/* ===== 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;
  --danger: #e74c3c;
  --danger-hover: #c0392b;
  --font: 'Inter', -apple-system, BlinkMacSystemFont, sans-serif;
}

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); }

/* ===== 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 {
  display: flex;
  align-items: center;
  gap: 1rem;
}
.header-nav a {
  color: var(--text-secondary);
  font-size: 0.875rem;
  font-weight: 500;
}
.header-nav a:hover { color: var(--text); }
.theme-toggle {
  background: none;
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 0.4rem 0.6rem;
  cursor: pointer;
  font-size: 1rem;
  line-height: 1;
}

/* ===== 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: 1rem;
  margin-bottom: 1.5rem;
}

/* ===== Privacy Badge ===== */
.privacy-badge {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  background: rgba(29, 185, 84, 0.1);
  border: 1px solid rgba(29, 185, 84, 0.3);
  border-radius: 8px;
  padding: 0.6rem 1rem;
  font-size: 0.85rem;
  color: var(--accent);
  font-weight: 500;
  margin-bottom: 1.5rem;
}
.privacy-icon { font-size: 1.1rem; }

/* ===== Drop Zone ===== */
.drop-zone {
  border: 2px dashed var(--border);
  border-radius: 12px;
  padding: 3rem 2rem;
  text-align: center;
  cursor: pointer;
  transition: border-color 0.2s, background 0.2s;
  margin-bottom: 1.5rem;
}
.drop-zone:hover,
.drop-zone.drag-over {
  border-color: var(--accent);
  background: rgba(29, 185, 84, 0.05);
}
.drop-icon { font-size: 2.5rem; display: block; margin-bottom: 0.75rem; }
.drop-text { font-size: 1rem; color: var(--text-secondary); }
.drop-link {
  color: var(--accent);
  cursor: pointer;
  font-weight: 600;
  text-decoration: underline;
}
.drop-hint { font-size: 0.8rem; color: var(--text-muted); margin-top: 0.5rem; }

/* ===== Controls ===== */
.controls {
  background: var(--card);
  border-radius: 12px;
  padding: 1.25rem;
  margin-bottom: 1.5rem;
  border: 1px solid var(--border);
}
.control-row {
  display: flex;
  flex-wrap: wrap;
  gap: 1rem;
  margin-bottom: 1rem;
  align-items: flex-end;
}
.control-row:last-child { margin-bottom: 0; }
.control-group {
  display: flex;
  flex-direction: column;
  gap: 0.35rem;
  min-width: 140px;
}
.control-group label {
  font-size: 0.8rem;
  color: var(--text-secondary);
  font-weight: 500;
}
.control-check {
  flex-direction: row;
  align-items: center;
  padding-bottom: 0.3rem;
}
.control-check label {
  display: flex;
  align-items: center;
  gap: 0.4rem;
  font-size: 0.85rem;
  cursor: pointer;
}

.slider {
  -webkit-appearance: none;
  appearance: none;
  width: 100%;
  height: 6px;
  border-radius: 3px;
  background: var(--surface);
  outline: none;
}
.slider::-webkit-slider-thumb {
  -webkit-appearance: none;
  appearance: none;
  width: 18px;
  height: 18px;
  border-radius: 50%;
  background: var(--accent);
  cursor: pointer;
}
.slider::-moz-range-thumb {
  width: 18px;
  height: 18px;
  border-radius: 50%;
  background: var(--accent);
  cursor: pointer;
  border: none;
}

.select, .input-num {
  background: var(--input-bg);
  border: 1px solid var(--border);
  color: var(--text);
  border-radius: 6px;
  padding: 0.5rem 0.75rem;
  font-size: 0.85rem;
  font-family: var(--font);
}
.input-num { width: 120px; }
.select:focus, .input-num:focus {
  outline: none;
  border-color: var(--accent);
}

.control-actions {
  display: flex;
  gap: 0.75rem;
  flex-wrap: wrap;
}

/* ===== Buttons ===== */
.btn {
  padding: 0.6rem 1.25rem;
  border-radius: 8px;
  border: 1px solid var(--border);
  background: var(--surface);
  color: var(--text);
  font-family: var(--font);
  font-size: 0.85rem;
  font-weight: 600;
  cursor: pointer;
  transition: background 0.15s, border-color 0.15s;
}
.btn:hover { background: var(--card-hover); border-color: var(--text-muted); }
.btn-primary {
  background: var(--accent);
  color: #000;
  border-color: var(--accent);
}
.btn-primary:hover {
  background: var(--accent-hover);
  border-color: var(--accent-hover);
}
.btn-secondary {
  background: transparent;
  border-color: var(--accent);
  color: var(--accent);
}
.btn-secondary:hover {
  background: rgba(29, 185, 84, 0.1);
}
.btn-danger {
  background: transparent;
  border-color: var(--danger);
  color: var(--danger);
}
.btn-danger:hover {
  background: rgba(231, 76, 60, 0.1);
}
.btn-sm {
  padding: 0.4rem 0.8rem;
  font-size: 0.8rem;
}

/* ===== Progress Bar ===== */
.progress-bar {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  margin-bottom: 1.5rem;
}
.progress-track {
  flex: 1;
  height: 8px;
  background: var(--surface);
  border-radius: 4px;
  overflow: hidden;
}
.progress-fill {
  height: 100%;
  background: var(--accent);
  border-radius: 4px;
  width: 0%;
  transition: width 0.3s;
}
.progress-text {
  font-size: 0.8rem;
  color: var(--text-secondary);
  font-weight: 600;
  min-width: 3rem;
  text-align: right;
}

/* ===== Results ===== */
.results {
  display: flex;
  flex-direction: column;
  gap: 1.25rem;
}

.result-card {
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: 12px;
  overflow: hidden;
}
.result-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0.75rem 1rem;
  border-bottom: 1px solid var(--border);
  flex-wrap: wrap;
  gap: 0.5rem;
}
.result-filename {
  font-size: 0.85rem;
  font-weight: 600;
  color: var(--text);
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
  max-width: 300px;
}
.result-stats {
  display: flex;
  align-items: center;
  gap: 1rem;
  font-size: 0.8rem;
  color: var(--text-secondary);
}
.result-savings {
  color: var(--accent);
  font-weight: 700;
}
.result-savings.negative {
  color: var(--danger);
}
.result-preview {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 1px;
  background: var(--border);
}
.preview-pane {
  background: var(--card);
  padding: 0.75rem;
  text-align: center;
}
.preview-label {
  font-size: 0.7rem;
  color: var(--text-muted);
  text-transform: uppercase;
  letter-spacing: 0.05em;
  margin-bottom: 0.5rem;
  font-weight: 600;
}
.preview-pane img {
  max-width: 100%;
  max-height: 200px;
  object-fit: contain;
  border-radius: 4px;
  background: repeating-conic-gradient(#222 0% 25%, #1a1a1a 0% 50%) 50% / 16px 16px;
}
.result-actions {
  padding: 0.75rem 1rem;
  border-top: 1px solid var(--border);
  display: flex;
  gap: 0.5rem;
}

/* ===== Utility ===== */
.hidden { display: none !important; }

/* ===== 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: 0.95rem;
  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;
  cursor: pointer;
  font-weight: 600;
  font-size: 0.95rem;
  list-style: none;
  display: flex;
  align-items: center;
  gap: 0.5rem;
}
.faq-item summary::before { content: "+"; font-weight: 700; color: var(--accent); min-width: 1rem; }
.faq-item[open] summary::before { content: "-"; }
.faq-item summary::-webkit-details-marker { display: none; }
.faq-item p {
  padding: 0 1.25rem 1rem;
  color: var(--text-secondary);
  font-size: 0.9rem;
}

/* ===== Cross-links ===== */
.cross-links {
  border-top: 1px solid var(--border);
  padding: 3rem 2rem;
}
.tools-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: 1rem;
  margin-top: 1rem;
}
.tool-card {
  display: flex;
  flex-direction: column;
  gap: 0.25rem;
  padding: 1.25rem;
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: 10px;
  transition: border-color 0.2s, background 0.2s;
}
.tool-card:hover { border-color: var(--accent); background: var(--card-hover); }
.tool-icon { font-size: 1.5rem; margin-bottom: 0.25rem; }
.tool-name { font-weight: 700; font-size: 0.95rem; color: var(--text); }
.tool-desc { font-size: 0.8rem; color: var(--text-secondary); }

/* ===== 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: 0.85rem; }
.footer-links a:hover { color: var(--text); }
.footer-copy { color: var(--text-muted); font-size: 0.8rem; }

/* ===== Mobile Ads ===== */
.mobile-only { display: none; }
.ad-inline {
  padding: 1rem 2rem;
  text-align: center;
}

/* ===== Responsive ===== */
@media (max-width: 1024px) {
  .layout-3col {
    grid-template-columns: 1fr;
  }
  .sidebar { display: none; }
  .mobile-only { display: block; }
}

@media (max-width: 600px) {
  .header { padding: 0.75rem 1rem; }
  .main-content { padding: 1.25rem 1rem 2rem; }
  h1 { font-size: 1.35rem; }
  .drop-zone { padding: 2rem 1rem; }
  .control-row { flex-direction: column; }
  .input-num { width: 100%; }
  .result-preview { grid-template-columns: 1fr; }
  .result-filename { max-width: 180px; }
  .result-stats { flex-wrap: wrap; }
  .content-section, .cross-links { padding: 2rem 1rem; }
}

/* ===== Light Theme ===== */
body.light-theme {
  --bg: #f5f5f5;
  --card: #ffffff;
  --card-hover: #f0f0f0;
  --text: #1a1a1a;
  --text-secondary: #555555;
  --text-muted: #999999;
  --border: #e0e0e0;
  --surface: #eeeeee;
  --input-bg: #ffffff;
}