/* ==========================================================================
   Java Lab Model Answers — Stylesheet
   Modern, responsive, accessible, dark/light theme ready
   ========================================================================== */

:root {
  --font-sans: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  --font-mono: "JetBrains Mono", Consolas, "Fira Code", "Courier New", monospace;

  /* Color Palette - Dark Mode Default */
  --bg-primary: #0b0f19;
  --bg-secondary: #111827;
  --bg-card: #161f30;
  --bg-card-hover: #1c273e;
  --bg-muted: #1e293b;
  --bg-input: #0f172a;
  
  --border-color: #27354f;
  --border-subtle: #1e293b;
  --border-focus: #3b82f6;

  --text-primary: #f8fafc;
  --text-secondary: #94a3b8;
  --text-muted: #64748b;
  --text-accent: #38bdf8;

  --primary: #3b82f6;
  --primary-hover: #2563eb;
  --primary-gradient: linear-gradient(135deg, #3b82f6 0%, #6366f1 100%);
  --accent-glow: rgba(59, 130, 246, 0.15);

  --badge-bg: rgba(56, 189, 248, 0.12);
  --badge-text: #38bdf8;
  --badge-border: rgba(56, 189, 248, 0.25);

  --success-bg: rgba(34, 197, 94, 0.12);
  --success-text: #4ade80;
  --success-border: rgba(34, 197, 94, 0.25);

  --warning-bg: rgba(234, 179, 8, 0.12);
  --warning-text: #facc15;
  --warning-border: rgba(234, 179, 8, 0.25);

  --code-bg: #090d16;
  --code-header-bg: #111726;
  --code-text: #e2e8f0;
  --code-border: #1e293b;

  /* Syntax Highlighting Colors */
  --syn-keyword: #ff7b72;
  --syn-type: #79c0ff;
  --syn-string: #a5d6ff;
  --syn-comment: #8b949e;
  --syn-number: #79c0ff;
  --syn-annotation: #d2a8ff;
  --syn-method: #d2a8ff;
  --syn-operator: #ff7b72;

  --radius-sm: 6px;
  --radius-md: 10px;
  --radius-lg: 16px;
  --radius-xl: 20px;

  --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.3);
  --shadow-md: 0 4px 12px rgba(0, 0, 0, 0.4);
  --shadow-lg: 0 10px 25px rgba(0, 0, 0, 0.5);
  --shadow-glow: 0 0 20px rgba(59, 130, 246, 0.25);

  --transition-fast: 0.15s ease;
  --transition-normal: 0.25s ease;
}

[data-theme="light"] {
  --bg-primary: #f8fafc;
  --bg-secondary: #ffffff;
  --bg-card: #ffffff;
  --bg-card-hover: #f1f5f9;
  --bg-muted: #f1f5f9;
  --bg-input: #ffffff;

  --border-color: #e2e8f0;
  --border-subtle: #cbd5e1;
  --border-focus: #2563eb;

  --text-primary: #0f172a;
  --text-secondary: #475569;
  --text-muted: #64748b;
  --text-accent: #0284c7;

  --primary: #2563eb;
  --primary-hover: #1d4ed8;
  --primary-gradient: linear-gradient(135deg, #2563eb 0%, #4f46e5 100%);
  --accent-glow: rgba(37, 99, 235, 0.1);

  --badge-bg: #e0f2fe;
  --badge-text: #0369a1;
  --badge-border: #bae6fd;

  --success-bg: #dcfce7;
  --success-text: #15803d;
  --success-border: #bbf7d0;

  --warning-bg: #fef9c3;
  --warning-text: #854d0e;
  --warning-border: #fef08a;

  --code-bg: #0f172a;
  --code-header-bg: #1e293b;
  --code-text: #f8fafc;
  --code-border: #334155;

  --shadow-sm: 0 1px 3px rgba(0, 0, 0, 0.05);
  --shadow-md: 0 4px 12px rgba(0, 0, 0, 0.08);
  --shadow-lg: 0 12px 24px rgba(0, 0, 0, 0.12);
  --shadow-glow: 0 0 20px rgba(37, 99, 235, 0.15);
}

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

html {
  font-size: 16px;
  scroll-behavior: smooth;
  scroll-padding-top: 80px;
}

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

a {
  color: var(--primary);
  text-decoration: none;
  transition: color var(--transition-fast);
}

a:hover {
  text-decoration: underline;
}

button {
  font-family: inherit;
  cursor: pointer;
  border: none;
  background: none;
  outline: none;
}

/* ==========================================================================
   Header & Navigation
   ========================================================================== */
.site-header {
  position: sticky;
  top: 0;
  z-index: 50;
  background-color: rgba(11, 15, 25, 0.88);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border-color);
  transition: background-color var(--transition-normal), border-color var(--transition-normal);
}

[data-theme="light"] .site-header {
  background-color: rgba(255, 255, 255, 0.88);
}

.header-inner {
  max-width: 1440px;
  margin: 0 auto;
  padding: 0.75rem 1.5rem;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
}

.brand-section {
  display: flex;
  align-items: center;
  gap: 0.875rem;
}

.logo-icon {
  width: 40px;
  height: 40px;
  background: var(--primary-gradient);
  border-radius: var(--radius-md);
  display: flex;
  align-items: center;
  justify-content: center;
  color: #ffffff;
  box-shadow: 0 4px 10px rgba(59, 130, 246, 0.3);
  flex-shrink: 0;
}

.brand-titles h1 {
  font-size: 1.15rem;
  font-weight: 700;
  letter-spacing: -0.01em;
  color: var(--text-primary);
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.brand-badge {
  font-size: 0.7rem;
  font-weight: 600;
  background: var(--badge-bg);
  color: var(--badge-text);
  border: 1px solid var(--badge-border);
  padding: 0.15rem 0.5rem;
  border-radius: 9999px;
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

.brand-titles p {
  font-size: 0.8rem;
  color: var(--text-secondary);
}

.header-actions {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  flex-wrap: wrap;
}

/* Quick Search Button in Header */
.search-trigger-btn {
  display: flex;
  align-items: center;
  gap: 0.6rem;
  background-color: var(--bg-card);
  border: 1px solid var(--border-color);
  color: var(--text-secondary);
  padding: 0.5rem 0.875rem;
  border-radius: var(--radius-md);
  font-size: 0.875rem;
  transition: all var(--transition-fast);
}

.search-trigger-btn:hover {
  border-color: var(--primary);
  color: var(--text-primary);
  background-color: var(--bg-card-hover);
}

.search-shortcut-key {
  font-size: 0.725rem;
  padding: 0.15rem 0.4rem;
  background: var(--bg-muted);
  border: 1px solid var(--border-color);
  border-radius: 4px;
  color: var(--text-muted);
}

/* Set Dropdown Select in Header */
.set-select-wrapper {
  position: relative;
  display: flex;
  align-items: center;
}

.set-dropdown-select {
  appearance: none;
  -webkit-appearance: none;
  background-color: var(--bg-card);
  border: 1px solid var(--border-color);
  color: var(--text-primary);
  padding: 0.5rem 2.25rem 0.5rem 0.875rem;
  border-radius: var(--radius-md);
  font-size: 0.875rem;
  font-weight: 500;
  cursor: pointer;
  transition: all var(--transition-fast);
  max-width: 260px;
  text-overflow: ellipsis;
  white-space: nowrap;
  overflow: hidden;
}

.set-dropdown-select:hover {
  border-color: var(--primary);
}

.set-dropdown-select:focus {
  outline: none;
  border-color: var(--primary);
  box-shadow: 0 0 0 3px var(--accent-glow);
}

.select-arrow {
  position: absolute;
  right: 0.75rem;
  pointer-events: none;
  color: var(--text-secondary);
}

/* Action Icon Buttons */
.icon-btn {
  width: 38px;
  height: 38px;
  border-radius: var(--radius-md);
  background-color: var(--bg-card);
  border: 1px solid var(--border-color);
  color: var(--text-secondary);
  display: flex;
  align-items: center;
  justify-content: center;
  transition: all var(--transition-fast);
}

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

/* ==========================================================================
   Set Selector Ribbon (1 to 30)
   ========================================================================== */
.set-ribbon-bar {
  background-color: var(--bg-secondary);
  border-bottom: 1px solid var(--border-color);
  padding: 0.65rem 1.5rem;
}

.ribbon-container {
  max-width: 1440px;
  margin: 0 auto;
  display: flex;
  align-items: center;
  gap: 0.75rem;
}

.ribbon-label {
  font-size: 0.8rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: var(--text-muted);
  white-space: nowrap;
  display: flex;
  align-items: center;
  gap: 0.35rem;
}

.ribbon-scroll-wrapper {
  position: relative;
  flex: 1;
  display: flex;
  align-items: center;
  overflow: hidden;
}

.ribbon-nav-btn {
  width: 28px;
  height: 28px;
  border-radius: var(--radius-sm);
  background-color: var(--bg-card);
  border: 1px solid var(--border-color);
  color: var(--text-secondary);
  display: flex;
  align-items: center;
  justify-content: center;
  flex-shrink: 0;
  z-index: 2;
  transition: all var(--transition-fast);
}

.ribbon-nav-btn:hover {
  color: var(--text-primary);
  border-color: var(--primary);
}

.ribbon-scroll {
  display: flex;
  align-items: center;
  gap: 0.4rem;
  overflow-x: auto;
  scroll-behavior: smooth;
  scrollbar-width: thin;
  scrollbar-color: var(--border-color) transparent;
  padding: 0.25rem 0.5rem;
}

.ribbon-scroll::-webkit-scrollbar {
  height: 4px;
}

.ribbon-scroll::-webkit-scrollbar-thumb {
  background: var(--border-color);
  border-radius: 4px;
}

.set-pill-btn {
  padding: 0.35rem 0.75rem;
  border-radius: 9999px;
  background-color: var(--bg-card);
  border: 1px solid var(--border-color);
  color: var(--text-secondary);
  font-size: 0.825rem;
  font-weight: 600;
  white-space: nowrap;
  display: flex;
  align-items: center;
  gap: 0.4rem;
  transition: all var(--transition-fast);
  cursor: pointer;
}

.set-pill-btn:hover {
  border-color: var(--primary);
  color: var(--text-primary);
  transform: translateY(-1px);
}

.set-pill-btn.active {
  background: var(--primary-gradient);
  border-color: transparent;
  color: #ffffff;
  box-shadow: 0 2px 8px rgba(59, 130, 246, 0.4);
}

.set-pill-num {
  font-family: var(--font-mono);
  font-size: 0.775rem;
}

.all-sets-grid-toggle {
  display: flex;
  align-items: center;
  gap: 0.35rem;
  padding: 0.35rem 0.75rem;
  border-radius: var(--radius-sm);
  background-color: var(--bg-card);
  border: 1px solid var(--border-color);
  color: var(--text-secondary);
  font-size: 0.8rem;
  font-weight: 500;
  white-space: nowrap;
  cursor: pointer;
  transition: all var(--transition-fast);
}

.all-sets-grid-toggle:hover {
  color: var(--text-primary);
  border-color: var(--primary);
}

/* ==========================================================================
   Main Content Layout
   ========================================================================== */
.main-wrapper {
  max-width: 1440px;
  width: 100%;
  margin: 0 auto;
  padding: 1.75rem 1.5rem 4rem;
  flex: 1;
}

/* Set Hero Banner */
.set-hero-card {
  background: linear-gradient(180deg, var(--bg-card) 0%, rgba(22, 31, 48, 0.6) 100%);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  padding: 2rem;
  margin-bottom: 1.75rem;
  box-shadow: var(--shadow-md);
  position: relative;
  overflow: hidden;
}

[data-theme="light"] .set-hero-card {
  background: linear-gradient(180deg, #ffffff 0%, #f8fafc 100%);
}

.set-hero-card::before {
  content: "";
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 4px;
  background: var(--primary-gradient);
}

.set-hero-header {
  display: flex;
  justify-content: space-between;
  align-items: flex-start;
  gap: 1.5rem;
  margin-bottom: 1.25rem;
  flex-wrap: wrap;
}

.set-meta-tag {
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
  font-family: var(--font-mono);
  font-size: 0.8rem;
  font-weight: 700;
  padding: 0.3rem 0.75rem;
  border-radius: 9999px;
  background: var(--badge-bg);
  color: var(--badge-text);
  border: 1px solid var(--badge-border);
  margin-bottom: 0.5rem;
}

.set-title {
  font-size: 1.85rem;
  font-weight: 800;
  color: var(--text-primary);
  letter-spacing: -0.02em;
  line-height: 1.25;
}

.hero-actions-group {
  display: flex;
  align-items: center;
  gap: 0.6rem;
  flex-wrap: wrap;
}

.btn-primary {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  background: var(--primary-gradient);
  color: #ffffff;
  padding: 0.6rem 1.15rem;
  border-radius: var(--radius-md);
  font-size: 0.875rem;
  font-weight: 600;
  box-shadow: 0 4px 12px rgba(59, 130, 246, 0.3);
  transition: all var(--transition-fast);
}

.btn-primary:hover {
  box-shadow: 0 6px 16px rgba(59, 130, 246, 0.45);
  transform: translateY(-1px);
  text-decoration: none;
  color: #ffffff;
}

.btn-secondary {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  background-color: var(--bg-muted);
  border: 1px solid var(--border-color);
  color: var(--text-primary);
  padding: 0.6rem 1.15rem;
  border-radius: var(--radius-md);
  font-size: 0.875rem;
  font-weight: 600;
  transition: all var(--transition-fast);
}

.btn-secondary:hover {
  background-color: var(--bg-card-hover);
  border-color: var(--primary);
  text-decoration: none;
}

/* Problem Statement Box */
.problem-box {
  background-color: var(--bg-muted);
  border: 1px solid var(--border-color);
  border-left: 4px solid var(--primary);
  border-radius: var(--radius-md);
  padding: 1.25rem;
  display: flex;
  align-items: flex-start;
  gap: 1rem;
}

.problem-icon {
  color: var(--primary);
  flex-shrink: 0;
  margin-top: 2px;
}

.problem-content h3 {
  font-size: 0.85rem;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  font-weight: 700;
  color: var(--text-accent);
  margin-bottom: 0.35rem;
}

.problem-content p {
  color: var(--text-primary);
  font-size: 0.95rem;
  line-height: 1.6;
}

/* ==========================================================================
   Navigation Tabs
   ========================================================================== */
.tabs-nav-bar {
  display: flex;
  gap: 0.5rem;
  border-bottom: 1px solid var(--border-color);
  margin-bottom: 2rem;
  overflow-x: auto;
  scrollbar-width: none;
}

.tabs-nav-bar::-webkit-scrollbar {
  display: none;
}

.tab-btn {
  padding: 0.75rem 1.25rem;
  font-size: 0.925rem;
  font-weight: 600;
  color: var(--text-secondary);
  border-bottom: 2px solid transparent;
  display: flex;
  align-items: center;
  gap: 0.5rem;
  white-space: nowrap;
  transition: all var(--transition-fast);
  cursor: pointer;
}

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

.tab-btn.active {
  color: var(--primary);
  border-bottom-color: var(--primary);
}

.tab-count-badge {
  font-size: 0.75rem;
  padding: 0.1rem 0.45rem;
  border-radius: 9999px;
  background-color: var(--bg-muted);
  color: var(--text-secondary);
  font-weight: 700;
}

.tab-btn.active .tab-count-badge {
  background-color: var(--badge-bg);
  color: var(--badge-text);
}

/* ==========================================================================
   Sections & Cards
   ========================================================================== */
.tab-pane {
  display: none;
  animation: fadeIn 0.2s ease-in-out;
}

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

.tab-pane.active + .tab-pane.active {
  margin-top: 3rem;
  padding-top: 2rem;
  border-top: 1px dashed var(--border-color);
}

@keyframes fadeIn {
  from { opacity: 0; transform: translateY(4px); }
  to { opacity: 1; transform: translateY(0); }
}

.section-title-bar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 1.25rem;
  flex-wrap: wrap;
  gap: 0.75rem;
}

.section-title-bar h2 {
  font-size: 1.35rem;
  font-weight: 700;
  color: var(--text-primary);
  display: flex;
  align-items: center;
  gap: 0.6rem;
}

.section-desc {
  font-size: 0.875rem;
  color: var(--text-secondary);
}

/* Part A Short Answers */
.part-a-filter-bar {
  margin-bottom: 1.25rem;
  display: flex;
  align-items: center;
  gap: 0.75rem;
}

.part-a-search-input {
  flex: 1;
  max-width: 450px;
  background-color: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  padding: 0.6rem 1rem;
  color: var(--text-primary);
  font-size: 0.875rem;
  transition: border-color var(--transition-fast);
}

.part-a-search-input:focus {
  outline: none;
  border-color: var(--primary);
  box-shadow: 0 0 0 3px var(--accent-glow);
}

.part-a-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(480px, 1fr));
  gap: 1.25rem;
}

@media (max-width: 768px) {
  .part-a-grid {
    grid-template-columns: 1fr;
  }
}

.qa-card {
  background-color: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  padding: 1.25rem;
  transition: border-color var(--transition-fast), transform var(--transition-fast);
  display: flex;
  flex-direction: column;
}

.qa-card:hover {
  border-color: var(--border-focus);
}

.qa-header {
  display: flex;
  align-items: flex-start;
  gap: 0.75rem;
  margin-bottom: 0.875rem;
}

.q-badge {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  font-weight: 700;
  background: var(--primary-gradient);
  color: #ffffff;
  padding: 0.2rem 0.55rem;
  border-radius: 6px;
  flex-shrink: 0;
  margin-top: 2px;
}

.qa-question {
  font-size: 0.95rem;
  font-weight: 600;
  color: var(--text-primary);
  line-height: 1.45;
}

.qa-answer {
  background-color: var(--bg-muted);
  border-radius: var(--radius-sm);
  padding: 0.875rem 1rem;
  font-size: 0.9rem;
  color: var(--text-secondary);
  border-left: 3px solid #6366f1;
  line-height: 1.55;
  margin-top: auto;
}

.qa-answer strong {
  color: var(--text-primary);
}

/* Part B: Question Requirements */
.requirements-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(320px, 1fr));
  gap: 1rem;
  margin-bottom: 2rem;
}

.req-card {
  background-color: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  padding: 1.25rem;
}

.req-header {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  font-size: 0.825rem;
  font-weight: 700;
  color: var(--text-accent);
  text-transform: uppercase;
  letter-spacing: 0.05em;
  margin-bottom: 0.5rem;
}

.req-text {
  font-size: 0.9rem;
  color: var(--text-secondary);
  line-height: 1.5;
}

/* Aim & Algorithm Cards */
.aim-card {
  background-color: var(--bg-card);
  border: 1px solid var(--border-color);
  border-left: 4px solid #10b981;
  border-radius: var(--radius-md);
  padding: 1.25rem;
  margin-bottom: 1.75rem;
}

.aim-title {
  font-size: 0.85rem;
  font-weight: 700;
  text-transform: uppercase;
  color: #10b981;
  margin-bottom: 0.35rem;
  display: flex;
  align-items: center;
  gap: 0.4rem;
}

.aim-text {
  font-size: 0.95rem;
  color: var(--text-primary);
}

.algo-card {
  background-color: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  padding: 1.5rem;
  margin-bottom: 2rem;
}

.algo-title {
  font-size: 1.1rem;
  font-weight: 700;
  color: var(--text-primary);
  margin-bottom: 1rem;
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.algo-timeline {
  display: flex;
  flex-direction: column;
  gap: 0.875rem;
}

.algo-step-item {
  display: flex;
  align-items: flex-start;
  gap: 0.875rem;
}

.algo-step-num {
  width: 28px;
  height: 28px;
  border-radius: 50%;
  background-color: var(--badge-bg);
  color: var(--badge-text);
  border: 1px solid var(--badge-border);
  font-size: 0.8rem;
  font-weight: 700;
  font-family: var(--font-mono);
  display: flex;
  align-items: center;
  justify-content: center;
  flex-shrink: 0;
  margin-top: 1px;
}

.algo-step-text {
  font-size: 0.925rem;
  color: var(--text-secondary);
  line-height: 1.5;
}

/* ==========================================================================
   Code Containers & Blocks
   ========================================================================== */
.code-container {
  background-color: var(--code-bg);
  border: 1px solid var(--code-border);
  border-radius: var(--radius-lg);
  overflow: hidden;
  margin-bottom: 2rem;
  box-shadow: var(--shadow-md);
}

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

.code-file-info {
  display: flex;
  align-items: center;
  gap: 0.75rem;
}

.code-file-name {
  font-family: var(--font-mono);
  font-size: 0.85rem;
  font-weight: 600;
  color: var(--text-primary);
  display: flex;
  align-items: center;
  gap: 0.4rem;
}

.code-badge {
  font-size: 0.7rem;
  font-family: var(--font-mono);
  font-weight: 700;
  background-color: rgba(59, 130, 246, 0.2);
  color: #60a5fa;
  border: 1px solid rgba(59, 130, 246, 0.3);
  padding: 0.1rem 0.45rem;
  border-radius: 4px;
  text-transform: uppercase;
}

.code-lines-count {
  font-size: 0.775rem;
  color: var(--text-muted);
}

.code-header-actions {
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.code-action-btn {
  display: inline-flex;
  align-items: center;
  gap: 0.35rem;
  background-color: rgba(255, 255, 255, 0.06);
  border: 1px solid rgba(255, 255, 255, 0.1);
  color: var(--text-secondary);
  font-size: 0.775rem;
  font-weight: 500;
  padding: 0.35rem 0.65rem;
  border-radius: var(--radius-sm);
  transition: all var(--transition-fast);
}

.code-action-btn:hover {
  background-color: rgba(255, 255, 255, 0.12);
  color: #ffffff;
}

.code-action-btn.copied {
  background-color: rgba(34, 197, 94, 0.25);
  color: #4ade80;
  border-color: rgba(34, 197, 94, 0.4);
}

.code-note-box {
  background-color: rgba(59, 130, 246, 0.08);
  border-bottom: 1px solid var(--code-border);
  padding: 0.75rem 1.25rem;
  font-size: 0.85rem;
  color: var(--text-secondary);
  display: flex;
  align-items: flex-start;
  gap: 0.6rem;
}

.code-note-icon {
  color: var(--primary);
  flex-shrink: 0;
  margin-top: 2px;
}

.code-body {
  position: relative;
  overflow-x: auto;
  padding: 1.25rem 1.25rem 1.25rem 0.5rem;
  font-family: var(--font-mono);
  font-size: 0.875rem;
  line-height: 1.6;
  color: var(--code-text);
  max-height: 600px;
  scrollbar-width: thin;
  scrollbar-color: var(--border-color) transparent;
}

.code-body pre {
  margin: 0;
  white-space: pre;
}

.code-body.wrap-code pre {
  white-space: pre-wrap;
  word-break: break-word;
}

/* Line numbers table layout */
.code-table {
  border-collapse: collapse;
  width: 100%;
}

.code-table td {
  padding: 0 0.5rem;
  vertical-align: top;
}

.line-num {
  color: var(--text-muted);
  user-select: none;
  text-align: right;
  width: 45px;
  font-size: 0.8rem;
  opacity: 0.6;
}

.line-code {
  color: var(--code-text);
  white-space: pre;
}

.wrap-code .line-code {
  white-space: pre-wrap;
  word-break: break-word;
}

/* Syntax Highlight classes */
.syn-kw { color: var(--syn-keyword); font-weight: 600; }
.syn-typ { color: var(--syn-type); }
.syn-str { color: var(--syn-string); }
.syn-cmt { color: var(--syn-comment); font-style: italic; }
.syn-num { color: var(--syn-number); }
.syn-ann { color: var(--syn-annotation); font-weight: 600; }

/* Sample Input & Output Terminal Box */
.terminal-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(360px, 1fr));
  gap: 1.25rem;
  margin-bottom: 2rem;
}

.terminal-card {
  background-color: #0d1117;
  border: 1px solid #30363d;
  border-radius: var(--radius-md);
  overflow: hidden;
}

.terminal-header {
  background-color: #161b22;
  padding: 0.5rem 0.875rem;
  display: flex;
  align-items: center;
  justify-content: space-between;
  border-bottom: 1px solid #30363d;
}

.terminal-dots {
  display: flex;
  align-items: center;
  gap: 6px;
}

.dot {
  width: 10px;
  height: 10px;
  border-radius: 50%;
}

.dot-red { background-color: #ff5f56; }
.dot-yellow { background-color: #ffbd2e; }
.dot-green { background-color: #27c93f; }

.terminal-title {
  font-family: var(--font-mono);
  font-size: 0.775rem;
  color: #8b949e;
  font-weight: 600;
}

.terminal-body {
  padding: 1rem;
  font-family: var(--font-mono);
  font-size: 0.85rem;
  line-height: 1.5;
  color: #58a6ff;
  overflow-x: auto;
  white-space: pre-wrap;
}

.terminal-body.output {
  color: #7ee787;
}

/* Debugging Note & Result Cards */
.debug-card {
  background-color: var(--bg-card);
  border: 1px solid var(--border-color);
  border-left: 4px solid #f59e0b;
  border-radius: var(--radius-md);
  padding: 1.25rem;
  margin-bottom: 1.5rem;
  display: flex;
  align-items: flex-start;
  gap: 1rem;
}

.debug-icon {
  color: #f59e0b;
  flex-shrink: 0;
  margin-top: 2px;
}

.debug-title {
  font-size: 0.85rem;
  font-weight: 700;
  text-transform: uppercase;
  color: #f59e0b;
  margin-bottom: 0.35rem;
}

.debug-text {
  font-size: 0.925rem;
  color: var(--text-secondary);
}

.result-card {
  background: linear-gradient(135deg, rgba(34, 197, 94, 0.08) 0%, rgba(16, 185, 129, 0.05) 100%);
  border: 1px solid var(--success-border);
  border-radius: var(--radius-md);
  padding: 1.25rem;
  margin-bottom: 2rem;
  display: flex;
  align-items: flex-start;
  gap: 1rem;
}

.result-icon {
  color: #22c55e;
  flex-shrink: 0;
  margin-top: 2px;
}

.result-title {
  font-size: 0.85rem;
  font-weight: 700;
  text-transform: uppercase;
  color: #22c55e;
  margin-bottom: 0.35rem;
}

.result-text {
  font-size: 0.95rem;
  color: var(--text-primary);
}

/* ==========================================================================
   Bottom Navigation Bar
   ========================================================================== */
.bottom-nav-bar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 1.5rem 0 0;
  border-top: 1px solid var(--border-color);
  margin-top: 2rem;
  gap: 1rem;
  flex-wrap: wrap;
}

.nav-set-btn {
  display: inline-flex;
  align-items: center;
  gap: 0.6rem;
  background-color: var(--bg-card);
  border: 1px solid var(--border-color);
  padding: 0.75rem 1.25rem;
  border-radius: var(--radius-md);
  color: var(--text-primary);
  font-size: 0.875rem;
  font-weight: 600;
  transition: all var(--transition-fast);
}

.nav-set-btn:hover:not(:disabled) {
  border-color: var(--primary);
  background-color: var(--bg-card-hover);
  transform: translateY(-1px);
}

.nav-set-btn:disabled {
  opacity: 0.4;
  cursor: not-allowed;
}

.nav-subtext {
  font-size: 0.75rem;
  color: var(--text-muted);
  display: block;
}

.current-indicator {
  font-family: var(--font-mono);
  font-size: 0.875rem;
  color: var(--text-secondary);
  font-weight: 600;
}

/* ==========================================================================
   Modals: Search Modal & All Sets Grid Modal & PDF Preview Modal
   ========================================================================== */
.modal-overlay {
  position: fixed;
  inset: 0;
  background-color: rgba(0, 0, 0, 0.75);
  backdrop-filter: blur(6px);
  z-index: 100;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 1.5rem;
  opacity: 0;
  pointer-events: none;
  transition: opacity var(--transition-fast);
}

.modal-overlay.open {
  opacity: 1;
  pointer-events: auto;
}

.modal-container {
  background-color: var(--bg-secondary);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  width: 100%;
  max-width: 760px;
  max-height: 85vh;
  display: flex;
  flex-direction: column;
  box-shadow: var(--shadow-lg);
  overflow: hidden;
  transform: scale(0.96);
  transition: transform var(--transition-fast);
}

.modal-overlay.open .modal-container {
  transform: scale(1);
}

.modal-container.large {
  max-width: 1050px;
  height: 85vh;
}

.modal-header {
  padding: 1rem 1.25rem;
  border-bottom: 1px solid var(--border-color);
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
}

.modal-header h3 {
  font-size: 1.1rem;
  font-weight: 700;
  color: var(--text-primary);
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.modal-close-btn {
  width: 32px;
  height: 32px;
  border-radius: var(--radius-sm);
  color: var(--text-secondary);
  display: flex;
  align-items: center;
  justify-content: center;
  transition: all var(--transition-fast);
}

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

/* Search Modal Specifics */
.modal-search-box {
  padding: 1rem 1.25rem;
  border-bottom: 1px solid var(--border-color);
  display: flex;
  align-items: center;
  gap: 0.75rem;
  background-color: var(--bg-card);
}

.modal-search-input {
  flex: 1;
  background: transparent;
  border: none;
  color: var(--text-primary);
  font-size: 1.05rem;
  outline: none;
}

.modal-search-results {
  flex: 1;
  overflow-y: auto;
  padding: 0.75rem;
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
}

.search-result-item {
  padding: 0.875rem 1rem;
  border-radius: var(--radius-md);
  background-color: var(--bg-card);
  border: 1px solid var(--border-color);
  cursor: pointer;
  transition: all var(--transition-fast);
  display: flex;
  flex-direction: column;
  gap: 0.35rem;
}

.search-result-item:hover {
  border-color: var(--primary);
  background-color: var(--bg-card-hover);
  transform: translateX(2px);
}

.search-result-header {
  display: flex;
  align-items: center;
  gap: 0.6rem;
}

.search-result-title {
  font-weight: 700;
  font-size: 0.95rem;
  color: var(--text-primary);
}

.search-result-match {
  font-size: 0.85rem;
  color: var(--text-secondary);
  line-height: 1.4;
}

.search-result-match mark {
  background-color: rgba(234, 179, 8, 0.3);
  color: #fef08a;
  border-radius: 2px;
  padding: 0 2px;
}

/* All Sets Grid Modal Specifics */
.all-sets-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
  gap: 0.875rem;
  padding: 1.25rem;
  overflow-y: auto;
}

.grid-set-card {
  padding: 1rem;
  border-radius: var(--radius-md);
  background-color: var(--bg-card);
  border: 1px solid var(--border-color);
  cursor: pointer;
  transition: all var(--transition-fast);
  display: flex;
  flex-direction: column;
  gap: 0.4rem;
}

.grid-set-card:hover {
  border-color: var(--primary);
  background-color: var(--bg-card-hover);
  transform: translateY(-2px);
}

.grid-set-card.active {
  border-color: var(--primary);
  background: var(--accent-glow);
}

.grid-set-top {
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.grid-set-badge {
  font-family: var(--font-mono);
  font-size: 0.725rem;
  font-weight: 700;
  padding: 0.15rem 0.45rem;
  border-radius: 4px;
  background-color: var(--badge-bg);
  color: var(--badge-text);
}

.grid-set-name {
  font-size: 0.95rem;
  font-weight: 700;
  color: var(--text-primary);
}

.grid-set-preview {
  font-size: 0.8rem;
  color: var(--text-muted);
  display: -webkit-box;
  -webkit-line-clamp: 2;
  -webkit-box-orient: vertical;
  overflow: hidden;
}

/* PDF Preview Frame */
.pdf-frame-wrapper {
  flex: 1;
  position: relative;
  background-color: #1e293b;
}

.pdf-iframe {
  width: 100%;
  height: 100%;
  border: none;
}

.pdf-modal-footer {
  padding: 0.75rem 1.25rem;
  border-top: 1px solid var(--border-color);
  display: flex;
  align-items: center;
  justify-content: space-between;
  background-color: var(--bg-card);
}

/* Toast Notifications */
.toast-container {
  position: fixed;
  bottom: 1.5rem;
  right: 1.5rem;
  z-index: 200;
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
}

.toast {
  background-color: var(--bg-card);
  border: 1px solid var(--border-color);
  border-left: 4px solid var(--primary);
  color: var(--text-primary);
  padding: 0.75rem 1.25rem;
  border-radius: var(--radius-md);
  font-size: 0.875rem;
  font-weight: 500;
  box-shadow: var(--shadow-lg);
  display: flex;
  align-items: center;
  gap: 0.6rem;
  animation: slideIn 0.25s ease-out;
}

@keyframes slideIn {
  from { transform: translateX(100%); opacity: 0; }
  to { transform: translateX(0); opacity: 1; }
}

/* ==========================================================================
   Footer
   ========================================================================== */
.site-footer {
  background-color: var(--bg-secondary);
  border-top: 1px solid var(--border-color);
  padding: 1.75rem 1.5rem;
  margin-top: auto;
}

.footer-inner {
  max-width: 1440px;
  margin: 0 auto;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  flex-wrap: wrap;
  font-size: 0.85rem;
  color: var(--text-muted);
}

/* ==========================================================================
   Print Styles
   ========================================================================== */
@media print {
  body {
    background: #ffffff !important;
    color: #000000 !important;
  }

  .site-header,
  .set-ribbon-bar,
  .tabs-nav-bar,
  .hero-actions-group,
  .part-a-filter-bar,
  .code-header-actions,
  .bottom-nav-bar,
  .site-footer,
  .modal-overlay,
  .toast-container {
    display: none !important;
  }

  .tab-pane {
    display: block !important;
    margin-bottom: 2rem;
    page-break-inside: avoid;
  }

  .set-hero-card,
  .qa-card,
  .req-card,
  .algo-card,
  .code-container,
  .terminal-card,
  .debug-card,
  .result-card {
    background: #ffffff !important;
    border: 1px solid #cccccc !important;
    color: #000000 !important;
    box-shadow: none !important;
  }

  .code-body {
    max-height: none !important;
    overflow: visible !important;
    color: #000000 !important;
    background: #f8fafc !important;
  }

  .line-code, .syn-kw, .syn-typ, .syn-str, .syn-cmt, .syn-num {
    color: #000000 !important;
  }
}