:root {
    --primary: #046bd2;
    --primary-hover: #045cb4;
    --text-dark: #1e293b;
    --text-secondary: #334155;
    --bg-white: #ffffff;
    --bg-light: #F0F5FA;
    --border: #D1D5DB;
    --gray: #9CA3AF;
    --red: #dc2626;
    --green: #16a34a;
    --font: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen-Sans, Ubuntu, Cantarell, 'Helvetica Neue', sans-serif;
}

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

body {
    font-family: var(--font);
    color: var(--text-dark);
    background: var(--bg-light);
    line-height: 1.5;
}

/* ── Navbar ── */
.navbar {
    background: var(--primary);
    color: white;
    display: flex;
    align-items: center;
    padding: 0 2rem;
    height: 60px;
    box-shadow: 0 2px 8px rgba(0,0,0,0.15);
    position: sticky;
    top: 0;
    z-index: 100;
}
.navbar img { height: 36px; margin-right: 0.75rem; border-radius: 4px; }
.navbar .brand { font-size: 1.2rem; font-weight: 600; margin-right: 2rem; }
.navbar nav a {
    color: rgba(255,255,255,0.85);
    text-decoration: none;
    padding: 0.5rem 1rem;
    border-radius: 6px;
    font-size: 0.9rem;
    transition: background 0.2s;
}
.navbar nav a:hover, .navbar nav a.active {
    background: rgba(255,255,255,0.15);
    color: white;
}

/* ── Page container ── */
.container {
    max-width: 1400px;
    margin: 0 auto;
    padding: 1.5rem 2rem;
}

.page-title {
    font-size: 1.5rem;
    font-weight: 600;
    margin-bottom: 1.5rem;
    color: var(--text-dark);
}
.page-subtitle {
    font-size: 0.95rem;
    color: var(--text-secondary);
    margin-top: -1rem;
    margin-bottom: 1.5rem;
}

/* ── KPI Cards ── */
.kpi-row {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(180px, 1fr));
    gap: 1rem;
    margin-bottom: 1.5rem;
}
.kpi-card {
    background: var(--bg-white);
    border-radius: 10px;
    padding: 1.25rem;
    box-shadow: 0 1px 4px rgba(0,0,0,0.08);
    text-align: center;
}
.kpi-card .kpi-value {
    font-size: 1.8rem;
    font-weight: 700;
    color: var(--primary);
    line-height: 1.2;
}
.kpi-card .kpi-label {
    font-size: 0.8rem;
    color: var(--text-secondary);
    margin-top: 0.25rem;
    text-transform: uppercase;
    letter-spacing: 0.5px;
}

/* ── Filters ── */
.filters-row {
    display: flex;
    align-items: center;
    gap: 1rem;
    margin-bottom: 1.5rem;
    flex-wrap: wrap;
    background: var(--bg-white);
    padding: 1rem 1.25rem;
    border-radius: 10px;
    box-shadow: 0 1px 4px rgba(0,0,0,0.08);
}
.filters-row label {
    font-size: 0.8rem;
    font-weight: 600;
    color: var(--text-secondary);
    text-transform: uppercase;
    letter-spacing: 0.3px;
}
.filters-row select {
    padding: 0.4rem 0.6rem;
    border: 1px solid var(--border);
    border-radius: 6px;
    font-family: var(--font);
    font-size: 0.85rem;
    color: var(--text-dark);
    background: var(--bg-white);
    min-width: 180px;
    max-width: 320px;
}
.filters-row select:focus { outline: 2px solid var(--primary); border-color: var(--primary); }
.btn-reset {
    padding: 0.4rem 1rem;
    background: var(--bg-light);
    border: 1px solid var(--border);
    border-radius: 6px;
    cursor: pointer;
    font-size: 0.85rem;
    color: var(--text-secondary);
    transition: background 0.2s;
}
.btn-reset:hover { background: var(--border); }

/* ── Chart grid ── */
.chart-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 1.5rem;
    margin-bottom: 1.5rem;
}
.chart-grid.full { grid-template-columns: 1fr; }
.chart-card {
    background: var(--bg-white);
    border-radius: 10px;
    padding: 1.25rem;
    box-shadow: 0 1px 4px rgba(0,0,0,0.08);
}
.chart-card h3 {
    font-size: 0.95rem;
    font-weight: 600;
    color: var(--text-dark);
    margin-bottom: 0.75rem;
}

/* ── Info bar ── */
.info-bar {
    background: #fef2f2;
    border: 1px solid #fecaca;
    border-radius: 8px;
    padding: 0.6rem 1rem;
    margin-bottom: 1.5rem;
    font-size: 0.85rem;
    color: var(--red);
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

/* ── Footer ── */
.footer {
    text-align: center;
    padding: 2rem;
    font-size: 0.8rem;
    color: var(--gray);
}
.footer a { color: var(--primary); text-decoration: none; }

/* ── Responsive ── */
@media (max-width: 900px) {
    .chart-grid { grid-template-columns: 1fr; }
    .navbar { padding: 0 1rem; }
    .container { padding: 1rem; }
}
@media (max-width: 600px) {
    .kpi-row { grid-template-columns: repeat(2, 1fr); }
    .filters-row { flex-direction: column; align-items: stretch; }
    .filters-row select { max-width: 100%; }
}

/* ── Data tables ── */
.data-table {
    width: 100%;
    border-collapse: collapse;
    font-size: 0.85rem;
    margin-top: 0.5rem;
}
.data-table th {
    background: var(--primary);
    color: white;
    padding: 0.6rem 0.75rem;
    text-align: left;
    font-weight: 600;
    font-size: 0.8rem;
    text-transform: uppercase;
    letter-spacing: 0.3px;
}
.data-table td {
    padding: 0.5rem 0.75rem;
    border-bottom: 1px solid var(--border);
    text-align: center;
}
.data-table tr:nth-child(even) { background: var(--bg-light); }
.data-table tr:last-child { border-bottom: 2px solid var(--primary); }
.data-table td.num { font-variant-numeric: tabular-nums; }
.data-table td.left { text-align: left; }
.data-table .highlight { background: #fef2f2; font-weight: 600; }

/* Sortable columns */
.data-table th { cursor: pointer; user-select: none; position: relative; text-align: center; }
.data-table th:hover { background: var(--primary-hover); }
.data-table th .sort-arrow { margin-left: 4px; font-size: 0.7rem; opacity: 0.6; }
.data-table th.sort-asc .sort-arrow::after { content: ' ▲'; }
.data-table th.sort-desc .sort-arrow::after { content: ' ▼'; }

/* Regression table */
.reg-table { width: 100%; border-collapse: collapse; font-size: 0.85rem; }
.reg-table th { background: var(--bg-light); padding: 0.5rem; text-align: center; border-bottom: 2px solid var(--primary); font-weight: 600; }
.reg-table td { padding: 0.4rem 0.6rem; border-bottom: 1px solid var(--border); text-align: center; }
.reg-table td:first-child { text-align: left; font-weight: 500; }
.reg-table .sig { color: var(--red); font-weight: 700; }
.reg-stat { font-size: 0.85rem; color: var(--text-secondary); margin-top: 0.75rem; }

/* ── Section headers ── */
.section-title {
    font-size: 1.1rem;
    font-weight: 600;
    color: var(--text-dark);
    margin: 2rem 0 1rem;
    padding-bottom: 0.5rem;
    border-bottom: 2px solid var(--primary);
}

/* ── Loading spinner ── */
.loading {
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 4rem;
    color: var(--gray);
    font-size: 1rem;
}
.loading::before {
    content: '';
    width: 24px; height: 24px;
    border: 3px solid var(--border);
    border-top-color: var(--primary);
    border-radius: 50%;
    animation: spin 0.8s linear infinite;
    margin-right: 0.75rem;
}
@keyframes spin { to { transform: rotate(360deg); } }

/* ── Estimator form ── */
.estimator-form {
    display: flex;
    gap: 1.5rem;
    align-items: flex-end;
    flex-wrap: wrap;
}
.form-group {
    display: flex;
    flex-direction: column;
    gap: 0.4rem;
    flex: 1;
    min-width: 180px;
}
.form-group label {
    font-size: 0.8rem;
    font-weight: 600;
    color: var(--text-secondary);
    text-transform: uppercase;
    letter-spacing: 0.3px;
}
.form-group select, .form-group input {
    padding: 0.5rem 0.75rem;
    border: 1px solid var(--border);
    border-radius: 6px;
    font-family: var(--font);
    font-size: 0.9rem;
    color: var(--text-dark);
    background: var(--bg-white);
}
.form-group select:focus, .form-group input:focus {
    outline: 2px solid var(--primary);
    border-color: var(--primary);
}
.btn-estimate {
    padding: 0.5rem 1.5rem;
    background: var(--primary);
    color: white;
    border: none;
    border-radius: 6px;
    font-family: var(--font);
    font-size: 0.9rem;
    font-weight: 600;
    cursor: pointer;
    transition: background 0.2s;
    height: fit-content;
}
.btn-estimate:hover { background: var(--primary-hover); }
/* Searchable dropdown */
.searchable-select { position: relative; }
.searchable-select input[type="text"] {
    width: 100%;
    padding: 0.5rem 0.75rem;
    border: 1px solid var(--border);
    border-radius: 6px;
    font-family: var(--font);
    font-size: 0.9rem;
    color: var(--text-dark);
    background: var(--bg-white);
}
.searchable-select input[type="text"]:focus {
    outline: 2px solid var(--primary);
    border-color: var(--primary);
}
.dropdown-list {
    display: none;
    position: absolute;
    top: 100%;
    left: 0;
    right: 0;
    max-height: 220px;
    overflow-y: auto;
    background: var(--bg-white);
    border: 1px solid var(--border);
    border-top: none;
    border-radius: 0 0 6px 6px;
    z-index: 50;
    box-shadow: 0 4px 12px rgba(0,0,0,0.1);
}
.dropdown-list.open { display: block; }
.dropdown-item {
    padding: 0.4rem 0.75rem;
    font-size: 0.85rem;
    cursor: pointer;
    color: var(--text-dark);
}
.dropdown-item:hover, .dropdown-item.highlighted {
    background: var(--bg-light);
    color: var(--primary);
}
.dropdown-item.selected {
    background: #eff6ff;
    font-weight: 600;
}
.searchable-select .selected-tag {
    font-size: 0.75rem;
    color: var(--primary);
    margin-top: 0.2rem;
}
@media (max-width: 600px) {
    .estimator-form { flex-direction: column; }
}