:root {
    --bg-primary: #f5f6fa;
    --bg-card: #ffffff;
    --bg-input: #f0f1f5;
    --text-primary: #1a1a2e;
    --text-secondary: #6b7280;
    --green: #16a34a;
    --red: #dc2626;
    --blue: #2563eb;
    --border: #e5e7eb;
}

* { box-sizing: border-box; margin: 0; padding: 0; }

body {
    font-family: 'Segoe UI', system-ui, -apple-system, sans-serif;
    background: var(--bg-primary);
    color: var(--text-primary);
    min-height: 100vh;
}

a { color: var(--blue); text-decoration: none; }
a:hover { text-decoration: underline; }

/* Nav */
nav {
    background: var(--bg-card);
    border-bottom: 1px solid var(--border);
    padding: 0.75rem 2rem;
    display: flex;
    align-items: center;
    gap: 2rem;
    box-shadow: 0 1px 3px rgba(0,0,0,0.06);
}
nav .brand {
    font-size: 1.1rem;
    font-weight: 700;
    color: var(--green);
    letter-spacing: 0.5px;
}
nav .nav-links { display: flex; gap: 1.5rem; }
nav .nav-links a {
    color: var(--text-secondary);
    font-size: 0.9rem;
    padding: 0.25rem 0;
    border-bottom: 2px solid transparent;
    transition: all 0.2s;
}
nav .nav-links a:hover, nav .nav-links a.active {
    color: var(--text-primary);
    border-bottom-color: var(--green);
    text-decoration: none;
}

/* Layout */
.container { max-width: 1200px; margin: 0 auto; padding: 1.5rem 2rem; }

/* Cards */
.card-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
    gap: 1rem;
    margin-bottom: 1.5rem;
}
.card {
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: 8px;
    padding: 1.25rem;
    box-shadow: 0 1px 3px rgba(0,0,0,0.04);
}
.card .label {
    font-size: 0.75rem;
    text-transform: uppercase;
    color: var(--text-secondary);
    letter-spacing: 1px;
    margin-bottom: 0.5rem;
}
.card .value {
    font-size: 1.8rem;
    font-weight: 700;
    font-variant-numeric: tabular-nums;
}
.card .value.red { color: var(--red); }
.card .value.green { color: var(--green); }

/* Sections */
.section {
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: 8px;
    padding: 1.25rem;
    margin-bottom: 1.5rem;
    box-shadow: 0 1px 3px rgba(0,0,0,0.04);
}
.section h2 {
    font-size: 1rem;
    margin-bottom: 1rem;
    color: var(--text-secondary);
    font-weight: 600;
}

/* Chart container */
.chart-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 1rem;
}
.chart-header input[type="date"] {
    background: var(--bg-input);
    color: var(--text-primary);
    border: 1px solid var(--border);
    border-radius: 4px;
    padding: 0.35rem 0.5rem;
    font-size: 0.85rem;
}

/* Tables */
table {
    width: 100%;
    border-collapse: collapse;
    font-size: 0.85rem;
}
th {
    text-align: left;
    color: var(--text-secondary);
    font-weight: 600;
    font-size: 0.75rem;
    text-transform: uppercase;
    letter-spacing: 0.5px;
    padding: 0.5rem 0.75rem;
    border-bottom: 2px solid var(--border);
}
td {
    padding: 0.5rem 0.75rem;
    border-bottom: 1px solid var(--border);
}
tr:last-child td { border-bottom: none; }

/* Buttons */
.btn {
    display: inline-block;
    padding: 0.4rem 1rem;
    border: none;
    border-radius: 4px;
    font-size: 0.85rem;
    cursor: pointer;
    transition: opacity 0.2s;
}
.btn:hover { opacity: 0.85; }
.btn-red { background: var(--red); color: #fff; }
.btn-green { background: var(--green); color: #fff; font-weight: 600; }
.btn-blue { background: var(--blue); color: #fff; font-weight: 600; }

/* Forms */
.form-group {
    margin-bottom: 1rem;
}
.form-group label {
    display: block;
    font-size: 0.8rem;
    color: var(--text-secondary);
    margin-bottom: 0.3rem;
    text-transform: uppercase;
    letter-spacing: 0.5px;
}
.form-group input {
    width: 100%;
    padding: 0.5rem 0.75rem;
    background: var(--bg-input);
    color: var(--text-primary);
    border: 1px solid var(--border);
    border-radius: 4px;
    font-size: 0.9rem;
}
.form-group input:focus {
    outline: none;
    border-color: var(--blue);
    box-shadow: 0 0 0 2px rgba(37,99,235,0.15);
}

/* Status badge */
.badge {
    display: inline-block;
    padding: 0.15rem 0.5rem;
    border-radius: 3px;
    font-size: 0.75rem;
    font-weight: 600;
}
.badge-green { background: rgba(22,163,74,0.1); color: var(--green); }
.badge-red { background: rgba(220,38,38,0.1); color: var(--red); }
.badge-yellow { background: rgba(202,138,4,0.1); color: #b45309; }

/* Utility */
.text-red { color: var(--red); }
.text-green { color: var(--green); }
.text-muted { color: var(--text-secondary); font-size: 0.8rem; }
.mt-1 { margin-top: 1rem; }
.mb-1 { margin-bottom: 1rem; }

/* Table row hover */
tbody tr:hover { background: rgba(0,0,0,0.02); }

/* Responsive: stack cards on small screens */
@media (max-width: 768px) {
    .container { padding: 1rem; }
    .card-grid { grid-template-columns: 1fr 1fr; }
    .chart-header { flex-direction: column; gap: 0.5rem; align-items: flex-start; }
    table { font-size: 0.75rem; }
    td, th { padding: 0.35rem 0.5rem; }
    nav { padding: 0.75rem 1rem; }
}
@media (max-width: 480px) {
    .card-grid { grid-template-columns: 1fr; }
}

/* Connection status indicator */
.conn-status {
    display: inline-block;
    width: 8px;
    height: 8px;
    border-radius: 50%;
    margin-right: 0.4rem;
    vertical-align: middle;
}
.conn-status.online { background: var(--green); box-shadow: 0 0 4px var(--green); }
.conn-status.offline { background: var(--red); box-shadow: 0 0 4px var(--red); }

/* Scrollable table wrapper */
.table-scroll { overflow-x: auto; }

/* Log viewer */
.log-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 0.75rem;
    flex-wrap: wrap;
    gap: 0.5rem;
}
.log-tabs {
    display: flex;
    gap: 0.25rem;
    flex-wrap: wrap;
}
.log-tab {
    padding: 0.3rem 0.7rem;
    border: 1px solid var(--border);
    border-radius: 4px;
    background: var(--bg-input);
    color: var(--text-secondary);
    font-size: 0.8rem;
    cursor: pointer;
    transition: all 0.2s;
}
.log-tab:hover { border-color: var(--blue); color: var(--text-primary); }
.log-tab.active {
    background: var(--blue);
    color: #fff;
    border-color: var(--blue);
}
.log-controls {
    display: flex;
    align-items: center;
    gap: 1rem;
    margin-bottom: 0.5rem;
}
.log-viewer {
    background: #1a1a2e;
    color: #e0e0e0;
    font-family: 'Courier New', monospace;
    font-size: 0.75rem;
    line-height: 1.5;
    padding: 1rem;
    border-radius: 6px;
    max-height: 500px;
    overflow: auto;
    white-space: pre-wrap;
    word-wrap: break-word;
}