:root{--color-primary:#06c;--color-primary-dark:#004c99;--color-secondary:#f60;--color-success:#28a745;--color-warning:#ffc107;--color-danger:#dc3545;--color-safety-yellow:#fc0;--color-safety-orange:#f60;--color-safety-green:#0c6;--color-bg:#fff;--color-bg-secondary:#f8f9fa;--color-text:#1a1a2e;--color-text-muted:#4a5568;--color-border:#e2e8f0;--space-xs:0.25rem;--space-sm:0.5rem;--space-md:1rem;--space-lg:1.5rem;--space-xl:2rem;--space-2xl:3rem;--font-sans:system-ui,-apple-system,BlinkMacSystemFont,"Segoe UI",Roboto,sans-serif;--font-mono:"SF Mono",Monaco,"Cascadia Code",monospace;--radius-sm:4px;--radius-md:8px;--radius-lg:12px;--radius-full:9999px;--shadow-sm:0 1px 2px rgba(0,0,0,.05);--shadow-md:0 4px 6px rgba(0,0,0,.1);--shadow-lg:0 10px 25px rgba(0,0,0,.15)}[data-theme=dark]{--color-primary:#3b82f6;--color-primary-dark:#60a5fa;--color-bg:#0f111a;--color-bg-secondary:#1e2130;--color-text:#f8fafc;--color-text-muted:#cbd5e1;--color-border:#2d3748;--shadow-sm:0 1px 2px rgba(0,0,0,.3);--shadow-md:0 4px 6px rgba(0,0,0,.5);--shadow-lg:0 10px 25px rgba(0,0,0,.6)}*{margin:0;padding:0;box-sizing:border-box}body,html{font-family:var(--font-sans);background-color:var(--color-bg);color:var(--color-text);line-height:1.6}a{color:var(--color-primary);text-decoration:none}a:hover{text-decoration:underline}.container{max-width:1200px;margin:0 auto;padding:0 var(--space-md)}.card{background:var(--color-bg);border:1px solid var(--color-border);border-radius:var(--radius-lg);padding:var(--space-lg);box-shadow:var(--shadow-sm);transition:box-shadow .2s,transform .2s}.card:hover{box-shadow:var(--shadow-md);transform:translateY(-2px)}.btn{display:inline-flex;align-items:center;justify-content:center;padding:var(--space-sm) var(--space-lg);border-radius:var(--radius-md);font-weight:600;cursor:pointer;border:none;transition:all .2s}.btn-primary{background:var(--color-primary);color:#fff}.btn-primary:hover{background:var(--color-primary-dark)}.btn-secondary{background:var(--color-secondary);color:#fff}.lesson{max-width:800px;margin:0 auto;padding:var(--space-xl)}.lesson h1{font-size:2rem;margin-bottom:var(--space-lg);color:var(--color-primary)}.lesson h2{font-size:1.5rem;margin:var(--space-xl) 0 var(--space-md);color:var(--color-text)}.lesson section{margin-bottom:var(--space-xl)}.lesson ul{padding-left:var(--space-lg)}.lesson li{margin-bottom:var(--space-sm)}.video{position:relative;padding-bottom:56.25%;height:0;overflow:hidden;border-radius:var(--radius-lg);background:var(--color-bg-secondary)}.video iframe{position:absolute;top:0;left:0;width:100%;height:100%;border:none}.callout{padding:var(--space-md);border-radius:var(--radius-md);margin:var(--space-md) 0}.callout-warning{background:rgba(255,193,7,.15);border-left:4px solid var(--color-warning)}.callout-danger{background:rgba(220,53,69,.15);border-left:4px solid var(--color-danger)}.callout-success{background:rgba(40,167,69,.15);border-left:4px solid var(--color-success)}.badge{display:inline-block;padding:var(--space-xs) var(--space-sm);border-radius:var(--radius-full);font-size:.75rem;font-weight:600;text-transform:uppercase}.badge-lifting{background:var(--color-safety-orange);color:#fff}.badge-hse{background:var(--color-safety-green);color:#fff}.grid{display:grid;grid-gap:var(--space-lg);gap:var(--space-lg)}.grid-2{grid-template-columns:repeat(auto-fit,minmax(300px,1fr))}.grid-3{grid-template-columns:repeat(auto-fit,minmax(280px,1fr))}