:root {
  --bg-main: #ffffff;
  --bg-card: #f8fafc;
  --bg-checked: #2563eb;
  --border-light: #e2e8f0;
  --border-dark: #cbd5e1;
  --text-main: #0f172a;
  --text-sub: #64748b;
}

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

body {
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
  background: var(--bg-main);
  color: var(--text-main);
  min-height: 100vh;
  display: flex;
  justify-content: center;
  align-items: center;
  padding: 40px 20px;
}

.page-wrapper {
  max-width: 900px;
  width: 100%;
  text-align: center;
}

h1 {
  font-size: 2.5rem;
  font-weight: 800;
  letter-spacing: -0.025em;
  margin-bottom: 8px;
}

.subtitle {
  color: var(--text-sub);
  font-size: 1.1rem;
  margin-bottom: 40px;
}

.feature-card-container {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
  gap: 20px;
}

.feature-card {
  position: relative;
  background: var(--bg-card);
  border: 2px solid var(--border-light);
  border-radius: 16px;
  padding: 28px 24px;
  text-align: left;
  cursor: pointer;
  display: flex;
  flex-direction: column;
  transition:
    transform 0.2s ease,
    box-shadow 0.2s ease;
}

.feature-card:hover {
  transform: translateY(-4px);
  border-color: var(--border-dark);
  box-shadow: 0 10px 25px -5px rgba(0, 0, 0, 0.05);
}

.card-icon {
  font-size: 1.5rem;
  margin-bottom: 16px;
}

.feature-card h4 {
  font-size: 1.15rem;
  font-weight: 600;
  margin-bottom: 8px;
}

.feature-card p {
  color: var(--text-sub);
  font-size: 0.9rem;
}

.feature-card input[type='checkbox'] {
  appearance: none;
  border-width: 2px;
  border-color: var(--border-dark);
  border-style: solid;
  position: absolute;
  top: 20px;
  right: 20px;
  width: 22px;
  height: 22px;
  background-color: var(--bg-main);
  border-radius: 6px;
  cursor: pointer;
  display: grid;
  place-content: center;
}

.feature-card input[type='checkbox']:checked {
  background-color: var(--bg-checked);
  border-color: var(--bg-checked);
}

.feature-card input[type='checkbox']:checked::after {
  content: '✓';
  color: var(--bg-main);
  font-size: 0.85rem;
  font-weight: bold;
}

.feature-card:has(input:checked) {
  border-color: var(--bg-checked);
  background-color: #f0f5ff;
}