:root {
    --bg-main: #1E1E1E;
    --bg-panel: #252526;
    --bg-elevated: #2D2D30;
    --border: #3E3E42;
    --text-primary: #E6E6E6;
    --text-secondary: #9E9E9E;
    --accent: #0E639C;
    --accent-hover: #1177BB;
    --success: #16A34A;
    --warning: #FFB900;
    --danger: #DC2626;
}

body {
    margin: 0;
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    background-color: var(--bg-main);
    color: var(--text-primary);
}

a {
    color: var(--accent);
    text-decoration: none;
}

a:hover {
    text-decoration: underline;
}

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

/* Auth / Center Form */
.center-box {
    display: flex;
    justify-content: center;
    align-items: center;
    min-height: 100vh;
}

.login-form {
    background-color: var(--bg-panel);
    padding: 2rem;
    border-radius: 8px;
    box-shadow: 0 4px 6px rgba(0,0,0,0.3);
    width: 100%;
    max-width: 400px;
}

.login-form h1 {
    margin-top: 0;
    text-align: center;
    color: var(--text-primary);
}

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

.form-group label {
    display: block;
    margin-bottom: 0.5rem;
    color: var(--text-secondary);
}

.form-control {
    width: 100%;
    padding: 0.75rem;
    box-sizing: border-box;
    background-color: var(--bg-main);
    border: 1px solid var(--border);
    color: var(--text-primary);
    border-radius: 4px;
}

.form-control:focus {
    outline: none;
    border-color: var(--accent);
}

.btn {
    display: inline-block;
    padding: 0.75rem 1.5rem;
    background-color: var(--accent);
    color: white;
    border: none;
    border-radius: 4px;
    cursor: pointer;
    font-size: 1rem;
    text-align: center;
    text-decoration: none;
}

.btn:hover {
    background-color: var(--accent-hover);
    text-decoration: none;
}

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

.btn-danger:hover {
    background-color: #b91c1c;
}

.error-message {
    color: var(--danger);
    margin-bottom: 1rem;
    text-align: center;
}

/* Header */
.header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 2rem;
    padding-bottom: 1rem;
    border-bottom: 1px solid var(--border);
}

/* Upload area */
.drop-zone {
    border: 2px dashed var(--border);
    border-radius: 8px;
    padding: 4rem 2rem;
    text-align: center;
    background-color: var(--bg-panel);
    cursor: pointer;
    margin-bottom: 2rem;
    transition: border-color 0.3s;
}

.drop-zone:hover, .drop-zone.dragover {
    border-color: var(--accent);
    background-color: var(--bg-elevated);
}

/* Datasets List */
.dataset-list {
    display: flex;
    flex-direction: column;
    gap: 1rem;
}

.dataset-item {
    display: flex;
    justify-content: space-between;
    align-items: center;
    background-color: var(--bg-panel);
    padding: 1rem;
    border-radius: 8px;
    border: 1px solid var(--border);
}

.dataset-actions {
    display: flex;
    gap: 0.5rem;
}

/* Dashboard */
.kpi-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(200px, 1fr));
    gap: 1rem;
    margin-bottom: 2rem;
}

.kpi-card {
    background-color: var(--bg-panel);
    padding: 1.5rem;
    border-radius: 8px;
    border: 1px solid var(--border);
    box-shadow: 0 2px 4px rgba(0,0,0,0.1);
}

.kpi-title {
    color: var(--text-secondary);
    font-size: 0.875rem;
    margin-bottom: 0.5rem;
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

.kpi-value {
    font-size: 1.5rem;
    font-weight: bold;
}

.kpi-stats {
    font-size: 0.75rem;
    color: var(--text-secondary);
    margin-top: 0.5rem;
}

.charts-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(400px, 1fr));
    gap: 1.5rem;
    margin-bottom: 2rem;
}

.chart-panel {
    background-color: var(--bg-panel);
    padding: 1.5rem;
    border-radius: 8px;
    border: 1px solid var(--border);
}

.chart-panel h3 {
    margin-top: 0;
    margin-bottom: 1rem;
    font-size: 1.1rem;
}

.tables-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
    gap: 1.5rem;
}

table {
    width: 100%;
    border-collapse: collapse;
}

th, td {
    padding: 0.5rem;
    text-align: left;
    border-bottom: 1px solid var(--border);
}

th {
    color: var(--text-secondary);
    font-weight: normal;
}

@media (max-width: 768px) {
    .charts-grid, .tables-grid {
        grid-template-columns: 1fr;
    }
}