:root {
    --primary: #4f46e5;
    --primary-hover: #4338ca;
    --bg: #f3f4f6;
    --card-bg: #ffffff;
    --text-main: #1f2937;
    --text-muted: #6b7280;
    --border: #e5e7eb;
    --danger: #ef4444;
    --success: #10b981;
    --shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -1px rgba(0, 0, 0, 0.06);
    --radius: 8px;
}

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

body {
    font-family: 'Inter', sans-serif;
    background-color: var(--bg);
    color: var(--text-main);
    line-height: 1.5;
}

.container {
    max-width: 1000px;
    margin: 0 auto;
    padding: 0 20px;
}

/* Header */
header {
    background: var(--card-bg);
    border-bottom: 1px solid var(--border);
    padding: 2rem 0;
    margin-bottom: 2rem;
    text-align: center;
}

header h1 {
    font-size: 2rem;
    font-weight: 700;
    color: var(--primary);
    margin-bottom: 0.5rem;
}

header p {
    color: var(--text-muted);
}

/* Common Components */
.card {
    background: var(--card-bg);
    padding: 1.5rem;
    border-radius: var(--radius);
    box-shadow: var(--shadow);
    margin-bottom: 1.5rem;
}

.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    padding: 0.6rem 1.2rem;
    border-radius: 6px;
    font-weight: 500;
    cursor: pointer;
    border: none;
    transition: all 0.2s;
    font-size: 0.95rem;
}

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

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

.btn.primary:disabled {
    background-color: #a5a3e1;
    /* lighter version */
    cursor: not-allowed;
}

.btn.secondary {
    background-color: white;
    border: 1px solid var(--border);
    color: var(--text-main);
}

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

.btn.small {
    padding: 0.4rem 0.8rem;
    font-size: 0.85rem;
}

h2 {
    font-size: 1.25rem;
    margin-bottom: 1rem;
    font-weight: 600;
}

.hidden {
    display: none !important;
}

/* Upload Section */
.upload-area {
    border: 2px dashed var(--border);
    border-radius: var(--radius);
    padding: 3rem;
    text-align: center;
    transition: border-color 0.2s;
    cursor: pointer;
}

.upload-area:hover,
.upload-area.dragover {
    border-color: var(--primary);
    background-color: #f8fafc;
}

.upload-area .icon {
    font-size: 3rem;
    margin-bottom: 1rem;
}

.browse-link {
    color: var(--primary);
    font-weight: 600;
    text-decoration: underline;
}

.file-name {
    margin-top: 1rem;
    font-weight: 600;
    color: var(--success);
}

/* Column Selection */
#column-select {
    width: 100%;
    padding: 0.75rem;
    border: 1px solid var(--border);
    border-radius: 6px;
    margin-bottom: 1rem;
    font-size: 1rem;
    background-color: white;
}

/* Dashboard */
.section-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 1rem;
}

.grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(200px, 1fr));
    gap: 1rem;
    margin-bottom: 3rem;
}

.group-card {
    background: var(--card-bg);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 1rem;
    cursor: pointer;
    transition: transform 0.2s, box-shadow 0.2s, border-color 0.2s;
    position: relative;
    user-select: none;
}

.group-card:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow);
    border-color: var(--primary);
}

.group-card.selected {
    background-color: #e0e7ff;
    border-color: var(--primary);
    box-shadow: 0 0 0 2px var(--primary);
}

.group-card h3 {
    font-size: 1rem;
    margin-bottom: 0.5rem;
    color: var(--text-main);
    word-break: break-word;
}

.group-card .count {
    color: var(--text-muted);
    font-size: 0.9rem;
}

/* Modal */
dialog {
    border: none;
    border-radius: var(--radius);
    box-shadow: 0 10px 25px rgba(0, 0, 0, 0.2);
    width: 90%;
    max-width: 1200px;
    max-height: 90vh;
    margin: auto;
    padding: 0;
}

dialog::backdrop {
    background: rgba(0, 0, 0, 0.5);
}

.modal-header {
    padding: 1.5rem;
    border-bottom: 1px solid var(--border);
    display: flex;
    justify-content: space-between;
    align-items: center;
    position: sticky;
    top: 0;
    background: white;
}

.close-btn {
    background: transparent;
    border: none;
    font-size: 1.5rem;
    cursor: pointer;
    line-height: 1;
    padding: 0.2rem;
}

.modal-body {
    padding: 1.5rem;
    overflow-y: auto;
}

.modal-actions {
    margin-bottom: 1rem;
    text-align: right;
}

/* Table */
.table-wrapper {
    overflow-x: auto;
    border: 1px solid var(--border);
    border-radius: 6px;
}

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

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

th {
    background-color: #f9fafb;
    font-weight: 600;
    white-space: nowrap;
}

footer {
    text-align: center;
    color: var(--text-muted);
    padding: 2rem;
    font-size: 0.85rem;
}

/* Summary Bar */
.summary-bar {
    display: flex;
    justify-content: space-between;
    align-items: center;
    flex-wrap: wrap;
    gap: 1rem;
    padding: 1rem 1.5rem;
    background: white;
    position: sticky;
    top: 10px;
    z-index: 50;
    border: 1px solid var(--primary);
}

.summary-item {
    display: flex;
    align-items: center;
    gap: 0.75rem;
}

.summary-item .label {
    color: var(--text-muted);
    font-size: 0.9rem;
    font-weight: 500;
}

.summary-item .value {
    font-weight: 600;
    color: var(--text-main);
}

#summary-column-select {
    width: auto;
    margin-bottom: 0;
    padding: 0.4rem 2rem 0.4rem 0.6rem;
    /* extra padding for arrow */
}

.btn-link {
    background: none;
    border: none;
    color: var(--primary);
    text-decoration: underline;
    cursor: pointer;
    font-size: 0.85rem;
    padding: 0;
}

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

.btn-icon {
    background: none;
    border: none;
    cursor: pointer;
    font-size: 1.2rem;
    padding: 0;
    margin-left: 0.5rem;
    transition: transform 0.2s;
}

.btn-icon:hover {
    transform: translateY(-2px);
}

.group-card {
    background: var(--card-bg);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 1rem;
    cursor: pointer;
    transition: transform 0.2s, box-shadow 0.2s, border-color 0.2s;
    position: relative;
    /* For absolute delete btn */
    user-select: none;
}

.delete-btn {
    position: absolute;
    top: 8px;
    right: 8px;
    width: 24px;
    height: 24px;
    border-radius: 50%;
    border: none;
    background: transparent;
    color: #9ca3af;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.2rem;
    line-height: 1;
    transition: all 0.2s;
    z-index: 10;
}

.delete-btn:hover {
    background-color: #fee2e2;
    color: var(--danger);
}