:ui-monospace,SFMono-Regular,Menlo,Monaco,Consolas,monospace;font-size:13px;background:#0d1117;color:#d4d4d4;border-color:#1f2937}.community-filter-row{display:grid;grid-template-columns:20px 1fr 1fr;gap:8px;align-items:center}.community-filter-row select{padding:11px}.post-mini-badges{display:flex;flex-wrap:wrap;gap:7px}.post-mini-badges em{display:inline-flex!important}.post-mini-badges .solved{color:#166534}.community-post-item.pinned{border-color:#f59e0b;box-shadow:0 10px 24px #f59e0b1f}.post-admin-actions{display:flex;flex-wrap:wrap;gap:8px;justify-content:flex-end}.post-admin-actions .secondary-button{padding:10px 12px}@media (max-width: 1180px){.dashboard-grid-3,.app-shell.sidebar-collapsed{grid-template-columns:1fr}}@media (max-width: 980px){.sidebar-toggle,.sidebar-online-card{display:none}.progress-actions,.quiz-header{flex-direction:column;align-items:stretch}.community-filter-row{grid-template-columns:1fr}}@media (max-width: 700px){.hero-action-group,.lesson-navigation-row,.quiz-actions{justify-content:stretch}.hero-action-group button,.lesson-navigation-row button,.quiz-actions button{width:100%}}.live-chip{display:inline-flex;align-items:center;gap:8px;border:1px solid var(--border);background:#f8fafc;color:#64748b;padding:10px 13px;border-radius:999px;font-size:13px;font-weight:900;white-space:nowrap}.live-chip.online{border-color:#bbf7d0;background:#f0fdf4;color:#15803d}.chat-topbar{display:flex;align-items:center;justify-content:space-between;gap:12px;padding:14px 16px;border-bottom:1px solid var(--border);background:#f8fafc;border-radius:20px 20px 0 0}.chat-topbar div{display:grid;gap:3px}.chat-topbar span{color:var(--muted);font-size:13px;font-weight:700}.secondary-button.small{padding:8px 11px;font-size:13px;border-radius:12px}.student-list button span{overflow:hidden;text-overflow:ellipsis;white-space:nowrap}.chat-input button:disabled{opacity:.55;cursor:not-allowed}@media (max-width: 620px){.chat-topbar{align-items:stretch;flex-direction:column}.live-chip{justify-content:center}}.error-text{color:#dc2626!important;background:#fee2e2;border:1px solid #fecaca;border-radius:14px;padding:10px 12px}.messages-page{min-height:calc(100vh - 64px)}.messages-page .chat-layout{height:min(720px,calc(100vh - 230px));min-height:520px;align-items:stretch}.messages-page .student-list{min-height:0;max-height:100%;overflow-y:auto}.messages-page .chat-panel{display:grid;grid-template-rows:auto minmax(0,1fr) auto;height:100%;min-height:0;overflow:hidden;padding:0}.messages-page .chat-panel>.empty-state{grid-row:1 / -1;margin:18px;min-height:0}.messages-page .chat-messages{min-height:0;max-height:100%;overflow-y:auto;padding:18px 18px 12px;scroll-behavior:smooth}.messages-page .chat-input{padding:14px 16px 16px;background:#fffffff5}.messages-page .chat-messages::-webkit-scrollbar,.messages-page .student-list::-webkit-scrollbar{width:10px}.messages-page .chat-messages::-webkit-scrollbar-thumb,.messages-page .student-list::-webkit-scrollbar-thumb{background:#cbd5e1;border-radius:999px;border:2px solid transparent;background-clip:content-box}.messages-page .chat-messages::-webkit-scrollbar-track,.messages-page .student-list::-webkit-scrollbar-track{background:transparent}@media (max-width: 900px){.messages-page .chat-layout{height:auto;min-height:0}.messages-page .chat-panel{height:70vh;min-height:520px}}.avatar{overflow:hidden;flex:0 0 auto}.avatar span{display:grid;place-items:center;width:100%;height:100%}.avatar img{width:100%;height:100%;object-fit:cover;display:block}.avatar.small{width:38px;height:38px;font-size:13px}.avatar.profile-avatar{width:116px;height:116px;font-size:34px;border:6px solid white;box-shadow:0 18px 40px #0f172a24}.profile-grid{display:grid;grid-template-columns:360px 1fr;gap:18px;align-items:start}.profile-card-large{min-height:280px;display:grid;place-items:center;text-align:center;background:radial-gradient(circle at top,#eef2ff,#fff 58%)}.profile-card-large h3{margin:16px 0 4px;font-size:28px;letter-spacing:-.8px}.profile-card-large p{margin:0;color:var(--muted);font-weight:800}.profile-settings-card,.profile-readonly-card{display:grid;gap:14px}.profile-actions{display:flex;flex-wrap:wrap;gap:10px}.profile-readonly-card input:disabled{background:#f8fafc;color:#475569;opacity:1}.user-inline{display:inline-flex;align-items:center;gap:9px;min-width:0}.user-inline strong{overflow:hidden;text-overflow:ellipsis;white-space:nowrap}.admin-user-cell{display:flex;align-items:center;gap:10px;min-width:190px}.admin-user-cell>div:last-child{display:grid;gap:2px;min-width:0}.admin-user-cell strong{white-space:nowrap;overflow:hidden;text-overflow:ellipsis}.admin-user-cell span{color:var(--muted);font-size:12px}.inline-edit{display:grid;grid-template-columns:minmax(170px,1fr) auto;gap:8px;min-width:310px}.inline-edit input{padding:10px 12px;border-radius:12px}.secondary-button.small,.danger-button.small{padding:9px 11px;border-radius:12px;font-size:13px;white-space:nowrap}.secondary-button:disabled,.danger-button:disabled{opacity:.45;cursor:not-allowed;transform:none}.avatar-admin-actions{display:flex;align-items:center;gap:9px;min-width:150px}.admin-user-table td{vertical-align:middle}.student-list button,.chat-topbar-user{display:flex;align-items:center;gap:10px}.chat-topbar-user>div{display:grid;gap:2px}.bubble-author{display:flex;align-items:center;gap:8px}.bubble.mine .bubble-author .avatar{background:#ffffff29;color:#fff}@media (max-width: 980px){.profile-grid{grid-template-columns:1fr}.inline-edit{min-width:250px}}@media (max-width: 620px){.profile-actions{display:grid}.inline-edit{grid-template-columns:1fr;min-width:220px}}.runnable-code-block{display:grid;gap:10px;margin:14px 0 18px}.inline-lesson-code{margin:18px 0}.code-actions-row{display:flex;flex-wrap:wrap;gap:9px;align-items:center;margin-top:-4px}.code-output-card{overflow:hidden;border-radius:16px;border:1px solid #1f2937;background:#020617;box-shadow:0 10px 28px #0206172e}.code-output-title{padding:9px 13px;background:#111827;border-bottom:1px solid #263244;color:#93c5fd;font-size:12px;font-weight:900;letter-spacing:.08em;text-transform:uppercase;font-family:ui-monospace,SFMono-Regular,Menlo,Monaco,Consolas,monospace}.code-output-card pre{margin:0;padding:14px 16px;color:#d4d4d4;white-space:pre-wrap;overflow-x:auto;font-family:ui-monospace,SFMono-Regular,Menlo,Monaco,Consolas,monospace;font-size:14px;line-height:1.65}.field-help{display:block;color:var(--muted);font-size:13px;font-weight:700;margin:8px 0 0}.inline-template-button{width:fit-content;margin-top:9px}.lesson-content-rich ul{margin:0 0 14px 20px;padding:0}.lesson-content-rich ul li{margin:6px 0;line-height:1.65}.post-mini-badges .helpful{color:#7c3aed}.post-admin-actions .liked-button,.tiny-button.liked{background:#fee2e2;color:#be123c}.post-admin-actions .active-action{background:#dcfce7;color:#166534}.comment.threaded{border:1px solid rgba(226,232,240,.9);background:#fff;box-shadow:0 8px 20px #0f172a09}.comment.threaded.depth-1{margin-left:26px;background:#f8fafc}.comment.threaded.depth-2{margin-left:44px;background:#f9fafb}.comment.threaded.depth-3{margin-left:58px;background:#f9fafb}.comment-head{display:flex;justify-content:space-between;gap:10px;align-items:center}.comment-head>div{display:flex;align-items:center;gap:8px;color:var(--muted)}.comment-actions-row{display:flex;flex-wrap:wrap;gap:8px;margin-top:4px}.comment-actions-row .tiny-button{display:inline-flex;align-items:center;gap:5px}.reply-form{margin:8px 0 2px}.reply-list{display:grid;gap:10px;margin-top:10px}.tiny-button.danger{color:#dc2626;background:#fee2e2}.resource-preview{word-break:break-all}.community-code-section .runnable-code-block{margin-top:8px}@media (max-width: 720px){.comment.threaded.depth-1,.comment.threaded.depth-2,.comment.threaded.depth-3{margin-left:12px}.post-admin-actions{justify-content:flex-start}}