/* ===================================================================
   Day 20 — WebGL Shader Playground
   Premium dark theme with glassmorphism, neon accents, micro-animations
   =================================================================== */

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

:root {
  /* Surfaces */
  --bg-deep:      #0a0a0f;
  --bg-panel:     #12121a;
  --bg-toolbar:   rgba(18, 18, 26, 0.72);
  --bg-editor:    #0d0d14;
  --border-subtle: rgba(255, 255, 255, 0.06);
  --border-glow:   rgba(6, 182, 212, 0.2);

  /* Accents */
  --cyan:    #06b6d4;
  --magenta: #a855f7;
  --pink:    #ec4899;
  --green:   #22c55e;
  --red:     #ef4444;
  --amber:   #f59e0b;
  --orange:  #f97316;

  /* Text */
  --text-primary:   #e2e8f0;
  --text-secondary: #94a3b8;
  --text-muted:     #475569;

  /* Fonts */
  --font-code: 'JetBrains Mono', 'Fira Code', 'Cascadia Code', monospace;
  --font-ui:   'Inter', -apple-system, 'Segoe UI', sans-serif;

  /* Layout */
  --toolbar-h: 52px;
  --editor-ratio: 0.45;
  --divider-w: 5px;

  /* Transitions */
  --ease-out: cubic-bezier(0.16, 1, 0.3, 1);
  --ease-spring: cubic-bezier(0.34, 1.56, 0.64, 1);
}

html, body {
  height: 100%;
  overflow: hidden;
  background: var(--bg-deep);
  color: var(--text-primary);
  font-family: var(--font-ui);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

/* Subtle background dot-grid pattern */
body::before {
  content: '';
  position: fixed;
  inset: 0;
  background-image: radial-gradient(circle, rgba(255,255,255,0.03) 1px, transparent 1px);
  background-size: 24px 24px;
  pointer-events: none;
  z-index: 0;
}

/* ─── Shell ─── */
.playground-shell {
  position: relative;
  width: 100%;
  height: 100%;
  z-index: 1;
}

.playground-shell__inner {
  display: flex;
  flex-direction: column;
  width: 100%;
  height: 100%;
}

/* ─── Toolbar ─── */
.toolbar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: var(--toolbar-h);
  padding: 0 16px;
  background: var(--bg-toolbar);
  backdrop-filter: blur(16px) saturate(1.4);
  -webkit-backdrop-filter: blur(16px) saturate(1.4);
  border-bottom: 1px solid var(--border-subtle);
  flex-shrink: 0;
  z-index: 10;
}

.toolbar__left,
.toolbar__center,
.toolbar__right {
  display: flex;
  align-items: center;
  gap: 10px;
}

.toolbar__left  { flex: 1; }
.toolbar__right { flex: 1; justify-content: flex-end; }

/* Back arrow */
.toolbar__back {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 32px;
  height: 32px;
  border-radius: 8px;
  color: var(--text-secondary);
  background: transparent;
  border: 1px solid var(--border-subtle);
  text-decoration: none;
  transition: all 0.2s var(--ease-out);
}
.toolbar__back:hover {
  color: var(--text-primary);
  border-color: var(--border-glow);
  background: rgba(6, 182, 212, 0.06);
}

/* Brand */
.toolbar__brand {
  display: flex;
  flex-direction: column;
  gap: 0;
}
.toolbar__day {
  font-size: 10px;
  font-weight: 500;
  color: var(--cyan);
  letter-spacing: 0.08em;
  text-transform: uppercase;
  line-height: 1;
}
.toolbar__title {
  font-size: 14px;
  font-weight: 700;
  color: var(--text-primary);
  line-height: 1.2;
}

/* Preset selector */
.preset-selector {
  position: relative;
  display: flex;
  align-items: center;
  gap: 8px;
  cursor: pointer;
}
.preset-selector__label {
  font-size: 11px;
  font-weight: 600;
  color: var(--text-muted);
  text-transform: uppercase;
  letter-spacing: 0.08em;
}
.preset-selector__select {
  appearance: none;
  -webkit-appearance: none;
  background: rgba(255, 255, 255, 0.04);
  border: 1px solid var(--border-subtle);
  border-radius: 8px;
  color: var(--text-primary);
  font-family: var(--font-ui);
  font-size: 13px;
  font-weight: 500;
  padding: 6px 32px 6px 12px;
  cursor: pointer;
  transition: all 0.2s var(--ease-out);
  outline: none;
  min-width: 160px;
}
.preset-selector__select:hover {
  border-color: var(--border-glow);
  background: rgba(6, 182, 212, 0.06);
}
.preset-selector__select:focus-visible {
  border-color: var(--cyan);
  box-shadow: 0 0 0 2px rgba(6, 182, 212, 0.15);
}
.preset-selector__select option {
  background: var(--bg-panel);
  color: var(--text-primary);
}
.preset-selector__chevron {
  position: absolute;
  right: 10px;
  color: var(--text-secondary);
  pointer-events: none;
}

/* Toolbar buttons */
.toolbar__btn {
  display: flex;
  align-items: center;
  gap: 6px;
  padding: 6px 12px;
  border: 1px solid var(--border-subtle);
  border-radius: 8px;
  background: rgba(255, 255, 255, 0.03);
  color: var(--text-secondary);
  font-family: var(--font-ui);
  font-size: 12px;
  font-weight: 500;
  cursor: pointer;
  transition: all 0.2s var(--ease-out);
  outline: none;
  white-space: nowrap;
}
.toolbar__btn:hover {
  color: var(--text-primary);
  border-color: var(--border-glow);
  background: rgba(6, 182, 212, 0.06);
}
.toolbar__btn:active {
  transform: scale(0.96);
}
.toolbar__btn-label {
  display: inline;
}

/* FPS badge */
.fps-badge {
  font-family: var(--font-code);
  font-size: 11px;
  font-weight: 500;
  color: var(--green);
  background: rgba(34, 197, 94, 0.08);
  border: 1px solid rgba(34, 197, 94, 0.15);
  padding: 3px 8px;
  border-radius: 6px;
  letter-spacing: 0.02em;
}

/* ─── Panels Container ─── */
.panels {
  display: flex;
  flex: 1;
  min-height: 0;
  position: relative;
}

/* Individual panel */
.panel {
  position: relative;
  overflow: hidden;
}

.panel--editor {
  display: flex;
  flex-direction: column;
  flex: 0 0 45%;
  background: var(--bg-editor);
  border-right: none;
}

.panel--canvas {
  flex: 1;
  background: #000;
  display: flex;
  align-items: stretch;
  justify-content: stretch;
}

/* ─── Editor Header (fake title bar) ─── */
.editor-header {
  display: flex;
  align-items: center;
  gap: 6px;
  height: 34px;
  padding: 0 14px;
  background: rgba(255, 255, 255, 0.02);
  border-bottom: 1px solid var(--border-subtle);
  flex-shrink: 0;
}

.editor-header__dot {
  width: 10px;
  height: 10px;
  border-radius: 50%;
}
.editor-header__dot--red    { background: #ff5f57; }
.editor-header__dot--yellow { background: #febc2e; }
.editor-header__dot--green  { background: #28c840; }

.editor-header__filename {
  font-family: var(--font-code);
  font-size: 11px;
  color: var(--text-muted);
  margin-left: 8px;
}

.compile-badge {
  margin-left: auto;
  font-family: var(--font-code);
  font-size: 10px;
  font-weight: 500;
  padding: 2px 8px;
  border-radius: 4px;
  letter-spacing: 0.02em;
}
.compile-badge--ok {
  color: var(--green);
  background: rgba(34, 197, 94, 0.08);
}
.compile-badge--error {
  color: var(--red);
  background: rgba(239, 68, 68, 0.08);
}

/* ─── Editor Area ─── */
.editor-wrap {
  display: flex;
  flex: 1;
  min-height: 0;
  overflow: hidden;
  position: relative;
}

/* Line numbers */
.line-numbers {
  width: 48px;
  padding: 12px 8px 12px 0;
  background: var(--bg-editor);
  border-right: 1px solid var(--border-subtle);
  overflow: hidden;
  flex-shrink: 0;
  font-family: var(--font-code);
  font-size: 13px;
  line-height: 1.6;
  color: var(--text-muted);
  text-align: right;
  user-select: none;
  -webkit-user-select: none;
}

/* Editor layers (highlight + textarea stacked) */
.editor-layers {
  position: relative;
  flex: 1;
  min-width: 0;
  overflow: auto;
}

.highlight-layer,
.code-textarea {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  min-height: 100%;
  padding: 12px 14px;
  font-family: var(--font-code);
  font-size: 13px;
  line-height: 1.6;
  tab-size: 2;
  -moz-tab-size: 2;
  white-space: pre;
  word-wrap: normal;
  overflow-wrap: normal;
}

.highlight-layer {
  margin: 0;
  pointer-events: none;
  color: var(--text-primary);
  z-index: 1;
}
.highlight-layer code {
  font-family: inherit;
  font-size: inherit;
  line-height: inherit;
}

.code-textarea {
  background: transparent;
  color: var(--text-primary);
  caret-color: var(--cyan);
  border: none;
  outline: none;
  resize: none;
  z-index: 2;
  /* Make text invisible so highlight shows through but caret remains */
  color: transparent;
  -webkit-text-fill-color: transparent;
}
.code-textarea::selection {
  background: rgba(6, 182, 212, 0.2);
  -webkit-text-fill-color: transparent;
}

/* ─── Divider ─── */
.divider {
  width: var(--divider-w);
  cursor: col-resize;
  background: var(--border-subtle);
  flex-shrink: 0;
  position: relative;
  z-index: 5;
  transition: background 0.2s;
}
.divider::after {
  content: '';
  position: absolute;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  width: 3px;
  height: 32px;
  border-radius: 3px;
  background: var(--text-muted);
  opacity: 0.4;
  transition: opacity 0.2s, background 0.2s;
}
.divider:hover,
.divider.dragging {
  background: var(--cyan);
}
.divider:hover::after,
.divider.dragging::after {
  opacity: 1;
  background: var(--cyan);
}

/* ─── Canvas ─── */
#gl-canvas {
  display: block;
  width: 100%;
  height: 100%;
}

/* ─── Error Overlay ─── */
.error-overlay {
  position: absolute;
  inset: 0;
  display: flex;
  align-items: center;
  justify-content: center;
  background: rgba(10, 10, 15, 0.88);
  backdrop-filter: blur(6px);
  z-index: 6;
  animation: errorFadeIn 0.25s var(--ease-out);
}
.error-overlay[hidden] {
  display: none;
}
@keyframes errorFadeIn {
  from { opacity: 0; }
  to   { opacity: 1; }
}

.error-overlay__inner {
  max-width: 480px;
  padding: 24px 28px;
  background: rgba(239, 68, 68, 0.06);
  border: 1px solid rgba(239, 68, 68, 0.2);
  border-radius: 12px;
  text-align: center;
}
.error-overlay__icon {
  font-size: 28px;
  display: block;
  margin-bottom: 8px;
}
.error-overlay__title {
  font-size: 14px;
  font-weight: 600;
  color: var(--red);
  margin-bottom: 12px;
}
.error-overlay__msg {
  font-family: var(--font-code);
  font-size: 12px;
  line-height: 1.5;
  color: #fca5a5;
  text-align: left;
  white-space: pre-wrap;
  word-break: break-word;
  max-height: 200px;
  overflow-y: auto;
}

/* ─── Toast ─── */
.toast {
  position: fixed;
  bottom: 20px;
  left: 50%;
  transform: translateX(-50%) translateY(100px);
  padding: 10px 20px;
  background: var(--bg-toolbar);
  backdrop-filter: blur(12px);
  border: 1px solid var(--border-glow);
  border-radius: 10px;
  font-size: 13px;
  font-weight: 500;
  color: var(--cyan);
  pointer-events: none;
  opacity: 0;
  transition: all 0.35s var(--ease-spring);
  z-index: 100;
}
.toast.show {
  transform: translateX(-50%) translateY(0);
  opacity: 1;
}

/* ─── Noscript ─── */
.no-script {
  display: flex;
  align-items: center;
  justify-content: center;
  position: fixed;
  inset: 0;
  background: var(--bg-deep);
  color: var(--text-secondary);
  font-family: var(--font-ui);
  font-size: 16px;
}

/* ─── Syntax Highlighting Colors ─── */
.hl-keyword  { color: #c084fc; }                /* Soft magenta/purple */
.hl-type     { color: #22d3ee; }                /* Bright cyan */
.hl-builtin  { color: #fb923c; }                /* Warm orange */
.hl-number   { color: #4ade80; }                /* Fresh green */
.hl-comment  { color: #475569; font-style: italic; } /* Muted slate */
.hl-preproc  { color: #fbbf24; }                /* Amber/yellow */

/* ─── Responsive: Stack on Mobile ─── */
@media (max-width: 768px) {
  .toolbar {
    padding: 0 10px;
    height: 46px;
    gap: 6px;
  }
  .toolbar__brand { display: none; }
  .toolbar__btn-label { display: none; }
  .toolbar__btn { padding: 6px 8px; }
  .preset-selector__label { display: none; }
  .preset-selector__select {
    min-width: 120px;
    font-size: 12px;
    padding: 5px 28px 5px 8px;
  }
  .fps-badge { font-size: 10px; padding: 2px 6px; }

  /* Stack panels vertically */
  .panels {
    flex-direction: column;
  }
  .panel--editor {
    flex: 0 0 45%;
    border-right: none;
    border-bottom: 1px solid var(--border-subtle);
  }
  .panel--canvas {
    flex: 1;
  }
  .divider {
    width: 100%;
    height: var(--divider-w);
    cursor: row-resize;
  }
  .divider::after {
    width: 32px;
    height: 3px;
  }

  .editor-header { padding: 0 10px; }
  .line-numbers { width: 36px; font-size: 11px; }
  .highlight-layer, .code-textarea {
    font-size: 12px;
    padding: 10px 10px;
  }
}

@media (max-width: 480px) {
  .toolbar__left { flex: 0; gap: 6px; }
  .toolbar__center { flex: 1; }
  .toolbar__right { gap: 4px; }
  .preset-selector__select {
    min-width: 100px;
    font-size: 11px;
  }
}

/* ─── Fullscreen Canvas Mode ─── */
.panel--canvas:fullscreen {
  background: #000;
}
.panel--canvas:fullscreen #gl-canvas {
  width: 100vw;
  height: 100vh;
}