/* ============================
   1. CSS Custom Properties
   ============================ */
:root {
  /* Brand colors */
  --color-brand:        #2563eb;
  --color-brand-dark:   #1d4ed8;
  --color-brand-light:  #eff6ff;
  --color-success:      #16a34a;
  --color-error:        #dc2626;

  /* Neutrals */
  --color-bg:           #f8fafc;
  --color-surface:      #ffffff;
  --color-border:       #e2e8f0;
  --color-text:         #1e293b;
  --color-text-muted:   #64748b;
  --color-header-bg:    #1e293b;
  --color-footer-bg:    #0f172a;

  /* Ad placeholders */
  --color-ad-bg:        #f1f5f9;
  --color-ad-border:    #94a3b8;

  /* Typography */
  --font-sans: system-ui, -apple-system, 'Segoe UI', Roboto, Helvetica, Arial, sans-serif;
  --font-mono: 'Cascadia Code', 'Fira Code', 'Consolas', 'Monaco', 'Courier New', monospace;

  /* Spacing */
  --space-xs:  0.25rem;
  --space-sm:  0.5rem;
  --space-md:  1rem;
  --space-lg:  1.5rem;
  --space-xl:  2rem;
  --space-2xl: 3rem;

  /* Borders & Radius */
  --radius-sm: 4px;
  --radius-md: 8px;
  --radius-lg: 12px;

  /* Shadows */
  --shadow-sm: 0 1px 3px rgba(0, 0, 0, 0.08);
  --shadow-md: 0 4px 12px rgba(0, 0, 0, 0.10);

  /* Transitions */
  --transition-fast: 150ms ease;

  /* Layout */
  --container-max:   1100px;
  --textarea-height: 420px;
}


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

html {
  font-size: 16px;
  scroll-behavior: smooth;
}

body {
  font-family: var(--font-sans);
  font-size: 1rem;
  line-height: 1.6;
  background-color: var(--color-bg);
  color: var(--color-text);
}

a {
  color: var(--color-brand);
  text-decoration: none;
}

a:hover {
  text-decoration: underline;
}

code {
  font-family: var(--font-mono);
  font-size: 0.875em;
  background: var(--color-border);
  padding: 0.1em 0.35em;
  border-radius: var(--radius-sm);
}


/* ============================
   3. Layout — Container
   ============================ */
.container {
  max-width: var(--container-max);
  margin-inline: auto;
  padding-inline: var(--space-lg);
}


/* ============================
   4. Site Header
   ============================ */
.site-header {
  background-color: var(--color-header-bg);
  color: #ffffff;
  padding: var(--space-xl) 0 var(--space-lg);
  border-bottom: 3px solid var(--color-brand);
}

.site-title {
  font-size: 2rem;
  font-weight: 800;
  letter-spacing: -0.025em;
  color: #ffffff;
  margin-bottom: var(--space-xs);
}

.site-subtitle {
  font-size: 0.9375rem;
  color: #94a3b8;
  font-weight: 500;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  margin-bottom: var(--space-sm);
}

.site-intro {
  font-size: 1rem;
  color: #cbd5e1;
  max-width: 600px;
}


/* ============================
   5. Ad Containers
   ============================ */
.ad-container {
  display: flex;
  align-items: center;
  justify-content: center;
  background-color: var(--color-ad-bg);
  border: 1px dashed var(--color-ad-border);
  border-radius: var(--radius-sm);
  margin-block: var(--space-xl);
  overflow: hidden;
}

.ad-top {
  min-height: 90px;
  max-width: 728px;
  margin-inline: auto;
}

.ad-content {
  min-height: 250px;
  width: 300px;
  flex-shrink: 0;
  float: right;
  margin-left: var(--space-xl);
  margin-bottom: var(--space-md);
}

.ad-footer {
  min-height: 60px;
  max-width: 468px;
  margin-inline: auto;
}

.ad-placeholder {
  font-size: 0.75rem;
  font-weight: 500;
  color: var(--color-text-muted);
  text-align: center;
  padding: var(--space-sm);
  pointer-events: none;
  user-select: none;
}


/* ============================
   6. Tab Navigation
   ============================ */
.tab-nav {
  display: flex;
  gap: 0;
  border-bottom: 2px solid var(--color-border);
  margin-bottom: var(--space-lg);
}

.tab-btn {
  padding: var(--space-sm) var(--space-xl);
  background: none;
  border: none;
  border-bottom: 3px solid transparent;
  margin-bottom: -2px;
  font-family: var(--font-sans);
  font-size: 0.9375rem;
  font-weight: 600;
  color: var(--color-text-muted);
  cursor: pointer;
  transition: color var(--transition-fast), border-color var(--transition-fast);
  white-space: nowrap;
}

.tab-btn:hover {
  color: var(--color-brand);
}

.tab-btn--active {
  color: var(--color-brand);
  border-bottom-color: var(--color-brand);
}

.tab-btn:focus-visible {
  outline: 2px solid var(--color-brand);
  outline-offset: 2px;
  border-radius: var(--radius-sm) var(--radius-sm) 0 0;
}


/* ============================
   7. Tool Panels
   ============================ */
.tool-panel {
  display: block;
}

.tool-panel--hidden {
  display: none;
}


/* ============================
   8. Editor Grid
   ============================ */
.editor-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: var(--space-lg);
  margin-bottom: var(--space-md);
}

.editor-pane {
  display: flex;
  flex-direction: column;
  gap: var(--space-xs);
}

.editor-label {
  font-size: 0.8125rem;
  font-weight: 700;
  color: var(--color-text-muted);
  text-transform: uppercase;
  letter-spacing: 0.05em;
}


/* ============================
   9. Textareas
   ============================ */
.editor-textarea {
  width: 100%;
  height: var(--textarea-height);
  padding: var(--space-md);
  font-family: var(--font-mono);
  font-size: 0.875rem;
  line-height: 1.6;
  background-color: var(--color-surface);
  color: var(--color-text);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  resize: vertical;
  transition: border-color var(--transition-fast), box-shadow var(--transition-fast);
}

.editor-textarea:focus {
  outline: none;
  border-color: var(--color-brand);
  box-shadow: 0 0 0 3px rgba(37, 99, 235, 0.15);
}

.editor-textarea--output {
  background-color: var(--color-bg);
  cursor: default;
  color: #166534; /* dark green for output */
}

.editor-textarea--error {
  border-color: var(--color-error) !important;
  box-shadow: 0 0 0 3px rgba(220, 38, 38, 0.12) !important;
}


/* ============================
   10. Buttons
   ============================ */
.btn-group {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-sm);
  margin-bottom: var(--space-sm);
}

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 0.5rem 1.25rem;
  font-family: var(--font-sans);
  font-size: 0.9375rem;
  font-weight: 600;
  border-radius: var(--radius-md);
  border: 1px solid transparent;
  cursor: pointer;
  transition:
    background-color var(--transition-fast),
    border-color var(--transition-fast),
    color var(--transition-fast),
    transform var(--transition-fast),
    box-shadow var(--transition-fast);
  user-select: none;
  white-space: nowrap;
}

.btn:active {
  transform: translateY(1px);
}

.btn:focus-visible {
  outline: 2px solid var(--color-brand);
  outline-offset: 2px;
}

.btn:disabled {
  opacity: 0.45;
  cursor: not-allowed;
}

.btn:disabled:active {
  transform: none;
}

/* Primary — filled brand */
.btn--primary {
  background-color: var(--color-brand);
  color: #ffffff;
  border-color: var(--color-brand);
}

.btn--primary:hover:not(:disabled) {
  background-color: var(--color-brand-dark);
  border-color: var(--color-brand-dark);
  box-shadow: var(--shadow-sm);
}

/* Secondary — brand outline */
.btn--secondary {
  background-color: #ffffff;
  color: var(--color-brand);
  border-color: var(--color-brand);
}

.btn--secondary:hover:not(:disabled) {
  background-color: var(--color-brand-light);
}

/* Ghost — muted */
.btn--ghost {
  background-color: transparent;
  color: var(--color-text-muted);
  border-color: var(--color-border);
}

.btn--ghost:hover:not(:disabled) {
  background-color: var(--color-border);
  color: var(--color-text);
  border-color: #c1cdd9;
}


/* ============================
   11. Status Bar
   ============================ */
.status-bar {
  min-height: 1.5rem;
  font-size: 0.875rem;
  font-weight: 500;
  padding: var(--space-xs) 0;
  transition: color var(--transition-fast);
}

.status-bar--success { color: var(--color-success); }
.status-bar--error   { color: var(--color-error); }
.status-bar--info    { color: var(--color-text-muted); }


/* ============================
   12. SEO Section
   ============================ */
.seo-section {
  padding: var(--space-2xl) 0;
  border-top: 1px solid var(--color-border);
  overflow: hidden; /* clear the float from .ad-content */
}

.seo-container {
  max-width: 820px;
}

.seo-section h2 {
  font-size: 1.375rem;
  font-weight: 700;
  color: var(--color-text);
  margin-top: var(--space-xl);
  margin-bottom: var(--space-sm);
}

.seo-section h2:first-child {
  margin-top: 0;
}

.seo-section h3 {
  font-size: 1.0625rem;
  font-weight: 700;
  color: var(--color-text);
  margin-top: var(--space-lg);
  margin-bottom: var(--space-xs);
}

.seo-section p {
  color: #374151;
  margin-bottom: var(--space-md);
}

.seo-section ol {
  padding-left: 1.5rem;
  margin-bottom: var(--space-md);
  color: #374151;
}

.seo-section ol li {
  margin-bottom: var(--space-xs);
}


/* ============================
   13. Site Footer
   ============================ */
.site-footer {
  background-color: var(--color-footer-bg);
  color: #94a3b8;
  padding: var(--space-xl) 0;
}

.footer-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: var(--space-md);
}

.footer-nav {
  display: flex;
  gap: var(--space-lg);
}

.footer-link {
  color: #94a3b8;
  font-size: 0.875rem;
  transition: color var(--transition-fast);
}

.footer-link:hover {
  color: #ffffff;
  text-decoration: none;
}

.footer-copy {
  font-size: 0.875rem;
}


/* ============================
   14. Main section padding
   ============================ */
.site-main {
  padding-block: var(--space-xl);
}


/* ============================
   15. Responsive Breakpoints
   ============================ */

/* Tablet and below */
@media (max-width: 768px) {
  .editor-grid {
    grid-template-columns: 1fr;
  }

  .editor-textarea {
    height: 280px;
  }

  .ad-content {
    float: none;
    width: 100%;
    max-width: 100%;
    margin-left: 0;
    margin-block: var(--space-lg);
  }

  .ad-top {
    max-width: 100%;
  }

  .tab-btn {
    padding: var(--space-sm) var(--space-lg);
    font-size: 0.9rem;
  }

  .site-title {
    font-size: 1.5rem;
  }

  .footer-inner {
    flex-direction: column;
    align-items: flex-start;
  }
}

/* Mobile */
@media (max-width: 480px) {
  .editor-textarea {
    height: 220px;
  }

  .btn-group {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: var(--space-xs);
  }

  .btn {
    padding: 0.5rem var(--space-md);
    font-size: 0.875rem;
  }

  .tab-btn {
    padding: var(--space-sm) var(--space-md);
    font-size: 0.875rem;
  }

  .container {
    padding-inline: var(--space-md);
  }
}