:root{--color-primary: #4f46e5;--color-primary-light: #818cf8;--color-primary-dark: #3730a3;--color-success: #10b981;--color-warning: #f59e0b;--color-danger: #ef4444;--color-bg: #f8fafc;--color-surface: #ffffff;--color-text: #1e293b;--color-text-muted: #64748b;--color-border: #e2e8f0;--sidebar-width: 240px;--header-height: 60px;--radius: 8px;--shadow: 0 1px 3px rgba(0, 0, 0, .08), 0 1px 2px rgba(0, 0, 0, .06);--shadow-md: 0 4px 6px rgba(0, 0, 0, .07), 0 2px 4px rgba(0, 0, 0, .06)}*,*:before,*:after{box-sizing:border-box;margin:0;padding:0}body{font-family:-apple-system,BlinkMacSystemFont,Segoe 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solid var(--color-border);border-radius:8px;cursor:pointer;font-size:.9rem;transition:all .15s}.role-option input{display:none}.role-option.selected{border-color:var(--color-primary);background:#2563eb0d;color:var(--color-primary);font-weight:500}.landing{min-height:100vh}.landing-header{display:flex;align-items:center;justify-content:space-between;padding:16px 32px}.landing-hero{text-align:center;padding:80px 24px 60px}.landing-hero h1{font-size:2.5rem;font-weight:800;margin-bottom:12px}.landing-hero p{font-size:1.15rem;color:var(--color-text-muted);margin-bottom:32px}.landing-features{display:grid;grid-template-columns:repeat(auto-fit,minmax(260px,1fr));gap:24px;max-width:960px;margin:0 auto;padding:0 24px 80px}.feature-card{text-align:center;padding:32px 24px;background:var(--color-surface);border-radius:12px;box-shadow:var(--shadow)}.feature-card h3{margin:12px 0 8px;font-size:1.1rem}.feature-card 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var(--color-border);border-radius:var(--radius)}.exec-title{font-size:.9rem;font-weight:600;margin-bottom:10px;display:flex;align-items:center;gap:6px}.exec-hint{font-size:.85rem;color:var(--color-text-muted)}.exec-result{margin-top:12px}.exec-error{margin-top:8px;padding:8px 12px;background:#fef2f2;color:var(--color-danger);border-radius:var(--radius);font-size:.85rem;display:flex;align-items:center;gap:6px}.exec-timeout{padding:8px 12px;background:#fffbeb;color:#d97706;border-radius:var(--radius);font-size:.85rem;display:flex;align-items:center;gap:6px;margin-bottom:8px}.exec-section{margin-bottom:8px}.exec-label{font-size:.78rem;font-weight:500;color:var(--color-text-muted);display:block;margin-bottom:2px}.exec-output{background:#1e293b;color:#e2e8f0;padding:10px 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h1{font-size:1.8rem;font-weight:700;margin:8px 0 4px}.showcase-hero p{color:var(--color-text-muted);font-size:.95rem}.showcase-tabs{display:flex;justify-content:center;gap:4px;margin-bottom:24px}.showcase-tab{padding:6px 18px;border:1px solid var(--color-border);border-radius:var(--radius);background:var(--color-surface);font-size:.85rem;cursor:pointer;transition:all .15s}.showcase-tab:hover{border-color:var(--color-primary);color:var(--color-primary)}.showcase-tab.active{background:var(--color-primary);color:#fff;border-color:var(--color-primary)}.showcase-grid{display:grid;grid-template-columns:repeat(auto-fill,minmax(260px,1fr));gap:20px}.showcase-card{display:block;background:var(--color-surface);border:1px solid var(--color-border);border-radius:var(--radius);overflow:hidden;text-decoration:none;color:var(--color-text);transition:box-shadow .15s,transform 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auto;padding:24px}.showcase-back-link{display:inline-flex;align-items:center;gap:6px;color:var(--color-text-muted);font-size:.85rem;margin-bottom:20px}.showcase-back-link:hover{color:var(--color-primary);text-decoration:none}.showcase-home-link{display:inline-flex;align-items:center;gap:6px;color:var(--color-text-muted);font-size:.85rem;margin-bottom:20px;margin-left:16px}.showcase-home-link:hover{color:var(--color-primary);text-decoration:none}.showcase-topbar{margin-bottom:16px}.showcase-detail-layout{display:grid;grid-template-columns:1fr 380px;gap:24px;align-items:start}.showcase-player-wrapper{border:1px solid var(--color-border);border-radius:var(--radius);overflow:hidden;background:#fff}.showcase-no-file{padding:80px 20px;text-align:center;color:var(--color-text-muted);background:var(--color-bg)}.showcase-detail-info{background:var(--color-surface);border:1px solid var(--color-border);border-radius:var(--radius);overflow:hidden}.showcase-detail-cover{height:200px}.showcase-detail-title{font-size:1.3rem;font-weight:700;padding:16px 20px 0}.showcase-detail-meta{display:flex;flex-wrap:wrap;gap:12px;padding:8px 20px 16px;font-size:.82rem;color:var(--color-text-muted);border-bottom:1px solid var(--color-border)}.showcase-detail-meta span{display:flex;align-items:center;gap:4px}.showcase-detail-section{padding:16px 20px;border-bottom:1px solid var(--color-border)}.showcase-detail-section:last-child{border-bottom:none}.showcase-detail-section h3{font-size:.9rem;font-weight:600;margin-bottom:6px}.showcase-detail-desc{font-size:.85rem;color:var(--color-text-muted);line-height:1.5}.showcase-instructions{font-size:.82rem;color:var(--color-text);line-height:1.6;white-space:pre-wrap;font-family:inherit;background:var(--color-bg);padding:10px 14px;border-radius:4px}.project-scratch-layout{display:grid;grid-template-columns:1fr 340px;gap:24px;align-items:start;margin-top:8px}.project-scratch-info{background:var(--color-surface);border:1px solid var(--color-border);border-radius:var(--radius);overflow:hidden}.project-cover{height:180px}.project-stats{display:flex;flex-wrap:wrap;gap:12px;padding:12px 16px;font-size:.82rem;color:var(--color-text-muted);border-bottom:1px solid var(--color-border)}.project-stats span{display:flex;align-items:center;gap:4px}.project-instructions{padding:14px 16px}.project-instructions h4{font-size:.85rem;font-weight:600;margin-bottom:6px}.project-instructions pre{font-size:.8rem;line-height:1.5;white-space:pre-wrap;font-family:inherit;color:var(--color-text);background:var(--color-bg);padding:10px 12px;border-radius:4px}.admin-stats-bar{display:flex;gap:16px;margin-bottom:24px}.stat-card{display:flex;align-items:center;gap:8px;padding:14px 20px;background:var(--color-surface);border:1px solid var(--color-border);border-radius:var(--radius);font-weight:500}.admin-table{width:100%;border-collapse:collapse;background:var(--color-surface);border:1px solid var(--color-border);border-radius:var(--radius);overflow:hidden}.admin-table th,.admin-table td{padding:12px 16px;text-align:left;font-size:.875rem}.admin-table th{background:var(--color-bg);font-weight:600;border-bottom:2px solid var(--color-border)}.admin-table td{border-bottom:1px solid var(--color-border)}.admin-table tr:last-child td{border-bottom:none}.admin-table tr:hover td{background:var(--color-bg)}.student-name{font-weight:600}@media (max-width: 768px){.sidebar{display:none}.main-content{padding:16px}.header-nav{margin-left:16px}.project-grid{grid-template-columns:1fr}.landing-hero h1{font-size:1.8rem}.showcase-detail-layout,.project-scratch-layout{grid-template-columns:1fr}.showcase-grid{grid-template-columns:repeat(auto-fill,minmax(200px,1fr))}}