:root {
  --primary: #2563eb;
  --primary-dark: #1d4ed8;
  --success: #16a34a;
  --danger: #dc2626;
  --warning: #f59e0b;
  --bg: #f8fafc;
  --card: #ffffff;
  --text: #1e293b;
  --text-muted: #64748b;
  --border: #e2e8f0;
  --radius: 12px;
}

* { margin: 0; padding: 0; box-sizing: border-box; }
body { font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif; background: var(--bg); color: var(--text); line-height: 1.6; }

.container { max-width: 960px; margin: 0 auto; padding: 0 20px; }
.header { background: var(--primary); color: #fff; padding: 16px 0; box-shadow: 0 2px 8px rgba(0,0,0,.15); }
.header .container { display: flex; justify-content: space-between; align-items: center; }
.header h1 { font-size: 1.4rem; font-weight: 700; }
.header nav { display: flex; gap: 16px; }
.header nav a { color: rgba(255,255,255,.85); text-decoration: none; font-size: .9rem; }
.header nav a:hover { color: #fff; }

.hero { text-align: center; padding: 60px 20px; background: linear-gradient(135deg, #2563eb 0%, #7c3aed 100%); color: #fff; }
.hero h2 { font-size: 2.2rem; margin-bottom: 12px; }
.hero p { font-size: 1.1rem; opacity: .9; max-width: 600px; margin: 0 auto 24px; }

.card { background: var(--card); border-radius: var(--radius); box-shadow: 0 1px 3px rgba(0,0,0,.08); padding: 24px; margin-bottom: 20px; }
.card h3 { font-size: 1.1rem; margin-bottom: 12px; color: var(--text); }

.btn { display: inline-flex; align-items: center; gap: 8px; padding: 10px 20px; border: none; border-radius: 8px; font-size: .95rem; font-weight: 600; cursor: pointer; text-decoration: none; transition: all .15s; }
.btn-primary { background: var(--primary); color: #fff; }
.btn-primary:hover { background: var(--primary-dark); }
.btn-success { background: var(--success); color: #fff; }
.btn-danger { background: var(--danger); color: #fff; }
.btn-outline { background: transparent; border: 2px solid var(--primary); color: var(--primary); }
.btn-outline:hover { background: var(--primary); color: #fff; }
.btn-sm { padding: 6px 14px; font-size: .85rem; }
.btn-lg { padding: 14px 28px; font-size: 1.1rem; }
.btn:disabled { opacity: .5; cursor: not-allowed; }

.download-box { display: inline-flex; align-items: center; gap: 12px; background: rgba(255,255,255,.15); border: 2px solid rgba(255,255,255,.3); border-radius: var(--radius); padding: 16px 24px; margin-top: 8px; }
.download-box .icon { font-size: 2rem; }

input, select { padding: 10px 14px; border: 2px solid var(--border); border-radius: 8px; font-size: .95rem; width: 100%; transition: border-color .15s; }
input:focus, select:focus { outline: none; border-color: var(--primary); }

.form-group { margin-bottom: 16px; }
.form-group label { display: block; font-weight: 600; margin-bottom: 6px; font-size: .9rem; }

.search-box { display: flex; gap: 12px; max-width: 500px; margin: 30px auto; }
.search-box input { flex: 1; font-size: 1.2rem; text-align: center; letter-spacing: 4px; }

.grid-2 { display: grid; grid-template-columns: 1fr 1fr; gap: 16px; }
.grid-3 { display: grid; grid-template-columns: 1fr 1fr 1fr; gap: 16px; }
@media (max-width: 640px) { .grid-2, .grid-3 { grid-template-columns: 1fr; } }

.stat-card { text-align: center; padding: 20px; }
.stat-card .value { font-size: 2rem; font-weight: 700; color: var(--primary); }
.stat-card .label { font-size: .85rem; color: var(--text-muted); margin-top: 4px; }

.badge { display: inline-block; padding: 3px 10px; border-radius: 20px; font-size: .78rem; font-weight: 600; }
.badge-success { background: #dcfce7; color: #166534; }
.badge-warning { background: #fef3c7; color: #92400e; }
.badge-danger { background: #fee2e2; color: #991b1b; }
.badge-info { background: #dbeafe; color: #1e40af; }

table { width: 100%; border-collapse: collapse; font-size: .9rem; }
th, td { padding: 10px 12px; text-align: left; border-bottom: 1px solid var(--border); }
th { font-weight: 600; color: var(--text-muted); font-size: .8rem; text-transform: uppercase; }
tr:hover td { background: #f1f5f9; }

.section { padding: 40px 0; }
.section h2 { font-size: 1.5rem; margin-bottom: 20px; text-align: center; }

.instructions { max-width: 700px; margin: 0 auto; }
.instructions ol { padding-left: 24px; }
.instructions li { margin-bottom: 12px; }
.instructions code { background: #f1f5f9; padding: 2px 8px; border-radius: 4px; font-size: .9rem; }

.chart-container { position: relative; height: 300px; }

.measurement-id { font-size: 2.5rem; font-weight: 700; letter-spacing: 6px; color: var(--primary); text-align: center; padding: 20px; }

.ping-row { display: flex; justify-content: space-between; align-items: center; padding: 8px 0; border-bottom: 1px solid var(--border); }
.ping-row:last-child { border: none; }
.ping-row .host { font-weight: 600; }
.ping-row .values { display: flex; gap: 16px; font-size: .9rem; }

.traceroute { font-family: 'Courier New', monospace; font-size: .85rem; background: #1e293b; color: #e2e8f0; padding: 16px; border-radius: 8px; white-space: pre-wrap; max-height: 400px; overflow-y: auto; }

.login-form { max-width: 360px; margin: 60px auto; }

.hidden { display: none !important; }

.alert { padding: 12px 16px; border-radius: 8px; margin-bottom: 16px; font-size: .9rem; }
.alert-error { background: #fee2e2; color: #991b1b; }
.alert-success { background: #dcfce7; color: #166534; }

.meta-info { display: grid; grid-template-columns: auto 1fr; gap: 4px 16px; font-size: .9rem; }
.meta-info dt { font-weight: 600; color: var(--text-muted); }
.meta-info dd { color: var(--text); }

.footer { text-align: center; padding: 24px; color: var(--text-muted); font-size: .85rem; }