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

html,
body {
  margin: 0;
  height: 100%;
}

body {
  font-family: system-ui, -apple-system, "Segoe UI", sans-serif;
  color: #2d3436;
  background: linear-gradient(135deg, #fff5f5, #fff9db, #e0f7fa, #fce4ec, #f3e5f5);
  background-size: 400% 400%;
  animation: bgShift 18s ease infinite;
}

@keyframes bgShift {
  0% { background-position: 0% 50%; }
  50% { background-position: 100% 50%; }
  100% { background-position: 0% 50%; }
}

.app {
  display: flex;
  flex-direction: column;
  min-height: 100dvh;
}

.header {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  padding: 0.75rem 1.25rem;
  flex-shrink: 0;
  color: #fff;
  background: linear-gradient(
    90deg,
    #ff6b6b,
    #feca57,
    #1dd1a1,
    #48dbfb,
    #ff9ff3,
    #ff6b6b
  );
  background-size: 300% 100%;
  animation: headerFlow 10s linear infinite;
  box-shadow: 0 4px 24px rgba(255, 107, 107, 0.35);
  position: relative;
  overflow: hidden;
}

.header::after {
  content: "";
  position: absolute;
  inset: 0;
  background: linear-gradient(
    105deg,
    transparent 40%,
    rgba(255, 255, 255, 0.25) 50%,
    transparent 60%
  );
  background-size: 200% 100%;
  animation: headerShine 6s ease-in-out infinite;
  pointer-events: none;
}

@keyframes headerFlow {
  0% { background-position: 0% 50%; }
  100% { background-position: 300% 50%; }
}

@keyframes headerShine {
  0%, 100% { background-position: 200% 0; }
  50% { background-position: -200% 0; }
}

.site-title {
  margin: 0;
  font-size: 1.25rem;
  font-weight: 800;
  letter-spacing: 0.04em;
  text-shadow: 0 2px 8px rgba(0, 0, 0, 0.15);
  position: relative;
  z-index: 1;
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.site-title-icon {
  display: inline-flex;
  animation: iconBounce 2s ease-in-out infinite;
}

@keyframes iconBounce {
  0%, 100% { transform: translateY(0) rotate(0deg); }
  25% { transform: translateY(-3px) rotate(-8deg); }
  75% { transform: translateY(-3px) rotate(8deg); }
}

.menu-toggle {
  display: flex;
  align-items: center;
  justify-content: center;
  min-width: 44px;
  min-height: 44px;
  padding: 0;
  border: 2px solid rgba(255, 255, 255, 0.7);
  border-radius: 12px;
  background: rgba(255, 255, 255, 0.25);
  backdrop-filter: blur(4px);
  color: #fff;
  font-size: 1.25rem;
  cursor: pointer;
  position: relative;
  z-index: 1;
  transition: transform 0.2s ease, background 0.2s ease;
}

.menu-toggle:hover {
  background: rgba(255, 255, 255, 0.4);
  transform: scale(1.05);
}

.menu-toggle:active {
  transform: scale(0.97);
}

.layout {
  display: flex;
  flex: 1;
  min-height: 0;
  position: relative;
}

.sidebar {
  width: 260px;
  flex-shrink: 0;
  overflow-y: auto;
  background: linear-gradient(180deg, #fff 0%, #fff9f0 40%, #f0f9ff 100%);
  border-right: 3px solid transparent;
  border-image: linear-gradient(180deg, #ff6b6b, #feca57, #48dbfb, #ff9ff3) 1;
  box-shadow: 4px 0 24px rgba(255, 107, 107, 0.12);
}

.sidebar-heading {
  margin: 0;
  padding: 1rem 1rem 0.5rem;
  font-size: 0.75rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.12em;
  background: linear-gradient(90deg, #ff6b6b, #feca57, #48dbfb);
  background-size: 200% auto;
  -webkit-background-clip: text;
  background-clip: text;
  -webkit-text-fill-color: transparent;
  animation: labelShimmer 4s linear infinite;
}

@keyframes labelShimmer {
  0% { background-position: 0% center; }
  100% { background-position: 200% center; }
}

.game-list {
  list-style: none;
  margin: 0;
  padding: 0.5rem;
}

.game-list li {
  margin-bottom: 0.375rem;
}

.game-link {
  display: flex;
  align-items: center;
  gap: 0.625rem;
  min-height: 44px;
  width: 100%;
  padding: 0.625rem 0.875rem;
  border: 2px solid transparent;
  border-radius: 12px;
  background: rgba(255, 255, 255, 0.7);
  color: #2d3436;
  font: inherit;
  font-weight: 600;
  text-align: left;
  cursor: pointer;
  transition: transform 0.2s ease, box-shadow 0.2s ease, border-color 0.2s ease;
  box-shadow: 0 2px 8px rgba(0, 0, 0, 0.04);
}

.game-link::before {
  content: "▶";
  font-size: 0.625rem;
  opacity: 0.4;
  transition: opacity 0.2s ease, transform 0.2s ease;
}

.game-list li:nth-child(4n + 1) .game-link:hover {
  border-color: #ff6b6b;
  box-shadow: 0 4px 16px rgba(255, 107, 107, 0.25);
}

.game-list li:nth-child(4n + 2) .game-link:hover {
  border-color: #feca57;
  box-shadow: 0 4px 16px rgba(254, 202, 87, 0.35);
}

.game-list li:nth-child(4n + 3) .game-link:hover {
  border-color: #48dbfb;
  box-shadow: 0 4px 16px rgba(72, 219, 251, 0.3);
}

.game-list li:nth-child(4n + 4) .game-link:hover {
  border-color: #ff9ff3;
  box-shadow: 0 4px 16px rgba(255, 159, 243, 0.3);
}

.game-link:hover {
  transform: translateX(4px);
  background: #fff;
}

.game-link:hover::before {
  opacity: 1;
  transform: translateX(2px);
}

.game-link.is-active {
  color: #fff;
  border-color: transparent;
  background: linear-gradient(135deg, #ff6b6b, #feca57, #48dbfb);
  background-size: 200% 200%;
  animation: activePulse 4s ease infinite;
  box-shadow: 0 4px 20px rgba(255, 107, 107, 0.35);
}

.game-link.is-active::before {
  opacity: 1;
  color: #fff;
}

@keyframes activePulse {
  0%, 100% { background-position: 0% 50%; }
  50% { background-position: 100% 50%; }
}

.game-link:disabled {
  opacity: 0.5;
  cursor: default;
}

.main {
  flex: 1;
  min-width: 0;
  min-height: 0;
  display: flex;
  flex-direction: column;
  background: rgba(255, 255, 255, 0.45);
  backdrop-filter: blur(8px);
}

.welcome {
  flex: 1;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  padding: 2rem;
  text-align: center;
}

.welcome-title {
  margin: 0 0 0.75rem;
  font-size: clamp(1.25rem, 4vw, 1.75rem);
  font-weight: 800;
  background: linear-gradient(90deg, #ff6b6b, #feca57, #1dd1a1, #48dbfb);
  background-size: 300% auto;
  -webkit-background-clip: text;
  background-clip: text;
  -webkit-text-fill-color: transparent;
  animation: labelShimmer 6s linear infinite;
}

.welcome-text {
  margin: 0;
  color: #636e72;
  max-width: 28rem;
  line-height: 1.7;
  font-size: 0.9375rem;
}

.game-frame {
  flex: 1;
  width: 100%;
  border: none;
  background: #000;
}

.game-frame[hidden],
.welcome[hidden] {
  display: none;
}

.overlay {
  display: none;
  position: fixed;
  inset: 0;
  top: 57px;
  background: rgba(45, 52, 54, 0.35);
  backdrop-filter: blur(2px);
  z-index: 10;
}

.overlay.is-visible {
  display: block;
}

.status-message {
  padding: 1rem;
  color: #636e72;
  font-size: 0.875rem;
}

@media (max-width: 767px) {
  .menu-toggle {
    display: flex;
  }

  .sidebar {
    position: fixed;
    top: 57px;
    left: 0;
    bottom: 0;
    z-index: 20;
    transform: translateX(-100%);
    transition: transform 0.25s cubic-bezier(0.4, 0, 0.2, 1);
    box-shadow: 8px 0 32px rgba(255, 107, 107, 0.2);
  }

  .sidebar.is-open {
    transform: translateX(0);
  }
}

@media (min-width: 768px) {
  .menu-toggle {
    display: none;
  }

  .overlay {
    display: none !important;
  }
}

@media (prefers-reduced-motion: reduce) {
  body,
  .header,
  .header::after,
  .site-title-icon,
  .sidebar-heading,
  .game-link.is-active,
  .welcome-title {
    animation: none;
  }

  .game-link,
  .menu-toggle {
    transition: none;
  }
}