* {
  box-sizing: border-box;
}

html {
  overflow: hidden;
  height: 100%;
}

body {
  font-family: 'SF Mono', 'Menlo', 'Monaco', monospace;
  background: #fafafa;
  color: #333;
  height: 100%;
  display: flex;
  align-items: center;
  justify-content: center;
  margin: 0;
  padding: 20px;
  overflow: hidden;
}

.container {
  text-align: center;
  max-height: 100%;
  display: flex;
  flex-direction: column;
  justify-content: center;
}

h1 {
  font-size: 1rem;
  font-weight: 400;
  letter-spacing: 0.2em;
  text-transform: uppercase;
  color: #999;
  margin: 0 0 1.5rem 0;
}

.section {
  margin-bottom: 1.5rem;
}

.section h2 {
  font-size: 0.7rem;
  font-weight: 400;
  letter-spacing: 0.2em;
  text-transform: uppercase;
  color: #aaa;
  margin: 0 0 0.75rem 0;
}

.age-toggle {
  margin-bottom: 0.75rem;
}

.age-toggle button {
  font-family: inherit;
  font-size: 0.7rem;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  background: none;
  border: 1px solid #ddd;
  padding: 0.5rem 1rem;
  cursor: pointer;
  color: #999;
  transition: all 0.2s;
}

.age-toggle button:first-child {
  border-radius: 4px 0 0 4px;
}

.age-toggle button:last-child {
  border-radius: 0 4px 4px 0;
}

.age-toggle button:not(:first-child) {
  margin-left: -1px;
}

.age-toggle button.active {
  background: #111;
  color: #fff;
  border-color: #111;
}

.age-display {
  font-size: 4rem;
  font-weight: 300;
  color: #111;
}

.age-unit {
  font-size: 0.75rem;
  letter-spacing: 0.15em;
  text-transform: uppercase;
  color: #aaa;
  margin-left: 0.5rem;
  vertical-align: middle;
}

.countdown {
  display: flex;
  gap: 2rem;
  justify-content: center;
}

.unit {
  display: flex;
  flex-direction: column;
  align-items: center;
}

.unit span {
  font-size: 4rem;
  font-weight: 300;
  line-height: 1;
  color: #111;
}

.unit label {
  font-size: 0.75rem;
  letter-spacing: 0.15em;
  text-transform: uppercase;
  color: #aaa;
  margin-top: 0.5rem;
}

@media (max-width: 600px) {
  .countdown {
    gap: 1rem;
  }

  .unit span {
    font-size: 2.5rem;
  }

  .unit label {
    font-size: 0.6rem;
  }

  .age-display {
    font-size: 2.5rem;
  }
}

@media (max-width: 400px) {
  .countdown {
    flex-wrap: wrap;
    gap: 0.5rem;
  }

  .unit span {
    font-size: 2rem;
  }
}