:root {
  --bg: #f5f7fb;
  --card: rgba(255,255,255,0.85);
  --text: #0f172a;
  --muted: #64748b;
  --accent: #2563eb;
  --accent-soft: rgba(37,99,235,.15);
  --border: rgba(0,0,0,.08);
}

[data-theme="dark"] {
  --bg: #0b1220;
  --card: rgba(18,26,48,.85);
  --text: #e5e7eb;
  --muted: #9ca3af;
  --accent: #38bdf8;
  --accent-soft: rgba(56,189,248,.18);
  --border: rgba(255,255,255,.12);
}

* {
  box-sizing: border-box;
  font-family: Inter, system-ui, -apple-system, sans-serif;
}

body {
  margin: 0;
  background:
    radial-gradient(circle at top, var(--accent-soft), transparent 45%),
    var(--bg);
  color: var(--text);
  transition: background .4s, color .4s;
}

header {
  padding: 2.5rem 1rem 1.5rem;
  text-align: center;
}

header h1 {
  font-size: 2.3rem;
  margin-bottom: .4rem;
}

header p {
  color: var(--muted);
}

.container {
  max-width: 960px;
  margin: auto;
  padding: 1rem;
}

.card {
  background: var(--card);
  backdrop-filter: blur(18px);
  border-radius: 20px;
  padding: 2rem;
  border: 1px solid var(--border);
  box-shadow: 0 25px 60px rgba(0,0,0,.18);
  animation: rise .6s ease;
}

@keyframes rise {
  from {opacity:0; transform: translateY(25px)}
}

label {
  display: block;
  margin-top: 1.2rem;
  font-size: .85rem;
  color: var(--muted);
}

input {
  width: 100%;
  margin-top: .35rem;
}

input[type="number"] {
  padding: .7rem .8rem;
  border-radius: 12px;
  border: 1px solid var(--border);
  background: transparent;
  color: var(--text);
}

input[type="range"] {
  pointer-events: auto;
  accent-color: var(--accent);
}

.result {
  margin-top: 1.6rem;
  padding: 1.1rem;
  border-radius: 16px;
  background: linear-gradient(
    135deg,
    var(--accent-soft),
    transparent
  );
  font-size: 1.15rem;
}

.controls {
  display: flex;
  justify-content: space-between;
  margin-bottom: 1rem;
}

.toggle {
  cursor: pointer;
  padding: .45rem .9rem;
  border-radius: 999px;
  background: var(--accent-soft);
  font-size: .8rem;
  user-select: none;
  transition: transform .2s;
}

.toggle:hover {
  transform: scale(1.06);
}

.grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(240px,1fr));
  gap: 1.2rem;
}

.card-link {
  text-decoration: none;
  color: inherit;
}

.card-link .card:hover {
  transform: translateY(-6px);
  transition: .3s;
}

canvas {
  margin-top: 1.8rem;
}

footer {
  text-align: center;
  font-size: .75rem;
  color: var(--muted);
  margin: 3rem 0 1rem;
}