/* ==========================================
   UITS_Dev_Lab Single Page Application Styles
   Minimal, High-Contrast, Modular CSS3
   No Gradients | No Emojis | No Em-dashes
   ========================================== */

/* Design System & Root Theme Variables */
:root {
  /* Common System Properties */
  --font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Oxygen, Ubuntu, Cantarell, "Open Sans", "Helvetica Neue", sans-serif;
  --font-mono: "SFMono-Regular", Consolas, "Liberation Mono", Menlo, Courier, monospace;
  --transition-fast: 0.15s ease;
  --transition-normal: 0.25s ease;
  --radius-sm: 4px;
  --radius-md: 6px;
  --radius-lg: 8px;
  --max-width: 1200px;
  --header-height: 64px;

  /* Default Light Theme Tokens */
  --bg-body: #f8f9fa;
  --bg-surface: #ffffff;
  --bg-subtle: #f1f5f9;
  --bg-hover: #e2e8f0;
  --text-main: #0f172a;
  --text-muted: #475569;
  --text-inverse: #ffffff;
  --border-color: #cbd5e1;
  --border-strong: #94a3b8;
  --accent-blue: #0284c7;
  --accent-blue-hover: #0369a1;
  --accent-green: #059669;
  --accent-green-hover: #047857;
  --badge-cli-bg: #e0f2fe;
  --badge-cli-text: #0369a1;
  --badge-git-bg: #dcfce7;
  --badge-git-text: #15803d;
  --badge-scaffold-bg: #fef3c7;
  --badge-scaffold-text: #b45309;
  --badge-tools-bg: #f3e8ff;
  --badge-tools-text: #6b21a8;
  --modal-backdrop: rgba(15, 23, 42, 0.6);
  --shadow-card: 0 1px 3px rgba(0, 0, 0, 0.08), 0 1px 2px rgba(0, 0, 0, 0.04);
}

/* Strict Dark Mode Theme Tokens */
[data-theme="dark"] {
  --bg-body: #000000;
  --bg-surface: #0a0a0a;
  --bg-subtle: #141414;
  --bg-hover: #222222;
  --text-main: #ffffff;
  --text-muted: #a1a1aa;
  --text-inverse: #000000;
  --border-color: #27272a;
  --border-strong: #52525b;
  --accent-blue: #38bdf8;
  --accent-blue-hover: #7dd3fc;
  --accent-green: #34d399;
  --accent-green-hover: #6ee7b7;
  --badge-cli-bg: #0c4a6e;
  --badge-cli-text: #e0f2fe;
  --badge-git-bg: #064e3b;
  --badge-git-text: #dcfce7;
  --badge-scaffold-bg: #78350f;
  --badge-scaffold-text: #fef3c7;
  --badge-tools-bg: #581c87;
  --badge-tools-text: #f3e8ff;
  --modal-backdrop: rgba(0, 0, 0, 0.85);
  --shadow-card: 0 1px 3px rgba(255, 255, 255, 0.05);
}

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

html {
  scroll-behavior: smooth;
}

body {
  font-family: var(--font-family);
  background-color: var(--bg-body);
  color: var(--text-main);
  line-height: 1.6;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  transition: background-color var(--transition-normal), color var(--transition-normal);
}

/* Accessibility Focus Ring */
:focus-visible {
  outline: 2px solid var(--accent-blue);
  outline-offset: 2px;
}

/* Layout Containers */
.container {
  width: 100%;
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 1.5rem;
}

main {
  flex: 1;
  padding-top: 2rem;
  padding-bottom: 4rem;
  width: 100%;
}

/* Section Switching (SPA Router) */
.page-section {
  display: none;
  scroll-margin-top: calc(var(--header-height) + 1.5rem);
  animation: fadeIn var(--transition-fast) ease-in-out;
}

.page-section.active {
  display: block;
}

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

/* ==========================================
   Header & Navigation
   ========================================== */
.site-header {
  position: sticky;
  top: 0;
  left: 0;
  width: 100%;
  min-height: var(--header-height);
  background-color: var(--bg-surface);
  border-bottom: 1px solid var(--border-color);
  z-index: 100;
  transition: background-color var(--transition-normal), border-color var(--transition-normal);
}

.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  min-height: var(--header-height);
  padding-top: 0.5rem;
  padding-bottom: 0.5rem;
}

.brand-logo {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  text-decoration: none;
  color: var(--text-main);
  font-weight: 700;
  font-size: 1.15rem;
  letter-spacing: -0.02em;
}

.brand-badge {
  background-color: var(--accent-blue);
  color: var(--text-inverse);
  padding: 0.15rem 0.5rem;
  border-radius: var(--radius-sm);
  font-size: 0.75rem;
  font-family: var(--font-mono);
  font-weight: 600;
}

.nav-desktop {
  display: flex;
  align-items: center;
  gap: 1.5rem;
}

.nav-links {
  display: flex;
  align-items: center;
  gap: 0.25rem;
  list-style: none;
}

.nav-link {
  text-decoration: none;
  color: var(--text-muted);
  font-size: 0.95rem;
  font-weight: 500;
  padding: 0.4rem 0.75rem;
  border-radius: var(--radius-sm);
  transition: color var(--transition-fast), background-color var(--transition-fast);
}

.nav-link:hover, .nav-link.active {
  color: var(--text-main);
  background-color: var(--bg-subtle);
}

.nav-link.active {
  border-bottom: 2px solid var(--accent-blue);
  border-radius: var(--radius-sm) var(--radius-sm) 0 0;
}

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

/* Theme Toggle Switch */
.theme-toggle-btn {
  background-color: var(--bg-subtle);
  border: 1px solid var(--border-color);
  color: var(--text-main);
  padding: 0.4rem 0.8rem;
  border-radius: var(--radius-sm);
  cursor: pointer;
  font-size: 0.85rem;
  font-weight: 600;
  display: flex;
  align-items: center;
  gap: 0.4rem;
  transition: background-color var(--transition-fast), border-color var(--transition-fast);
}

.theme-toggle-btn:hover {
  background-color: var(--bg-hover);
  border-color: var(--border-strong);
}

/* Mobile Hamburger Trigger */
.mobile-hamburger {
  display: none;
  background: transparent;
  border: 1px solid var(--border-color);
  color: var(--text-main);
  width: 40px;
  height: 40px;
  border-radius: var(--radius-sm);
  cursor: pointer;
  align-items: center;
  justify-content: center;
  flex-direction: column;
  gap: 5px;
}

.hamburger-line {
  width: 20px;
  height: 2px;
  background-color: var(--text-main);
  transition: transform var(--transition-fast), opacity var(--transition-fast);
}

/* Mobile Slide-out Sidebar Menu */
.mobile-sidebar-overlay {
  display: none;
  position: fixed;
  top: 0;
  left: 0;
  width: 100vw;
  height: 100vh;
  background-color: var(--modal-backdrop);
  z-index: 200;
}

.mobile-sidebar-overlay.active {
  display: block;
}

.mobile-sidebar {
  position: fixed;
  top: 0;
  right: -280px;
  width: 280px;
  height: 100%;
  background-color: var(--bg-surface);
  border-left: 1px solid var(--border-color);
  padding: 1.5rem;
  display: flex;
  flex-direction: column;
  gap: 1.5rem;
  z-index: 210;
  transition: right var(--transition-normal);
}

.mobile-sidebar.active {
  right: 0;
}

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

.mobile-close-btn {
  background: transparent;
  border: 1px solid var(--border-color);
  color: var(--text-main);
  width: 32px;
  height: 32px;
  border-radius: var(--radius-sm);
  cursor: pointer;
  font-weight: bold;
}

.mobile-nav-links {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
}

.mobile-nav-link {
  display: block;
  padding: 0.75rem 1rem;
  color: var(--text-main);
  text-decoration: none;
  font-weight: 500;
  border-radius: var(--radius-sm);
  border: 1px solid transparent;
}

.mobile-nav-link:hover, .mobile-nav-link.active {
  background-color: var(--bg-subtle);
  border-color: var(--border-color);
}

/* Responsive Nav Layout */
@media (max-width: 768px) {
  .nav-desktop {
    display: none;
  }
  .mobile-hamburger {
    display: flex;
  }
}

/* ==========================================
   Home Section & Interactive Roadmap
   ========================================== */
.hero-wrapper {
  text-align: center;
  padding: 3rem 1rem;
  max-width: 800px;
  margin: 0 auto 3rem auto;
  border-bottom: 1px solid var(--border-color);
}

.hero-tag {
  display: inline-block;
  background-color: var(--bg-subtle);
  border: 1px solid var(--border-color);
  color: var(--accent-blue);
  font-size: 0.85rem;
  font-weight: 600;
  padding: 0.25rem 0.75rem;
  border-radius: 999px;
  margin-bottom: 1rem;
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

.hero-title {
  font-size: 2.25rem;
  font-weight: 800;
  letter-spacing: -0.03em;
  margin-bottom: 1rem;
  line-height: 1.25;
}

.hero-motto {
  font-size: 1.15rem;
  color: var(--text-muted);
  font-weight: 400;
}

.section-heading-block {
  margin-bottom: 2rem;
}

.section-title {
  font-size: 1.5rem;
  font-weight: 700;
  letter-spacing: -0.02em;
  margin-bottom: 0.25rem;
}

.section-subtitle {
  color: var(--text-muted);
  font-size: 0.95rem;
}

/* Roadmap Grid Layout */
.roadmap-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 1rem;
  margin-bottom: 3rem;
}

@media (max-width: 992px) {
  .roadmap-grid {
    grid-template-columns: repeat(2, 1fr);
  }
}

@media (max-width: 576px) {
  .roadmap-grid {
    grid-template-columns: 1fr;
  }
}

.roadmap-card {
  background-color: var(--bg-surface);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  padding: 1.5rem;
  cursor: pointer;
  position: relative;
  transition: transform var(--transition-fast), border-color var(--transition-fast), box-shadow var(--transition-fast);
}

.roadmap-card:hover {
  transform: translateY(-3px);
  border-color: var(--accent-blue);
  box-shadow: var(--shadow-card);
}

.roadmap-step-badge {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 28px;
  height: 28px;
  background-color: var(--accent-blue);
  color: var(--text-inverse);
  font-weight: 700;
  font-size: 0.85rem;
  border-radius: var(--radius-sm);
  margin-bottom: 1rem;
}

.roadmap-card-title {
  font-size: 1.05rem;
  font-weight: 700;
  margin-bottom: 0.5rem;
}

.roadmap-card-desc {
  font-size: 0.875rem;
  color: var(--text-muted);
  line-height: 1.45;
  margin-bottom: 1rem;
}

.roadmap-action-link {
  font-size: 0.85rem;
  font-weight: 600;
  color: var(--accent-blue);
  display: flex;
  align-items: center;
  gap: 0.25rem;
}

/* ==========================================
   Setup Guides Section
   ========================================== */
.controls-bar {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  margin-bottom: 2rem;
  background-color: var(--bg-surface);
  border: 1px solid var(--border-color);
  padding: 1rem;
  border-radius: var(--radius-md);
}

.filter-group {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
}

.filter-btn {
  background-color: var(--bg-subtle);
  border: 1px solid var(--border-color);
  color: var(--text-muted);
  padding: 0.4rem 0.85rem;
  border-radius: var(--radius-sm);
  font-size: 0.85rem;
  font-weight: 600;
  cursor: pointer;
  transition: all var(--transition-fast);
}

.filter-btn:hover, .filter-btn.active {
  color: var(--text-main);
  background-color: var(--bg-hover);
  border-color: var(--border-strong);
}

.filter-btn.active {
  background-color: var(--accent-blue);
  color: var(--text-inverse);
  border-color: var(--accent-blue);
}

.search-box {
  position: relative;
  min-width: 240px;
  flex: 1;
  max-width: 320px;
}

.search-input {
  width: 100%;
  padding: 0.45rem 0.75rem;
  background-color: var(--bg-body);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-sm);
  color: var(--text-main);
  font-size: 0.875rem;
  font-family: inherit;
}

.search-input:focus {
  border-color: var(--accent-blue);
  background-color: var(--bg-surface);
}

.guides-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(320px, 1fr));
  gap: 1.5rem;
}

.guide-card {
  background-color: var(--bg-surface);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  padding: 1.5rem;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  transition: border-color var(--transition-fast), box-shadow var(--transition-fast);
}

.guide-card:hover {
  border-color: var(--border-strong);
  box-shadow: var(--shadow-card);
}

.guide-header {
  margin-bottom: 1rem;
}

.card-meta-row {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 0.75rem;
}

.category-tag {
  font-size: 0.75rem;
  font-weight: 700;
  padding: 0.15rem 0.5rem;
  border-radius: var(--radius-sm);
  text-transform: uppercase;
  letter-spacing: 0.03em;
}

.tag-cli { background-color: var(--badge-cli-bg); color: var(--badge-cli-text); }
.tag-git { background-color: var(--badge-git-bg); color: var(--badge-git-text); }
.tag-scaffold { background-color: var(--badge-scaffold-bg); color: var(--badge-scaffold-text); }
.tag-tools { background-color: var(--badge-tools-bg); color: var(--badge-tools-text); }
.tag-default { background-color: var(--bg-subtle); color: var(--text-main); }

.difficulty-badge {
  font-size: 0.75rem;
  font-weight: 600;
  color: var(--text-muted);
  border: 1px solid var(--border-color);
  padding: 0.1rem 0.4rem;
  border-radius: var(--radius-sm);
}

.guide-title {
  font-size: 1.1rem;
  font-weight: 700;
  margin-bottom: 0.5rem;
}

.guide-prereqs {
  font-size: 0.85rem;
  color: var(--text-muted);
  margin-bottom: 1rem;
  background-color: var(--bg-subtle);
  padding: 0.5rem 0.75rem;
  border-radius: var(--radius-sm);
  border-left: 3px solid var(--border-strong);
}

.btn-primary {
  background-color: var(--accent-blue);
  color: var(--text-inverse);
  border: none;
  padding: 0.5rem 1rem;
  border-radius: var(--radius-sm);
  font-size: 0.875rem;
  font-weight: 600;
  cursor: pointer;
  width: 100%;
  text-align: center;
  transition: background-color var(--transition-fast);
}

.btn-primary:hover {
  background-color: var(--accent-blue-hover);
}

/* ==========================================
   Vault Resources Section
   ========================================== */
.resources-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(320px, 1fr));
  gap: 1.5rem;
}

.resource-card {
  background-color: var(--bg-surface);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  padding: 1.5rem;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
}

.resource-card:hover {
  border-color: var(--accent-green);
}

.resource-title {
  font-size: 1.1rem;
  font-weight: 700;
  margin-bottom: 0.5rem;
}

.resource-desc {
  font-size: 0.875rem;
  color: var(--text-muted);
  margin-bottom: 1rem;
}

.tags-wrapper {
  display: flex;
  flex-wrap: wrap;
  gap: 0.35rem;
  margin-bottom: 1rem;
}

.tag-item {
  font-size: 0.75rem;
  background-color: var(--bg-subtle);
  color: var(--text-muted);
  border: 1px solid var(--border-color);
  padding: 0.1rem 0.4rem;
  border-radius: var(--radius-sm);
  font-family: var(--font-mono);
}

.btn-secondary {
  background-color: transparent;
  color: var(--accent-green);
  border: 1px solid var(--accent-green);
  padding: 0.45rem 1rem;
  border-radius: var(--radius-sm);
  font-size: 0.875rem;
  font-weight: 600;
  cursor: pointer;
  text-decoration: none;
  display: inline-block;
  text-align: center;
  transition: background-color var(--transition-fast), color var(--transition-fast);
}

.btn-secondary:hover {
  background-color: var(--accent-green);
  color: var(--text-inverse);
}

/* Empty State */
.empty-state {
  grid-column: 1 / -1;
  text-align: center;
  padding: 3rem;
  background-color: var(--bg-surface);
  border: 1px dashed var(--border-color);
  border-radius: var(--radius-md);
  color: var(--text-muted);
}

/* ==========================================
   Join Us Section
   ========================================== */
.onboarding-flow {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 1.5rem;
  margin-bottom: 3rem;
}

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

.step-card {
  background-color: var(--bg-surface);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  padding: 2rem;
  position: relative;
}

.step-number-tag {
  font-size: 0.8rem;
  font-weight: 800;
  color: var(--accent-blue);
  text-transform: uppercase;
  letter-spacing: 0.05em;
  margin-bottom: 0.5rem;
}

.step-card-title {
  font-size: 1.25rem;
  font-weight: 700;
  margin-bottom: 1rem;
}

.step-card-body {
  font-size: 0.95rem;
  color: var(--text-muted);
  margin-bottom: 1.5rem;
}

.community-links-block {
  background-color: var(--bg-surface);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  padding: 2rem;
  text-align: center;
}

.community-btn-group {
  display: flex;
  justify-content: center;
  gap: 1rem;
  margin-top: 1.5rem;
  flex-wrap: wrap;
}

/* ==========================================
   About Us Section
   ========================================== */
.about-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 1.5rem;
}

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

.about-card {
  background-color: var(--bg-surface);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  padding: 2rem;
}

.hub-backlink-card {
  border-left: 4px solid var(--accent-blue);
}

.backlink-anchor {
  display: inline-block;
  margin-top: 1rem;
  font-weight: 700;
  color: var(--accent-blue);
  text-decoration: underline;
}

/* ==========================================
   Centralized Modal Window Overlay
   ========================================== */
.modal-overlay {
  display: none;
  position: fixed;
  top: 0;
  left: 0;
  width: 100vw;
  height: 100vh;
  background-color: var(--modal-backdrop);
  z-index: 300;
  align-items: center;
  justify-content: center;
  padding: 1rem;
}

.modal-overlay.active {
  display: flex;
}

.modal-container {
  background-color: var(--bg-surface);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  width: 100%;
  max-width: 640px;
  max-height: 85vh;
  display: flex;
  flex-direction: column;
  box-shadow: 0 10px 25px rgba(0, 0, 0, 0.2);
  animation: modalPop 0.2s ease-out;
}

@keyframes modalPop {
  from { opacity: 0; transform: scale(0.95); }
  to { opacity: 1; transform: scale(1); }
}

.modal-header {
  padding: 1.25rem 1.5rem;
  border-bottom: 1px solid var(--border-color);
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.modal-title {
  font-size: 1.25rem;
  font-weight: 700;
}

.modal-close-btn {
  background: transparent;
  border: 1px solid var(--border-color);
  color: var(--text-main);
  width: 32px;
  height: 32px;
  border-radius: var(--radius-sm);
  cursor: pointer;
  font-weight: bold;
}

.modal-body {
  padding: 1.5rem;
  overflow-y: auto;
  flex: 1;
}

/* Step-by-step instructions line breaks */
.guide-instructions {
  white-space: pre-line;
  font-family: var(--font-mono);
  font-size: 0.9rem;
  background-color: var(--bg-subtle);
  padding: 1rem;
  border-radius: var(--radius-sm);
  border: 1px solid var(--border-color);
  color: var(--text-main);
  line-height: 1.6;
}

.modal-footer {
  padding: 1rem 1.5rem;
  border-top: 1px solid var(--border-color);
  text-align: right;
}

/* Footer */
.site-footer {
  border-top: 1px solid var(--border-color);
  background-color: var(--bg-surface);
  padding: 2rem 0;
  text-align: center;
  font-size: 0.85rem;
  color: var(--text-muted);
  margin-top: auto;
  width: 100%;
  position: relative;
  z-index: 10;
}