body {
  overflow: hidden;
  display: flex;
  flex-direction: column;
  height: 100vh;
  user-select: none;
  -webkit-user-select: none;
}

#app {
  display: flex;
  flex-direction: column;
  flex: 1;
  min-height: 0;
}

/* ---- Toolbar ---- */
#toolbar {
  display: flex;
  align-items: center;
  gap: 6px;
  padding: 4px 8px;
  border-bottom: 1px solid var(--sz-color-button-shadow);
  flex-shrink: 0;
  flex-wrap: wrap;
}

#toolbar label {
  font-size: 11px;
  font-weight: bold;
}

#toolbar select {
  font-size: 11px;
  max-width: 180px;
}

#toolbar button {
  font-size: 11px;
  padding: 1px 8px;
  min-width: 48px;
}

#toolbar button.toggled {
  font-weight: bold;
  outline: 2px solid var(--sz-color-highlight);
}

#drop-hint {
  font-size: 10px;
  color: var(--sz-color-gray-text);
  margin-left: auto;
}

/* ---- Main area ---- */
#main-area {
  flex: 1;
  min-height: 0;
  overflow: auto;
  padding: 8px;
  position: relative;
  background: repeating-conic-gradient(#e0e0e0 0% 25%, #f5f5f5 0% 50%) 0 0 / 16px 16px;
}

/* ---- Drop overlay ---- */
#drop-overlay {
  display: none;
  position: absolute;
  inset: 0;
  z-index: 100;
  background: rgba(0, 100, 200, 0.2);
  border: 3px dashed var(--sz-color-highlight);
  font-size: 18px;
  font-weight: bold;
  color: var(--sz-color-highlight);
  justify-content: center;
  align-items: center;
}

#main-area.dragging #drop-overlay {
  display: flex;
}

/* ---- 9-piece frame grid ---- */
#frame-grid {
  display: grid;
  gap: 4px;
  grid-template-columns:
    var(--grid-left, 40px)
    var(--grid-nw-ext, 0px)
    1fr
    var(--grid-ne-ext, 0px)
    var(--grid-right, 40px);
  grid-template-rows:
    var(--grid-top, 30px)
    minmax(200px, 1fr)
    var(--grid-bottom, 10px);
  grid-template-areas:
    "nw nw n  ne ne"
    "w  c  c  c  e"
    "sw s  s  s  se";
  min-width: 400px;
  min-height: 300px;
}

.frame-cell {
  position: relative;
  overflow: hidden;
  background-repeat: no-repeat;
  background-size: 100% 100%;
  outline: 1px dashed rgba(255, 0, 0, 0.4);
}

.cell-label {
  position: absolute;
  top: 1px;
  left: 1px;
  font-size: 9px;
  font-weight: bold;
  color: #fff;
  background: rgba(0, 0, 0, 0.55);
  padding: 0 3px;
  border-radius: 2px;
  pointer-events: none;
  z-index: 1;
  white-space: nowrap;
}

#cell-nw  { grid-area: nw; }
#cell-n   { grid-area: n; }
#cell-ne  { grid-area: ne; }
#cell-w   { grid-area: w; }
#cell-content { grid-area: c; background: var(--sz-color-window, #fff); overflow: auto; }
#cell-e   { grid-area: e; }
#cell-sw  { grid-area: sw; }
#cell-s   { grid-area: s; }
#cell-se  { grid-area: se; }

/* ---- Content area controls ---- */
#controls-area {
  padding: 8px;
  display: flex;
  flex-direction: column;
  gap: 8px;
}

#controls-area fieldset {
  border: 1px solid var(--sz-color-button-shadow);
  padding: 6px 8px;
}

#controls-area legend {
  font-size: 11px;
  font-weight: bold;
  padding: 0 4px;
}

.ctrl-row {
  display: flex;
  align-items: center;
  gap: 6px;
  margin-top: 4px;
  flex-wrap: wrap;
}

.ctrl-row label {
  font-size: 11px;
  display: flex;
  align-items: center;
  gap: 3px;
}

#scroll-test {
  height: 60px;
  overflow-y: scroll;
  border: 1px solid var(--sz-color-button-shadow);
  background: var(--sz-color-window, #fff);
  font-size: 11px;
  padding: 2px;
}

/* ---- Info panel ---- */
#info-panel {
  flex-shrink: 0;
  max-height: 180px;
  overflow-y: auto;
  border-top: 1px solid var(--sz-color-button-shadow);
  padding: 4px 8px;
  font-size: 10px;
  font-family: 'Consolas', 'Lucida Console', monospace;
  background: var(--sz-color-window, #fff);
}

#info-content {
  white-space: pre-wrap;
  line-height: 1.5;
}

.info-section {
  margin-bottom: 4px;
}

.info-section b {
  color: var(--sz-color-button-text, #000);
}

.info-warn {
  color: #c00;
  font-weight: bold;
}

.info-ok {
  color: #080;
}