* { box-sizing: border-box; }

body {
    font-family: 'Segoe UI', system-ui, sans-serif;
    background: linear-gradient(135deg, #db983b 0%, #ab57ff 100%);
    min-height: 100vh;
    padding: 20px;
    margin: 0;
}

.container {
    max-width: 1100px;
    margin: 0 auto;
    background: white;
    border-radius: 16px;
    padding: 30px;
    box-shadow: 0 10px 40px rgba(0,0,0,0.2);
}

h1 { color: #333; margin-bottom: 5px; }
.subtitle { color: #666; margin-top: 0; }

.section {
    margin: 25px 0;
    padding: 20px;
    background: #f8f9fa;
    border-radius: 12px;
}

.columns-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 20px;
}

.column-selector {
    background: white;
    padding: 15px;
    border-radius: 8px;
    border: 1px solid #e0e0e0;
    max-height: 250px;
    overflow-y: auto;
}

.checkbox-label {
    display: block;
    padding: 6px 8px;
    margin: 4px 0;
    border-radius: 4px;
    cursor: pointer;
    transition: background 0.2s;
}

.checkbox-label:hover { background: #f0f0f0; }
.checkbox-label input { margin-right: 8px; }
.hint { color: #888; font-size: 0.85em; }

.naming-options {
    display: flex;
    gap: 20px;
    margin-top: 15px;
}

.naming-options input {
    padding: 8px 12px;
    border: 1px solid #ddd;
    border-radius: 6px;
    width: 150px;
}

.quick-select {
    margin-top: 10px;
    display: flex;
    gap: 8px;
}

.quick-select button {
    font-size: 0.8em;
    padding: 5px 10px;
}

.actions {
    display: flex;
    gap: 12px;
    justify-content: center;
    margin: 20px 0;
}

button {
    background: #6c757d;
    color: white;
    border: none;
    padding: 12px 24px;
    border-radius: 8px;
    cursor: pointer;
    font-size: 1em;
    transition: transform 0.1s, background 0.2s;
}

button:hover { background: #5a6268; transform: translateY(-1px); }
button.primary { background: #667eea; }
button.primary:hover { background: #5a6fd6; }
button.danger { background: #dc3545; }

.preview-container { overflow-x: auto; }

table {
    width: 100%;
    border-collapse: collapse;
    font-size: 0.9em;
}

th, td {
    padding: 10px 12px;
    text-align: left;
    border-bottom: 1px solid #eee;
}

th { background: #667eea; color: white; }
tr:hover { background: #f5f5f5; }

.null { color: #999; font-style: italic; }
.info { color: #666; font-size: 0.9em; text-align: center; }
.empty { color: #999; text-align: center; padding: 20px; }

.dataset-list { list-style: none; padding: 0; }
.dataset-list li {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 12px;
    background: white;
    margin: 8px 0;
    border-radius: 8px;
}

.format-badge {
    background: #e0e7ff;
    color: #667eea;
    padding: 2px 8px;
    border-radius: 4px;
    font-size: 0.8em;
}

.status {
    text-align: center;
    padding: 15px;
    color: #555;
    font-weight: 500;
}