/*
  Centralized design values make routine visual changes quick and consistent.
  For example, update --accent to change the highlighted color site-wide.
*/
:root {
  --page-background: #f4f7fb;
  --card-background: #ffffff;
  --text-color: #1f2937;
  --accent: #2563eb;
  --shadow-color: rgb(31 41 55 / 12%);
}

/*
  Remove browser-default spacing and make the page fill the full viewport.
  This creates a reliable foundation for vertically and horizontally centering
  the welcome card.
*/
body {
  margin: 0;
  min-width: 320px;
  min-height: 100vh;
  background: var(--page-background);
  color: var(--text-color);
  font-family: Arial, Helvetica, sans-serif;
}

/* Use CSS Grid to center the only content block without fixed positioning. */
.page-shell {
  display: grid;
  min-height: 100vh;
  place-items: center;
  padding: 1.5rem;
  box-sizing: border-box;
}

/*
  The card stays readable on narrow screens because its width is fluid, while
  max-width prevents it from becoming overly wide on large displays.
*/
.welcome-card {
  width: min(100%, 36rem);
  padding: 3rem 2rem;
  text-align: center;
  background: var(--card-background);
  border-radius: 1rem;
  box-shadow: 0 1rem 2.5rem var(--shadow-color);
}

/* Keep the title prominent, responsive, and visibly connected to the accent. */
h1 {
  margin: 0;
  color: var(--accent);
  font-size: clamp(2rem, 6vw, 3.5rem);
}

/* A separated paragraph improves readability without introducing extra markup. */
p {
  margin: 1rem 0 0;
  font-size: clamp(1rem, 3vw, 1.25rem);
}