:root{--color-bg-primary:#fff;--color-bg-secondary:#f5f5f5;--color-text-primary:#1a1a1a;--color-text-secondary:#666;--color-border:#e0e0e0;--color-accent:#007bff}[data-theme=dark],html.dark{--color-bg-primary:#1a1a1a;--color-bg-secondary:#2d2d2d;--color-text-primary:#fff;--color-text-secondary:#b0b0b0;--color-border:#404040;--color-accent:#4a9eff}*{box-sizing:border-box;margin:0;padding:0}body{background-color:var(--color-bg-primary);color:var(--color-text-primary);font-family:-apple-system,BlinkMacSystemFont,Segoe UI,Roboto,Oxygen,Ubuntu,Cantarell,sans-serif;transition:background-color .3s,color .3s}a{color:var(--color-accent);text-decoration:none}a:hover{text-decoration:underline}.container{margin:0 auto;padding:0 40px}.btn{background-color:var(--color-accent);border:none;border-radius:4px;color:#fff;cursor:pointer;display:inline-block;padding:10px 20px;transition:opacity .3s}.btn:hover{opacity:.9}.btn-secondary{color:var(--color-text-primary)}.btn-secondary,.card{background-color:var(--color-bg-secondary)}.card{border:1px solid var(--color-border);border-radius:8px;margin-bottom:20px;padding:20px}.grid{display:grid;gap:20px;grid-template-columns:repeat(auto-fill,minmax(250px,1fr))}