:root {
  /* Light Theme Colors (Default) */
  --bg-color: oklch(98% 0.01 200);
  --text-color: oklch(20% 0.02 200);
  --accent-color: oklch(60% 0.15 250);
  --card-bg: oklch(100% 0 0);
  --shadow: 0 10px 30px -10px oklch(0% 0 0 / 0.1);
  --button-bg: var(--accent-color);
  --button-text: oklch(100% 0 0);
  
  transition: background-color 0.3s ease, color 0.3s ease;
}

[data-theme="dark"] {
  --bg-color: oklch(15% 0.02 250);
  --text-color: oklch(90% 0.02 250);
  --accent-color: oklch(75% 0.12 250);
  --card-bg: oklch(20% 0.02 250);
  --shadow: 0 10px 30px -10px oklch(0% 0 0 / 0.5);
}

body {
  margin: 0;
  padding: 0;
  font-family: system-ui, -apple-system, sans-serif;
  background-color: var(--bg-color);
  color: var(--text-color);
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  min-height: 100vh;
  text-align: center;
}

.container {
  background-color: var(--card-bg);
  padding: 2rem;
  border-radius: 1.5rem;
  box-shadow: var(--shadow);
  max-width: 400px;
  width: 90%;
}

h1 {
  font-size: 2.5rem;
  margin-bottom: 1rem;
  font-weight: 800;
  background: linear-gradient(to right, var(--accent-color), oklch(70% 0.2 300));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
}

button {
  cursor: pointer;
  border: none;
  padding: 0.8rem 1.5rem;
  border-radius: 0.8rem;
  font-size: 1rem;
  font-weight: 600;
  background-color: var(--button-bg);
  color: var(--button-text);
  transition: transform 0.2s, filter 0.2s;
  box-shadow: 0 4px 12px -2px oklch(0% 0 0 / 0.2);
}

button:hover {
  transform: translateY(-2px);
  filter: brightness(1.1);
}

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

#theme-toggle {
  position: absolute;
  top: 1rem;
  right: 1rem;
  background: var(--card-bg);
  color: var(--text-color);
  border: 1px solid oklch(50% 0 0 / 0.1);
}