/* ─── CSS Custom Properties ────────────────────────────────────────────────── */
:root {
  --bg: #f8f9fa;
  --surface: #ffffff;
  --surface-2: #f0f2f5;
  --border: #dde1e7;
  --text: #1a1d23;
  --text-2: #5a6074;
  --accent: #5c6bc0;
  --accent-hover: #3f51b5;
  --accent-text: #ffffff;
  --shadow: 0 2px 12px rgba(0, 0, 0, 0.08);
  --shadow-md: 0 4px 20px rgba(0, 0, 0, 0.12);
  --radius: 12px;
  --radius-sm: 8px;
  --transition: 0.2s ease;
}

[data-theme="dark"] {
  --bg: #12141c;
  --surface: #1e2030;
  --surface-2: #262840;
  --border: #353850;
  --text: #e8eaf6;
  --text-2: #9096b8;
  --accent: #7986cb;
  --accent-hover: #9fa8da;
  --accent-text: #12141c;
  --shadow: 0 2px 12px rgba(0, 0, 0, 0.3);
  --shadow-md: 0 4px 20px rgba(0, 0, 0, 0.4);
}

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

html {
  font-size: 16px;
  scroll-behavior: smooth;
}

body {
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'Noto Sans JP', sans-serif;
  background: var(--bg);
  color: var(--text);
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  line-height: 1.6;
  transition: background var(--transition), color var(--transition);
}

/* ─── Header ─────────────────────────────────────────────────────────────────── */
.app-header {
  background: var(--surface);
  border-bottom: 1px solid var(--border);
  position: sticky;
  top: 0;
  z-index: 100;
  box-shadow: var(--shadow);
}

.header-inner {
  max-width: 800px;
  margin: 0 auto;
  padding: 14px 20px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
}

.header-title h1 {
  font-size: 1.25rem;
  font-weight: 700;
  color: var(--text);
  line-height: 1.2;
}

.subtitle {
  font-size: 0.8rem;
  color: var(--text-2);
  margin-top: 2px;
}

.header-controls {
  display: flex;
  align-items: center;
  gap: 8px;
}

.icon-btn {
  background: var(--surface-2);
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  padding: 7px;
  cursor: pointer;
  color: var(--text);
  display: flex;
  align-items: center;
  justify-content: center;
  transition: background var(--transition);
}

.icon-btn:hover {
  background: var(--border);
}

/* Show sun in dark mode, moon in light mode */
[data-theme="light"] .icon-moon { display: none; }
[data-theme="dark"] .icon-sun { display: none; }

.lang-btn {
  background: var(--surface-2);
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  padding: 6px 12px;
  cursor: pointer;
  color: var(--text);
  font-size: 0.82rem;
  font-weight: 600;
  transition: background var(--transition);
}

.lang-btn:hover {
  background: var(--border);
}

/* ─── Main ───────────────────────────────────────────────────────────────────── */
.app-main {
  max-width: 800px;
  margin: 0 auto;
  padding: 24px 20px;
  flex: 1;
  display: flex;
  flex-direction: column;
  gap: 20px;
  width: 100%;
}

.card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 24px;
  box-shadow: var(--shadow);
}

/* ─── Upload / Dropzone ──────────────────────────────────────────────────────── */
.upload-section {
  display: flex;
  flex-direction: column;
  gap: 16px;
}

.dropzone {
  border: 2px dashed var(--border);
  border-radius: var(--radius-sm);
  min-height: 220px;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  position: relative;
  overflow: hidden;
  transition: border-color var(--transition), background var(--transition);
}

.dropzone:hover,
.dropzone:focus-visible {
  border-color: var(--accent);
  background: var(--surface-2);
  outline: none;
}

.dropzone.drag-over {
  border-color: var(--accent);
  background: color-mix(in srgb, var(--accent) 8%, var(--surface));
}

.dropzone-placeholder {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 12px;
  padding: 24px;
  text-align: center;
  pointer-events: none;
}

.drop-icon {
  color: var(--text-2);
  opacity: 0.6;
}

#dropzoneText {
  color: var(--text);
  font-size: 0.95rem;
  font-weight: 500;
}

.dropzone-hint {
  color: var(--text-2);
  font-size: 0.8rem;
}

#imagePreview {
  max-width: 100%;
  max-height: 320px;
  object-fit: contain;
  border-radius: var(--radius-sm);
  display: block;
}

.dropzone.has-image .dropzone-placeholder {
  display: none;
}

.upload-actions {
  display: flex;
  justify-content: center;
}

/* ─── Controls ───────────────────────────────────────────────────────────────── */
.controls-section {
  display: flex;
  flex-direction: column;
  gap: 16px;
}

.control-row {
  display: flex;
  align-items: center;
  gap: 16px;
  flex-wrap: wrap;
}

.control-label {
  font-size: 0.9rem;
  font-weight: 600;
  color: var(--text-2);
  min-width: 100px;
}

.slider-row {
  display: flex;
  align-items: center;
  gap: 10px;
  flex: 1;
}

.k-slider {
  flex: 1;
  accent-color: var(--accent);
  height: 4px;
  cursor: pointer;
}

.slider-min, .slider-max {
  font-size: 0.8rem;
  color: var(--text-2);
  min-width: 16px;
  text-align: center;
}

.k-badge {
  background: var(--accent);
  color: var(--accent-text);
  border-radius: 6px;
  padding: 2px 10px;
  font-size: 0.85rem;
  font-weight: 700;
  min-width: 32px;
  text-align: center;
}

.sort-select {
  background: var(--surface-2);
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  padding: 7px 12px;
  color: var(--text);
  font-size: 0.88rem;
  cursor: pointer;
  transition: border-color var(--transition);
}

.sort-select:focus {
  outline: none;
  border-color: var(--accent);
}

/* ─── Buttons ────────────────────────────────────────────────────────────────── */
.primary-btn {
  background: var(--accent);
  color: var(--accent-text);
  border: none;
  border-radius: var(--radius-sm);
  padding: 12px 28px;
  font-size: 0.95rem;
  font-weight: 600;
  cursor: pointer;
  width: 100%;
  transition: background var(--transition), transform var(--transition);
}

.primary-btn:hover:not(:disabled) {
  background: var(--accent-hover);
}

.primary-btn:active:not(:disabled) {
  transform: scale(0.98);
}

.primary-btn:disabled {
  opacity: 0.6;
  cursor: not-allowed;
}

.secondary-btn {
  background: var(--surface-2);
  color: var(--text);
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  padding: 9px 20px;
  font-size: 0.88rem;
  font-weight: 500;
  cursor: pointer;
  transition: background var(--transition);
}

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

/* ─── Palette ─────────────────────────────────────────────────────────────────── */
.palette-section {
  display: flex;
  flex-direction: column;
  gap: 20px;
}

.palette-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 12px;
}

.palette-header h2 {
  font-size: 1rem;
  font-weight: 700;
}

.format-toggle {
  display: flex;
  gap: 4px;
  background: var(--surface-2);
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  padding: 3px;
}

.format-btn {
  background: transparent;
  border: none;
  border-radius: 6px;
  padding: 5px 14px;
  font-size: 0.82rem;
  font-weight: 600;
  color: var(--text-2);
  cursor: pointer;
  transition: background var(--transition), color var(--transition);
}

.format-btn.active {
  background: var(--accent);
  color: var(--accent-text);
}

.format-btn:hover:not(.active) {
  background: var(--border);
  color: var(--text);
}

/* ─── Swatches ────────────────────────────────────────────────────────────────── */
.swatches-container {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(140px, 1fr));
  gap: 14px;
}

.swatch {
  border-radius: var(--radius-sm);
  overflow: hidden;
  border: 1px solid var(--border);
  box-shadow: var(--shadow);
  transition: transform var(--transition), box-shadow var(--transition);
}

.swatch:hover {
  transform: translateY(-2px);
  box-shadow: var(--shadow-md);
}

.swatch-color {
  height: 96px;
  cursor: pointer;
  transition: filter var(--transition);
}

.swatch-color:hover {
  filter: brightness(0.92);
}

.swatch-label {
  background: var(--surface);
  padding: 8px 10px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 6px;
}

.swatch-value {
  font-size: 0.78rem;
  font-family: 'SF Mono', 'Consolas', 'Fira Code', monospace;
  color: var(--text);
  word-break: break-all;
}

.copy-btn {
  background: transparent;
  border: none;
  cursor: pointer;
  color: var(--text-2);
  padding: 2px;
  border-radius: 4px;
  display: flex;
  align-items: center;
  flex-shrink: 0;
  transition: color var(--transition);
}

.copy-btn:hover {
  color: var(--accent);
}

/* ─── No palette message ─────────────────────────────────────────────────────── */
.no-palette-msg {
  color: var(--text-2);
  font-size: 0.88rem;
  text-align: center;
  padding: 8px 0;
}

/* ─── Export ──────────────────────────────────────────────────────────────────── */
.export-row {
  display: flex;
  gap: 8px;
  flex-wrap: wrap;
}

.export-btn {
  background: var(--surface-2);
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  padding: 8px 16px;
  font-size: 0.85rem;
  font-weight: 600;
  color: var(--text);
  cursor: pointer;
  transition: background var(--transition), border-color var(--transition);
  flex: 1;
  min-width: 80px;
}

.export-btn:hover {
  background: var(--border);
  border-color: var(--accent);
  color: var(--accent);
}

/* ─── Toast ───────────────────────────────────────────────────────────────────── */
.toast {
  position: fixed;
  bottom: 32px;
  left: 50%;
  transform: translateX(-50%) translateY(20px);
  background: var(--text);
  color: var(--surface);
  padding: 10px 22px;
  border-radius: 24px;
  font-size: 0.88rem;
  font-weight: 600;
  pointer-events: none;
  opacity: 0;
  transition: opacity 0.25s ease, transform 0.25s ease;
  z-index: 1000;
  white-space: nowrap;
}

.toast.show {
  opacity: 1;
  transform: translateX(-50%) translateY(0);
}

/* ─── Footer ──────────────────────────────────────────────────────────────────── */
.app-footer {
  text-align: center;
  padding: 20px;
  color: var(--text-2);
  font-size: 0.8rem;
  border-top: 1px solid var(--border);
}

/* ─── Responsive ──────────────────────────────────────────────────────────────── */
@media (max-width: 480px) {
  .header-title h1 { font-size: 1.1rem; }
  .subtitle { display: none; }
  .app-main { padding: 16px 12px; gap: 14px; }
  .card { padding: 16px; }
  .swatches-container {
    grid-template-columns: repeat(auto-fill, minmax(120px, 1fr));
    gap: 10px;
  }
  .control-row { flex-direction: column; align-items: flex-start; }
  .export-row { flex-direction: column; }
  .export-btn { flex: unset; width: 100%; }
}