:root {
    --primary: #0d9488;
    --primary-dark: #0f766e;
    --primary-light: #ccfbf1;
    --secondary: #065f46;
    --accent: #f59e0b;
    --text: #1e293b;
    --text-light: #475569;
    --bg: #f1f5f9;
    --white: #ffffff;
    --border: #e2e8f0;
    --danger: #ef4444;
    --success: #22c55e;
    --radius: 8px;
    --shadow: 0 1px 3px rgba(0, 0, 0, 0.1), 0 1px 2px rgba(0, 0, 0, 0.06);
    --shadow-md: 0 4px 6px rgba(0, 0, 0, 0.07), 0 2px 4px rgba(0, 0, 0, 0.06);
}

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

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    background: var(--bg);
    min-height: 100vh;
    color: var(--text);
}

.hidden {
    display: none !important;
}

/* ---- Buttons ---- */
.btn {
    display: inline-flex;
    align-items: center;
    gap: 6px;
    padding: 10px 18px;
    border: none;
    border-radius: var(--radius);
    font-size: 0.95rem;
    font-family: inherit;
    cursor: pointer;
    transition: background 0.2s, transform 0.1s;
}

.btn:active {
    transform: scale(0.97);
}

.btn-primary {
    background: var(--primary);
    color: var(--white);
}

.btn-primary:hover {
    background: var(--primary-dark);
}

.btn-block {
    width: 100%;
    justify-content: center;
}

.btn-logout {
    background: transparent;
    color: var(--white);
    border: 1px solid rgba(255, 255, 255, 0.4);
}

.btn-logout:hover {
    background: rgba(255, 255, 255, 0.15);
}

.btn-filter {
    align-self: flex-end;
}

/* ---- Login Screen ---- */
.login-screen {
    display: flex;
    align-items: center;
    justify-content: center;
    min-height: 100vh;
    background: linear-gradient(135deg, var(--primary) 0%, var(--secondary) 100%);
    padding: 20px;
}

.login-card {
    background: var(--white);
    border-radius: 12px;
    padding: 40px;
    width: 100%;
    max-width: 400px;
    box-shadow: var(--shadow-md);
    text-align: center;
}

.login-card h1 {
    color: var(--primary);
    margin-bottom: 6px;
    font-size: 1.5rem;
}

.login-subtitle {
    color: var(--text-light);
    margin-bottom: 28px;
    font-size: 0.95rem;
}

.form-group {
    margin-bottom: 16px;
    text-align: left;
}

.form-group label {
    display: block;
    margin-bottom: 4px;
    font-weight: 600;
    font-size: 0.875rem;
    color: var(--text);
}

.form-group input,
.form-group select {
    width: 100%;
    padding: 10px 12px;
    border: 1px solid var(--border);
    border-radius: var(--radius);
    font-size: 0.95rem;
    font-family: inherit;
    transition: border-color 0.2s;
}

.form-group input:focus,
.form-group select:focus {
    outline: none;
    border-color: var(--primary);
    box-shadow: 0 0 0 3px rgba(13, 148, 136, 0.15);
}

.login-error {
    background: #fef2f2;
    color: var(--danger);
    padding: 10px;
    border-radius: var(--radius);
    font-size: 0.875rem;
    margin-bottom: 12px;
}

/* ---- Dashboard Layout ---- */
.dashboard {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px 40px;
}

.dashboard-header {
    background: linear-gradient(135deg, var(--primary), var(--secondary));
    color: var(--white);
    padding: 20px 28px;
    border-radius: 0 0 12px 12px;
    display: flex;
    align-items: center;
    justify-content: space-between;
    margin-bottom: 20px;
    box-shadow: var(--shadow);
}

.dashboard-header h1 {
    font-size: 1.35rem;
}

/* ---- Filter Bar ---- */
.filter-bar {
    background: var(--white);
    padding: 16px 20px;
    border-radius: var(--radius);
    display: flex;
    flex-wrap: wrap;
    gap: 16px;
    align-items: flex-end;
    margin-bottom: 20px;
    box-shadow: var(--shadow);
}

.filter-group {
    display: flex;
    flex-direction: column;
    gap: 4px;
}

.filter-group label {
    font-size: 0.8rem;
    font-weight: 600;
    color: var(--text-light);
    text-transform: uppercase;
    letter-spacing: 0.5px;
}

.filter-group select,
.filter-group input {
    padding: 8px 12px;
    border: 1px solid var(--border);
    border-radius: var(--radius);
    font-size: 0.9rem;
    font-family: inherit;
    min-width: 160px;
}

.filter-group select:focus,
.filter-group input:focus {
    outline: none;
    border-color: var(--primary);
    box-shadow: 0 0 0 3px rgba(13, 148, 136, 0.15);
}

/* ---- Tab Navigation ---- */
.tab-nav {
    display: flex;
    gap: 4px;
    margin-bottom: 20px;
    border-bottom: 2px solid var(--border);
    padding-bottom: 0;
}

.tab-btn {
    padding: 12px 20px;
    border: none;
    background: transparent;
    font-size: 0.95rem;
    font-family: inherit;
    color: var(--text-light);
    cursor: pointer;
    border-bottom: 2px solid transparent;
    margin-bottom: -2px;
    transition: color 0.2s, border-color 0.2s;
    display: flex;
    align-items: center;
    gap: 6px;
}

.tab-btn:hover {
    color: var(--primary);
}

.tab-btn.active {
    color: var(--primary);
    border-bottom-color: var(--primary);
    font-weight: 600;
}

/* ---- Tab Content ---- */
.tab-content {
    display: none;
}

.tab-content.active {
    display: block;
}

/* ---- Stats Grid ---- */
.stats-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
    gap: 16px;
}

.stat-card {
    background: var(--white);
    border-radius: var(--radius);
    padding: 24px;
    box-shadow: var(--shadow);
    text-align: center;
}

.stat-card .stat-icon {
    font-size: 1.6rem;
    color: var(--primary);
    margin-bottom: 8px;
}

.stat-card .stat-value {
    font-size: 2rem;
    font-weight: 700;
    color: var(--text);
    line-height: 1.2;
}

.stat-card .stat-label {
    font-size: 0.85rem;
    color: var(--text-light);
    margin-top: 4px;
    text-transform: uppercase;
    letter-spacing: 0.5px;
}

/* ---- Data Table ---- */
.data-table-wrapper {
    background: var(--white);
    border-radius: var(--radius);
    box-shadow: var(--shadow);
    overflow-x: auto;
}

.data-table {
    width: 100%;
    border-collapse: collapse;
    font-size: 0.9rem;
}

.data-table thead {
    background: var(--primary-light);
}

.data-table th {
    padding: 12px 16px;
    text-align: left;
    font-weight: 600;
    color: var(--primary-dark);
    font-size: 0.8rem;
    text-transform: uppercase;
    letter-spacing: 0.5px;
    white-space: nowrap;
}

.data-table td {
    padding: 12px 16px;
    border-bottom: 1px solid var(--border);
}

.data-table tbody tr:nth-child(even) {
    background: #f8fafc;
}

.data-table tbody tr:hover {
    background: var(--primary-light);
}

/* ---- Units / Activity Bars ---- */
.unit-section {
    background: var(--white);
    border-radius: var(--radius);
    padding: 24px;
    margin-bottom: 16px;
    box-shadow: var(--shadow);
}

.unit-section h3 {
    margin-bottom: 16px;
    color: var(--text);
    font-size: 1.05rem;
}

.activity-bar-row {
    display: flex;
    align-items: center;
    margin-bottom: 10px;
    gap: 12px;
}

.activity-bar-label {
    min-width: 140px;
    font-size: 0.875rem;
    color: var(--text);
    text-transform: capitalize;
}

.activity-bar-track {
    flex: 1;
    height: 24px;
    background: var(--bg);
    border-radius: 4px;
    overflow: hidden;
}

.activity-bar-fill {
    height: 100%;
    background: linear-gradient(90deg, var(--primary), var(--primary-dark));
    border-radius: 4px;
    transition: width 0.4s ease;
    min-width: 2px;
}

.activity-bar-count {
    min-width: 40px;
    font-size: 0.85rem;
    color: var(--text-light);
    text-align: right;
}

/* ---- Empty State ---- */
.empty-state {
    text-align: center;
    padding: 48px 20px;
    color: var(--text-light);
}

.empty-state i {
    font-size: 2.5rem;
    margin-bottom: 12px;
    display: block;
    color: var(--border);
}

.empty-state p {
    font-size: 1rem;
}

/* ---- Loading Spinner ---- */
.loading {
    text-align: center;
    padding: 40px;
    color: var(--text-light);
}

.loading i {
    font-size: 1.5rem;
    animation: spin 1s linear infinite;
}

@keyframes spin {
    to { transform: rotate(360deg); }
}

/* ---- Responsive ---- */
@media (max-width: 768px) {
    .dashboard-header {
        flex-direction: column;
        gap: 12px;
        text-align: center;
    }

    .filter-bar {
        flex-direction: column;
    }

    .filter-group select,
    .filter-group input {
        min-width: 100%;
    }

    .tab-btn {
        padding: 10px 14px;
        font-size: 0.85rem;
    }

    .stats-grid {
        grid-template-columns: 1fr 1fr;
    }
}

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

    .login-card {
        padding: 28px 20px;
    }
}