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

:root {
  --bg: #1a1a2e;
  --bg-sidebar: #16213e;
  --bg-input: #0f3460;
  --text: #e0e0e0;
  --text-muted: #8888aa;
  --accent: #e94560;
  --accent-hover: #ff6b81;
  --border: #2a2a4a;
  --item-hover: #1a1a3e;
  --item-active: #2a1a3e;
  --error-bg: #4a1020;
  --error-text: #ff8899;
}

html, body {
  height: 100%;
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', system-ui, sans-serif;
  font-size: 14px;
  color: var(--text);
  background: var(--bg);
}

/* ── Layout ──────────────────────────────────────── */
.layout {
  display: flex;
  height: 100vh;
  overflow: hidden;
}

/* ── Sidebar ─────────────────────────────────────── */
.sidebar {
  width: 340px;
  min-width: 280px;
  background: var(--bg-sidebar);
  border-right: 1px solid var(--border);
  display: flex;
  flex-direction: column;
  overflow: hidden;
}

.sidebar-title {
  font-size: 16px;
  font-weight: 700;
  padding: 16px;
  border-bottom: 1px solid var(--border);
  color: var(--accent);
  letter-spacing: 0.5px;
}

.sidebar-section {
  padding: 12px 16px;
  border-bottom: 1px solid var(--border);
}

.sidebar-section h2 {
  font-size: 11px;
  text-transform: uppercase;
  letter-spacing: 1px;
  color: var(--text-muted);
  margin-bottom: 8px;
}

/* ── Sample Images ───────────────────────────────── */
.sample-images {
  display: flex;
  flex-wrap: wrap;
  gap: 6px;
  margin-bottom: 10px;
}

.sample-thumb {
  border: 2px solid transparent;
  border-radius: 4px;
  padding: 0;
  background: var(--bg-secondary);
  cursor: pointer;
  overflow: hidden;
  width: 56px;
  height: 48px;
  flex-shrink: 0;
  transition: border-color 0.15s;
}

.sample-thumb img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  display: block;
  image-rendering: pixelated;
}

.sample-thumb:hover {
  border-color: var(--text-muted);
}

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

/* ── File Input ──────────────────────────────────── */
.file-label {
  display: block;
  cursor: pointer;
}

.file-label input[type="file"] {
  display: none;
}

.file-label span {
  display: block;
  text-align: center;
  padding: 8px 12px;
  background: var(--bg-input);
  border: 1px dashed var(--border);
  border-radius: 6px;
  color: var(--text-muted);
  font-size: 13px;
  transition: border-color 0.2s, color 0.2s;
}

.file-label:hover span {
  border-color: var(--accent);
  color: var(--text);
}

/* ── Filters ─────────────────────────────────────── */
.filter-row {
  display: flex;
  gap: 6px;
  margin-bottom: 8px;
}

.filter-row select,
#search-input {
  flex: 1;
  padding: 6px 8px;
  background: var(--bg-input);
  border: 1px solid var(--border);
  border-radius: 4px;
  color: var(--text);
  font-size: 13px;
  outline: none;
}

#search-input {
  width: 100%;
}

.filter-row select:focus,
#search-input:focus {
  border-color: var(--accent);
}

/* ── Shader List ─────────────────────────────────── */
.shader-list {
  flex: 1;
  overflow-y: auto;
  border-bottom: 1px solid var(--border);
}

.shader-item {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 8px 16px;
  cursor: pointer;
  border-bottom: 1px solid var(--border);
  transition: background 0.15s;
}

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

.shader-item.active {
  background: var(--item-active);
  border-left: 3px solid var(--accent);
  padding-left: 13px;
}

.shader-name {
  font-size: 13px;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
  flex: 1;
  margin-right: 8px;
}

.shader-meta {
  font-size: 11px;
  color: var(--text-muted);
  white-space: nowrap;
}

/* ── Parameter Panel ─────────────────────────────── */
#param-panel {
  max-height: 300px;
  overflow-y: auto;
}

.no-params {
  color: var(--text-muted);
  font-size: 13px;
  font-style: italic;
}

.param-reset {
  display: block;
  width: 100%;
  padding: 6px;
  margin-bottom: 10px;
  background: var(--bg-input);
  border: 1px solid var(--border);
  border-radius: 4px;
  color: var(--text-muted);
  font-size: 12px;
  cursor: pointer;
  transition: color 0.2s, border-color 0.2s;
}

.param-reset:hover {
  color: var(--text);
  border-color: var(--accent);
}

.param-row {
  margin-bottom: 8px;
}

.param-label {
  display: block;
  font-size: 12px;
  color: var(--text-muted);
  margin-bottom: 2px;
}

.param-slider {
  width: calc(100% - 50px);
  vertical-align: middle;
  accent-color: var(--accent);
}

.param-value {
  display: inline-block;
  width: 44px;
  text-align: right;
  font-size: 12px;
  font-family: monospace;
  color: var(--text);
  vertical-align: middle;
}

/* ── Main Area ───────────────────────────────────── */
.main {
  flex: 1;
  display: flex;
  flex-direction: column;
  overflow: hidden;
}

.shader-info {
  padding: 10px 16px;
  font-size: 13px;
  color: var(--text-muted);
  border-bottom: 1px solid var(--border);
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

.error-display {
  padding: 10px 16px;
  background: var(--error-bg);
  color: var(--error-text);
  font-family: monospace;
  font-size: 12px;
  white-space: pre-wrap;
  max-height: 200px;
  overflow-y: auto;
}

.canvas-wrapper {
  flex: 1;
  position: relative;
  background: #000;
}

.canvas-wrapper canvas {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
}

/* ── Compare Toggle ──────────────────────────────── */
.compare-toggle {
  display: flex;
  align-items: center;
  gap: 8px;
  margin-top: 8px;
  cursor: pointer;
  font-size: 13px;
  color: var(--text-muted);
}

.compare-toggle input[type="checkbox"] {
  accent-color: var(--accent);
}

/* ── Comparison Slider ───────────────────────────── */
.compare-slider {
  position: absolute;
  inset: 0;
  z-index: 10;
  cursor: ew-resize;
}

.compare-line {
  position: absolute;
  top: 0;
  bottom: 0;
  left: 50%;
  width: 2px;
  background: #fff;
  box-shadow: 0 0 4px rgba(0,0,0,0.7);
  pointer-events: none;
  transform: translateX(-1px);
}

.compare-handle {
  position: absolute;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  display: flex;
  gap: 0;
  pointer-events: none;
}

.compare-label {
  display: block;
  padding: 4px 10px;
  font-size: 11px;
  font-weight: 600;
  letter-spacing: 0.5px;
  text-transform: uppercase;
  color: #fff;
  text-shadow: 0 1px 3px rgba(0,0,0,0.8);
}

.compare-label-left {
  background: rgba(0,0,0,0.55);
  border-radius: 4px 0 0 4px;
}

.compare-label-right {
  background: rgba(233,69,96,0.65);
  border-radius: 0 4px 4px 0;
}

/* ── Scrollbar Styling ───────────────────────────── */
::-webkit-scrollbar {
  width: 6px;
}

::-webkit-scrollbar-track {
  background: transparent;
}

::-webkit-scrollbar-thumb {
  background: var(--border);
  border-radius: 3px;
}

::-webkit-scrollbar-thumb:hover {
  background: var(--text-muted);
}