/* ===========================
   CSV Pivot Table — Premium Styles
   =========================== */

/* --- CSS Custom Properties --- */
:root {
  --font: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
  --radius: 12px;
  --radius-sm: 8px;
  --radius-xs: 6px;
  --transition: 0.2s cubic-bezier(0.4, 0, 0.2, 1);
  --shadow-sm: 0 1px 3px rgba(0,0,0,0.08);
  --shadow-md: 0 4px 12px rgba(0,0,0,0.12);
  --shadow-lg: 0 8px 32px rgba(0,0,0,0.18);
}

[data-theme="dark"] {
  --bg-primary: #0B0D13;
  --bg-secondary: #12151E;
  --bg-tertiary: #1A1E2E;
  --bg-card: rgba(26, 30, 46, 0.7);
  --bg-hover: rgba(108, 99, 255, 0.08);
  --border: rgba(255,255,255,0.06);
  --border-active: rgba(108, 99, 255, 0.4);
  --text-primary: #F0F0F5;
  --text-secondary: #8B8FA3;
  --text-muted: #555977;
  --accent: #6C63FF;
  --accent-light: #A78BFA;
  --accent-glow: rgba(108, 99, 255, 0.15);
  --success: #34D399;
  --warning: #FBBF24;
  --error: #F87171;
  --info: #38BDF8;
  --glass: rgba(26, 30, 46, 0.6);
  --glass-border: rgba(255,255,255,0.08);
  --field-row: #6C63FF;
  --field-col: #38BDF8;
  --field-val: #34D399;
  --field-filter: #FBBF24;
}

[data-theme="light"] {
  --bg-primary: #F8F9FC;
  --bg-secondary: #FFFFFF;
  --bg-tertiary: #F0F1F5;
  --bg-card: rgba(255, 255, 255, 0.8);
  --bg-hover: rgba(108, 99, 255, 0.06);
  --border: rgba(0,0,0,0.08);
  --border-active: rgba(108, 99, 255, 0.4);
  --text-primary: #1A1D2E;
  --text-secondary: #64687C;
  --text-muted: #9CA0B4;
  --accent: #6C63FF;
  --accent-light: #8B83FF;
  --accent-glow: rgba(108, 99, 255, 0.1);
  --success: #059669;
  --warning: #D97706;
  --error: #DC2626;
  --info: #0284C7;
  --glass: rgba(255, 255, 255, 0.7);
  --glass-border: rgba(0,0,0,0.06);
  --field-row: #6C63FF;
  --field-col: #0284C7;
  --field-val: #059669;
  --field-filter: #D97706;
}

/* --- Reset & Base --- */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }

html { font-size: 16px; -webkit-font-smoothing: antialiased; -moz-osx-font-smoothing: grayscale; }

body {
  font-family: var(--font);
  background: var(--bg-primary);
  color: var(--text-primary);
  min-height: 100vh;
  transition: background var(--transition), color var(--transition);
  line-height: 1.6;
}

/* --- Header --- */
.header {
  position: sticky;
  top: 0;
  z-index: 100;
  background: var(--glass);
  backdrop-filter: blur(20px);
  -webkit-backdrop-filter: blur(20px);
  border-bottom: 1px solid var(--glass-border);
}

.header-content {
  max-width: 1400px;
  margin: 0 auto;
  padding: 0.75rem 1.5rem;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.logo { display: flex; align-items: center; gap: 0.75rem; }
.logo-icon { flex-shrink: 0; }
.logo-text { font-size: 1.125rem; font-weight: 700; letter-spacing: -0.02em; background: linear-gradient(135deg, var(--accent), var(--accent-light)); -webkit-background-clip: text; -webkit-text-fill-color: transparent; background-clip: text; }

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

/* --- Buttons --- */
.icon-btn {
  width: 36px; height: 36px;
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  background: var(--bg-card);
  color: var(--text-secondary);
  cursor: pointer;
  display: flex; align-items: center; justify-content: center;
  transition: all var(--transition);
}
.icon-btn:hover { background: var(--bg-hover); color: var(--accent); border-color: var(--border-active); }
.icon-btn:focus-visible { outline: 2px solid var(--accent); outline-offset: 2px; }

.btn {
  display: inline-flex; align-items: center; gap: 0.5rem;
  padding: 0.5rem 1rem;
  border-radius: var(--radius-sm);
  font-family: var(--font);
  font-size: 0.8125rem;
  font-weight: 500;
  cursor: pointer;
  transition: all var(--transition);
  border: 1px solid transparent;
}
.btn-ghost { background: var(--bg-card); border-color: var(--border); color: var(--text-secondary); }
.btn-ghost:hover { background: var(--bg-hover); color: var(--accent); border-color: var(--border-active); }
.btn-ghost:disabled { opacity: 0.4; cursor: not-allowed; }
.btn-ghost:disabled:hover { background: var(--bg-card); color: var(--text-secondary); border-color: var(--border); }
.btn-sm { padding: 0.375rem 0.75rem; font-size: 0.75rem; }
.btn:focus-visible { outline: 2px solid var(--accent); outline-offset: 2px; }

/* --- Theme toggle icons --- */
[data-theme="dark"] .sun-icon { display: block; }
[data-theme="dark"] .moon-icon { display: none; }
[data-theme="light"] .sun-icon { display: none; }
[data-theme="light"] .moon-icon { display: block; }

/* --- Main --- */
.main {
  max-width: 1400px;
  margin: 0 auto;
  padding: 1.5rem;
}

/* --- Upload Section --- */
.upload-section {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  min-height: 60vh;
  gap: 1.5rem;
}

.upload-zone {
  width: 100%;
  max-width: 560px;
  padding: 3rem 2rem;
  border: 2px dashed var(--border);
  border-radius: var(--radius);
  background: var(--bg-card);
  backdrop-filter: blur(12px);
  text-align: center;
  cursor: pointer;
  transition: all var(--transition);
}
.upload-zone:hover, .upload-zone.drag-over {
  border-color: var(--accent);
  background: var(--accent-glow);
  transform: translateY(-2px);
  box-shadow: var(--shadow-lg), 0 0 40px var(--accent-glow);
}
.upload-zone:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 4px;
}

.upload-icon { color: var(--text-muted); margin-bottom: 1rem; transition: color var(--transition); }
.upload-zone:hover .upload-icon { color: var(--accent); }

.upload-text { font-size: 1rem; color: var(--text-secondary); margin-bottom: 0.5rem; }
.upload-link { color: var(--accent); font-weight: 600; text-decoration: underline; text-underline-offset: 3px; }
.upload-hint { font-size: 0.8125rem; color: var(--text-muted); }

.sample-data { text-align: center; }

/* --- Workspace --- */
.hidden { display: none !important; }

.file-info-bar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0.75rem 1rem;
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  margin-bottom: 1rem;
  backdrop-filter: blur(12px);
}
.file-info { display: flex; align-items: center; gap: 1rem; flex-wrap: wrap; }
.file-name { font-weight: 600; font-size: 0.875rem; color: var(--text-primary); }
.file-stats { font-size: 0.75rem; color: var(--text-muted); }

/* --- Pivot Builder --- */
.pivot-builder {
  display: grid;
  grid-template-columns: 200px 1fr;
  gap: 1rem;
  margin-bottom: 1rem;
}

.section-title, .zone-title {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  font-size: 0.75rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--text-muted);
  margin-bottom: 0.75rem;
}

.field-pool {
  padding: 1rem;
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  backdrop-filter: blur(12px);
  max-height: 400px;
  overflow-y: auto;
}

.field-list { display: flex; flex-direction: column; gap: 0.375rem; }

.field-chip {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.5rem 0.75rem;
  border-radius: var(--radius-xs);
  font-size: 0.8125rem;
  font-weight: 500;
  cursor: grab;
  transition: all var(--transition);
  border: 1px solid var(--border);
  background: var(--bg-secondary);
  color: var(--text-primary);
  user-select: none;
}
.field-chip:hover {
  border-color: var(--border-active);
  background: var(--bg-hover);
  transform: translateX(3px);
}
.field-chip:active { cursor: grabbing; }
.field-chip.dragging { opacity: 0.5; transform: scale(0.95); }

.field-chip .field-type-icon {
  width: 6px; height: 6px;
  border-radius: 50%;
  flex-shrink: 0;
}
.field-chip[data-type="number"] .field-type-icon { background: var(--field-val); }
.field-chip[data-type="string"] .field-type-icon { background: var(--field-row); }
.field-chip[data-type="date"] .field-type-icon { background: var(--field-col); }

/* --- Drop Zones --- */
.drop-zones {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 0.75rem;
}

.drop-zone {
  padding: 0.875rem 1rem;
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  backdrop-filter: blur(12px);
  min-height: 80px;
  transition: all var(--transition);
}
.drop-zone.drag-over {
  border-color: var(--accent);
  background: var(--accent-glow);
  box-shadow: inset 0 0 20px var(--accent-glow);
}

.zone-fields { display: flex; flex-wrap: wrap; gap: 0.375rem; min-height: 28px; }
.zone-hint { font-size: 0.75rem; color: var(--text-muted); font-style: italic; margin-top: 0.25rem; }
.drop-zone .zone-hint { display: block; }
.drop-zone:has(.zone-chip) .zone-hint { display: none; }

.zone-chip {
  display: inline-flex;
  align-items: center;
  gap: 0.375rem;
  padding: 0.375rem 0.625rem;
  border-radius: var(--radius-xs);
  font-size: 0.75rem;
  font-weight: 500;
  cursor: grab;
  transition: all var(--transition);
  color: white;
}
.zone-chip:active { cursor: grabbing; }

.zone-chip[data-zone="rows"] { background: var(--field-row); }
.zone-chip[data-zone="columns"] { background: var(--field-col); }
.zone-chip[data-zone="values"] { background: var(--field-val); }
.zone-chip[data-zone="filters"] { background: var(--field-filter); }

.zone-chip .remove-btn {
  width: 16px; height: 16px;
  border: none;
  background: rgba(255,255,255,0.2);
  color: white;
  border-radius: 50%;
  cursor: pointer;
  display: flex; align-items: center; justify-content: center;
  font-size: 10px;
  line-height: 1;
  transition: background var(--transition);
}
.zone-chip .remove-btn:hover { background: rgba(255,255,255,0.4); }

/* Value aggregation selector */
.zone-chip select {
  background: rgba(255,255,255,0.2);
  border: none;
  color: white;
  font-size: 0.6875rem;
  font-family: var(--font);
  border-radius: 4px;
  padding: 0 0.25rem;
  cursor: pointer;
  outline: none;
}
.zone-chip select option { color: #1A1D2E; }

/* --- Pivot Output --- */
.pivot-output {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  backdrop-filter: blur(12px);
  overflow: hidden;
}

.output-toolbar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0.75rem 1rem;
  border-bottom: 1px solid var(--border);
  flex-wrap: wrap;
  gap: 0.5rem;
}
.pivot-status { font-size: 0.8125rem; color: var(--text-muted); }
.output-actions { display: flex; gap: 0.5rem; }

.table-container {
  overflow: auto;
  max-height: 60vh;
}

.empty-state {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  padding: 4rem 2rem;
  text-align: center;
  gap: 1rem;
}
.empty-state p { font-size: 0.875rem; color: var(--text-muted); max-width: 360px; line-height: 1.6; }

/* --- Pivot Table --- */
.pivot-table {
  width: 100%;
  border-collapse: collapse;
  font-size: 0.8125rem;
}
.pivot-table th, .pivot-table td {
  padding: 0.5rem 0.75rem;
  border: 1px solid var(--border);
  text-align: left;
  white-space: nowrap;
}
.pivot-table th {
  background: var(--bg-tertiary);
  font-weight: 600;
  color: var(--text-secondary);
  position: sticky;
  top: 0;
  z-index: 2;
  font-size: 0.75rem;
  text-transform: uppercase;
  letter-spacing: 0.04em;
}
.pivot-table td { color: var(--text-primary); }
.pivot-table td.number-cell { text-align: right; font-variant-numeric: tabular-nums; }
.pivot-table tbody tr:hover { background: var(--bg-hover); }
.pivot-table .total-row { font-weight: 700; background: var(--bg-tertiary); }
.pivot-table .col-header { background: linear-gradient(135deg, var(--bg-tertiary), var(--bg-secondary)); }
.pivot-table th.sortable { cursor: pointer; user-select: none; }
.pivot-table th.sortable:hover { color: var(--accent); }
.pivot-table th .sort-indicator { margin-left: 0.25rem; font-size: 0.625rem; }

/* --- Filter Popover --- */
.filter-popover {
  position: fixed;
  z-index: 200;
  background: var(--bg-secondary);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  box-shadow: var(--shadow-lg);
  padding: 1rem;
  min-width: 220px;
  max-height: 300px;
  overflow-y: auto;
}
.filter-popover h4 { font-size: 0.75rem; font-weight: 600; color: var(--text-muted); margin-bottom: 0.5rem; text-transform: uppercase; letter-spacing: 0.06em; }
.filter-option { display: flex; align-items: center; gap: 0.5rem; padding: 0.25rem 0; font-size: 0.8125rem; color: var(--text-primary); cursor: pointer; }
.filter-option input { accent-color: var(--accent); }

/* --- Modal --- */
.modal {
  position: fixed;
  inset: 0;
  z-index: 1000;
  display: flex;
  align-items: center;
  justify-content: center;
}
.modal-backdrop {
  position: absolute;
  inset: 0;
  background: rgba(0,0,0,0.5);
  backdrop-filter: blur(4px);
}
.modal-content {
  position: relative;
  background: var(--bg-secondary);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  box-shadow: var(--shadow-lg);
  padding: 1.5rem;
  min-width: 360px;
  max-width: 90vw;
  animation: modalIn 0.25s ease;
}
@keyframes modalIn {
  from { opacity: 0; transform: scale(0.95) translateY(8px); }
  to { opacity: 1; transform: scale(1) translateY(0); }
}
.modal-header { display: flex; align-items: center; justify-content: space-between; margin-bottom: 1.25rem; }
.modal-header h2 { font-size: 1rem; font-weight: 700; }

.shortcut-group { margin-bottom: 1rem; }
.shortcut-group h3 { font-size: 0.6875rem; font-weight: 600; text-transform: uppercase; letter-spacing: 0.08em; color: var(--text-muted); margin-bottom: 0.5rem; }
.shortcut { display: flex; align-items: center; justify-content: space-between; padding: 0.375rem 0; }
.shortcut kbd {
  display: inline-flex; align-items: center; justify-content: center;
  min-width: 28px; padding: 0.125rem 0.5rem;
  background: var(--bg-tertiary);
  border: 1px solid var(--border);
  border-radius: 4px;
  font-family: var(--font);
  font-size: 0.6875rem;
  font-weight: 600;
  color: var(--text-secondary);
}
.shortcut span { font-size: 0.8125rem; color: var(--text-secondary); }

/* --- Toast --- */
.toast-container {
  position: fixed;
  bottom: 1.5rem;
  right: 1.5rem;
  z-index: 2000;
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
}
.toast {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  padding: 0.75rem 1rem;
  border-radius: var(--radius-sm);
  background: var(--bg-secondary);
  border: 1px solid var(--border);
  box-shadow: var(--shadow-lg);
  font-size: 0.8125rem;
  color: var(--text-primary);
  animation: toastIn 0.3s ease, toastOut 0.3s ease 2.7s forwards;
  max-width: 320px;
}
.toast.success { border-left: 3px solid var(--success); }
.toast.error { border-left: 3px solid var(--error); }
.toast.info { border-left: 3px solid var(--info); }

@keyframes toastIn {
  from { opacity: 0; transform: translateX(20px); }
  to { opacity: 1; transform: translateX(0); }
}
@keyframes toastOut {
  from { opacity: 1; transform: translateX(0); }
  to { opacity: 0; transform: translateX(20px); }
}

/* --- Responsive --- */
@media (max-width: 768px) {
  .main { padding: 1rem; }
  .pivot-builder { grid-template-columns: 1fr; }
  .drop-zones { grid-template-columns: 1fr; }
  .upload-zone { padding: 2rem 1.25rem; }
  .file-info-bar { flex-direction: column; gap: 0.5rem; align-items: flex-start; }
  .output-toolbar { flex-direction: column; align-items: flex-start; }
  .modal-content { min-width: auto; margin: 1rem; }
}

@media (max-width: 480px) {
  .header-content { padding: 0.75rem 1rem; }
  .logo-text { font-size: 0.9375rem; }
}

/* --- Scrollbar --- */
::-webkit-scrollbar { width: 6px; height: 6px; }
::-webkit-scrollbar-track { background: transparent; }
::-webkit-scrollbar-thumb { background: var(--text-muted); border-radius: 3px; }
::-webkit-scrollbar-thumb:hover { background: var(--text-secondary); }