/* ============================================
   C++ АКАДЕМІЯ — LAYOUT CSS
   ============================================ */

/* ---- APP SHELL ---- */
.sidebar {
  width: var(--sidebar-width);
  height: 100vh;
  position: fixed;
  top: 0; left: 0;
  background: var(--bg-secondary);
  border-right: 1px solid var(--border-subtle);
  display: flex;
  flex-direction: column;
  z-index: 100;
  transition: transform 0.3s cubic-bezier(0.4,0,0.2,1);
  overflow-y: auto;
  overflow-x: hidden;
}

.main-content {
  margin-left: var(--sidebar-width);
  min-height: 100vh;
  padding: 2.5rem 3rem;
  max-width: 1200px;
  width: 100%;
}

/* ---- SIDEBAR BRAND ---- */
.sidebar-brand {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  padding: 1.5rem 1.5rem 1rem;
  border-bottom: 1px solid var(--border-subtle);
  margin-bottom: 0.5rem;
}
.brand-icon {
  width: 40px; height: 40px;
  background: var(--gradient-btn);
  border-radius: var(--radius-sm);
  display: flex; align-items: center; justify-content: center;
  font-size: 1.2rem;
  box-shadow: var(--shadow-btn);
}
.brand-name {
  font-size: 1rem;
  font-weight: 800;
  background: var(--gradient-hero);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  white-space: nowrap;
}

/* ---- SIDEBAR NAV ---- */
.sidebar-nav {
  flex: 1;
  padding: 0.5rem 0.75rem;
  display: flex;
  flex-direction: column;
  gap: 0.2rem;
}
.nav-link {
  display: flex;
  align-items: center;
  gap: 0.875rem;
  padding: 0.75rem 1rem;
  border-radius: var(--radius-md);
  font-size: 0.9rem;
  font-weight: 500;
  color: var(--text-secondary);
  transition: var(--transition);
  white-space: nowrap;
}
.nav-link:hover {
  background: var(--bg-glass);
  color: var(--text-primary);
}
.nav-link.active {
  background: rgba(99,102,241,0.14);
  color: var(--accent-blue);
  font-weight: 600;
  box-shadow: inset 3px 0 0 var(--accent-blue);
}
.nav-icon { font-size: 1.1rem; flex-shrink: 0; }
.nav-label { flex: 1; }

/* ---- SIDEBAR BOTTOM ---- */
.sidebar-bottom {
  padding: 1rem 0.75rem 1.25rem;
  border-top: 1px solid var(--border-subtle);
}
.theme-toggle {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  padding: 0.65rem 1rem;
  border-radius: var(--radius-md);
  width: 100%;
  color: var(--text-secondary);
  font-size: 0.9rem;
  font-weight: 500;
  transition: var(--transition);
}
.theme-toggle:hover { background: var(--bg-glass); color: var(--text-primary); }
.theme-icon-light { display: none; }
[data-theme="light"] .theme-icon-dark  { display: none; }
[data-theme="light"] .theme-icon-light { display: inline; }

/* ---- SIDEBAR XP ---- */
.sidebar-xp {
  padding: 0.75rem 1rem;
  background: var(--bg-glass);
  border-radius: var(--radius-md);
  margin-top: 0.5rem;
}
.xp-label {
  font-size: 0.8rem;
  color: var(--text-muted);
  margin-bottom: 0.4rem;
  font-weight: 600;
}
.xp-label span { color: var(--accent-orange); }
.xp-mini-bar {
  height: 4px;
  background: var(--bg-tertiary);
  border-radius: 2px;
  overflow: hidden;
}
.xp-mini-fill {
  height: 100%;
  background: linear-gradient(90deg, var(--accent-orange), var(--accent-pink));
  border-radius: 2px;
  transition: width 0.6s ease;
}

/* ---- MOBILE HEADER ---- */
.mobile-header {
  display: none;
  position: fixed;
  top: 0; left: 0; right: 0;
  height: 56px;
  background: var(--bg-secondary);
  border-bottom: 1px solid var(--border-subtle);
  align-items: center;
  justify-content: space-between;
  padding: 0 1rem;
  z-index: 200;
  backdrop-filter: blur(16px);
}
.mobile-brand {
  font-weight: 800;
  font-size: 0.95rem;
  background: var(--gradient-hero);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}
.mobile-menu-btn, .theme-toggle-mobile {
  width: 36px; height: 36px;
  display: flex; align-items: center; justify-content: center;
  border-radius: var(--radius-sm);
  color: var(--text-primary);
  font-size: 1.1rem;
  transition: var(--transition);
}
.mobile-menu-btn:hover, .theme-toggle-mobile:hover { background: var(--bg-glass); }

.mobile-overlay {
  display: none;
  position: fixed;
  inset: 0;
  background: rgba(0,0,0,0.6);
  backdrop-filter: blur(4px);
  z-index: 99;
}
.mobile-overlay.active { display: block; }

/* ---- GRID LAYOUTS ---- */
.grid-2 { display: grid; grid-template-columns: repeat(2, 1fr); gap: 1.5rem; }
.grid-3 { display: grid; grid-template-columns: repeat(3, 1fr); gap: 1.5rem; }
.grid-4 { display: grid; grid-template-columns: repeat(4, 1fr); gap: 1.25rem; }
.grid-auto { display: grid; grid-template-columns: repeat(auto-fill, minmax(280px, 1fr)); gap: 1.5rem; }

/* ---- LESSON DETAIL LAYOUT ---- */
.lesson-layout {
  display: grid;
  grid-template-columns: 1fr 340px;
  gap: 2rem;
  align-items: start;
}
.lesson-sidebar-sticky { position: sticky; top: 2rem; }

/* ---- PAGE ANIMATIONS ---- */
.page-enter {
  animation: fadeIn 0.4s ease forwards;
}

/* ---- HERO SECTION ---- */
.hero-section {
  position: relative;
  min-height: 85vh;
  display: flex;
  flex-direction: column;
  justify-content: center;
  overflow: hidden;
  padding: 4rem 0;
}
.hero-bg {
  position: absolute;
  inset: 0;
  pointer-events: none;
}
.hero-orb {
  position: absolute;
  border-radius: 50%;
  filter: blur(80px);
  opacity: 0.35;
}
.hero-orb-1 {
  width: 500px; height: 500px;
  background: radial-gradient(circle, #6366f1, transparent);
  top: -100px; left: -100px;
  animation: orbFloat1 8s ease-in-out infinite;
}
.hero-orb-2 {
  width: 400px; height: 400px;
  background: radial-gradient(circle, #8b5cf6, transparent);
  bottom: -80px; right: -80px;
  animation: orbFloat2 10s ease-in-out infinite;
}
.hero-orb-3 {
  width: 300px; height: 300px;
  background: radial-gradient(circle, #22d3ee, transparent);
  top: 40%; right: 20%;
  animation: orbFloat3 12s ease-in-out infinite;
}
.hero-content { position: relative; z-index: 1; }
.hero-tag {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.4rem 1rem;
  background: rgba(99,102,241,0.15);
  border: 1px solid rgba(99,102,241,0.35);
  border-radius: var(--radius-full);
  font-size: 0.85rem;
  font-weight: 600;
  color: var(--accent-blue);
  margin-bottom: 1.5rem;
  animation: slideDown 0.6s ease 0.1s both;
}
.hero-title { animation: fadeIn 0.6s ease 0.2s both; }
.hero-desc  { animation: fadeIn 0.6s ease 0.35s both; max-width: 600px; font-size: 1.1rem; margin: 1.25rem 0 2rem; }
.hero-cta   { animation: fadeIn 0.6s ease 0.5s both; display: flex; gap: 1rem; flex-wrap: wrap; }
.hero-stats {
  animation: fadeIn 0.6s ease 0.65s both;
  display: flex;
  gap: 2.5rem;
  margin-top: 3rem;
  flex-wrap: wrap;
}
.hero-stat-item .hero-stat-num {
  font-size: 2rem;
  font-weight: 800;
  background: var(--gradient-hero);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  line-height: 1;
}
.hero-stat-item .hero-stat-label {
  font-size: 0.8rem;
  color: var(--text-muted);
  margin-top: 0.2rem;
}

/* ---- FEATURES GRID ---- */
.feature-card {
  padding: 1.75rem;
  background: var(--bg-glass);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-lg);
  transition: var(--transition);
}
.feature-card:hover {
  border-color: var(--border-color);
  background: var(--bg-glass-hover);
  transform: translateY(-3px);
}
.feature-icon {
  font-size: 2rem;
  margin-bottom: 1rem;
}
.feature-card h4 { margin-bottom: 0.4rem; }

/* ---- RESPONSIVE BREAKPOINTS ---- */
@media (max-width: 1100px) {
  .main-content  { padding: 2rem; }
  .lesson-layout { grid-template-columns: 1fr; }
  .lesson-sidebar-sticky { position: static; }
  .grid-4        { grid-template-columns: repeat(2, 1fr); }
}

@media (max-width: 900px) {
  .sidebar { transform: translateX(-100%); }
  .sidebar.open { transform: translateX(0); }
  .main-content { margin-left: 0; padding: 1.25rem; padding-top: 4.5rem; }
  .mobile-header { display: flex; }
  .grid-2 { grid-template-columns: 1fr; }
  .grid-3 { grid-template-columns: 1fr; }
  .hero-stats { gap: 1.5rem; }
}

@media (max-width: 640px) {
  .hero-section    { min-height: 70vh; padding: 2rem 0; }
  .main-content    { padding: 1rem; padding-top: 4.5rem; }
  .grid-4          { grid-template-columns: repeat(2, 1fr); }
  .hero-cta        { flex-direction: column; }
  .hero-cta .btn   { width: 100%; justify-content: center; }
  .toast-container { right: 0.75rem; left: 0.75rem; }
  .toast           { max-width: 100%; }
}