:root,:root[data-theme=dark]{--bg-primary:#0a0e14;--bg-secondary:#121820;--accent-blue:#0070f3;--accent-green:#00d26a;--text-primary:#fff;--text-secondary:#a0a0a0;--border-color:#2e3440;--font-family:"Inter", -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Oxygen, Ubuntu, Cantarell, "Open Sans", "Helvetica Neue", sans-serif}:root[data-theme=light]{--bg-primary:#fff;--bg-secondary:#f5f5f5;--accent-blue:#0056b3;--accent-green:#00a04c;--text-primary:#121820;--text-secondary:#505050;--border-color:#e0e0e0}*{box-sizing:border-box;margin:0;padding:0}body{background-color:var(--bg-primary);color:var(--text-primary);font-family:var(--font-family);-webkit-font-smoothing:antialiased;-moz-osx-font-smoothing:grayscale;line-height:1.6}a{color:inherit;text-decoration:none}ul{list-style:none}button{cursor:pointer;border:none;font-family:inherit}.container{max-width:1200px;margin:0 auto;padding:0 2rem}section{padding:6rem 0}.checkout-container{background-color:var(--bg-secondary,#1a1a1a);border:1px solid var(--border-color,#333);max-width:600px;color:var(--text-primary,#fff);border-radius:12px;margin:4rem auto;padding:2rem;box-shadow:0 8px 32px #0006}.checkout-stepper{border-bottom:2px solid var(--border-color,#333);justify-content:space-between;margin-bottom:2rem;padding-bottom:1rem;display:flex}.stepper-item{text-align:center;color:var(--text-muted,#888);flex:1;font-size:.9rem;font-weight:600;transition:color .3s}.stepper-item.active{color:var(--primary-accent,#0fc)}.checkout-step h2{color:var(--primary-accent,#0fc);margin-bottom:.5rem;font-size:1.5rem}.checkout-step p{color:var(--text-secondary,#b3b3b3);margin-bottom:1.5rem}.form-group{margin-bottom:1.5rem}.form-group label{color:var(--text-primary,#fff);margin-bottom:.5rem;font-weight:500;display:block}.nexus-input{background-color:var(--bg-primary,#0f0f0f);border:1px solid var(--border-color,#333);width:100%;color:var(--text-primary,#fff);border-radius:6px;padding:.8rem 1rem;font-size:1rem;transition:border-color .3s,box-shadow .3s}.nexus-input:focus{border-color:var(--primary-accent,#0fc);outline:none;box-shadow:0 0 0 2px #0fc3}.nexus-btn-primary{color:#000;cursor:pointer;background:linear-gradient(135deg,#0fc,#00b399);border:none;border-radius:6px;width:100%;padding:.8rem;font-size:1rem;font-weight:700;transition:transform .2s,box-shadow .2s}.nexus-btn-primary:active{transform:scale(.98)}.nexus-btn-primary:disabled{color:#666;cursor:not-allowed;background:#333}.nexus-btn-secondary{width:100%;color:var(--primary-accent,#0fc);border:1px solid var(--primary-accent,#0fc);cursor:pointer;background:0 0;border-radius:6px;padding:.8rem;font-weight:600;transition:background-color .3s}.nexus-btn-secondary:hover{background-color:#00ffcc1a}.form-actions{gap:1rem;margin-top:2rem;display:flex}.error-message{color:#ff4d4d;background-color:#ff4d4d1a;border-left:3px solid #ff4d4d;border-radius:6px;margin:1rem 0;padding:.8rem;font-size:.9rem}.spinner{text-align:center;color:var(--primary-accent,#0fc);padding:2rem}