:root {
    --bg-color: #ffffff;
    --surface-color: #f8f9fa;
    --text-primary: #000000;
    --text-secondary: #495057;
    --primary-color: #000000;
    --secondary-color: #e9ecef;
    --accent-color: #0d6efd;
    --danger-color: #dc3545;
    --border-color: #dee2e6;
    --radius: 0px; /* Strict 2D, no rounding */
}

* {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
}

body {
    background-color: var(--bg-color);
    color: var(--text-primary);
    line-height: 1.5;
    -webkit-font-smoothing: antialiased;
}

/* Loader */
.loader-overlay {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: rgba(255, 255, 255, 0.95);
    z-index: 9999;
    display: flex;
    justify-content: center;
    align-items: center;
}

.loader-overlay.hidden {
    display: none;
}

.loader-spinner {
    width: 40px;
    height: 40px;
    border: 4px solid var(--border-color);
    border-top: 4px solid var(--primary-color);
    animation: spin 0.8s linear infinite;
}

@keyframes spin {
    0% { transform: rotate(0deg); }
    100% { transform: rotate(360deg); }
}

/* Topbar */
.topbar {
    background-color: var(--primary-color);
    color: #fff;
    padding: 1rem;
    display: flex;
    justify-content: space-between;
    align-items: center;
    border-bottom: 2px solid var(--primary-color);
}

.brand {
    font-weight: 700;
    font-size: 1.25rem;
    letter-spacing: -0.05em;
    text-transform: uppercase;
}

/* Layout */
.container {
    padding: 1rem;
    width: 100%;
}

@media (min-width: 768px) {
    .container {
        max-width: 700px; /* Kept narrow for mobile-first feel even on desktop */
        margin: 0 auto;
        padding: 2rem;
    }
}

/* Views */
.view { display: none; }
.view.active { display: block; }

/* Cards (Strict Flat 2D) */
h1, h2, h3, h4 {
    margin-bottom: 1rem;
    font-weight: 600;
    letter-spacing: -0.02em;
}

.card, .login-card, .metric-card {
    background: var(--surface-color);
    border: 1px solid var(--border-color);
    padding: 1.25rem;
    margin-bottom: 1rem;
}

.login-card {
    text-align: center;
    margin-top: 2rem;
}

/* Metrics Grid */
.metrics-grid {
    display: grid;
    grid-template-columns: 1fr;
    gap: 1rem;
    margin-bottom: 1rem;
}

@media (min-width: 480px) {
    .metrics-grid { grid-template-columns: 1fr 1fr; }
}

.metric-value {
    font-size: 1.75rem;
    font-weight: 700;
    margin-top: 0.5rem;
}

.metric-card.highlight {
    background-color: var(--primary-color);
    color: #fff;
    border-color: var(--primary-color);
}

/* Forms */
.form-group {
    margin-bottom: 1rem;
}

label {
    display: block;
    margin-bottom: 0.25rem;
    font-size: 0.85rem;
    font-weight: 600;
    color: var(--text-secondary);
    text-transform: uppercase;
}

input, select {
    width: 100%;
    padding: 0.75rem;
    border: 1px solid var(--border-color);
    background-color: #fff;
    font-size: 1rem;
    border-radius: 0;
    outline: none;
    -webkit-appearance: none; /* Flat styling for selects on iOS */
}

input:focus, select:focus {
    border-color: var(--primary-color);
}

/* Buttons */
.btn {
    display: inline-block;
    padding: 0.75rem 1rem;
    font-size: 1rem;
    font-weight: 600;
    border: none;
    cursor: pointer;
    text-align: center;
    border-radius: 0;
    width: 100%;
    text-transform: uppercase;
}

.btn-primary { background-color: var(--primary-color); color: #fff; }
.btn-primary:active { background-color: #333; }

.btn-secondary { background-color: var(--secondary-color); color: var(--text-primary); border: 1px solid var(--border-color); }
.btn-secondary:active { background-color: #d3d3d3; }

.btn-danger { background-color: var(--danger-color); color: #fff; }

.btn-outline { background-color: transparent; border: 1px solid #fff; color: #fff; width: auto; padding: 0.5rem 1rem; }
.btn-outline:active { background-color: #fff; color: var(--primary-color); }

/* Tables for Data (Mobile optimized with horizontal scroll) */
.table-container {
    overflow-x: auto;
    width: 100%;
}

.data-table {
    width: 100%;
    border-collapse: collapse;
    font-size: 0.85rem;
}

.data-table th, .data-table td {
    padding: 0.75rem;
    border: 1px solid var(--border-color);
    text-align: left;
}

.data-table th {
    background-color: var(--secondary-color);
    font-weight: 600;
    text-transform: uppercase;
}

.agent-stamp {
    font-family: monospace;
    color: var(--accent-color);
}

.hidden { display: none !important; }