:root {
  --bg-editor: #1a2520;
  --bg-preview: #1f2d26;
  --bg-app: #0d1612;
  --bg-header: #0f1a14;
  --accent: #3d8b5f;
  --accent-soft: rgba(61, 139, 95, 0.2);
  --text-primary: #e8f4ed;
  --text-secondary: #8fb89d;
  --border: rgba(143, 184, 157, 0.16);
  --font-sans: 'Inter', system-ui, -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
}

*,
*::before,
*::after {
  box-sizing: border-box;
}

html,
body {
  margin: 0;
  height: 100%;
  color: var(--text-primary);
  font-family: var(--font-sans);
}

body {
  display: flex;
  align-items: stretch;
  justify-content: center;
  background: radial-gradient(circle at top, rgba(61, 139, 95, 0.15), transparent 60%), var(--bg-app);
}

.app-shell {
  flex: 1;
  display: grid;
  grid-template-columns: minmax(0, 1.8fr) minmax(240px, 1fr);
  grid-template-rows: auto 1fr;
  max-width: 1280px;
  width: 100%;
  height: 100vh;
  padding: 24px;
  column-gap: 24px;
  row-gap: 12px;
  min-height: 0;
  align-items: start;
}

.panel-title {
  margin: 0;
  display: inline-flex;
  align-items: center;
  gap: 12px;
  font-size: 16px;
  font-weight: 600;
  color: var(--text-secondary);
  letter-spacing: 0.05em;
  text-transform: uppercase;
}

.panel-icon {
  width: 30px;
  height: 30px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  border-radius: 999px;
  background: rgba(61, 139, 95, 0.25);
  color: var(--accent);
  font-weight: 600;
  font-size: 16px;
}

.editor-header {
  grid-column: 1;
  grid-row: 1;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
}

.editor-title {
  margin: 0;
}

#editor {
  grid-column: 1;
  grid-row: 2;
  min-height: 0;
  height: 100%;
  border-radius: 20px;
  background: var(--bg-editor);
  border: 1px solid var(--border);
  box-shadow: 0 20px 46px rgba(15, 23, 42, 0.45);
  overflow: hidden;
}

.preview-summary {
  grid-column: 2;
  grid-row: 1;
  justify-self: center;
  align-self: end;
  margin: 0;
  display: flex;
  align-items: center;
  gap: 8px;
  font-size: 14px;
  transition: color 0.2s ease;
  text-align: center;
  color: var(--text-secondary);
}

.preview-summary[data-tone="success"] {
  color: #34d399;
}

.preview-summary[data-tone="error"] {
  color: #f87171;
}

.preview-summary[data-tone="warning"] {
  color: #facc15;
}

.preview-code {
  grid-column: 2;
  grid-row: 2;
  min-height: 0;
  height: 100%;
  margin: 0;
  border-radius: 20px;
  background: rgba(15, 23, 42, 0.55);
  border: 1px solid var(--border);
  box-shadow: 0 20px 46px rgba(15, 23, 42, 0.45);
  padding: 20px;
  color: var(--text-primary);
  white-space: pre-wrap;
  word-break: break-word;
  font-family: Menlo, 'Fira Code', 'JetBrains Mono', monospace;
  font-size: 14px;
  line-height: 1.5;
  overflow: auto;
}

.preview-code[data-tone="error"] {
  color: #fca5a5;
}

.preview-code[data-tone="success"] {
  color: #bbf7d0;
}

.preview-code[data-tone="warning"] {
  color: #fde68a;
}

.example-picker {
  background: rgba(15, 23, 42, 0.6);
  border: 1px solid var(--border);
  border-radius: 10px;
  color: var(--text-primary);
  padding: 8px 32px 8px 14px;
  font-family: var(--font-sans);
  font-size: 13px;
  font-weight: 500;
  cursor: pointer;
  transition: background-color 0.2s ease, border-color 0.2s ease, box-shadow 0.2s ease;
  outline: none;
  appearance: none;
  background-image: url("data:image/svg+xml,%3Csvg width='10' height='6' viewBox='0 0 10 6' fill='none' xmlns='http://www.w3.org/2000/svg'%3E%3Cpath d='M1 1L5 5L9 1' stroke='%2394a3b8' stroke-width='1.5' stroke-linecap='round' stroke-linejoin='round'/%3E%3C/svg%3E");
  background-repeat: no-repeat;
  background-position: right 12px center;
}

.example-picker:hover {
  background: rgba(15, 23, 42, 0.8);
  border-color: var(--accent);
}

.example-picker:focus {
  border-color: var(--accent);
  box-shadow: 0 0 0 3px var(--accent-soft);
}

.example-picker option {
  background: var(--bg-editor);
  color: var(--text-primary);
  padding: 8px;
}


@media (max-width: 1024px) {
  .app-shell {
    grid-template-columns: 1fr;
    grid-template-rows: auto minmax(0, 1fr) auto minmax(0, 1fr);
  }

  .editor-header,
  #editor,
  .preview-summary,
  .preview-code {
    grid-column: 1;
  }

  .editor-header {
    grid-row: 1;
  }

  #editor {
    grid-row: 2;
  }

  .preview-summary {
    justify-self: flex-start;
    grid-row: 3;
  }

  .preview-code {
    grid-row: 4;
  }
}

@media (max-width: 720px) {
  .app-shell {
    padding: 16px;
    row-gap: 18px;
  }
}