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

:root {
  --color-bg: #1a1a2e;
  --color-surface: #16213e;
  --color-panel: #0f3460;
  --color-accent: #e94560;
  --color-accent2: #533483;
  --color-text: #eaeaea;
  --color-text-muted: #aaa;
  --color-border: #2a3a5e;
  --color-hover: #1a2a4e;
  --radius: 6px;
  --shadow: 0 2px 8px rgba(0,0,0,0.4);
}

html {
  scroll-behavior: smooth;
}

body {
  font-family: -apple-system, BlinkMacSystemFont, "Noto Sans JP", "Segoe UI", sans-serif;
  font-size: 15px;
  line-height: 1.6;
  color: var(--color-text);
  background: var(--color-bg);
  min-height: 100vh;
}

/* ============ HEADER ============ */
header {
  background: linear-gradient(135deg, #0f3460 0%, #533483 100%);
  padding: 1.25rem 1rem;
  text-align: center;
  box-shadow: var(--shadow);
}

.header-inner {
  max-width: 1100px;
  margin: 0 auto;
}

header h1 {
  font-size: 1.1rem;
  font-weight: 700;
  color: #fff;
  line-height: 1.4;
}

.subtitle {
  font-size: 0.8rem;
  color: rgba(255,255,255,0.75);
  margin-top: 0.25rem;
}

/* ============ MAIN ============ */
main {
  max-width: 1100px;
  margin: 0 auto;
  padding: 0.75rem;
}

/* ============ AD UNITS ============ */
.ad-unit {
  margin: 1.25rem 0;
}

/* ============ EDITOR SECTION ============ */
.editor-section {
  background: var(--color-surface);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  overflow: hidden;
  position: relative;
}

/* ---- TOOLBAR ROW ---- */
.toolbar-row {
  display: flex;
  align-items: center;
  flex-wrap: wrap;
  gap: 0.5rem;
  padding: 0.5rem 0.75rem;
  background: var(--color-panel);
  border-bottom: 1px solid var(--color-border);
}

.toolbar-row.toolbar-bottom {
  border-top: 1px solid var(--color-border);
  border-bottom: none;
  flex-wrap: wrap;
}

.toolbar-group {
  display: flex;
  align-items: center;
  gap: 0.35rem;
  flex-wrap: wrap;
}

.toolbar-label {
  font-size: 0.8rem;
  color: var(--color-text-muted);
  white-space: nowrap;
}

.toolbar-row select {
  padding: 0.3rem 0.5rem;
  font-size: 0.85rem;
  background: var(--color-surface);
  color: var(--color-text);
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  cursor: pointer;
  min-height: 44px;
}

/* ---- ICON BUTTONS ---- */
.icon-btn {
  min-width: 44px;
  min-height: 44px;
  padding: 0.3rem 0.5rem;
  background: var(--color-surface);
  color: var(--color-text);
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  cursor: pointer;
  font-size: 1rem;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  transition: background 0.15s, border-color 0.15s;
}

.icon-btn:hover {
  background: var(--color-hover);
  border-color: #4a6aae;
}

.icon-btn--danger {
  border-color: #6b2a2a;
  color: #e06060;
}

.icon-btn--danger:hover {
  background: #3a1a1a;
  border-color: var(--color-accent);
}

/* ---- ACTION BUTTONS ---- */
.action-btn {
  min-height: 44px;
  padding: 0.35rem 0.9rem;
  background: var(--color-surface);
  color: var(--color-text);
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  cursor: pointer;
  font-size: 0.85rem;
  font-weight: 600;
  white-space: nowrap;
  transition: background 0.15s;
}

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

.action-btn--primary {
  background: var(--color-accent);
  border-color: var(--color-accent);
  color: #fff;
}

.action-btn--primary:hover {
  background: #c73350;
}

/* ============ EDITOR BODY ============ */
.editor-body {
  display: flex;
  flex-direction: column;
  min-height: 420px;
}

/* ============ SIDEBAR ============ */
.sidebar {
  display: flex;
  flex-direction: row;
  flex-wrap: wrap;
  gap: 0.5rem;
  padding: 0.5rem;
  background: var(--color-bg);
  border-bottom: 1px solid var(--color-border);
}

.panel {
  background: var(--color-surface);
  border-radius: var(--radius);
  padding: 0.5rem 0.6rem;
  min-width: 100px;
  flex: 1 1 auto;
}

.panel-title {
  font-size: 0.7rem;
  font-weight: 700;
  color: var(--color-text-muted);
  text-transform: uppercase;
  letter-spacing: 0.05em;
  margin-bottom: 0.35rem;
}

/* ---- TOOL BUTTONS ---- */
.tool-buttons {
  display: flex;
  gap: 0.3rem;
  flex-wrap: wrap;
}

.tool-btn {
  width: 44px;
  height: 44px;
  background: var(--color-bg);
  color: var(--color-text);
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  cursor: pointer;
  font-size: 1.1rem;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: background 0.15s, border-color 0.15s;
}

.tool-btn:hover {
  background: var(--color-hover);
  border-color: #4a6aae;
}

.tool-btn.active {
  background: var(--color-accent2);
  border-color: #7a50c0;
  color: #fff;
}

/* ---- COLOR CURRENT ---- */
.color-current-wrap {
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.color-current {
  width: 44px;
  height: 44px;
  border-radius: var(--radius);
  border: 2px solid var(--color-border);
  cursor: pointer;
  background: #000;
  flex-shrink: 0;
}

input[type="color"] {
  width: 44px;
  height: 44px;
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  background: var(--color-surface);
  cursor: pointer;
  padding: 2px;
}

/* ---- PALETTE TABS ---- */
.palette-tabs {
  display: flex;
  gap: 0.25rem;
  margin-bottom: 0.4rem;
}

.palette-tab {
  flex: 1;
  padding: 0.25rem 0;
  font-size: 0.75rem;
  font-weight: 700;
  background: var(--color-bg);
  color: var(--color-text-muted);
  border: 1px solid var(--color-border);
  border-radius: 4px;
  cursor: pointer;
  min-height: 44px;
  transition: background 0.15s;
}

.palette-tab.active {
  background: var(--color-panel);
  color: #fff;
  border-color: #4a6aae;
}

/* ---- PALETTE GRID ---- */
.palette-grid {
  display: grid;
  grid-template-columns: repeat(8, 1fr);
  gap: 2px;
  margin-bottom: 0.4rem;
  min-height: 50px;
}

.palette-swatch {
  aspect-ratio: 1;
  border-radius: 3px;
  border: 1px solid transparent;
  cursor: pointer;
  transition: transform 0.1s, border-color 0.1s;
  min-height: 20px;
}

.palette-swatch:hover {
  transform: scale(1.2);
  border-color: #fff;
  z-index: 1;
  position: relative;
}

.palette-swatch.selected {
  border-color: #fff;
  box-shadow: 0 0 0 1px #fff;
  transform: scale(1.15);
}

/* ---- SMALL BUTTON ---- */
.small-btn {
  font-size: 0.78rem;
  padding: 0.3rem 0.6rem;
  min-height: 44px;
  background: var(--color-bg);
  color: var(--color-text);
  border: 1px solid var(--color-border);
  border-radius: 4px;
  cursor: pointer;
  width: 100%;
  transition: background 0.15s;
}

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

/* ---- LAYER LIST ---- */
.layer-list {
  display: flex;
  flex-direction: column;
  gap: 0.3rem;
  margin-bottom: 0.4rem;
  max-height: 120px;
  overflow-y: auto;
}

.layer-item {
  display: flex;
  align-items: center;
  gap: 0.3rem;
  padding: 0.3rem 0.4rem;
  background: var(--color-bg);
  border-radius: 4px;
  border: 1px solid transparent;
  cursor: pointer;
  min-height: 44px;
  transition: background 0.15s;
}

.layer-item.active {
  border-color: var(--color-accent2);
  background: var(--color-hover);
}

.layer-item:hover {
  background: var(--color-hover);
}

.layer-vis-btn {
  width: 24px;
  height: 24px;
  min-width: 44px;
  min-height: 44px;
  background: transparent;
  border: none;
  cursor: pointer;
  font-size: 0.85rem;
  color: var(--color-text-muted);
  padding: 0;
  display: flex;
  align-items: center;
  justify-content: center;
}

.layer-name {
  flex: 1;
  font-size: 0.82rem;
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}

.layer-opacity {
  width: 50px;
  padding: 2px 4px;
  font-size: 0.75rem;
  background: var(--color-surface);
  color: var(--color-text);
  border: 1px solid var(--color-border);
  border-radius: 3px;
  text-align: center;
}

.layer-del-btn {
  width: 24px;
  height: 24px;
  min-width: 44px;
  min-height: 44px;
  background: transparent;
  border: none;
  cursor: pointer;
  font-size: 0.85rem;
  color: #e06060;
  padding: 0;
  display: flex;
  align-items: center;
  justify-content: center;
}

/* ============ CANVAS WRAP ============ */
.canvas-wrap {
  flex: 1;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 0.75rem;
  background: #111;
  overflow: auto;
  position: relative;
  min-height: 320px;
}

/* Checkerboard background for transparency */
.canvas-wrap::before {
  content: '';
  position: absolute;
  inset: 0;
  background-image:
    linear-gradient(45deg, #222 25%, transparent 25%),
    linear-gradient(-45deg, #222 25%, transparent 25%),
    linear-gradient(45deg, transparent 75%, #222 75%),
    linear-gradient(-45deg, transparent 75%, #222 75%);
  background-size: 16px 16px;
  background-position: 0 0, 0 8px, 8px -8px, -8px 0;
  pointer-events: none;
}

#pixel-canvas,
#grid-canvas {
  image-rendering: pixelated;
  image-rendering: crisp-edges;
  cursor: crosshair;
  border: 1px solid #333;
  position: absolute;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  touch-action: none;
}

#grid-canvas {
  pointer-events: none;
}

/* ============ FRAME LIST ============ */
.frames-group {
  flex: 1;
  min-width: 0;
  overflow: hidden;
}

.frame-list {
  display: flex;
  gap: 0.3rem;
  overflow-x: auto;
  padding-bottom: 2px;
  flex: 1;
}

.frame-thumb {
  flex-shrink: 0;
  width: 44px;
  height: 44px;
  background: var(--color-bg);
  border: 2px solid var(--color-border);
  border-radius: 4px;
  cursor: pointer;
  overflow: hidden;
  position: relative;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 0.7rem;
  color: var(--color-text-muted);
  transition: border-color 0.15s;
}

.frame-thumb.active {
  border-color: var(--color-accent);
}

.frame-thumb canvas {
  image-rendering: pixelated;
  max-width: 100%;
  max-height: 100%;
}

.frame-del-btn {
  position: absolute;
  top: 1px;
  right: 1px;
  width: 14px;
  height: 14px;
  background: rgba(0,0,0,0.6);
  border: none;
  border-radius: 50%;
  cursor: pointer;
  font-size: 0.55rem;
  color: #e06060;
  display: none;
  align-items: center;
  justify-content: center;
  padding: 0;
  line-height: 1;
}

.frame-thumb:hover .frame-del-btn {
  display: flex;
}

/* ============ PREVIEW MODAL ============ */
.modal {
  position: fixed;
  inset: 0;
  background: rgba(0,0,0,0.75);
  display: flex;
  align-items: center;
  justify-content: center;
  z-index: 100;
}

.modal[hidden] {
  display: none;
}

.modal-inner {
  background: var(--color-surface);
  border-radius: var(--radius);
  padding: 1rem;
  box-shadow: var(--shadow);
  max-width: 90vw;
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
}

.modal-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  font-weight: 700;
  font-size: 0.95rem;
}

.preview-canvas {
  image-rendering: pixelated;
  border: 1px solid var(--color-border);
  background: #111;
  max-width: 80vw;
  max-height: 50vh;
}

.preview-controls {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  font-size: 0.85rem;
}

.preview-controls label {
  display: flex;
  align-items: center;
  gap: 0.4rem;
}

.preview-controls input[type="range"] {
  width: 120px;
}

/* ============ HOWTO SECTION ============ */
.howto-section {
  background: var(--color-surface);
  border-radius: var(--radius);
  padding: 1.25rem 1rem;
  margin-top: 0;
  box-shadow: var(--shadow);
}

.howto-section h2 {
  font-size: 1rem;
  font-weight: 700;
  color: #9ab8f0;
  margin-bottom: 0.6rem;
  margin-top: 1.25rem;
  padding-bottom: 0.3rem;
  border-bottom: 1px solid var(--color-border);
}

.howto-section h2:first-child {
  margin-top: 0;
}

.howto-section ol {
  padding-left: 1.25rem;
  color: var(--color-text-muted);
  font-size: 0.9rem;
}

.howto-section li {
  margin-bottom: 0.5rem;
  line-height: 1.6;
}

.howto-section p {
  font-size: 0.9rem;
  color: var(--color-text-muted);
  line-height: 1.7;
}

.shortcut-table {
  width: 100%;
  border-collapse: collapse;
  font-size: 0.85rem;
  margin-top: 0.25rem;
}

.shortcut-table th,
.shortcut-table td {
  padding: 0.4rem 0.6rem;
  border: 1px solid var(--color-border);
  text-align: left;
  color: var(--color-text-muted);
}

.shortcut-table th {
  background: var(--color-panel);
  color: var(--color-text);
  font-weight: 600;
}

/* ============ FOOTER ============ */
footer {
  text-align: center;
  padding: 1.5rem 1rem;
  font-size: 0.82rem;
  color: var(--color-text-muted);
}

footer a {
  color: #7a9fd4;
  text-decoration: none;
}

footer a:hover {
  text-decoration: underline;
}

footer p + p {
  margin-top: 0.3rem;
}

/* ============ DESKTOP LAYOUT ============ */
@media (min-width: 640px) {
  header h1 {
    font-size: 1.35rem;
  }

  main {
    padding: 1rem 1.5rem;
  }
}

@media (min-width: 800px) {
  .editor-body {
    flex-direction: row;
  }

  .sidebar {
    flex-direction: column;
    flex-wrap: nowrap;
    width: 180px;
    min-width: 180px;
    border-bottom: none;
    border-right: 1px solid var(--color-border);
    overflow-y: auto;
    max-height: 560px;
  }

  .panel {
    flex: 0 0 auto;
  }

  .palette-grid {
    grid-template-columns: repeat(4, 1fr);
  }

  .canvas-wrap {
    min-height: 420px;
  }
}

@media (min-width: 1000px) {
  .sidebar {
    width: 200px;
    min-width: 200px;
  }

  .palette-grid {
    grid-template-columns: repeat(4, 1fr);
  }
}