:root {
  --bg: #0b0e18;
  --fg: #e5e7eb;
  --muted: #9aa1b0;
  --accent: #f87171;
  --accent-2: #22d3ee;
  --shadow: 0 10px 30px rgba(0, 0, 0, 0.5);
}

[data-theme="light"] {
  --bg: #f6f7fb;
  --fg: #0f1222;
  --muted: #6b7280;
  --accent: #ef4444;
  --accent-2: #06b6d4;
  --shadow: 0 10px 30px rgba(2, 6, 23, 0.15);
}

* { box-sizing: border-box; }

html, body {
  height: 100%;
}

body {
  margin: 0;
  font-family: ui-sans-serif, system-ui, -apple-system, Segoe UI, Roboto, Noto Sans, Ubuntu, Cantarell, Helvetica Neue, Arial, Apple Color Emoji, Segoe UI Emoji;
  color: var(--fg);
  background: radial-gradient(1200px 800px at 10% 10%, rgba(239, 68, 68, 0.08), transparent 60%),
              radial-gradient(1000px 700px at 90% 20%, rgba(6, 182, 212, 0.08), transparent 60%),
              linear-gradient(180deg, var(--bg), var(--bg));
  overflow: hidden;
}

.container {
  min-height: 100%;
  display: grid;
  align-content: center;
  justify-items: center;
  text-align: center;
  padding: 24px;
}

.title {
  margin: 0;
  font-weight: 800;
  line-height: 1.05;
  letter-spacing: 0.02em;
  font-size: clamp(2.5rem, 8vw, 7rem);
  text-shadow: var(--shadow);
}

.title .char {
  display: inline-block;
  will-change: transform, opacity, filter;
}

.hint {
  position: absolute;
  bottom: 20px;
  left: 50%;
  transform: translateX(-50%);
  margin: 0;
  color: var(--muted);
  font-size: 0.95rem;
  user-select: none;
  pointer-events: none;
}

.theme-toggle {
  position: fixed;
  bottom: 20px;
  right: 20px;
  width: 56px;
  height: 56px;
  border-radius: 14px;
  border: none;
  background: linear-gradient(180deg, var(--accent), var(--accent-2));
  color: white;
  box-shadow: var(--shadow);
  display: grid;
  place-items: center;
  cursor: pointer;
  transition: transform 0.15s ease;
}

.theme-toggle:active {
  transform: scale(0.97);
}

.theme-toggle .icon {
  position: absolute;
  font-size: 22px;
  transition: opacity 0.25s ease, transform 0.25s ease;
}

.theme-toggle .sun {
  opacity: 0;
  transform: translateY(6px) scale(0.9);
}

[data-theme="light"] .theme-toggle .moon {
  opacity: 0;
  transform: translateY(-6px) scale(0.9);
}

.sparkle {
  position: fixed;
  width: 8px;
  height: 8px;
  border-radius: 999px;
  background: linear-gradient(180deg, var(--accent-2), var(--accent));
  box-shadow: 0 0 0 2px rgba(255,255,255,0.6) inset, 0 0 24px rgba(239, 68, 68, 0.6);
  pointer-events: none;
}

.subtitle {
  margin-top: 40px;
  width: auto;
  max-width: none;
  text-align: center;
  font-size: clamp(1rem, 2.5vw, 1.5rem);
  color: var(--muted);
  position: relative;
  display: inline-block;
  font-weight: 600;
  letter-spacing: 0.01em;
}

.subtitle .char {
  display: inline-block;
  will-change: transform, opacity;
}

.subtitle-shine {
  position: absolute;
  inset: 0;
  color: transparent;
  background-image: linear-gradient(90deg, rgba(255,255,255,0), rgba(255,255,255,0.0) 40%, rgba(255,255,255,0.9) 50%, rgba(255,255,255,0.0) 60%, rgba(255,255,255,0));
  -webkit-background-clip: text;
  background-clip: text;
  background-size: 200% 100%;
  pointer-events: none;
  opacity: 0.35;
}

.subtitle .char.accent {
  color: var(--accent);
  text-shadow: 0 0 10px rgba(239, 68, 68, 0.45);
}

[data-theme="dark"] .subtitle .char.accent {
  text-shadow: 0 0 12px rgba(248, 113, 113, 0.65);
}