:root {
  --paper: #f4ecdb;
  --paper-deep: #ebe2c9;
  --ink: #2a2418;
  --ink-mid: #6c5f48;
  --line: #c0b294;
  --line-soft: #d6cab0;
  --serif: "Cormorant Garamond", Georgia, serif;
  --sans: "Inter", -apple-system, system-ui, sans-serif;
  --rail-w: 90px;
  --thumb-w: 240px;
  --top-h: 56px;
}

* { box-sizing: border-box; }
html, body { height: 100%; }
body {
  margin: 0;
  font-family: var(--sans);
  color: var(--ink);
  background: var(--paper);
  overflow: hidden;
}

button { font: inherit; color: inherit; cursor: pointer; }

/* topbar */
.topbar {
  height: var(--top-h);
  display: grid;
  grid-template-columns: 1fr auto 1fr;
  align-items: center;
  padding: 0 24px;
  border-bottom: 1px solid var(--line-soft);
  background: var(--paper);
}
.brand { font-family: var(--serif); font-size: 18px; letter-spacing: 0.01em; }
.brand .dim { color: var(--ink-mid); font-style: italic; }
.sources { display: flex; align-items: center; gap: 8px; justify-content: center; }
.src-tab {
  background: none; border: 0; padding: 4px 2px;
  font-family: var(--serif); font-size: 15px; color: var(--ink-mid);
  letter-spacing: 0.02em;
}
.src-tab.active { color: var(--ink); border-bottom: 1px solid var(--ink); }
.src-tab:disabled { color: #b8ad96; cursor: not-allowed; }
.dot { color: var(--line); font-size: 12px; }
.actions { display: flex; gap: 12px; justify-content: flex-end; }
.ghost {
  background: none; border: 1px solid var(--line); padding: 6px 12px;
  font-size: 11px; letter-spacing: 0.08em; text-transform: uppercase;
  color: var(--ink-mid);
}
.ghost:hover:not(:disabled) { border-color: var(--ink); color: var(--ink); }
.ghost:disabled { opacity: 0.4; cursor: not-allowed; }

/* layout */
.layout {
  display: grid;
  grid-template-columns: var(--rail-w) 1fr var(--thumb-w);
  height: calc(100vh - var(--top-h));
}

/* tool rail */
.rail.tools {
  border-right: 1px solid var(--line-soft);
  padding: 20px 8px;
  display: flex; flex-direction: column; gap: 14px;
  background: var(--paper);
}
.tool {
  background: none; border: 0; padding: 8px 4px;
  display: flex; flex-direction: column; align-items: center; gap: 4px;
  font-family: var(--serif); font-size: 13px; color: var(--ink);
  border-bottom: 1px solid var(--line-soft);
  width: 100%;
}
.tool svg { color: var(--ink); margin-bottom: 2px; }
.tool .tool-num { color: var(--ink-mid); font-style: italic; margin-right: 2px; }
.tool:hover:not(:disabled) { background: var(--paper-deep); }
.tool.active { background: var(--paper-deep); color: var(--ink); }
.tool.active::after {
  content: ''; position: absolute; left: -1px; width: 2px; height: 100%; background: var(--ink);
}
.tool { position: relative; }
.tool:disabled, .tool.disabled {
  color: #b8ad96; cursor: not-allowed; opacity: 0.55;
}
.tool-hint {
  font-family: var(--serif); font-style: italic; font-size: 12px;
  color: var(--ink-mid); text-align: center; margin-top: auto; padding-top: 12px;
  line-height: 1.4;
}

/* surface */
.surface-wrap {
  position: relative; overflow: hidden;
  background: var(--paper);
}
.surface { width: 100%; height: 100%; display: block; touch-action: none; }
.grid-label {
  position: absolute; bottom: 14px; left: 18px;
  font-family: var(--serif); font-style: italic; font-size: 11px;
  color: var(--ink-mid); letter-spacing: 0.04em;
}

.piece-bar {
  position: absolute; bottom: 14px; left: 50%; transform: translateX(-50%);
  background: var(--paper); border: 1px solid var(--line);
  padding: 8px 16px; display: flex; align-items: center; gap: 16px;
  box-shadow: 0 2px 8px rgba(42,36,24,0.08);
}
.opacity-control { display: flex; align-items: center; gap: 10px;
  font-family: var(--serif); font-style: italic; font-size: 13px; color: var(--ink-mid); }
.opacity-control input[type="range"] {
  -webkit-appearance: none; appearance: none; width: 140px; height: 2px;
  background: var(--line); outline: none;
}
.opacity-control input[type="range"]::-webkit-slider-thumb {
  -webkit-appearance: none; appearance: none; width: 12px; height: 12px;
  background: var(--ink); border-radius: 50%; cursor: pointer;
}
.opacity-control input[type="range"]::-moz-range-thumb {
  width: 12px; height: 12px; background: var(--ink); border: 0; border-radius: 50%; cursor: pointer;
}
.opacity-control .readout {
  font-style: normal; font-family: var(--sans); font-size: 11px;
  color: var(--ink); min-width: 36px; text-align: right;
  letter-spacing: 0.04em;
}
.bar-divider { width: 1px; height: 18px; background: var(--line-soft); }
.bar-link {
  background: none; border: 0; padding: 4px 6px;
  font-family: var(--serif); font-style: italic; font-size: 12px;
  color: var(--ink-mid); cursor: pointer;
}
.bar-link:hover { color: var(--ink); }
.bar-link.active {
  color: var(--ink);
  text-decoration: underline;
  text-underline-offset: 3px;
}
.edge-ribbon { fill: rgba(42,36,24,0.05); cursor: pointer; }
.edge-ribbon:hover { fill: rgba(42,36,24,0.18); }
.edge-ribbon.active { fill: rgba(42,36,24,0.10); stroke: var(--ink); stroke-width: 1; stroke-dasharray: 3 2; }

/* selection overlay */
.sel-rect { fill: none; stroke: var(--ink); stroke-width: 1; stroke-dasharray: 4 3; pointer-events: none; }
.sel-handle { fill: var(--paper); stroke: var(--ink); stroke-width: 1; cursor: pointer; }
.sel-handle.move { cursor: grab; }
.sel-handle.rotate { cursor: grab; }
.crop-rect { fill: rgba(42,36,24,0.06); stroke: var(--ink); stroke-width: 1; stroke-dasharray: 5 3; pointer-events: none; }

.piece { cursor: grab; }
.piece.dragging { cursor: grabbing; }
.piece-shadow {
  filter: drop-shadow(0 2px 4px rgba(0,0,0,0.18));
}

/* thumbnail rail */
.rail.thumbs {
  border-left: 1px solid var(--line-soft);
  padding: 16px 16px 12px; overflow-y: auto;
  background: var(--paper);
  display: flex; flex-direction: column;
}
.thumb-head {
  font-family: var(--serif); font-size: 13px; color: var(--ink-mid);
  letter-spacing: 0.04em; margin-bottom: 12px;
}
.thumb-head span { color: var(--ink); font-style: italic; }
.thumb-grid {
  display: grid; grid-template-columns: 1fr 1fr; gap: 8px;
  flex: 1; align-content: start;
}
.thumb-loading { grid-column: 1 / -1; color: var(--ink-mid); font-style: italic; font-size: 12px; padding: 12px; }
.thumb {
  aspect-ratio: 1 / 1; overflow: hidden;
  border: 1px solid var(--line-soft);
  background: var(--paper-deep);
  cursor: pointer; transition: border-color 0.12s, transform 0.12s;
}
.thumb:hover { border-color: var(--ink); transform: scale(1.02); }
.thumb img { width: 100%; height: 100%; object-fit: cover; display: block; }
.thumb.placing { border-color: var(--ink); outline: 2px solid var(--ink); }
.more {
  background: none; border: 0; margin-top: 12px;
  font-family: var(--serif); font-style: italic; font-size: 13px;
  color: var(--ink-mid); text-align: left; padding: 4px 0;
}
.more:hover { color: var(--ink); }

/* layer panel */
.layer-panel {
  position: absolute; top: 14px; left: 14px;
  width: 200px; max-height: calc(100% - 100px);
  background: var(--paper); border: 1px solid var(--line);
  box-shadow: 0 2px 8px rgba(42,36,24,0.08);
  display: flex; flex-direction: column;
  z-index: 5;
}
.layer-head {
  display: flex; align-items: center; justify-content: space-between;
  padding: 8px 10px;
  font-family: var(--serif); font-style: italic; font-size: 13px;
  color: var(--ink-mid); letter-spacing: 0.04em;
  border-bottom: 1px solid var(--line-soft);
}
.layer-toggle {
  background: none; border: 0; padding: 0 4px;
  font-family: var(--sans); font-size: 16px; line-height: 1;
  color: var(--ink-mid); cursor: pointer;
}
.layer-toggle:hover { color: var(--ink); }
.layer-list {
  list-style: none; margin: 0; padding: 4px 0;
  overflow-y: auto; flex: 1; min-height: 0;
}
.layer-panel.collapsed {
  width: 118px;
  max-height: none;
}
.layer-panel.collapsed .layer-head {
  border-bottom: 0;
}
.layer-panel.collapsed .layer-list {
  display: none;
}
.layer-row {
  display: flex; align-items: center; gap: 8px;
  padding: 4px 10px; cursor: pointer;
  border-left: 2px solid transparent;
  user-select: none;
}
.layer-row:hover { background: var(--paper-deep); }
.layer-row.selected { background: var(--paper-deep); border-left-color: var(--ink); }
.layer-row.dragging { opacity: 0.4; }
.layer-row.drop-above { border-top: 1px solid var(--ink); }
.layer-row.drop-below { border-bottom: 1px solid var(--ink); }
.layer-thumb {
  width: 28px; height: 28px; flex-shrink: 0;
  background-size: cover; background-position: center;
  border: 1px solid var(--line-soft);
}
.layer-row.hidden .layer-thumb { opacity: 0.35; filter: grayscale(0.6); }
.layer-row.locked .layer-thumb { opacity: 0.65; }
.layer-row.locked .layer-meta { color: var(--line); }
.layer-meta {
  flex: 1; min-width: 0;
  font-family: var(--serif); font-style: italic; font-size: 12px;
  color: var(--ink-mid);
  overflow: hidden; text-overflow: ellipsis; white-space: nowrap;
}
.layer-row.selected .layer-meta { color: var(--ink); }
.layer-action {
  background: none; border: 0; padding: 2px 4px;
  font-size: 11px; color: var(--ink-mid); cursor: pointer;
  font-family: var(--sans);
}
.layer-action:hover { color: var(--ink); }
.layer-row.hidden .layer-eye,
.layer-row.locked .layer-lock { color: var(--line); }
/* help button — circular, sits in actions group */
.help-btn {
  width: 28px; height: 28px; padding: 0;
  border-radius: 50%;
  display: inline-flex; align-items: center; justify-content: center;
  font-family: var(--serif); font-style: italic; font-size: 14px;
  letter-spacing: 0; text-transform: none;
}

/* guide overlay */
.guide-overlay[hidden] {
  display: none !important;
}

.guide-overlay {
  position: fixed; inset: 0;
  background: rgba(42, 36, 24, 0.32);
  backdrop-filter: blur(2px); -webkit-backdrop-filter: blur(2px);
  display: flex; align-items: center; justify-content: center;
  z-index: 50;
  animation: guide-fade-in 0.25s ease-out;
}
@keyframes guide-fade-in { from { opacity: 0; } to { opacity: 1; } }
.guide-card {
  position: relative;
  background: var(--paper);
  border: 1px solid var(--line);
  box-shadow: 0 8px 32px rgba(42, 36, 24, 0.18);
  padding: 36px 44px 32px;
  max-width: 460px; width: calc(100vw - 48px);
  text-align: left;
}
.guide-close {
  position: absolute; top: 10px; right: 12px;
  background: none; border: 0; padding: 4px 8px;
  font-family: var(--sans); font-size: 14px;
  color: var(--ink-mid); cursor: pointer;
}
.guide-close:hover { color: var(--ink); }
.guide-title {
  margin: 0 0 4px;
  font-family: var(--serif); font-weight: 500;
  font-size: 28px; letter-spacing: 0.01em; color: var(--ink);
}
.guide-flow {
  margin: 0 0 22px;
  font-family: var(--serif); font-style: italic;
  font-size: 14px; color: var(--ink-mid);
  letter-spacing: 0.04em;
}
.guide-steps {
  list-style: none; padding: 0; margin: 0 0 22px;
  font-family: var(--sans); font-size: 13px; color: var(--ink);
  line-height: 1.7;
}
.guide-steps li {
  position: relative; padding-left: 18px;
}
.guide-steps li::before {
  content: '·'; position: absolute; left: 4px; top: -2px;
  font-size: 18px; color: var(--ink-mid);
}
.guide-steps em {
  font-style: italic; font-family: var(--serif); color: var(--ink);
}
.guide-shortcuts {
  margin: 0 0 24px;
  font-family: var(--serif); font-style: italic;
  font-size: 12px; color: var(--ink-mid);
  border-top: 1px solid var(--line-soft);
  padding-top: 14px;
}
.guide-start {
  background: var(--ink); color: var(--paper);
  border: 0; padding: 10px 28px;
  font-family: var(--serif); font-style: italic; font-size: 14px;
  cursor: pointer;
  letter-spacing: 0.02em;
}
.guide-start:hover { background: #1a160e; }
@media (max-width: 700px) {
  .guide-card { padding: 28px 24px 24px; max-width: 360px; }
  .guide-title { font-size: 22px; }
}

/* coarse-pointer (touch) — beefier hit targets, larger thumb sliders */
@media (pointer: coarse) {
  .opacity-control input[type="range"]::-webkit-slider-thumb { width: 18px; height: 18px; }
  .opacity-control input[type="range"]::-moz-range-thumb { width: 18px; height: 18px; }
  .layer-row { padding: 8px 10px; }
  .layer-thumb { width: 36px; height: 36px; }
  .layer-eye { padding: 6px 8px; font-size: 14px; }
  .src-tab { padding: 8px 6px; font-size: 16px; }
  .ghost { padding: 8px 14px; font-size: 12px; }
}

/* narrow viewport (phones, tablets) */
@media (max-width: 700px) {
  :root { --rail-w: 56px; --thumb-w: 140px; --top-h: 48px; }
  .topbar { padding: 0 8px; grid-template-columns: auto 1fr auto; gap: 8px; }
  .brand { font-size: 15px; }
  .brand .dim { display: none; }
  .sources { gap: 2px; min-width: 0; }
  .src-tab { font-size: 13px; padding: 4px 1px; }
  .dot { display: none; }
  .actions { gap: 4px; }
  .ghost { padding: 5px 6px; font-size: 9px; letter-spacing: 0; text-transform: lowercase; border-radius: 0; }
  .rail.tools { padding: 12px 4px; gap: 8px; }
  .tool { font-size: 11px; }
  .tool svg { width: 16px; height: 16px; }
  .tool-hint { font-size: 10px; padding-top: 8px; }
  .rail.thumbs { padding: 10px 8px; }
  .thumb-grid { grid-template-columns: 1fr; gap: 6px; }
  .thumb-head { font-size: 11px; margin-bottom: 8px; }
  .layer-panel { width: 140px; max-height: calc(100% - 80px); top: 8px; left: 8px; }
  .layer-panel.collapsed { width: 96px; }
  .piece-bar { padding: 6px 10px; gap: 10px; }
  .opacity-control input[type="range"] { width: 100px; }
  .grid-label { display: none; }
}