/* =============================================================================
   CP Mastery Hub — Professional Educational Platform Styling
   Inspired by Apna College, Striver A2Z, Linear, and Modern SaaS Dark Aesthetics
   ============================================================================= */

@import url('https://fonts.googleapis.com/css2?family=Inter:wght@300;400;500;600;700;800&family=JetBrains+Mono:wght@400;500;600;700&family=Plus+Jakarta+Sans:wght@400;500;600;700;800&display=swap');

:root {
  --font-sans: 'Plus Jakarta Sans', 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
  --font-mono: 'JetBrains Mono', 'Fira Code', monospace;

  /* Refined Modern Dark Theme Palette */
  --bg-app: #090d16;
  --bg-surface: #0f172a;
  --bg-card: #131c2e;
  --bg-card-hover: #172338;
  --bg-elevated: #1e293b;
  
  --border-subtle: rgba(255, 255, 255, 0.07);
  --border-medium: rgba(255, 255, 255, 0.12);
  --border-focus: #6366f1;

  --accent-primary: #6366f1; /* Royal Indigo */
  --accent-primary-hover: #4f46e5;
  --accent-secondary: #8b5cf6; /* Violet */
  --accent-emerald: #10b981;
  --accent-amber: #f59e0b;
  --accent-rose: #f43f5e;
  --accent-sky: #0ea5e9;

  --text-main: #f8fafc;
  --text-muted: #94a3b8;
  --text-subtle: #64748b;
}

* {
  box-sizing: border-box;
}

body {
  font-family: var(--font-sans);
  background-color: var(--bg-app);
  color: var(--text-main);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  text-rendering: optimizeLegibility;
  overflow-x: hidden;
  background-image: radial-gradient(circle at 50% 0%, rgba(99, 102, 241, 0.05) 0%, transparent 60%);
}

code, pre, .font-mono {
  font-family: var(--font-mono) !important;
}

/* Custom Scrollbars */
::-webkit-scrollbar {
  width: 6px;
  height: 6px;
}
::-webkit-scrollbar-track {
  background: var(--bg-app);
}
::-webkit-scrollbar-thumb {
  background: #1e293b;
  border-radius: 6px;
}
::-webkit-scrollbar-thumb:hover {
  background: #334155;
}

/* Professional Surface Cards */
.pro-card {
  background-color: var(--bg-card);
  border: 1px solid var(--border-subtle);
  border-radius: 1rem;
  transition: border-color 0.2s ease, box-shadow 0.2s ease, transform 0.2s ease;
}
.pro-card:hover {
  border-color: var(--border-medium);
}

.pro-card-interactive {
  background-color: var(--bg-card);
  border: 1px solid var(--border-subtle);
  border-radius: 1rem;
  transition: all 0.2s ease;
}
.pro-card-interactive:hover {
  border-color: rgba(99, 102, 241, 0.4);
  background-color: var(--bg-card-hover);
  box-shadow: 0 10px 25px -5px rgba(0, 0, 0, 0.3);
}

.pro-header-glass {
  background: rgba(11, 15, 25, 0.85);
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  border-bottom: 1px solid var(--border-subtle);
}

/* Custom Checkbox */
.custom-check {
  appearance: none;
  -webkit-appearance: none;
  width: 1.15rem;
  height: 1.15rem;
  border: 1.5px solid #475569;
  border-radius: 0.35rem;
  background-color: #0f172a;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  transition: all 0.15s ease;
  flex-shrink: 0;
}
.custom-check:checked {
  background-color: #10b981;
  border-color: #10b981;
}
.custom-check:checked::after {
  content: '✓';
  color: #022c22;
  font-size: 0.8rem;
  font-weight: 800;
}
.custom-check:focus {
  outline: none;
  box-shadow: 0 0 0 2px rgba(16, 185, 129, 0.3);
}

/* Star Bookmark Button */
.star-btn {
  color: #64748b;
  transition: all 0.15s ease;
}
.star-btn:hover {
  color: #f59e0b;
  transform: scale(1.1);
}
.star-btn.starred {
  color: #fbbf24;
  fill: #fbbf24;
}

/* Visualizer Bars */
.viz-bar {
  transition: all 0.2s cubic-bezier(0.4, 0, 0.2, 1);
  border-radius: 6px 6px 2px 2px;
}
.viz-bar.active {
  background: linear-gradient(180deg, #f43f5e 0%, #e11d48 100%) !important;
  box-shadow: 0 0 16px rgba(244, 63, 94, 0.5);
  transform: scaleY(1.03);
}
.viz-bar.comparing {
  background: linear-gradient(180deg, #f59e0b 0%, #d97706 100%) !important;
  box-shadow: 0 0 16px rgba(245, 158, 11, 0.5);
}
.viz-bar.sorted {
  background: linear-gradient(180deg, #10b981 0%, #059669 100%) !important;
  box-shadow: 0 0 12px rgba(16, 185, 129, 0.4);
}
.viz-bar.pointer-left {
  outline: 2px solid #6366f1;
}
.viz-bar.pointer-right {
  outline: 2px solid #ec4899;
}

/* Subtle Toast */
#toast-notification {
  transition: transform 0.3s cubic-bezier(0.16, 1, 0.3, 1), opacity 0.3s ease;
}

/* Markdown typography inside concept cards */
.concept-markdown h3 {
  font-size: 1.05rem;
  font-weight: 700;
  color: #f8fafc;
  margin-top: 1rem;
  margin-bottom: 0.5rem;
}
.concept-markdown p {
  font-size: 0.875rem;
  color: #cbd5e1;
  line-height: 1.6;
  margin-bottom: 0.75rem;
}
.concept-markdown ul {
  list-style-type: disc;
  padding-left: 1.25rem;
  margin-bottom: 0.75rem;
}
.concept-markdown li {
  font-size: 0.85rem;
  color: #cbd5e1;
  margin-bottom: 0.35rem;
  line-height: 1.5;
}
.concept-markdown strong {
  color: #f1f5f9;
  font-weight: 600;
}
.concept-markdown code {
  background-color: #1e293b;
  color: #a5b4fc;
  padding: 0.15rem 0.35rem;
  border-radius: 0.25rem;
  font-size: 0.8rem;
}

/* Code block highlight */
pre.code-block {
  background-color: #090d16;
  border: 1px solid rgba(255, 255, 255, 0.08);
  border-radius: 0.75rem;
  padding: 1rem;
  font-size: 0.8rem;
  line-height: 1.5;
  overflow-x: auto;
  color: #e2e8f0;
}