/* Shared professional site navigation — React app + static HTML pages */

.app-topnav {
  position: sticky;
  top: 0;
  z-index: 1000;
  width: 100%;
  background: linear-gradient(180deg, #0c1929 0%, #0f2340 100%);
  border-bottom: 1px solid rgba(88, 166, 255, 0.18);
  box-shadow: 0 4px 24px rgba(0, 0, 0, 0.35);
  font-family: 'Sora', 'Inter', -apple-system, BlinkMacSystemFont, sans-serif;
}

.app-topnav::before {
  content: '';
  display: block;
  height: 2px;
  background: linear-gradient(90deg, transparent, rgba(88, 166, 255, 0.7) 30%, rgba(63, 185, 80, 0.7) 70%, transparent);
}

.app-topnav-inner {
  max-width: 1400px;
  margin: 0 auto;
  display: flex;
  align-items: center;
  height: 64px;
  padding: 0 24px;
  gap: 8px;
}

.app-topnav-brand {
  display: flex;
  align-items: center;
  gap: 10px;
  color: #ffffff;
  cursor: pointer;
  flex-shrink: 0;
  margin-right: 8px;
  text-decoration: none;
}

.app-topnav-brand img {
  height: 36px;
  width: 36px;
  object-fit: contain;
  border-radius: 8px;
  box-shadow: 0 0 12px rgba(88, 166, 255, 0.25);
}

.app-topnav-brand-text {
  display: flex;
  flex-direction: column;
  line-height: 1.15;
}

.app-topnav-brand-name {
  font-weight: 800;
  font-size: 15px;
  letter-spacing: -0.2px;
  color: #ffffff;
}

.app-topnav-brand-tag {
  font-size: 10px;
  font-weight: 600;
  letter-spacing: 0.6px;
  text-transform: uppercase;
  color: rgba(88, 166, 255, 0.9);
}

.app-topnav-desktop {
  display: flex;
  align-items: center;
  gap: 2px;
  flex: 1;
  margin-left: 12px;
}

.app-topnav-link {
  color: rgba(255, 255, 255, 0.82);
  text-decoration: none;
  font-size: 13.5px;
  font-weight: 600;
  padding: 8px 12px;
  border-radius: 8px;
  white-space: nowrap;
  transition: color 0.18s, background 0.18s;
  border: none;
  background: transparent;
  font-family: inherit;
  cursor: pointer;
}

.app-topnav-link:hover,
.app-topnav-dropdown:hover .app-topnav-trigger {
  color: #ffffff;
  background: rgba(255, 255, 255, 0.08);
}

.app-topnav-link.active,
.app-topnav-trigger.active {
  color: #ffffff;
  background: rgba(88, 166, 255, 0.15);
}

.app-topnav-dropdown {
  position: relative;
}

.app-topnav-trigger {
  display: inline-flex;
  align-items: center;
  gap: 5px;
}

.app-topnav-chevron {
  opacity: 0.7;
  transition: transform 0.2s;
}

.app-topnav-dropdown.open .app-topnav-chevron,
.app-topnav-dropdown:hover .app-topnav-chevron {
  transform: rotate(180deg);
}

.app-topnav-panel {
  position: absolute;
  top: calc(100% + 8px);
  left: 0;
  min-width: 280px;
  background: #111a2e;
  border: 1px solid rgba(88, 166, 255, 0.22);
  border-radius: 12px;
  box-shadow: 0 16px 48px rgba(0, 0, 0, 0.45);
  padding: 16px;
  opacity: 0;
  visibility: hidden;
  transform: translateY(6px);
  transition: opacity 0.2s, transform 0.2s, visibility 0.2s;
  pointer-events: none;
}

/* Create invisible hover bridge between trigger and panel */
.app-topnav-dropdown::after {
  content: '';
  position: absolute;
  top: 100%;
  left: 0;
  right: 0;
  height: 8px;
  pointer-events: auto;
}

.app-topnav-dropdown.open .app-topnav-panel,
.app-topnav-dropdown:hover .app-topnav-panel {
  opacity: 1;
  visibility: visible;
  transform: translateY(0);
  pointer-events: auto;
}

.app-topnav-panel--mega {
  min-width: 880px;
  left: -120px;
  padding: 22px 24px 14px;
}

.app-topnav-panel-title {
  font-size: 11px;
  font-weight: 700;
  letter-spacing: 1px;
  text-transform: uppercase;
  color: rgba(88, 166, 255, 0.85);
  margin: 0 0 12px;
}

.app-topnav-compiler-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 4px;
}

.app-topnav-compiler-item {
  color: rgba(255, 255, 255, 0.85);
  text-decoration: none;
  font-size: 13px;
  font-weight: 600;
  padding: 8px 12px;
  border-radius: 8px;
  transition: background 0.15s, color 0.15s;
}

.app-topnav-compiler-item:hover {
  background: rgba(88, 166, 255, 0.12);
  color: #ffffff;
}

.app-topnav-compiler-item.active {
  background: rgba(88, 166, 255, 0.2);
  color: #58a6ff;
}

.app-topnav-mega-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 20px 24px;
}

.app-topnav-mega-title {
  font-size: 10.5px;
  font-weight: 700;
  letter-spacing: 0.8px;
  text-transform: uppercase;
  color: #58a6ff;
  margin: 0 0 8px;
  padding-bottom: 6px;
  border-bottom: 1px solid rgba(88, 166, 255, 0.2);
}

.app-topnav-mega-link {
  display: block;
  color: rgba(255, 255, 255, 0.78);
  text-decoration: none;
  font-size: 12.5px;
  font-weight: 500;
  padding: 5px 0;
  transition: color 0.15s;
}

.app-topnav-mega-link:hover,
.app-topnav-mega-link.active {
  color: #ffffff;
}

.app-topnav-mega-footer {
  display: block;
  margin-top: 14px;
  padding-top: 12px;
  border-top: 1px solid rgba(255, 255, 255, 0.1);
  color: #58a6ff;
  font-size: 13px;
  font-weight: 700;
  text-decoration: none;
}

.app-topnav-mega-footer:hover {
  color: #79b8ff;
}

.app-topnav-actions {
  display: flex;
  align-items: center;
  gap: 8px;
  margin-left: auto;
  flex-shrink: 0;
}

.app-topnav-cta {
  background: linear-gradient(135deg, #238636 0%, #2ea043 100%);
  color: #ffffff;
  text-decoration: none;
  font-size: 13px;
  font-weight: 700;
  padding: 8px 16px;
  border-radius: 8px;
  white-space: nowrap;
  transition: transform 0.18s, box-shadow 0.18s;
  box-shadow: 0 2px 12px rgba(35, 134, 54, 0.35);
}

.app-topnav-cta:hover {
  transform: translateY(-1px);
  box-shadow: 0 4px 18px rgba(35, 134, 54, 0.45);
}

.app-topnav-toggle {
  background: rgba(255, 255, 255, 0.08);
  color: #ffffff;
  border: 1px solid rgba(255, 255, 255, 0.18);
  border-radius: 8px;
  padding: 7px 10px;
  font-size: 14px;
  cursor: pointer;
  transition: background 0.18s, border-color 0.18s;
  font-family: inherit;
}

.app-topnav-toggle:hover {
  background: rgba(255, 255, 255, 0.15);
  border-color: rgba(255, 255, 255, 0.35);
}

.app-topnav-hamburger {
  display: none;
  flex-direction: column;
  justify-content: center;
  gap: 5px;
  width: 36px;
  height: 36px;
  background: rgba(255, 255, 255, 0.08);
  border: 1px solid rgba(255, 255, 255, 0.18);
  border-radius: 8px;
  padding: 8px;
  cursor: pointer;
}

.app-topnav-hamburger span {
  display: block;
  height: 2px;
  background: #ffffff;
  border-radius: 2px;
}

.app-topnav-mobile {
  display: none;
  background: #0c1929;
  border-top: 1px solid rgba(88, 166, 255, 0.15);
  padding: 16px 24px 24px;
  max-height: calc(100vh - 64px);
  overflow-y: auto;
}

.app-topnav.app-topnav--mobile-open .app-topnav-mobile {
  display: block;
}

.app-topnav-mobile-link {
  display: block;
  color: rgba(255, 255, 255, 0.9);
  text-decoration: none;
  font-size: 15px;
  font-weight: 600;
  padding: 12px 0;
  border-bottom: 1px solid rgba(255, 255, 255, 0.08);
}

.app-topnav-mobile-heading {
  font-size: 11px;
  font-weight: 700;
  letter-spacing: 1px;
  text-transform: uppercase;
  color: #58a6ff;
  margin: 16px 0 10px;
}

.app-topnav-mobile-grid {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin-bottom: 8px;
}

.app-topnav-mobile-chip {
  color: #ffffff;
  text-decoration: none;
  font-size: 12.5px;
  font-weight: 600;
  padding: 6px 12px;
  border-radius: 999px;
  background: rgba(88, 166, 255, 0.12);
  border: 1px solid rgba(88, 166, 255, 0.25);
}

.app-topnav-mobile-cta {
  display: block;
  margin-top: 16px;
  text-align: center;
  background: linear-gradient(135deg, #238636, #2ea043);
  color: #ffffff;
  text-decoration: none;
  font-size: 15px;
  font-weight: 700;
  padding: 12px;
  border-radius: 10px;
}

/* Hide legacy cramped nav when site-nav is active */
nav.topnav,
header.header,
.blog-topnav,
nav.topnav.site-nav-replaced,
header.header.site-nav-replaced,
.app-subnav {
  display: none !important;
}

/* ═══════════════════════════════════════════════
   TUTORIAL SINGLE MAIN HEADER MODE
   ═══════════════════════════════════════════════ */
.app-topnav--tutorial .app-topnav-inner {
  height: 56px;
  padding: 0 16px;
  max-width: 100%;
}

.app-topnav-tutorial-nav {
  display: flex;
  align-items: center;
  gap: 2px;
  overflow-x: auto;
  scrollbar-width: none;
  -ms-overflow-style: none;
  flex: 1;
  margin: 0 12px;
  height: 100%;
}

.app-topnav-tutorial-nav::-webkit-scrollbar {
  display: none;
}

.app-topnav-tut-item {
  color: rgba(255, 255, 255, 0.78);
  text-decoration: none;
  font-size: 13.5px;
  font-weight: 600;
  padding: 0 13px;
  height: 56px;
  display: inline-flex;
  align-items: center;
  border-bottom: 3px solid transparent;
  white-space: nowrap;
  transition: color 0.15s, background 0.15s, border-bottom-color 0.15s;
  flex-shrink: 0;
}

.app-topnav-tut-item:hover {
  color: #ffffff;
  background: rgba(255, 255, 255, 0.08);
}

.app-topnav-tut-item.active {
  color: #ffffff;
  background: rgba(88, 166, 255, 0.18);
  border-bottom-color: #ff9900;
  font-weight: 700;
}

body.light-theme .app-topnav--tutorial {
  background: #ffffff;
  border-bottom-color: #d0d7de;
  box-shadow: 0 1px 6px rgba(0, 0, 0, 0.08);
}

body.light-theme .app-topnav--tutorial .app-topnav-brand-name {
  color: #1f2328;
}

body.light-theme .app-topnav-tut-item {
  color: #57606a;
}

body.light-theme .app-topnav-tut-item:hover {
  color: #1f2328;
  background: rgba(0, 0, 0, 0.05);
}

body.light-theme .app-topnav-tut-item.active {
  color: #0969da;
  background: rgba(9, 105, 218, 0.08);
  border-bottom-color: #ff9900;
}

/* ═══════════════════════════════════════════════
   SIDEBAR 4-MODE ICON BUTTONS WITH HOVER TOOLTIPS
   1. Tutorials  2. Problems  3. Quiz  4. Compiler
   ═══════════════════════════════════════════════ */
.sidebar-modes-bar {
  display: none !important;
}

.sidebar .sidebar-modes-bar a.sidebar-mode-box,
.sidebar a.sidebar-mode-box,
.sidebar-mode-box {
  position: relative !important;
  display: flex !important;
  align-items: center !important;
  justify-content: center !important;
  height: 42px !important;
  padding: 0 !important;
  background: rgba(255, 255, 255, 0.04) !important;
  border: 1px solid rgba(88, 166, 255, 0.18) !important;
  border-radius: 10px !important;
  text-decoration: none !important;
  color: rgba(255, 255, 255, 0.75) !important;
  cursor: pointer !important;
  transition: all 0.2s cubic-bezier(0.4, 0, 0.2, 1) !important;
  user-select: none !important;
  margin: 0 !important;
  min-width: 0 !important;
  box-sizing: border-box !important;
}

.sidebar-mode-box svg {
  transition: transform 0.2s ease, stroke 0.2s ease !important;
  pointer-events: none !important;
}

.sidebar .sidebar-modes-bar a.sidebar-mode-box:hover,
.sidebar a.sidebar-mode-box:hover,
.sidebar-mode-box:hover {
  background: rgba(88, 166, 255, 0.15) !important;
  border-color: rgba(88, 166, 255, 0.5) !important;
  color: #58a6ff !important;
  transform: translateY(-2px) !important;
  box-shadow: 0 4px 14px rgba(88, 166, 255, 0.2) !important;
}

.sidebar .sidebar-modes-bar a.sidebar-mode-box:hover svg,
.sidebar-mode-box:hover svg {
  transform: scale(1.15) !important;
}

.sidebar .sidebar-modes-bar a.sidebar-mode-box.active,
.sidebar a.sidebar-mode-box.active,
.sidebar-mode-box.active {
  background: linear-gradient(135deg, rgba(35, 134, 54, 0.35) 0%, rgba(46, 160, 67, 0.5) 100%) !important;
  border-color: #3fb950 !important;
  color: #ffffff !important;
  box-shadow: 0 0 14px rgba(63, 185, 80, 0.3) !important;
}

/* Sleek Floating Tooltip on Hover */
.sidebar-mode-box .mode-tooltip {
  position: absolute !important;
  top: calc(100% + 7px) !important;
  bottom: auto !important;
  left: 50% !important;
  transform: translateX(-50%) translateY(-4px) !important;
  background: #161b22 !important;
  color: #ffffff !important;
  font-size: 11px !important;
  font-weight: 700 !important;
  letter-spacing: 0.3px !important;
  padding: 5px 9px !important;
  border-radius: 6px !important;
  white-space: nowrap !important;
  pointer-events: none !important;
  opacity: 0 !important;
  visibility: hidden !important;
  transition: all 0.18s cubic-bezier(0.4, 0, 0.2, 1) !important;
  border: 1px solid rgba(88, 166, 255, 0.35) !important;
  box-shadow: 0 6px 18px rgba(0, 0, 0, 0.5) !important;
  z-index: 1000 !important;
  line-height: 1 !important;
}

.sidebar-mode-box .mode-tooltip::after {
  content: '' !important;
  position: absolute !important;
  bottom: 100% !important;
  top: auto !important;
  left: 50% !important;
  transform: translateX(-50%) !important;
  border: 4px solid transparent !important;
  border-bottom-color: #161b22 !important;
}

.sidebar-mode-box:hover .mode-tooltip {
  opacity: 1 !important;
  visibility: visible !important;
  transform: translateX(-50%) translateY(0) !important;
}

body.light-theme .sidebar-modes-bar {
  border-bottom-color: #d0d7de !important;
}

body.light-theme .sidebar .sidebar-modes-bar a.sidebar-mode-box,
body.light-theme .sidebar a.sidebar-mode-box,
body.light-theme .sidebar-mode-box {
  background: #f6f8fa !important;
  border-color: #d0d7de !important;
  color: #57606a !important;
}

body.light-theme .sidebar .sidebar-modes-bar a.sidebar-mode-box:hover,
body.light-theme .sidebar a.sidebar-mode-box:hover,
body.light-theme .sidebar-mode-box:hover {
  background: #ffffff !important;
  color: #0969da !important;
  border-color: #0969da !important;
  box-shadow: 0 4px 12px rgba(9, 105, 218, 0.15) !important;
}

body.light-theme .sidebar .sidebar-modes-bar a.sidebar-mode-box.active,
body.light-theme .sidebar a.sidebar-mode-box.active,
body.light-theme .sidebar-mode-box.active {
  background: #dafbe1 !important;
  border-color: #1a7f37 !important;
  color: #1a7f37 !important;
  box-shadow: 0 2px 8px rgba(26, 127, 55, 0.18) !important;
}

body.light-theme .sidebar-mode-box .mode-tooltip {
  background: #24292f !important;
  color: #ffffff !important;
  border-color: #424a53 !important;
}

body.light-theme .sidebar-mode-box .mode-tooltip::after {
  border-bottom-color: #24292f !important;
  border-top-color: transparent !important;
}

@media (max-width: 1100px) {
  .app-topnav-desktop { display: none; }
  .app-topnav-cta { display: none; }
  .app-topnav-hamburger { display: flex; }
  .app-topnav-brand-tag { display: none; }
  .app-topnav-panel--mega {
    min-width: min(94vw, 880px);
    left: -20px;
    grid-template-columns: repeat(2, 1fr);
  }
}

@media (max-width: 768px) {
  .app-topnav-cta { display: none; }
}

@media (max-width: 480px) {
  .app-topnav-inner { padding: 0 12px; }
  .app-topnav-brand-name { font-size: 13.5px; }
  .app-topnav-brand img { height: 28px; width: 28px; }
  .app-topnav-tut-item { padding: 0 10px; font-size: 12.5px; }
}