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

:root {
  --bg: #121212;
  --card: #181818;
  --card-hover: #212121;
  --accent: #1DB954;
  --accent-hover: #1ed760;
  --text: #FFFFFF;
  --text-secondary: #B3B3B3;
  --text-muted: #535353;
  --border: #282828;
  --surface: #212121;
  --input-bg: #0d0d0d;
  --font: 'Inter', -apple-system, BlinkMacSystemFont, sans-serif;
  --mono: 'SF Mono', 'Fira Code', 'Cascadia Code', 'Consolas', monospace;
}

html { font-size: 16px; }
body {
  font-family: var(--font);
  background: var(--bg);
  color: var(--text);
  line-height: 1.6;
  min-height: 100vh;
}

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

code {
  font-family: var(--mono);
  background: var(--surface);
  padding: 0.1em 0.4em;
  border-radius: 4px;
  font-size: 0.875em;
  color: #F5C518;
}

/* ===== Header ===== */
.header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 1rem 2rem;
  background: var(--card);
  border-bottom: 1px solid var(--border);
  position: sticky;
  top: 0;
  z-index: 100;
}
.logo {
  font-size: 1.25rem;
  font-weight: 800;
  color: var(--accent);
  letter-spacing: -0.02em;
}
.header-nav a {
  color: var(--text-secondary);
  font-size: 0.875rem;
  font-weight: 500;
  margin-left: 1.5rem;
}
.header-nav a:hover { color: var(--text); }

/* ===== 3-Column Layout ===== */
.layout-3col {
  display: grid;
  grid-template-columns: 180px 1fr 320px;
  gap: 0;
  max-width: 1600px;
  margin: 0 auto;
  min-height: 70vh;
}

.sidebar {
  padding: 1.5rem 0.75rem;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 1.5rem;
}
.sidebar-left { border-right: 1px solid var(--border); }
.sidebar-right { border-left: 1px solid var(--border); }

.ad-slot {
  background: var(--card);
  border-radius: 8px;
  display: flex;
  align-items: center;
  justify-content: center;
  min-height: 250px;
}
.ad-160x600 { width: 160px; min-height: 600px; }
.ad-300x250 { width: 300px; min-height: 250px; }

/* ===== Main Content ===== */
.main-content {
  padding: 2rem 2rem 3rem;
}

h1 {
  font-size: 1.75rem;
  font-weight: 800;
  margin-bottom: 0.5rem;
  letter-spacing: -0.02em;
}
.subtitle {
  color: var(--text-secondary);
  font-size: 0.95rem;
  margin-bottom: 1.5rem;
}

/* ===== Toolbar ===== */
.toolbar {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 0.5rem;
  padding: 0.75rem 1rem;
  background: var(--card);
  border-radius: 10px 10px 0 0;
  border: 1px solid var(--border);
  border-bottom: none;
}
.toolbar-group {
  display: flex;
  align-items: center;
  gap: 0.375rem;
}

.btn {
  font-family: var(--font);
  font-size: 0.8125rem;
  font-weight: 600;
  padding: 0.4rem 0.85rem;
  border: 1px solid var(--border);
  border-radius: 6px;
  background: var(--surface);
  color: var(--text-secondary);
  cursor: pointer;
  transition: all 0.15s ease;
  white-space: nowrap;
  text-decoration: none;
  display: inline-flex;
  align-items: center;
  gap: 0.25rem;
}
.btn:hover {
  background: #2a2a2a;
  color: var(--text);
  border-color: #404040;
}
.btn-primary {
  background: var(--accent);
  color: #000;
  border-color: var(--accent);
}
.btn-primary:hover {
  background: var(--accent-hover);
  border-color: var(--accent-hover);
  color: #000;
}
.btn-file {
  /* styled like .btn */
}

.select-label {
  font-size: 0.8125rem;
  color: var(--text-muted);
  margin-right: 0.125rem;
}
.select {
  font-family: var(--font);
  font-size: 0.8125rem;
  padding: 0.4rem 0.5rem;
  border: 1px solid var(--border);
  border-radius: 6px;
  background: var(--surface);
  color: var(--text-secondary);
  cursor: pointer;
}

/* ===== Status Bar ===== */
.status-bar {
  padding: 0.5rem 1rem;
  font-size: 0.8125rem;
  font-family: var(--mono);
  background: var(--card);
  border-left: 1px solid var(--border);
  border-right: 1px solid var(--border);
  min-height: 1.75rem;
  color: var(--text-secondary);
}
.status-bar.error { color: #E74C3C; }
.status-bar.success { color: var(--accent); }

/* ===== Editor Panels ===== */
.editor-panels {
  display: grid;
  grid-template-columns: 1fr 1fr;
  border: 1px solid var(--border);
  border-radius: 0 0 10px 10px;
  overflow: hidden;
  min-height: 380px;
}

.panel-header {
  padding: 0.5rem 1rem;
  font-size: 0.75rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: var(--text-muted);
  background: var(--card);
  border-bottom: 1px solid var(--border);
}
.panel-input { border-right: 1px solid var(--border); }

.editor-textarea {
  width: 100%;
  height: 360px;
  padding: 1rem;
  font-family: var(--mono);
  font-size: 0.8125rem;
  line-height: 1.6;
  background: var(--input-bg);
  color: var(--text);
  border: none;
  outline: none;
  resize: vertical;
  tab-size: 2;
}
.editor-textarea::placeholder { color: var(--text-muted); }
.editor-output-ta {
  color: var(--accent);
  cursor: default;
}

/* ===== Ad Inline ===== */
.ad-inline {
  margin: 1.5rem 0 0;
}

/* ===== Content Section ===== */
.content-section {
  border-top: 1px solid var(--border);
  padding: 3rem 2rem;
}
.content-inner {
  max-width: 800px;
  margin: 0 auto;
}
.content-inner h2 {
  font-size: 1.25rem;
  font-weight: 700;
  margin: 2rem 0 0.75rem;
  letter-spacing: -0.01em;
}
.content-inner h2:first-child { margin-top: 0; }
.content-inner p {
  color: var(--text-secondary);
  font-size: 0.9375rem;
  margin-bottom: 1rem;
}

/* FAQ */
.faq { margin-top: 0.5rem; }
.faq-item {
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: 8px;
  margin-bottom: 0.75rem;
  overflow: hidden;
}
.faq-item summary {
  padding: 1rem 1.25rem;
  font-weight: 600;
  font-size: 0.9375rem;
  cursor: pointer;
  list-style: none;
  display: flex;
  align-items: center;
  gap: 0.75rem;
}
.faq-item summary::before {
  content: '+';
  font-size: 1.25rem;
  font-weight: 700;
  color: var(--accent);
  flex-shrink: 0;
  width: 1.25rem;
  text-align: center;
}
.faq-item[open] summary::before { content: '-'; }
.faq-item summary::-webkit-details-marker { display: none; }
.faq-item p {
  padding: 0 1.25rem 1rem 3rem;
  color: var(--text-secondary);
  font-size: 0.875rem;
}

/* ===== Cross-links ===== */
.cross-links {
  border-top: 1px solid var(--border);
  padding: 3rem 2rem;
  background: var(--card);
}
.cross-links h2 {
  text-align: center;
  font-size: 1.25rem;
  font-weight: 700;
  margin-bottom: 1.5rem;
}
.tools-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: 1rem;
  max-width: 800px;
  margin: 0 auto;
}
.tool-card {
  display: flex;
  flex-direction: column;
  align-items: center;
  padding: 1.5rem;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 10px;
  text-align: center;
  transition: all 0.2s ease;
  color: inherit;
}
.tool-card:hover {
  border-color: var(--accent);
  background: var(--card-hover);
  transform: translateY(-2px);
  color: inherit;
}
.tool-icon { font-size: 2rem; margin-bottom: 0.5rem; }
.tool-name {
  font-weight: 600;
  font-size: 0.9375rem;
  color: var(--text);
  margin-bottom: 0.25rem;
}
.tool-desc {
  font-size: 0.8125rem;
  color: var(--text-muted);
}

/* ===== Footer ===== */
.footer {
  border-top: 1px solid var(--border);
  padding: 2rem;
  text-align: center;
}
.footer-inner { max-width: 800px; margin: 0 auto; }
.footer-links {
  display: flex;
  justify-content: center;
  gap: 1.5rem;
  margin-bottom: 1rem;
}
.footer-links a {
  color: var(--text-secondary);
  font-size: 0.875rem;
  font-weight: 500;
}
.footer-links a:hover { color: var(--text); }
.footer-copy {
  font-size: 0.75rem;
  color: var(--text-muted);
}

/* ===== Utility ===== */
.mobile-only { display: none; }

/* ===== Responsive ===== */
@media (max-width: 1100px) {
  .layout-3col {
    grid-template-columns: 1fr;
  }
  .sidebar { display: none; }
  .mobile-only { display: block; }
  .main-content { padding: 1.5rem 1rem 2rem; }
}

@media (max-width: 768px) {
  .header { padding: 0.75rem 1rem; }
  h1 { font-size: 1.375rem; }
  .editor-panels {
    grid-template-columns: 1fr;
  }
  .panel-input { border-right: none; border-bottom: 1px solid var(--border); }
  .editor-textarea { height: 240px; }
  .toolbar {
    gap: 0.375rem;
    padding: 0.5rem 0.75rem;
  }
  .btn { padding: 0.35rem 0.6rem; font-size: 0.75rem; }
  .content-section { padding: 2rem 1rem; }
  .cross-links { padding: 2rem 1rem; }
}

@media (max-width: 480px) {
  .toolbar-group { flex-wrap: wrap; }
  .editor-textarea { height: 200px; font-size: 0.75rem; }
}