:root{
  --bg:#f6f9fc;--surface:#fff;--surface-2:#f0f5f9;--text:#14213d;--muted:#64748b;
  --line:#dfe8f1;--primary:#147d92;--primary-2:#0f9f87;--primary-soft:#e6f6f5;
  --danger:#b42318;--warning:#b54708;--success:#027a48;--shadow:0 12px 35px rgba(25,55,85,.08);
  --radius:18px;--radius-sm:12px;--container:1200px;
}
*{box-sizing:border-box}html{scroll-behavior:smooth}body{margin:0;background:var(--bg);color:var(--text);font-family:Inter,"PingFang SC","Microsoft YaHei",system-ui,-apple-system,sans-serif;line-height:1.65;-webkit-font-smoothing:antialiased}
a{color:var(--primary);text-decoration:none}a:hover{color:#0d6678}.container{width:min(var(--container),calc(100% - 36px));margin:auto}.page{min-height:calc(100vh - 150px);padding:34px 0 70px}
.site-header{position:sticky;top:0;z-index:50;background:rgba(255,255,255,.9);backdrop-filter:blur(18px);border-bottom:1px solid rgba(223,232,241,.9)}.header-inner{height:70px;display:flex;align-items:center;gap:24px}.brand{display:flex;align-items:center;gap:11px;color:var(--text);font-weight:800;letter-spacing:-.02em}.brand-mark{width:35px;height:35px;border-radius:12px;background:linear-gradient(135deg,var(--primary),var(--primary-2));box-shadow:0 8px 20px rgba(20,125,146,.23);position:relative}.brand-mark:after{content:"";position:absolute;inset:9px;border:2px solid #fff;border-radius:7px}.nav{display:flex;align-items:center;gap:4px;flex:1}.nav a{padding:9px 11px;color:#42526b;border-radius:10px;font-size:14px}.nav a:hover,.nav a.active{background:var(--surface-2);color:var(--text)}.header-actions{display:flex;align-items:center;gap:8px}.search-mini{display:flex;background:var(--surface-2);border:1px solid var(--line);border-radius:12px;overflow:hidden}.search-mini input{width:150px;border:0;background:transparent;padding:9px 12px;outline:none}.search-mini button{border:0;background:transparent;padding:0 10px;color:var(--muted);cursor:pointer}.mobile-menu{display:none}
.site-footer{background:#fff;border-top:1px solid var(--line);padding:28px 0;color:var(--muted);font-size:14px}.footer-inner{display:flex;justify-content:space-between;gap:20px;flex-wrap:wrap}
.btn{display:inline-flex;align-items:center;justify-content:center;gap:7px;min-height:40px;padding:9px 15px;border-radius:11px;border:1px solid transparent;font:inherit;font-weight:650;cursor:pointer;transition:.18s ease}.btn:hover{transform:translateY(-1px)}.btn-primary{background:linear-gradient(135deg,var(--primary),#0c8aa1);color:#fff;box-shadow:0 8px 20px rgba(20,125,146,.2)}.btn-primary:hover{color:#fff}.btn-secondary{background:#fff;border-color:var(--line);color:var(--text)}.btn-soft{background:var(--primary-soft);color:#126b75}.btn-danger{background:#fff1f0;color:var(--danger);border-color:#ffd5d2}.btn-sm{min-height:34px;padding:6px 11px;font-size:13px}.btn-block{width:100%}.button-row{display:flex;gap:10px;flex-wrap:wrap;align-items:center}
.card{background:var(--surface);border:1px solid rgba(223,232,241,.95);border-radius:var(--radius);box-shadow:var(--shadow)}.card-body{padding:24px}.card-header{display:flex;align-items:center;justify-content:space-between;gap:15px;padding:20px 24px;border-bottom:1px solid var(--line)}.card-title{margin:0;font-size:18px}.grid{display:grid;gap:20px}.grid-2{grid-template-columns:repeat(2,minmax(0,1fr))}.grid-3{grid-template-columns:repeat(3,minmax(0,1fr))}.grid-4{grid-template-columns:repeat(4,minmax(0,1fr))}.stack{display:flex;flex-direction:column;gap:18px}.split{display:grid;grid-template-columns:minmax(0,1fr) 320px;gap:24px}.sidebar{position:sticky;top:94px;align-self:start}.section{margin-top:38px}.section-head{display:flex;justify-content:space-between;align-items:end;gap:20px;margin-bottom:18px}.section-title{margin:0;font-size:27px;letter-spacing:-.03em}.section-subtitle{color:var(--muted);margin:5px 0 0}.eyebrow{display:inline-flex;color:var(--primary);background:var(--primary-soft);border-radius:999px;padding:5px 10px;font-size:12px;font-weight:800;letter-spacing:.05em;text-transform:uppercase}
.hero{background:radial-gradient(circle at 90% 10%,rgba(15,159,135,.16),transparent 33%),linear-gradient(135deg,#fff,#eef8fa);border:1px solid #d9ebef;border-radius:28px;padding:58px;box-shadow:var(--shadow);overflow:hidden;position:relative}.hero h1{max-width:760px;font-size:clamp(34px,5vw,64px);line-height:1.08;margin:14px 0 18px;letter-spacing:-.055em}.hero p{max-width:720px;color:#53657d;font-size:18px}.hero-actions{display:flex;gap:12px;flex-wrap:wrap;margin-top:26px}.hero-orb{position:absolute;width:250px;height:250px;border-radius:50%;right:-60px;bottom:-110px;background:linear-gradient(135deg,rgba(20,125,146,.18),rgba(15,159,135,.08))}
.module-card{padding:23px;min-height:168px;display:flex;flex-direction:column;color:var(--text);transition:.2s ease}.module-card:hover{transform:translateY(-3px);box-shadow:0 18px 40px rgba(25,55,85,.12)}.module-icon{width:44px;height:44px;border-radius:14px;background:var(--primary-soft);display:grid;place-items:center;color:var(--primary);font-weight:900;margin-bottom:17px}.module-card h3{margin:0 0 7px}.module-card p{margin:0;color:var(--muted);font-size:14px}.module-card .arrow{margin-top:auto;padding-top:14px;color:var(--primary);font-weight:700;font-size:13px}
.content-card{overflow:hidden}.cover{height:168px;background:linear-gradient(135deg,#e4f4f5,#edf3fa);display:flex;align-items:center;justify-content:center;color:var(--primary);font-size:38px}.cover img{width:100%;height:100%;object-fit:cover}.content-card .card-body{padding:19px}.content-card h3{margin:0 0 7px;font-size:18px}.content-card p{color:var(--muted);font-size:14px;margin:0}.meta{display:flex;gap:12px;flex-wrap:wrap;color:var(--muted);font-size:13px;margin-top:12px}.badge{display:inline-flex;align-items:center;border-radius:999px;padding:4px 9px;background:var(--surface-2);color:#526277;font-size:12px;font-weight:700}.badge-success{background:#ecfdf3;color:var(--success)}.badge-warning{background:#fffaeb;color:var(--warning)}.badge-danger{background:#fff1f0;color:var(--danger)}.badge-primary{background:var(--primary-soft);color:var(--primary)}
.page-head{display:flex;justify-content:space-between;align-items:flex-end;gap:20px;margin-bottom:24px}.page-head h1{margin:0;font-size:36px;letter-spacing:-.045em}.page-head p{color:var(--muted);margin:6px 0 0}.breadcrumb{display:flex;gap:7px;align-items:center;flex-wrap:wrap;color:var(--muted);font-size:14px;margin-bottom:14px}.breadcrumb span{color:#a0aec0}
.form-card{max-width:780px;margin:auto}.form-group{margin-bottom:18px}.form-group label,.form-card label{display:block;font-weight:700;margin-bottom:7px}.helptext,.help-text{display:block;color:var(--muted);font-size:13px;margin-top:5px}.form-control{width:100%;padding:11px 13px;border:1px solid #cfdbe7;border-radius:11px;background:#fff;color:var(--text);font:inherit;outline:none;transition:.15s}.form-control:focus{border-color:var(--primary);box-shadow:0 0 0 4px rgba(20,125,146,.1)}textarea.form-control{resize:vertical}.checkbox{accent-color:var(--primary)}.errorlist{list-style:none;padding:10px 12px;margin:7px 0;background:#fff1f0;color:var(--danger);border-radius:10px;font-size:14px}.field-wrap{margin-bottom:18px}.required-star{color:var(--danger)}
.messages{display:grid;gap:10px;margin:18px auto}.message{padding:13px 16px;border-radius:12px;border:1px solid}.message.success{background:#ecfdf3;border-color:#abefc6;color:#05603a}.message.error{background:#fff1f0;border-color:#fecdca;color:#912018}.message.warning{background:#fffaeb;border-color:#fedf89;color:#93370d}.message.info{background:#eff8ff;border-color:#b2ddff;color:#175cd3}
.table-wrap{overflow:auto;border-radius:var(--radius);border:1px solid var(--line);background:#fff}.table{width:100%;border-collapse:collapse;min-width:720px}.table th{background:#f8fafc;color:#58677c;text-align:left;font-size:12px;text-transform:uppercase;letter-spacing:.04em;padding:12px 15px;border-bottom:1px solid var(--line)}.table td{padding:14px 15px;border-bottom:1px solid #edf1f5;vertical-align:middle}.table tr:last-child td{border-bottom:0}.table tr:hover td{background:#fbfdff}.table-actions{display:flex;gap:7px;flex-wrap:wrap}.bulk-bar{position:sticky;bottom:16px;background:#15273d;color:#fff;padding:12px 16px;border-radius:15px;display:flex;justify-content:space-between;align-items:center;gap:15px;box-shadow:0 16px 40px rgba(15,31,50,.28);margin-top:15px}.bulk-bar select{background:#fff;color:var(--text);padding:8px;border-radius:9px}
.file-grid{display:grid;grid-template-columns:repeat(auto-fill,minmax(180px,1fr));gap:15px}.file-card{padding:18px;color:var(--text);position:relative}.file-icon{width:48px;height:48px;border-radius:14px;background:#edf6f8;display:grid;place-items:center;color:var(--primary);font-weight:900;text-transform:uppercase}.file-card h3{font-size:15px;margin:14px 0 4px;overflow-wrap:anywhere}.file-card p{font-size:12px;color:var(--muted);margin:0}.file-preview{background:#eef3f7;border-radius:14px;min-height:520px;overflow:hidden}.file-preview iframe,.file-preview img,.file-preview video{width:100%;height:70vh;border:0;object-fit:contain;background:#fff}.file-info{display:grid;grid-template-columns:130px 1fr;gap:10px;font-size:14px}.file-info dt{color:var(--muted)}.file-info dd{margin:0;overflow-wrap:anywhere}
.prose{font-size:16px;line-height:1.8;color:#28384e}.prose h1,.prose h2,.prose h3{line-height:1.25;letter-spacing:-.025em;margin-top:1.5em}.prose h2{border-bottom:1px solid var(--line);padding-bottom:8px}.prose img{max-width:100%;border-radius:12px}.prose pre{background:#14213d;color:#e6edf5;border-radius:13px;padding:17px;overflow:auto}.prose code{font-family:"SFMono-Regular",Consolas,monospace;background:#edf2f7;padding:2px 5px;border-radius:5px}.prose pre code{background:transparent;padding:0}.prose table{border-collapse:collapse;width:100%;overflow:auto}.prose th,.prose td{border:1px solid var(--line);padding:9px 11px}.prose blockquote{margin-left:0;border-left:4px solid var(--primary);padding:8px 16px;background:var(--primary-soft);border-radius:0 10px 10px 0;color:#385066}
.markdown-editor{display:grid;grid-template-columns:1fr 1fr;min-height:70vh;border:1px solid var(--line);border-radius:var(--radius);overflow:hidden;background:#fff}.markdown-pane{min-width:0}.markdown-pane:first-child{border-right:1px solid var(--line)}.markdown-pane-head{padding:11px 15px;background:#f8fafc;border-bottom:1px solid var(--line);font-weight:700;font-size:13px}.markdown-input{width:100%;height:calc(70vh - 45px);border:0;resize:none;padding:20px;outline:none;font:14px/1.7 "SFMono-Regular",Consolas,monospace}.markdown-output{height:calc(70vh - 45px);overflow:auto;padding:25px}.markdown-toolbar{display:flex;justify-content:space-between;gap:10px;flex-wrap:wrap;margin-bottom:12px}
.tutorial-layout{display:grid;grid-template-columns:245px minmax(0,1fr);gap:24px}.tutorial-nav{position:sticky;top:94px;align-self:start;max-height:calc(100vh - 120px);overflow:auto}.tutorial-nav a{display:block;padding:9px 11px;border-radius:9px;color:#45566d;font-size:14px}.tutorial-nav a:hover,.tutorial-nav a.active{background:var(--primary-soft);color:var(--primary)}
.progress{height:10px;background:#e7edf3;border-radius:999px;overflow:hidden}.progress-bar{height:100%;background:linear-gradient(90deg,var(--primary),var(--primary-2));border-radius:inherit;transition:width .4s}.countdown-value{font-size:clamp(26px,4vw,44px);font-weight:800;letter-spacing:-.04em}.stat-card{padding:20px}.stat-value{font-size:30px;font-weight:850;letter-spacing:-.04em}.stat-label{color:var(--muted);font-size:14px}.status-line{display:flex;justify-content:space-between;align-items:center;gap:10px;margin-bottom:8px}
.assignment-requirement{padding:18px;border:1px solid var(--line);border-radius:14px;background:#fbfdff}.upload-zone{border:1.5px dashed #b8ccd9;border-radius:13px;padding:18px;background:#fff}.submission-summary{background:var(--primary-soft);border:1px solid #ccebea;border-radius:14px;padding:17px}.receipt-code{font-family:monospace;background:#14213d;color:#fff;padding:14px;border-radius:12px;overflow-wrap:anywhere}
.archive-tree{list-style:none;padding:0;margin:0}.archive-tree li{margin:8px 0}.tree-row{display:flex;align-items:center;justify-content:space-between;gap:12px;padding:13px 15px;border:1px solid var(--line);border-radius:12px;background:#fff}.tree-children{margin-left:26px;border-left:2px solid #dfe8f1;padding-left:15px}.completion-panel{background:linear-gradient(135deg,#ecfbf8,#eff8ff);border:1px solid #cce9e8;border-radius:16px;padding:20px}
.admin-shell{display:grid;grid-template-columns:225px minmax(0,1fr);gap:24px}.admin-nav{position:sticky;top:94px;align-self:start;background:#fff;border:1px solid var(--line);border-radius:16px;padding:12px}.admin-nav h3{font-size:12px;color:var(--muted);text-transform:uppercase;padding:8px 10px;margin:4px 0}.admin-nav a{display:block;padding:9px 11px;border-radius:9px;color:#415269;font-size:14px}.admin-nav a:hover{background:var(--surface-2);color:var(--text)}.admin-nav .separator{height:1px;background:var(--line);margin:8px 0}.task-status{display:flex;align-items:center;gap:8px}.status-dot{width:9px;height:9px;border-radius:50%;background:#94a3b8}.status-dot.success{background:#12b76a}.status-dot.failed{background:#f04438}.status-dot.running{background:#2e90fa}.status-dot.queued{background:#f79009}
.empty{padding:50px 24px;text-align:center;color:var(--muted)}.empty-icon{width:62px;height:62px;border-radius:20px;background:var(--surface-2);margin:0 auto 15px;display:grid;place-items:center;font-size:25px}.divider{height:1px;background:var(--line);margin:20px 0}.muted{color:var(--muted)}.small{font-size:13px}.text-danger{color:var(--danger)}.text-success{color:var(--success)}.nowrap{white-space:nowrap}.sr-only{position:absolute;width:1px;height:1px;padding:0;margin:-1px;overflow:hidden;clip:rect(0,0,0,0);white-space:nowrap;border:0}
.modal{position:fixed;inset:0;background:rgba(10,25,42,.5);display:none;align-items:center;justify-content:center;padding:20px;z-index:100}.modal.open{display:flex}.modal-card{background:#fff;border-radius:18px;max-width:520px;width:100%;padding:24px;box-shadow:0 25px 70px rgba(0,0,0,.25)}
@media(max-width:1000px){.nav{display:none}.mobile-menu{display:inline-flex}.grid-4{grid-template-columns:repeat(2,1fr)}.grid-3{grid-template-columns:repeat(2,1fr)}.split{grid-template-columns:1fr}.sidebar{position:static}.admin-shell{grid-template-columns:1fr}.admin-nav{position:static;display:flex;overflow:auto}.admin-nav h3,.admin-nav .separator{display:none}.admin-nav a{white-space:nowrap}.tutorial-layout{grid-template-columns:1fr}.tutorial-nav{position:static;max-height:none}.hero{padding:40px}}
@media(max-width:680px){.container{width:min(100% - 24px,var(--container))}.page{padding-top:22px}.grid-2,.grid-3,.grid-4{grid-template-columns:1fr}.hero{padding:30px 24px;border-radius:22px}.hero h1{font-size:36px}.page-head{align-items:flex-start;flex-direction:column}.page-head h1{font-size:30px}.header-inner{height:62px}.search-mini{display:none}.markdown-editor{grid-template-columns:1fr}.markdown-pane:first-child{border-right:0;border-bottom:1px solid var(--line)}.markdown-input,.markdown-output{height:48vh}.card-body{padding:18px}.bulk-bar{align-items:flex-start;flex-direction:column}.file-info{grid-template-columns:1fr}.tutorial-layout{display:block}}
@media print{.site-header,.site-footer,.button-row,.markdown-toolbar,.admin-nav{display:none!important}.page{padding:0}.card{box-shadow:none;border:0}.container{width:100%}body{background:#fff}.prose{font-size:11pt}}
.narrow-page{max-width:940px}.upload-zone{border:1px dashed #b8d9d5;border-radius:16px;padding:22px;text-align:center;background:#f7fbfb;position:relative}.upload-zone input[type=file]{width:100%;margin-top:10px}.upload-icon{width:38px;height:38px;border-radius:12px;background:#e2f5f2;color:#15756e;display:grid;place-items:center;margin:0 auto 8px;font-size:22px}.upload-list{margin-top:10px}.sticky-actions{position:sticky;bottom:0;background:rgba(255,255,255,.94);backdrop-filter:blur(8px);padding:14px 0 2px;border-top:1px solid var(--line);z-index:3}#tutorial-content:fullscreen{background:#fff;padding:30px;overflow:auto}
.align-start{align-items:start}.compact{gap:8px}.list-row{display:flex;justify-content:space-between;gap:16px;align-items:center;padding:12px 0;border-bottom:1px solid var(--line)}.list-row:last-child{border-bottom:0}
.pagination{display:flex;justify-content:space-between;align-items:center;gap:14px;margin-top:24px;padding:14px 0}