:root {
  /* Light mode colors */
  --bg-color: oklch(95% 0.01 260);
  --text-color: oklch(25% 0.02 260);
  --accent-blue: oklch(60% 0.15 250);
  --surface-color: rgba(255, 255, 255, 0.7);
  --border-color: rgba(255, 255, 255, 0.2);
  --shadow-sm: 0 2px 4px rgba(0, 0, 0, 0.05);
  --shadow-lg: 0 10px 25px -5px rgba(0, 0, 0, 0.1), 0 8px 10px -6px rgba(0, 0, 0, 0.1);
  --font-family: 'Pretendard', -apple-system, BlinkMacSystemFont, system-ui, Roboto, sans-serif;
  --noise-opacity: 0.4;
}

[data-theme="dark"] {
  /* Dark mode colors */
  --bg-color: oklch(20% 0.02 260);
  --text-color: oklch(90% 0.01 260);
  --accent-blue: oklch(70% 0.15 250);
  --surface-color: rgba(30, 41, 59, 0.7);
  --border-color: rgba(255, 255, 255, 0.1);
  --shadow-lg: 0 10px 25px -5px rgba(0, 0, 0, 0.5), 0 8px 10px -6px rgba(0, 0, 0, 0.5);
  --noise-opacity: 0.1;
}

* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

body {
  background-color: var(--bg-color);
  color: var(--text-color);
  font-family: var(--font-family);
  min-height: 100dvh;
  display: flex;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  transition: background-color 0.3s ease, color 0.3s ease;
  position: relative;
  overflow: hidden;
}

/* Noise texture effect */
body::before {
  content: "";
  position: absolute;
  inset: 0;
  background-image: url("data:image/svg+xml,%3Csvg viewBox='0 0 200 200' xmlns='http://www.w3.org/2000/svg'%3E%3Cfilter id='noiseFilter'%3E%3CfeTurbulence type='fractalNoise' baseFrequency='0.65' numOctaves='3' stitchTiles='stitch'/%3E%3C/filter%3E%3Crect width='100%25' height='100%25' filter='url(%23noiseFilter)'/%3E%3C/svg%3E");
  background-repeat: repeat;
  opacity: var(--noise-opacity);
  pointer-events: none;
  z-index: -1;
}

.app-container {
  width: 100%;
  max-width: 600px;
  padding-inline: 1rem;
  z-index: 1;
}

.theme-toggle {
  position: fixed;
  top: 1.5rem;
  right: 1.5rem;
  background: var(--surface-color);
  backdrop-filter: blur(8px);
  border: 1px solid var(--border-color);
  padding: 0.75rem;
  border-radius: 1rem;
  cursor: pointer;
  color: var(--text-color);
  box-shadow: var(--shadow-sm);
  transition: all 0.2s ease;
  z-index: 10;
  display: flex;
  align-items: center;
  justify-content: center;
}

.theme-toggle:hover {
  transform: scale(1.05);
  box-shadow: var(--shadow-lg);
}