:root {
  --bg: #0f172a;
  --text: #e5e7eb;
  --accent: #f97316;
  --accent-strong: #fb923c;
  --card: rgba(15, 23, 42, 0.9);
}

body.light {
  --bg: #f9fafb;
  --text: #0f172a;
  --accent: #ea580c;
  --accent-strong: #c2410c;
  --card: #ffffff;
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  font-family: system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  background: radial-gradient(circle at top, rgba(251, 146, 60, 0.25), transparent 50%),
              var(--bg);
  color: var(--text);
  display: flex;
  align-items: center;
  justify-content: center;
  min-height: 100vh;
  padding: 1rem;
  transition: background 0.3s ease, color 0.3s ease;
}

.app {
  width: 100%;
  max-width: 420px;
  padding: 1.5rem 1.6rem 2rem;
  border-radius: 1rem;
  background: var(--card);
  box-shadow: 0 18px 40px rgba(15, 23, 42, 0.45);
  text-align: center;
}

/* Headings & text */

h1 {
  margin: 0 0 0.4rem;
  font-size: clamp(1.7rem, 3.5vw, 2.1rem);
}

.subtitle {
  margin: 0 0 1.4rem;
  font-size: 0.95rem;
  opacity: 0.8;
}

#countdown {
  font-size: clamp(1.8rem, 5vw, 2.4rem);
  letter-spacing: 0.08em;
  margin-bottom: 0.7rem;
  word-spacing: 0.25em;
}

#message {
  font-size: 1rem;
  color: var(--accent-strong);
  margin-bottom: 0.3rem;
}

/* Toggle button */

button.toggle {
  background: transparent;
  border: 1px solid rgba(148, 163, 184, 0.9);
  border-radius: 999px;
  padding: 0.35rem 0.9rem;
  font-size: 0.85rem;
  cursor: pointer;
  color: var(--text);
  transition: background 0.2s ease, color 0.2s ease, border-color 0.2s ease,
              transform 0.1s ease;
  margin-bottom: 1.1rem;
  align-self: flex-end;
}

button.toggle:hover {
  background: var(--text);
  color: var(--bg);
  border-color: var(--text);
  transform: translateY(-1px);
}

button.toggle:active {
  transform: translateY(0);
}

/* Fireworks */

.fireworks-container {
  pointer-events: none;
  position: fixed;
  inset: 0;
  overflow: hidden;
  z-index: 999;
}

.firework {
  position: absolute;
  width: 4px;
  height: 4px;
  border-radius: 999px;
  background: var(--accent-strong);
  opacity: 0;
  animation: explode 1s ease-out forwards;
}

@keyframes explode {
  0% {
    transform: translate3d(0, 0, 0) scale(1);
    opacity: 1;
  }
  80% {
    opacity: 1;
  }
  100% {
    transform: translate3d(var(--dx), var(--dy), 0) scale(0.4);
    opacity: 0;
  }
}

/* Smaller screens */

@media (max-width: 480px) {
  .app {
    padding: 1.3rem 1.2rem 1.7rem;
    border-radius: 0.9rem;
  }
  #countdown {
    letter-spacing: 0.06em;
  }
}