/* ============================================================
   ⚡ QuickConverter — Replace PDF Pages Tool
   ------------------------------------------------------------
   Visual Psychology:
     • Blue  = Trust / Professional (Primary Action)
     • Red   = Warning / Removal (Clear Actions)
     • Green = Success / Completion (Results)
   ============================================================ */

body {
  font-family: "Inter", "Segoe UI", Roboto, sans-serif;
  background: linear-gradient(135deg, #eef6ff, #ffffff);
  color: #1e293b;
  margin: 0;
  padding: 0;
  transition: background 0.4s, color 0.4s;
}

.dark-mode {
  background: linear-gradient(135deg, #0f172a, #1e293b);
  color: #e2e8f0;
}

/* ========================= Header ========================= */
header.glass-header {
  backdrop-filter: blur(10px);
  background: rgba(255, 255, 255, 0.85);
  border-bottom: 1px solid rgba(0, 0, 0, 0.08);
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 12px 30px;
  position: sticky;
  top: 0;
  z-index: 100;
}

header.glass-header .logo span {
  font-size: 1.4rem;
  font-weight: 700;
  color: #0078d7;
}

.dark-mode header.glass-header {
  background: rgba(30, 41, 59, 0.85);
  border-color: rgba(255, 255, 255, 0.1);
}

/* ========================= Hero Section ========================= */
.hero {
  text-align: center;
  padding: 70px 20px 30px;
  color: #fff;
  border-radius: 0 0 40px 40px;
  box-shadow: 0 8px 20px rgba(0, 120, 215, 0.3);
  background: linear-gradient(135deg, #0078d7, #00b4d8);
}

.hero h1 {
  font-size: 2.4rem;
  margin-bottom: 8px;
}

.hero p {
  color: #e0f7ff;
  font-size: 1.1rem;
}

/* ========================= Tool Container ========================= */
.tool-container {
  max-width: 900px; /* Wider to accommodate dual panels side-by-side */
  margin: 40px auto;
  background: #ffffff;
  padding: 40px;
  border-radius: 16px;
  box-shadow: 0 10px 25px rgba(0, 0, 0, 0.05);
  text-align: center;
  transition: all 0.4s;
}

.dark-mode .tool-container {
  background: #1e293b;
}

/* ========================= Drop Zone ========================= */
.drop-zone {
  border: 3px dashed #0078d7;
  border-radius: 12px;
  padding: 50px;
  color: #475569;
  background: #f9fbfd;
  cursor: pointer;
  transition: all 0.3s ease;
}

.drop-zone:hover {
  background: #eaf5ff;
}

.dark-mode .drop-zone {
  background: #0f172a;
  border-color: #38bdf8;
  color: #cbd5e1;
}

/* ========================= PDF Panels (Dual View) ========================= */
.pdf-panels {
  display: none;
  grid-template-columns: 1fr 1fr;
  gap: 25px;
  margin-top: 25px;
}

.pdf-panels.active {
  display: grid;
}

.pdf-panels h3 {
  font-size: 1.1rem;
  margin-bottom: 12px;
  color: #0078d7;
}

/* ========================= Pages Grid ========================= */
.pagesContainer {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(140px, 1fr));
  gap: 15px;
  justify-items: center;
  background: #f1f5f9;
  padding: 15px;
  border-radius: 12px;
  max-height: 500px;
  overflow-y: auto;
}

.dark-mode .pagesContainer {
  background: #0f172a;
}

.page-thumb {
  position: relative;
  background: #fff;
  padding: 8px;
  border-radius: 8px;
  border: 2px solid transparent;
  box-shadow: 0 4px 6px rgba(0,0,0,0.05);
  cursor: pointer;
  transition: all 0.2s ease;
  width: 100%;
}

.page-thumb:hover {
  transform: translateY(-2px);
}

.dark-mode .page-thumb {
  background: #2d2d2d;
  border-color: #444;
}

/* Blue selection for Replacement tool */
.page-thumb.selected {
  border-color: #0078d7;
  box-shadow: 0 0 12px rgba(0, 120, 215, 0.3);
}

.page-thumb canvas {
  max-width: 100%;
  height: auto;
  border-radius: 4px;
}

.page-num-label {
  position: absolute;
  bottom: 6px;
  right: 6px;
  background: rgba(0, 0, 0, 0.7);
  color: #fff;
  font-size: 0.7rem;
  padding: 2px 6px;
  border-radius: 4px;
}

/* ========================= Buttons ========================= */
.btn-primary {
  background: linear-gradient(90deg, #0078d7, #00a6ff);
  color: #fff;
  border: none;
  padding: 14px 32px;
  border-radius: 10px;
  font-weight: 600;
  cursor: pointer;
  box-shadow: 0 4px 12px rgba(0,120,215,0.3);
  transition: all 0.3s;
}

.btn-primary:hover:not(:disabled) {
  background: linear-gradient(90deg, #005fa3, #0084d1);
  transform: translateY(-2px);
}

.btn-primary:disabled {
  opacity: 0.5;
  cursor: not-allowed;
  box-shadow: none;
}

.btn-outline-danger {
  background: #fff;
  border: 2px solid #dc2626;
  color: #dc2626;
  font-weight: 600;
  padding: 12px 24px;
  border-radius: 8px;
  cursor: pointer;
  transition: 0.3s;
}

.btn-outline-danger:hover {
  background: #fee2e2;
  transform: translateY(-2px);
}

/* ========================= Related Tools ========================= */
.related-tools {
  max-width: 900px;
  margin: 60px auto;
  text-align: center;
  background: linear-gradient(135deg, #f9fafb, #f0f9ff);
  border-radius: 14px;
  padding: 40px 30px;
  box-shadow: 0 8px 25px rgba(0, 0, 0, 0.05);
}

.dark-mode .related-tools {
  background: linear-gradient(135deg, #1e293b, #0f172a);
}

.related-grid {
  display: flex;
  justify-content: center;
  flex-wrap: wrap;
  gap: 15px;
}

.related-grid a {
  background: linear-gradient(90deg, #0078d7, #00a2ff);
  color: #fff;
  text-decoration: none;
  padding: 12px 24px;
  border-radius: 8px;
  font-weight: 600;
  transition: all 0.3s;
}

.related-grid a:hover {
  background: linear-gradient(90deg, #005fa3, #0078d7);
  transform: translateY(-3px);
}

/* ========================= Footer ========================= */
footer {
  text-align: center;
  padding: 35px 10px;
  margin-top: 60px;
  color: #64748b;
  font-size: 1rem;
  border-top: 1px solid #e2e8f0;
  background: linear-gradient(180deg, #f9fafb, #f1f5f9);
}

.dark-mode footer {
  background: #0f172a;
  border-color: #334155;
}

footer strong {
  color: #0078d7;
  font-weight: 700;
}

/* ========================= Responsive ========================= */
@media (max-width: 850px) {
  .pdf-panels.active {
    grid-template-columns: 1fr;
  }
  .tool-container {
    padding: 20px;
    margin: 20px;
  }
}