:root {
  color-scheme: dark;
  font-family: Inter, system-ui, -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
  background: #0f172a;
  color: #e2e8f0;
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  min-height: 100vh;
  display: grid;
  place-items: center;
  padding: 24px;
  background: radial-gradient(circle at top, rgba(56, 189, 248, 0.16), transparent 28%),
    radial-gradient(circle at bottom right, rgba(168, 85, 247, 0.14), transparent 24%),
    linear-gradient(180deg, #020617 0%, #0f172a 100%);
}

.app-shell {
  position: relative;
  width: min(510px, 100%);
}

.floating-image {
  position: absolute;
  right: -340px;
  top: 1px;
  width: 168px;
  height: 228px;
  border-radius: 32px;
  background: radial-gradient(circle at top, rgba(56, 189, 248, 0.24), rgba(99, 102, 241, 0.24)), url('floating-image.png');
  background-size: cover;
  background-position: center;
  box-shadow: 0 28px 60px rgba(15, 23, 42, 0.4);
  animation: float 4.5s ease-in-out infinite;
  border: 1px solid rgba(148, 163, 184, 0.15);
}

@keyframes float {
  0%, 100% {
    transform: translateY(0);
  }
  50% {
    transform: translateY(-14px);
  }
}

.card {
  border-radius: 32px;
  background: rgba(15, 23, 42, 0.88);
  border: 1px solid rgba(148, 163, 184, 0.12);
  backdrop-filter: blur(18px);
  box-shadow: 0 30px 60px rgba(0, 0, 0, 0.18);
  padding: 32px;
  display: none;
}

.card.active {
  display: block;
}

.logo {
  font-size: 2rem;
  letter-spacing: 0.28em;
  text-transform: uppercase;
  font-weight: 700;
  margin-bottom: 18px;
  color: #7dd3fc;
}

.card-menu {
  display: grid;
  gap: 18px;
  justify-items: center;
}

.menu-title,
.panel-title {
  font-size: 1.1rem;
  margin-bottom: 20px;
  color: #cbd5e1;
}

.menu-button,
.control-button,
.back-button {
  border: none;
  border-radius: 10px;
  background: linear-gradient(135deg, #38bdf8, #192e57);
  color: #ffffff;
  padding: 18px 20px;
  font-size: 1rem;
  cursor: pointer;
  font-weight: 600;
  transition: transform 180ms ease, box-shadow 180ms ease, background 180ms ease;
}

.menu-button {
  width: 40%;
}

.control-button,
.back-button {
  width: 100%;
}

.menu-button:hover,
.control-button:hover,
.back-button:hover {
  transform: translateY(-2px);
  box-shadow: 0 18px 30px rgba(56, 189, 248, 0.18);
}

.back-button {
  max-width: 140px;
  margin-bottom: 24px;
  background: rgba(148, 163, 184, 0.14);
  color: #cbd5e1;
}

.top-bar {
  display: flex;
  align-items: center;
  gap: 14px;
}

.display-box {
  margin: 28px 0;
  padding: 30px 28px;
  border-radius: 28px;
  background: rgba(30, 41, 59, 0.9);
  border: 1px solid rgba(148, 163, 184, 0.1);
  display: grid;
  place-items: center;
}

.display-box.custom {
  gap: 18px;
}

.time-value {
  font-size: clamp(3rem, 7vw, 5rem);
  font-weight: 800;
  letter-spacing: 0.04em;
  color: #f8fafc;
}

.custom-label {
  font-size: 0.95rem;
  color: #94a3b8;
}

#customInput {
  width: 100%;
  max-width: 180px;
  padding: 14px 16px;
  border-radius: 16px;
  border: 1px solid rgba(148, 163, 184, 0.18);
  background: rgba(15, 23, 42, 0.76);
  color: #e2e8f0;
  font-size: 1rem;
  text-align: center;
}

.custom-input-row {
  display: flex;
  gap: 12px;
  width: 100%;
  align-items: center;
  justify-content: center;
  flex-wrap: wrap;
}

#customUnit {
  width: 100%;
  max-width: 140px;
  padding: 14px 16px;
  border-radius: 16px;
  border: 1px solid rgba(148, 163, 184, 0.18);
  background: rgba(15, 23, 42, 0.76);
  color: #e2e8f0;
  font-size: 1rem;
}

.controls {
  display: grid;
  gap: 16px;
}

@media (min-width: 520px) {
  .controls {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }
}

@media (max-width: 420px) {
  .card {
    padding: 24px;
  }
  .menu-button,
  .control-button,
  .back-button {
    padding: 16px 18px;
  }
  .floating-image {
    display: none;
  }
}