:root{--primary-color: #2563eb;--surface-color: #ffffff;--background-color: #f8fafc;--text-color: #1e293b;--text-secondary: #64748b;--border-color: #e2e8f0}.dark-theme{--primary-color: #60a5fa;--surface-color: #1e293b;--background-color: #0f172a;--text-color: #f8fafc;--text-secondary: #cbd5e1;--border-color: #334155}*{margin:0;padding:0;box-sizing:border-box}body{font-family:-apple-system,BlinkMacSystemFont,Segoe UI,Roboto,Oxygen,Ubuntu,Cantarell,Open Sans,Helvetica Neue,sans-serif;background-color:var(--background-color);color:var(--text-color);transition:background-color .3s,color .3s}a{color:var(--primary-color)}button{cursor:pointer}.container{max-width:1200px;margin:0 auto;padding:0 1rem}.card{background:var(--surface-color);border-radius:.5rem;padding:1.5rem;box-shadow:0 1px 3px #0000001a}.btn{padding:.5rem 1rem;border-radius:.375rem;border:none;background:var(--primary-color);color:#fff;font-weight:500;transition:opacity .2s}.btn:hover{opacity:.9}