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

:root {
  --bg: radial-gradient(circle at top, #ffecd2, #fcb69f);
  --card-bg: rgba(255, 255, 255, 0.9);
  --text: #1f2933;
  --muted: rgba(31, 41, 51, 0.7);
  --shadow: 0 15px 35px rgba(0, 0, 0, 0.08);
  --shadow-hover: 0 20px 40px rgba(0, 0, 0, 0.12);
  --accent: #ec4899;
}

body.dark {
  --bg: radial-gradient(circle at top, #020617, #0f172a);
  --card-bg: rgba(15, 23, 42, 0.96);
  --text: #e5e7eb;
  --muted: rgba(148, 163, 184, 0.9);
  --shadow: 0 15px 35px rgba(0, 0, 0, 0.6);
  --shadow-hover: 0 20px 40px rgba(0, 0, 0, 0.9);
  --accent: #38bdf8;
}

body {
  margin: 0;
  font-family: system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  background: var(--bg);
  min-height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--text);
  transition: background 0.4s ease, color 0.4s ease;
}

/* Theme toggle button */

#theme-toggle {
  position: fixed;
  top: 1rem;
  right: 1rem;
  border: none;
  border-radius: 999px;
  padding: 0.4rem 0.8rem;
  display: inline-flex;
  align-items: center;
  gap: 0.3rem;
  cursor: pointer;
  font-size: 0.85rem;
  background: rgba(255, 255, 255, 0.85);
  color: #111827;
  box-shadow: 0 6px 18px rgba(0, 0, 0, 0.12);
  backdrop-filter: blur(10px);
  z-index: 50;
  transition: transform 0.12s ease, box-shadow 0.12s ease, background 0.3s ease;
}

body.dark #theme-toggle {
  background: rgba(15, 23, 42, 0.9);
  color: #e5e7eb;
}

#theme-toggle .icon {
  font-size: 1.1rem;
}

#theme-toggle:hover {
  transform: translateY(-1px);
  box-shadow: 0 10px 22px rgba(0, 0, 0, 0.18);
}

/* Layout */

.container {
  max-width: 1100px;
  width: 100%;
  padding: 2rem 1.5rem 3rem;
}

h1 {
  text-align: center;
  margin-bottom: 0.25rem;
  letter-spacing: 0.05em;
  text-transform: uppercase;
  font-size: 1.8rem;
}

.subtitle {
  text-align: center;
  margin-top: 0;
  margin-bottom: 2rem;
  opacity: 0.8;
  color: var(--muted);
}

/* BIRTHDAY BANNER */

.banner {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 0.6rem;
  margin-bottom: 1.5rem;
  padding: 0.75rem 1.25rem;
  border-radius: 999px;
  background: linear-gradient(90deg, #f97316, #ec4899, #3b82f6);
  color: #fefce8;
  font-weight: 600;
  font-size: 1rem;
  box-shadow: 0 12px 30px rgba(0, 0, 0, 0.18);
  text-align: center;
  letter-spacing: 0.03em;
  text-transform: uppercase;
  animation: banner-pop 0.3s ease-out;
}

body.dark .banner {
  box-shadow: 0 16px 40px rgba(0, 0, 0, 0.7);
}

.banner.hidden {
  display: none;
}

.banner-emoji {
  font-size: 1.2rem;
}

@keyframes banner-pop {
  0% {
    transform: translateY(-8px) scale(0.96);
    opacity: 0;
  }
  100% {
    transform: translateY(0) scale(1);
    opacity: 1;
  }
}

/* Countdowns */

.countdowns {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(230px, 1fr));
  gap: 1.5rem;
}

.countdown-card {
  background: var(--card-bg);
  border-radius: 1.25rem;
  padding: 1.5rem 1.5rem 1.75rem;
  box-shadow: var(--shadow);
  backdrop-filter: blur(10px);
  transition: transform 0.16s ease, box-shadow 0.16s ease, background 0.3s ease, border 0.3s ease;
  border: 1px solid transparent;
  position: relative;
  overflow: hidden;
}

.countdown-card:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-hover);
}

.countdown-card h2.name {
  margin: 0 0 0.25rem;
  font-size: 1.25rem;
}

.countdown-card .date-label {
  margin: 0 0 1rem;
  font-size: 0.9rem;
  color: var(--muted);
}

/* Celebration state */

.countdown-card.is-birthday {
  border-color: var(--accent);
  box-shadow: 0 0 0 2px rgba(236, 72, 153, 0.25), var(--shadow-hover);
}

.countdown-card.is-birthday::after {
  content: "🎉 Happy Birthday!";
  position: absolute;
  right: 12px;
  top: 12px;
  font-size: 0.85rem;
  padding: 0.2rem 0.6rem;
  border-radius: 999px;
  background: rgba(255, 255, 255, 0.85);
  color: #be185d;
}

body.dark .countdown-card.is-birthday::after {
  background: rgba(15, 23, 42, 0.95);
  color: #f472b6;
}

/* Time layout */

.time-parts {
  display: flex;
  justify-content: space-between;
  gap: 0.75rem;
}

.part {
  flex: 1;
  text-align: center;
}

.part .value {
  display: block;
  font-size: 1.4rem;
  font-weight: 700;
}

.part .label {
  display: block;
  font-size: 0.75rem;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  opacity: 0.7;
}

/* Confetti */

#confetti-root {
  position: fixed;
  inset: 0;
  pointer-events: none;
  overflow: hidden;
  z-index: 40;
}

.confetti-piece {
  position: absolute;
  width: 8px;
  height: 14px;
  border-radius: 2px;
  animation-name: confetti-fall;
  animation-timing-function: linear;
  animation-iteration-count: 1;
}

@keyframes confetti-fall {
  0% {
    transform: translate3d(0, -110%, 0) rotateZ(0deg);
    opacity: 1;
  }
  100% {
    transform: translate3d(0, 110vh, 0) rotateZ(360deg);
    opacity: 0;
  }
}

@media (max-width: 600px) {
  .container {
    padding: 1.5rem 1rem 2rem;
  }

  h1 {
    font-size: 1.5rem;
  }

  #theme-toggle {
    top: 0.8rem;
    right: 0.8rem;
  }
}