:root {
  --primary: #06B6D4; --primary-hover: #0891B2; --secondary: #22D3EE;
  --accent: #F59E0B; --success: #10B981; --error: #EF4444;
  --bg: #0A1A28; --bg-elevated: #0E2334; --bg-card: #132E42;
  --bg-input: #0B1E2E; --text: #E0F0FA; --text-muted: #80B0D0; --text-dim: #446880;
  --border: #1E3852; --border-hover: #2D5472; --radius: 12px; --radius-sm: 8px;
  --font: 'Inter', system-ui, sans-serif; --mono: monospace; --transition: 200ms ease;
}
*,*::before,*::after{box-sizing:border-box;margin:0;padding:0}
body{font-family:var(--font);background:var(--bg);color:var(--text);min-height:100vh}
.app{display:flex;flex-direction:column;min-height:100vh}

.header{display:flex;align-items:center;justify-content:space-between;padding:12px 20px;background:var(--bg-elevated);border-bottom:1px solid var(--border);gap:12px;flex-shrink:0}
.header-left{display:flex;align-items:center;gap:12px}
.logo{font-size:1.3rem}
.header-title{font-size:1.05rem;font-weight:700;background:linear-gradient(135deg,var(--primary),var(--secondary));-webkit-background-clip:text;-webkit-text-fill-color:transparent;background-clip:text}
.header-right{display:flex;gap:8px;align-items:center}

.btn{display:inline-flex;align-items:center;gap:6px;padding:8px 14px;font-size:.8rem;font-weight:500;font-family:var(--font);border:none;border-radius:var(--radius-sm);cursor:pointer;transition:all var(--transition);white-space:nowrap}
.btn:disabled{opacity:.4;cursor:not-allowed}
.btn-primary{background:linear-gradient(135deg,var(--primary),var(--primary-hover));color:#fff;box-shadow:0 2px 8px rgba(6,182,212,.3)}
.btn-primary:hover{transform:translateY(-1px);box-shadow:0 4px 16px rgba(6,182,212,.4)}
.btn-ghost{background:transparent;color:var(--text-muted);border:1px solid var(--border)}
.btn-ghost:hover:not(:disabled){background:var(--bg-card);color:var(--text);border-color:var(--border-hover)}
.btn-sm{padding:5px 10px;font-size:.72rem}

.main{flex:1;overflow-y:auto;padding:20px}
.panel{max-width:800px;margin:0 auto;display:flex;flex-direction:column;gap:14px}
.panel-title{font-size:.85rem;font-weight:600}
.section-label{font-size:.72rem;font-weight:600;color:var(--text-dim);text-transform:uppercase;letter-spacing:.5px}

.form-group{display:flex;flex-direction:column;gap:4px}
.form-group label{font-size:.72rem;font-weight:500;color:var(--text-muted)}
.input{width:100%;padding:10px 14px;font-size:.9rem;font-family:var(--mono);background:var(--bg-input);border:1px solid var(--border);border-radius:var(--radius-sm);color:var(--text);outline:none}
.input:focus{border-color:var(--primary)}

.result-grid{display:grid;grid-template-columns:1fr 1fr;gap:8px}
.result-card{padding:12px 16px;background:var(--bg-card);border:1px solid var(--border);border-radius:var(--radius-sm)}
.result-label{font-size:.68rem;color:var(--text-dim);text-transform:uppercase;letter-spacing:.3px;margin-bottom:2px}
.result-value{font-size:.85rem;font-weight:600;font-family:var(--mono);color:var(--secondary)}

.map-visual{display:flex;flex-wrap:wrap;gap:3px}
.map-cell{width:12px;height:12px;border-radius:2px;transition:all var(--transition)}
.map-cell.network{background:var(--primary)}
.map-cell.host{background:rgba(6,182,212,.2);border:1px solid rgba(6,182,212,.3)}
.map-cell.broadcast{background:var(--accent)}

.subnets-table{width:100%;border-collapse:collapse;font-size:.75rem}
.subnets-table th{padding:8px 12px;text-align:left;font-weight:600;color:var(--text-dim);border-bottom:1px solid var(--border);text-transform:uppercase;font-size:.65rem;letter-spacing:.3px}
.subnets-table td{padding:8px 12px;border-bottom:1px solid rgba(30,56,82,.3);font-family:var(--mono);color:var(--text-muted)}
.subnets-table tr:hover td{background:rgba(6,182,212,.04)}

.toast{position:fixed;bottom:24px;left:50%;transform:translateX(-50%);padding:10px 20px;background:var(--bg-card);border:1px solid var(--primary);border-radius:var(--radius-sm);color:var(--primary);font-size:.8rem;font-weight:500;z-index:200;animation:toast-in .3s ease}
@keyframes toast-in{from{opacity:0;transform:translateX(-50%) translateY(10px)}to{opacity:1;transform:translateX(-50%) translateY(0)}}
::-webkit-scrollbar{width:6px}::-webkit-scrollbar-track{background:transparent}::-webkit-scrollbar-thumb{background:var(--border);border-radius:3px}
@media(max-width:768px){.result-grid{grid-template-columns:1fr}.header{flex-wrap:wrap}}