:root {
  --bg-1: #0b1220;
  --bg-2: #1f2937;
  --card: rgba(255, 255, 255, 0.08);
  --card-border: rgba(255, 255, 255, 0.14);
  --text: rgba(255, 255, 255, 0.92);
  --muted: rgba(255, 255, 255, 0.65);
  --shadow: rgba(0, 0, 0, 0.35);
  --ring: rgba(99, 102, 241, 0.55);
  --ring-strong: rgba(99, 102, 241, 0.9);
  --success: rgba(34, 197, 94, 0.35);
  --error: rgba(239, 68, 68, 0.35);
  --warning: rgba(245, 158, 11, 0.35);

  --radius-xl: 20px;
  --radius-lg: 14px;
  --radius-md: 12px;
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  min-height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
  font-family: "Segoe UI", Tahoma, Geneva, Verdana, sans-serif;
  color: var(--text);

  background:
    radial-gradient(
      1200px 600px at 20% 10%,
      rgba(99, 102, 241, 0.35),
      transparent 55%
    ),
    radial-gradient(
      900px 500px at 90% 40%,
      rgba(16, 185, 129, 0.25),
      transparent 55%
    ),
    linear-gradient(90deg, var(--bg-2), var(--bg-1));
  overflow-x: hidden;
  animation: bgShift 10s ease-in-out infinite;
}

@keyframes bgShift {
  0% {
    filter: hue-rotate(0deg);
  }
  50% {
    filter: hue-rotate(12deg);
  }
  100% {
    filter: hue-rotate(0deg);
  }
}

h1 {
  margin: 0;
  font-size: 28px;
  letter-spacing: 0.2px;
  text-align: center;
  line-height: 1.2;

  background: linear-gradient(
    90deg,
    rgba(99, 102, 241, 1),
    rgba(16, 185, 129, 1),
    rgba(236, 72, 153, 1)
  );
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;

  animation: titleFloat 3.5s ease-in-out infinite;
}

@keyframes titleFloat {
  0%,
  100% {
    transform: translateY(0);
  }
  50% {
    transform: translateY(-4px);
  }
}

#game-box {
  width: min(360px, 92vw);
  padding: 26px 22px;
  border-radius: var(--radius-xl);

  background: var(--card);
  border: 1px solid var(--card-border);
  backdrop-filter: blur(14px);

  box-shadow:
    0 20px 60px var(--shadow),
    inset 0 1px 0 rgba(255, 255, 255, 0.08);

  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 14px;

  transform: translateY(0);
  transition:
    transform 220ms ease,
    box-shadow 220ms ease,
    border-color 220ms ease;
}

#game-box:hover {
  transform: translateY(-6px);
  border-color: rgba(255, 255, 255, 0.22);
  box-shadow:
    0 30px 80px rgba(0, 0, 0, 0.45),
    inset 0 1px 0 rgba(255, 255, 255, 0.1);
}

#noInput {
  padding: 16px 14px;
  border-radius: var(--radius-lg);
  width: 100%;

  background: rgba(0, 0, 0, 0.25);
  border: 1px solid rgba(255, 255, 255, 0.18);
  color: var(--text);

  outline: none;

  transition:
    border-color 180ms ease,
    box-shadow 180ms ease,
    transform 180ms ease;
}

#noInput:focus {
  border-color: rgba(99, 102, 241, 0.65);
  box-shadow: 0 0 0 4px var(--ring);
  transform: translateY(-1px);
}

#noInput::placeholder {
  color: rgba(255, 255, 255, 0.55);
}

#Submit {
  width: 100%;
  padding: 14px 16px;
  border-radius: var(--radius-lg);

  border: 0;
  cursor: pointer;

  color: rgba(255, 255, 255, 0.95);
  font-size: 18px;
  font-weight: 650;
  letter-spacing: 0.2px;

  background: linear-gradient(
    90deg,
    rgba(99, 102, 241, 0.95),
    rgba(16, 185, 129, 0.9)
  );
  box-shadow:
    0 14px 26px rgba(99, 102, 241, 0.25),
    inset 0 1px 0 rgba(255, 255, 255, 0.18);

  transform: translateY(0);
  transition:
    transform 160ms ease,
    filter 160ms ease,
    box-shadow 160ms ease;
}

#Submit:hover {
  filter: brightness(1.05) saturate(1.05);
  transform: translateY(-2px);
  box-shadow:
    0 18px 34px rgba(99, 102, 241, 0.32),
    inset 0 1px 0 rgba(255, 255, 255, 0.22);
}

#Submit:active {
  transform: translateY(0);
  filter: brightness(0.98);
}

#message {
  margin-top: 2px;
  width: 100%;

  padding: 12px 14px;
  border-radius: var(--radius-md);

  font-size: 16px;
  text-align: center;

  background-color: rgba(255, 255, 255, 0.08);
  border: 1px solid rgba(255, 255, 255, 0.14);

  opacity: 0;
  transform: translateY(8px) scale(0.99);
  transition:
    opacity 220ms ease,
    transform 220ms ease;

  display: block; /* keep measurable; we'll control visibility via opacity */
  pointer-events: none;
}

#message.is-visible {
  opacity: 1;
  transform: translateY(0) scale(1);
  animation: popIn 260ms ease-out;
}

@keyframes popIn {
  from {
    opacity: 0;
    transform: translateY(10px) scale(0.98);
  }
  to {
    opacity: 1;
    transform: translateY(0) scale(1);
  }
}

#message.is-error {
  background-color: var(--error);
  border-color: rgba(239, 68, 68, 0.45);
}

#message.is-success {
  background-color: var(--success);
  border-color: rgba(34, 197, 94, 0.45);
}

#message.is-warning {
  background-color: var(--warning);
  border-color: rgba(245, 158, 11, 0.45);
}

#message.is-hint {
  background-color: rgba(59, 130, 246, 0.25);
  border-color: rgba(59, 130, 246, 0.4);
}

@keyframes shake {
  0% {
    transform: translateX(0);
  }
  20% {
    transform: translateX(-6px);
  }
  40% {
    transform: translateX(6px);
  }
  60% {
    transform: translateX(-4px);
  }
  80% {
    transform: translateX(4px);
  }
  100% {
    transform: translateX(0);
  }
}

#message.shake {
  animation: shake 320ms ease-in-out;
}

/* Respect reduced motion */
@media (prefers-reduced-motion: reduce) {
  body {
    animation: none;
  }
  h1 {
    animation: none;
  }
  #message.is-visible {
    animation: none;
  }
  #message.shake {
    animation: none;
  }
}