/*
  Design tokens:
  Centralizing the colors and spacing here makes small visual changes easy.
  Update a value once and every use of that variable follows automatically.
*/
:root {
  --page-background: #f5f7fb;
  --card-background: #ffffff;
  --heading-color: #1f2937;
  --text-color: #4b5563;
  --card-radius: 16px;
  --card-shadow: 0 12px 32px rgba(31, 41, 55, 0.12);
}

/*
  Reset the browser's default page margin, then use CSS Grid to place the
  greeting card in the exact center of the available viewport.
*/
body {
  min-height: 100vh;
  margin: 0;
  display: grid;
  place-items: center;
  padding: 24px;
  box-sizing: border-box;
  background: var(--page-background);
  color: var(--text-color);
  font-family: Arial, Helvetica, sans-serif;
}

/*
  The card keeps the content readable on wide displays while `width: 100%`
  lets it shrink gracefully within the body padding on narrow screens.
*/
.welcome-card {
  width: 100%;
  max-width: 420px;
  padding: 48px 32px;
  box-sizing: border-box;
  text-align: center;
  background: var(--card-background);
  border-radius: var(--card-radius);
  box-shadow: var(--card-shadow);
}

/* Keep the greeting prominent without relying on an overly large fixed size. */
h1 {
  margin: 0;
  color: var(--heading-color);
  font-size: clamp(2rem, 6vw, 3.5rem);
}

/* Separate the supporting line from the heading while preserving simple flow. */
p {
  margin: 16px 0 0;
  font-size: 1.125rem;
}