/* ==========================================================================
   Google Font & Root Variables (Light Blue Minimal Theme)
   ========================================================================== */
@import url('https://fonts.googleapis.com/css2?family=Inter:wght=400;500;600;700&display=swap');

:root {
  /* Core Light Blue Palette */
  --primary: #0f172a;         /* Deep slate for text/headings */
  --primary-light: #0284c7;   /* Modern light blue accent */
  --primary-hover: #0369a1;   /* Darker blue hover state */
  --primary-subtle: #f0f9ff;  /* Soft light blue tint */
  --secondary: #334155;       /* Muted slate */
  --bg-body: #f8fafc;         /* Background canvas */
  --bg-white: #ffffff;
  --text-primary: #1e293b;
  --text-secondary: #475569;  /* Muted slate gray */
  --text-muted: #94a3b8;     /* Light grayish blue */
  --border-color: #e2e8f0;   /* Minimalist light border */

  /* Status Colors */
  --success: #0284c7;
  --success-bg: #f0f9ff;
  --warning: #0369a1;
  --warning-bg: #e0f2fe;

  /* Shadows & Radius */
  --shadow-sm: 0 1px 3px rgba(15, 23, 42, 0.05);
  --shadow-md: 0 4px 12px rgba(2, 132, 199, 0.08);
  --shadow-lg: 0 10px 25px rgba(15, 23, 42, 0.12);

  --radius-sm: 8px;
  --radius-md: 12px;
  --radius-lg: 16px;

  /* Layout Spacing */
  --container-width: 1400px;
  --sidebar-width: 320px;
  --sidebar-mobile-width: 290px;
  --space-md: 20px;
  --space-xl: 40px;

  /* Global Fonts & Transitions */
  --font-family: 'Inter', -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
  --transition: all 0.2s ease;
}

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

html {
  scroll-behavior: smooth;
  height: 100%;
}

body {
  font-family: var(--font-family);
  background: var(--bg-body);
  color: var(--text-primary);
  line-height: 1.6;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  -webkit-font-smoothing: antialiased;
}

ul, ol {
  list-style: none;
}

/* Custom Scrollbars */
::-webkit-scrollbar {
  width: 6px;
  height: 6px;
}
::-webkit-scrollbar-track {
  background: var(--bg-body);
}
::-webkit-scrollbar-thumb {
  background: #cbd5e1;
  border-radius: 4px;
}
::-webkit-scrollbar-thumb:hover {
  background: #94a3b8;
}

/* ==========================================================================
   Header & Navigation Bar (Centered Responsive Grid)
   ========================================================================== */
#header {
  background: var(--bg-white);
  border-bottom: 1px solid var(--border-color);
  width: 100%;
  position: sticky;
  top: 0;
  z-index: 100;
  box-shadow: var(--shadow-sm);
}

.main-header {
  max-width: var(--container-width);
  margin: 0 auto;
  padding: 0.85rem 1.5rem;
  display: grid;
  grid-template-columns: 1fr auto 1fr; /* Left, Center, Right layout */
  align-items: center;
  width: 100%;
}

/* Left Link ("Main Page") */
.main-header > a:not(.logo) {
  justify-self: start;
  color: var(--text-secondary);
  text-decoration: none;
  font-weight: 500;
  font-size: 0.9rem;
  transition: var(--transition);
}

.main-header > a:not(.logo):hover {
  color: var(--primary-light);
}

/* Center Logo ("Tally Prime (Basic)") */
.main-header .logo {
  grid-column: 2;
  justify-self: center;
  font-size: 1.25rem;
  font-weight: 700;
  color: var(--primary-light);
  text-decoration: none;
  letter-spacing: -0.02em;
  text-align: center;
  white-space: nowrap;
}

/* Right Toggle Button */
.nav-toggle {
  grid-column: 3;
  justify-self: end;
  display: none; /* Hidden on Desktop */
  background: transparent;
  border: 1px solid var(--border-color);
  color: var(--text-secondary);
  padding: 0.4rem 0.75rem;
  border-radius: var(--radius-sm);
  cursor: pointer;
  font-size: 1.1rem;
  transition: var(--transition);
}

.nav-toggle:hover {
  background-color: var(--primary-subtle);
  color: var(--primary-light);
  border-color: #bae6fd;
}

/* ==========================================================================
   Grid Parent Container Layout
   ========================================================================== */
.parent-container {
  max-width: var(--container-width);
  margin: 20px auto;
  padding: 0 var(--space-md);
  display: grid;
  grid-template-columns: var(--sidebar-width) minmax(0, 1fr);
  gap: var(--space-md);
  align-items: start;
  flex: 1;
  width: 100%;
}

/* ==========================================================================
   Sidebar Accordions (<details> / <summary>)
   ========================================================================== */
#sidebar {
  display: flex;
  flex-direction: column;
  gap: 12px;
  width: 100%;
}

details {
  display: block;
  background: var(--bg-white);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  transition: border-color 0.2s ease, box-shadow 0.2s ease;
  flex-shrink: 0;
  overflow: hidden;
}

details:hover {
  border-color: #93c5fd;
  box-shadow: var(--shadow-sm);
}

details summary {
  list-style: none;
  cursor: pointer;
  padding: 12px 16px;
  font-size: 0.92rem;
  font-weight: 600;
  color: var(--primary);
  user-select: none;
  outline: none;
  display: flex;
  align-items: center;
  justify-content: space-between;
  line-height: 1.4;
  gap: 10px;
  min-height: 48px;
  background-color: var(--bg-white);
}

details summary::-webkit-details-marker {
  display: none;
}

details summary::after {
  content: "+";
  font-size: 1.1rem;
  font-weight: 400;
  color: var(--primary-light);
  flex-shrink: 0;
}

details[open] {
  border-color: #bae6fd;
  box-shadow: var(--shadow-md);
}

details[open] summary::after {
  content: "−";
}

details[open] summary {
  background-color: var(--primary-subtle);
  border-bottom: 1px solid var(--border-color);
  color: var(--primary-hover);
}

details ul {
  display: block;
  padding: 8px 10px 12px 10px;
  margin: 0;
  background-color: var(--bg-white);
}

details li {
  margin-bottom: 2px;
}

details a {
  text-decoration: none;
  color: var(--text-secondary);
  font-weight: 500;
  font-size: 0.88rem;
  transition: var(--transition);
  display: block;
  padding: 6px 10px;
  border-radius: var(--radius-sm);
  line-height: 1.4;
}

details a:hover {
  color: var(--primary-light);
  background: var(--primary-subtle);
  padding-left: 14px;
}

#sidebar a.active {
  color: var(--primary-light);
  background: var(--primary-subtle);
  font-weight: 700;
  border-left: 3px solid var(--primary-light);
  border-radius: 0 var(--radius-sm) var(--radius-sm) 0;
}

/* ==========================================================================
   Main Content Block
   ========================================================================== */
main {
  width: 100%;
  min-height: 500px;
  background: var(--bg-white);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  padding: clamp(20px, 4vw, var(--space-xl));
  box-shadow: var(--shadow-sm);
  overflow-x: hidden;
}

main h1, main h2, main h3, main h4 {
  color: var(--primary);
  margin-top: 1.8rem;
  margin-bottom: 0.8rem;
  font-weight: 700;
  line-height: 1.3;
  letter-spacing: -0.01em;
}

main h1:first-child,
main h2:first-child,
main h3:first-child {
  margin-top: 0;
}

main h1 {
  font-size: clamp(1.5rem, 3vw, 2.1rem);
  border-bottom: 2px solid var(--primary-subtle);
  padding-bottom: 12px;
  color: var(--primary);
}

main h2 { font-size: clamp(1.25rem, 2.5vw, 1.55rem); }
main h3 { font-size: clamp(1.05rem, 2vw, 1.25rem); }

main p {
  margin-bottom: 1.2rem;
  color: var(--text-secondary);
}

main section ul, main section ol {
  margin: 1rem 0 1.5rem 1.5rem;
  color: var(--text-secondary);
}

main section ul { list-style: disc; }
main section ol { list-style: decimal; }

main li {
  margin-bottom: 0.4rem;
}

main blockquote {
  border-left: 4px solid var(--primary-light);
  background: var(--primary-subtle);
  padding: 14px 18px;
  margin: 20px 0;
  border-radius: 0 var(--radius-sm) var(--radius-sm) 0;
  color: var(--text-primary);
}

/* ==========================================================================
   Responsive & Mobile-Friendly Code Formatting
   ========================================================================== */

/* Inline Code */
main code {
  background: var(--primary-subtle);
  color: var(--primary-light);
  padding: 0.15em 0.4em;
  border-radius: 4px;
  font-family: Consolas, Monaco, "Andale Mono", "Ubuntu Mono", monospace;
  font-size: 0.875em;
  border: 1px solid #dbeafe;
  word-break: break-word;
  overflow-wrap: break-word;
}

/* Block Code (<pre>) */
main pre {
  background: #0f172a;
  color: #f1f5f9;
  padding: 16px 20px;
  margin: 20px 0;
  border-radius: var(--radius-md);
  border: 1px solid #334155;
  overflow-x: auto;
  -webkit-overflow-scrolling: touch;
  font-family: Consolas, Monaco, "Andale Mono", "Ubuntu Mono", monospace;
  font-size: 0.875rem;
  line-height: 1.5;
  tab-size: 2;
  white-space: pre;
  word-spacing: normal;
  word-break: normal;
  word-wrap: normal;
}

main pre code {
  background: transparent;
  color: inherit;
  padding: 0;
  border: none;
  border-radius: 0;
  font-size: inherit;
  white-space: pre;
  word-break: normal;
  overflow-wrap: normal;
}

main pre::-webkit-scrollbar {
  height: 6px;
}
main pre::-webkit-scrollbar-track {
  background: #1e293b;
  border-bottom-left-radius: var(--radius-md);
  border-bottom-right-radius: var(--radius-md);
}
main pre::-webkit-scrollbar-thumb {
  background: #475569;
  border-radius: 3px;
}
main pre::-webkit-scrollbar-thumb:hover {
  background: #64748b;
}

hr {
  border: none;
  border-top: 1px solid var(--border-color);
  margin: 2rem 0;
}

/* ==========================================================================
   Responsive Data Tables (Freezed Header Effect)
   ========================================================================== */
.table-responsive {
  overflow-x: auto;
  overflow-y: auto;
  max-height: 480px;
  -webkit-overflow-scrolling: touch;
  width: 100%;
  margin: 20px 0;
  border-radius: var(--radius-md);
  border: 1px solid var(--border-color);
}

main table {
  width: 100%;
  min-width: 600px;
  border-collapse: collapse;
  border-spacing: 0;
  border: 1px solid;
}

main th {
  position: sticky;
  top: 0;
  z-index: 10;
  background-color: #f1f5f9;
  color: var(--primary);
  padding: 12px 14px;
  text-align: left;
  font-weight: 600;
  border-bottom: 2px solid var(--border-color);
  box-shadow: 0 1px 2px rgba(0,0,0,0.05);
  border: 1px solid;
}

main td {
  padding: 12px 14px;
  border-bottom: 1px solid var(--border-color);
  color: var(--text-secondary);
  vertical-align: middle;
  background-color: var(--bg-white);
  border: 1px solid;
}

main tr:nth-child(even) td { background-color: #f8fafc; }
main tr:hover td { background-color: var(--primary-subtle); }

/* ==========================================================================
   Navigation, Breadcrumbs & Step Progress Controls
   ========================================================================== */
#breadcrumbs {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 8px;
  margin-top: 20px;
  font-size: 0.88rem;
  color: var(--text-muted);
}

#breadcrumbs a { 
  color: var(--text-secondary); 
  text-decoration: none; 
}

#breadcrumbs a:hover { 
  color: var(--primary-light); 
}

#breadcrumbs strong { 
  color: var(--primary); 
}

#topicProgress {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 8px;
  background: var(--primary-subtle);
  padding: 16px;
  border-radius: var(--radius-lg);
  margin-top: 20px;
  border: 1px solid #e0f2fe;
}

.topic-step, .step-control {
  width: 38px;
  height: 38px;
  border-radius: 50%;
  background: var(--bg-white);
  color: var(--text-secondary);
  text-decoration: none;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  font-weight: 600;
  border: 1px solid var(--border-color);
  transition: var(--transition);
  font-size: 0.88rem;
}

.topic-step:hover, .step-control:hover, .topic-step.active {
  background: var(--primary-light);
  color: var(--bg-white);
  border-color: var(--primary-light);
}

#prev-next {
  display: flex;
  justify-content: space-between;
  gap: 12px;
  margin: 20px 0;
}

#prev-next a {
  flex: 1;
  padding: 10px 16px;
  text-decoration: none;
  border-radius: var(--radius-md);
  background: var(--primary-subtle);
  color: var(--primary-light);
  font-weight: 600;
  border: 1px solid #dbeafe;
  transition: var(--transition);
  text-align: center;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 44px;
}

#prev-next a:hover { 
  background: var(--primary-light); 
  color: var(--bg-white); 
  border-color: var(--primary-light);
}

/* ==========================================================================
   Module Progress Card & Percentage Progress Bar
   ========================================================================== */
#moduleProgress {
  width: 100%;
  margin-top: 25px;
}

.module-progress-card {
  background: var(--primary-subtle);
  border: 1px solid #bae6fd;
  border-radius: var(--radius-md);
  padding: 20px;
  margin: 20px 0;
}

.module-progress-card h3 {
  margin-top: 0;
  margin-bottom: 4px;
  font-size: 1.1rem;
  color: var(--primary);
}

.module-progress-card p {
  font-size: 0.88rem;
  color: var(--text-secondary);
  margin-bottom: 12px;
}

.thin-progress-wrapper {
  position: relative;
  margin: 35px auto 20px;
  width: 100%;
}

.percentage-bar-container {
  width: 100%;
  height: 6px;
  background-color: #e2e8f0;
  border-radius: 3px;
  overflow: hidden;
}

.percentage-bar-fill {
  height: 100%;
  background-color: var(--primary-light);
  border-radius: 3px;
  transition: width 0.3s ease;
}

.progress-tooltip {
  position: absolute;
  top: -32px; 
  transform: translateX(-50%);
  background-color: var(--primary);
  color: #ffffff;
  padding: 3px 8px;
  border-radius: var(--radius-sm);
  font-size: 11px;
  font-weight: 600;
  white-space: nowrap;
  box-shadow: var(--shadow-sm);
  pointer-events: none;
  transition: left 0.3s ease;
}

.progress-tooltip::after {
  content: "";
  position: absolute;
  bottom: -4px;
  left: 50%;
  transform: translateX(-50%);
  border-width: 4px 4px 0;
  border-style: solid;
  border-color: var(--primary) transparent;
}

.module-progress-card ol {
  margin: 15px 0 0 1.2rem;
  padding: 0;
  list-style: decimal;
}

.module-progress-card li {
  margin-bottom: 8px;
  font-size: 0.9rem;
}

.module-progress-card li a {
  color: var(--text-secondary);
  text-decoration: none;
  transition: color 0.2s ease;
}

.module-progress-card li a:hover {
  color: var(--primary-light);
}

.module-progress-card li.current-topic,
.module-progress-card li.current-topic a {
  font-weight: 700;
  color: var(--primary-light);
}

/* ==========================================================================
   Footer
   ========================================================================== */
.notes-footer {
  background: var(--bg-white);
  color: var(--text-secondary);
  border-top: 1px solid var(--border-color);
  padding: 1.25rem 1rem;
  text-align: center;
  margin-top: auto;
  font-size: 0.88rem;
}

.notes-footer strong {
  color: var(--text-primary);
}

.nav-overlay { display: none; }

/* ==========================================================================
   Responsive Viewport Configurations
   ========================================================================== */

/* DESKTOP: Pane Scrolling */
@media screen and (min-width: 1024px) {
  #sidebar {
    position: sticky;
    top: 75px;
    max-height: calc(100vh - 95px);
    overflow-y: auto;
    padding-right: 4px;
  }

  main {
    max-height: calc(100vh - 95px);
    overflow-y: auto;
  }
}

@media (max-width: 992px) {
  .parent-container { 
    grid-template-columns: 280px 1fr; 
    padding: 0 12px;
  }
}

/* TABLET & MOBILE DRAWER NAVIGATION */
@media (max-width: 768px) {
  .main-header {
    padding: 0.75rem 1rem;
  }

  .nav-toggle {
    display: inline-flex;
    align-items: center;
    justify-content: center;
  }

  .parent-container { 
    grid-template-columns: 1fr; 
    margin: 16px auto; 
  }
  
  #sidebar {
    position: fixed;
    top: 0;
    left: -320px;
    width: var(--sidebar-width);
    height: 100vh;
    overflow-y: auto;
    background: var(--bg-white);
    padding: 20px 16px;
    z-index: 1000;
    transition: left 0.25s ease;
    box-shadow: var(--shadow-lg);
  }

  #sidebar.active { 
    left: 0; 
  }

  .nav-overlay {
    display: block;
    position: fixed;
    inset: 0;
    background: rgba(0, 0, 0, 0.4);
    opacity: 0;
    visibility: hidden;
    transition: opacity 0.25s ease;
    z-index: 999;
  }

  .nav-overlay.active { 
    opacity: 1; 
    visibility: visible; 
  }

  #prev-next { 
    flex-direction: column; 
  }

  main pre {
    padding: 12px 14px;
    font-size: 0.8125rem;
  }
}

/* SMALL MOBILE SCREENS */
@media (max-width: 480px) {
  .main-header .logo {
    font-size: 1.05rem;
  }

  #sidebar {
    width: var(--sidebar-mobile-width);
  }

  main {
    padding: 16px 12px;
  }

  .topic-step, .step-control {
    width: 32px;
    height: 32px;
    font-size: 0.8rem;
  }
}