/* === CSS Custom Properties === */
:root {
  --color-bg: #f8fafc;
  --color-surface: #ffffff;
  --color-text: #1e293b;
  --color-text-secondary: #64748b;
  --color-border: #e2e8f0;
  --color-accent: #2563eb;
  --color-accent-hover: #1d4ed8;
  --color-seo: #2563eb;
  --color-seo-bg: #eff6ff;
  --color-aeo: #16a34a;
  --color-aeo-bg: #f0fdf4;
  --color-geo: #7c3aed;
  --color-geo-bg: #f5f3ff;
  --color-error: #dc2626;
  --color-success: #16a34a;
  --color-warning: #f59e0b;
  --radius: 8px;
  --radius-lg: 12px;
  --shadow-sm: 0 1px 2px rgba(0,0,0,0.05);
  --shadow: 0 1px 3px rgba(0,0,0,0.1), 0 1px 2px rgba(0,0,0,0.06);
  --shadow-lg: 0 4px 6px rgba(0,0,0,0.07), 0 2px 4px rgba(0,0,0,0.06);
  --font-sans: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Noto Sans TC", "Microsoft JhengHei", sans-serif;
  --font-mono: "Cascadia Code", "Fira Code", "Source Code Pro", Consolas, monospace;
}

[data-theme="dark"] {
  --color-bg: #0f172a;
  --color-surface: #1e293b;
  --color-text: #f1f5f9;
  --color-text-secondary: #94a3b8;
  --color-border: #334155;
  --color-seo-bg: #1e3a5f;
  --color-aeo-bg: #14532d;
  --color-geo-bg: #2e1065;
  --shadow-sm: 0 1px 2px rgba(0,0,0,0.3);
  --shadow: 0 1px 3px rgba(0,0,0,0.4);
  --shadow-lg: 0 4px 6px rgba(0,0,0,0.4);
}

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

html { font-size: 16px; -webkit-font-smoothing: antialiased; }

body {
  font-family: var(--font-sans);
  background: var(--color-bg);
  color: var(--color-text);
  line-height: 1.6;
  min-height: 100vh;
}

/* === App Layout === */
.app-container {
  display: flex;
  flex-direction: column;
  min-height: 100vh;
}

.app-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 12px 24px;
  background: var(--color-surface);
  border-bottom: 1px solid var(--color-border);
  box-shadow: var(--shadow-sm);
  position: sticky;
  top: 0;
  z-index: 100;
}

.app-header h1 {
  font-size: 1.25rem;
  font-weight: 700;
  color: var(--color-accent);
  display: flex;
  align-items: center;
  gap: 8px;
}

.app-header h1 .logo-icon {
  width: 28px;
  height: 28px;
}

.header-actions {
  display: flex;
  align-items: center;
  gap: 8px;
}

.app-layout {
  display: grid;
  grid-template-columns: 380px 1fr;
  flex: 1;
  overflow: hidden;
}

.input-panel {
  background: var(--color-surface);
  border-right: 1px solid var(--color-border);
  padding: 24px;
  overflow-y: auto;
  height: calc(100vh - 57px);
}

.output-panel {
  display: flex;
  flex-direction: column;
  height: calc(100vh - 57px);
  overflow: hidden;
}

.output-toolbar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 8px 16px;
  border-bottom: 1px solid var(--color-border);
  background: var(--color-surface);
  gap: 8px;
  flex-shrink: 0;
}

.output-content {
  flex: 1;
  overflow-y: auto;
  padding: 24px;
  background: var(--color-bg);
}

.output-footer {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 8px 16px;
  border-top: 1px solid var(--color-border);
  background: var(--color-surface);
  font-size: 0.85rem;
  color: var(--color-text-secondary);
  flex-shrink: 0;
}

/* === Responsive === */
@media (max-width: 900px) {
  .app-layout {
    grid-template-columns: 1fr;
  }
  .input-panel {
    height: auto;
    border-right: none;
    border-bottom: 1px solid var(--color-border);
  }
  .output-panel {
    height: auto;
    min-height: 60vh;
  }
}

/* === Scrollbar === */
::-webkit-scrollbar { width: 6px; }
::-webkit-scrollbar-track { background: transparent; }
::-webkit-scrollbar-thumb { background: var(--color-border); border-radius: 3px; }
::-webkit-scrollbar-thumb:hover { background: var(--color-text-secondary); }

/* === Selection === */
::selection {
  background: var(--color-accent);
  color: white;
}