/* Power Query M Master Course - Ultra-Premium Modern Light Theme (CSS Grid Layout) */
:root {
  /* Premium Light Theme Defaults */
  --bg-primary: #f8fafc;
  --bg-secondary: #ffffff;
  --bg-card: #ffffff;
  --bg-hover: #f1f5f9;
  --bg-subtle: #f8fafc;
  --border-color: #e2e8f0;
  --border-subtle: #edf2f7;
  --border-focus: #10b981;
  --border-glow: rgba(16, 185, 129, 0.25);
  --text-primary: #0f172a;
  --text-secondary: #334155;
  --text-muted: #64748b;
  --accent-green: #059669;
  --accent-green-hover: #047857;
  --accent-green-light: #ecfdf5;
  --accent-cyan: #0284c7;
  --accent-blue: #2563eb;
  --accent-purple: #7c3aed;
  --accent-amber: #d97706;
  --accent-rose: #e11d48;
  --code-bg: #0f172a;
  --code-header: #1e293b;
  --code-border: #334155;
  --code-text: #f8fafc;
  --sidebar-width: 300px;
  --header-height: 72px;
  --radius-sm: 8px;
  --radius-md: 12px;
  --radius-lg: 20px;
  --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
  --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.07), 0 2px 4px -2px rgba(0, 0, 0, 0.05);
  --shadow-lg: 0 12px 24px -4px rgba(0, 0, 0, 0.08), 0 4px 8px -2px rgba(0, 0, 0, 0.04);
  --shadow-glow: 0 8px 30px -4px rgba(5, 150, 105, 0.15);
  --font-sans: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
  --font-mono: 'Fira Code', 'Cascadia Code', 'SF Mono', monospace;
  --transition: all 0.2s cubic-bezier(0.4, 0, 0.2, 1);
}

[data-theme="dark"] {
  --bg-primary: #0b0f19;
  --bg-secondary: #111827;
  --bg-card: rgba(17, 24, 39, 0.92);
  --bg-hover: #1f2937;
  --bg-subtle: #111827;
  --border-color: rgba(255, 255, 255, 0.08);
  --border-subtle: rgba(255, 255, 255, 0.05);
  --border-focus: #10b981;
  --border-glow: rgba(16, 185, 129, 0.3);
  --text-primary: #f9fafb;
  --text-secondary: #9ca3af;
  --text-muted: #6b7280;
  --accent-green: #10b981;
  --accent-green-hover: #059669;
  --accent-green-light: rgba(16, 185, 129, 0.15);
  --code-bg: #030712;
  --code-header: #0f172a;
  --code-border: #1e293b;
  --code-text: #f8fafc;
  --shadow-sm: 0 1px 3px 0 rgba(0, 0, 0, 0.4);
  --shadow-md: 0 4px 14px 0 rgba(0, 0, 0, 0.5);
  --shadow-lg: 0 12px 28px 0 rgba(0, 0, 0, 0.6);
  --shadow-glow: 0 0 25px -5px rgba(16, 185, 129, 0.3);
}

html, body {
  width: 100%;
  max-width: 100vw;
  overflow-x: hidden;
  box-sizing: border-box;
  scroll-behavior: smooth;
}

*, *:before, *:after {
  box-sizing: inherit;
}

body {
  margin: 0;
  padding: 0;
  font-family: var(--font-sans);
  background-color: var(--bg-primary);
  color: var(--text-primary);
  line-height: 1.68;
  -webkit-font-smoothing: antialiased;
}

/* Minimalist Scrollbars */
::-webkit-scrollbar {
  width: 7px;
  height: 7px;
}
::-webkit-scrollbar-track {
  background: var(--bg-primary);
}
::-webkit-scrollbar-thumb {
  background: #cbd5e1;
  border-radius: 4px;
}
::-webkit-scrollbar-thumb:hover {
  background: var(--accent-green);
}

/* Glassmorphic Fixed Navbar */
.navbar {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  height: var(--header-height);
  background: rgba(255, 255, 255, 0.92);
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  border-bottom: 1px solid var(--border-color);
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1.5rem;
  padding: 0 2rem;
  z-index: 100;
  box-shadow: var(--shadow-sm);
  transition: var(--transition);
}

[data-theme="dark"] .navbar {
  background: rgba(11, 15, 25, 0.9);
}

.brand-container {
  display: flex;
  align-items: center;
  gap: 1rem;
  flex-shrink: 0;
}

.brand {
  display: flex;
  align-items: center;
  gap: 12px;
  text-decoration: none;
  color: inherit;
}

.brand-icon {
  width: 40px;
  height: 40px;
  background: linear-gradient(135deg, var(--accent-green), #0284c7);
  border-radius: 10px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 800;
  font-size: 1.3rem;
  color: #ffffff;
  box-shadow: 0 4px 12px rgba(5, 150, 105, 0.25);
}

.brand-text h1 {
  font-size: 1.12rem;
  font-weight: 800;
  letter-spacing: -0.03em;
  color: var(--text-primary);
}

.brand-text span {
  font-size: 0.725rem;
  color: var(--accent-green);
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.06em;
}

/* Modern Centered Search Container */
.search-container {
  position: relative;
  display: flex;
  align-items: center;
  flex: 1;
  max-width: 420px;
  margin: 0 auto;
}

.search-input {
  width: 100%;
  background: var(--bg-primary);
  border: 1px solid var(--border-color);
  border-radius: 24px;
  padding: 0.55rem 1.1rem 0.55rem 2.5rem;
  font-size: 0.875rem;
  color: var(--text-primary);
  transition: var(--transition);
  box-shadow: inset 0 1px 2px rgba(0, 0, 0, 0.03);
}

.search-input:focus {
  outline: none;
  border-color: var(--accent-green);
  background: var(--bg-secondary);
  box-shadow: 0 0 0 3px rgba(16, 185, 129, 0.15);
}

.search-icon-svg {
  position: absolute;
  left: 12px;
  color: var(--text-muted);
  width: 16px;
  height: 16px;
  pointer-events: none;
}

.nav-actions {
  display: flex;
  align-items: center;
  gap: 0.85rem;
  flex-shrink: 0;
}

/* Buttons */
.btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 0.55rem 1.15rem;
  border-radius: var(--radius-sm);
  font-size: 0.875rem;
  font-weight: 600;
  cursor: pointer;
  border: none;
  transition: var(--transition);
  text-decoration: none;
}

.btn-primary {
  background: linear-gradient(135deg, var(--accent-green), #047857);
  color: #ffffff;
  box-shadow: 0 3px 12px rgba(5, 150, 105, 0.28);
}

.btn-primary:hover {
  transform: translateY(-1px);
  box-shadow: 0 6px 18px rgba(5, 150, 105, 0.42);
}

.theme-toggle {
  background: var(--bg-secondary);
  border: 1px solid var(--border-color);
  color: var(--text-primary);
  width: 40px;
  height: 40px;
  border-radius: 50%;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: var(--transition);
  box-shadow: var(--shadow-sm);
}

.theme-toggle:hover {
  border-color: var(--accent-green);
  color: var(--accent-green);
  transform: rotate(15deg);
}

/* ==========================================================================
   PERMANENT PINNED SIDEBAR LAYOUT (Sidebar Never Disappears on Scroll)
   ========================================================================== */
.layout {
  display: block;
  width: 100%;
  margin-top: var(--header-height);
  min-height: calc(100vh - var(--header-height));
  position: relative;
}

/* Fixed Left Sidebar - Pinned permanently to viewport, never scrolls away */
.sidebar {
  width: var(--sidebar-width);
  height: calc(100vh - var(--header-height));
  position: fixed;
  top: var(--header-height);
  left: 0;
  background: var(--bg-secondary);
  border-right: 1px solid var(--border-color);
  overflow-y: auto;
  padding: 1.5rem 0.85rem 4rem 0.85rem;
  z-index: 80;
}

.nav-section {
  margin-bottom: 1.4rem;
}

.nav-section-title {
  font-size: 0.725rem;
  text-transform: uppercase;
  letter-spacing: 0.09em;
  font-weight: 800;
  color: var(--text-muted);
  padding: 0.35rem 0.75rem;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.nav-link {
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 0.52rem 0.8rem;
  color: var(--text-secondary);
  text-decoration: none;
  font-size: 0.86rem;
  font-weight: 500;
  border-radius: var(--radius-sm);
  transition: var(--transition);
}

.nav-link:hover {
  color: var(--text-primary);
  background: var(--bg-hover);
}

.nav-link.active {
  color: var(--accent-green);
  background: var(--accent-green-light);
  font-weight: 700;
  border-left: 3px solid var(--accent-green);
}

.nav-badge {
  font-size: 0.675rem;
  font-weight: 700;
  padding: 2px 7px;
  border-radius: 12px;
  background: var(--accent-green-light);
  color: var(--accent-green);
  margin-left: auto;
}

/* Main Content Area (Offset by sidebar width) */
.main-content {
  margin-left: var(--sidebar-width);
  width: calc(100% - var(--sidebar-width));
  min-width: 0; /* Critical: allows code blocks and tables to size safely */
  padding: 2.5rem 3.5rem 7rem 3.5rem;
  max-width: 1300px;
}

/* Hero Section */
.hero {
  background: linear-gradient(135deg, #ffffff 0%, #f0fdf4 45%, #eff6ff 100%);
  border: 1px solid #d1fae5;
  border-radius: var(--radius-lg);
  padding: 3rem 2.8rem;
  margin-bottom: 3.5rem;
  position: relative;
  overflow: hidden;
  box-shadow: var(--shadow-glow);
}

[data-theme="dark"] .hero {
  background: linear-gradient(135deg, rgba(16, 185, 129, 0.1) 0%, rgba(6, 182, 212, 0.05) 50%, transparent 100%);
  border-color: var(--border-glow);
}

.hero::after {
  content: "M";
  position: absolute;
  right: -10px;
  bottom: -40px;
  font-size: 18rem;
  font-weight: 900;
  font-family: var(--font-mono);
  color: rgba(5, 150, 105, 0.04);
  pointer-events: none;
  line-height: 1;
}

.hero-badges {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  margin-bottom: 1.2rem;
}

.badge {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 5px 12px;
  border-radius: 20px;
  font-size: 0.75rem;
  font-weight: 700;
  letter-spacing: 0.02em;
}

.badge-green { background: #ecfdf5; color: #047857; border: 1px solid #a7f3d0; }
.badge-cyan { background: #f0f9ff; color: #0369a1; border: 1px solid #bae6fd; }
.badge-purple { background: #f5f3ff; color: #6d28d9; border: 1px solid #ddd6fe; }
.badge-amber { background: #fffbeb; color: #b45309; border: 1px solid #fde68a; }

.hero-title {
  font-size: 2.8rem;
  font-weight: 800;
  letter-spacing: -0.035em;
  line-height: 1.15;
  margin-bottom: 1rem;
  color: #0f172a;
}

[data-theme="dark"] .hero-title {
  background: linear-gradient(to right, #ffffff, #94a3b8);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
}

.hero-subtitle {
  font-size: 1.15rem;
  color: var(--text-secondary);
  max-width: 820px;
  line-height: 1.65;
  margin-bottom: 2rem;
}

.hero-stats {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(130px, 1fr));
  gap: 1.5rem;
  margin-top: 2rem;
  padding-top: 2rem;
  border-top: 1px solid rgba(0, 0, 0, 0.07);
}

[data-theme="dark"] .hero-stats {
  border-top-color: var(--border-color);
}

.stat-item h3 {
  font-size: 2rem;
  font-weight: 800;
  color: var(--accent-green);
  font-family: var(--font-mono);
  letter-spacing: -0.03em;
}

.stat-item p {
  font-size: 0.825rem;
  color: var(--text-muted);
  font-weight: 600;
}

/* Sections */
.section {
  margin-bottom: 4.8rem;
  scroll-margin-top: calc(var(--header-height) + 1.5rem);
}

.section-header {
  margin-bottom: 1.8rem;
  border-bottom: 1px solid var(--border-color);
  padding-bottom: 0.9rem;
}

.section-tag {
  color: var(--accent-green);
  font-size: 0.775rem;
  font-weight: 800;
  text-transform: uppercase;
  letter-spacing: 0.09em;
}

.section-title {
  font-size: 2rem;
  font-weight: 800;
  letter-spacing: -0.025em;
  margin-top: 4px;
  color: var(--text-primary);
}

.section-desc {
  color: var(--text-secondary);
  font-size: 0.98rem;
  margin-top: 6px;
}

/* Cards & Grid */
.cards-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
  gap: 1.5rem;
  margin: 1.5rem 0;
}

.card {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  padding: 1.5rem;
  box-shadow: var(--shadow-sm);
  transition: var(--transition);
}

.card:hover {
  border-color: #cbd5e1;
  box-shadow: var(--shadow-md);
  transform: translateY(-2px);
}

.card-title {
  font-size: 1.15rem;
  font-weight: 700;
  letter-spacing: -0.015em;
  margin-bottom: 0.75rem;
  color: var(--text-primary);
}

/* Callout Boxes */
.callout {
  padding: 1.2rem 1.5rem;
  border-radius: var(--radius-md);
  margin: 1.5rem 0;
  display: flex;
  gap: 14px;
  align-items: flex-start;
  border-left: 4px solid;
  box-shadow: var(--shadow-sm);
}

.callout-info {
  background: #eff6ff;
  border-left-color: var(--accent-blue);
  border-top: 1px solid #dbeafe;
  border-right: 1px solid #dbeafe;
  border-bottom: 1px solid #dbeafe;
}

.callout-tip {
  background: #ecfdf5;
  border-left-color: var(--accent-green);
  border-top: 1px solid #d1fae5;
  border-right: 1px solid #d1fae5;
  border-bottom: 1px solid #d1fae5;
}

.callout-warning {
  background: #fffbeb;
  border-left-color: var(--accent-amber);
  border-top: 1px solid #fef3c7;
  border-right: 1px solid #fef3c7;
  border-bottom: 1px solid #fef3c7;
}

.callout-danger {
  background: #fff1f2;
  border-left-color: var(--accent-rose);
  border-top: 1px solid #ffe4e6;
  border-right: 1px solid #ffe4e6;
  border-bottom: 1px solid #ffe4e6;
}

.callout-icon-svg {
  width: 22px;
  height: 22px;
  flex-shrink: 0;
  margin-top: 2px;
}

.callout-content h4 {
  font-size: 0.95rem;
  font-weight: 700;
  margin-bottom: 4px;
  color: var(--text-primary);
}

.callout-content p {
  font-size: 0.9rem;
  color: var(--text-secondary);
}

/* Code Blocks */
.code-wrapper {
  background: var(--code-bg);
  border: 1px solid var(--code-border);
  border-radius: var(--radius-md);
  margin: 1.5rem 0;
  overflow: hidden;
  box-shadow: var(--shadow-md);
}

.code-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0.65rem 1.1rem;
  background: var(--code-header);
  border-bottom: 1px solid var(--code-border);
}

.code-lang {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  color: #34d399;
  text-transform: uppercase;
  font-weight: 700;
  letter-spacing: 0.05em;
}

.btn-copy {
  background: rgba(255, 255, 255, 0.08);
  border: 1px solid rgba(255, 255, 255, 0.15);
  color: #cbd5e1;
  padding: 4px 10px;
  border-radius: 6px;
  font-size: 0.75rem;
  font-weight: 600;
  cursor: pointer;
  display: flex;
  align-items: center;
  gap: 6px;
  transition: var(--transition);
}

.btn-copy:hover {
  background: rgba(255, 255, 255, 0.18);
  color: #ffffff;
  border-color: #34d399;
}

pre {
  margin: 0;
  padding: 1.3rem;
  overflow-x: auto;
  font-family: var(--font-mono);
  font-size: 0.88rem;
  line-height: 1.65;
  color: #e2e8f0;
}

code {
  font-family: var(--font-mono);
}

:not(pre) > code {
  background: #f1f5f9;
  color: #0f766e;
  padding: 2px 6px;
  border-radius: 4px;
  font-size: 0.875em;
  font-weight: 600;
  border: 1px solid #e2e8f0;
}

[data-theme="dark"] :not(pre) > code {
  background: rgba(255, 255, 255, 0.08);
  color: #34d399;
  border-color: transparent;
}

/* Tabs */
.tabs-container {
  margin: 1.5rem 0;
}

.tab-nav {
  display: flex;
  gap: 8px;
  border-bottom: 1px solid var(--border-color);
  padding-bottom: 8px;
  overflow-x: auto;
}

.tab-btn {
  background: transparent;
  border: none;
  color: var(--text-muted);
  padding: 8px 16px;
  border-radius: var(--radius-sm);
  font-size: 0.88rem;
  font-weight: 600;
  cursor: pointer;
  transition: var(--transition);
  white-space: nowrap;
}

.tab-btn:hover {
  color: var(--text-primary);
  background: var(--bg-hover);
}

.tab-btn.active {
  color: var(--accent-green);
  background: var(--accent-green-light);
  font-weight: 700;
}

.tab-content {
  display: none;
  padding-top: 1.5rem;
}

.tab-content.active {
  display: block;
}

/* Tables */
.table-responsive {
  overflow-x: auto;
  margin: 1.5rem 0;
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  box-shadow: var(--shadow-sm);
  background: var(--bg-secondary);
}

table {
  width: 100%;
  border-collapse: collapse;
  font-size: 0.88rem;
  text-align: left;
}

th {
  background: var(--bg-subtle);
  padding: 12px 16px;
  font-weight: 700;
  color: var(--text-primary);
  border-bottom: 1px solid var(--border-color);
}

td {
  padding: 12px 16px;
  border-bottom: 1px solid var(--border-color);
  color: var(--text-secondary);
}

tr:last-child td {
  border-bottom: none;
}

tr:hover td {
  background: rgba(0, 0, 0, 0.015);
}

/* Accordions */
.accordion {
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  margin-bottom: 0.8rem;
  overflow: hidden;
  background: var(--bg-card);
  box-shadow: var(--shadow-sm);
  transition: var(--transition);
}

.accordion:hover {
  border-color: #cbd5e1;
}

.accordion-header {
  padding: 1rem 1.3rem;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: space-between;
  font-weight: 600;
  font-size: 0.93rem;
  transition: var(--transition);
  color: var(--text-primary);
}

.accordion-header:hover {
  background: var(--bg-hover);
}

.accordion-icon-svg {
  width: 14px;
  height: 14px;
  color: var(--text-muted);
  transition: transform 0.25s ease;
  flex-shrink: 0;
}

.accordion.open .accordion-icon-svg {
  transform: rotate(180deg);
  color: var(--accent-green);
}

.accordion-body {
  display: none;
  padding: 1.3rem;
  border-top: 1px solid var(--border-color);
  background: var(--bg-subtle);
}

.accordion.open .accordion-body {
  display: block;
}

/* Day Plan Checkboxes */
.day-card {
  display: flex;
  gap: 15px;
  padding: 1.25rem;
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  margin-bottom: 0.8rem;
  background: var(--bg-card);
  box-shadow: var(--shadow-sm);
  transition: var(--transition);
}

.day-card:hover {
  border-color: #cbd5e1;
  box-shadow: var(--shadow-md);
}

.day-checkbox {
  margin-top: 4px;
  width: 19px;
  height: 19px;
  accent-color: var(--accent-green);
  cursor: pointer;
}

.day-details {
  flex: 1;
}

.day-header {
  display: flex;
  align-items: center;
  gap: 10px;
  margin-bottom: 5px;
}

.day-num {
  font-size: 0.725rem;
  font-weight: 800;
  padding: 3px 8px;
  background: var(--accent-green-light);
  color: var(--accent-green);
  border-radius: 6px;
}

.day-title {
  font-size: 1.02rem;
  font-weight: 700;
  color: var(--text-primary);
}

.day-theory {
  font-size: 0.88rem;
  color: var(--text-secondary);
  margin-bottom: 8px;
}

.day-task {
  font-size: 0.825rem;
  font-weight: 600;
  color: #0369a1;
  background: #f0f9ff;
  border: 1px solid #e0f2fe;
  padding: 5px 11px;
  border-radius: var(--radius-sm);
  display: inline-block;
}

/* Filter Tags */
.filter-container {
  display: flex;
  gap: 8px;
  flex-wrap: wrap;
  margin: 1.5rem 0;
}

.filter-btn {
  padding: 6px 15px;
  border-radius: 20px;
  border: 1px solid var(--border-color);
  background: var(--bg-secondary);
  color: var(--text-secondary);
  font-size: 0.825rem;
  cursor: pointer;
  font-weight: 600;
  transition: var(--transition);
  box-shadow: var(--shadow-sm);
}

.filter-btn.active, .filter-btn:hover {
  background: var(--accent-green);
  color: #ffffff;
  border-color: var(--accent-green);
  box-shadow: 0 3px 10px rgba(5, 150, 105, 0.25);
}

/* Mobile Toggle */
.mobile-toggle {
  display: none;
  background: transparent;
  border: none;
  color: var(--text-primary);
  font-size: 1.4rem;
  cursor: pointer;
}

@media (max-width: 992px) {
  .layout {
    display: block;
  }
  .sidebar {
    position: fixed;
    top: var(--header-height);
    left: 0;
    width: var(--sidebar-width);
    height: calc(100vh - var(--header-height));
    transform: translateX(-100%);
    transition: transform 0.28s cubic-bezier(0.4, 0, 0.2, 1);
    z-index: 95;
    box-shadow: 4px 0 25px rgba(0, 0, 0, 0.15);
  }
  .sidebar.open {
    transform: translateX(0);
  }
  .main-content {
    margin-left: 0;
    width: 100%;
    padding: 1.8rem 1.2rem 5rem 1.2rem;
  }
  .mobile-toggle {
    display: block;
  }
  .hero {
    padding: 2rem 1.4rem;
  }
  .hero-title {
    font-size: 2rem;
  }
  .search-container {
    max-width: 220px;
  }
}