:root {
  color-scheme: light;
  font-family: Inter, ui-sans-serif, system-ui, sans-serif;
  --panel-bg: #ffffff;
  --border: #d8dee9;
  --accent: #4f46e5;
  --highlight: rgba(79, 70, 229, 0.16);
  --text-muted: #64748b;
}

* {
  box-sizing: border-box;
}

html,
body {
  height: 100%;
  margin: 0;
  background: #f4f7fb;
  color: #1f2937;
}

body {
  padding: 16px;
}

.app-shell {
  display: grid;
  grid-template-columns: var(--pages-width, 280px) 8px minmax(0, 1fr) 8px var(--slots-width, 340px);
  gap: 16px;
  align-items: start;
  min-height: calc(100vh - 164px);
}

.pages-resizer,
.slots-resizer {
  align-self: stretch;
  position: relative;
  width: 8px;
  min-height: 100%;
  border: 0;
  border-radius: 999px;
  background: transparent;
  cursor: col-resize;
  touch-action: none;
}

.pages-resizer::after,
.slots-resizer::after {
  content: "";
  position: absolute;
  inset: 0 2px;
  border-radius: inherit;
  background: var(--border);
  opacity: 0.9;
  transition: background 120ms ease, opacity 120ms ease;
}

.pages-resizer:hover::after,
.pages-resizer:focus-visible::after,
.pages-resizer.is-dragging::after,
.slots-resizer:hover::after,
.slots-resizer:focus-visible::after,
.slots-resizer.is-dragging::after {
  background: var(--accent);
  opacity: 1;
}

.pages-resizer:focus-visible,
.slots-resizer:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 3px;
}

.column-panel,
.center-column {
  display: grid;
  gap: 16px;
  align-content: start;
  min-height: 0;
}

.panel {
  background: var(--panel-bg);
  border: 1px solid var(--border);
  border-radius: 16px;
  padding: 16px;
  box-shadow: 0 1px 2px rgba(15, 23, 42, 0.04);
}

#pagesPanel,
#slotsPanel {
  max-height: calc(100vh - 164px);
  overflow-y: auto;
  overscroll-behavior: contain;
  scrollbar-gutter: stable;
  scrollbar-width: thin;
  scrollbar-color: #94a3b8 transparent;
}

#pagesPanel::-webkit-scrollbar,
#slotsPanel::-webkit-scrollbar {
  width: 10px;
}

#pagesPanel::-webkit-scrollbar-thumb,
#slotsPanel::-webkit-scrollbar-thumb {
  border: 3px solid transparent;
  border-radius: 999px;
  background: #94a3b8;
  background-clip: padding-box;
}

.toolbar {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 16px;
}

.toolbar-title h1 {
  margin: 0 0 6px;
  font-size: 24px;
}

.toolbar-title p {
  margin: 0;
  color: var(--text-muted);
  max-width: 720px;
}

.toolbar-actions {
  display: flex;
  gap: 10px;
  flex-wrap: wrap;
  align-items: center;
}

.file-label {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 10px 14px;
  border: 1px dashed var(--border);
  border-radius: 999px;
  cursor: pointer;
}

.file-label input {
  max-width: 160px;
}

button {
  appearance: none;
  border: 1px solid var(--border);
  border-radius: 10px;
  background: #f8fafc;
  padding: 10px 14px;
  cursor: pointer;
}

button:disabled {
  opacity: 0.5;
  cursor: default;
}

.status-line,
.status-message {
  margin: 0;
}

#statusPanel[data-level="warning"] {
  border-color: #f59e0b;
  background: #fff9eb;
}

#statusPanel[data-level="error"] {
  border-color: #ef4444;
  background: #fff1f2;
}

.help-panel h2 {
  margin: 0 0 8px;
  font-size: 16px;
}

.help-panel ol {
  margin: 0;
  padding-left: 20px;
  color: var(--text-muted);
  font-size: 13px;
  line-height: 1.6;
}

.preview-frame-shell {
  position: relative;
  display: grid;
  place-items: center;
  min-width: 0;
  min-height: 420px;
}

.preview-frame-shell::before {
  content: "";
  width: min(100%, 100%);
  aspect-ratio: 16 / 9;
  border: 1px solid var(--border);
  border-radius: 18px;
  background: linear-gradient(180deg, #fff, #f8fbff);
}

#previewFrame {
  position: absolute;
  width: min(100%, calc((100vh - 120px) * 16 / 9));
  height: auto;
  aspect-ratio: 16 / 9;
  border: 0;
  border-radius: 18px;
  overflow: hidden;
  background: white;
}

.locked-layout-label {
  position: absolute;
  top: 18px;
  right: 18px;
  z-index: 1;
  padding: 6px 10px;
  border-radius: 999px;
  background: rgba(17, 24, 39, 0.8);
  color: white;
  font-size: 12px;
  letter-spacing: 0.02em;
}

.page-list,
.slot-list {
  display: grid;
  gap: 10px;
}

.page-item,
.slot-card {
  width: 100%;
  text-align: left;
}

.page-item {
  display: grid;
  gap: 4px;
  background: white;
}

.page-thumbnail {
  width: 160px;
  max-width: 100%;
  height: auto;
  aspect-ratio: 16 / 9;
  justify-self: center;
  object-fit: cover;
  border: 1px solid var(--border);
  border-radius: 8px;
  background: #0f172a;
}

.thumbnail-progress {
  margin: -4px 0 10px;
  color: var(--muted);
  font-size: 0.78rem;
}

.page-item[data-selected="true"],
.slot-card[data-selected="true"] {
  border-color: var(--accent);
  box-shadow: 0 0 0 3px rgba(79, 70, 229, 0.12);
}

.page-index,
.page-slots,
.slot-type-badge,
.slot-lock-badge {
  color: var(--text-muted);
  font-size: 12px;
}

.page-label,
.slot-select-label {
  font-weight: 600;
}

.slot-card {
  display: grid;
  gap: 10px;
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 12px;
  background: #fbfdff;
}

.slot-select {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 0;
  border: 0;
  background: transparent;
}

.slot-meta,
.slot-toggle,
.slot-field {
  display: grid;
  gap: 6px;
}

.slot-field span {
  font-size: 12px;
  color: var(--text-muted);
}

.slot-field input[type="text"],
.slot-readonly {
  width: 100%;
  padding: 9px 10px;
  border: 1px solid var(--border);
  border-radius: 10px;
  background: white;
}

.slot-readonly {
  color: var(--text-muted);
}

.slot-toggle {
  grid-auto-flow: column;
  justify-content: start;
  align-items: center;
}

.empty-state {
  color: var(--text-muted);
  margin: 0;
}

#previewFrame[data-highlighted-slot]:not([data-highlighted-slot=""]) {
  box-shadow: 0 0 0 4px rgba(79, 70, 229, 0.14);
}

@media (max-width: 1200px) {
  .app-shell {
    grid-template-columns: 1fr;
  }

  .pages-resizer,
  .slots-resizer {
    display: none;
  }

  #pagesPanel,
  #slotsPanel {
    max-height: none;
    overflow-y: visible;
    scrollbar-gutter: auto;
  }
}