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

:root {
  --font: 'Inter', system-ui, sans-serif;

  /* Palette */
  --bg-base:      #0b0e1a;
  --bg-surface:   #111827;
  --bg-panel:     rgba(17, 24, 39, 0.85);
  --bg-card:      rgba(255, 255, 255, 0.04);
  --bg-hover:     rgba(255, 255, 255, 0.07);

  --border:       rgba(255, 255, 255, 0.10);
  --border-focus: rgba(99, 179, 237, 0.60);

  --accent:       #3b82f6;
  --accent-glow:  rgba(59, 130, 246, 0.35);
  --accent-hover: #60a5fa;
  --success:      #10b981;
  --warning:      #f59e0b;
  --danger:       #ef4444;

  --text-primary:   #f0f4ff;
  --text-secondary: #9ba3b8;
  --text-muted:     #5a6380;

  --radius-sm: 6px;
  --radius:    10px;
  --radius-lg: 16px;
  --radius-xl: 22px;

  --shadow-sm: 0 1px 3px rgba(0,0,0,0.4);
  --shadow:    0 4px 16px rgba(0,0,0,0.5);
  --shadow-lg: 0 8px 32px rgba(0,0,0,0.7);

  --transition: 0.18s cubic-bezier(0.4, 0, 0.2, 1);
}

html, body {
  height: 100%;
  font-family: var(--font);
  background-color: var(--bg-base);
  color: var(--text-primary);
  line-height: 1.5;
  -webkit-font-smoothing: antialiased;
}

#root { min-height: 100vh; display: flex; flex-direction: column; }

/* ── Scrollbar ─────────────────────────────────────────────────── */
::-webkit-scrollbar { width: 6px; height: 6px; }
::-webkit-scrollbar-track { background: transparent; }
::-webkit-scrollbar-thumb { background: rgba(255,255,255,0.15); border-radius: 3px; }
::-webkit-scrollbar-thumb:hover { background: rgba(255,255,255,0.25); }

/* ── Layout ────────────────────────────────────────────────────── */
.app {
  display: flex;
  flex-direction: column;
  min-height: 100vh;
}

.app-header {
  padding: 18px 32px;
  border-bottom: 1px solid var(--border);
  background: rgba(11, 14, 26, 0.90);
  backdrop-filter: blur(12px);
  position: sticky;
  top: 0;
  z-index: 100;
  display: flex;
  align-items: center;
  gap: 16px;
}

.app-header-logo {
  display: flex;
  align-items: center;
  gap: 10px;
}

.app-header-logo svg { flex-shrink: 0; }

.app-header h1 {
  font-size: 1.15rem;
  font-weight: 700;
  letter-spacing: -0.01em;
  color: var(--text-primary);
  white-space: nowrap;
}

.app-header-subtitle {
  font-size: 0.8rem;
  color: var(--text-muted);
  margin-top: 1px;
}

.app-badge {
  margin-left: auto;
  padding: 4px 10px;
  background: var(--accent-glow);
  border: 1px solid var(--accent);
  border-radius: 100px;
  font-size: 0.7rem;
  font-weight: 600;
  color: var(--accent-hover);
  letter-spacing: 0.05em;
  text-transform: uppercase;
}

.app-body {
  flex: 1;
  display: grid;
  grid-template-columns: 340px 1fr;
  gap: 0;
  overflow: hidden;
}

.sidebar {
  border-right: 1px solid var(--border);
  overflow-y: auto;
  padding: 24px 20px;
  display: flex;
  flex-direction: column;
  gap: 20px;
  background: linear-gradient(180deg, rgba(17,24,39,0.6) 0%, rgba(11,14,26,0.4) 100%);
}

.preview-area {
  overflow-y: auto;
  padding: 24px 28px;
  display: flex;
  flex-direction: column;
  gap: 24px;
}

/* ── Glass panels ──────────────────────────────────────────────── */
.panel {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  backdrop-filter: blur(8px);
  overflow: hidden;
}

.panel-header {
  display: flex;
  align-items: center;
  gap: 8px;
  padding: 14px 16px;
  border-bottom: 1px solid var(--border);
  background: rgba(255,255,255,0.025);
}

.panel-header-icon {
  width: 28px;
  height: 28px;
  border-radius: var(--radius-sm);
  display: flex;
  align-items: center;
  justify-content: center;
  background: var(--bg-hover);
  color: var(--accent);
  flex-shrink: 0;
}

.panel-title {
  font-size: 0.8rem;
  font-weight: 600;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  color: var(--text-secondary);
}

.panel-body {
  padding: 16px;
  display: flex;
  flex-direction: column;
  gap: 14px;
}

/* ── Upload zone ───────────────────────────────────────────────── */
.upload-zone {
  position: relative;
  min-height: 160px;
  border: 2px dashed var(--border);
  border-radius: var(--radius-lg);
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 10px;
  cursor: pointer;
  transition: border-color var(--transition), background var(--transition), transform var(--transition);
  text-align: center;
  padding: 20px;
  overflow: hidden;
}

.upload-zone::before {
  content: '';
  position: absolute;
  inset: 0;
  background: radial-gradient(ellipse at 50% 100%, var(--accent-glow) 0%, transparent 70%);
  opacity: 0;
  transition: opacity var(--transition);
}

.upload-zone:hover,
.upload-zone.drag-over {
  border-color: var(--accent);
  background: rgba(59, 130, 246, 0.06);
}

.upload-zone:hover::before,
.upload-zone.drag-over::before {
  opacity: 1;
}

.upload-zone.drag-over {
  transform: scale(1.01);
}

.upload-zone-icon {
  width: 48px;
  height: 48px;
  border-radius: 50%;
  background: rgba(59, 130, 246, 0.15);
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--accent);
  position: relative;
  z-index: 1;
  transition: background var(--transition), transform var(--transition);
}

.upload-zone:hover .upload-zone-icon {
  background: rgba(59, 130, 246, 0.25);
  transform: translateY(-2px);
}

.upload-zone-text {
  position: relative;
  z-index: 1;
}

.upload-zone-text strong {
  display: block;
  font-size: 0.9rem;
  font-weight: 600;
  color: var(--text-primary);
}

.upload-zone-text span {
  font-size: 0.75rem;
  color: var(--text-muted);
}

.upload-zone input[type="file"] {
  position: absolute;
  inset: 0;
  opacity: 0;
  cursor: pointer;
}

.upload-filename {
  font-size: 0.75rem;
  color: var(--success);
  display: flex;
  align-items: center;
  gap: 6px;
  position: relative;
  z-index: 1;
  font-weight: 500;
}

/* ── Form controls ─────────────────────────────────────────────── */
.form-group {
  display: flex;
  flex-direction: column;
  gap: 6px;
}

.form-label {
  font-size: 0.74rem;
  font-weight: 600;
  letter-spacing: 0.04em;
  text-transform: uppercase;
  color: var(--text-secondary);
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.form-label-value {
  font-size: 0.78rem;
  font-weight: 500;
  color: var(--accent-hover);
  text-transform: none;
  letter-spacing: 0;
}

select, input[type="number"] {
  width: 100%;
  padding: 9px 12px;
  background: rgba(255,255,255,0.05);
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  color: var(--text-primary);
  font-family: var(--font);
  font-size: 0.85rem;
  appearance: none;
  cursor: pointer;
  transition: border-color var(--transition), background var(--transition), box-shadow var(--transition);
  outline: none;
}

select {
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='12' height='12' viewBox='0 0 12 12'%3E%3Cpath fill='%239ba3b8' d='M6 8L1 3h10z'/%3E%3C/svg%3E");
  background-repeat: no-repeat;
  background-position: right 10px center;
  padding-right: 30px;
}

select:hover, input[type="number"]:hover {
  border-color: rgba(255,255,255,0.2);
  background: rgba(255,255,255,0.07);
}

select:focus, input[type="number"]:focus {
  border-color: var(--border-focus);
  box-shadow: 0 0 0 3px rgba(99, 179, 237, 0.12);
}

/* Custom size row */
.size-row {
  display: grid;
  grid-template-columns: 1fr auto 1fr;
  align-items: center;
  gap: 8px;
}

.size-row-sep {
  color: var(--text-muted);
  font-size: 0.85rem;
  text-align: center;
}

/* Slider */
input[type="range"] {
  -webkit-appearance: none;
  appearance: none;
  width: 100%;
  height: 4px;
  background: rgba(255,255,255,0.1);
  border-radius: 2px;
  outline: none;
  cursor: pointer;
  transition: background var(--transition);
}

input[type="range"]::-webkit-slider-thumb {
  -webkit-appearance: none;
  width: 16px;
  height: 16px;
  border-radius: 50%;
  background: var(--accent);
  box-shadow: 0 0 0 3px var(--accent-glow);
  cursor: pointer;
  transition: transform var(--transition), box-shadow var(--transition), background var(--transition);
}

input[type="range"]:hover::-webkit-slider-thumb {
  transform: scale(1.2);
  background: var(--accent-hover);
  box-shadow: 0 0 0 5px var(--accent-glow);
}

/* Segmented controls */
.seg-group {
  display: flex;
  gap: 4px;
  background: rgba(0,0,0,0.3);
  padding: 3px;
  border-radius: var(--radius-sm);
  border: 1px solid var(--border);
}

.seg-btn {
  flex: 1;
  padding: 6px 4px;
  background: transparent;
  border: none;
  border-radius: 4px;
  font-family: var(--font);
  font-size: 0.72rem;
  font-weight: 500;
  color: var(--text-muted);
  cursor: pointer;
  transition: background var(--transition), color var(--transition);
  white-space: nowrap;
}

.seg-btn:hover { color: var(--text-secondary); background: var(--bg-hover); }

.seg-btn.active {
  background: var(--accent);
  color: #fff;
  box-shadow: 0 1px 6px var(--accent-glow);
}

/* ── Buttons ───────────────────────────────────────────────────── */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 10px 18px;
  border-radius: var(--radius-sm);
  font-family: var(--font);
  font-size: 0.85rem;
  font-weight: 600;
  cursor: pointer;
  border: none;
  transition: background var(--transition), transform var(--transition), box-shadow var(--transition), opacity var(--transition);
  outline: none;
  white-space: nowrap;
}

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

.btn-primary {
  background: var(--accent);
  color: #fff;
  box-shadow: 0 2px 12px var(--accent-glow);
}

.btn-primary:hover:not(:disabled) {
  background: var(--accent-hover);
  box-shadow: 0 4px 20px rgba(59,130,246,0.5);
  transform: translateY(-1px);
}

.btn-secondary {
  background: rgba(255,255,255,0.07);
  color: var(--text-primary);
  border: 1px solid var(--border);
}

.btn-secondary:hover:not(:disabled) {
  background: rgba(255,255,255,0.12);
  border-color: rgba(255,255,255,0.2);
}

.btn-success {
  background: var(--success);
  color: #fff;
  box-shadow: 0 2px 12px rgba(16,185,129,0.35);
}

.btn-success:hover:not(:disabled) {
  background: #34d399;
  transform: translateY(-1px);
  box-shadow: 0 4px 20px rgba(16,185,129,0.5);
}

.btn:disabled {
  opacity: 0.38;
  cursor: not-allowed;
  transform: none !important;
}

.btn-row {
  display: flex;
  gap: 10px;
}

.btn-row .btn { flex: 1; }

/* ── Error / Warning banner ────────────────────────────────────── */
.banner {
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 10px 14px;
  border-radius: var(--radius-sm);
  font-size: 0.8rem;
  font-weight: 500;
  animation: slideDown 0.2s ease;
}

.banner-error   { background: rgba(239,68,68,0.12);  border: 1px solid rgba(239,68,68,0.3);  color: #fca5a5; }
.banner-warning { background: rgba(245,158,11,0.12); border: 1px solid rgba(245,158,11,0.3); color: #fcd34d; }
.banner-info    { background: rgba(59,130,246,0.12); border: 1px solid rgba(59,130,246,0.3); color: #93c5fd; }

.banner-close {
  margin-left: auto;
  background: none;
  border: none;
  color: inherit;
  cursor: pointer;
  opacity: 0.6;
  font-size: 1rem;
  line-height: 1;
  padding: 0 2px;
}

.banner-close:hover { opacity: 1; }

/* ── Preview panel ─────────────────────────────────────────────── */
.preview-tabs {
  display: flex;
  gap: 2px;
  padding: 4px;
  background: rgba(0,0,0,0.25);
  border-radius: var(--radius-sm);
  width: fit-content;
}

.preview-tab {
  padding: 6px 16px;
  border-radius: 4px;
  font-size: 0.78rem;
  font-weight: 500;
  cursor: pointer;
  background: none;
  border: none;
  font-family: var(--font);
  color: var(--text-muted);
  transition: background var(--transition), color var(--transition);
}

.preview-tab:hover { color: var(--text-secondary); background: var(--bg-hover); }

.preview-tab.active {
  background: var(--accent);
  color: #fff;
}

.preview-canvas-wrap {
  position: relative;
  border-radius: var(--radius-lg);
  overflow: hidden;
  border: 1px solid var(--border);
  background: repeating-conic-gradient(rgba(255,255,255,0.04) 0% 25%, transparent 0% 50%) 0 0 / 20px 20px;
  min-height: 200px;
  display: flex;
  align-items: center;
  justify-content: center;
}

.preview-canvas-wrap canvas,
.preview-canvas-wrap img {
  max-width: 100%;
  max-height: 520px;
  display: block;
  border-radius: var(--radius-sm);
}

.preview-repeat-wrap {
  border-radius: var(--radius-lg);
  overflow: hidden;
  border: 1px solid var(--border);
  min-height: 200px;
}

.preview-empty {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 10px;
  padding: 60px 20px;
  color: var(--text-muted);
}

.preview-empty svg { opacity: 0.3; }

.preview-empty-text {
  font-size: 0.85rem;
  text-align: center;
}

/* Processing spinner */
.spinner-overlay {
  position: absolute;
  inset: 0;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  background: rgba(11,14,26,0.75);
  backdrop-filter: blur(4px);
  gap: 12px;
  border-radius: inherit;
  z-index: 10;
}

.spinner {
  width: 36px;
  height: 36px;
  border: 3px solid rgba(255,255,255,0.1);
  border-top-color: var(--accent);
  border-radius: 50%;
  animation: spin 0.7s linear infinite;
}

.spinner-text {
  font-size: 0.8rem;
  color: var(--text-secondary);
}

/* Preview stats bar */
.preview-stats {
  display: flex;
  align-items: center;
  gap: 20px;
  padding: 10px 16px;
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  font-size: 0.75rem;
  color: var(--text-muted);
}

.preview-stat strong {
  color: var(--text-secondary);
  font-weight: 600;
}

/* ── Divider ───────────────────────────────────────────────────── */
.divider {
  height: 1px;
  background: var(--border);
  margin: 4px 0;
}

/* ── Animations ────────────────────────────────────────────────── */
@keyframes spin {
  to { transform: rotate(360deg); }
}

@keyframes slideDown {
  from { opacity: 0; transform: translateY(-6px); }
  to   { opacity: 1; transform: translateY(0); }
}

@keyframes fadeIn {
  from { opacity: 0; }
  to   { opacity: 1; }
}

.fade-in { animation: fadeIn 0.3s ease; }

/* ── Responsive ────────────────────────────────────────────────── */
@media (max-width: 860px) {
  .app-body {
    grid-template-columns: 1fr;
  }
  .sidebar {
    border-right: none;
    border-bottom: 1px solid var(--border);
  }
}